diff options
Diffstat (limited to 'old')
35 files changed, 0 insertions, 24676 deletions
diff --git a/old/69904-0.txt b/old/69904-0.txt deleted file mode 100644 index b91b3ea..0000000 --- a/old/69904-0.txt +++ /dev/null @@ -1,10059 +0,0 @@ -The Project Gutenberg eBook of Animal intelligence, by Edward Lee -Thorndike - -This eBook is for the use of anyone anywhere in the United States and -most other parts of the world at no cost and with almost no restrictions -whatsoever. You may copy it, give it away or re-use it under the terms -of the Project Gutenberg License included with this eBook or online at -www.gutenberg.org. If you are not located in the United States, you -will have to check the laws of the country where you are located before -using this eBook. - -Title: Animal intelligence - Experimental studies - -Author: Edward Lee Thorndike - -Release Date: January 29, 2023 [eBook #69904] - -Language: English - -Produced by: Emmanuel Ackerman, Kobus Meyer and the Online Distributed - Proofreading Team at https://www.pgdp.net (This file was - produced from images generously made available by The - Internet Archive) - -*** START OF THE PROJECT GUTENBERG EBOOK ANIMAL INTELLIGENCE *** - - - - - - -ANIMAL INTELLIGENCE - - - - - [Illustration] - - THE MACMILLAN COMPANY - NEW YORK · BOSTON · CHICAGO - SAN FRANCISCO - - MACMILLAN & CO., LIMITED - LONDON · BOMBAY · CALCUTTA - MELBOURNE - - THE MACMILLAN CO. OF CANADA, LTD. - TORONTO - - - - - ANIMAL INTELLIGENCE - - EXPERIMENTAL STUDIES - - BY - EDWARD L. THORNDIKE - TEACHERS COLLEGE, COLUMBIA UNIVERSITY - - New York - THE MACMILLAN COMPANY - 1911 - - _All rights reserved_ - - COPYRIGHT, 1911, - BY THE MACMILLAN COMPANY. - - Set up and electrotyped. Published June, 1911. - - Norwood Press - J. S. Cushing Co.—Berwick & Smith Co. - Norwood, Mass., U.S.A. - - - - -PREFACE - - -The main purpose of this volume is to make accessible to students of -psychology and biology the author’s experimental studies of animal -intellect and behavior.[1] These studies have, I am informed by teachers -of comparative psychology, a twofold interest. Since they represent the -first deliberate and extended application of the experimental method in -animal psychology, they are a useful introduction to the later literature -of that subject. They mark the change from books of general argumentation -on the basis of common experience interpreted in terms of the faculty -psychology, to monographs reporting detailed and often highly technical -experiments interpreted in terms of original and acquired connections -between situation and response. Since they represent the point of view -and the method of present animal psychology, but in the case of very -general and simple problems, they are useful also as readings for -students who need a general acquaintance with some sample of experimental -work in this field. - -It has seemed best to leave the texts unaltered except for the correction -of typographical errors, renumbering of tables and figures, and redrawing -the latter. In a few places, where the original text has been found -likely to be misunderstood, brief notes have been added. It is hard -to resist the impulse to temper the style, especially of the ‘Animal -Intelligence,’ with a certain sobriety and restraint. What one writes -at the age of twenty-three is likely to irritate oneself a dozen years -later, as it doubtless irritated others at the time. The charitable -reader may allay his irritation by the thought that a degree of -exuberance, even of arrogance, is proper to youth. - -To the reports of experimental studies are added two new essays dealing -with the general laws of human and animal learning. - - JANUARY, 1911. - - - - -CONTENTS - - - PAGE - - THE STUDY OF CONSCIOUSNESS AND THE STUDY OF BEHAVIOR 1 - - ANIMAL INTELLIGENCE 20 - - Introduction 20 - - Description of Apparatus 29 - - Experiments with Cats 35 - - Experiments with Dogs 56 - - Experiments with Chicks 61 - - Reasoning or Inference 67 - - Imitation 76 - - In Chicks 81 - - In Cats 85 - - In Dogs 92 - - The Mental Fact in Association 98 - - Association by Similarity and the Formation of Concepts 116 - - Criticism of Previous Theories 125 - - Delicacy of Association 128 - - Complexity of Associations 132 - - Number of Associations 135 - - Permanence of Associations 138 - - Inhibition of Instincts by Habit 142 - - Attention 144 - - The Social Consciousness of Animals 146 - - Interaction 147 - - Applications to Pedagogy, Anthropology, etc. 149 - - Conclusion 153 - - THE INSTINCTIVE REACTIONS OF YOUNG CHICKS 156 - - A NOTE ON THE PSYCHOLOGY OF FISHES 169 - - THE MENTAL LIFE OF THE MONKEYS 172 - - Introduction 173 - - Apparatus 177 - - Learning without Tuition 182 - - Tests with Mechanisms 184 - - Tests with Signals 195 - - Experiments on the Influence of Tuition 209 - - Introduction 209 - - Imitation of Human Beings 211 - - Imitation of Other Monkeys 219 - - Learning apart from Motor Impulses 222 - - General Mental Development of the Monkeys 236 - - LAWS AND HYPOTHESES OF BEHAVIOR 241 - - THE EVOLUTION OF THE HUMAN INTELLECT 282 - - - - -ANIMAL INTELLIGENCE - - - - -CHAPTER I - -THE STUDY OF CONSCIOUSNESS AND THE STUDY OF BEHAVIOR - - -The statements about human nature made by psychologists are of two -sorts,—statements about _consciousness_, about the inner life of -thought and feeling, the ‘self as conscious,’ the ‘stream of thought’; -and statements about _behavior_, about the life of man that is left -unexplained by physics, chemistry, anatomy and physiology, and is roughly -compassed for common sense by the terms ‘intellect’ and ‘character.’ - -Animal psychology shows the same double content. Some statements concern -the conscious states of the animal, what he is to himself as an inner -life; others concern his original and acquired ways of response, his -behavior, what he is to an outside observer. - -Of the psychological terms in common use, some refer only to conscious -states, and some refer to behavior regardless of the consciousness -accompanying it; but the majority are ambiguous, referring to the man or -animal in question, at times in his aspect of inner life, at times in his -aspect of reacting organism, and at times as an undefined total nature. -Thus ‘intensity,’ ‘duration’ and ‘quality’ of sensations, ‘transitive’ -and ‘substantive’ states and ‘imagery’ almost inevitably refer to states -of consciousness. ‘Imitation,’ ‘invention’ and ‘practice’ almost -inevitably refer to behavior observed from the outside. ‘Perception,’ -‘attention,’ ‘memory,’ ‘abstraction,’ ‘reasoning’ and ‘will’ are samples -of the many terms which illustrate both ways of studying human and animal -minds. That an animal perceives an object, say, the sun, may mean either -that his mental stream includes an awareness of that object distinguished -from the rest of the visual field; or that he reacts to that object as a -unit. ‘Attention’ may mean a clearness, focalness, of the mental state; -or an exclusiveness and devotion of the total behavior. It may, that -is, be illustrated by the sharpness of objects illumined by a shaft of -light, or by the behavior of a cat toward the bird it stalks. ‘Memory’ -may be consciousness of certain objects, events or facts; or may be -the permanence of certain tendencies in either thought or action. ‘To -recognize’ may be to feel a certain familiarity and surety of being able -to progress to certain judgments about the thing recognized; or may be to -respond to it in certain accustomed and appropriate ways. ‘Abstraction’ -may refer to ideas of qualities apart from any consciousness of their -concrete accompaniments, and to the power of having such ideas; or to -responses to qualities irrespective of their concrete accompaniments, -and to the power of making such responses. ‘Reasoning’ may be said -to be present when certain sorts of consciousness, or when certain -sorts of behavior, are present. An account of ‘the will’ is an account -of consciousness as related to action or an account of the actions -themselves. - -Not only in psychological judgments and psychological terms, but also -in the work of individual psychologists, this twofold content is seen. -Amongst writers in this country, for example, Titchener has busied -himself almost exclusively with consciousness ‘as such’; Stanley Hall, -with behavior; and James, with both. In England Stout, Galton and Lloyd -Morgan have represented the same division and union of interests. - -On the whole, the psychological work of the last quarter of the -nineteenth century emphasized the study of consciousness to the -neglect of the total life of intellect and character. There was a -tendency to an unwise, if not bigoted, attempt to make the science -of human nature synonymous with the science of facts revealed by -introspection. It was, for example, pretended that the only value of all -the measurements of reaction-times was as a means to insight into the -reaction-consciousness,—that the measurements of the amount of objective -difference in the length, brightness or weight of two objects that men -could judge with an assigned degree of correctness were of value only so -far as they allowed one to infer something about the difference between -two corresponding consciousnesses. It was affirmed that experimental -methods were not to aid the experimenter to know what the subject did, -but to aid the subject to know what he experienced. - -The restriction of studies of human intellect and character to studies -of conscious states was not without influence on scientific studies -of animal psychology. For one thing, it probably delayed them. So -long as introspection was lauded as the chief method of psychology, a -psychologist would tend to expect too little from mere studies, from the -outside, of creatures who could not report their inner experiences to -him in the manner to which he was accustomed. In the literature of the -time will be found many comments on the extreme difficulty of studying -the psychology of animals and children. But difficulty exists only in the -case of their _consciousness_. Their _behavior_, by its simpler nature -and causation, is often far easier to study than that of adults. Again, -much time was spent in argumentation about the criteria of consciousness, -that is, about what certain common facts of behavior meant in reference -to inner experience. The problems of inference about consciousness -from behavior distracted attention from the problems of learning more -about behavior itself. Finally, when psychologists began to observe -and experiment upon animal behavior, they tended to overestimate the -resulting insight into the stream of the animal’s thought and to neglect -the direct facts about what he did and how he did it. - -Such observations and experiments are, however, themselves a means of -restoring a proper division of attention between consciousness and -behavior. A psychologist may think of himself as chiefly a stream of -consciousness. He may even think of other men as chiefly conscious -selves whose histories they report by word and deed. But it is only by -an extreme bigotry that he can think of a dog or cat as chiefly a stream -or chain or series of consciousness or consciousnesses. One of the lower -animals is so obviously a bundle of original and acquired connections -between situation and response that the student is led to attend to the -whole series,—situation, response and connection or bond,—rather than -to just the conscious state that may or may not be one of the features -of the bond. It is so useful, in understanding the animal, to see what -it does in different circumstances and what helps and what hinders its -learning, that one is led to an intrinsic interest in varieties of -behavior as well as in the kinds of consciousness of which they give -evidence. - -What each open-minded student of animal psychology at first hand comes -thus to feel vaguely, I propose in this essay to try to make definite -and clear. The studies reprinted in this volume produced in their -author an increased respect for psychology as the science of behavior, a -willingness to make psychology continuous with physiology, and a surety -that to study consciousness for the sake of inferring what a man can or -will do, is as proper as to study behavior for the sake of inferring what -conscious states he can or will have. This essay will attempt to defend -these positions and to show further that psychology may be, at least in -part, as independent of introspection as physics is. - -A psychologist who wishes to broaden the content of the science to -include all that biology includes under the term ‘behavior,’ or all that -common sense means by the words ‘intellect’ and ‘character,’ has to meet -certain objections. The first is the indefiniteness of this content. - -The indefiniteness is a fact, but is not in itself objectionable. It is -true that by an animal’s behavior one means the facts about the animal -that are left over after geometry, physics, chemistry, anatomy and -physiology have taken their toll, and that are not already well looked -after by sociology, economics, history, esthetics and other sciences -dealing with certain complex and specialized facts of behavior. It is -true that the boundaries of psychology, from physiology on the one hand, -and from sociology, economics and the like on the other, become dubious -and changeable. But this is in general a sign of a healthy condition -in a science. The pretense that there is an impassable cleft between -physiology and psychology should arouse suspicion that one or the other -science is studying words rather than realities. - -The same holds against the objection that, if psychology is the science -of behavior, it will be swallowed up by biology. When a body of facts -treated subjectively, vaguely and without quantitative precision by one -science or group of scientists comes to be treated more objectively, -definitely and exactly by another, it is of course a gain, a symptom -of the general advance of science. That geology may become a part of -physics, or physiology a part of chemistry, is testimony to the advance -of geology and physiology. Light is no less worthy of study by being -found to be explainable by laws discovered in the study of electricity. -Meteorology had to reach a relatively high development to provoke the wit -to say that “All the science in meteorology is physics, the rest is wind.” - -These objections to be significant should frankly assert that between -physical facts and mental facts, between bodies and minds, between any -and all of the animal’s movements and its states of consciousness, -there is an impassable gap, a real discontinuity, found nowhere else in -science; and that by making psychology responsible for territory on both -sides of the gap, one makes psychology include two totally disparate -groups of facts, things and thoughts, requiring totally different methods -of study. This is, of course, the traditional view of the scope of -psychology, reiterated in the introductions to the standard books and -often accepted in theory as axiomatic. - -It has, however, already been noted that in practice psychologists do -study facts in disregard of this supposed gap, that the same term refers -to facts belonging some on one side of it and some on the other, and -that, in animal psychology, it seems very unprofitable to try to keep -on one side or the other. Moreover, the practice to which the study of -animal and child psychology leads is, if I understand their writings, -justified as a matter of theory by Dewey and Santayana. If then, as a -matter of scientific fact, human and animal behavior, with or without -consciousness, seems a suitable subject for a scientific student, we may -study it without a too uneasy sense of philosophic heresy and guilt. - -The writer must confess not only to the absence of any special reverence -for the supposed axiom, but also to the presence of a conviction that it -is false, the truth being that whatever feature of any animal, say John -Smith, of _Homo sapiens_, is studied—its length, its color of hair, its -body temperature, its toothache, its anxiety, or its thinking of 9 × -7—the attitude and methods of the student may properly be substantially -the same. - -Of the six facts in the illustration just given, the last three would by -the traditional view be all much alike for study, and all much unlike any -of the first three. The same kind of science, physical science, would be -potent for the first three and impotent for the last three (save to give -facts about certain physical facts which ‘paralleled’ them). Conversely -one kind of science, psychology, would by the traditional view deal with -the last three, but have nothing to say about the first three. - -But is there in actual fact any such radical dichotomy of these six facts -as objects of science? Take any task of science with respect to them, for -example, identification. A score of scientific men, including John Smith -himself, are asked to identify John’s stature at a given moment. Each -observes it carefully, getting, let us say, as measures: 72.10 inches, -72.11, 72.05, 72.08, 72.09, 72.11, etc. - -In the case of color of hair each observes as before, the reports being -brown, light brown, brown, light brown, between light brown and brown, -and so forth. - -In the case of body temperature, again, each observes as before, there -being the same variability in the reports; but John _may also observe -in a second way_, not by observing a thermometer with eyes, but by -observing the temperature of his body through other sense-organs so -situated that they lead to knowledge of only his own body’s temperature. -It is important to note that for efficient knowledge of his own -body-temperature, John does not use the sense approach peculiar to him, -but that available for all observers. He identifies and measures his -‘feverishness’ by studying himself as he would study any other animal, by -thermometer and eye. - -In the case of the toothache the students proceed as before, except -that they use John’s gestures, facial expression, cries and verbal -reports, as well as his mere bodily structure and condition. They not -only observe the cavities in his teeth, the signs of ulcer and the like, -but they also ask him, tapping a tooth, “Does it hurt?” “How long has -it hurt?” “Does it hurt very much?” and the like. John, if their equal -in knowledge of dentistry, would use the same methods, testing himself, -asking himself questions and using the replies made by himself to himself -in inner speech. But, as with temperature, he would get data, for his -identification of the toothache, from a source unavailable for the -others, the sense-organs in his teeth. - -It is worth while to consider how they and he would proceed to an exact -identification or measure of the intensity of his toothache such as was -made of his stature or body-temperature. First, they would need a scale -of toothaches of varying intensities. Next, they would need means of -comparing the intensity of his toothache with those of this scale to see -which it was most like. Given this scale and means of comparison, they -would turn John’s attention from the original toothache to one of given -intensity, and compare the two, both by his facial expression, gestures -and the like, and by the verbal reports made. John would do likewise, -reporting to himself instead of to them. The similarity of the procedure -to that in studying a so-called physical fact is still clearer if we -suppose a primitive condition of the scales of length and temperature. -Suppose for example that for the length of a man we had only ‘short’ or -‘tall as a deer,’ ‘medium’ or ‘tall as a moose,’ and ‘tall’ or ‘tall -as a horse’; and for the intensity of the toothache of a man ‘little’ -or ‘intense as a pin-prick,’ ‘medium’ or ‘intense as a knife-cut,’ -and ‘great’ or ‘intense as a spear-thrust.’ Then obviously the only -difference between the identification of the length of a man’s body and -the identification of the intensity of his toothache would be that the -latter was made by all on the basis of behavior as well as anatomy, and -made by the individual having it on the basis of data from an additional -sense-organ. - -In actual present practice, if observers were asked to identify the -intensity of John’s toothache on a scale running from zero intensity -up, the variability of the reports would be very great in comparison -with those of stature or body-temperature. Supposing the most intense -toothache to be called _K_, we might well have reports of from say .300 -_K_ to .450 _K_, some observers identifying the fact with a condition -one and a half times as intense as that chosen by others. But such a -variability might also occur in primitive men’s judgments of length or -temperature. - -It is important to note that the accuracy of John’s own identification -of it depends in any case on his knowledge of the scale and his power of -comparing his toothache therewith. Well-trained outside observers might -identify the intensity of John’s toothache more accurately than he could. - -In the case of John’s anxiety, the most striking fact is the low degree -of accuracy in identification. The quality of the anxiety and its -intensity would both be so crudely measured by present means that even if -the observers were from the score of most competent psychologists, their -reports would probably be not much better than, say, the descriptions -now found in masterpieces of fiction and drama. Science could not -tell at all closely how much John’s anxiety at this particular time -resembled either his anxiety on some other occasion or anything else. -This inferiority is due in part to the fact that the manifestations -of anxiety in behavior, including verbal reports, are so complicated -by facts other than the anxiety itself, by, for example, the animal’s -health, temperament, concomitant ideas and emotions, knowledge of -language, clearness in expression and the like. It is due in part to -the very low status of our classification of kinds of anxieties and -of our units and scales for measuring the amount of each kind. Hence -the variation amongst observers would be even greater than in the case -of the toothache, and the confidence of all in their judgments would -be less, and far, far less than their confidence in their judgment of -John’s stature. The best possible present knowledge of John’s anxiety, -though scientific in comparison with ordinary opinion about it, would -seem grossly unscientific in comparison with knowledge of his stature or -weight. Knowledge of the anxiety would improve with better knowledge of -its manifestations, including verbal reports by John, and with better -means of classification and measurement. - -John’s knowledge of his own anxiety would be in part the same as that of -the other observers. He too would judge his condition by its external -manifestations, would name its sort and rate its amount on the basis of -his own behavior, as he saw his own face, heard his own groans, and read -the notes he wrote describing his condition. But he would also, as with -the toothache, have data from internal sense-organs and perhaps from -centrally initiated neural actions. In so far as he could report these -data to himself for use in scientific thought more efficiently than he -could report them to the other observers, he would have, as with the -toothache, an advantage comparable to the advantage of a criminologist -who happened also to be or to have been a thief, or of a literary critic -who happened to have written what he judged. It is important to note that -only in so far as he who has ‘immediate experience’ of or participates -in or is ‘directly conscious’ of the anxiety, reports it to himself as -thinker or scientific student, in common with the other nineteen, that -this advantage accrues. To really _be_ or _have_ the anxiety is not to -correctly _know_ it. An insane man must become sane in order to know -his insane condition. Bigotry, stupidity and false reasoning can be -understood only by one who never was them or has ceased to be them. - -In our last illustration, John’s thinking of ‘9 × 7 equals 63,’ the -effect on John’s behavior may be so complicated by other conditions -in John, and is so subject to the particular conditions which we name -John’s ‘will,’ that the observers would often be at loss except for -John’s verbal report. Not that the observer is restricted to that. If -John does the example 217 × 69 in the usual way, it is a very safe -inference that he thought 9 × 7 equals 63, regardless of the absence of a -verbal report from him. But often there is little else to go by. To John -himself, on the contrary, it is easier to be sure that he is thinking -of 9 × 7 equals 63, than that he has a particular sort and strength of -toothache. Consequently if we suppose John to be thinking of that fact -while under observation, and the twenty observers to be required to -identify the fact he is thinking of, it is sure that there might be an -enormous variability in their guesses as to what the fact was and that -his testimony might be worth far more than that of all the other nineteen -without his testimony. His observation is influenced by the action of -the neurones in his central nervous system as theirs is not, and, in the -case of the thought ‘9 × 7 equals 63,’ the action of these neurones is of -special importance. - -Our examination of the way science treats these six facts shows no -impassable cleft between knowledge of a man’s body and knowledge of his -mind. Scientific statements about the toothache, anxiety and numerical -judgment are in general more variable than statements about length, -hair-color and body-temperature, but there is here no difference save of -degree. Some physical facts, such as hair-color, eye-color or health, -are, in fact, judged more variably than some mental facts, such as rate -of adding, accuracy of perception of a certain sort and the like. So -far as the lack of agreement amongst impartial observers goes, there is -continuity from the identification of a length to that of an ideal. - -Scientific judgments about the facts of John’s mind also depend, in -general, more upon his verbal reports than do judgments about his body. -But here also the difference is only of degree. The physician studying -wounds, ulcers, tumors, infections and other facts of a man’s body -may depend more upon his verbal reports than does the moralist who is -studying the man’s character. Verbal reports too are themselves a gradual -and continuous extension of coarser forms of behavior. They signify -consciousness no more truly than do signs, gestures, facial expression -and the general bodily motions of pursuit, retreat, avoidance or seizure. - -Nor is it true that physical facts are known to many observers and mental -facts to but one, who _is_ or _has_ or _directly experiences_ them. If it -were true, sociology, economics, history, anthropology and the like would -either be physical sciences or represent no knowledge at all. The kind of -knowledge of which these sciences and the common judgments of our fellow -men are made up is knowledge possessed by many observers in common, the -individual of whom the facts is known, knowing the fact in part in just -the same way that the others know it. - -The real difference between a man’s scientific judgments about himself -and the judgment of others about him is that he has _added sources of -knowledge_. Much of what goes on in him influences him in ways other -than those in which it influences other men. But this difference is not -coterminous with that between judgments about his ‘mind’ and about his -‘body.’ As was pointed out in the case of body-temperature, a man knows -certain facts about his own body in such additional ways. - -Furthermore, there is no more truth in the statement that a man’s -pain or anxiety or opinions are matters of direct consciousness, pure -experience, than in the statement that his length, weight and temperature -are, or that the sun, moon and stars are. If by the pain we must mean -the pain as felt by some one, then by the sun we can mean only the sun -as seen by some one. Pain and sun are equally subjects for a science of -‘consciousness as such.’ But if by the sun is meant the sun of common -sense, physics and astronomy, the sun as known by any one, then by the -pain we can mean the pain of medicine, economics and sociology, the pain -as known by any one, and by the sufferer long after he _was_ or _had_ it. - -All facts emerge from the matrix of pure experience; but they become -facts for science only after they have emerged therefrom. A man’s anxiety -may be the anxiety as directly felt by the man, or as thought of by him, -or as thought of by the general consensus of scientific observers. But -so also may be his body-temperature or weight or the composition of the -blood in his veins. There can be no valid reason other than a pragmatic -one for studying a man’s anxiety solely as _felt_ by him while studying -his body-temperature as _thought of_ by him and others. And the practical -reasons are all in favor of studying all facts as they exist for any -impartial observer. A man’s mind as it is to thinking men is all that -thinking men can deal with and all that they have any interest in dealing -with. - -Finally, the subject-matter of psychology is not sharply marked off from -the subject-matter of physiology by being absolutely non-spatial. On the -contrary, the toothache, anxiety and judgment are referred unequivocally, -by every sane man who thinks of them, to the space occupied by the body -of the individual in question. That is the surest fact about them. -It is true that we do not measure the length, height, thickness and -weight of an animal’s pain or anxiety, but neither do we those of his -pulse, temperature, health, digestion, metabolism, patellar reflex or -heliotropism. - -Two noteworthy advantages are secured by the study of behavior. First, -the evidence about intellect and character offered by action and the -influence of intellect and character upon action are given due attention. -Second, the connections of conscious states are studied as well as their -composition. - -The mind or soul of the older psychology was the cause not only of -consciousness, but also of modifiability in thought and action. It was -the substance or force in man whereby he was sensitive to certain -events, was able to make certain movements, and not only had ideas but -connected them one with another and with various impressions and acts. -It was supposed to account for actual bodily action as well as for the -action-consciousness. It explained the connections between ideas as well -as their internal composition. If a modern psychologist defines mind -as the sum total of consciousness, and lives up to that definition, he -omits the larger portion of the task of his predecessors. To define our -subject-matter as the nature and behavior of men, beginning where anatomy -and physiology leave off, is, on the contrary, to deliberately assume -responsibility for the entire heritage. Behavior includes consciousness -_and_ action, states of mind _and_ their connections. - -Even students devoted to ‘consciousness as such’ must admit that the -movements of an animal and their connections with other features of -his life deserve study, by even their kind of psychologist. For the -fundamental means of knowing that an animal has a certain conscious -state are knowledge that it makes certain movements and knowledge of -what conscious states are connected with those movements. Knowledge of -the action-system of an animal and its connections is a prerequisite to -knowledge of its stream of consciousness. - -There are better reasons for including the action-system of an animal in -the psychologist’s subject-matter. An animal’s conscious stream is of -no account to the rest of the world except in so far as it prophesies -or modifies his action.[2] There can be no moral warrant for studying -man’s nature unless the study will enable us to control his acts. If -a psychologist is to study man’s consciousness without relation to -movement, he might as well fabricate imaginary consciousnesses to -describe and analyze. The lovers of consciousness for its own sake often -do this unwittingly, but would scarcely take pride therein! - -The truth of the matter is, of course, that an animal’s mind is, by any -definition, something intimately associated with his connection-system -or means of binding various physical activities to various physical -impressions. The whole series—external situations and motor responses as -well as their bonds—must be studied to some extent in order to understand -whatever we define as mind. The student of behavior, by frankly accepting -the task of supplying any needed information not furnished by physiology, -and of studying the animal in action as well as in thought, is surer of -getting an adequate knowledge of whatever features of an animal’s life -may be finally awarded the title of mind. - -The second advantage in studying total behavior rather than consciousness -as such is that thereby the connections of mental facts one with another -and with non-mental facts receive due attention. - -The original tendencies to connect certain thoughts, feelings and acts -with certain situations—tendencies which we call reflexes, instincts -and capacities—are not themselves states of consciousness; nor are -the acquired connections which we call habits, associations of ideas, -tendencies to attend, select and the like. No state of consciousness -bears within itself an account of when and how it will appear, or of -what bodily act will be its sequel. What any given person will think in -any given situation is unpredictable by mere descriptions and analyses -of his previous thoughts each by itself. To understand the _when_, _how_ -and _why_ of states of consciousness one must study other facts than -states of consciousness. These non-conscious relations or connections, -knowledge of which informs us of the result to come from the action of a -given situation on a given animal, may be expected to be fully half of -the subject-matter of mental science. - -As was noted in the early pages of this chapter, the psychologist -commonly does adopt the attitude of treating mind as a system of -connections long enough to give some account of the facts of instinct, -habit, memory, and the like. But the dogma that psychology deals -exclusively with the inner stream of mind-stuff has made these accounts -needlessly scanty and vague. - -One may appreciate fully the importance of finding out whether the -attention-consciousness is clearness or is something else, and whether -it exists in two or three discrete degrees or in a continuous series of -gradations, and still insist upon the equal importance of finding out -to what facts and for what reasons human beings do attend. There would -appear, for example, to be an unfortunate limitation to the study of -human nature by the examination of its consciousnesses, when two eminent -psychologists, writing elaborate accounts of attention from that point of -view, tell us almost nothing whereby we can predict what any given animal -will attend to in any given situation, or can cause in any given animal a -state of attention to any given fact. - -One may enjoy the effort to define the kind of mind-stuff in which one -thinks of classes of facts, relations between facts and judgments about -facts, and still protest that a proper balance in the study of intellect -demands equal or greater attention to the problems of why any given -animal thinks of any given fact, class or relation in any given situation -and why he makes this or that judgment about it. - -In the case of the so-called action-consciousness the neglect of -the connections becomes preposterous. The adventitious scraps of -consciousness called ‘willing’ which may intervene between a situation -productive of a given act and the act itself are hopelessly uninstructive -in comparison with the bonds of instinct and habit which cause the -situation to produce the act. In conduct, at least, that kind of -psychology which Santayana calls ‘the perception of character’ seems an -inevitable part of a well-balanced science of human nature. I quote from -his fine description of the contrast between the external observation -of a mind’s connections and the introspective recapitulation of its -conscious content, though it is perhaps too pronounced and too severe. - -“_Perception of Character._—There is, however, a wholly different and -far more positive method of reading the mind, or what in a metaphorical -sense is called by that name. This method is to read character. Any -object with which we are familiar teaches us to divine its habits; slight -indications, which we should be at a loss to enumerate separately, -betray what changes are going on and what promptings are simmering in -the organism.... The gift of reading character ... is directed not upon -consciousness but upon past or eventual action. Habits and passions, -however, have metaphorical psychic names, names indicating dispositions -rather than particular acts (a disposition being mythically represented -as a sort of wakeful and haunting genius waiting to whisper suggestions -in a man’s ear). We may accordingly delude ourselves into imagining that -a pose or a manner which really indicates habit indicates feeling instead. - -“_Conduct Divined, Consciousness Ignored._... As the weather prophet -reads the heavens, so the man of experience reads other men. Nothing -concerns him less than their consciousness; he can allow that to run -itself off when he is sure of their temper and habits. A great master of -affairs is usually unsympathetic. His observation is not in the least -dramatic or dreamful, he does not yield himself to animal contagion -or reënact other people’s inward experience. He is too busy for that, -and too intent on his own purposes. His observation, on the contrary, -is straight calculation and inference, and it sometimes reaches truths -about people’s character and destiny which they themselves are very far -from divining. Such apprehension is masterful and odious to weaklings, -who think they know themselves because they indulge in copious soliloquy -(which is the discourse of brutes and madmen), but who really know -nothing of their own capacity, situation, or fate.”[3] - -Mr. Santayana elsewhere hints that both psychology and history will -become studies of human behavior considered from without,—a part, that -is, of what he calls physics,—if they are to amount to much. - -Such a prediction may come true. But for the present there is no need -to decide which is better—to study an animal’s self as conscious, its -stream of direct experience, or to study the intellectual and moral -nature that causes its behavior in thought and action and is known to -many observers. Since worthy men have studied both, both are probably -worthy of study. All that I wish to claim is the right of a man of -science to study an animal’s intellectual and moral behavior, following -wherever the facts lead—to “the sum total of human experience considered -as dependent upon the experiencing person,” to the self as conscious, or -to a connection-system known to many observers and born and bred in the -animal’s body. - - - - -CHAPTER II - -ANIMAL INTELLIGENCE; AN EXPERIMENTAL STUDY OF THE ASSOCIATIVE PROCESSES -IN ANIMALS[4] - - -This monograph is an attempt at an explanation of the nature of the -process of association in the animal mind. Inasmuch as there have been no -extended researches of a character similar to the present one either in -subject-matter or experimental method, it is necessary to explain briefly -its standpoint. - -Our knowledge of the mental life of animals equals in the main our -knowledge of their sense-powers, of their instincts or reactions -performed without experience, and of their reactions which are built up -by experience. Confining our attention to the latter, we find it the -opinion of the better observers and analysts that these reactions can -all be explained by the ordinary associative processes without aid from -abstract, conceptual, inferential thinking. These associative processes -then, as present in animals’ minds and as displayed in their acts, are -my subject-matter. Any one familiar in even a general way with the -literature of comparative psychology will recall that this part of the -field has received faulty and unsuccessful treatment. The careful, minute -and solid knowledge of the sense-organs of animals finds no counterpart -in the realm of associations and habits. We do not know how delicate -or how complex or how permanent are the possible associations of any -given group of animals. And although one would be rash who said that our -present equipment of facts about instincts was sufficient or that our -theories about it were surely sound, yet our notion of what occurs when a -chick grabs a worm are luminous and infallible compared to our notion of -what happens when a kitten runs into the house at the familiar call. The -reason that they have satisfied us as well as they have is just that they -are so vague. We say that the kitten associates the sound ‘kitty kitty’ -with the experience of nice milk to drink, which does very well for a -common-sense answer. It also suffices as a rebuke to those who would -have the kitten ratiocinate about the matter, but it fails to tell what -real mental content is present. Does the kitten feel “_sound of call, -memory-image of milk in a saucer in the kitchen, thought of running into -the house, a feeling, finally, of ‘I will run in’_”? Does he perhaps feel -only the sound of the bell and an impulse to run in, similar in quality -to the impulses which make a tennis player run to and fro when playing? -The word ‘association’ may cover a multitude of essentially different -processes, and when a writer attributes anything that an animal may do -to association, his statement has only the negative value of eliminating -reasoning on the one hand and instinct on the other. His position is like -that of a zoölogist who should to-day class an animal among the ‘worms.’ -To give to the word a positive value and several definite possibilities -of meaning is one aim of this investigation. - -The importance to comparative psychology in general of a more scientific -account of the association-process in animals is evident. Apart from the -desirability of knowing all the facts we can, of whatever sort, there -is the especial consideration that these associations and consequent -habits have an immediate import for biological science. In the higher -animals the bodily life and preservative acts are largely directed by -these associations. They, and not instinct, make the animal use the -best feeding grounds, sleep in the same lair, avoid new dangers and -profit by new changes in nature. Their higher development in mammals -is a chief factor in the supremacy of that group. This, however, is a -minor consideration. The main purpose of the study of the animal mind -is to learn the development of mental life down through the phylum, -to trace in particular the origin of human faculty. In relation to -this chief purpose of comparative psychology the associative processes -assume a rôle predominant over that of sense-powers or instinct, for in -a study of the associative processes lies the solution of the problem. -Sense-powers and instincts have changed by addition and supersedence, -but the cognitive side of consciousness has changed not only in quantity -but also in quality. Somehow out of these associative processes have -arisen human consciousnesses with their sciences and arts and religions. -The association of ideas proper, imagination, memory, abstraction, -generalization, judgment, inference, have here their source. And in the -metamorphosis the instincts, impulses, emotions and sense-impressions -have been transformed out of their old natures. For the origin and -development of human faculty we must look to these processes of -association in lower animals. Not only then does this department need -treatment more, but promises to repay the worker better. - -Although no work done in this field is enough like the present -investigation to require an account of its results, the _method_ -hitherto in use invites comparison by its contrast and, as I believe, -by its faults. In the first place, most of the books do not give us a -psychology, but rather a _eulogy_, of animals. They have all been about -animal _intelligence_, never about animal _stupidity_. Though a writer -derides the notion that animals have reason, he hastens to add that -they have marvelous capacity of forming associations, and is likely to -refer to the fact that human beings only rarely reason anything out, -that their trains of ideas are ruled mostly by association, as if, in -this latter, animals were on a par with them. The history of books on -animals’ minds thus furnishes an illustration of the well-nigh universal -tendency in human nature to find the marvelous wherever it can. We wonder -that the stars are so big and so far apart, that the microbes are so -small and so thick together, and for much the same reason wonder at the -things animals do. They used to be wonderful because of the mysterious, -God-given faculty of instinct, which could almost remove mountains. More -lately they have been wondered at because of their marvelous mental -powers in profiting by experience. Now imagine an astronomer tremendously -eager to prove the stars as big as possible, or a bacteriologist whose -great scientific desire is to demonstrate the microbes to be very, very -little! Yet there has been a similar eagerness on the part of many -recent writers on animal psychology to praise the abilities of animals. -It cannot help leading to partiality in deductions from facts and more -especially in the choice of facts for investigation. How can scientists -who write like lawyers, defending animals against the charge of having no -power of rationality, be at the same time impartial judges on the bench? -Unfortunately the real work in this field has been done in this spirit. -The level-headed thinkers who might have won valuable results have -contented themselves with arguing against the theories of the eulogists. -They have not made investigations of their own. - -In the second place, the facts have generally been derived from -anecdotes. Now quite apart from such pedantry as insists that a man’s -word about a scientific fact is worthless unless he is a trained -scientist, there are really in this field special objections to the -acceptance of the testimony about animals’ intelligent acts which -one gets from anecdotes. Such testimony is by no means on a par with -testimony about the size of a fish or the migration of birds, etc. For -here one has to deal not merely with ignorant or inaccurate testimony, -but also with prejudiced testimony. Human folk are as a matter of fact -eager to find intelligence in animals. They like to. And when the animal -observed is a pet belonging to them or their friends, or when the story -is one that has been told as a story to entertain, further complications -are introduced. Nor is this all. Besides commonly misstating what -facts they report, they report only such facts as show the animal at -his best. Dogs get lost hundreds of times and no one ever notices it -or sends an account of it to a scientific magazine. But let one find -his way from Brooklyn to Yonkers and the fact immediately becomes a -circulating anecdote. Thousands of cats on thousands of occasions sit -helplessly yowling, and no one takes thought of it or writes to his -friend, the professor; but let one cat claw at the knob of a door -supposedly as a signal to be let out, and straightway this cat becomes -the representative of the cat-mind in all the books. The unconscious -distortion of the facts is almost harmless compared to the unconscious -neglect of an animal’s mental life until it verges on the unusual and -marvelous. It is as if some denizen of a planet where communication -was by thought-transference, who was surveying humankind and reporting -their psychology, should be oblivious to all our intercommunication -save such as the psychical-research society has noted. If he should -further misinterpret the cases of mere coincidence of thoughts as facts -comparable to telepathic communication, he would not be more wrong than -some of the animal psychologists. In short, the anecdotes give really the -_abnormal_ or _supernormal_ psychology of animals. - -Further, it must be confessed that these vices have been only -ameliorated, not obliterated, when the observation is first-hand, is -made by the psychologist himself. For as men of the utmost scientific -skill have failed to prove good observers in the field of spiritualistic -phenomena,[5] so biologists and psychologists before the pet terrier or -hunted fox often become like Samson shorn. They, too, have looked for the -intelligent and unusual and neglected the stupid and normal. - -Finally, in all cases, whether of direct observation or report by good -observers or bad, there have been three other defects. Only a single -case is studied, and so the results are not necessarily true of the -type; the observation is not repeated, nor are the conditions perfectly -regulated; the previous history of the animal in question is not known. -Such observations may tell us, if the observer is perfectly reliable, -that a certain thing takes place; but they cannot assure us that it will -take place universally among the animals of that species, or universally -with the same animal. Nor can the influence of previous experience be -estimated. All this refers to means of getting knowledge about what -animals _do_. The next question is, “What do they _feel_?” Previous work -has not furnished an answer or the material for an answer to this more -important question. Nothing but carefully designed, crucial experiments -can. In abandoning the old method one ought to seek above all to replace -it by one which will not only tell more accurately _what they do_, and -give the much-needed information _how they do it_, but also inform us -_what they feel_ while they act. - -To remedy these defects, experiment must be substituted for observation -and the collection of anecdotes. Thus you immediately get rid of several -of them. You can repeat the conditions at will, so as to see whether -or not the animal’s behavior is due to mere coincidence. A number of -animals can be subjected to the same test, so as to attain typical -results. The animal may be put in situations where its conduct is -especially instructive. After considerable preliminary observation of -animals’ behavior under various conditions, I chose for my general method -one which, simple as it is, possesses several other marked advantages -besides those which accompany experiment of any sort. It was merely to -put animals when hungry in inclosures from which they could escape by -some simple act, such as pulling at a loop of cord, pressing a lever, -or stepping on a platform. (A detailed description of these boxes and -pens will be given later.) The animal was put in the inclosure, food was -left outside in sight, and his actions observed. Besides recording his -general behavior, special notice was taken of how he succeeded in doing -the necessary act (in case he did succeed), and a record was kept of the -time that he was in the box before performing the successful pull, or -clawing, or bite. This was repeated until the animal had formed a perfect -association between the sense-impression of the interior of that box and -the impulse leading to the successful movement. When the association -was thus perfect, the time taken to escape was, of course, practically -constant and very short. - -If, on the other hand, after a certain time the animal did not succeed, -he was taken out, but _not fed_. If, after a sufficient number of -trials, he failed to get out, the case was recorded as one of complete -failure. Enough different sorts of methods of escape were tried to -make it fairly sure that association in general, not association of a -particular sort of impulse, was being studied. Enough animals were taken -with each box or pen to make it sure that the results were not due to -individual peculiarities. None of the animals used had any previous -acquaintance with any of the mechanical contrivances by which the doors -were opened. So far as possible the animals were kept in a uniform state -of hunger, which was practically utter hunger.[6] That is, no cat or dog -was experimented on, when the experiment involved any important question -of fact or theory, unless I was sure that his motive was of the standard -strength. With chicks this is not practicable, on account of their -delicacy. But with them dislike of loneliness acts as a uniform motive to -get back to the other chicks. Cats (or rather kittens), dogs and chicks -were the subjects of the experiments. All were apparently in excellent -health, save an occasional chick. - -By this method of experimentation the animals are put in situations which -call into activity their mental functions and permit them to be carefully -observed. One may, by following it, observe personally more intelligent -acts than are included in any anecdotal collection. And this actual -vision of animals in the act of using their minds is far more fruitful -than any amount of history of what animals have done without the history -of how they did it. But besides affording this opportunity for purposeful -and systematic observation, our method is valuable because it frees the -animal from any influence of the observer. The animal’s behavior is -quite independent of any factors save its own hunger, the mechanism of -the box it is in, the food outside, and such general matters as fatigue, -indisposition, etc. Therefore the work done by one investigator may be -repeated and verified or modified by another. No personal factor is -present save in the observation and interpretation. Again, our method -gives some very important results which are quite uninfluenced by -_any_ personal factor in any way. The curves showing the progress of -the formation of associations, which are obtained from the records of -the times taken by the animal in successive trials, are facts which -may be obtained by any observer who can tell time. They are absolute, -and whatever can be deduced from them is sure. So also the question of -whether an animal does or does not form a certain association requires -for an answer no higher qualification in the observer than a pair of -eyes. The literature of animal psychology shows so uniformly and often so -sadly the influence of the personal equation that any method which can -partially eliminate it deserves a trial. - -Furthermore, although the associations formed are such as could not -have been previously experienced or provided for by heredity, they are -still not too remote from the animal’s ordinary course of life. They -mean simply the connection of a certain act with a certain situation -and resultant pleasure, and this general type of association is found -throughout the animal’s life normally. The muscular movements required -are all such as might often be required of the animal. And yet it will -be noted that the acts required are nearly enough like the acts of the -anecdotes to enable one to compare the results of experiment by this -method with the work of the anecdote school. Finally, it may be noticed -that the method lends itself readily to experiments on imitation. - -We may now start in with the description of the apparatus and of the -behavior of the animals.[7] - - -DESCRIPTION OF APPARATUS - -[Illustration: FIG. 1.] - -The shape and general apparatus of the boxes which were used for the cats -is shown by the accompanying drawing of box K. Unless special figures -are given, it should be understood that each box is approximately 20 -inches long, by 15 broad, by 12 high. Except where mention is made to -the contrary, the door was pulled open by a weight attached to a string -which ran over a pulley and was fastened to the door, just as soon as -the animal loosened the bolt or bar which held it. Especial care was -taken not to have the widest openings between the bars at all near the -lever, or wire loop, or what not, which governed the bolt on the door. -For the animal instinctively attacks the large openings first, and if -the mechanism which governs the opening of the door is situated near one -of them, the animal’s task is rendered easier. You do not then get the -association-process so free from the helping hand of instinct as you do -if you make the box without reference to the position of the mechanism to -be set up within it. These various mechanisms are so simple that a verbal -description will suffice in most cases. The facts which the reader should -note are the nature of the movement which the cat had to make, the nature -of the object at which the movement was directed, and the position of the -object in the box. In some special cases attention will also be called -to the force required. In general, however, that was very slight (20 to -100 grams if applied directly). The various boxes will be designated by -capital letters. - -A. A string attached to the bolt which held the door ran up over a pulley -on the front edge of the box, and was tied to a wire loop (2½ inches -in diameter) hanging 6 inches above the floor in front center of box. -Clawing or biting it, or rubbing against it even, if in a certain way, -opened the door. We may call this box A ‘_O at front_.’ - -B. A string attached to the bolt ran up over a pulley on the front edge -of the door, then across the box to another pulley screwed into the -inside of the back of the box 1¼ inches below the top, and passing over -it ended in a wire loop (3 inches in diameter) 6 inches above the floor -in back center of box. Force applied to the loop or _to the string_ as it -ran across the top of the box between two bars would open the door. We -may call B ‘_O at back_.’ - -B1. In B1 the string ran outside the box, coming down through a hole at -the back, and was therefore inaccessible and invisible from within. Only -by pulling the loop could the door be opened. B1 may be called ‘_O at -back 2d_.’ - -C. A door of the usual position and size (as in Fig. 1) was kept closed -by a wooden button 3½ inches long, ⅞ inch wide, ½ inch thick. This turned -on a nail driven into the box ½ inch above the middle of the top edge of -the door. The door would fall inward as soon as the button was turned -from its vertical to a horizontal position. A pull of 125 grams would -do this if applied sideways at the lowest point of the button 2¼ inches -below its pivot. The cats usually clawed the button round by downward -pressure on its top edge, which was 1¼ inches above the nail. Then, of -course, more force was necessary. C may be called ‘_Button_.’ - -D. The door was in the extreme right of the front. A string fastened to -the bolt which held it ran up over a pulley on the top edge and back to -the top edge of the back side of the box (3 inches in from the right -side) and was there firmly fastened. The top of the box was of wire -screening and arched over the string ¾ inch above it along its entire -length. A slight pull on the string anywhere opened the door. This box -was 20 × 16, but a space 7 × 16 was partitioned off at the left by a wire -screen. D may be called ‘_String_.’ - -D1 was the same box as B, but had the string fastened firmly at the back -instead of running over a pulley and ending in a wire loop. We may call -it ‘_String 2d_.’ - -E. A string ran from the bolt holding the door up over a pulley and down -to the floor outside the box, where it was fastened 2 inches in front of -the box and 1½ inches to the left of the door (looking from the inside). -By poking a paw out between the bars and pulling this string inward the -door would be opened. We may call E ‘_String outside_.’ - -In F the string was not fastened to the floor but ended in a loop 2½ -inches in diameter which could be clawed down so as to open the door. -Unless the pull was in just the right direction, the string was likely -to catch on the pulley. This loop hung 3 inches above the floor, and 1¾ -inches in front of the box. We may call F ‘_String outside unfastened_.’ - -G was a box 29 × 20½ × 22½, with a door 29 × 12 hinged on the left side -of the box (looking from within), and kept closed by an ordinary thumb -latch placed 15 inches from the floor. The remainder of the front of the -box was closed in by wooden bars. The door was a wooden frame covered -with screening. It was _not_ arranged so as to open as soon as the latch -was lifted, but required a force of 400 grams, even when applied to the -best advantage. The bar of the thumb latch, moreover, would fall back -into place again unless the door were pushed out at least a little. The -top of this box was not of bars or screening, but solid. We may call G -‘_Thumb latch_.’ - -H was, except for the opening where the door was situated, a perfectly -solid and dark box. In the front was cut an opening about 9 × 7 inches. -A wooden frame covered with wire netting hung in front of this. It was -fastened to the box only by a screw through the middle of the frame’s -top piece, and could therefore be pushed to either side so as to permit -escape from the box if it were prevented from swinging back into place. - -I was a box 12 × 14 × 23. The door was 8 inches wide, 4 high, and hinged -at the left side. It was held closed by a wooden bar which moved easily -on a pivot and which could be pushed up by another bar which projected -5 inches into the box. This second bar was pivoted so that downward -pressure on it pushed the first bar up and let the door swing open. The -second bar entered the box at a point 4 inches above the floor and 2½ -inches in from the right side of the box. In its normal position its -inner end was 5½ inches above the floor. A depression of 2 inches at that -end was necessary to open the door. Of course, nearer the pivot a shorter -depression would do. The front of the box was closed by bars, but the -rest by solid boards. We may call I ‘_Lever_.’ - -J was the same as B except that the door was not opened by a weight as -soon as the bolt was pulled up. On the contrary, the door was held closed -by a small piece of board (4 × 3½ × ¾ thick) placed against it outside. -After pulling the loop at the back the cat had to knock down this support -and push the door open. We may call J ‘_Double_.’ - -K was a box arranged so that three separate acts were required to open -the door, which was held by two bolts at the top and two bars outside. -One of the bolts was connected with a platform in the back center of the -box so that depressing the platform raised the bolt. The other was raised -by a string which ran up over a pulley in the front, across the box 1 -inch above the bars, over a pulley near the corner of the box, and down -to the floor, where it was fastened. Pulling on this string, either by -clawing at it where it was running vertically from the last pulley to the -floor, or by putting the paw out between the bars which covered the top -of the box, and clawing the string downward, would raise the bolt. If -both bolts were raised and _either_ bar was pushed up or down far enough -to be out of the way, the cat could escape. K, or ‘_Triple_,’ as it may -be called, is the box reproduced in Figure 1. - -L was a box that also required three acts to open the door. It was a -combination of A (O at front), D (string), I (lever). The lever or bar -to be depressed was 2 inches to the right of the door, which was in the -front center. The string to be clawed or bitten ran from front center to -back center 1 inch below the top of the box. - -Z was a box with back and sides entirely closed, with front and top -closed by bars and screening, with a small opening in the left-hand -corner. A box was held in front of this and drawn away when the cats -happened to lick themselves. Thus escape and food followed always upon -the impulse to lick themselves, and they soon would immediately start -doing so as soon as pushed into the box. The same box was used with the -impulse changed to that for scratching themselves. The size of this box -was 15 × 10 × 16. - - -EXPERIMENTS WITH CATS - -In these various boxes were put cats from among the following. I give -approximately their ages while under experiment. - - No. 1. 8-10 months. - No. 2. 5-7 months. - No. 3. 5-11 months. - No. 4. 5-8 months. - No. 5. 5-7 months. - No. 6. 3-5 months. - No. 7. 3-5 months. - No. 8. 6-6½ months. - No. 10. 4-8 months. - No. 11. 7-8 months. - No. 12. 4-6 months. - No. 13. 18-19 months. - -The behavior of all but 11 and 13 was practically the same. When put into -the box the cat would show evident signs of discomfort and of an impulse -to escape from confinement. It tries to squeeze through any opening; it -claws and bites at the bars or wire; it thrusts its paws out through any -opening and claws at everything it reaches; it continues its efforts -when it strikes anything loose and shaky; it may claw at things within -the box. It does not pay very much attention to the food outside, but -seems simply to strive instinctively to escape from confinement. The -vigor with which it struggles is extraordinary. For eight or ten minutes -it will claw and bite and squeeze incessantly. With 13, an old cat, and -11, an uncommonly sluggish cat, the behavior was different. They did not -struggle vigorously or continually. On some occasions they did not even -struggle at all. It was therefore necessary to let them out of some box -a few times, feeding them each time. After they thus associate climbing -out of the box with getting food, they will try to get out whenever put -in. They do not, even then, struggle so vigorously or get so excited -as the rest. In either case, whether the impulse to struggle be due -to an instinctive reaction to confinement or to an association, it is -likely to succeed in letting the cat out of the box. The cat that is -clawing all over the box in her impulsive struggle will probably claw -the string or loop or button so as to open the door. And gradually all -the other non-successful impulses will be stamped out and the particular -impulse leading to the successful act will be stamped in by the resulting -pleasure, until, after many trials, the cat will, when put in the box, -immediately claw the button or loop in a definite way. - -The starting point for the formation of any association in these cases, -then, is the set of instinctive activities which are aroused when a cat -feels discomfort in the box either because of confinement or a desire -for food. This discomfort, plus the sense-impression of a surrounding, -confining wall, expresses itself, prior to any experience, in squeezings, -clawings, bitings, etc. From among these movements one is selected by -success. But this is the starting point only in the case of the first -box experienced. After that the cat has associated with the feeling of -confinement certain impulses which have led to success more than others -and are thereby strengthened. A cat that has learned to escape from A by -clawing has, when put into C or G, a greater tendency to claw at things -than it instinctively had at the start, and a less tendency to squeeze -through holes. A very pleasant form of this decrease in instinctive -impulses was noticed in the gradual cessation of howling and mewing. -However, the useless instinctive impulses die out slowly, and often play -an important part even after the cat has had experience with six or eight -boxes. And what is important in our previous statement, namely, that -the activity of an animal when first put into a new box is not directed -by any appreciation of _that_ box’s character, but by certain general -impulses to act, is not affected by this modification. Most of this -activity is determined by heredity; some of it, by previous experience. - -My use of the words _instinctive_ and _impulse_ may cause some -misunderstanding unless explained here. Let us, throughout this -book, understand by instinct any reaction which an animal makes to a -situation _without experience_. It thus includes unconscious as well as -conscious acts. Any reaction, then, to totally new phenomena, when first -experienced, will be called instinctive. Any impulse then felt will be -called an instinctive impulse. Instincts include whatever the nervous -system of an animal, as far as inherited, is capable of. My use of the -word will, I hope, everywhere make clear what fact I mean. If the reader -gets the fact meant in mind it does not in the least matter whether he -would himself call such a fact instinct or not. Any one who objects to -the word may substitute ‘hocus-pocus’ for it wherever it occurs. The -definition here made will not be used to prove or disprove any theory, -but simply as a signal for the reader to imagine a certain sort of fact. - -The word _impulse_ is used against the writer’s will, but there is no -better. Its meaning will probably become clear as the reader finds it in -actual use, but to avoid misconception at any time I will state now that -_impulse_ means the consciousness accompanying a muscular innervation -_apart from that feeling of the act which comes from seeing oneself -move, from feeling one’s body in a different position, etc._ It is the -_direct feeling of the doing_ as distinguished from the _idea of the -act done_ gained through eye, etc. For this reason I say ‘impulse _and_ -act’ instead of simply ‘act.’ Above all, it must be borne in mind that -by impulse I never mean the _motive_ to the act. In popular speech you -may say that hunger is the impulse which makes the cat claw. That will -never be the use here. The word _motive_ will always denote that sort -of consciousness. Any one who thinks that the act ought not to be thus -subdivided into impulse and deed may feel free to use the word _act_ for -_impulse_ or _impulse and act_ throughout, if he will remember that the -act in this aspect of being felt as to be done or as doing is in animals -the important thing, is the thing which gets associated, while the act as -done, as viewed from outside, is a secondary affair. I prefer to have a -separate word, _impulse_, for the former, and keep the word _act_ for the -latter, which it commonly means. - -Starting, then, with its store of instinctive impulses, the cat hits -upon the successful movement, and gradually associates it with the -sense-impression of the interior of the box until the connection is -perfect, so that it performs the act as soon as confronted with the -sense-impression. The formation of each association may be represented -graphically by a time-curve. In these curves lengths of one millimeter -along the abscissa represent successive experiences in the box, and -heights of one millimeter above it each represent ten seconds of time. -The curve is formed by joining the tops of perpendiculars erected along -the abscissa 1 mm. apart (the first perpendicular coinciding with the -_y_ line), each perpendicular representing the time the cat was in the -box before escaping. Thus, in Fig. 2 on page 39 the curve marked _12 in -A_ shows that, in 24 experiences or trials in box A, cat 12 took the -following times to perform the act, 160 sec., 30 sec., 90 sec., 60, 15, -28, 20, 30, 22, 11, 15, 20, 12, 10, 14, 10, 8, 8, 5, 10, 8, 6, 6, 7. -A short vertical line below the abscissa denotes that an interval of -approximately 24 hours elapsed before the next trial. Where the interval -was longer it is designated by a figure 2 for two days, 3 for three days, -etc. If the interval was shorter, the number of hours is specified by -1 hr., 2 hrs., etc. In many cases the animal failed in some trial to -perform the act in ten or fifteen minutes and was then taken out by me. -Such failures are denoted by a break in the curve either at its start or -along its course. In some cases there are short curves after the main -ones. These, as shown by the figures beneath, represent the animal’s -mastery of the association after a very long interval of time, and may be -called memory-curves. A discussion of them will come in the last part of -the chapter. - -[Illustration: FIG. 2.] - -The time-curve is obviously a fair representation of the progress of -the formation of the association, for the two essential factors in the -latter are the disappearance of all activity save the particular sort -which brings success with it, and perfection of that particular sort of -act so that it is done precisely and at will. Of these the second is, on -deeper analysis, found to be a part of the first; any clawing at a loop -except the particular claw which depresses it is theoretically a useless -activity. If we stick to the looser phraseology, however, no harm will -be done. The combination of these two factors is inversely proportional -to the time taken, provided the animal surely wants to get out at once. -This was rendered almost certain by the degree of hunger. Theoretically -a perfect association is formed when both factors are perfect,—when the -animal, for example, does nothing but claw at the loop, and claws at it -in the most useful way for the purpose. In some cases (_e.g._ 2 in K on -page 53) neither factor ever gets perfected in a great many trials. In -some cases the first factor does but the second does not, and the cat -goes at the thing not always in the desirable way. In all cases there is -a fraction of the time which represents getting oneself together after -being dropped in the box, and realizing where one is. But for our purpose -all these matters count little, and we may take the general slope of the -curve as representing very fairly the progress of the association. The -slope of any particular part of it may be due to accident. Thus, very -often the second experience may have a higher time-point than the first, -because the first few successes may all be entirely due to accidentally -hitting the loop, or whatever it is, and whether the accident will -happen sooner in one trial than another is then a matter of chance. -Considering the general slope, it is, of course, apparent that a gradual -descent—say, from initial times of 300 sec. to a constant time of 6 or 8 -sec. in the course of 20 to 30 trials—represents a difficult association; -while an abrupt descent, say in 5 trials, from a similar initial height, -represents a very easy association. Thus, 2 in Z, on page 57, is a hard, -and 1 in I, on page 49, an easy association. - -[Illustration: FIG. 3.] - -In boxes A, C, D, E, I, 100 per cent of the cats given a chance to do so, -hit upon the movement and formed the association. The following table -shows the results where some cats failed:— - - -TABLE 1 - - NO. CATS TRIED NO. CATS FAILED - +---------------+---------------+ - F | 5 | 4 | - G | 8 | 5 | - H | 9 | 2 | - J | 5 | 2 | - K | 5 | 2 | - +---------------+---------------+ - -The time-curves follow. By referring to the description of apparatus they -will be easily understood. Each mm. along the abscissa represents one -trial. Each mm. above it represents 10 seconds. - -[Illustration: FIG. 4.] - -[Illustration: FIG. 5.] - -These time-curves show, in the first place, what associations are easy -for an animal to form, and what are hard. The act must be one which the -animal will perform in the course of the activity which its inherited -equipment incites or its previous experience has connected with the -sense-impression of a box’s interior. The oftener the act naturally -occurs in the course of such activity, the sooner it will be performed -in the first trial or so, and this is one condition, sometimes, of the -ease of forming the association. For if the first few successes are five -minutes apart, the influence of one may nearly wear off before the next, -while if they are forty seconds apart the influences may get summated. -But this is not the only or the main condition of the celerity with which -an association may be formed. It depends also on the amount of attention -given to the act. An act of the sort likely to be well attended to will -be learned more quickly. Here, too, accident may play a part, for a cat -may merely happen to be attending to its paw when it claws. The kind of -acts which insure attention are those where the movement which works the -mechanism is one which the cat makes definitely to get out. Thus A (O -at front) is easier to learn than C (button), because the cat does A in -trying to claw down the front of the box and so is attending to what it -does; whereas it does C generally in a vague scramble along the front -or while trying to claw outside with the other paw, and so does not -attend to the little unimportant part of its act which turns the button -round. Above all, _simplicity_ and _definiteness_ in the act make the -association easy. G (thumb latch), J (double) and K and L (triples) are -hard, because complex. E is easy, because directly in the line of the -instinctive impulse to try to pull oneself out of the box by clawing at -anything outside. It is thus very closely attended to. The extreme of -ease is reached when a single experience stamps the association in so -completely that ever after the act is done at once. This is approached in -I and E. - -[Illustration: FIG. 6.] - -In these experiments the sense-impressions offered no difficulty one more -than the other. - -Vigor, abundance of movements, was observed to make differences between -individuals in the same association. It works by shortening the first -times, the times when the cat still does the act largely by accident. -Nos. 3 and 4 show this throughout. Attention, often correlated with lack -of vigor, makes a cat form an association more quickly after he gets -started. No. 13 shows this somewhat. The absence of a fury of activity -let him be more conscious of what he did do. - -[Illustration: FIG. 7.] - -The curves on pages 57 and 58, showing the history of cats 1, 5, 13 and -3, which were let out of the box Z when they licked themselves, and of -cats 6, 2 and 4, which were let out when they scratched themselves, are -interesting because they show associations where there is no congruity -(no more to a cat than to a man) between the act and the result. One -chick, too, was thus freed whenever he pecked at his feathers to dress -them. He formed the association, and would whirl his head round and poke -it into his feathers as soon as dropped in the box. There is in all these -cases a noticeable tendency, of the cause of which I am ignorant, to -diminish the act until it becomes a mere vestige of a lick or scratch. -After the cat gets so that it performs the act soon after being put in, -it begins to do it less and less vigorously. The licking degenerates into -a mere quick turn of the head with one or two motions up and down with -tongue extended. Instead of a hearty scratch, the cat waves its paw up -and down rapidly for an instant. Moreover, if sometimes you do not let -the cat out after this feeble reaction, it does not at once repeat the -movement, as it would do if it depressed a thumb piece, for instance, -without success in getting the door open. Of the reason for this -difference I am again ignorant. - -Previous experience makes a difference in the quickness with which the -cat forms the associations. After getting out of six or eight boxes by -different sorts of acts the cat’s general tendency to claw at loose -objects within the box is strengthened and its tendency to squeeze -through holes and bite bars is weakened; accordingly it will learn -associations along the general line of the old more quickly. Further, -its tendency to pay attention to what it is doing gets strengthened, -and this is something which may properly be called a change in degree -of intelligence. A test was made of the influence of experience in this -latter way by putting two groups of cats through I (lever), one group (1, -2, 3, 4, 5) after considerable experience, the other (10, 11, 12) after -experience with only one box. As the act in I was not along the line -of the acts in previous boxes, and as a decrease in the squeezings and -bitings would be of little use in the box as arranged, the influence of -experience in the former way was of little account. The curves of all are -shown on page 49. - -[Illustration: FIG. 8.] - -If the whole set of curves are examined in connection with the following -table, which gives the general order in which each animal took up the -different associations which he eventually formed, many suggestions -of the influence of experience will be met with. The results are not -exhaustive enough to justify more than the general conclusion that there -is such an influence. By taking more individuals and thus eliminating all -other factors besides experience, one can easily show just how and how -far experience facilitates association. - -When, in this table, the letters designating the boxes are in italics it -means that, though the cat formed the association, it was in connection -with other experiments and so is not recorded in the curves. - - -TABLE 2 - - +------+-------------------------------+ - |Cat 1 | _A_ _B_ _C_ _D₁_ _D_ Z I | - |Cat 2 | _C_ _D₁_ _D_ E Z H J I K | - |Cat 3 | A C E G H J Z I K | - |Cat 4 | C F G D Z H J I K | - |Cat 5 | C E Z H I | - |Cat 6 | _A_ _C_ E Z | - |Cat 7 | _A_ _C_ | - |Cat 10| C I A H D L | - |Cat 11| C I A H D L | - |Cat 12| C I A H D L | - |Cat 13| A C D G Z | - +------+-------------------------------+ - -[Illustration: FIG. 9.] - -The advantage due to experience in our experiments is not, however, -the same as ordinarily in the case of trained animals. With them the -associations are with the acts or voice of man or with sense-impressions -to which they naturally do not attend (_e.g._ figures on a blackboard, -ringing of a bell, some act of another animal). Here the advantage of -experience is mainly due to the fact that by such experience the animals -gain the habit of attending to the master’s face and voice and acts and -to sense-impressions in general. - -I made no attempt to find the differences in ability to acquire -associations due to age or sex or fatigue or circumstances of any -sort. By simply finding the average slope in the different cases to be -compared, one can easily demonstrate any such differences that exist. So -far as this discovery is profitable, investigation along this line ought -now to go on without delay, the method being made clear. Of differences -due to differences in the species, genus, etc., of the animals I will -speak after reviewing the time-curves of dogs and chicks. - -In the present state of animal psychology there is another value to -these results which was especially aimed at by the investigator from the -start. They furnish a quantitative estimate of what the average cat can -do, so that if any one has an animal which he thinks has shown superior -intelligence or perhaps reasoning power, he may test his observations and -opinion by taking the time-curves of the animal in such boxes as I have -described. - -[Illustration: FIG. 10.] - -If his animal in a number of cases forms the associations very much more -quickly, or deals with the situation in a more intelligent fashion than -my cats did, then he may have ground for claiming in his individual a -variation toward greater intelligence and, possibly, intelligence of a -different order. On the other hand, if the animal fails to rise above the -type in his dealings with the boxes, the observer should confess that his -opinion of the animal’s intelligence may have been at fault and should -look for a correction of it. - -We have in these time-curves a fairly adequate measure of what the -ordinary cat can do, and how it does it, and in similar curves soon to -be presented a less adequate measure of what a dog may do. If other -investigators, especially all amateurs who are interested in animal -intelligence, will take other cats and dogs, especially those supposed -by owners to be extraordinarily intelligent, and experiment with them in -this way, we shall soon get a notion of how much variation there is among -animals in the direction of more or superior intelligence. The beginning -here made is meager but solid. The knowledge it gives needs to be much -extended. The variations found in individuals should be correlated, not -merely with supposed superiority in intelligence, a factor too vague to -be very serviceable, but with observed differences in vigor, attention, -memory and muscular skill. No phenomena are more capable of exact and -thorough investigation by experiment than the associations of animal -consciousness. Never will you get a better psychological subject than a -hungry cat. When the crude beginnings of this research have been improved -and replaced by more ingenious and adroit experimenters, the results -ought to be very valuable. - -Surely every one must agree that no man now has a right to advance -theories about what is in animals’ minds or to deny previous theories -unless he supports his thesis by systematic and extended experiments. My -own theories, soon to be proclaimed, will doubtless be opposed by many. -I sincerely hope they will, provided the denial is accompanied by actual -experimental work. In fact, I shall be tempted again and again in the -course of this book to defend some theory, dubious enough to my own mind, -in the hope of thereby inducing some one to oppose me and in opposing me -to make the experiments I have myself had no opportunity to make yet. -Probably there will be enough opposition if I confine myself to the -theories I feel sure of. - -[Illustration: FIG. 11.] - - -EXPERIMENTS WITH DOGS - -The boxes used were as follows: - -AA was similar to A (O at front), except that the loop was of stiff cord -⅜ inch in diameter and was larger (3½ inches diameter); also it was hung -a foot from the floor and 8 inches to the right of the door. The box -itself was 41 × 20 × 23. - -BB was similar to B, the loop being the same as in AA, and being hung a -foot from the floor. The box was of the same size and shape as AA. - -BB1 was like BB, but the loop was hung 18 inches from the floor. - -CC was similar to C (button), but the button was 6 inches long, and the -box was 36½ × 22 × 23. - -II was similar to I, but the box was 30 × 20 × 25 inches; the door (11 -inches wide, 6 high) was in the left front corner, and the lever was 6 -inches long and entered the box at a point 2 inches to the right of the -door and 4 inches above the floor. - -[Illustration: FIG. 12.] - -In M the same box as in II was used, but instead of a lever projecting -inside the box, a lever running outside parallel to the plane of the -front of the box and 18 inches long was used. This lay close against the -bars composing the front of the box, and could be pawed down by sticking -the paw out an inch or so between two bars, at a point about 15 inches -high and 6 inches in from the right edge of the front. We may call M -‘_Lever outside_.’ - -[Illustration: FIG. 13.] - -N was a pen 5 × 3 feet made of wire netting 46 inches high. The door, 31 -× 20, was in the right half of the front. A string from the bolt passed -up over a pulley and back to the back center, where it was fastened 33 -inches above the floor. Biting or pawing this string opened the door. - -O was like K, except that there was only one bar, that the string ran -inside the box, so that it was easily accessible, and that the bolt -raised in K by depression of the platform could be raised in O (and was -by the dog experimented on) by sticking the muzzle out between two bars -just above the bolt and by biting the string, at the same time jerking it -upward. O was 30 × 20 × 25 in size. - -The box G was used for both dogs and cats, without any variation save -that for dogs the resistance of the door to pressure outwards was doubled. - -In these boxes were put in the course of the experiments dog 1 (about 8 -months old), and dogs 2 and 3, adults, all of small size. - -A dog who, when hungry, is shut up in one of these boxes is not nearly -so vigorous in his struggles to get out as is the young cat. And even -after he has experienced the pleasure of eating on escape many times he -does not try to get out so hard as a cat, young or old. He does try to -a certain extent. He paws or bites the bars or screening, and tries to -squeeze out in a tame sort of way. He gives up his attempts sooner than -the cat, if they prove unsuccessful. Furthermore his attention is taken -by the food, not the confinement. He wants to get _to_ the food, not _out -of_ the box. So, unlike the cat, he confines his efforts to the front -of the box. It was also a practical necessity that the dogs should be -kept from howling in the evening, and for this reason I could not use -as motive the utter hunger which the cats were made to suffer. In the -morning, when the experiments were made, the dogs were surely hungry, -and no experiment is recorded in which the dog was not in a state to be -willing to make a great effort for a bit of meat, but the motive may not -have been even and equal throughout, as it was with the cats. - -[Illustration: FIG. 14.] - -The curves on page 60 are to be interpreted in the same way as those for -the cats, and are on the same scale. The order in which No. 1 took up the -various associations was AA, BB, BB1, G, N, CC, II, O. - -The percentage of dogs succeeding in the various boxes is given below, -but is of no consequence, because so few were tried, and because the -motive, hunger, was not perhaps strong enough, or equal in all cases. - -In AA 3 out of 3. - -In BB 0 out of 2 (that is, without previous experience of AA). - -In CC 1 out of 2. - -In II 3 out of 3. - -In M 1 out of 2. - -In N 1 out of 3. - -In G 1 out of 3. - - -EXPERIMENTS WITH CHICKS - -The apparatus was as follows: - -[Illustration: FIG. 15. FIG. 16. FIG. 17.] - -P was simply a small pen arranged with two exits, one leading to the -inclosure where were the other chicks and food, one leading to another -pen with no exit. The drawing (Fig. 15 on this page) explains itself. A -chick was placed at A and left to find its way out. The walls were made -of books stuck up on end. - -Q was a similar pen arranged so that the real exit was harder to find. -(See Fig. 16.) - -R was still another pen similarly constructed, with four possible avenues -to be taken. (See Fig. 17.) - -S was a pen with walls 11 inches high. On the right side an inclined -plane of wire screening led from the floor of the pen to the top of its -front wall. Thence the chick could jump down to where its fellows and the -food and drink were. S was 17 × 14 in size. - -T was a pen of the same size as S, with a block of wood 3 inches by 3 -and 2 inches high in the right back corner. From this an inclined plane -led to the top of the front wall (on the right side of the box). But a -partition was placed along the left edge of this plane, so that a chick -could reach it only _via_ the wooden block, not by a direct jump. - -U was a pen 16 × 14 × 10 inches. Along the back toward the right corner -were placed a series of steps 1½ inches wide, the first 1, the second -2, and the third 3 inches high. In the corner was a platform 4 × 4, and -4 high, from which access to the top of the front wall of the pen could -be gained by scrambling up inside a stovepipe 11 inches long, inclined -upward at an angle of about 30°. From the edge of the wall the chick -could, of course, jump down to food and society. The top of the pen was -covered so that the chick could not from the platform jump onto the edge -of the stovepipe or the top of the pen wall. The only means of exit was -to go up the steps to the platform, up through the stovepipe to the front -wall, and then jump down. - -The time-curves for chicks 90, 91, 92, 93, 94 and 95, all 2-8 days old -when experimented on, follow on page 65. The scale is the same as that -in the curves of the cats and dogs. Besides these simple acts, which any -average chick will accidentally hit upon and associate, there are, in -the records of my preliminary study of animal intelligence, a multitude -of all sorts of associations which some chicks have happened to form. -Chicks have escaped from confinement by stepping on a little platform in -the back of the box, by jumping up and pulling a string like that in D, -by pecking at a door, by climbing up a spiral staircase and out through -a hole in the wall, by doing this and then in addition walking across a -ladder for a foot to another wall from which they jump down, etc. Not -every chick will happen upon the right way in these cases, but the chicks -who did happen upon it all formed the associations perfectly after enough -trials. - -The behavior of the chicks shows the same general character as that -of the cats, conditioned, of course, by the different nature of the -instinctive impulses. Take a chick put in T (inclined plane) for an -example. When taken from the food and other chicks and dropped into the -pen he shows evident signs of discomfort; he runs back and forth, peeping -loudly, trying to squeeze through any openings there may be, jumping up -to get over the wall, and pecking at the bars or screen, if such separate -him from the other chicks. Finally, in his general running around he goes -up the inclined plane a way. He may come down again, or he may go on up -far enough to see over the top of the wall. If he does, he will probably -go running up the rest of the way and jump down. With further trials he -gains more and more of an impulse to walk up an inclined plane when he -sees it, while the vain running and pecking, etc., are stamped out by the -absence of any sequent pleasure. Finally, the chick goes up the plane as -soon as put in. In scientific terms this history means that the chick, -when confronted by loneliness and confining walls, responds by those acts -which in similar conditions in nature would be likely to free him. Some -one of these acts leads him to the successful act, and the resulting -pleasure stamps it in. Absence of pleasure stamps all others out. The -case is just the same as with dogs and cats. The time-curves are shown in -Fig. 18. - -Coming now to the question of differences in intelligence between -the different animals, it is clear that such differences are hard to -estimate accurately. The chicks are surely very much slower in forming -associations and less able to tackle hard ones, but the biggest part of -the difference between what they do and what the dogs and cats do is not -referable so much to any difference in intelligence as to a difference -in their bodily organs and instinctive impulses. As between dogs and -cats, the influence of the difference in quantity of activity, in the -direction of the instinctive impulses, in the versatility of the fore -limb, is hard to separate from the influence of intelligence proper. -The best practical tests to judge such differences in general would be -differences in memory, which are very easily got at, differences in the -delicacy and complexity attainable, and, of course, differences in the -slope of the curves for the same association. If all these tests agreed, -we should have a right to rank one animal above the other in a scale -of intelligence. But this whole question of grading is, after all, not -so important for comparative psychology as its popularity could lead -one to think. Comparative psychology wants first of all to trace human -intellection back through the phylum to its origin, and in this aim is -helped little by knowing that dogs are brighter than cats, or whales than -seals, or horses than cows. Further, the whole question of ‘intelligence’ -should be resolved into particular inquiries into the development of -attention, activity, memory, etc. - -[Illustration: FIG. 18.] - -So far as concerns dogs and cats, I should decide that the former were -more generally intelligent. The main reason, however, why dogs seem to us -so intelligent is not a good reason for the belief. It is because, more -than any other domestic animal, they direct their attention to _us_, to -what we do, and so form associations connected with acts of ours. - -Having finished our attempt to give a true description of the facts of -association, so far as observed from the outside, we may now progress to -discuss its inner nature. A little preface about certain verbal usages is -necessary before doing so. Throughout I shall use the word ‘animal’ or -‘animals,’ and the reader might fancy that I took it for granted that the -associative processes were the same in all animals as in these cats and -dogs of mine. Really, I claim for my animal psychology only that it is -the psychology of just these particular animals. What this warrants about -animals in general may be left largely to the discretion of the reader. -As I shall later say, it is probable that in regard to imitation and the -power of forming associations from a lot of free ideas, the anthropoid -primates are essentially different from the cats and dogs. - -The reasons why I say ‘animals’ instead of ‘dogs and cats of certain -ages’ are two. I do think that the probability that the other mammals, -barring the primates, offer no objections to the theories here advanced -about dogs and cats is a very strong probability, strong enough to force -the burden of proof upon any one who should, for instance, say that -horse-goat psychology was not like cat-dog psychology in these general -matters. I should claim that, till the contrary was shown in any case, -my statements should stand for the mammalian mind in general, barring -the primates. My second reason is that I hate to burden the reader -with the disgusting rhetoric which would result if I had to insert -particularizations and reservations at every step. The word ‘animal’ is -too useful, rhetorically, to be sacrificed. Finally, inasmuch as most -of my theorizing will be in the line of denying certain relatively high -functions to animals, the evidence from cats and dogs is sufficient, for -they are from among the most intelligent animals, and functions of the -kind to be discussed, if absent in their case, are probably absent from -the others. - - -REASONING OR INFERENCE - -The first great question is whether or not animals are ever led to do -any of their acts by reasoning. Do they ever conclude from inference -that a certain act will produce a certain desired result, and so do it? -The best opinion has been that they do not. The best interpretation of -even the most extraordinary performances of animals has been that they -were the result of accident and association or imitation. But it has -after all been only opinion and interpretation, and the opposite theory -persistently reappears in the literature of the subject. So, although -it is in a way superfluous to give the _coup de grâce_ to the despised -theory that animals reason, I think it is worth while to settle this -question once for all. - -The great support of those who do claim for animals the ability to infer -has been their wonderful performances which resemble our own. These could -not, they claim, have happened by accident. No animal could learn to open -a latched gate by accident. The whole substance of the argument vanishes -if, as a matter of fact, animals do learn those things by accident. -_They certainly do._ In this investigation choice was made of the -intelligent performances described by Romanes in the following passages. -I shall quote at some length because these passages give an admirable -illustration of an attitude of investigation which this research will, I -hope, render impossible for any scientist in the future. Speaking of the -general intelligence of cats, Romanes says: - - “Thus, for instance, while I have only heard of one solitary - case ... of a dog which, without tuition, divined the use of - a thumb latch so as to open a closed door by jumping on the - handle and depressing the thumb-piece, I have received some - half-dozen instances of this display of intelligence on the - part of cats. These instances are all such precise repetitions - of one another that I conclude the fact to be one of tolerably - ordinary occurrence among cats, while it is certainly rare - among dogs. I may add that my own coachman once had a cat - which, certainly without tuition, learnt thus to open a door - that led into the stables from a yard into which looked some - of the windows of the house. Standing at these windows when - the cat did not see me, I have many times witnessed her _modus - operandi_. Walking up to the door with a most matter-of-course - kind of air, she used to spring at the half hoop handle just - below the thumb latch. Holding on to the bottom of this - half-hoop with one fore paw, she then raised the other to the - thumb piece, and while depressing the latter finally with her - hind legs scratched and pushed the door posts so as to open the - door.... - - “Of course in all such cases the cats must have previously - observed that the doors are opened by persons placing their - hands upon the handles and, having observed this, the animals - act by what may be strictly termed rational imitation. But it - should be observed that the process as a whole is something - more than imitative. For not only would observation alone be - scarcely enough (within any limits of thoughtful reflection - that it would be reasonable to ascribe to an animal) to enable - a cat upon the ground to distinguish that the essential part - of the process consists not in grasping the handle, but in - depressing the latch; but the cat certainly never saw any one, - after having depressed the latch, pushing the door posts with - his legs; and that this pushing action is due to an originally - deliberate intention of opening the door, and not to having - accidentally found this action to assist the process, is shown - by one of the cases communicated to me; for in this case, my - correspondent says, ‘the door was not a loose-fitting one, by - any means, and I was surprised that by the force of one hind - leg she should have been able to push it open after unlatching - it.’ Hence we can only conclude that the cats in such cases - have a very definite idea as to the mechanical properties of - a door: they know that to make it open, even when unlatched, - it requires to be _pushed_—a very different thing from trying - to imitate any particular action which they may see to be - performed for the same purpose by man. The whole psychological - process, therefore, implied by the fact of a cat opening a - door in this way is really most complex. First the animal must - have observed that the door is opened by the hand grasping - the handle and moving the latch. Next she must reason, by - ‘the logic of feelings’—‘If a hand can do it, why not a paw?’ - Then strongly moved by this idea she makes the first trial. - The steps which follow have not been observed, so we cannot - certainly say whether she learns by a succession of trials that - depression of the thumb piece constitutes the essential part - of the process, or, perhaps more probably, that her initial - observations supplied her with the idea of clicking the thumb - piece. But, however this may be, it is certain that the pushing - with the hind feet after depressing the latch must be due to - adaptive reasoning unassisted by observation; and only by the - concerted action of all her limbs in the performance of a - highly complex and most unnatural movement is her final purpose - attained.” (Animal Intelligence, pp. 420-422.) - -A page or two later we find a less ponderous account of a cat’s success -in turning aside a button and so opening a window:— - - “At Parara, the residence of Parker Bowman, Esq., a full-grown - cat was one day accidentally locked up in a room without any - other outlet than a small window, moving on hinges, and kept - shut by means of a swivel. Not long afterwards the window was - found open and the cat gone. This having happened several - times, it was at last found that the cat jumped upon the window - sill, placed her fore paws as high as she could reach against - the side, deliberately reached with one over to the swivel, - moved it from its horizontal to a vertical position, and then, - leaning with her whole weight against the window, swung it open - and escaped.” (Animal Intelligence, p. 425.) - -A description has already been given on page 31 of the small box (C), -whose door fell open when the button was turned, and also of a large -box (CC) for the dogs, with a similar door. The thumb-latch experiment -was carried on with the same box (G) for both cats and dogs, but the -door was arranged so that a greater force (1.3 kilograms) was required -in the case of the dogs. It will be remembered that the latch was so -fixed that if the thumb piece were pressed down, without contemporaneous -outward pressure of the door, the latch bar would merely drop back into -its catch as soon as the paw was taken off the door. If, however, the -door were pushed outward, the latch bar, being pressed closely against -the outer edge of its catch, would, if lifted, be likely to fall outside -it and so permit the door to open if then or later sufficient pressure -were exerted. Eight cats (Nos. 1, 2, 3, 4, 5, 6, 7 and 13) were, one -at a time, left in this thumb-latch box. All exhibited the customary -instinctive clawings and squeezings and bitings. Out of the eight all -succeeded in the course of their vigorous struggles in pressing down -the thumb piece, so that if the door had been free to swing open, they -could have escaped. Six succeeded in pushing both thumb-piece down and -door out, so that the bar did not fall back into its place. Of these five -succeeded in also later pushing the door open, so that they escaped and -got the fish outside. Of these, three, after repeated trials, associated -the complicated movements required with the sight of the interior of the -box so firmly that they attacked the thumb latch the moment they were put -in. The history of the formation of the association in the case of 3 and -of 4 is shown in the curves in Figs. 6 and 7. In the case of 13 the exact -times were not taken. The combination of accidents required was enough to -make No. 1 and No. 6 take a long time to get out. Consequently, weariness -and failure inhibited their impulses to claw, climb, etc., more than the -rare pleasure from getting out strengthened them, and they failed to -form the association. Like the cats who utterly failed to get out, they -finally ceased to try when put in. The history of their efforts is as in -Table 3: the figures in the columns represent the time (in minutes and -seconds) the animal was in the box before escaping or before being taken -out if he failed to escape. Cases of failure are designated by an F after -the figures. Double lines represent an interval of twenty-four hours. - - -TABLE 3 - - +----------+---------+ - | No. 1. | No. 6. | - +==========+=========+ - | 13.00 F | 17.50 | - | 9.30 | 3.30 | - | 1.40 | 9.00 | - | .50 | 2.10 | - | 15.00 | 1.45 | - | 6.00 F | 1.55 | - +==========+ | - | 14.00 | 13.00 | - | +=========+ - | 20.00 F | 5.00 | - | 4.30 | 2.30 | - | 20.00 F | 15.00 | - | 20.00 F | 10.00 F | - | +=========+ - | 15.00 F | 5.00 | - +==========+ | - | 60.00 F | 15.00 F | - | +=========+ - | | 10.00 F | - | +=========+ - | | 10.00 F | - +----------+---------+ - -It should be noted that, although cats 3 and 4 had had some experience -in getting out of boxes by clawing at loops and turning buttons, they -had never had anything at all like a thumb latch to claw at, nor had -they ever seen the door opened by its use, nor did they even have any -experience of the fact that the part of the box where the thumb piece -was was the door. And we may insert here, what will be stated more fully -later, that there was displayed no observation of the surroundings or -deliberation upon them. It was just a mad scramble to get out. - -Three dogs (1, 2 and 3) were given a chance to liberate themselves from -this same box. 2 and 3, who were rather inactive, failed to even push the -thumb piece down. No. 1, who was very active, did push it down at the -same time that she happened to be pushing against the door. She repeated -this and formed the association as shown in the curve on page 60. She had -had experience only of escaping by pulling a loop of string. - -Out of 6 cats who were put in the box whose door opened by a button, -not one failed, in the course of its impulsive activity, to push the -button around. Sometimes it was clawed to one side from below; sometimes -vigorous pressure on the top turned it around; sometimes it was pushed -up by the nose. No cat who was given repeated trials failed to form a -perfect association between the sight of the interior of that box and -the proper movements. Some of these cats had been in other boxes where -pulling a loop of string liberated them, 3 and 4 had had considerable -experience with the boxes and probably had acquired a general tendency to -claw at loose objects. 10, 11 and 12 had never been in _any box_ before. -The curves are on pages 41 and 43. - -Of two dogs, one, when placed in a similar but larger box, succeeded in -hitting the button in such a way as to let the door open, and formed -a permanent association, as shown by the curves on page 41. No one who -had seen the behavior of these animals when trying to escape could doubt -that their actions were directed by instinctive impulses, not by rational -observation. It is then absolutely sure that a dog or cat _can_ open a -door closed by a thumb latch or button, merely by the accidental success -of its natural impulses. If _all_ cats, when hungry and in a _small_ box, -will accidentally push the button that holds the door, an _occasional_ -cat in a _large_ room may very well do the same. If three cats out of -eight will accidentally press down a thumb piece and push open a small -door, three cats out of a thousand may very well open doors or gates in -the same way. - -But besides thus depriving of their value the facts which these -theorizers offer as evidence, we may, by a careful examination of -the method of formation of these associations as it is shown in the -time-curves, gain positive evidence that no power of inference was -present in the subjects of the experiments. Surely if 1 and 6 had -possessed any power of inference, they would not have failed to get -out after having done so several times. Yet they did. (See p. 71.) If -they had once even, much less if they had six or eight times, inferred -what was to be done, they should have made the inference the seventh or -ninth time. And if there were in these animals any power of inference, -however rudimentary, however sporadic, however dim, there should have -appeared among the multitude some cases where an animal, seeing through -the situation, knows the proper act, does it, and from then on does -it immediately upon being confronted with the situation. There ought, -that is, to be a sudden vertical descent in the time-curve. Of course, -where the act resulting from the impulse is very simple, very obvious, -and very clearly defined, a single experience may make the association -perfect, and we may have an abrupt descent in the time-curve without -needing to suppose inference. But if in a complex act, a series of -acts or an ill-defined act, one found such a sudden consummation in -the associative process, one might very well claim that reason was at -work. Now, the scores of cases recorded show no such phenomena. The -cat does not look over the situation, much less _think_ it over, and -then decide what to do. It bursts out at once into the activities which -instinct and experience have settled on as suitable reactions to the -situation ‘_confinement when hungry with food outside_.’ It does not -ever in the course of its successes realize that such an act brings -food and therefore decide to do it and thenceforth do it immediately -from _decision_ instead of from impulse. The one impulse, out of -many accidental ones, which leads to pleasure, becomes strengthened -and stamped in thereby, and more and more firmly associated with the -sense-impression of that box’s interior. Accordingly it is sooner and -sooner fulfilled. Futile impulses are gradually stamped out. The gradual -slope of the time-curve, then, shows the absence of reasoning. They -represent the wearing smooth of a path in the brain, not the decisions of -a rational consciousness. - -In a later discussion of imitation further evidence that animals do not -reason will appear. For the present, suffice it to say, that a dog, or -cat, or chick, who does not in his own impulsive activity learn to escape -from a box by pulling the proper loop, or stepping on a platform, or -pecking at a door, will not learn it from seeing his fellows do so. They -are incapable of even the inference (if the process may be dignified by -that name) that what gives another food will give it to them also. So, -also, it will be later seen that an animal cannot learn an act by being -put through it. For instance, a cat who fails to push down a thumb piece -and push out the door cannot be taught by having one take its paw and -press the thumb piece down with it. This _could_ be learned by a certain -type of associative process without inference. _Were there inference, it -surely would be learned._ - -Finally, attention may be called to the curves which show the way that -the animal mind deals with a series of acts (_e.g._ curves for G, J, K, -L and O, found on pages 45 to 55 and 60). Were there any reasoning the -animals ought early to master the method of escape in these cases (see -descriptions on pages 31 to 34) so as to do the several acts in order, -and not to repeat one after doing it once, or else ought utterly to fail -to master the thing. But, in all these experiments, where there was every -motive for the use of any reasoning faculty, if such existed, where the -animals literally lived by their intellectual powers, one finds no sign -of abstraction, or inference, or judgment. - -So far I have only given facts which are quite uninfluenced by any -possible incompetence or prejudice of the observer. These alone seem -to disprove the existence of any rational faculty in the subjects -experimented on. I may add that my observations of all the conduct of all -these animals during the months spent with them, failed to find any act -that even _seemed_ due to reasoning. I should claim that this quarrel -ought now to be dropped for good and all,—that investigation ought to -be directed along more sensible and profitable lines. I should claim -that the psychologist who studies dogs and cats in order to defend this -‘reason’ theory is on a level with a zoölogist who should study fishes -with a view to supporting the thesis that they possessed clawed digits. -The rest of this account will deal with more promising problems, of -which the first, and not the least important, concerns the facts and -theories of _imitation_. - - -IMITATION - -To the question, ‘Do animals imitate?’ science has uniformly answered, -‘Yes.’ But so long as the question is left in this general form, no -correct answer to it is possible. It will be seen, from the results -of numerous experiments soon to be described, that imitation of a -certain sort is not possible for animals, and before entering upon that -description it will be helpful to differentiate this matter of imitation -into several varieties or aspects. The presence of some sorts of -imitation does not imply that of other sorts. - -There are, to begin with, the well-known phenomena presented by the -imitative birds. The power is extended widely, ranging from the parrot -who knows a hundred or more articulate sounds to the sparrow whom a -patient shoemaker taught to get through a tune. Now, if a bird really -gets a sound in his mind from hearing it and sets out forthwith to -imitate it, as mocking birds are said at times to do, it is a mystery and -deserves closest study. If a bird, out of a lot of random noises that it -makes, chooses those for repetition which are like sounds that he has -heard, it is again a mystery _why_, though not as in the previous case a -mystery _how_, he does it. The important fact for our purpose is that, -though the imitation of sounds is so habitual, there does not appear to -be any marked general imitative tendency in these birds. There is no -proof that parrots do muscular acts from having seen other parrots do -them. But this should be studied. At any rate, until we know what sort of -sounds birds imitate, what circumstances or emotional attitudes these -are connected with, how they learn them and, above all, whether there is -in birds which repeat sounds any tendency to imitate in other lines, we -cannot, it seems to me, connect these phenomena with anything found in -the mammals or use them to advantage in a discussion of animal imitation -as the forerunner of human. In what follows they will be left out of -account, will be regarded as a specialization removed from the general -course of mental development, just as the feathers or right aortic -arch of birds are particular specializations of no consequence for the -physical development of mammals. For us, henceforth, imitation will mean -imitation minus the phenomena of imitative birds. - -There are also certain pseudo-imitative or semi-imitative phenomena which -ought to be considered by themselves. For example, the rapid loss of -the fear of railroad trains or telegraph wires among birds, the rapid -acquisition of arboreal habits among Australian rodents, the use of -proper feeding grounds, etc., may be held to be due to imitation. The -young animal stays with or follows its mother from a specific instinct to -keep near that particular object, to wit, its mother. It may thus learn -to stay near trains, or scramble up trees, or feed at certain places and -on certain plants. Actions due to following pure and simple may thus -simulate imitation. Other groups of acts which now seem truly imitative -may be indirect fruits of some one instinct. This must be kept in mind -when one estimates the supposed imitation of parents by young. Further, -it is certain that in the case of the chick, where early animal life has -been carefully observed, instinct and individual experience between them -rob imitation of practically all its supposed influence. Chicks get along -without a mother very well. Yet no mother takes more care of her children -than the hen. Care in other cases, then, need not mean instruction -through imitation. - -These considerations may prevent an unreserved acceptance of the common -view that young animals get a great number of their useful habits from -imitation, but I do not expect or desire them to lead to its summary -rejection. I should not now myself reject it, though I think it quite -possible that more investigation and experiment may finally reduce all -the phenomena of so-called imitation of parents by young to the level of -indirect results of instinctive acts. - -Another special department of imitation may be at least vaguely marked -off: namely, apparent imitation of certain limited sorts of acts which -are somewhat frequent in the animal’s life. An example will do better -than further definition. - -Some sheep were being driven on board ship one at a time. In the course -of their progress they had to jump over a hurdle. On this being removed -before all had passed it, the next sheep was seen to jump as if to get -over a hurdle, and so on for five or six, apparently sure evidence that -they imitated the action, each of the one in front. Now, it is again -possible that among gregarious animals there may be elaborate connections -in the nervous system which allow the sight of certain particular acts in -another animal to arouse the innervation leading to those acts, but that -these connections are _limited_. The reactions on this view are specific -responses to definite signals, comparable to any other instinctive or -associational reaction. The sheep jumps when he sees the other sheep -jump, not because of a general ability to do what he sees done, but -because he is furnished with the instinct to jump at such a sight, or -because his experience of following the flock over boulders and brooks -and walls has got him into the habit of jumping at the spot where he -sees one ahead of him jump; and so he jumps even though no obstacle be -in his way. If due to instinct, the only peculiarity of such a reaction -would be that the sense-impression calling forth the act would be the -same act as done by another. If due to experience, there would be an -exact correspondence to the frequent acts called forth _originally_ by -several elements in a sense-impression, one of which is essential, and -done _afterwards_ when only the _non-essentials_ are present. These two -possibilities have not been sufficiently realized, yet they may contain -the truth. On the other hand, these limited acts may be the primitive, -sporadic beginnings of the general imitative faculty which we find in -man. To this general faculty we may now turn, having cleared away some of -the more doubtful phenomena which have shared its name. - -It should be kept in mind that an imitative act may be performed quite -unthinkingly, as when a man in the mob shouts what the others shout or -claps when the others clap; may be done from an inference that since A -by doing X makes pleasure for himself, I by doing X may get pleasure -for myself; may, lastly, be done from what may be called a transferred -association. This process is the one of interest in connection with our -general topic, and most of my experiments on imitation were directed to -the investigation of it. Its nature is simple. One sees the following -sequence: ‘A turning a faucet, A getting a drink.’ If one can free this -association from its narrow confinement to A, so as to get from it the -association, ‘impulse to turn faucet, _me_ getting a drink,’ one will -surely, if thirsty, turn the faucet, though he had never done so before. -If one can from an act witnessed learn to do the act, he in some way -makes use of the sequence seen, transfers the process to himself; in the -common human sense of the word, he _imitates_. This kind of imitation -is surely common in human life. It may be apparent in ontogeny before -any power of inference is shown. After that power does appear, it still -retains a wide scope, and teaches us a majority, perhaps, of the ordinary -accomplishments of our practical life. - -Now, as the writers of books about animal intelligence have not -differentiated this meaning from the other possible ones, it is -impossible to say surely that they have uniformly credited it to animals, -and it is profitless to catalogue here their vague statements. Many -opposers of the ‘reason’ theory have presupposed such a process and used -it to replace reason as the cause of some intelligent performances. The -upholders of the reason theory have customarily recognized such a process -and claimed to have discounted it in their explanations of the various -anecdotes. So we found Mr. Romanes, in the passage quoted, discussing the -possibility that such an imitative process, without reason, could account -for the facts. In his chapter on Imitation in ‘Habit and Instinct,’ -Principal C. Lloyd Morgan, the sanest writer on comparative psychology, -seems to accept imitation of this sort as a fact, though he could, if -attacked, explain most of his illustrations by the simple forms. The fact -is, as was said before, that no one has analyzed or systematized the -phenomena, and so one cannot find clear, decisive statements to quote. - -At any rate, whether previous authorities have agreed that such a process -is present or not, it is worth while to tackle the question; and the -formation of associations by imitation, if it occurs, is an important -division of the formation of associations in general. The experiments and -their results may now be described. - - -IMITATION IN CHICKS - -No. 64 learned to get out of a certain pen (16 × 10 inches) by crawling -under the wire screening at a certain spot. There was also a chance to -get out by walking up an inclined plane and then jumping down. No. 66 was -put in with 64. After 9 minutes 20 seconds, 66 went out by the inclined -plane, although 64 had in the meantime crawled out under the screen 9 -times. (As soon as he got out and ate a little he was put back.) It was -impossible to judge how many of these times 66 really saw 64 do this. -He was looking in that direction 5 of the times. So also, in three more -trials, 66 used the inclined plane, though 64 crawled under each time. 67 -was then tried. In 4 minutes 10 seconds, he crawled under, 64 having done -so twice. Being then put in _alone_, he, without the chance to imitate, -still crawled under. So probably he went under _when with 64_ not by -imitation but by accident, just as 64 had learned the thing himself. - -[Illustration: Fig. 19. Fig. 20.] - -The accompanying figure (19) shows the apparatus used in the next -experiment. A represents the top of a box (5 × 4 inches), 13 inches above -the level of the floor C. On the floor C were the chicks and food. B is -the top of a box 10 inches high. Around the edges of A except the one -next B a wire screen was placed, and 65 was repeatedly put upon A until -he learned to go quickly back to C _via_ B. Then the screen was bent -outward at X so that a chick could barely squeeze through and down (A to -C). Eleven chicks were then one at a time placed on A with 65. In every -case but one they went A-C. In the case of the chick (75) who went A-B-C, -there could have been no imitation, for he went down _before_ 65 did. One -other went through the hole before 65 went to B. The remaining nine all -had a chance to imitate 65 and to save the uncomfortable struggle to get -through the hole, 65 going A-B-C 8 times before 68 went A-C, 2 times when -with 66 and 76, once in the case of each of the others. - -In still another experiment the apparatus was (as shown in Fig. 20) a -pen 14 inches square, 10 inches high, with a wire screen in front and a -hole 3½ inches square in the back. This hole opened into a passageway (B) -leading around to C, where were the other chicks and food. Chicks who had -failed, when put in alone, to find the way out, were put in with other -chicks who had learned the way, to see if by seeing them go out they -would learn the way. Chick 70 was given 4 trials alone, being left in the -box 76 minutes all told. He was then given 9 trials (165 minutes) with -another chick who went out _via_ B 36 times. 70 failed to follow him on -any occasion. The trials were all given in the course of two days. Chick -73 failed in 1 trial (12 minutes) to get out of himself, and was then -given 4 trials (94 minutes) with another chick who went out _via_ B 33 -times. In this experiment, as in all others reported, sure evidence that -the animals wanted to get out, was afforded by their persistent peckings -and jumpings at the screen or bars that stood between them and C. Chick -72, after 8 unsuccessful trials alone (41 minutes), was given 8 trials -with a chance to imitate. After the other chick had gone out 44 times, -72 _did go out_. He did not follow the other but went 20 seconds later. -It depends upon one’s general opinion whether one shall attribute this -one case out of three to accident or imitation. - -I also took two chicks, one of whom learned to escape from A (in Fig. 19) -by going to B and jumping down the side to the _right_ of A, the other -of whom learned to jump down the side to the _left_, and placed them -together upon A. Each took his own course uninfluenced by the other in 10 -trials. - -Chicks were also tried in several pens where there was only one possible -way of escape to see if they would learn it _more quickly_ when another -chick did the thing several times before their eyes. The method was -to give some chicks their first trial with an imitation possibility -and their second without, while others were given their first trial -without and their second with. If the ratio of the average time of the -first trial to the average time of the second is smaller in the first -class than it is in the second class, we may find evidence of this -sort of influence by imitation. Though imitation may not be able to -make an animal _do_ what he would otherwise _not do_, it may make him -do _quicker_ a thing he would have done sooner or later any way. As a -fact the ratio is _much larger_. This is due to the fact that a chick, -when in a pen with another chick, is not afflicted by the discomfort -of loneliness, and so does not try so hard to get out. So the other -chick, who is continually being put in with him to teach him the way -out, really prolongs his stay in. This factor destroys the value of -these quantitative experiments, and I do not insist upon them as -evidence against imitation, though they certainly offer none for it. I -do not give descriptions of the apparatus used in these experiments or -a detailed enumeration of the results, because in this discussion we -are not dealing primarily with imitation as a slight general factor -in forming experience, but as a definite associational process in the -mind. The utter absence of imitation in this limited sense is apparently -demonstrated by the results of the following experiments. - -V was a box 16 × 12 × 8½, with the front made of wire screening and at -the left end a little door held by a bolt but in such a way that a sharp -peck at the top of the door would force it open. - -W was a box of similar size, with a door in the same place fixed so that -it was opened by raising a bolt. To this bolt was tied a string which -went up over the top of the edge of the box and back across the box, as -in D. By jumping up and coming down with the head over this thread, the -bolt would be pulled up. The thread was 8½ inches above the floor. - -X was a box of similar size, with door, bolt and string likewise. But -here the string continued round a pulley at the back down to a platform -in the corner of the box. By stepping on the platform the door was opened. - -Y was a box 12 × 8 × 8½, with a door in the middle of the front, which I -myself opened when a chick pecked at a tack which hung against the front -of the box 1½ inches above the top of the door. - -These different acts, pecking at a door, jumping up and with the neck -pulling down a string, stepping on a platform, and pecking at a tack, -were the ones which various chicks were given a chance to imitate. The -chicks used were from 16 to 30 days old. The method of experiment was -to put a chick in, leave him 60 to 80 seconds, then put in another who -knew the act, and on his performing it, to let both escape. No cases were -counted unless the imitator apparently saw the other do the thing. After -about ten such chances to learn the act, the imitator was left in alone -for ten minutes. The following table gives the results. The imitators, -of course, had previously failed to form the association of themselves. F -denotes failure to perform the act: - - -TABLE 4 - - ======+=====+=========+============+============== - | |NO. TIMES| TIME IN | - CHICK | ACT | SAW |WHICH FAILED| FINAL TIME - ------+-----+---------+------------+-------------- - 84 | V | 38 | 45.00 F | 15.00 F - 85 | V | 30 | 30.00 F | 10.00 F - 86 | V | 44 | 55.00 F | 15.00 F - 87 | V | 26 | 35.00 F | 15.00 F - 80 | W | 54 | 60.00 F | 15.00 F - 81 | W | 40 | 45.00 F | 15.00 F - 87 | W | 27 | 30.00 F | 10.00 F - 81 | X | 18 | 20.00 F | 10.00 F - 82 | X | 21 | 20.00 F | 8.40 _Did_ - 83 | X | 33 | 35.00 F | 15.00 F - 84 | X | 46 | 55.00 F | 15.00 F - 84 | Y | 45 | 55.00 F | 15.00 F - 83 | Y | 29 | 35.00 F | 15.00 F - ======+=====+=========+============+============== - -Thus out of all these cases only one did the act in spite of the ample -chance for imitation. I have no hesitation in declaring 82’s act in -stepping on the platform the result of mere accident, and am sure that -any one who had watched the experiments would agree. - - -IMITATION IN CATS - -By reference to the previous descriptions of apparatus, it will be seen -that box D was arranged with two compartments, separated by a wire -screen. The larger of these had a front of wooden bars with a door which -fell open when a string stretched across the top was bitten or clawed -down. The smaller was closed by boards on three sides and by the wire -screen on the fourth. Through the screen a cat within could see the one -to be imitated pull the string, go out through the door thus opened and -eat the fish outside. When put in this compartment, the top being covered -by a large box, a cat soon gave up efforts to claw through the screen, -quieted down and watched more or less the proceedings going on in the -other compartment. Thus this apparatus could be used to test the power of -imitation. A cat who had no experience with the means of escape from the -large compartment was put in the closed one; another cat, who would do it -readily, was allowed to go through the performance of pulling the string, -going out, and eating the fish. Record was made of the number of times he -did so and of the number of times the imitator had his eyes clearly fixed -on him. These were called ‘times seen.’ Cases where the imitator was -looking in the general direction of the ‘imitatee’ and might very well -have seen him and probably did, were marked ‘doubtful.’ In the remaining -cases the cat did not see what was done by his instructor. After the -imitatee had done the thing a number of times, the other was put in the -big compartment alone, and the time it took him before pulling the string -was noted and his general behavior closely observed. If he failed in 5 -or 10 or 15 minutes to do so, he was released and not fed. This entire -experiment was repeated a number of times. From the times taken by the -imitator to escape and from observation of the way that he did it, we can -decide whether imitation played any part. The history of several cases -are given in the following tables. In the first column are given the -lengths of time that the imitator was shut up in the box watching the -imitatee. In the second column is the number of times that the latter did -the trick. In the third and fourth are the times that the imitator surely -and possibly saw it done, while in the last is given the time that, when -tried alone, the imitator took to pull the string, or if he failed, -the time he was in the box trying to get out. Times are in minutes and -seconds, failures denoted by F: - - -TABLE 5 (a) - - =======================+=====================================+=========== - | NO. 7 IMITATING NO. 2 | - --------------+--------+------------+-----------+------------+----------- - | Time |No. of times| No. of |No. of times| Time of 7 - |Watching| 2 did |times 7 saw| Doubtful |when alone - --------------+--------+------------+-----------+------------+----------- - | 10.00 | 11 | 3 | 5 | - After 48 Hours| 11.00 | 10 | 4 | 2 | - | 12.00 | 20 | 4 | 13 | 10.00 F - | | | | | 1.00[8] - After 24 Hours| 8.00 | 20 | 6 | 11 | 3.30 - | | | | | 10.00 F - | 13.00 | 25 | 8 | 12 | 20.00 F - After 24 Hours| 9.00 | 20 | 4 | 11 | 10.00 F - After 24 Hours| 12.00 | 35 | 5 | 21 | 30.00 F - After 2 Hours | 10.00 | 25 | 3 | 8 | 25.00 F - After 24 Hours| 15.00 | 35 | 6 | 21 | 20.00 F - After 24 Hours| 6.00 | 20 | 0 | 7 | 10.00 F - Total times surely and possibly seen,— 43 111 | - =============================================================+=========== - - -TABLE 5 (b) - - =======================+=====================================+=========== - | NO. 5 IMITATING NO. 2 | - --------------+--------+------------+-----------+------------+----------- - | Time |No. of times| No. of |No. of times| Time of 5 - |Watching| 2 did |times 5 saw| Doubtful |when alone - --------------+--------+------------+-----------+------------+----------- - | 12.00 | 15 | 3 | 8 | 5.00 F - After 2 Hours| 10.00 | 8 | 4 | 4 | - After 24 Hours| 5.00 | 5 | 0 | 3 | - After 1 Hour | 14.00 | 10 | 5 | 3 | 10.00 F - After 1 Hour | 13.00 | 22 | 7 | 11 | 10.00 F - After 24 Hours| 7.00 | 15 | 3 | 8 | 5.00 F - After 48 Hours| 18.00 | 20 | 2 | 9 | 20.00 F - After 24 Hours| 14.00 | 20 | 2 | 10 | 30.00 F - After 24 Hours| 10.00 | 20 | 7 | 12 | 20.00 F - Total times surely and possibly seen,— 33 68 | - =============================================================+=========== - - -TABLE 5 (c) - - =======================+=====================================+=========== - | NO. 6 IMITATING NO. 2 | - --------------+--------+------------+-----------+------------+----------- - | Time |No. of times| No. of |No. of times| Time of 6 - |Watching| 2 did |times 6 saw| Doubtful |when alone - --------------+--------+------------+-----------+------------+----------- - | 12.00 | 30 | 0 | 19 | 1.10[9] - After 48 Hours| 11.00 | 30 | 0 | 11 | 9.30 - After 72 Hours| 10.00 | 30 | 0 | 15 | 3.00 - After 72 Hours| 6.00 | 20 | 3 | 7 | 1.50 - After 24 Hours| 9.00 | 30 | 1 | 13 | 10.00 F - After 24 Hours| 10.00 | 30 | 6 | 9 | 10.00 F - After 24 Hours| 10.00 | 30 | 1 | 8 | 9.40 - Total times surely and possibly seen,— 11 82 | - =============================================================+=========== - - -TABLE 5 (d) - - =======================+=====================================+=========== - | NO. 3 IMITATING NO. 2 | - --------------+--------+------------+-----------+------------+----------- - | 8.00 | 30 | 2 | 19 | 3.30[10] - | | | | | 3.30 - After 48 Hours| 10.00 | 30 | 2 | 14 | .20 - | | | | | .20 - After 72 Hours| 10.00 | 30 | 2 | 8 | .18 - | | | | | .08 - Total times surely and possibly seen,— 6 41 | - =============================================================+=========== - -Before entering upon a discussion of the facts shown by these tables, -we must describe the behavior of the imitators, when, after seeing 2 -pull the string, they were put in alone. In the opinion of the present -observer there was not the slightest difference between their behavior -and that of cats 4, 10, 11, 12 and 13, who were put into the same -position without ever having seen 2 escape from it. 6, 7, 5 and 3 paid -no more attention to the string than they did, but struggled in just -the same way. No one, I am sure, who had seen them, would have claimed -that their conduct was at all influenced by what they had seen. When -they did hit the string the act looked just like the accidental success -of the ordinary association experiment. But, besides these personal -observations, we have in the impersonal time-records sufficient proofs -of the absence of imitation. If the animals pulled the string from -having seen 2 do so, they ought to pull it in each individual case at -an approximately regular length of time after they were put in, and -presumably pretty soon thereafter. That is, if an association between -the sight of that string in that total situation and a certain impulse -and consequent freedom and food had been formed in their minds by the -observation of the acts of 2, they ought to pull it _on seeing it_, and -if any disturbing factor required that a certain time should elapse -before the imitative faculty got in working order, that time ought to be -somewhere near constant. The times were, as a fact, long and irregular -in the extreme. Furthermore, if the successful cases were even in part -due to imitation, the times ought to decrease the more they saw 2 do the -thing. Except with 3, they _increase_ or give place to failures. Whereas -6 and 7, if they had been put in again immediately after their first -successful trial and from then on repeatedly, would have unquestionably -formed the association, they did not, when put in after a further -chance to increase their knowledge by imitation, do the thing as soon -as before. The case of 3 is not here comparable to the rest because he -_was_ given three trials in immediate succession. He was a more active -cat and quicker to learn, as may be seen by comparing his time curves -with those of 7, 6 and 5. That the mere speed with which he mastered -this association is no sign that imitation was present may be seen by -reference to the time curves of 4 and 13 (on p. 43). - -Some cats were also experimented with in the following manner. They were -put into a box [No. 7 into box A (O at front), No. 5 into B (O at back)] -and left for from 45 to 75 seconds. Then a cat who knew the way to get -out was put in, and, of course, pulled at the loop and opened the door. -_Both cats then went out and both were fed._ After the cat had been -given a number of such chances to learn by imitation, he was put in and -left until he did the thing, or until 5 or 10 minutes elapsed. As in the -preceding experiments, no change in their behavior which might signify -imitation was observed. No. 7 acted exactly like 3, or 10, or 11, when -put in the box, apparently forming the association by accident in just -the same way. Good evidence that he did not imitate is the fact that, -whereas 1 (whom he saw) pulled the loop with his teeth, 7 pulled it with -his paw. 5 failed to form the association, though he saw 3 do it 8 times -and probably saw him 18 times more. He did get out twice by clawing the -_string_ in the _front_ of the box, not the _loop_ in the _back_, as 3 -did. These successes took place early in the experiment. After that he -failed when left alone to get out at all. - -Another experiment was made by a still different method. My cats were -kept in a large box about 4 ft. high, the front of which was covered with -poultry-yard netting. Its top was a board which could be removed. To save -opening the door and letting them all loose, I was in the habit of taking -them out by the top when I wanted to experiment with them. Of course the -one who happened to climb up (perhaps attracted by the smell of fish -on my fingers) was most likely to be taken out and experimented with -and fed. Thus they formed the habit of climbing up the front of the box -whenever I approached. Of three cats which I obtained at the same time, -one did not after 8 or 10 days acquire this habit. Even though I held out -a piece of fish through the netting, he would not climb after it. It was -reasonable to suppose that imitation might overcome this sluggishness, -if there were any imitation. I therefore put two cats with him and had -them climb up 80 times before his eyes and get fish. He never followed or -tried to follow them. - -4 and 3 had been subjected to the following experiment. I would make a -certain sound and after 10 seconds would go up to the cage and hold the -fish out to them through the netting at the top. They would then, of -course, climb up and eat it. After a while, they began to climb up upon -hearing the signal (4) or before the 10 seconds were up. I then took 12 -and 10, who were accustomed to going up when they saw me approach, but -who had no knowledge of the fact that the signal meant anything, and gave -them each a chance to imitate 3. That is, one of them would be left in -the box with 3, the signal would be given, and after from 5 to 10 seconds -3 would climb up. At 10 seconds I would come up with food, and then, -of course, 12 would climb up. This was repeated again and again. The -question was whether imitation would lead them to form the association -more quickly than they would have done alone. It did not. That when at -last they did climb up before 10 seconds was past, that is, before I -approached with food, it was not due to imitation, is shown by the fact -that on about half of such occasions they climbed up _before 3 did_. That -is, they reacted to the _signal_ by _association_, not to his _movements_ -by _imitation_. - - -IMITATION IN DOGS - -Here the method was not to see if imitation could arouse more quickly an -act which accident was fairly likely to bring forth sooner or later, but -to see if, where accident failed, imitation would succeed. - -3 was found to be unable of himself to escape from box BB1, and was then -given a chance to learn from watching 1. The back of box BB1 was torn -off and wire netting substituted for it. Another box with open front was -placed directly behind and against box BB1. No. 3, who was put in this -second box, could thus see whatever took place in and in front of box BB1 -(O at back, high). The record follows:— - - -TABLE 6 (a) - - =======================================+================================ - | DOG 3 IMITATING DOG 1 - --------------------------------+------+------+--------------+---------- - | Times| Times|Times probably| Time - | 1 did| 3 saw| 3 saw | in alone - --------------------------------+------+------+--------------+---------- - | 30 | 7 | 14 | 3.00 F - After 1 Hour | 35 | 9 | 14 | 3.00 F - After 1 Hour | 10 | 3 | 3 | 5.00 F - After 24 Hours | 20 | 6 | 8 | - | 30 | 8 | 13 | 6.00 F - After 48 Hours | 25 | 8 | 11 | 8.00 F - | 25 | 6 | 12 | 6.00 F - | 25 | 9 | 7 | 10.00 F - After 24 Hours | 30 | 10 | 11 | 40.00 F - | | | | - Total times surely and possibly seen,— 66 93 | - =============================================================+========== - -A similar failure to imitate was observed in the case of another simple -act. No. 1, as may be seen on page 60, had learned to escape from a pen -about 8 by 5 feet by jumping up and biting a cord which ran from one end -of the pen to the other and at the front end was tied to the bolt which -held the door. Dogs 2 and 3 had failed in their accidental jumping and -pawing to hit this cord, and were then given a chance to learn by seeing -1 do so, escape, and, of course, be fed. 1 always jumped in the same way, -biting the cord at the same place, namely, where a loose end from a knot -in it hung down 4 or 5 inches. 2 and 3 would either be tied up in the pen -or left in a pen at one side. They had a perfect chance to see 1 perform -his successful act. After every twenty or thirty performances by 1, 2 and -3 would be put in alone. It should be remembered that here, as also in -the previous experiment and all others, the imitators certainly _wanted_ -to get out when thus left in alone. They struggled and jumped and pawed -and bit, but they never jumped _at the cord_. Their records follow:— - - -TABLE 6 (b) - - =======================================+============================== - | DOG 2 IMITATING DOG 1 - --------------------------------+------+------+---------+------------- - | Times| Times| Times | Time 2 was - | 1 did| 2 saw| Doubtful| in alone - --------------------------------+------+------+---------+------------- - | 30 | 9 | 11 | 10.00 F - After 1 Hour | 30 | 10 | 9 | 10.00 F - After 48 Hours | 25 | 8 | 8 | - After 1 Hour | 10 | 3 | 4 | 9.00 F[11] - After 24 Hours | 30 | 8 | 12 | 15.00 F - After 1 Hour | 30 | 9 | 12 | 15.00 F - After 48 Hours | 20 | 7 | 6 | 10.00 F - | 20 | 8 | 7 | - After 48 Hours | 30 | 6 | 8 | 15.00 F - After 24 Hours | 15 | 2 | 4 | 10.00 F - Total times surely and possibly seen,— 70 81 | - ========================================================+============= - - -TABLE 6 (c) - - =======================================+============================== - | DOG 3 IMITATING DOG 1 - --------------------------------+------+------+---------+------------- - | Times| Times| Times | Time 3 was - | 1 did| 3 saw| Doubtful| in alone - --------------------------------+------+------+---------+------------- - | 30 | 10 | 10 | 10.00 F - After 1 Hour | 30 | 9 | 10 | 10.00 F - After 1 Hour | 15 | 6 | 4 | - After 24 Hours | 30 | 9 | 11 | 15.00 F - After 24 Hours | 30 | 10 | 12 | 15.00 F - After 1 Hour | 30 | 8 | 9 | 10.00 F - After 48 Hours | 20 | 6 | 7 | 40.00 F - After 1 Hour | 20 | 6 | 5 | - After 48 Hours | 30 | 8 | 9 | 15.00 F - After 24 Hours | 15 | 3 | 4 | 20.00 F - Total times surely and possibly seen,— 75 81 | - ========================================================+============= - -Another corroborative, though not very valuable, experiment was the -following: Dog 3 had been taught for the purpose of another experiment -to jump up on a box and beg when I held a piece of meat above the box. I -then caused him to do this 110 times (within two days) in the presence of -1. Although 1 saw him at least 20 per cent of the times (3 was always fed -each time he jumped on the box), he never tried to imitate him. - -It seems sure from these experiments that the animals were unable -to form an association leading to an act from having seen the other -animal, or animals, perform the act in a certain situation. Thus we -have further restricted the association process. Not only do animals -not have associations accompanied, more or less permeated and altered, -by inference and judgment; they do not have associations of the sort -which may be acquired from other animals by imitation. What this implies -concerning the actual mental content accompanying their acts will be -seen later on. It also seems sure that we should give up imitation as an -_a priori_ explanation of any novel intelligent performance. To say that -a dog who opens a gate, for instance, need not have reasoned it out _if -he had seen another dog do the same thing_, is to offer, instead of one -false explanation, another equally false. Imitation in any form is too -doubtful a factor to be presupposed without evidence. And if a general -imitative faculty is not sufficiently developed to succeed with such -simple acts as those of the experiments quoted, it must be confessed that -the faculty is in these higher mammals still rudimentary and capable -of influencing to only the most simple and habitual acts, or else that -for some reason its sphere of influence is limited to a certain class -of acts, possessed of some _qualitative difference_ other than mere -simplicity, which renders them imitable. The latter view seems a hard -one to reconcile with a sound psychology of imitation or association at -present, without resorting to instinct. Unless a certain class of acts -are by the innate mental make-up especially tender to the influence of -imitation, the theory fails to find good psychological ground to stand -on. The former view may very well be true. But in any case the burden -of proof would now seem to rest upon the adherents to imitation; the -promising attitude would seem to be one which went without imitation -as long as it could, and that is, of course, until it surely found it -present. - -Returning to imitation considered in its human aspect, to imitation -as a transferred association in particular, we find that here our -analytical study of the animal mind promises important contributions to -general comparative psychology. If it is true, and there has been no -disagreement about it, that the primates do imitate acts of such novelty -and complexity that only this out-and-out kind of imitation can explain -the fact, we have located one great advance in mental development. Till -the primates we get practically nothing but instincts and individual -acquirement through impulsive trial and error. Among the primates we -get also acquisition by imitation, one form of the increase of mental -equipment by tradition. The child may learn from the parent quickly -without the tiresome process of seeing for himself. The less active and -less curious may share the progress of their superiors. The brain whose -impulses hitherto could only be dislodged by specific sense-impressions -may now have any impulse set agoing by the sight of the movement to which -it corresponds. - -All this on the common supposition that the primates _do_ imitate, that -a monkey in the place of these cats and dogs _would_ have pulled the -string. My apology for leaving the matter in this way without experiments -of my own is that the monkey which I procured for just this purpose -failed in two months to become tame enough to be thus experimented on. -Accurate information about the nature and extent of imitation among -the primates should be the first aim of further work in comparative -psychology, and will be sought by the present writer as soon as he can -get subjects fit for experiments. - - In a questionnaire which was sent to fifteen animal trainers, - the following questions were asked:— - - 1. “If one dog was in the habit of ‘begging’ to get food and - another dog saw him do it ten or twenty times, would the second - dog then beg himself?” - - 2. “In general is it easier for you to teach a cat or dog a - trick if he has seen another do it?” - - 3. “In general do cats imitate each other? Do dogs? Do - monkeys?” - - 4. “Give reasons for your opinion, and please write all the - reasons you have.” - -Five gentlemen (Messrs. R. C. Carlisle, C. L. Edwards, V. P. Wormwood, H. -S. Maguire and W. E. Burke) courteously responded to my questionnaire. -All are trainers of acknowledged reputation. To these questions on -imitation four replied. - -To the first question we find the following answers: (_a_) “Most dogs -would.” (_b_) “Yes; he will very likely do it. He will try and imitate -the other dog _generally_.” (_c_) “If a young dog with the mother, it -would be very apt to.... With older dogs, it would depend very much upon -circumstances.” (_d_) “He would not.” - -To 2 the answers were: (_a_) “Very much easier.” (_b_) “It is always -easier if they see another one do it often.” (_c_) “This would also -depend on certain conditions. In teaching to jump out of a box and -in again, seeing another might help, but in teaching something very -difficult, I do not think it would be the case.” (_d_) “It is not.” - -To 3 the answers were: (_a_) “Yes. Some. More than either dogs or cats.” -(_b_) “Yes. Yes. Yes.” (_c_) “In certain things, yes; mostly in those -things which are in compliance to the laws of their own nature.” (_d_) -“No. No. Yes, they are born imitators.” - -The only definite answer to question 4 was: “Take a dog or cat and close -them up in a room and go in and out several times, and you will find that -they will go to the door and stand up on their hind legs with front paws -on the door knob and try to open the door to get out. I could also give -you a hundred more such reasons.” This was given by (_b_). - -The replies to a test question, however, go to show that these opinions -regarding imitation may be mistaken. Question 8 was: “If you wanted to -teach a cat to get out of a cage by opening an ordinary thumb latch and -then pushing the door, would you take the cat’s paw and push down the -thumb piece with it and then push the door open with the paw, or would -you just leave the cat inside until it learned the trick itself?” The -second is certainly the better way, as will be seen in a later part of -this paper, and pushing the latch with the cat’s paw has absolutely no -beneficial influence on the formation of the association, yet (_a_) and -(_b_) both chose the first way, and (_c_) answered ambiguously. Further, -the only reason given is, of course, no reason at all. It proves too -much, for if there were such imitation as that, my cats and dogs would -surely have done the far simpler things required of them. I cannot find -that trainers make any practical use of imitation in teaching animals -tricks, and on the whole I think these replies leave the matter just -where it was before. They are mere opinions—not records of observed -facts. It seems arrogant and may seem to some unjustifiable thus to -discard testimony, to stick to a theory based on one’s own experiments in -the face of these opinions. If I had wished to gain applause and avoid -adverse criticism, I would have abstained from upholding the radical -view of the preceding pages. At times it seems incredible to me that the -results of my experiments should embody the truth of the matter, that -there should be no imitation. The theory based on them seems, even to me, -too radical, too novel. It seems highly improbable that I should be right -and all the others wrong. But I cannot avoid the responsibility of giving -what seems to my judgment the most probable explanation of the results of -the experiments; and that is the radical explanation already given. - - -THE MENTAL FACT IN ASSOCIATION - -It is now time to put the question as to just what is in an animal’s -mind when, having profited by numerous experiences, he has formed the -association and does the proper act when put in a certain box. The -commonly accepted view of the mental fact then present is that the sight -of the inside of the box reminds the animal of his _previous pleasant -experience after escape_ and _of the movements_ which he made which were -immediately followed by and so associated with that escape. It has been -taken for granted that _if the animal remembered the pleasant experience -and remembered the movement, he would make the movement_. It has been -assumed that the association was _an association of ideas_; that when -one of the ideas was of a movement the animal was capable of making -the movement. So, for example, Morgan says, in the ‘Introduction to -Comparative Psychology’: “If a chick takes a ladybird in its beak forty -times and each time finds it nasty, this is of no practical value to the -bird unless the sight of the insect suggests _the nasty taste_” (p. 90). - -Again, on page 92, Morgan says, “_A race after the ball_ had been -suggested through the channel of olfactory sensations.” Also, on page -86 “... the visual impression suggested the idea or representation of -unpleasant gustatory experience.” The attitude is brought out more -completely in a longer passage on page 118: “On one of our first ascents -one of them put up a young coney, and they both gave chase. Subsequently -they always hurried on to this spot, and, though they never saw another -coney there, reiterated disappointment did not efface _the memory of -that first chase_, or so it seemed.” That is, according to Morgan, the -dogs thought of the chase and its pleasure, on nearing the spot where it -had occurred, and so hurried on. On page 148 of ‘Habit and Instinct,’ we -read, “Ducklings so thoroughly associated water with the sight of their -tin that they tried to drink from it and wash in it when it was empty, -nor did they desist for some minutes,” and this with other similar -phenomena is attributed to the ‘association by contiguity’ of human -psychology. - -From these quotations it seems fairly sure that if we should ask Mr. -Morgan, who is our best comparative psychologist, what took place in the -mind of one of these cats of our experiments during the performance of -one of the ‘tricks’ he would reply: “The cat performs the act because -of the association of ideas. He is reminded by the sight of the box and -loop of his experience of pulling that loop and of eating fish outside. -So he goes and pulls it again.” This view has stood unchallenged, but its -implication is false. It implies that an animal, whenever it thinks of -an act, can supply an _impulse to do_ the act. It takes for granted that -the performance of a cat who gets out of a box is mentally like that of -a man who thinks of going down street or of writing a letter and then -does it. The mental process is not alike in the two cases, for animals -can _not_ provide the impulse to _do_ whatever act they think of. _No cat -can form an association leading to an act unless there is included in -the association an impulse of its own which leads to the act._ There is -no general storehouse from which the impulse may be supplied after the -association is formed. - -Before describing the experiments which justify these statements, it will -be worth while to recall the somewhat obvious facts about the composition -of one of these associations. There might be in an association, such as -is formed after experience with one of our boxes, the following elements:— - -1. Sense-impression of the interior of the box, etc. - -2. (_a_) Discomfort and (_b_) desire to get out. - -3. Representation of oneself pulling the loop. - -4. Fiat comparable to the human “I’ll do it.” - -5. The impulse which actually does it. - -6. Sense-impression of oneself pulling the loop, seeing one’s paw in a -certain place, feeling one’s body in a certain way, etc. - -7. Sense-impression of going outside. - -8. Sense-impression of eating, and the included pleasure. - -Also between 1 and 4 we may have 9, representations of one’s experience -in going out, 10, of the taste of the food, etc. 6, 7 and 8 come after -the act and do not influence it, of course, except in so far as they -are the basis of the future 3’s, 9’s and 10’s. About 2 we are not at -present disputing. Our question is as to whether 3 or 5 is the essential -thing. In human associations 3 certainly often is, and the animals -have been credited with the same kind. Whatever he _thinks_, Professor -Morgan surely _talks_ as if 1 aroused 9 and 10 and 3 and leaves 5 to be -supplied at will. We have affirmed that 5 is the essential thing, that no -association without a specific 5 belonging to it and acquired by it can -lead to an act. Let us look at the reasons. - -A cat has been made to go into a box through the door, which is then -closed. She pulls a loop and comes out and gets fish. She is made to go -in by the door again, and again lets herself out. After this has happened -enough times, the cat will of her own accord go into the box after eating -the fish. It will be hard to keep her out. The old explanation of this -would be that the cat associated the memory of being in the box with the -subsequent pleasure, and therefore performed the equivalent of saying -to herself, “Go to! I will go in.” The thought of _being in_, they say, -makes her _go in_. _The thought of being in will not make her go in._ -For if, instead of pushing the cat toward the doorway or holding it -there, and thus allowing it to itself give the impulse, to innervate the -muscles, to walk in, you shut the door first and drop the cat in through -a hole in the top of the box, she will, after escaping as many times -as in the previous case, _not_ go into the box of her own accord. She -has had exactly the same opportunity of connecting the idea of being in -the box with the subsequent pleasure. Either a cat cannot connect ideas, -representations, at all, or she has not the power of progressing from the -thought of being in to the act of going in. The only difference between -the first cat and the second cat is that the first cat, in the course of -the experience, has the impulse to crawl through that door, while the -second has not the impulse to crawl through the door or to drop through -that hole. So, though you put the second cat on the box beside the hole, -she doesn’t try to get into the box through it. The impulse is the _sine -qua non_ of the association. The second cat has everything else, but -cannot supply that. These phenomena were observed in six cats, three of -which were tried by the first method, three by the second. Of the first -three, one went in himself on the 26th time and frequently thereafter, -one on the 18th and the other on the 37th; the two last as well as the -first did that frequently in later trials. The other three all failed to -go in themselves after 50, 60 and 75 trials, respectively. - -The case of No. 7 was especially instructive, though not among these six. -No. 7 had had some trials in which it was put in through the door, but -ordinarily in this particular experiment was dropped in. After about 80 -trials it would frequently exhibit the following phenomena: It would, -after eating the fish, go up to the doorway and, rushing from it, search -for fish. The kitten was very small and would go up into the doorway, -whirl round and dash out, all in one quick movement. The best description -of its behavior is the paradoxical one that it went out without going -in. The association evidently concerned what it had _done_, what it had -an impulse for, namely, _coming out through that door_ to get fish, not -what it remembered, had a representation of. - -Still more noteworthy evidence is found in the behavior of cats and -dogs who were put in these boxes, left one or two minutes, and then -put through the proper movement. For example, a cat would be put in B -(O at back) and left two minutes. I would then put my hand in through -the top of the box, take the cat’s paw and with it pull down the loop. -The cat would then go out and eat the fish. This would be done over and -over again, and after every ten or fifteen such trials the cat would be -left in alone. If in ten or twenty minutes he did not escape, he would -be taken out through the top and not fed. In one series of experiments -animals were taken and thus treated in boxes from which their own -impulsive activity had failed to liberate them. The results, given in -the table below, show that no animal who fails to perform an act in the -course of his own impulsive activity will learn it by being put through -it. - -In these experiments some of the cats and all of the dogs but No. 1 -showed no agitation or displeasure at my handling from the very start. -Nor was there any in Dog 1 or the other cats after a few trials. It may -also be remarked that in the trials alone which took place during and -at the end of the experiment the animals without exception showed that -they did not fail to perform the act from lack of a desire to get out. -They all tried hard enough to get out and would surely have used the -association if they had formed it. - - -TABLE 7 - - ===========+===============================+==============+============+ - Individual | Apparatus |Time in which |Number of | - | |impulsive |times the | - | |activity |animal was | - | |failed to lead|put through | - | |to the act |the movement| - -----------+-------------------------------+--------------+------------+ - Cat 1 | F (String outside unfastened) | 55.00 | 77 | - Cat 5 | G (Thumb latch) | 57.00 | 59 | - Cat 7 | G (Thumb latch) | 50.00 | 30 | - Cat 2 | G (Thumb latch) | 54.00 | 141 | - Dog 2 | BB1 (O at back, high) | 48.00 | 30 | - Dog 3 | BB1 (O at back, high) | 20.00 | 85 | - Dog 2 | M (Lever outside) | 15.00 | 95 | - Dog 1 | FF[12] | 30.00 | 110 | - Chick 89 | X (see page 53) | 20.00 | 30 | - Cat 13 | KKK,[13][14] | 40.00 | 65 | - ===========+===============================+==============+============+ - - ===========+===============================+===============+======== - Individual | Apparatus |Time in which |Time of - | |this experience|final - | |failed to lead |trial - | |to the act | - -----------+-------------------------------+---------------+-------- - Cat 1 | F (String outside unfastened) | 120.00 | 20.00 - Cat 5 | G (Thumb latch) | 55.00 | 10.00 - Cat 7 | G (Thumb latch) | 35.00 | 10.00 - Cat 2 | G (Thumb latch) | 110.00 | 20.00 - Dog 2 | BB1 (O at back, high) | 80.00 | 60.00 - Dog 3 | BB1 (O at back, high) | 55.00 | 10.00 - Dog 2 | M (Lever outside) | 140.00 | 30.00 - Dog 1 | FF[12] | 135.00 | 60.00 - Chick 89 | X (see page 53) | 60.00 | 30.00 - Cat 13 | KKK,[13][14] | 60.00 | 10.00 - ============+===============================+===============+======== - -Now, the only difference between the experiences of the animals in these -experiments and their experiences in those where they let themselves -out, is that here they only saw and felt themselves making the movement, -whereas in the other case they also felt the impulse, gave the -innervation. That, then, is the essential. It may be objected that the -animals failed because they did not _attend_ to the process of being put -through the movement, that, had they attended to it, they would later -themselves have made the movement. It is, however, improbable that out -of fifty times an animal should not have attended to what was going on -at least two or three times. But if seeing himself do it was on a par -with feeling an impulse to and so doing it, even two or three times -would suffice to start the habit. And it is even more improbable that an -experience should be followed by keen pleasure fifty times and not be -attended to with might and main, unless animals attend _only_ to their -own impulses and the excitements thereof. But if the latter be true, it -simply affirms our view from a more fundamental standpoint. - -In another set of experiments animals were put in boxes with whose -mechanisms they had had no experience, and from which they might or -might not be able to escape by their own impulsive acts. The object was -to see whether the time taken to form the association could be altered -by my instruction. The results turned out to give a better proof of the -inability to form an association by being put through the act than any -failure to change the time-curve. For it happened in all but one of -the cases that the movement which the animal made to open the door was -different from the movement which I had put him through. Thus, several -cats were put through (in Box C [button]) the following movement: I took -the right paw and, putting it against the lower right-hand side of the -button, pushed it round to a horizontal position. The cats’ ways were -as follows: No. 1 turned it by clawing vigorously at its top; No. 6, by -pushing it round with his nose; No. 7, in the course of an indiscriminate -scramble at first, in later trials either by pushing with his nose or -clawing at the top, settling down finally to the last method. Nos. 2 and -5 did it as No. 1 did. Cat 2 was tried in B (O at back). I took his paw -and pressed the loop with it, but he formed the habit of clawing and -biting the string at the top of the box near the front. No. 1 was tried -in A. I pressed the loop with his paw, but he formed the habit of biting -at it. - -In every case I kept on putting the animal through the act every time, -if at the end of two minutes (one in several cases) it had not done it, -even after it had shown, by using a different way, that my instruction -had no influence. I never succeeded in getting the animal to change its -way for mine. Moreover, if any one should fancy that the animal really -profited by my instruction so as to learn what result to attain, namely, -the turning of a certain button, but chose a way of his own to turn -it, he would be deluding himself. The time taken to learn the act with -instruction was no shorter than without. - -If, then, an animal happens to learn an act by being put through it, it -is just happening, nothing more. Of course, you may _direct_ the animal’s -efforts so that he will perform the act himself the sooner. For instance, -you may hold him so that his accidental pawing will be sure to hit the -vital point of the contrivance. But the animal cannot form an association -leading to an act unless the particular impulse to that act is present as -an element of the association; he cannot supply it from a general stock. -The groundwork of animal associations is not the association of _ideas_, -but the association of idea or sense-impression with _impulse_. - -In the questionnaire mentioned elsewhere, some questions were asked with -a view to obtaining corroboration or refutation of this theory that an -impulse or innervation is a necessary element in every association formed -if that association leads to an act. The questions and answers were:— - -_Question 1_: “If you wanted to teach a horse to tap seven times with his -hoof when you asked him, ‘How many days are there in a week?,’ would you -teach him by taking his leg and making him go through the motions?” - -_A_ answered, “Yes! at first.” - -_B_ answered, “No! I would not.” - -_C_ answered, “At first, yes!” - -_D_ answered, “No!” - -_Question 2_: “Do you think you _could_ teach him that way, even if -naturally you would take some other way?” - -_A_ answered, “In time, yes!” - -_B_ answered, “I think it would be a very hard way.” - -_C_ answered, “Certainly I do.” - -_D_ answered, “I do not think I could.” - -_E_ answered, “Yes.” - -_Question 3_: “How would you teach him?” - -_A_ answered, “I should tap his foot with a whip, so that he would raise -it, and reward him each time.” - -_B_ answered, “I should teach him by the motion of the whip.” - -_C_ answered, “First teach him by pricking his leg the number of times -you wanted his foot lifted.” - -_D_ answered, “You put figure 2 on blackboard and touch him on leg twice -with cane, and so on.” - -_E_ answered ambiguously. - -It is noteworthy that even those who think they _could_ teach an animal -by putting him through the trick do not use that method, except at first. -And what they really do then is probably to stimulate the animal to the -reflex act of raising his hoof. The hand simply replaces the cane or -whip as the means of stimulus. The answers are especially instructive, -because the numerous counting tricks done by trained horses seem, at -first, to be incomprehensible, unless the trainer can teach the horse by -putting it through the movement the proper number of times. The counting -tricks performed by Mascot, Professor Maguire’s horse, were quoted to me -by a friend as incomprehensible on my theory. The answers given above -show how simple the thing really is. All the counting-tricks of all the -intelligent horses depend on the fact that a horse raises his hoof when -a certain stimulus is given. One simple reaction gives the basis for a -multitude of tricks. In the same way other tricks, which at first sight -seem to require that the animal should learn by being put through the -movement, may depend on some simple reflex or natural impulse. - -Another question was, “How would you teach a cat to get out of a box, the -door of which was closed with a thumb latch?” - -_A_ answered, “I should use a puffball as a plaything for the cat to claw -at.” This means, I suppose, that he would get the cat to claw at the -puffball and thus direct its clawings to the vicinity of the thumb piece. - -_B_ answered, “I would put the cat in and get it good and hungry and then -open the door by lifting the latch with my finger. Then put some food -that the cat likes outside, and she will soon try to imitate you and so -learn the trick.” - -_C_ answered, “I would first adjust all things in connection with the -surroundings of the cat so they would be applicable to the laws of its -nature, and then proceed to teach the trick.” - -I suppose this last means that he would fix the box so that some of the -cat’s instinctive acts would lead it to perform the trick. The answer -given by _B_ means apparently that he would simply leave the thing to -accident, for any such imitation as he supposes is out of the question. -At all events, none of these would naturally start to teach the trick by -putting the animal through the motions, which, were it a possible way, -would probably be a traditional one among trainers. On the whole, I see -in these data no reason for modifying our dogma that animals cannot learn -acts without the impulse. - -Presumably the reader has already seen budding out of this dogma a new -possibility, a further simplification of our theories about animal -consciousness. The possibility is that animals may have _no images or -memories at all, no ideas to associate_. Perhaps the entire fact of -association in animals is the presence of sense-impressions with which -are associated, by resultant pleasure, certain impulses, and that, -therefore, and therefore only, a certain situation brings forth a certain -act. Returning to our analysis of the association, this theory would say -that there was no (9) or (10) or (3) or (4), that the sense-impression -gave rise, when accompanied by the feeling of discomfort, to the impulse -(5) directly, without the intervention of any representations of the -taste of the food, or the experience of being outside, or the sight of -oneself doing the act. This theory might be modified so as to allow -that the representations could be there, but to deny that they were -necessary, were inevitably present, that the impulse was connected to the -sense-impression through them. It would then claim that the effective -part of the association was a direct bond between the situation and the -impulse, but would not cut off the possibility of there being an aura -of memories along with the process. It then becomes a minor question of -interpretation which will doubtless sooner or later demand an answer. I -shall not try to answer it now. The more radical question, the question -of the utter exclusion of representative trains of thought, of any -genuine association of _ideas_ from the mental life of animals, is -worth serious consideration. I confess that, although certain authentic -anecdotes and certain experiments, to be described soon, lead me to -reject this exclusion, there are many qualities in animals’ behavior -which seem to back it up. If one takes his stand by a rigid application -of the law of parsimony, he will find justification for this view which -no experiments of mine can overthrow. - -Of one thing I am sure, and that is that it is worth while to state the -question and how to solve it, for although the point of view involved is -far removed from that of our leading psychologists to-day, it cannot long -remain so. I am sorry that I cannot pretend to give a final decision. - -The view seems preposterous because, if an animal has sense-impressions -when his brain is excited by currents starting in the end-organs, -it seems incredible that he should not be conscious in imagination -and memory by having similar excitations caused from within. We are -accustomed to think of memory as the companion of sensation. But, -after all, it is a question of fact whether the connections in the -cat brain include connections between present sensation-neuroses and -past sensation-neuroses. The only connections may be those between the -former and impulse-neuroses, and there is no authoritative reason why -we should suppose any others unless they are demonstrated by the cat’s -behavior. This is just the point at issue. Such evidence as the phenomena -of animals’ dreams does not at all prove the presence of memory or -imagination. A dog may very well growl in his sleep without any idea of -a hostile dog. The impulse to growl _may_ be caused by chance excitement -of its own neurosis without any sensation-neurosis being concerned. -_Acts_ of recognition may have no _feelings_ of recognition going with or -causing them. A sense-impression of me gets associated in my dog’s mind -with the impulses to jump on me, lick my hand, wag his tail, etc. If, -after a year, the connection between the two has lasted, he will surely -jump on me, lick my hand and wag his tail, though he has not and never -had any representation of me. - -The only logical way to go at this question and settle it is, I think, -to find some associations the formation of which requires the presence -of images, of ideas. You have to give an animal a chance to associate -sense-impression A with sense-impression B and then to associate B -with some act C so that the presence of B in the mind will lead to the -performance of C. Presumably the representation of B, if present, -will lead to C just as the sense-impression B did. Now, if the chance -to associate B with A has been improved, you ought, when the animal is -confronted with the sense-impression A, to get a revival of B and so -the act C. Such a result would, if all chance to associate C with A had -been eliminated, demonstrate the presence of representations and their -associations. I performed such an experiment in a form modified so as to -make it practicable with my animals and resources. Unfortunately, this -modification spoils the crucial nature of the experiment and robs it of -much of its authority. The experiment was as follows:— - -A cat was in the big box where they were kept (see p. 90) very hungry. -As I had been for a long time the source of all food, the cats had grown -to watch me very carefully. I sat, during the experiment, about eight -feet from the box, and would at intervals of two minutes clap my hands -four times and say, “I must feed those cats.” Of course the cat would at -first feel no impulse except perhaps to watch me more closely when this -signal was given. After ten seconds had elapsed I would take a piece of -fish, go up to the cage and hold it through the wire netting, three feet -from the floor. The cat would then, of course, feel the impulse to climb -up the front of the cage. In fact, experience had previously established -the habit of climbing up whenever I moved toward the cage, so that in the -experiment the cat did not ordinarily wait until I arrived there with the -fish. In this experiment - -A = The sense-impression of my movements and voice when giving the signal. - -B = The sense-impression of my movements in taking fish, rising, walking -to box, etc. - -C = The act of climbing up, with the impulse leading thereunto. - -The question was whether after a while A would remind the cat of B, and -cause him to do C before he got the _sense-impression_ of B, that is, -before the ten seconds were up. If A leads to C through a memory of B, -animals surely _can_ have association of ideas proper, and probably often -_do_. Now, as a fact, after from thirty to sixty trials, the cat does -perform C immediately on being confronted by A or some seconds later, -at all events before B is presented. And it is my present opinion that -their action is to be explained by the presence, through association, of -the idea B. But it is not impossible that A was associated _directly_ -with the impulse to C, although that impulse was removed from it by -ten seconds of time. Such an association is, it seems to me, highly -improbable, unless the neurosis of A, and with it the psychosis, -continues until the impulse to C appears. But if it does so continue -during the ten seconds, and thus get directly linked to C, we have -exactly a representation, an image, a memory, in the mind for eight of -those ten seconds. It does not help the deniers of images to substitute -an image of A for an image of B. Yet, unless they do this, they have -to suppose that A comes and goes, and that after ten seconds C comes, -and, passing over the intervening blank, willfully chooses out A and -associates itself with it. There are some other considerations regarding -the behavior of the cats from the time the signal was given till they -climbed up, which may be omitted in the hope that it will soon be -possible to perform a decisive experiment. If an observer can make sure -of the animal’s attention to a sequence A-B, where B does not arouse any -impulse to an act, and then later get the animal to associate B with C, -leaving A out this time, he may then, if A, when presented anew, arouses -C, bid the deniers of representations to forever hold their peace. - -Another reason for allowing animals representations and images is found -in the longer time taken to form the association between the act of -licking or scratching and the consequent escape. If the associations in -general were simply between situation and impulse and act, one would -suppose that the situation would be associated with the impulse to lick -or scratch as readily as with the impulse to turn a button or claw a -string. Such is not the case. By comparing the curves for Z on pages -57-58 with the others, one sees that for so simple an act it takes a -long time to form the association. This is not a final reason, for lack -of attention, a slight increase in the time taken to open the door after -the act was done, or an absence of preparation in the nervous system for -connections between these particular acts and definite sense-impressions, -may very well have been the cause of the difficulty in forming the -associations. Nor is it certain that _ideas_ of clawing loops would be -easier to form than ideas of scratching or licking oneself. The matter -is still open to question. But, as said before, my opinion would be that -animals _do_ have representations and that such are the beginning of the -rich life of ideas in man. For the most part, however, such are confined -to specific and narrow practical lines. There was no evidence that my -animals habitually _did_ form associations of ideas from their experience -throughout, or that such were constantly revived without the spur of -immediate practical advantage.[15] - -Before leaving the topic an account may be given of experiments similar -to the one described above as performed on Cats 3 and 4, which were -undertaken with Cat 13 and Dogs 1, 2 and 3. - -Cat 13 was fed with pieces of fish at the top of the wire netting 45 -times, to accustom it to climbing up when it saw me come with fish. I -then went through the same process as with 3 and 4, but at intervals of -60 to 90 seconds instead of 120. After 90 such trials it occasionally -climbed up a little way, but though 135 trials in all were given, it -never made the uniform and definite reaction which 3 and 4 did. It -reacted, when it reacted at all, at from 5 to 9 seconds after the -signal. Whether age, weight, lack of previous habitual climbing when I -approached, or a slowness in forming the association made the difference, -is uncertain. - -Dog 1 was experimented on in the following manner: I would put him in a -big pen, 20×10 feet, and sit outside facing it, he watching me as was -his habit. I would pound with a stick and say, “Go over to the corner.” -After an interval (10 seconds for 35 trials, 5 seconds for 60 trials) -I would go over to the corner (12 feet off) and drop a piece of meat -there. He, of course, followed and secured it. On the 6th, 7th, 16th, -17th, 18th and 19th trials he did perform the act before the 10 seconds -were up, then for several times went during the two-minute intervals -without regarding the signal, and finally abandoned the habit altogether, -although he showed by his behavior when the signal was given that he was -not indifferent to it. - -Dogs 1, 2 and 3 were also given 95, 135 and 95 trials, respectively, -the acts done being (1) standing up against the wire netting inclosing -the pen, (2) placing the paws on top of a keg, and (3) jumping up onto -a box. The time intervals were 5 seconds in each case. No dog of these -ever performed the act before I started to take the meat to feed them, -but they did show, by getting up if they were lying down when the signal -was given, or by coming to me if they were in some other part of the -pen, that something was suggested to them by it. Why these cases differ -from the cases of Cats 3 and 4 (10 and 12 also presented phenomena like -those reported in the cases of 3 and 4) is an interesting though not -very important question. The dogs were not kept so hungry as were the -cats, and experience had certainly not rendered the particular impulses -involved so sensitive, so ready to discharge. Dogs 2 and 3 were older. -There is no reason to invoke any qualitative difference in the mental -make-up of the animals until more illuminating experiments are made. - - -ASSOCIATION BY SIMILARITY AND THE FORMATION OF CONCEPTS - -What there is to say on this subject from the standpoint of my -experiments will be best introduced by an account of the experiments -themselves. - -Dog 1 had escaped from AA (O at front) 26 times. He was then put in -BB (O at back). Now, whereas 2 and 3, who were put in without previous -experience with AA, failed to paw the loop in BB, No. 1 succeeded. His -times were 7.00, .35, 2.05, .40, .32, .10, 1.10, .38, .10, .05, and from -then on he pawed the loop as soon as put in the box. After a day or so he -was put in BB1 (O at back high). Although the loop was in a new position, -his times were only .20, .10, .10, etc. After nine days he was put in a -box arranged with a little wooden platform 2½ inches square, hung where -the loop was in BB1. Although the platform resembled the loop not the -least save in position, his times were only .10, .07, .05, etc. - -[Illustration: FIG. 21.] - -From the curves given in Figure 21, which tell the history of 10, 11 and -12 in B1 (O at back) after each had previously been familiarized with A -(O at front), we see this same influence of practice in reacting to one -mechanism upon the time taken to react to a mechanism at all similar. It -naturally takes a cat a longer time to accidentally claw a loop in the -back than in the front, yet a comparison of these curves with those on -page 39, Figure 2, shows the opposite to have been the case with 10, 11 -and 12. The same remarkable quickness was noted in Cats 1 and 3 when put -into B (O at back) after learning A (O at front). Moreover, the loops -were not alike. The loop in A was of smaller wire, covered with a bluish -thread, while the loop in B was covered with a black rubber compound, the -diameter of the loop being three times that of A’s loop. - -If any advocate of reason in animals has read so far, I doubt not that -his heart has leaped with joy at these two preceding paragraphs. “How,” -he will say, “can you explain these facts without that prime factor in -human reason, association by similarity? Surely they show the animal -perceiving likenesses and acting from general ideas.” _This is the very -last thing that they show._ Let us see why they do not show this and what -they do show. He who thinks that these animals had a general notion of a -loop-like thing as the thing to be clawed, that they felt the loop in B, -different as it was in size, color and position, to be still a loop, to -have the essential quality of the other, must needs presuppose that the -cat has a clear, accurate sensation and representation of both. Only if -the cat discriminates can it later associate by noticing similarities. -This is what such thinkers do presuppose. A bird, for instance, dives -in the same manner into a river of yellow water, a pond or an ocean. -It has a general notion, they say, of water. It knows that river water -is one thing and pond water another thing, but it knows that both are -water, _ergo_, fit to dive into. The cat who reacts to a loop of small -wire of a blue color knows just what that loop is, and when it sees a -different loop, knows its differences, but knows also its likeness, and -reacts to the essential. Thus crediting the cat with our differentiation -and perception of individuality, they credit it with our conceptions and -perceptions of similarity. Unless the animal has the first, there is no -reason to suppose the last. Now, _the animal does not have either_. -It does not in the first place react to that particular loop in A, -with recognition of its qualities. It reacts to a vague, ill-defined -sense-impression, undiscriminated and even unperceived in the technical -sense of the word. Morgan’s phrase, “a bit of pure experience,” is -perhaps as good as any. The loop is to the cat what the ocean is to a -man, when thrown into it when half-asleep. Thus the cat who climbed up -the front of the cage whenever I said, “I must feed those cats,” would -climb up just as inevitably when I said, “My name is Thorndike,” or -“To-day is Tuesday.” So cats would claw at the loop or button when the -door was open. So cats would paw at the place where a loop had been, -though none was there. The reaction is not to a well-discriminated -object, but to a vague situation, and any element of the situation may -arouse the reaction. The whole situation in the case of man is speedily -resolved into elements; the particular elements are held in focus, and -the non-essential is systematically kept out of mind. In the animal the -whole situation sets loose the impulse; all of its elements, including -the non-essentials, get yoked with the impulse, and the situation may -be added to or subtracted from without destroying the association, -provided you leave something which will set off the impulse. The animal -does not think one is like the other, nor does it, as is so often said, -mistake one for the other. It does not think _about_ it at all; it just -thinks _it_, and the _it_ is the kind of “pure experience” we have -been describing. In human mental life we have accurate, discriminated -sensations and perceptions, realized as such, and general notions, also -realized as such. Now, what the phenomena in animals which we have been -considering show is that they have neither. Far from showing an advanced -stage of mentality, they show a very primitive and unspecialized stage. -They are to be explained not by the presence of _general_ notions, but by -the absence of notions of _particulars_. The idea that animals react to -a particular and absolutely defined and realized sense-impression, and -that a similar reaction to a sense-impression which varies from the first -proves an association by similarity, is a myth. We shall see later how an -animal does come in certain cases to discriminate, in one sense of the -word, with a great degree of delicacy, but we shall also see then what -must be emphasized now, that naturally the animal’s brain reacts very -coarsely to sense-impressions, and that the animal does not think about -his thoughts at all. - -This puts a new face upon the question of the origin and development of -human abstractions and consequent general ideas. It has been commonly -supposed that animals had ‘recepts’ or such semi-abstractions as Morgan’s -‘predominants,’ and that by associating with these, arbitrary and -permanent signs, such as articulate sounds, one turned them into genuine -ideas of qualities. Professor James has made the simple but brilliant -criticism that all a recept really means is _a tendency to react in a -certain way_. But I have tried to show that the fact that an animal -reacts alike to a lot of things gives no reason to believe that it is -conscious of their common quality and reacts to that consciousness, -because the things it reacts to in the first place are not the -hard-and-fast, well-defined ‘things’ of human life. What a ‘recept’ or -‘predominant’ really stands for is no thing which can be transformed into -a notion of a quality by being labelled with a name. This easy solution -of the problem of abstraction is impossible. A true idea of the problem -itself is better than such a solution. - -My statement of what has been the course of development along this line -is derived from observations of animals’ behavior and Professor James’ -theory of the nature of and presumable brain processes going with the -abstractions and conceptions of human consciousness, but it is justified -chiefly by its harmony with the view that conception, the faculty of -having general notions, has been naturally selected by reason of its -utility. The first thing is for an animal to learn to react alike only -to things which resemble each other in the _essential_ qualities. On an -artificial, analytic basis, feelings of abstract qualities might grow out -of reacting alike to objects similar in such a respect that the reaction -would be useless or harmful. But in the actual struggle for existence, -starting with the mammalian mind as we have found it, you will tend to -get reactions to the _beneficial_ similarities by selection from among -these so-called mistakes, _before you get any general faculty of noticing -similarities_. In order that this faculty of indifferent reaction to -different things shall grow into the useful faculty of indifferent -reaction to different things _which have all some quality that makes the -reaction a fit one_, there must be a tremendous range of associations. -For a lot of the similarities which are non-essential have to be stamped -out, not by a power of feeling likeness, but by their failure to lead to -pleasure. With such a wide range of associations we may get reactions -on the one hand where impulses have been connected with one particular -sense-impression because when connected with all others they had failed -to give pleasure, and on the other hand, reactions where an impulse has -been connected with numerous different impressions possessing one common -quality, and disconnected with all impressions, otherwise like these, -which fail to have that one quality. - -Combined with this multiplication of associations, there is, I think, an -equally important factor, the loosening of the elements of an association -from one another and from it as a whole. Probably the idea of the look -of the loop or lever or thumb latch never entered the mind of any one of -my cats during the months that they were with me, except when the front -end of the association containing it was excited by putting the cat -into the box. In general, the unit of their consciousness, apart from -impulses and emotions, is a whole association-series. Such soil cannot -grow general ideas, for the ideas, so long as they never show themselves -except for a particular practical business, will not be thought about -or realized in their nature or connections. If enough associations are -provided by a general curiosity, such as is seen among the monkeys, -if the mental elements of the association are freed, isolated, felt -by themselves, _then_ a realization of the ideas, feelings of their -similarity by transition from one to the other, feelings of qualities -and of meanings, may gradually emerge. Language will be a factor in the -isolation of the ideas and a help to their realization. But when any -one says that language has been the cause of the change from brute to -man, when one talks as if _nothing but it_ were needed to turn animal -consciousness into human, he is speaking as foolishly as one who should -say that a proboscis added to a cow would make it an elephant. - -This is all I have to say, in this connection, about association by -similarity and conception, and with it is concluded our analysis of the -nature of the association-process in animals. Before proceeding to treat -of the delicacy, complexity, number and permanence of these associations, -it seems worth while to attempt to describe graphically, not by analysis, -the mental fact we have been studying, and also to connect our results -with the previous theories of association. - -One who has seen the phenomena so far described, who has watched the -life of a cat or dog for a month or more under test conditions, gets, -or fancies he gets, a fairly definite idea of what the intellectual -life of a cat or dog feels like. It is most like what we feel when -consciousness contains little thought about anything, when we feel the -sense-impressions in their first intention, so to speak, when we feel our -own body, and the impulses we give to it. Sometimes one gets this animal -consciousness while in swimming, for example. One feels the water, the -sky, the birds above, but with no thoughts _about_ them or memories of -how they looked at other times, or æsthetic judgments about their beauty; -one feels no _ideas_ about what movements he will make, but feels himself -make them, feels his body throughout. Self-consciousness dies away. -Social consciousness dies away. The meanings, and values, and connections -of things die away. One feels sense-impressions, has impulses, feels the -movements he makes; that is all. - -This pictorial description may be supplemented by an account of some -associations in human life which are learned in the same way as are -animal associations; associations, therefore, where the process of -formation is possibly homologous with that in animals. When a man -learns to swim, to play tennis or billiards, or to juggle, the process -is something like what happens when the cat learns to pull the string -to get out of the box, provided, of course, we remove, in the man’s -case, all the accompanying mentality which is not directly concerned in -learning the feat.[16] Like the latter, the former contains desire, -sense-impression, impulse, act and possible representations. Like it, the -former is learned gradually. Moreover, the associations concerned cannot -be formed by imitation. One does not know how to dive just by seeing -another man dive. You cannot form them from being put through them, -though, of course, this helps indirectly, in a way that it does not with -animals. One makes use of no feelings of a common element, no perceptions -of similarity. The tennis player does not feel, “This ball coming at -this angle and with this speed is similar in angle, though not in speed, -to that other ball of an hour ago, therefore I will hit it in a similar -way.” He simply feels an impulse from the sense-impression. Finally, -the elements of the associations are not isolated. No tennis player’s -stream of thought is filled with free-floating representations of any of -the tens of thousands of sense-impressions or movements he has seen and -made on the tennis court. Yet there is consciousness enough at the time, -keen consciousness of the sense-impressions, impulses, feelings of one’s -bodily acts. So with the animals. There is consciousness enough, but of -this kind. - -Thus, the associations in human life, which compare with the simple -connections learned by animals, are associations involving connections -between novel, complex and often inconstant sense-impressions and -impulses to acts similarly novel, complex and often inconstant. Man has -the elements of most of his associations in isolated form, attended -to separately, possessed as a permanent fund, recallable at will, and -multifariously connected among themselves, but with these associations -which we have mentioned, and with others like them, he deals as the -animals deal with theirs. The process, in the man’s mind, leaving out -extraneous mental stuff, may be homologous to the association-process -in animals. Of course, by assiduous attention to the elements of these -associations, a man may isolate them, may thus get these associations -to the same plane as the rest. But they pass through the stage we have -described, even then, and with most men, stay there. The abstraction, the -naming, etc., generally come from observers of the game or action, and -concern things as felt by them, not by the participant. - - -CRITICISM OF PREVIOUS THEORIES - -We may now look for a moment at what previous writers have said about the -nature of association in animals. The complaint was made early in this -book that all the statements had been exceedingly vague and of no value, -except as retorts to the ‘reason’ school. In the course of the discussion -I have tried to extricate from this vagueness definite statements about -imitation, association of ideas, association by ideas. There is one more -theory, more or less hidden in the vagueness,—the theory that association -in animals is the same as association in man, that the animal mind -differs from the human mind only by the absence of reason and what it -implies. Presumably, silence about what association is, means that it is -the association which human psychology discusses. When the silence is -broken, we get such utterances of this theory as the following:— - -“I think we may say then that the higher animals are able to proceed a -long way in the formation and definition of highly complex constructs, -analogous to but probably differing somewhat from those which we form -ourselves. These constructs, moreover, through association with -reconstructs, or representations, link themselves in trains so that a -sensation, or group of sensations, may suggest a series of reconstructs, -or a series of remembered phenomena.” (C. L. Morgan, Animal Life and -Intelligence, p. 341.) - -“Lastly, before taking leave of the subject of the chapter, I am -most anxious that it should not be thought that, in contending that -intelligence is not reason, I wish in any way to disparage intelligence. -Nine tenths at least of the actions of average men are intelligent and -not rational. Do we not all of us know hundreds of practical men who are -in the highest degree intelligent, but in whom the rational, analytic -faculty is but little developed? Is it any injustice to the brutes to -contend that their inferences are of the same order as those of these -excellent practical folk? In any case, no such injustice is intended; -and if I deny them self-consciousness and reason, I grant to the higher -animals perceptions of marvelous acuteness and intelligent inferences of -wonderful accuracy and precision—intelligent inferences in some cases, -no doubt, more perfect even than those of man, who is often disturbed by -many thoughts” (_ibid._, pp. 376-377). - -“Language and the analytic faculty it renders possible differentiate man -from the brute” (_ibid._, p. 376). - -Here, as elsewhere, it should be remembered that Lloyd Morgan is not -quoted because he is the worst offender or because he represents the -opposite in general of what the present writer takes to be the truth. On -the contrary, Morgan is quoted because he is the least offender, because -he has taken the most advanced stand along the line of the present -investigation, because my differences from him are in the line of his -differences from other writers. With the theory of the passages just -quoted, however, which attribute extensive association of ideas and -general powers comparable to those of men minus reason, to the brutes, -and which repeat the time-honored distinction by language, I do not, in -the least, agree. Association in animals does not equal association in -man. The latter is built over and permeated and transformed by inference -and judgment and comparison; it includes imitation in our narrow sense -of transferred association; it obtains where no impulse is included; it -thus takes frequently the form of long trains of thought ending in no -pleasure-giving act; its elements are often loose, existing independently -of the particular association; the association is not only thought, -but at the same time thought _about_. None of these statements may -be truthfully made of animal association. Only a small part of human -association is at all comparable to it. My opinion of what that small -part is has already been given. Moreover, further differences will be -found as we consider the data relating to the delicacy, complexity, -number, and permanence of associations in animals. I said a while ago -that man was no more an animal with language than an elephant was a cow -with a proboscis. We may safely broaden the statement and say that _man -is not an animal plus reason_. It has been one great purpose of this -investigation to show that even after leaving reason out of account, -there are tremendous differences between man and the higher animals. -The problem of comparative psychology is not only to get human reason -from some lower faculties, but to get human _association_ from animal -association. - -Our analysis, necessarily imperfect because the first attempted, of the -nature of the association-process in animals is finished, and we have now -to speak of its limitations in respect to delicacy, complexity, number -and permanence. - - -DELICACY OF ASSOCIATIONS - -It goes without saying that the possible delicacy of associations is -conditioned by the delicacy of sense-powers. If an animal doesn’t feel -differently at seeing two objects, it cannot associate one with one -reaction, the other with another. An equally obvious factor is attention; -what is not attended to will not be associated. Beyond this there is no -_a priori_ reason why an animal should not react differently to things -varying only by the most delicate difference, and I am inclined to think -an animal could; that any two objects with a difference appreciable -by sensation which are also able to win attention may be reacted to -differently. Experiments to show this are very tedious, and the practical -question is, “What will the animal naturally attend to?” The difficulty, -as all trainers say, is to get the animal’s attention to your signal -somehow. Then he will in time surely react differently, if you give him -the chance, to a figure 7 on the blackboard from the way he does to a -figure 8, to your question, “How many days are there in a week?” and to -your question, “How many legs have you?” The chimpanzee in London that -handed out 3, 4, 5, 6, or 7 straws at command was not thereby proved of -remarkable intelligence or of remarkably delicate associative power. Any -reputable animal trainer would be ashamed to exhibit a horse who could -not do as much ‘counting’ as that. The maximum of delicacy in associating -exhibited by any animal, to my knowledge, is displayed in the performance -of the dog ‘Dodgerfield,’ exhibited by a Mr. Davis, who brings from four -cards, numbered 1, 2, 3 and 4, whichever one his master shall _think of_. -That is, you write out an arbitrary list, e.g. 4, 2, 1, 3, 3, 2, 2, 1, -4, 2, etc., and hand it to Mr. Davis, who looks at the list, thinks of -the first number, says “Attention! Dodger!” and then, “Bring it.” This -the dog does and so on through the list. Mr. Davis makes no signals which -anyone sitting even right beside or in front of him can detect. Thus the -dog exceeds the human observers in delicacy and associates each with -a separate act four attitudes of his master, which to human observers -seem all alike. Mr. Davis says he thinks the dog is a mind reader. I -think it quite possible that whatever signs the dog goes by are given -unconsciously and consist only of some very delicate general differences -in facial expression or the manner of saying the words, “Bring it,” or -slight sounds made by Mr. Davis in thinking to himself the words one or -two or three or four. Mr. Davis keeps his eyes shut and his hands behind -a newspaper. The dog looks directly at his face. - -To such a height possible delicacy may attain, but possible delicacy is -quite another thing from actual untrained and unstimulated delicacy. -The difference in reaction has to be brought about by associating with -pleasure the reaction to the different sense-impression when it itself -differs and associating with pain tendencies to confuse the reactions. -The animal does not naturally as a function of sense-powers discriminate -at all delicately. Thus the cat who climbed up the wire netting when -I said, “I must feed those cats!” did not have a delicate association -of just that act with just those words. For after I had dropped the -clapping part of the signal and simply used those words, it would react -just as vigorously to the words, “To-morrow is Tuesday” or “My name is -Thorndike.” The reaction naturally was to a very vague stimulus. Taking -cat 10 when just beginning to learn to climb up at the signal, “I must -feed those cats!” I started in to improve the delicacy, by opposing to -this formula the formula, “I will not feed them,” after saying which, I -kept my word. That is, I gave sometimes the former signal and fed the -cats, sometimes the latter and did not. The object was to see how long -the cat would be in learning always to go up when I gave the first, never -to do so when I gave the second signal. I said the words in both cases -as I naturally would do, so that there was a difference in emphasis and -tone as well as in the mere nature of the syllables. The two signals were -given in all sorts of combinations so that there was no regularity in the -recurrence of either which might aid the animal. The cat at first did not -always climb up at the first signal and often _did_ climb up at the wrong -one. The change from this condition to one of perfect discrimination is -shown in the accompanying curves (Fig. 22), one showing the decrease in -_failures_ to respond to the wrong signal. The first curve is formed by -a line joining the tops of perpendiculars erected at intervals of 1 mm. -along the abscissa. The height of a perpendicular represents the number -of times the cat failed to respond to the food-signal in 20 trials, a -height of 1 mm. being the representative of one failure. Thus, the entire -curve stands for 280 trials, there being no failures after 60 trials, and -only 1 after the 40th. - -[Illustration: FIG. 22.] - -In the other curve, also, each 1 mm. along the abscissa stands for 20 -trials, and the perpendiculars whose tops the curve unites represent the -number of times the cat in each 20 _did_ climb up at the signal which -meant no food. It will be seen that 380 experiences were necessary before -the animal learned that the second signal was different from the first. -The experiment shows beautifully the animal method of acquisition. If -at any stage the animal could have isolated the two ideas of the two -sense-impressions, and felt them together in comparison, this long and -tedious process would have been unnecessary. - -It might be stated here that the animals also acquired associations of -moderate delicacy in discriminating between the different boxes. No cat -tried to get out of A or B by licking herself, for instance. - -The question may naturally be raised that if naturally associations -are thus vague, the common phenomenon of a dog obeying his master’s -commands, and no one else’s, is inexplicable. The difference between -one man and another, one voice and another, it may be said, is not -much of a difference, yet is here uniformly discriminated, although we -cannot suppose any such systematic training to reject the other slightly -differing commands. My cats did not so discriminate. If any one else sat -in my chair and called out, “I must feed the cats,” they reacted, and -probably very many animals would, if untroubled by emotions of curiosity -or fear at the new individual, go through their tricks as well at -another’s voice as at that of their master. The other cases exemplify the -influence of attention. Repeated attention to these sense-impressions has -rendered them clear-cut and detailed, and the new impression consequently -does not equal them in calling forth the reaction. - -The main thing to carry away from this discussion is the assurance that -the delicacy of the animal in associating acts with impressions is -nothing like the delicacy of the man who feels that a certain tone is -higher, or weight is heavier, than another, but _is_ like the delicacy -of the man who runs to a certain spot to hit one tennis ball and to a -different spot to hit one coming with a slightly different speed. - - -COMPLEXITY OF ASSOCIATIONS - -An important question, especially if one wishes to rate an animal on a -scale of intelligence, is the question of how complex an association it -can form. A man can learn that to open a door he has to put the key in -its hole, turn it, turn the knob, and pull the door. Here, then, is a -complex act connected with the simple sense-impression. Or, conversely, -a man knows that when the ringing of a bell is followed by a whistle and -that by a red light he is to do a certain thing, while if any of the -three happens alone, he is not to. How far, then, we ask, can animals go -along the line of increased complexity in the associations? - -We must not mistake for a complex association a series of associations, -where one sense-impression leads to an act such as to present a new -sense-impression which leads to another act which in its turn leads to -a new sense-impression. Of the formation of such _series_ animals are -capable to a very high degree. Chicks from 10 to 25 days old learned to -go directly through a sort of big labyrinth requiring a series of 23 -distinct and in some cases fairly difficult associations, of which 11 -involved choices between two paths. By this power of acquiring a long -series animals find their way to distant feeding grounds and back again. -But all such cases are examples of the _number_, not of the complexity, -of animal associations. - -Some of my boxes were such as did give a chance for a complex association -to be formed. Such were G (thumb latch), J (double), K and L (triples) -for the cats, and O (triple) for the dogs. It would be possible for a -cat, after stepping on the platform in K, to notice that the platform was -in a different position, and so feel then a different sense-impression -from before, and thus turn the thing into a serial association. The -cat would then be like a man who on seeing a door should feel only the -impulse to stick the key in the hole, but then, seeing the door plus -a key in the hole, should feel the impulse to turn the key and so on -through. My cats did not give any signs of this, so that with them it -was either a complex association or an irregular happening of the proper -impulses. Probably the same was the case with Dog 1. Cats 10, 11, 12 in L -knew all the movements separately before being experimented on with the -combination. Cats 2, 3, 4 had had some experience of D, which worked by a -string something like the string part of K. The string in K was, however, -quite differently situated and required an altogether different movement -to pull it. Since further No. 2, who had had ten times as much experience -in D as 3 or 4, succeeded no better with the string element of K than -they, it is probable that the experience did not help very much. All else -in all these compound associations was new. At the same time the history -of these animals’ dealings with these boxes would not fairly represent -that of animals without general experience of clawing at all sorts of -loose or shaky things in the inside of a box. These cats had learned -to claw at all sorts of things. The time-curves were taken as in the -formation of the other associations, and, in addition, the order in which -the animal did the several things required was recorded in every trial. - -In the case of all the curves, except the latter part of 3 in G, one -notices a very gradual slope and an excessive irregularity in the curve -throughout. Within the limits of the trials given the animals are unable -to form a perfect association and what advancement they make is very -slow. The case of 3 in G is not an exception to this, but a proof of it. -For 3 succeeded in making a perfect association, by accidentally hitting -on a way to turn the compound association into a simple one. He happened -one time to paw down the thumb piece at the same time that his other fore -limb, with which he was holding on between the door and the top of the -box, was pressing against the door. This giving him success he repeated -it in later trials and in a short time had it fixed as an element in a -perfect association. The marked change in his curve, from an irregular -and gradual slope at such a height as displayed a very imperfect -association, to a constant and very slight height, shows precisely the -change from a compound to a simple association. - -Compound associations are formed slowly and not at all well. Further -observation shows that they were really not formed at all. For the -animals did not, except 3 in K for a certain period, do the several -things in a constant order, nor did they do them only once apiece. On the -contrary, an animal would pull the string several times after the bolt -had gone up with its customary click, and would do sometimes one thing -first, sometimes another. It may also be noted here, in advance of its -proper place, that these compound associations are far below the simple -in point of permanence. The conduct of the animals is clearly not that -of minds having associated with a certain box’s interior the idea of a -succession of three movements. The animal does not feel, “I did this and -that and that and got out,” or, more simply still, “this and that and -that means getting out.” If it did, we should soon see it doing what was -necessary without repetition and in a fairly constant time. - -I imagine, however, that an animal could learn to associate with one -sense-impression a compound act so as to perform its elements in a -regular order. By arranging the box so that the second and third elements -of the act could be performed _only after the first had been_, and the -third _only after the first and second_, I am inclined to think you -could get a very vigorous cat to learn the elements in order and form -the association perfectly. The case is comparable to that of delicacy. -The cat does not _tend_ to know what he is doing or to depart from the -hit-or-miss method of learning, but by associating the other combinations -of elements with failure to get pleasure, as in delicacy experiments we -associated the reactions to all but the one signal, you could probably -stamp out all but the 1, 2, 3 order. - -The fact that you have to thus maneuver to get the animals to have the -three impulses in a regular order shows that even when they are so, -there is no idea of the three as in an order, no thinking about them. -Representations do not get beyond their first intention. They are not -carried up into a free life which works them over anew. A complex _act_ -does not imply a complex _thought_, or, more exactly, a performance of a -series does not imply the thought of a series. Consequently, since the -complexity of the act depends on the power which failure has to stamp out -all other combinations, it is far more limited than in man. - - -NUMBER OF ASSOCIATIONS - -The patent and important fact is that there are so few in animals -compared to the human stock. Even after taking into account the various -acts associated with various smells, and exaggerating the possibility -of getting an equipment of associations in this field which man lacks, -one must recognize how far below man any animal is in respect to mere -quantity of associations. The associations with words alone of an -average American child of ten years far outnumber those of any dog. A -good billiard player probably has more associations in connection with -this single pastime than a dog with his whole life’s business. In the -associations which are homologous with those of animals man outdoes them -and adds an infinity of associations of a different sort. The primates -would seem, by virtue of their incessant curiosity and addition to -experience not for any practical purpose but merely for love of mental -life, to represent an advanced stage toward this tremendous quantity -of associations. In man not only this activity and curiosity, but also -education, increases the number of associations. Associations are -formed more quickly, and the absence of need for self-support during -a long infancy gives time. Associations thus formed work back upon -practical life, and by showing better ways decrease the need of work, -and so again increase the chance to form associations. The result in -the case of a human mind to-day is the possession of a thesaurus of -valuable associations, if the time has been wisely spent. The free life -of ideas, imitation, all the methods of communication, and the original -accomplishments which we may include under the head of invention, make -the process of acquisition in many cases quite a different one from the -trial and error method of the animals, and in general much shorten it. - -Small as it is, however, the number of associations which an animal may -acquire is probably much larger than popularly supposed. - -My cats and dogs did not mix up their acts with the wrong -sense-impressions. The chicks that learned the series of twenty-three -associations did not find it a task beyond their powers to retain -them. Several three-day-old chicks, which I caused to learn ten simple -associations in the same day, kept the things apart and on the next -morning went through each act at the proper stimulus. In the hands -of animal trainers some animals get a large number of associations -perfectly in hand. The horse Mascot is claimed to know the meaning of -fifteen hundred signals! He certainly knows a great many, and such as -are naturally difficult of acquisition. It would be an enlightening -investigation if some one could find out just how many associations a -cat or dog could form, if he were carefully and constantly given an -opportunity. The result would probably show that the number was limited -only by the amount of motive available and the time taken to acquire -each. For there is probably nothing in their brain structure which -limits the number of connections that can be formed, or would cause such -connections, as they grew numerous, to become confused. - -In their anxiety to credit animals with human powers, the psychologists -have disregarded or belittled, perhaps, the possibilities of the strictly -animal sort of association. They would think it more wonderful that a -horse should respond differently to a lot of different numbers on the -blackboard than that he should infer a consequence from premises. But -if it be made a direct question of pleasure or pain to an animal, he -can associate any number of acts with different stimuli. Only he does -not form any associations until he has to, until the direct benefit is -apparent, and, for his ordinary life, comparatively few are needed. - -On the whole our judgment from a comparison of man’s associations with -the brutes’ must be that a man’s are naturally far more delicate, -complex and numerous, and that in as far as the animals attain delicacy, -complexity, or a great number of associations, they do it by methods -which man uses only in a very limited part of the field. - - -PERMANENCE OF ASSOCIATIONS - -Once formed, the connections by which, when an animal feels a certain -sense-impression, he does a certain thing, persist over considerable -intervals of time. With the curves on pages 39 to 58 and 60 to 65 are -given in many instances[17] additional curves showing the animal’s -proficiency after an interval without experience. To these data may be -added the following:— - -The three chicks that had learned to escape through the long labyrinth -(involving twenty-three associations) succeeded in repeating the -performance after ten days’ interval. Similarly the chicks used as -imitators in V, W, X and Y did not fail to perform the proper act -after an interval of twenty days. Cat 6, who had had about a hundred -experiences in C (button), had the association as perfect after twenty -days as when it left off. Cat 2, who had had 36 experiences with C and -had attained a constant time of 8 seconds, escaped fourteen days later -in 3, 9 and 8 seconds, respectively, in three trials. Cat 1, after an -interval of twenty days, failed in 10 minutes to escape from C. The -signal for climbing up the front of the cage was reacted to by No. -3 after an interval of twenty-four days. No. 10, who had learned to -discriminate between ‘I must feed those cats’ and ‘I will not feed them,’ -was tried after _eighty_ days. It was given 50 trials with the second -signal mingled indiscriminately with 25 trials with the first. I give -the full record of these, ‘yes’ equalling a trial in which she ‘forgot’ -and climbed up, ‘no’ equalling a trial in which she wisely stayed down. -Dashes represent intervening trials with the first signal, _to which -she always reacted_. It will be observed that 50 trials put the cat in -the same position that 350 had done in her first experience, although in -that first experience she had had only about a hundred trials after the -association had been perfected. The association between the first signal -and climbing up was perfect after the eighty days. - - -TABLE 8 - - =======+========+========+========+========+======== - TRIALS | TRIALS | TRIALS | TRIALS | TRIALS | TRIALS - 1-7 | 8-17 | 18-27 | 28-35 | 36-42 | 43-50 - -------+--------+--------+--------+--------+-------- - — | yes | no | — | — | — - — | yes | yes | — | no | — - yes | yes | no | — | no | — - yes | — | no | no | — | — - no | yes | — | no | no | — - — | yes | — | yes | no | no - yes | no | yes | no | no | no - yes | yes | yes | — | — | yes - no | no | yes | no | — | no - no | — | yes | yes | no | no - — | — | no | no | no | no - — | yes | no | no | | no - — | yes | | | | no - | — | | | | - =======+========+========+========+========+======== - -All these data show that traces of the connections once formed are very -slow in being lost. If we allow that part of the time in the first trial -in all these cases is due to the time taken to realize the situation -(time not needed in the trials when the association is forming and the -animal is constantly being dropped into boxes), we may say that the -association is as firm as ever for a considerable time after practice -at it is stopped. How long a time would be required to annul the -influence of any given quantity of experience, say of an association -which had been gone through with ten times, I cannot say. It could, if -profitable, easily be determined in any case. The only case of total -loss of the association (No. 1 in C) is so exceptional that I fancy -something other than lapse of time was its cause. The main interest of -these data, considered as quantitative estimates, is not psychological, -but biological. They show what a tremendous advantage the well-developed -association-process is to an animal. The ways to different feeding -grounds, the actions of enemies, the appearance of noxious foods, are -all connected permanently with the proper reaction by a few experiences -which need be reënforced only very rarely. Of course, associations -without any permanence would be useless, but the usefulness increases -immensely with such a degree of permanence as these results witness. An -interesting experiment from the biological point of view would be to see -how infrequently an experience could occur and yet lead eventually to a -perfect association. An experiment approximating this is recorded in the -time-curves for Box H in Figure 7, on page 47. Three trials at a time -were given, the trials being two or three days apart. As may be seen from -the curves, the association was readily formed. - -The chief psychological interest of these data is that they show that -permanence of associations _is not memory_. The fact that a cat, when -after an interval she is put into box G, proceeds to immediately press -the thumb piece and push the door, does not at all mean that the cat -feels the box to be the same from which she weeks ago freed herself by -pushing down that thumb piece, or thinks about ever having felt or done -anything in that box. She does not refer the present situation to a -situation of the past and realize that it is the same, but simply feels -on being confronted with that situation the same impulse which she felt -before. She does the thing now for just the same reason that she did it -before, namely, because pleasure has connected that act above all others -with that sense-impression, so that it is the one she feels like doing. -Her condition is that of the swimmer who starts his summer season after -a winter’s deprivation. When he jumps off the pier and hits the water, -he swims, not because he remembers that this is the way he dealt with -water last summer and so applies his remembrance to present use, but just -because experience has taught him to feel like swimming when he hits the -water. All talk about recognition and memory in animals, if it asserts -the presence of anything more than this, is a gross mistake. For real -memory is an absolute thing, including everything but forgetfulness. If -the cat had real memory, it would, when after an interval dropped into -a box, remember that from this box it escaped by doing this or that and -consequently, either immediately or after a time of recollection, go -do it, or else it would not remember and would fail utterly to do it. -On the contrary, we have all grades of _partial_ ‘forgetfulness,’ just -like the grades of swimming one might find if he dropped a dozen college -professors into the mill ponds of their boyhood, just like the grades of -forgetfulness of the associations once acquired on the ball field which -are manifested when on the Fourth of July the ‘solid men’ of a town get -out to amuse their fellow citizens. The animal makes attacks on a spot -around the vital one, or claws at the thing—but not so precisely as -before, or goes at it a while and then resorts to instinctive methods of -getting out. Its actions are exactly what would be expected of an animal -in whom the sense-impression aroused the impulse imperfectly, or weakly, -or intermittently, but are not at all like the actions of one who felt, -“I used to get out of this box by pulling that loop down.” In fact, the -record of No. 10 given on page 139 seems to be final on this point. If -at any time in the course of the 50 trials it had _remembered_ that ‘I -will not feed them’ meant ‘no fish,’ it would thenceforth have failed -to react. It would have stopped short in the ‘yes’ reactions, instead -of gradually decreasing their percentage. ‘Memory’ in animals, if one -still chooses to use the word, is _permanence of associations_, not the -presence of an idea of an experience attributed to the past. - -To this proposition two corollaries may be added. First, these phenomena -of incomplete forgetfulness extend the evidence that animals do not have -a stock of independent ideas, the return of which, plus past associates, -equals memory. Second, there is, properly speaking, no continuity in -their mental streams. The present thought does not clutch the past to -its bosom or hold the future in its womb. The animal’s self is not a -being ‘looking before and after,’ but a direct practical association of -feelings and impulses. So far as experiences come continuously, they may -be said to form a continuous mental life, but there is no continuity -imposed from within. The feelings of its own body are always present, and -impressions from outside may come as they come to us. When the habit of -attending to the elements of its associations and raising them up into -the life of free ideas is acquired, these permanent bodily associations -may become the basis of a feeling of self-hood and the trains of ideas -may be felt as a continuous life. - - -INHIBITION OF INSTINCTS BY HABIT - -One very important result of association remains to be considered, its -inhibition of instincts and previous associations. An animal who has -become habituated to getting out of a box by pulling a loop and opening -the door will do so even though the hole in the top of the box be -uncovered, whereas, if, in early trials, you had left any such hole, he -would have taken the instinctive way and crawled through it. Instances of -this sort of thing are well-nigh ubiquitous. It is a tremendous factor -in animal life, and the strongest instincts may thus be annulled. The -phenomenon has been already recognized in the literature of the subject, -a convenient account being found in James’ ‘Psychology,’ Vol. II, pages -394-397. In addition to such accounts, one may note that the influence -of association is exerted in two ways. The instinct may wane by not -being used, because the animal forms the habit of meeting the situation -in a different way, or it may be actually inhibited. An instance of the -former sort is found in the history of a cat which learns to pull a loop -and so escape from a box whose top is covered by a board nailed over it. -If, after enough trials, you remove a piece of the board covering the -box, the cat, when put in, will still pull the loop instead of crawling -out through the opening thus made. But, at any time, if she happens to -notice the hole, she _may_ make use of it. An instance of the second -sort is that of a chick which has been put on a box with a wire screen -at its edge, preventing her from jumping directly down, as she would -instinctively do, and forcing her to jump to another box on one side -of it and thence down. In the experiments which I made, the chick was -prevented by a second screen from jumping directly from the second box -also. That is, if in the accompanying figure, A is a box 34 inches high, -B a box 25 inches high, C a box 16 inches high, and D the pen with the -food and other chicks, the subject had to go A-B-C-D. The chick tried at -first to get through the screen, pecked at it and ran up and down along -it, looking at the chicks below and seeking for a hole to get through. -Finally it jumped to B and, after a similar process, to C. After enough -trials it forms the habit and when put on A goes immediately to B, then -to C and down. Now if, after 75 or 80 trials, you take away the screens, -giving the chick a free chance to go to D from either A or B, and then -put it on A, the following phenomenon appears. The chick goes up to the -edge, looks over, walks up and down it for a while, still looking down -at the chicks below, and then goes and jumps to B as habit has taught it -to do. The same actions take place on B. No matter how clearly the chick -sees the chance to jump to D, it does not do so. The impulse has been -truly inhibited. It is not the mere habit of going the other way, but the -impossibility of going _that_ way. In one case I observed a chick in whom -the instinct was all but, yet not quite, inhibited. When tried without -the screen, it went up to the edge to look over _nine times_, and at -last, after seven minutes, did jump straight down. - -[Illustration: FIG. 23.] - - -ATTENTION - -I have presupposed throughout one function which it will be well to now -recognize explicitly, attention. As usual, attention emphasizes and -facilitates the process which it accompanies. Unless the sense-impression -is focussed by attention, it will not be associated with the act which -comes later. Unless two differing boxes are attended to, there will be -no difference in the reactions to them. The really effective part of -animal consciousness, then, as of human, is the part which is attended -to; attention is the ruler of animal as well as human mind. - -But in giving attention its deserts we need not forget that it is not -here comparable to the whole of human attention. Our attention to the -other player and the ball in a game of tennis _is_ like the animal’s -attention, but our attention to a passage in Hegel, or the memory which -flits through our mind, or the song we hear, or the player we idly watch, -is _not_. There ought, I think, to be a separate name for attention -when working for immediate practical associations. It is a different -species from that which holds objects so that we may define them, think -about them, remember them, etc., and the difference is, as our previous -sentence shows, not that between voluntary and involuntary attention. The -cat watching me for signs of my walking to the cage with fish is not in -the condition of the man watching a ball game, but in that of the player -watching the ball speeding toward him. There is a notable difference in -the permanence of the impression. The man watching the game can remember -just how that fly was hit and how the fielder ran for it, though he -bestowed only a slight quantity of attention on the matter, while the -fielder may attend to the utmost to the ball and yet not remember at all -how it came or how he ran for it. The one sort of attention leads you to -_think_ about a thing, the other to _act_ with reference to it. We must -be careful to remember that when we say that the cat attended to what was -said, we do not mean that he thereby established an idea of it. Animals -are not proved to form separate ideas of sense-impressions because they -attend to them, for the kind of attention they give is the kind which, -when given by men, results in practical associations, not in establishing -ideas of objects. If attention rendered clear the idea, we should not -have the phenomena of incomplete forgetfulness lately mentioned. The -animal would get a definite idea of just the exact thing done and would -do it or nothing. The human development of attention is in closest -connection with the acquisition of a stock of free ideas. - - -SOCIAL CONSCIOUSNESS - -Besides attention there is another topic somewhat apart from our general -one, which yet deserves a few words. It concerns animals’ social -consciousness, their consciousness of the feelings of their fellows. -Do animals, for example, when they see others feeding, feel that the -others are feeling pleasure? Do they, when they fight, feel that the -other feels pain? So level-headed a thinker as Lloyd Morgan has said that -they do, but the conduct of my animals would seem to show that they did -not. For it has given us good reason to suppose that they do not possess -_any_ stock of isolated ideas, much less any abstracted, inferred, or -transferred ideas. These ideas of others’ feelings imply a power to -transfer states felt in oneself to another and realize them as there. Now -it seems that any ability to thus transfer and realize an idea ought to -carry with it an ability to form a transferred association, to imitate. -If the animal realizes the mental states of the other animal who before -his eyes pulls the string, goes out through the door, and eats fish, -he ought to form the association, ‘impulse to pull string, pleasure of -eating fish.’ This we saw the animal could not do. - -In fact, pleasure in another, pain in another, is not a -sense-presentation or a representation or feeling of an object of any -sort, but rather a ‘meaning,’ a feeling ‘_of the fact that_.’ It can -exist only as something thought _about_. It is never ‘a bit of direct -experience,’ but an abstraction from our own life referred to that of -another. - -I fancy that these feelings of others’ feelings may be connected pretty -closely with imitation, and for that reason may begin to appear in the -monkeys. There we have some fair evidence for their presence in the -tricks which monkeys play on each other. Such feelings seem the natural -explanation of the apparently useless tail-pullings and such like which -make up the attractions of the monkey cage. These may, however, be -instinctive forms of play-activity or merely examples of the general -tendency of the monkeys to fool with everything. - - -INTERACTION - -I hope it will not be thought impertinent if from the standpoint of this -research I add a word about a general psychological problem, the problem -of interaction. I have spoken all along of the connection between the -situation and a certain impulse and act being stamped in when pleasure -results from the act and stamped out when it doesn’t. In this fact, -which is undeniable, lies a problem which Lloyd Morgan has frequently -emphasized. _How are pleasurable results able to burn in and render -predominant the association which led to them?_ This is perhaps the -greatest problem of both human and animal psychology. Unfortunately in -human psychology it has been all tangled up with the problems of free -will, mental activity, voluntary attention, the creation of novel acts, -and almost everything else. In our experiments we get the data which give -rise to the problem, in a very elementary form. - -It should first be noted about the _fact_ that the pleasure does not -burn in an impulse and act themselves, but an impulse and act _as -connected with that particular situation_. No cat ever goes around -clawing, clawing, clawing all the time, because clawing in these boxes -has resulted in pleasure. Secondly, the connection thus stamped in -is _not contemporaneous, but prior to_ the pleasure. So much for the -fact; now for the explanation. I do not wish to rehearse or add to the -arguments with which so many pages have been already filled by scientists -and philosophers both. What we need most is not argument, but accurate -accounts of the mental fact and of the brain-process. But I do wish to -say to the parallelist, what has not to my knowledge been said, that if -he presupposes, to account for this fact, a ‘physical analogue of the -hedonic consciousness,’ it is his bounden duty to first show how any -motion in any neurone or group of neurones in the nervous system can -possess this power of stamping in any current which causes it. For no one -would, from our present knowledge of the brain, judge _a priori_ that any -motion in any part of it could be conceived which should be thus regnant -over all the others. And next he must show the possibility of the current -which represents the association being the excitant of the regnant motion -in a manner direct enough for the purpose. - -I wish also to say that whoever thinks that, going along with the current -which parallels the association, there is an accompanying minor current, -which parallels the pleasure and which stamps in the first current when -present with it, flies directly in the face of the facts. _There is no -pleasure along with the association. The pleasure does not come until -after the association is done and gone._ It is caused by no such minor -current, but by the excitation of peripheral sense-organs when freedom -from confinement is realized or food is secured. Of course, the notion of -such a secondary subcurrent is mythology, anyway. - -To the interactionist I would say: “Do not any more repeat in tiresome -fashion that consciousness _does_ alter movement, but get to work and -show when, where, in what forms and to what degrees it does so. Then, -even if it turns out to have been a physical parallel that did the work, -you will, at least, have the credit of attaining the best knowledge about -the results and their conditions, even though you misnamed the factor.” - -Besides this contribution to general psychology, I think we may safely -offer one to pedagogical science. At least some of our results possess -considerable pedagogical interest. The fundamental form of intellection, -the association-process in animals, is one, we decided, which requires -the personal experience of the animal in all its elements. The -association cannot be taught by putting the animal through it or giving -it a chance to imitate. Now every observant teacher realizes how often -the cleverest explanation and the best models for imitation fail. Yet -often, in such cases, a pupil, if somehow enticed to do the thing, even -without comprehension of what it means, even without any real knowledge -of what he is doing, will finally get hold of it. So, also, in very -many kinds of knowledge, the pupil who does anything from imitation, or -who does anything from being put through it, fails to get a real and -permanent mastery of the thing. I am sure that with a certain type of -mind the only way to teach fractions in algebra, for example, is to get -the pupil to do, do, do. I am inclined to think that in many individuals -certain things cannot be learned save by actual performance. And I think -it is often a fair question, when explanation, imitation and actual -performance are all possible methods, which is the best. We are here -alongside the foundations of mental life, and this hitherto unsuspected -law of animal mind may prevail in human mind to an extent hitherto -unknown. The best way with children may often be, in the pompous words of -an animal trainer, ‘to arrange everything in connection with the trick -so that the animal will be compelled by the laws of his own nature to -perform it.’ - -This does not at all imply that I think, as a present school of -scientists seem to, that because a certain thing _has been_ in phylogeny -we ought to repeat it in ontogeny. Heaven knows that Dame Nature -herself in ontogeny abbreviates and skips and distorts the order of the -appearance of organs and functions, and for the best of reasons. We ought -to make an effort, as she does, to omit the useless and antiquated and -get to the best and most useful as soon as possible; we ought to change -what _is_ to what _ought to be_, as far as we can. And I would not -advocate this animal-like method of learning in place of the later ones -unless it does the same work better. I simply suggest that in many cases -where at present its use is never dreamed of, it may be a good method. -As the fundamental form of intellection, every student of _theoretical_ -pedagogy ought to take it into account. - -There is one more contribution, this time to anthropology. If the method -of trial and error, with accidental success, be the method of acquiring -associations among the animals, the slow progress of primitive man, -the long time between stone age and iron age, for instance, becomes -suggestive. Primitive man probably acquired knowledge by just this -process, aided possibly by imitation. At any rate, progress was not -by seeing through things, but by accidentally hitting upon them. Very -possibly an investigation of the history of primitive man and of the -present life of savages in the light of the results of this research -might bring out old facts in a new and profitable way. - -Comparative psychology has, in the light of this research, two tasks -of prime importance. One is to study the passage of the child mind from -a life of immediately practical associations to the life of free ideas; -the other is to find out how far the anthropoid primates advance toward -a similar passage, and to ascertain accurately what faint beginnings -or preparations for such an advance the early mammalian stock may be -supposed to have had. In this latter connection I think it will be -of the utmost importance to bear in mind the possibility that _the -present anthropoid primates may be mentally degenerate_. Their present -aimless activity and incessant, but largely useless, curiosity may be -the degenerated vestiges of such a well-directed activity and useful -curiosity as led _homo sapiens_ to important practical discoveries, -such as the use of tools, the art of making fire, etc. It is even a -remote possibility that their chattering is a _relic_ of something like -language, not a _beginning_ of such. Comparative psychology should use -the phenomena of the monkey mind of to-day to find out what the primitive -mind from which man’s sprung off was like. That is the important thing -to get at, and the question whether the present monkey mind has not gone -back instead of ahead is an all-important question. A natural and perhaps -sufficient cause of degeneracy would be arboreal habits. The animal that -found a means of survival in his muscles might well lose the means before -furnished by his brain. - -To these disconnected remarks still another must be added, addressed -this time to the anecdote school. Some member of it who has chanced to -read this may feel like saying: “This experimental work is all very -well. Your cats and dogs represent, it is true, specimens from the top -stratum of animal intelligence, and your negations, based on their -conduct, may be authoritative so far as concerns the average, typical -mammalian mind. But our anecdotes do not claim to be stories of the -conduct of the average or type, but of those exceptional individuals -who have begun to attain higher powers. And, if even a few dogs and -cats have these higher powers, our contention is, in a modified form, -upheld.” To all this I agree, provided the anecdote school now realize -just what sort of a position they hold. They are clearly in pretty much -the same position as spiritualists. Their anecdotes are on pretty much -the same level as the anecdotes of thought-transference, materializations -of spirits, supernormal knowledge, etc. Not in quite the same position, -for far greater care has been given by the Psychical Research Society to -establishing the criteria of authenticity, to insuring good observation, -to explaining by normal psychology all that can be so explained, in the -case of the latter than the anecdote school has done in the case of -the former. The off-hand explanation of certain anecdotes by invoking -reason, or imitation, or recognition, or feelings of qualities, is on a -par with the explanation of trance-phenomena and such like by invoking -the spirits of dead people. I do not deny that we may get lawfully a -supernormal psychology, or that the supernormal acts it finds may turn -out to be explained by these functions which I have denied to the normal -animal mind. But I must soberly declare that I think there is less -likelihood that such functions are the explanation of animal acts than -that the existence of the spirits of dead people is the true explanation -of the automatisms of spiritualistic phenomena. So much for the anecdote -school, if it calls itself by its right name and pretends only to give an -_abnormal_ animal psychology. The sad fact has been that it has always -pushed forward these exceptions as the essential phenomena of animal -mind. It has built up a general psychology from abnormal data. It is like -an anatomy written from observations on dime-museum freaks. - - -CONCLUSION - -I do not think it is advisable here, at the close of this paper, to give -a summary of its results. The paper itself is really only such a summary -with the most important evidence, for the extent of territory covered -and the need of brevity have prevented completeness in explanation or -illustration. If the reader cares here, at the end, to have the broadest -possible statement of our conclusions and will take the pains to supply -the right meaning, we might say that our work has described a method, -crude but promising, and has made the beginning of an exact estimate of -just what associations, simple and compound, an animal can form, how -quickly he forms them, and how long he retains them. It has described -the method of formation, and, on the condition that our subjects were -representative, has rejected reason, comparison or inference, perception -of similarity, and imitation. It has denied the existence in animal -consciousness of any important stock of free ideas or impulses, and so -has denied that animal association is homologous with the association of -human psychology. It has homologized it with a certain limited form of -human association. It has proposed, as necessary steps in the evolution -of human faculty, a vast increase in the number of associations, signs of -which appear in the primates, and a freeing of the elements thereof into -independent existence. It has given us an increased insight into various -mental processes. It has convinced the writer, if not the reader, that -the old speculations about what an animal could do, what it thought, and -how what it thought grew into what human beings think, were a long way -from the truth, and _not on the road to it_. - -Finally, I wish to say that, although the changes proposed in -the conception of mental development have been suggested somewhat -fragmentarily and in various connections, that has not been done because -I think them unimportant. On the contrary, I think them of the utmost -importance. I believe that our best service has been to show that -animal intellection is made up of a lot of specific connections, whose -elements are restricted to them, and which subserve practical ends -_directly_, and to homologize it with the intellection involved in such -human associations as regulate the conduct of a man playing tennis. The -fundamental phenomenon which I find presented in animal consciousness is -one which can harden into inherited connections and reflexes, on the one -hand, and thus connect naturally with a host of the phenomena of animal -life; on the other hand, it emphasizes the fact that our mental life has -grown up as a mediation between stimulus and reaction. The old view of -human consciousness is that it is built up out of elementary sensations, -that very minute bits of consciousness come first and gradually get built -up into the complex web. It looks for the beginnings of consciousness to -_little_ feelings. This our view abolishes and declares that the progress -is not from little and simple to big and complicated, but from direct -connections to indirect connections in which a stock of isolated elements -plays a part, is from ‘pure experience’ or undifferentiated feelings, to -discrimination, on the one hand, to generalizations, abstractions, on -the other. If, as seems probable, the primates display a vast increase -of associations, and a stock of free-swimming ideas, our view gives to -the line of descent a meaning which it never could have so long as the -question was the vague one of more or less ‘intelligence.’ It will, -I hope, when supported by an investigation of the mental life of the -primates and of the period in child life when these directly practical -associations become overgrown by a rapid luxuriance of free ideas, -show us the real history of the origin of human faculty. It turns out -apparently that a modest study of the facts of association in animals has -given us a working hypothesis for a comparative psychology. - - - - -CHAPTER III - -THE INSTINCTIVE REACTIONS OF YOUNG CHICKS[18] - - -The data to be presented in this article were obtained in the course of -a series of experiments conducted in connection with the psychological -laboratory of Harvard University during the year 1896-1897. About sixty -chicks were used as subjects. In general their experiences were entirely -under my control from birth. Where this was not true, the conditions of -their life previous to the experiments were known, and were such as would -have had no influence in determining the quality of their reactions in -the particular experiments to which they were subjected. It is not worth -while to recount the means taken so to regulate the chick’s environment -that his experience along certain lines should be in its entirety known -to the observer and that consequently his inherited abilities could be -surely differentiated. The nature of the experiments will, in most cases, -be such that little suspicion of the influence of education by experience -will be possible. In the other cases I will mention the particular means -then taken to prevent such influence. - -Some of my first experiments were on color vision in chicks from 18 to -30 hours old, just old enough to move about readily and to be hungry. On -backgrounds of white and black cardboard were pasted pieces of colored -paper about 2 mm. square. On each background there were six of these -pieces,—one each of yellow, red, orange, green, blue and black (on the -white ground) or white (on the black). They were in a row about half an -inch apart. The chicks had been in darkness for all but three or four -hours of their life so far. During those few hours the incubator had been -illuminated and the chicks had that much chance to learn color. - -The eight chicks were put, one at a time, on the sheet of cardboard -facing the colored spots. Count was kept of the number of times that they -pecked at each spot and, of course, they were watched to see whether they -would peck at all at random. In the experiments with the white background -all the colors were reacted to (_i.e._ pecked at) except black (but the -letters on a newspaper were pecked at by the same chicks the same day). -One of the chicks pecked at all five, one at four, three at three, one -at two and one at yellow only. These differences are due probably to -accidental position or movements. Taking the sums of the reactions to -each color-spot we get the following table:— - - -I - - =======+================+========================= - |TIMES REACTED TO|TOTAL NUMBER OF PECKS[19] - -------+----------------+------------------------- - Red | 12 | 31 - Yellow | 9 | 21 - Orange | 6 | 34 - Green | 5 | 11 - Blue | 1 | 3 - =======+================+========================= - -I should attach no importance whatever to the quantitative estimate given -in the table. The only fact of value so far is the evidence that from -the first the chick reacts to all colors. In no case was there any random -pecking at the white surface of the cardboard. - -On a black background the same chicks reacted to all the colors. - -II is a table of the results. - - -II - - =======+================+===================== - |TIMES REACTED TO|TOTAL NUMBER OF PECKS - -------+----------------+--------------------- - White | 6 | 19 - Blue | 4 | 11 - Red | 4 | 8 - Green | 4 | 4 - Orange | 2 | 7 - Yellow | 2 | 4 - -------+----------------+--------------------- - -In other experiments chicks were tried with green spots on a red ground, -red spots on a green ground, yellow spots on an orange ground, green -spots on a blue ground, and black spots on a white ground. All were -reacted to. Thus, what is apparently a long and arduous task to the -child is heredity’s gift to the chick. It is conceivable, though to me -incredible, that what the chick reacts to is not the color, but the very -minute elevation of the spot. My spots were made so that they were only -the thickness of thin paper above pasteboard. Any one who cares to resort -to the theory that this elevation caused the reaction can settle the case -by using color-spots absolutely level with the surface.[20] - - -INSTINCTIVE REACTIONS TO DISTANCE, DIRECTION, SIZE, ETC. - -I have purposely chosen this awkward heading rather than the simple -one, Space-Perception, because I do not wish to imply that there is in -the young chick such consciousness of space-facts as there is in human -beings. All that will be shown here is that he reacts appropriately in -the presence of space-facts, reacts in a fashion which would in the case -of a man go with genuine perception of space. - -If one puts a chick on top of a box in sight of his fellows below, the -chick will regulate his conduct by the height of the box. To be definite, -we may take the average chick of about 95 hours. If the height is less -than 10 inches, he will jump down as soon as you put him up. At 16 inches -he will jump in from 5 seconds to 3 or 4 minutes. At 22 inches he will -still jump down, but after more hesitation. At 27½ inches 6 chicks out -of eight at this age jumped within 5 minutes. At 39 inches the chick -_will NOT jump down_. The numerical values given here would, of course, -vary with the health, development, hunger and degree of lonesomeness of -the chick. All that they are supposed to show is that at any given age -the chick without experience of heights regulates his conduct rather -accurately in accord with the space-fact of distance which confronts -him. The chick does not peck at objects remote from him, does not, for -instance, confuse a bird a score of feet away with a fly near by, or try -to get the moon inside his bill. Moreover, he reacts in pecking with -considerable accuracy at the very start. Lloyd Morgan has noted that in -his very first efforts the chick often fails to seize the object, though -he hits it, and on this ground has denied the perfection of the instinct. -But, as a matter of fact, the pecking reaction may be as perfect at birth -as it is after 10 or 12 days’ experience. It certainly is not perfect -then. I took nine chicks from 10 to 14 days old and placed them one at -a time on a clear surface over which were scattered grains of cracked -wheat (the food they had been eating in this same way for a week) and -watched the accuracy of their pecking. Out of 214 objects pecked at, 159 -were seized, 55 _were not_. Out of the 159 that were seized, _only_ 116 -were seized on the first peck, 25 on the second, 16 on the third, and the -remaining two on the fourth. Of the 55 that were not successfully seized, -31 were pecked at only once, 10 twice, 10 three times, 3 four times and -1 five times. I fancy one would find that adult fowls would show by no -means a perfect record. So long as chicks with ten days’ experience fail -to seize on the first trial 45 per cent of the time, it is hardly fair to -argue against the perfection of the instinct on the ground of failures to -seize during the first day. - -The chick’s practical appreciation of space-facts is seen further in his -attempts to escape when confined. Put chicks only twenty or thirty hours -old in a box with walls three or four inches high and they will react to -the perpendicularity of the confining walls by trying to jump over them. -In fact, in the ways he moves, the directions he takes and the objects he -reacts to, the chicken has prior to experience the power of appropriate -reaction to colors and facts of all three dimensions. - - -INSTINCTIVE MUSCULAR COÖRDINATIONS - -In the acts already described we see fitting coördinations at work in -the chick’s reactions to space-facts. A few more samples may be given. -In jumping down from heights the chick does not walk off or fall off -(save rarely), but jumps off. He meets the situation “loneliness on a -small eminence” by walking around the edge and peering down; he meets -the situation “sight of fellow chicks below” by (after an amount of -hesitation varying roughly with the height) jumping off, holding his -stubby wings out and keeping right side up. He lands on his feet almost -every time and generally very cleverly. A four days’ chick will jump down -a distance eight times his own height without hurting himself a bit. If -one takes a chick two or three weeks old who has never had a chance to -jump up or down, and puts him in a box with walls three times the height -of the chick’s back, he will find that the chick will jump, or rather -fly, nearly, if not quite, over the wall, flapping his wings lustily -and holding on to the edge with his neck while he clambers over. Chicks -one day old will, in about 57 per cent of the cases, balance themselves -for five or six seconds when placed on a stiff perch. If eight or nine -days old, they will, though never before on any perch or anything like -one, balance perfectly for a minute or more. The muscular coördination -required is invoked immediately when the chick feels the situation “feet -on a perch.” The _strength_ is lacking in the first few days. From the -fifth or sixth day on chicks are also able (their ability increases with -age) to balance themselves on a slowly swinging perch. - -Another complex coördination is seen in the somewhat remarkable instinct -of swimming. Chicks only a day or two old will, if tossed into a pond, -head straight for the shore and swim rapidly to it. It is impossible to -compare their movements in so doing with those of ducklings, for the -chick is agitated, paddles his feet very fast and swims to get out, not -for swimming’s sake. Dr. Bashford Dean, of Columbia University, has -suggested to me that the movements may not be those of swimming, but only -of running. At all events, they are utterly different from those of an -adult fowl. In the case of the adult there is no vigorous instinct to -strike out toward the shore. The hen may try to fly back into the boat -if it is dropped overboard, and whether dropped in or slung in from the -shore, will float about aimlessly for a while and only very slowly reach -the shore. The movements the chick makes do look to be such as trying to -run in water might lead to, but it is hard to see why a hen shouldn’t run -to get out of cold water as well as a chick. If, on the other hand, the -actions of the chick are due to a real swimming instinct, it is easy to -see that, being unused, the instinct might wane as the animal grew up. - -Such instinctive coördinations as these, together with the walking, -running, preening of feathers, stretching out of leg backward, scratching -the head, etc., noted by other observers, make the infant chick a very -interesting contrast to the infant man. That the helplessness of the -child is a sacrifice to plasticity, instability and consequent power to -develop we all know; but one begins to realize how much of a sacrifice -when one sees what twenty-one days of embryonic life do for the chick -brain. And one cannot help wondering whether some of the space-perception -we trace to experience, some of the coördinations which we attribute to -a gradual development from random, accidentally caused movements may not -be more or less definitely provided for by the child’s inherited brain -structure. Walking has been found to be instinctive; why not other things? - - -INSTINCTIVE EMOTIONAL REACTIONS - -The only experiments to which I wish to refer at length under this -heading are some concerning the chick’s instinctive fears. Before -describing them, it may be well to mention their general bearing on -the results obtained by Spalding and Morgan. They corroborate Morgan’s -decision that no well-defined specific fears are present; that the fears -of young chicks are of strange moving objects in general, shock in -general, strange sounds in general. On the other hand, no such general -disturbances of the chick’s environment led to such well-marked reactions -as Spalding described. And so when Morgan thinks that such behavior as -Spalding witnessed on the part of the chick that heard the hawk’s cry -demands for its explanation nothing more than a general fear of strange -sounds, my experiments do not allow me to agree with him. If Spalding -really saw the conduct which he says the chick exhibited on the third -day of its life in the presence of man, and later at the stimulus of -the sight or sound of the hawk, there are specific reactions. For the -running, crouching, silence, quivering, etc., that one gets by yelling, -banging doors, tormenting a violin, throwing hats, bottles, or brushes -at the chick is never anything like so pronounced and never lasts one -tenth as long as it did with Spalding’s chicks. But, as to the fear of -man, Spalding must have been deluded. In the second, third and fourth -days there is no such reaction to the sight of man as he thought he saw. -Miss Hattie E. Hunt, in the _American Journal of Psychology_, Vol. IX., -No. 1, asserts that there is no instinctive fear of a cat. Morgan did -not find such. I myself put chicks of 2, 5, 9 and 17 days (different -individuals each time, 11 in all) in the presence of a cat. They showed -no fear, but went on eating as if there was nothing about. The cat was -still, or only slowly moving. I further put a young kitten (eight inches -long) in the pen with chicks. He felt of them with his paw, and walked -around among them for five or ten minutes, yet they showed no fear (nor -did he instinctively attack them). If, however, you let a cat jump at -chicks in real earnest, they will not stay to be eaten, but will manifest -fear—at least chicks three to four weeks old will. I did not try this -experiment with chicks at different ages, because it seemed rather cruel -and degrading to the experimenter. When in the case of the older chicks -nature happened to make the experiment, it was hard to decide whether -there was more violent fear of the jumping cat than there was when one -threw a basket or football into the pen. There was not very much more. - -We may now proceed to a brief recital of the facts shown by the -experiments in so far as they are novel. It should be remembered -throughout that in every case chicks of different ages were tested so as -to demonstrate transitory instincts if such existed, _e.g._, the presence -of a fear of flame was tested with chicks 59 and 60, one day old, 30 and -32, two days old, 21 and 22, three days old, 23 and 24, seven days old, -27 and 29, nine days old, 16 and 19, eleven days old, and so on up to -twenty-days-old chicks. By thus using different subjects at each trial -one, of course, eliminates any influence of experience. - -The first notable fact is that there develops in the first month a -general fear of novel objects in motion. For four or five days there -seems to be no such. You may throw a hat or slipper or shaving mug at a -chick of that age, and he will do no more than get out of the way of it. -But a twenty-five-days-old chick will generally chirr, run and crouch for -five or ten seconds. My records show this sort of thing beginning about -the tenth day, but it is about ten days more before it is very marked. -In general, also, the reaction is more pronounced if many chicks are -together, and is then displayed earlier (only two at a time were taken -in the experiments the results of which have just been quoted). Thus the -reaction is to some degree a social performance, the presence of other -chicks combining with the strange object to increase the vigor of the -reaction. Chicks ordinarily scatter apart when they thus run from an -object. - -One witnesses a similar gradual growth of the fear of man (not as such -probably, but merely as a large moving object). For four or five days -you can jump at the chick, grab at it with your hands, etc., without -disturbing it in the least. A chick twenty days old, however, although he -has never been touched or approached by a man, and in some cases never -seen one except as the daily bringer of food, and has never been in any -way injured by any large moving object of any sort, will run from you if -you try to catch him or even get very near him. There is, however, even -then, nothing like the utter fear described by Spalding. - -Up to thirty days there was no fear of a mocking bird into whose cage -the chicks were put, no fear of a stuffed hawk or a stuffed owl (kept -stationary). Chicks try to escape from water (even though warmed to the -temperature of their bodies) from the very first. Up to forty days there -appears no marked waning of the instinct. They did not show any emotional -reaction to the flame produced by six candles stuck closely together. -From the start they react instinctively to confinement, to loneliness, -to bodily restraint, but their feeling in these cases would better be -called discomfort than fear. From the 10th or 12th to the 20th day, and -probably later and very possibly earlier, one notices in chicks a general -avoidance of open places. Turn them out in your study and they will not -go out into the middle of the room, but will cling to the edges, go under -chairs, around table legs and along the walls. One sees nothing of the -sort up through the fourth day. Some experiments with feeding hive bees -to the chicks are interesting in connection with the following statement -by Lloyd Morgan: “One of my chicks, three or four days old, snapped up -a hive bee and ran off with it. Then he dropped it, shook his head much -and often, and wiped his bill repeatedly. I do not think he had been -stung: _probably he tasted the poison_” (‘Introduction to Comparative -Psychology,’ p. 86). I fed seven bees apiece to three chicks from ten to -twenty days old. _They ate them all greedily_, first smashing them down -on the ground violently in a rather dexterous manner. Apparently this -method of treatment is peculiar to the object. Chicks _three_ days old -did not eat the bees. Some pecked at them, but none would snap them up, -and when the bee approached, they sometimes sounded the danger note. - -Finally an account may be given of the reaction of chicks at different -ages, up to twenty-six days, to loud sounds. These were the sounds made -by clapping the hands, slamming a door, whistling sharply, banging a tin -pan on the floor, mewing like a cat, playing a violin, thumping a coal -scuttle with a shovel, etc. Two chicks were together in each experiment. -Three fourths of the times no effect was produced. On the other occasions -there was some running or crouching or, at least, starting to run or -crouch; but, as was said, nothing like what Spalding reports as the -reaction to the ‘cheep’ of the hawk. It is interesting to notice that -the two most emphatic reactions were to the imitation mew. One time a -chick ran wildly, chirring, and then crouched and stayed still until I -had counted 105. The other time a chick crouched and stayed still until I -counted 40. But the other chick with them did not; and in a dozen other -cases the ‘meaw’ had no effect. - -I think that the main interest of most of these experiments is the proof -they afford that instinctive reactions are not necessarily definite, -perfectly appropriate and unvarying responses to accurately sensed and, -so to speak, estimated stimuli. The old notion that instinct was a -God-given substitute for reason left us an unhappy legacy in the shape of -the tendency to think of all inherited powers of reaction as definite -particular acts invariably done in the presence of certain equally -definite situations. Such an act as the spider’s web-spinning might be -a stock example. Of course, there are many such instinctive reactions -in which a well-defined act follows a well-defined stimulus with the -regularity and precision with which the needle approaches the magnet. -But our experiments show that there are acts just as truly instinctive, -depending in just the same way on inherited brain-structure, but -characterized by being vague, irregular, and to some extent dissimilar, -reactions to vague, complex situations. - -The same stimulus doesn’t always produce just the same effect, doesn’t -produce precisely the same effect in all individuals. The chick’s -brain is evidently prepared in a general way to react more or less -appropriately to certain stimuli, and these reactions are among the most -important of its instincts or inherited functions. But yet one cannot -take these and find them always and everywhere. This helps us further to -realize the danger of supposing that in observation of animals you can -depend on a rigid uniformity. One would never suppose because one boy -twirled his thumb when asked a question that all boys of that age did. -But naturalists have been ready to believe that because one young animal -made a certain response to a certain stimulus, the thing was an instinct -common to all in precisely that same form. But a loud sound may make one -chick run, another crouch, another give the danger call, and another do -nothing whatever. - -In closing this article I may speak of one instinct which shows itself -clearly from at least as early as the sixth day, which is preparatory -to the duties of adult life and of no other use whatsoever. It is -interesting in connection with the general matter of animal play. The -phenomenon is as follows: The chicks are feeding quietly when suddenly -two chicks rush at each other, face each other a moment and then go about -their business. This thing keeps up and grows into the ordinary combat of -roosters. It is rather a puzzle on any theory that an instinct needed so -late should begin to develop so early. - - - - -CHAPTER IV - -A NOTE ON THE PSYCHOLOGY OF FISHES[21] - - -Numerous facts witness in a vague way to the ability of fishes to profit -by experience and fit their behavior to situations unprovided for by -their innate nervous equipment. All the phenomena shown by fishes as a -result of taming are, of course, of this sort. But such facts have not -been exact enough to make clear the mental or nervous processes involved -in such behavior, or simple enough to be available as demonstrations -of such processes. It seemed desirable to obtain evidence which should -demonstrate both the fact and the process of learning or intelligent -activity in the case of fishes and demonstrate them so readily that any -student could possess the evidence first hand. - -Through the kindness of the officials of the United States Fish -Commission at Woods Holl, especially of the director, Dr. Bumpus, I was -able to test the efficiency of some simple experiments directed toward -this end. The common Fundulus was chosen as a convenient subject, and -also because of the neurological interest attaching to the formation of -intelligent habits by a vertebrate whose forebrain lacks a cortex. - -The fishes studied were kept in an aquarium (about 4 feet long by 2 feet -wide, with a water depth of about 9 inches) represented by Fig. 24. The -space at one end, as represented by the lines in the figure, was shaded -from the sun by a cover, and all food was dropped in at this end. Along -each side of the aquarium were fastened simple pairs of cleats, allowing -the experimenter to put across it partitions of wood, glass or wire -screening. One of these in position is shown in the figure by the dotted -line. These partitions were made each with an opening, as shown in Fig. -25. If now we cause the fish to leave his shady corner and swim up to -the sunny end by putting a slide (without any opening) in behind him at -_D_ and moving it gently from _D_ to _A_ and then place, say slide _I_, -across the aquarium at 1, we shall have a chance to observe the animal’s -behavior to good purpose. - -[Illustration: FIG. 24.] - -[Illustration: FIG. 25.] - -This fish dislikes the sunlight and tries to get back to _D_. He reacts -to the situation in which he finds himself by swimming against the -screen, bumping against it here and there along the bottom. He may stop -and remain still for a while. He will occasionally rise up toward the -top of the water, especially while swimming up and down the length of -the screen. When he happens to rise up to the top at the right-hand end, -he has a clear path in front of him and swims to _D_ and feels more -comfortable. - -If, after he has enjoyed the shade fifteen minutes or more, you again -confine him in _A_, and keep on doing so six or eight times a day for a -day or so, you will find that he swims against the screen less and less, -swims up and down along it fewer and fewer times, stays still less and -less, until finally his only act is to go to the right-hand side, rise -up, and swim out. In correspondence with this change in behavior you will -find a very marked decrease in the time he takes to escape. The fish -has clearly profited by his experience and modified his conduct to suit -a situation for which his innate nervous equipment did not definitely -provide. He has, in common language, _learned_ to get out. - -This particular experiment was repeated with a number of individuals. -Another experiment was made, using three slides, _II_, _III_, and -another, requiring the fish to find his way from _A_ to _B_, _B_ to _C_, -and from _C_ to _D_. The results of these and still others show exactly -the same general mental process as does the one described—a process which -I have discussed at length elsewhere. - -Whatever interest there is in the demonstration in the case of the -bony fishes of the same process which accounts for so much of the -behavior of the higher vertebrates may be left to the neurologists. -The value of the experiment, if any, to most students will perhaps -be the extreme simplicity of the method, the ease of administering -it, and its possibilities. By using long aquaria, one can study the -formation of very complex series of acts and see to what extent any -fish can carry the formation of such series. By proper arrangements the -delicacy of discrimination of the fish in any respect may be tested. -The artificiality of the surroundings may, of course, be avoided when -desirable. - - - - -CHAPTER V - -THE MENTAL LIFE OF THE MONKEYS; AN EXPERIMENTAL STUDY[22] - - -The literary form of this monograph is not at all satisfactory to its -author. Compelled by practical considerations to present the facts -in a limited space, he has found it necessary to omit explanation, -illustration and many rhetorical aids to clearness and emphasis. For the -same reason detailed accounts of the administration of the experiments -have not always been given. In many places theoretical matters are -discussed with a curtness that savors of dogmatism. In general when a -theoretical point has appeared justified by the evidence given, I have, -to economize space, withheld further evidence. - -There is, however, to some extent a real fitness in the lack of -clearness, completeness and finish in the monograph. For the behavior of -the monkeys, by virtue of their inconstant attention, decided variability -of performance, and generally aimless, unforetellable conduct would be -falsely represented in any clean-cut, unambiguous, emphatic exposition. -The most striking testimony to the mental advance of the monkeys over -the dogs and cats is given by the difficulty of making clear emphatic -statements about them. - - -INTRODUCTION - -The work to be described in this paper is a direct continuation of -the work done by the author in 1897-1898 and described in Monograph -Supplement No. 8 of the _Psychological Review_ under the heading, ‘Animal -Intelligence; an Experimental Study of the Associative Processes in -Animals.’[23] This monograph affords by far the best introduction to the -present discussion, and I shall therefore assume an acquaintance with it -on the part of my readers. - -It will be remembered that evidence was there given that ordinary -mammals, barring the primates, did not infer or compare, did not imitate -in the sense of ‘learning to do an act from seeing it done,’ did not -learn various simple acts from being put through them, showed no signs -of having in connection with the bulk of their performances any mental -images. Their method of learning seemed to be the gradual selection of -certain acts in certain situations by reason of the satisfaction they -brought. Quantitative estimates of this gradualness were given for a -number of dogs and cats. Nothing has appeared since the ‘Experimental -Study’ to negate any of these conclusions in the author’s mind. The -work of Kline and Small[24] on rodents shows the same general aspect of -mammalian mentality. - -Adult human beings who are not notably deficient in mental functions, -at least all such as psychologists have observed, possess a large stock -of images and memories. The sight of a chair, for example, may call up -in their minds a picture of the person who usually sits in it, or the -sound of his name. The sound of a bell may call up the idea of dinner. -The outside world also is to them in large part a multitude of definite -percepts. They feel the environment as trees, sticks, stones, chairs, -tables, letters, words, etc. I have called such definite presentations -‘free ideas’ to distinguish them from the vague presentations such as -atmospheric pressure, the feeling of malaise, of the position of one’s -body when falling, etc. It is such ‘free ideas’ which compose the -substance of thought and which lead us to perhaps the majority of the -different acts we perform, though we do, of course, react to the vaguer -sort as well. I saw definitely in writing the last sentence the words -‘majority of the different acts’ and thought ‘we perform’ and so wrote -it. I see a bill and so take check book and pen and write. I think of the -cold outside and so put on an overcoat. This mental function ‘having free -ideas,’ gives the possibility of learning to meet situations properly -by thinking about them, by being reminded of some property of the fact -before us or some element therein. - -We can divide all learning into (1) _learning by trial and accidental -success_, by the strengthening of the connections between the -sense-impressions representing the situation and the acts—or impulses and -acts—representing our successful response to it and by the inhibition -of similar connections with unsuccessful responses; (2) _learning by -imitation_, where the mere performance by another of a certain act in a -certain situation leads us to do the same; and (3) _learning by ideas_, -where the situation calls up some idea (or ideas) which then arouses the -act or in some way modifies it. - -The last method of learning has obviously been the means of practically -all the advances in civilization. The evidence quoted a paragraph or so -back from the Experimental Study shows the typical mammalian mind to be -one which rarely or never learns in this fashion. The present study of -the primates has been a comparative study with two main questions in -view: (1) How do the monkeys vary from the other mammals in the general -mental functions revealed by their methods of learning? (2) How do they, -on the other hand, vary from adult civilized human beings? - -The experiments to be described seem, however, to be of value apart from -the possibility of settling crucial questions by means of the evidence -they give. To obtain exact accounts of what animals can learn by their -own unaided efforts, by the example of their fellows or by the tuition of -a trainer, and of how and how fast they learn in each case, seems highly -desirable. I shall present the results in the manner which fits their -consideration as arguments for or against some general hypotheses, but -the naturalist or psychologist lacking the genetic interest may find an -interest in them at their face value. I shall confine myself mainly to -questions concerning the method of learning of the primates, and will -discuss their sense-powers and unlearned reactions or instincts only in -so far as is necessary to its comprehension. - -It has been impossible for the author to make helpful use of the -anecdotes and observations of naturalists and miscellaneous writers -concerning monkey intelligence. The objections to such data pointed out -in Chapter II, pp. 22-26, hold here. Moreover it is not practicable to -sift out the true from the false or to interpret these random instances -of animal behavior even if assuredly true. In the study of animal life -the part is only clear in the light of the whole, and it is wiser to -limit conclusions to such as are drawn from the constant and systematic -study of a number of animals during a fairly long time. After a large -enough body of such evidence has been accumulated we may be able to -interpret random observations. - -The subjects of the experiments were three South American monkeys of the -genus _Cebus_. At the time of beginning the experiment No. 1 was about -half grown, No. 2 was about one fourth full size and No. 3 was about half -grown. No. 1 was under observation from November, 1899, to February, -1900; No. 2 and No. 3 from October, 1900, to February, 1901. No. 1 was -during the period of experimentation decidedly tame, showing no fear -whatever of my presence and little fear at being handled. He would handle -and climb over me with no hesitation. No. 2 was timid, did not allow -handling, but showed no fear of my presence and no phenomena that would -differentiate his behavior in the experiments discussed from that of No. -1, save much greater caution in all respects. No. 3 also showed no fear -at my presence. Any special individual traits that are of importance in -connection with any of the observations will be mentioned in their proper -places. No. 1 was kept until June, 1900, in my study in a cage 3 by 6 by -6 feet, and was left in the country till October, 1900. From October, -1900, all three were kept in a room 8 by 9 feet, in cages 6 feet tall by -3 long by 2.6 wide for Nos. 1 and 2, 3 feet by 3 feet by 20 inches for -No. 3. I studied their behavior in learning to get into boxes, the doors -to which could be opened by operating some mechanical contrivance, in -learning to obtain food by other simple acts, in learning to discriminate -between two signals, that is, to respond to each by a different act, and -in their general life. - -Following the order of the ‘Animal Intelligence,’ I shall first recount -the observations of the way the monkeys learned, solely by their own -unaided efforts, to operate simple mechanical contrivances. - -Besides a number of boxes such as were used with the dogs and cats (see -illustration on p. 30), I tried a variety of arrangements which could -be set up beside a cage, and which would, when some simple mechanism was -set in action, throw a bit of food into the cage. Figure 26 shows one of -these. See description of QQ (ff) on page 182. - -[Illustration: FIG. 26. _A_, loop; _BB_, lever, pivoted at _M_. A bit of -food put in front of _C_ would be thrown down the chute _DDD_ when _A_ -was released.] - - -APPARATUS - -The different mechanisms which I used were the following:— - -Box BB (O at back) was about 20 by 14 by 12 inches with a door in the -front which was held by a bolt to which was tied a string. This string -ran up the front of the box outside, over a pulley, across the top, and -over another pulley down into the box, where it ended in a loop of wire. - -Box MM (bolt) was the same as BB but with no string and loop attachment -to the bolt. - -Box CC (single bar) was a box of the same size as BB. The door was held -by a bar about 3 by 1 by 5 inches which swung on a nail at the left side. - -Box CCC (double bar) was CC with a second similar bar on the right side -of the door. - -Box NN (hook) was a box about the size of BB with its door held by an -ordinary hook on the left side which hooked through an eyelet screwed -into the door. - -Box NNN was NN with the hook on the right instead of the left side. - -Box NNNN was box NN with two hooks, one on each side. - -Apparatus OO (string box) consisted of a square box tied to a string, -which formed a loop running over a pulley by the cage and a pulley -outside, so that pulling on the under string would bring the box to the -cage. In each experiment the box was first pulled back to a distance of 2 -feet 3 inches from the cage, and a piece of banana put in it. The monkey -could, of course, secure the banana by pulling the box near enough. - -Apparatus OOO was the same as OO, with the box tied to the upper string, -so that the upper string had to be pulled instead of the lower. - -Box PP was about the size of BB. Its door was held by a large string -securely fastened at the right, passing across the front of the door and -ending in a loop which was put over a nail on the box at the left of the -door. By pulling the string off the nail the door could be opened. - -Box RR (wood plug) was a box about the size of BB. The door was held by -a string at its top, which passed up over the front and top to the rear, -where it was fastened to a wooden plug which was inserted in a hole in -the top of the box. When the plug was pulled out of the hole, the door -would fall open. - -Box SS (triple; wood-plug, hook and bar) was a box about the size of BB. -To open the door, a bar had to be pushed around, a hook unhooked and a -plug removed from a hole in the top of the box. - -Box TT (nail plug) was 14 by 10 by 10 inches with a door 5.5 by 10 on -the right side of the front, the rest of the front being barred up. The -door was hinged at the bottom and fastened at its top to a wire which -was fastened to a nail 2.5 inches long, which, when inserted in a hole -0.25 inches in diameter at the back of the top of the box, held the door -closed. By drawing out this nail and pulling the door the animal could -open the door. - -Box VV (plug at side) was a box about 18 by 10 by 10, the door held by -a plug passing through a hole in the side of the box. When the plug was -pulled out, the door could be pushed inward. - -Box W (loop) was 17 by 10 by 10 inches with a door 5 by 9 at the left -side of its front hinged at the bottom. The door was prevented from -falling inward by a wire stretched behind it. It was prevented from -falling outward by a wire firmly fastened at the right side and held by a -loop over a nail at the left. By pulling the loop outward and to the left -it could be freed from the nail. The door could then be pulled open. - -Box WW (bar inside) was 16 by 14 by 10 inches with a door 4 by 11 at the -left of its front hinged at the bottom. The door could be pushed in or -pulled out when a bar on its inside was lifted out of a latch. The bar -was accessible from the outside through an opening in the front of the -box. It had to be lifted to a height of 1.5 inches (an angle of about -30°). - -Box XX (bar outside) was about 13 by 11 by 10 inches with a door 7 by -8 on the left side of the front. The door was held in place by a bar -swinging on a nail at the top, with its other end resting in a latch at -the left side of the box. By pushing this up through an angle of 45° the -door could be opened. - -Box YY (push bar) was a box 16 by 8 by 12 inches with a door at the left -of its front. The door was held by a brass bar which swung down in front -of an L-shaped piece of steel fastened to the inside of the door. This -brass bar was hung on a pivot at its center and the other end attached -to a bar of wood; the other end of this bar projected through a hole at -the right side of the box. By pushing this bar in about an inch the door -could be opened. - -Box LL (triple; nail plug, hook and bar) was a box 10 by 10 by 13 with a -door 3 by 8.5 at the left side. The door could be opened only after (1) a -nail plug had been removed from a hole in the back of the top of the box -as in TT, (2) a hook in the door had been unhooked, and (3) a bar on the -left side had been turned from a horizontal to a vertical position. - -Box Alpha (catch at back) was 11 by 10 by 15 with the door (4 by 4) in -the left side of its front. The door was held by a bolt, which, when let -down, held in a catch on the inside of the door. A string fastened to the -bolt ran across to the back of the box and through a hole to the outside. -There it ended in a piece of wood 2.5 by 1 by .25 inches. When this piece -of wood was pulled, the bolt went up and the door fell open. - -Box Beta was the same as NN except in size. It was 10 by 10 by 13 inches. - -Box KK (triple; bolt, side plug, and knob) was a box 16 by 9 by 11 with -a door at the left side of the front. The door was held by a bolt on the -right side, a wooden plug stuck through a hole in the box on its left -side and a nail which held in a catch at its top. This nail was fastened -to a wooden knob (1 by 5 by .375) which lay in a depression at the top of -the box. Only when the bolt had been drawn and the plug and knob pulled, -could the door be opened. - -Box Gamma (wind) was 10 by 10 by 13 inches with its door held by a wire -fastened at the top and wound three times about a screw eye in the top of -the box. By unwinding the wire the door could be opened. - -Box Delta (push back) was 12 by 11 by 10 inches. Its door was held by -a wooden bar projecting from the right two inches in front of it. This -bar was so arranged that it could be pushed or pulled toward the right, -allowing the door to fall open. It could not be swung up or down. - -Box Epsilon (lever or push down) was 12 by 9 by 5 inches. At the right -side of its front was a hole ½ inch broad by 1½ inches up and down. -Across this hole on the inside of the box was a strip of brass, the end -of one bar of a lever. If this strip was depressed ⅛ of an inch, the door -at the extreme left would be opened by a spring. - -Box Zeta (side plug) was 12 by 11 by 10 inches. Its door was held by a -round bar of wood put through a hoop of steel at the left side of the -box. This bar was loose and could easily be pulled out, allowing the door -to be opened. - -Box Theta was the same as KK except that the door could be opened as soon -as the bolt alone was pulled or pushed up. - -Box Eta was like Alpha save that the object at the back of the box to be -pulled was a brass ring. - -Apparatus QQ (chute) consisted of a lever mechanism so arranged that -by pushing in a bar of wood ¼ to ½ an inch, a piece of banana would be -thrown down a chute into the cage. The apparatus was placed outside the -cage in such a way that it could be easily reached by the monkey’s arm -through the wire netting. - -QQ (a) was of the same general plan. By turning a handle through 270° -food could be obtained. - -QQ (b) was like QQ (a) except that 2½ full revolutions of the handle in -one direction were necessary to cause the food to drop down. - -QQ (c) was a chute apparatus so arranged as to work when a nail was -pulled out of a hole. - -QQ (d) was arranged to work at a sharp pull upon a brass ring hanging to -it. - -QQ (e) was arranged to work when a hook was unhooked. - -QQ (f) was arranged to work when a loop at the end of a string was pulled -off from a nail. - -QQ (ff) was QQ (f) with a stiff wire loop instead of a loop of string. - - -EXPERIMENTS ON THE ABILITIES OF THE MONKEYS TO LEARN WITHOUT TUITION - -I will describe a few of the experiments with No. 1 as samples and then -present the rest in the form of a table. No. 1 was tried first in BB (O -at back) on January 17, 1900, being _put inside_. He opened the box by -pulling up the string just above the bolt. His times were .05, 1.38, -6.00, 1.00, .10, .05, .05. He was not easily handled at this time, so I -changed the experiment to the form adopted in future experiments. I put -the food inside and left the animal to open the door from the outside. He -pulled the string up within 10 seconds each time out of 10 trials. - -I then tried him in MM (bolt). He failed in 15. I then (January 18th) -tried him in CC (single bar outside). He got in in 36.00 minutes; he did -not succeed a second time that night, but in the morning the box was -open. His times thenceforth were 20, 10, 16, 25 and on January 19th, 40, -5, 12, 8, 5, 5, 5 seconds. - -I then tried him (January 21, 1900) in CCC (double bar). He did it at -first by pushing the old bar and then pulling at the door until he worked -the second bar gradually around. Later he at times pushed the second -bar. The times taken are shown in the time-curve. I then (January 25th) -tried him in NN (hook). See time-curves on page 185. I then (January -27th) tried him in NNN (hook on other side). He opened it in 6, 12 and 4 -seconds in the first three trials. I then (20 minutes later) tried him -with NNNN (double hook). He opened the door in 12, 10, 6 and 6 seconds. I -then (January 27th) tried him with PP (string across). He failed in 10. -I then (February 21st) tried him with apparatus OO (string box). For his -progress as shown by the times taken see the time-curve. His progress is -also shown in the decrease of the useless pullings at the wrong string. -There were none in the 9th trial, 14th, 15th, 16th, 18th, 24th, and -following trials. - -No. 1 was then (February 24th) tried with OOO (string box with box on -upper string). No. 1 succeeded in 2.20, then failed in 10.00. The rest of -the experiment will be described under imitation. - -He was next tried (March 24th) with apparatus QQ (chute). He failed -in 10.00, though he played with the apparatus much of the time. Other -experiments were with box RR (wood-plug) (April 5th). He failed in 10.00. -After he had, in a manner to be described later, come to succeed with RR, -he was tried in box SS (triple; wood-plug, hook and bar) (April 18th); -see time-curve. No more experiments of this nature were tried until -October, 1900. - -The rest of the experiments with No. 1 and all those with No. 2 and No. -3 may best be enumerated in the form of a table. (See Table 9 on page -187.) It will show briefly the range of performances which the unaided -efforts of the animals can cope with. It will also give the order in -which each animal experienced them. F means that the animal failed to -succeed. The figures are minutes and seconds, and represent the time -taken in the first trial or the total time taken without success where -there is an F. In cases where the animal failed in say 10 minutes, but in -a later trial succeeded, say in 2.40, the record will be 2.40 after 10 F. -There are separate columns for all three animals, headed No. 1, No. 2 and -No. 3. Im. stands for a practically immediate success. - -The curves on pages 185 and 186 (Figs. 27 and 28) show the progress of -the formation of the associations in those cases where the animal was -given repeated trials, with, however, nothing to guide him but his own -unaided efforts. Each millimeter on the abscissa represents one trial -and each millimeter on the ordinate represents 10 seconds, the ordinates -representing the time taken by the animal to open the box. A break in -the curve, or an absence of the curve at the beginning of the base-line -represents cases where the animal failed in 10 minutes or took a very -long time to get out. - -[Illustration: FIG. 27.] - -[Illustration: FIG. 28.] - -In discussing these facts we may first of all clear our way of one -popular explanation, that this learning was due to ‘reasoning.’ If -we use the word reasoning in its technical psychological meaning as -the function of reaching conclusions by the perception of relations, -comparison and inference, if we think of the mental content involved as -feelings of relation, perceptions of similarity, general and abstract -notions and judgments, we find no evidence of reasoning in the behavior -of the monkeys toward the mechanisms used. And this fact nullifies the -arguments for reasoning in their case as it did in the case of the -dogs and cats. The argument that successful dealings with mechanical -contrivances imply that the animals reasoned out the properties of the -mechanisms, is destroyed when we find mere selection from their general -instinctive activities sufficient to cause success with bars, hooks, -loops, etc. There is also in the case of the monkeys, as in that of the -other mammals, positive evidence of the absence of any general function -of reasoning. We shall find that at least very many simple acts were not -learned by the monkeys in spite of their having seen me perform them -again and again; that the same holds true of many simple acts which they -saw other monkeys do, or were put through by me. We shall find that after -having abundant opportunity to realize that one signal meant food at the -bottom of the cage and another none, a monkey would not act from the -obvious inference and consistently stay up or go down as the case might -be, but would make errors such as would be natural if he acted under -the growing influence of an association between sense-impression and -impulse or sense-impression and idea, but quite incomprehensible if he -had compared the two signals and made a definite inference. We shall find -that, after experience with several pairs of signals, the monkeys yet -failed, when a new pair was used, to do the obvious thing to a rational -mind; viz., to compare the two, think which meant food, and act on the -knowledge directly. - - -TABLE 9 - - -------------------------------+---------------------------------+ - | No. 1. | - +-------------+---------+---------+ - | |Min. Sec.| | - -------------------------------+-------------+---------+---------+ - Box TT (nail plug) |Oct. 19, 1900| 0.40 | | - Box UU (old plug at side) |Oct. 19, 1900| | F 60.00| - Box VV (wire loop) |Oct. 20, 1900| |{ F 10.00| - | | |{ F 10.00| - | | |{ F 10.00| - Box WW (bar inside) |Oct. 20, 1900| | F 10.00| - | | | | - | | | | - | | | | - Box XX (bar outside) |Oct. 23, 1900| im. | after | - | | | [25] | - | | | F 10.00| - Box YY (push bar) |Oct. 30, 1900| 2.00[26]| | - Box Beta (single hook) | | | | - | | | | - | | | | - Box LL (triple; nail plug, |Nov. 4, 1900 |16.00[27]| | - hook and bar outside) | | | | - Box Alpha (catch at back) |Nov. 5, 1900 | .35 | | - Box KK (triple; bolt, side-plug|Nov. 7, 1900 | | F 10.00| - and knob) | | | F 10.00| - Box Theta (bolt at top) |Nov. 19, 1900| | F 10.00| - Box Eta (ring at back) |Dec. 17, 1900| im. | | - App. QQ (push chute) | | | | - Box Gamma (wind) |Jan. 3, 1901 | .20 | | - | | | | - Box Delta (push back) |Jan. 4, 1901 | | F 5.00| - | | | F 5.00| - App. QQ (a) (bar chute) |Jan. 6, 1901 | 8.00 | | - Box Zeta (new side plug) |Jan. 7, 1901 | 1.10 | after | - | | | F 5.00| - App. QQ (b) (2½ revolution | | | | - chute) |Jan. 9, 1901 | 3.00 | | - App. QQ (c) (nail-plug | | | | - chute) |Jan. 11, 1901| | F 5.00| - | | | F 5.00| - Box Epsilon (push down) |Jan. 12, 1901| | F 5.00| - | | | F 10.00| - App. QQ (d) (ring chute) |Jan. 16, 1901| | F 5.00| - | | | F 5.00| - App. QQ (e) (hook chute) | | | | - App. QQ (f) (string chute) |Jan. 17, 1901| | F 5.00| - App. QQ (ff) (string-wire |Jan. 17, 1901| .20 | | - chute) | | | | - -------------------------------+-------------+---------+---------+ - - -------------------------------+---------------------------------+ - | No. 2. | - +-------------+---------+---------+ - | |Min. Sec.| | - -------------------------------+-------------+---------+---------+ - Box TT (nail plug) |Oct. 21, 1900| 14.10 | | - Box UU (old plug at side) | | | | - Box VV (wire loop) |Oct. 24, 1900| | F 10.00| - |Oct. 25, 1900| | F 10.00| - | | | | - Box WW (bar inside) |Oct. 21, 1900| 5.00 | after| - | | | F 30.00| - | | | | - | | | | - Box XX (bar outside) |Oct. 24, 1900| 3.40 | | - | | | | - | | | | - Box YY (push bar) | | | | - Box Beta (single hook) |Oct. 30, 1900| 9.00 | after| - | | | F 10.00| - | | |and 10.00| - Box LL (triple; nail plug, |Oct. 3, 1900 | 2.00 | | - hook and bar outside) | | | | - Box Alpha (catch at back) |Oct. 5, 1900 | 6.00 | | - Box KK (triple; bolt, side-plug|Oct. 7, 1900 | | F 60.00| - and knob) | | | | - Box Theta (bolt at top) | | | | - Box Eta (ring at back) | | | | - App. QQ (push chute) | | | | - Box Gamma (wind) | | | | - | | | | - Box Delta (push back) | | | | - | | | | - App. QQ (a) (bar chute) | | | | - Box Zeta (new side plug) | | | | - | | | | - App. QQ (b) (2½ revolution | | | | - chute) | | | | - App. QQ (c) (nail-plug | | | | - chute) | | | | - | | | | - Box Epsilon (push down) | | | | - | | | | - App. QQ (d) (ring chute) | | | | - | | | | - App. QQ (e) (hook chute) | | | | - App. QQ (f) (string chute) | | | | - App. QQ (ff) (string-wire | | | | - chute) | | | | - -------------------------------+-------------+---------+---------+ - - -------------------------------+---------------------------------- - | No. 3. - +-------------+---------+---------- - | |Min. Sec.| - -------------------------------+-------------+---------+---------- - Box TT (nail plug) |Oct. 21, 1900| 36.00 | - Box UU (old plug at side) | | | - Box VV (wire loop) |Oct. 22, 1900| |{ F 10.00 - | | |{ F 10.00 - | | |{ F 10.00 - Box WW (bar inside) |Oct. 22, 1900| |{ F 10.00 - |Oct. 24, 1900| |{ F 5.00 - | | |{ F 10.00 - | | |{ F 15.00 - Box XX (bar outside) |Oct. 23, 1900| .30 | - | | | - | | | - Box YY (push bar) | | | - Box Beta (single hook) |Oct. 24, 1900| im. | - | | | - | | | - Box LL (triple; nail plug, |Nov. 3, 1900 | 1.45 | - hook and bar outside) | | | - Box Alpha (catch at back) |Nov. 5, 1900 | | - Box KK (triple; bolt, side-plug|Nov. 7, 1900 | | F 10.00 - and knob) | | | - Box Theta (bolt at top) |Jan. 8, 1901 | | F 10.00 - Box Eta (ring at back) |Dec. 17, 1900| 4.20 | - App. QQ (push chute) |Dec. 17, 1900| | F 60.00 - Box Gamma (wind) |Jan. 4, 1901 | | F 10.00 - | | | F 10.00 - Box Delta (push back) |Jan. 4, 1901 | 2.10 |after[28] - | | | F 10.00 - App. QQ (a) (bar chute) |Jan. 7, 1901 | | F 10.00 - Box Zeta (new side plug) |Jan. 8, 1901 | .50 | - | | | - App. QQ (b) (2½ revolution | | | - chute) |Jan. 8, 1901 | | F 10.00 - App. QQ (c) (nail-plug | | | - chute) |Jan. 11, 1901| | F 5.00 - | | | F 5.00 - Box Epsilon (push down) |Jan. 12, 1901| | F 10.00 - | | | - App. QQ (d) (ring chute) |Jan. 16, 1901| im. | - | | | - App. QQ (e) (hook chute) |Jan. 16, 1901| | F 5.00 - App. QQ (f) (string chute) | | | - App. QQ (ff) (string-wire |Jan. 19, 1901| | F 5.00 - chute) | | | F 5.00 - -------------------------------+-------------+---------+---------- - -The methods one has to take to get them to do anything, their general -conduct in becoming tame and in the experiments throughout, confirm -these conclusions. The following particular phenomena are samples of the -many which are inconsistent with the presence of reasoning as a general -function. No. 1 had learned to open a door by pushing a bar around from -a horizontal to a vertical position. The same box was then fitted with -two bars. He turned the first bar round thirteen times before attempting -to push the other bar around. In box LL all three monkeys would in the -early trials do one or two of the acts over and over after they had once -done them. No. 1, who had learned to pull a loop of wire off from a nail, -failed thereafter to pull off a similar loop made of string. No. 1 and -No. 3 had learned to poke their left hands through the cage for me to -take and operate a chute with. It was extremely difficult to get either -of them to put his right hand through or even to let me take it and pull -it through. - -A negative answer to the question “Do the monkeys reason?” thus -seems inevitable, but I do not attach to the question an importance -commensurate with the part it has played historically in animal -psychology. For I think it can be shown, and I hope in a later monograph -to show, that reasoning is probably but one secondary result of the -general function of having free ideas in great numbers, one product of a -type of brain which works in great detail, not in gross associations. The -denial of reasoning need not mean, and does not to my mind, any denial -of continuity between animal and human mentality or any denial that the -monkeys are mentally nearer relatives to man than are the other mammals. - -So much for supererogatory explanation. Let us now turn to a more -definite and fruitful treatment of these records. - -The difference between these records and those of the chicks, cats and -dogs given on pages 39-65 _passim_ is undeniable. Whereas the latter -were practically unanimous, save in the cases of the very easiest -performances, in showing a process of gradual learning by a gradual -elimination of unsuccessful movements, and a gradual reënforcement of -the successful one, these are unanimous, save in the very hardest, in -showing a process of sudden acquisition by a rapid, often apparently -instantaneous, abandonment of the unsuccessful movements and a selection -of the appropriate one which rivals in suddenness the selections made by -human beings in similar performances. It is natural to infer that the -monkeys who suddenly replace much general pulling and clawing by a single -definite pull at a hook or bar have an idea of the hook or bar and of the -movement they make. The rate of their progress is so different from that -of the cats and dogs that we cannot help imagining as the cause of it a -totally different mental function, namely, free ideas instead of vague -sense-impressions and impulses. But our interpretation of these results -should not be too hasty. We must first consider several other possible -explanations of the rapidity of learning by the monkeys before jumping to -the conclusion that the forces which bring about the sudden formation of -associations in human beings are present. - -First of all it might be that the difference was due to the superiority -of the monkeys in clear detailed vision. It might be that in given -situations where associations were to be formed on the basis of smells, -the cats and dogs would show similar rapid learning. There might be, -that is, no general difference in type of mental functioning, but only -a special difference in the field in which the function worked. This -question can be answered by an investigation of the process of forming -associations in connection with smells by dogs and cats. Such an -investigation will, I hope, soon be carried on in the Columbia Laboratory -by Mr. Davis.[29] - -Secondly, it might be that the superior mobility and more detailed -and definite movements of the monkeys’ hands might have caused the -difference. The slowness in the case of the dogs and cats might be at -least in part the result of difficulty in executing movements, not in -intending them. This difficulty in execution is a matter that cannot be -readily estimated, but the movements made by the cats and dogs would -not on their face value seem to be hard. They were mostly common to the -animals’ ordinary life. At the same time there were certain movements -(_e.g._ depressing the lever) which were much more quickly associated -with their respective situations by the cats than others were, and if -we could suppose that all the movements learned by the monkeys were -comparable to these few, it would detract from the necessity of seeking -some general mental difference as the explanation of the difference in -the results. - -In the third place it may be said by some that no comparison of the -monkeys with dogs and cats is valid, since the former animals got out of -boxes while the latter got in. It may be supposed that the instinctive -response to confinement includes an agitation which precludes anything -save vague unregulated behavior. Professor Wesley Mills has made -such a suggestion in referring to the ‘Animal Intelligence’ in the -_Psychological Review_, May, 1899. In the July number of the same journal -I tried to show that there was no solid evidence of such a harmful -agitation. Nor can we be at all sure that agitation when present does not -rather quicken the wits of animals. It often seems to. However I should, -of course, allow that for purposes of comparison it would be better to -have the circumstances identical. And I should welcome any antagonist who -should, by making experiments with kittens after the fashion of these -with the monkeys, show that they did learn as suddenly as the latter. - -Again we know that, whereas the times taken by a cat in a box to get -out are inversely proportional to the strength of the association, -inasmuch as they represent fairly the amount of its efforts, on the -other hand, the times taken by a monkey to get in represent the amounts -of his efforts _plus the amount of time in which he is not trying to -get in_. It may be said therefore that the time records of the monkeys -prove nothing,—that a record of four minutes may mean thirty seconds of -effort and three minutes thirty seconds of sleep,—that one minute may -really represent twice as much effort. As a matter of fact this objection -would occasionally hold against some single record. The earliest times -and the occasional long times amongst very short ones are likely to be -too long. The first fact makes the curves have too great a drop at the -start, making them seem cases of too sudden learning, but the second fact -makes the learning seem indefinite when it really is not. And in the long -run the times taken do represent fairly well the amount of effort. I -carefully recorded the amount of actual effort in a number of cases and -the story it tells concerning the mental processes involved is the same -as that told by the time-curves. - -Still another explanation is this: The monkeys learn quickly, it is true, -but not quickly enough for us to suppose the presence of ideas, or the -formation of associations among them. For if there were such ideas, they -should in the complex acts do even better than they did. The explanation -then is a high degree of facility in the formation of associations of -just the same kind as we found in the chicks, dogs and cats. - -Such an explanation we could hardly disapprove in any case. No one can -from objective evidence set up a standard of speed of learning below -which all shall be learning without ideas and above which all shall be -learning by ideas. We should not expect any hard and fast demarcation. - -This whole matter of the rate of learning should be studied in the light -of other facts of behavior. My own judgment, if I had nothing but these -time-curves to rely on, would be that there was in them an appearance of -learning by ideas which, while possibly explicable by the finer vision -and freer movements of the monkey in connection with ordinary mammalian -mentality, made it worth while to look farther into their behavior. This -we may now do. - -What leads the lay mind to attribute superior mental gifts to an animal -is not so much the rate of learning as the amount learned. The monkeys -obviously form more associations and associations in a greater variety -than do the other mammals. The improved rate assists, but another cause -of this greater number of associations is the general physical activity -of the monkeys, their constant movements of the hands, their instinctive -curiosity or tendency to fool with all sorts of objects, to enjoy having -sense-impressions, to form associations because of the resulting sound or -sight. These mental characteristics are of a high degree of importance -from the comparative point of view, but they cannot be used to prove that -the monkeys have free ideas, for a large number of associations may be -acquired after the purely animal fashion. - -What is of more importance is the actual behavior of the animals in -connection with the boxes. First of all, as has been stated, all the -monkey’s movements are more definite, he seems not merely to pull, but -to pull at, not merely to poke, but to push at. He seems, even in his -general random play, to go here and there, pick up this, examine the -other, etc., more from having the idea strike him than from feeling like -doing it. He seems more like a man at the breakfast table than like a man -in a fight. Still this appearance may be quite specious, and I think it -is likely to lead us to read ideational life into his behavior if we are -not cautious. It may be simply general activity of the same sort as the -narrower activities of the cat or dog. - -In the second place the monkeys often make special movements with a -directness which reminds one unavoidably of human actions guided by -ideas. For instance, No. 1 escaped from his cage one day and went -directly across the room to a table where lay a half of a banana which -was in a very inconspicuous place. It seemed as if he had observed the -banana and acted with the idea of its position fully in mind. Again, on -failing to pull a hook out, No. 1 immediately applied his teeth, though -he had before always pulled it out with his hand. So again with a plug. -It may be that there is a special inborn tendency to bite at objects -pulled unsuccessfully. If not, the act would seem to show the presence of -the idea ‘get thing out’ or ‘thing come out’ and associated with it the -impulse to use the teeth. We shall see later, however, that in certain -other circumstances where we should expect ideas to be present and result -in acts they do not. - -The fact is that those features in the behavior of the monkeys in forming -associations between the sight of a box and the act needed to open it -which remind us of learning by ideas may also be possibly explained by -general activity and curiosity, the free use of the hand, and superior -quickness in forming associations of the animal sort. We must have -recourse to more crucial tests or at least seek evidence from a number of -different kinds of mental performances. The first of these will naturally -be their behavior toward these same mechanisms after a long time-interval. - - -THE PERMANENCE OF ASSOCIATIONS IN THE CASE OF MECHANISMS - -My records are too few and in all but one case after too short an -interval to be decisive on the point of abrupt transition from failure -to success such as would characterize an animal in whose mind arose the -idea of a certain part of the mechanism as the thing to be attacked or of -a certain movement as the fit one. The animals are all under observation -in the Columbia Laboratory, however, and I trust that later satisfactory -tests may be made. No. 2 was not included in the tests because he was -either unwell or had become very shy of the boxes, entering them even -when the door was left open only after great delay. The time-curves for -the experiments performed will be found on page 186 among the others. The -figures beside each pair represent the number of days without practice. - -The records show a decided superiority to those of the cats and dogs. -Although the number of trials in the original tests were in general fewer -in the case of the monkeys, the retention of the association is complete -in 6 cases out of 8 and is practically so in one case where the interval -was 8 months. - - -EXPERIMENTS ON THE DISCRIMINATION OF SIGNALS - -My experiments on discrimination were of the following general type: I -got the animal into the habit of reacting to a certain signal (a sound, -movement, posture, visual presentation or what not) by some well-defined -act. In the cases to be described this act was to come down from his -customary positions about the top of the cage, to a place at the bottom. -I then would give him a bit of food. When this habit was wholly or -partly formed, I would begin to mix with that signal another signal -enough like it so that the animal would respond in the same manner. In -the cases where I gave this signal I would not feed him. I could then -determine whether the animal did discriminate or not, and his progress -toward perfect discrimination in case he did. If an animal responds -indiscriminately to both signals (that is, does not learn to disregard -the ‘no food’ signal) it is well to test him by using two somewhat -similar signals, after one of which you feed him at one place and after -the other of which you feed him at a different place. - -If the animal profits by his training by acquiring ideas of the two -signals and associates with them ideas of ‘food’ and ‘no food,’ ‘go -down’ and ‘stay still,’ and uses these ideas to control his conduct, he -will, we have a right to expect, change suddenly from total failure to -differentiate the signals to total success. He will or won’t have the -ideas, and will behave accordingly. The same result could, of course, be -brought about by very rapid association of the new signal with the act -of keeping still, a very rapid inhibition of the act of going down in -response to it by virtue of the lack of any pleasure from doing so. - -For convenience I shall call the signals after which food was given _yes_ -signals and those after which food was not given _no_ signals. Signals -not described in the text are shown in Fig. 29, below. The progress of -the monkeys in discriminating is shown by Figs. 30 and 31, on pages 199 -and 201. In Figs. 30 and 31 every millimeter along the horizontal or -base line represents 10 trials with the signal. The heights of the black -surface represent the percentages of _wrong_ responses, 10 mm. meaning -100 per cent of incorrect responses. Thus the first figure of the set, -Left hand, _a_, presents the following record: First 10 trials, all -wrong; of next 10, 7 wrong; of next 10, 6 wrong; of next 10, 7; of the -next, 9; of the next, 9; of the next, 4; of the next, none; of the next, -3; of the next, 2, and then 70 trials without an error. - -[Illustration: FIG. 29.] - -I will describe some of the experiments in detail and then discuss the -graphic presentation of them all. - - -EXPERIMENTS WITH NO. 1 - -Having developed in No. 1 the habit of coming down to the bottom of his -cage to get a bit of food when he saw me reach out and take such a bit -from my desk, I tested his ability to discriminate by beginning to use -now one hand, now the other, feeding him only when I used the left. -I also used different sets of words, namely, ‘I will give some food’ -and ‘They shall not have any.’ It will be seen later that he probably -reacted only to the difference of the hands. The experiment is similar -to that described on pages 129 and 130 of Chapter II. At the beginning, -it should be remembered, No. 1 would come down whichever hand was used, -no matter what was said, except in the occasional cases where he was so -occupied with some other pursuit as to be evidently inattentive. He did -come to associate the act of going down with the one signal and the act -of staying still or continuing his ordinary movements with the other -signal. His progress in learning to do so is best seen in the curves of -his errors. To the ‘yes’ signal he responded correctly, except for the -occasional lapses which I just mentioned, from the start and throughout. -With the ‘no’ signal his errors were as shown in Fig. 30, _a_. The break -in the curve at 110 and 120 is probably not significant of an actual -retrograde as the trials concerned followed an eight days’ cessation of -the experiments. - -I next tried No. 1 with an apparatus exposing sometimes a card with a -diamond-shaped piece of buff-colored paper on it and sometimes a card -with a similar black piece. The black piece was three fourths of an -inch farther behind the opening than the other. The light color was the -‘yes’ signal. The error curves for both signals are given, as No. 1 at -the beginning of the experiment did not go down always (Fig. 30, _b_ and -_b₁_). - -I next tried No. 1 with the same apparatus but exposing cards with YES -and N in place of the buff and black diamonds. The record of the errors -is given in Fig. 30, _c_ and _c₁_. At the start he came down halfway very -often. This I arbitrarily scored as an error no matter which signal it -was in response to. It should not be supposed that these curves represent -two totally new associations. It seems likely that the monkey reacted to -the _position_ of the N card in the apparatus (the same as that of the -black diamond card) rather than to the shape of the letters. On putting -the black diamond in front he was much confused. - -I next gave No. 1 the chance to form the habits of coming down when I -rapped my pencil against the table twice and of staying where he was when -I rapped with it once. He had 90 trials of each signal but failed to give -evidence of any different associations in the two cases. - -Experiments of this sort were discontinued in the summer. In October I -tried No. 1 with the right and left hand experiment, he being in a new -room and cage, and I being seated in a different situation. He came down -at both signals and failed to make any ascertainable progress with the no -signal in 80 trials. (October 20-24.) - -[Illustration: FIG. 30.] - -I then tried him with the black and buff diamonds, the black being in -front (October 25-29). The reaction to the ‘yes’ signal was perfect from -the start. The progress with the ‘no’ signal is shown in Fig. 30, _d_. - -I then tried him with an apparatus externally of different size, shape -and color from that so far used, showing as the ‘yes’ signal a brown -card and as the ‘no’ signal a white and gold card one half inch farther -back in the apparatus. The ‘yes’ signal was practically perfect from the -start. His progress with the ‘no’ signal is shown in Fig. 30, _e_. - -I then tried a still different arrangement for exposure, to which, -however, he did not give uniform attention. - -I then tried cards 1 and 101, 101 being in front and 1 in back. 1 was -the ‘yes’ signal. ‘Yes’ responses were perfect from the start. For ‘no’ -responses see Fig. 30, _f_. I then put the ‘yes’ signal in front and the -‘no’ signal behind. ‘Yes’ responses perfect; for ‘no’ responses see Fig. -30, _f_, _a_. - -From now on I arranged the exposures in such a way that there was no -difference between the ‘yes’ and ‘no’ signals in distance or surroundings. - -The following list shows the dates, signals used, and the figures on -page 199 presenting the results. Where there is only one figure drawn, -it refers to progress with the ‘no’ signal, the ‘yes’ signal being -practically perfect from the start. - - -TABLE 10 - - ==================+==============+=============+======== - | ‘YES’ SIGNAL | ‘NO’ SIGNAL | FIGURE - ------------------+--------------+-------------+-------- - Nov. 13-15, 1900. | 2 | 102 | _g g₁_ - Nov. 14-16, 1900. | 3 | 103 | _i i₁_ - Nov. 16-19, 1900. | 4 | 104 | _h_ - Nov. 19, 1900. | 5 | 105 | _j_ - Nov. 20, 1900. | 6 | 106 | _k_ - Nov. 21, 1900. | 7 | 107 | _l_ - Nov. 23(?), 1900. | 8 | 108 | _m_ - Nov. 27-29, 1900. | 9 | 109 | _n_ - Nov. 30, 1900. | 10 | 110 | _o_ - ==================+==============+=============+======== - -Fig. 29 gives facsimiles of the different signals reduced to one sixth -their actual size. The drawing of 101 is not accurate, the outer ring -being too thick. - - -EXPERIMENTS WITH NO. 2 - -[Illustration: FIG. 31.] - -I first secured the partial formation of the habit of coming down when -I took a bit of food in my hand. I then used the apparatus for exposing -cards, YES in front being the ‘yes’ signal and a circle at the back being -the ‘no’ signal. I gave No. 2 25 trials with the ‘yes’ signal and then -began a regular experiment similar to those described. After about 90 -trials (November 9-12, 1900) there was no progress toward differentiation -of response, and it was evident from No. 2’s behavior that he was -reacting solely to the movements of my hand. So I abandoned the exposing -apparatus and used (November 11-13, 1900) as the ‘yes’ signal the act of -taking the food with my left hand from a pile on the front of the box and -for the ‘no’ signal the act of taking food with my right hand from a pile -4 inches behind that just mentioned. No. 2 did come to differentiate -these two signals. The record of his progress is given in Fig. 31 by _A_ -and _A₁_. - -I then made a second attempt with the exposing apparatus, using cards 2 -and 102 (November 6, 14-21). No. 2 did react to my movements in pulling -the string but in over 100 trials made no progress in the direction of -a differential reaction to the ‘no’ signal. I then tried feeding him at -each signal, feeding him at the bottom of the cage as usual when I gave -the ‘yes’ signal and at the top when I gave the ‘no’ signal. After a -hundred trials with the ‘no’ signal there was no progress. - -I then abandoned again the exposing apparatus and used as signals the -ordinary act of taking food with my left hand (yes) and the act of moving -my left arm from my right side round diagonally (swinging it on my elbow -as a center) and holding the hand, after taking the food, _palm up_ (no) -(November 26, 27, 1900). No. 2 did come to differentiate these signals. -His progress is given in the diagram in Fig. 31 entitled ‘Palm up’ (_B_). - -I next used (November 27, 1900) as the ‘yes’ signal the same act as -before and for the ‘no’ signal the act of holding the food just in front -of the box about four inches below the edge. No. 2’s progress is shown in -Fig. 31 in the diagram entitled ‘low front’ (_C_ and _C₁_). - -I next used (November 27-30) the same movement for both ‘yes’ and ‘no’ -signals save that as the ‘yes’ signal I took the food from a brown -pasteboard box 3 by 3 by 0.5, and as the ‘no’ signal I took it from a -white crockery cover two inches in diameter and three eighths of an -inch high which was beside the box but three inches nearer me. No. 2’s -progress is shown in Fig. 31 in the diagram entitled ‘Box near’ (_D_). - -I next used for the ‘yes’ signal the familiar act and for the ‘no’ -signal the act of holding the food six inches above the box instead of -a quarter or a half an inch. The progress is shown in Fig. 31, _E_ and -_E₁_. I then tried taking the food from a saucer off the front of the -box for the ‘yes’ signal and from a small box at the back for the ‘no’ -signal. ‘Yes’ was perfect from the start (10 trials given). ‘No’ was -right once, then wrong once, then right for the remaining eight. - - -EXPERIMENTS WITH NO. 3 - -No. 3 was kept in a cage not half so big as those of 1 and 2. Perhaps -because of the hindrance this fact offered to forming the habit of -reacting in some definite way to ‘yes’ signals, perhaps because of -the fact that I did not try hand movements as signals, there was no -successful discrimination by No. 3 of the yellow from the black diamond -or of a card with YES from a card with a circle on it. I tried climbing -up to a particular spot as the response to the ‘yes’ signal and staying -still as the response to the ‘no’ signal. I also tried instead of the -latter a different act, in which case the animal was fed after both -signals but in different places. In the latter case No. 3 made some -progress, but for practical reasons I postponed experiments with him. -Circumstances have made it necessary to postpone such experiments -indefinitely. - - -PERMANENCE OF THE ABILITY TO DISCRIMINATE - -No. 1 and No. 2 were tried again after intervals of 33 to 48 days. The -results of these trials are shown in Fig. 32. Here every millimeter -along the base line represents _one_ trial with the ‘no’ signal (the -‘yes’ signals were practically perfect), and failure is represented by a -column 10 mm. high while success is represented by the absence of any -column. Thus the first record reads, “No. 1 with signal 104 after 40 -days made 5 failures, then 2 successes, then 1 failure, then 1 success, -then 3 failures, then 1 success, then 1 failure, then 3 successes, then -1 failure, then 10 successes.” The third record (106; 40 days) reads, -“perfect success in ten trials.” - -[Illustration: FIG. 32.] - - -DISCUSSION OF RESULTS - -The results of all these discrimination experiments emphasize the -rapidity of formation of associations amongst the monkeys, which appeared -in their behavior toward the mechanisms. The suddenness of the change in -many cases is immediately suggestive of human performances. If all the -records were like c, f, h, i, j, k, l, m, B, E, and memory trials 103, -A, B, and C, one would have to credit the animals with either marvelous -rapidity in forming associations of the purely animal sort or concede -that from all the objective evidence at hand they were shown to learn as -human beings would. One would have to suppose that they had clear ideas -of the signals and clean-cut associations with those ideas. The other -records check such a conclusion. - -In studying the figures we should remember that occasional mistakes, say -1 in 10 trials, are probably not significant of incomplete learning but -of inattention or of precipitate action before the shutter had fairly -exposed the card. We must not expect that a monkey who totally fails to -discriminate will _always_ respond wrongly to the ‘no’ signal, or that -a monkey who has come to discriminate perfectly will _always_ respond -rightly. A sudden drop from an average high level of error to an average -low level will signify sudden learning. Where the failure was on the -first trial of a series a few hours or a day removed from the last -series, I have generally represented the fact not by a column 1 mm. high -and 1 mm. broad, but by a single 10 mm. perpendicular. See i and A. Such -cases represent probably the failure of the animal to keep his learning -permanent rather than any general inability to discriminate. - -K was to some extent a memory trial of d (after over half a year). - -The experiment with 10 and 110 is noteworthy. Although, as can be seen -from the figures, the difference is obvious to one looking at the white -part of the figure, it is not so to one looking at the black part. No. -1 failed to improve appreciably in fifty trials, probably because his -previous experience had gotten him into the habit of attending to the -black lines. - -Before arguing from the suddenness of the change from failure to success -we have to consider one possibility that I have not mentioned, and in -fact for the sake of clearness in presentation have rather concealed. It -is that the sudden change in the records, which report only whether the -animal did or did not go down, may represent a more gradual change in -the animal’s mind, a gradual weakening of the impulse to go down which -makes him feel less and less inclined to go down, though still doing so, -until this weakening reaches a sort of saturation point and stops the -action. There were in their behavior some phenomena which might witness -to such a process, but their interpretation is so dependent on the -subjective attitude and prepossessions of the observer that I prefer not -to draw any conclusions from them. On the other hand, records c, g, n, A -and D seem to show that gradual changes can be paralleled by changes in -the percentage of failures. - -In the statement of conclusions I shall represent what would be the -effect on our theory of the matter in both cases, (1) taking the records -to be fairly perfect parallels of the process, and (2) taking them to be -the records of the summation points of a process not shown with surety in -any measurable objective facts. But I shall leave to future workers the -task of determining which case is the true one. - -If we judge by the objective records themselves, we may still choose -between two views. (1) We may say that the monkeys did come to have -ideas of the acts of going down to the bottom of the cage and of staying -still, and that their learning represented the association of the -sense-impressions of the two signals, one with each of these ideas, or -possibly their association with two other ideas (of being fed and of -not being fed), and through them with the acts. Or (2) we may say that -the monkeys had no such ideas, but merely by the common animal sort of -association came to react in the profitable way to each signal. - -If we take the first view, we must explain the failure of the animals -to change suddenly in some of the experiments, must explain why, for -instance, No. 1 in g should, after he had responded correctly to the -‘no’ signal for 27 trials out of 30, fail in one trial out of four for -a hundred or more trials. If the 27 successes were due to ideas, why -was there regression? If the animal came to respond by staying still on -seeing the K (card 104), because that sight was associated with the idea -of no food or the idea of staying still, why did he, in his memory trial, -act sometimes rightly, sometimes wrongly, for eleven trials after his -acting rightly twice. If he stayed still because the idea was aroused, -why did he not stay still as soon as he had a few trials to remind him of -the idea? It is easy, one may say, to see why, with a capacity to select -movements and associate them with sense-presentations very quickly, in -cases where habit provides only two movements for selection and where the -sense-presentation is very clear and simple, an animal should practically -at once be confirmed in the one act on an occasion when he does it with -the sense-impression in the focus of attention. It is easy, therefore, to -explain the sudden change in i, l, m, B, C and E. But our critic may add, -“It is very hard to suppose that an animal that learned by connecting -the sight of a card with the idea ‘stay still’ or the idea ‘no food,’ -should be so long in making the connection as was the case in some of -these experiments, should take 10, 20 or 40 trials to change from a high -percentage of wrong to a high percentage of right reactions.” - -If we take the second view, we have to face the fact that many of the -records are nothing like the single one we have for comparison, that of -the kitten shown in Fig. 30, and that the appeal to a capacity to form -animal associations very quickly seems like a far-fetched refuge from the -other view rather than a natural interpretation. If we take the records -to be summation points in a more gradual process, this difficulty is -relieved. - -If further investigation upheld the first view, we should still not have -a demonstration that the monkeys habitually did learn by getting percepts -and images associated with sense-impressions, by having free ideas of the -acts they performed; we should only have proved that they could under -certain circumstances. - -The circumstances in these experiments on discrimination were such as to -form a most favorable case. The act of going down had been performed in -all sorts of different connections and was likely to gain representation -in ideational life; the experience ‘bit of banana’ had again been -attended to as a part of very many different associations and so would be -likely to develop into a definite idea. - -These results then do not settle the choice between three theories: (1 -_a_) that they were due to a general capacity for having ideas, (1 _b_) -that they were due to ideas acquired by specially favoring circumstances, -(2) that they were due to the common form of association, the association -of an impulse to an act with a sense-impression rather roughly felt. - -It would be of the utmost interest to duplicate these experiments with -dogs, cats and other mammals and compare the records. Moreover, since -we shall find (1 _a_) barred out by other experiments, it will be of -great interest to test the monkeys with some other type of act than -discrimination to see if, by giving the animal experience of the act and -result involved in many different connections, we can get a rate of speed -in the formation of a new association comparable to the rates in some of -these cases. - -Of course here, as in our previous section, the differences in the -sense-powers of the monkeys from those of the kitten which I have tested -with a similar experiment may have caused the difference in behavior. -Focalized vision lends itself to delicate associations. Perhaps if one -used the sense of smell, or if the dogs and cats could, preserving their -same mental faculties in general, add the capacity for focalized vision, -they would do as well as the monkeys. - - -EXPERIMENTS ON THE INFLUENCE OF TUITION - -The general aim of these experiments was to ascertain whether the -monkeys’ actions were at all determined by the presence of free ideas -and if so, to what extent. The question is, “Are the associations which -experience leads them to form, associations between (1) the idea of an -object and (2) the idea of an act or result and (3) the impulses and act -itself, or are they merely associations between the sense-impression -of the object and the impulse and act?” Can a monkey learn and does he -commonly learn to do things, not by the mere selection of the act from -amongst the acts done by him, but by getting some idea and then himself -providing the act because it is associated in his mind with that idea. If -a monkey feels an impulse to get into a box, sees his arm push a bar and -sees a door fall open immediately thereafter and goes into the box enough -times, he has every chance to form the association between the impulse to -get into the box and the idea ‘arm push bar,’ provided he can have such -an idea. If his general behavior is due to having ideas connected with -and so causing his acts, he has had chance enough to form the association -between the idea ‘push at’ and the act of pushing. If then a monkey forms -an association leading to an act by being put through the act, we may -expect that he has free ideas. And if he has free ideas in general in -connection with his actions, we may expect him to so form associations. -So also if a monkey shows a general capability to learn from seeing -another monkey or a human being do a thing. A few isolated cases of -imitation, however, might witness not to any general mental quality, but -only to certain instincts or habits differing from others only in that -the situation calling forth the act was the same act performed by another. - -If the monkeys do not learn in these ways, we must, until other evidence -appears, suppose them to be in general destitute of a life of free ideas, -must regard their somewhat ambiguous behavior in learning by their -own unaided efforts as of the same type as that of the dogs and cats, -differing only in the respects mentioned on pages 190 and 191. - -The general method of experimentation was to give monkeys who had failed -of their own efforts to operate some simple mechanism, a chance to see -me do it or see another monkey do it or to see and feel themselves do -it, and then note any change in their behavior. The chief question is -whether they succeed after such tuition when they have failed before -it, but the presence of ideas would also be indicated if they attacked, -though without success, the vital point in the mechanism when they had -not done so before. On the other hand, mere success would not prove that -the tuition had influenced them, for if they made a different movement -or attacked a different spot, we could not attribute their behavior to -getting ideas of the necessary act. - -The results of the experiments as a whole are on their face value a -trifle ambiguous, but they surely show that the monkeys in question had -no considerable stock of ideas of the objects they dealt with or of the -movements they made and were not in general capable of acquiring, from -seeing me or one of their comrades attack a certain part of a mechanism -and make a certain movement, any ideas that were at all efficacious in -guiding their conduct. They do not acquire or use ideas in anything that -approaches the way human adults do. Whether the monkeys may not have some -few ideas corresponding to habitual classes of objects and acts is a -different question. Such may be present and function as the excitants of -acts. - -It is likely that this question could have been definitely solved if it -had been possible for me to work with a larger number of animals. With -enough subjects one could use the method mentioned on page 105 of Chapter -II, of giving the animals tuition in acts which they would eventually do -themselves without it, and then leaving them to their efforts, noting any -differences in the way they learned from that in which other subjects who -had no tuition learned the same acts. The chief of such differences to -note would be differences in the time of their first trial, in the slope -of the time-curve and in the number of useless acts. - -It would also be possible to extend experiments of the type of the -(on chair) experiment, where a subject is given first a certain time -(calculated by the experimenter to be somewhat less than would be needed -for the animal to hit upon the act) and if he does fail is then given -certain tuition and then a second trial. The influence of the tuition is -estimated by the presence or absence of cases where after tuition the act -is done within the time. - -There is nothing necessarily insoluble in the problem. Given ten or -twenty monkeys that can be handled without any difficulty and it could be -settled in a month. - -With this general preface we may turn to the more special questions -connected with the experiments on imitation of human acts and of the acts -of other monkeys and on the formation of associations apart from the -selection of impulses. - - -IMITATION OF HUMAN BEINGS - -It has been a common opinion that monkeys learned to do things from -seeing them done by human beings. We find anecdotes to that effect in -fairly reputable authors. - -Of course, such anecdotes might be true and still not prove that the -animals learned to do things because they saw them done. The animal -may have been taught in other ways to respond to the particular sights -in question by the particular acts. Or it may have been in each case a -coincidence. - -If a monkey did actually form an association between a given situation -and act by seeing some one respond to that situation by that act, it -would be evidence of considerable importance concerning his general -mental status, for it would go to show that he could and often did form -associations between sense-impressions and ideas and between ideas and -acts. Seeing some one turn a key in a lock might thus give him the -idea of turning or moving the key, and this idea might arouse the act. -However, the mere fact that a monkey does something which you have just -done in his presence need not demonstrate or even render a bit more -probable such a general mental condition. For he perhaps would have acted -in just the same manner if you had offered him no model. If you put -two toothpicks on a dish, take one and put it in your mouth, a monkey -will do the same, not because he profits by your example, but because -he instinctively puts nearly all small objects in his mouth. Because of -their general activity, their instinctive impulses to grab, drop, bite, -rub, carry, move about, turn over, etc., any novel object within their -reach, their constant movement and assumption of all sorts of postures, -the monkeys perform many acts like our own and simulate imitation to a -far greater extent than other mammals. - -Even if a monkey which has failed of itself to do a certain thing does it -after you have shown him the act, there need be no reason to suppose that -he is learning by imitation, forming an association between the sight of -the object and the act towards it through an idea gained from watching -you. You may have caused his act simply by attracting his attention to -the object. Perhaps if you had pointed at it or held it passively in your -hand, you would have brought to pass just the same action on his part. -There are several cases among my records where an act which an animal -failed totally to do of himself was done after I had so attracted his -attention to the object concerned. - -Throughout all the time that I had my monkeys under observation I never -noticed in their general behavior any act which seemed due to genuine -imitation of me or the other persons about. I also gave them special -opportunities to show such by means of a number of experiments of the -following type: where an animal failed by himself to get into some box or -operate some mechanism, I would operate it in his presence a number of -times and then give him a chance to profit by the tuition. His failure -might be due to (1) the absence of instinctive impulses to make the -movement in that situation, (2) to lack of precision in the movement, (3) -to lack of force, or (4) to failure to notice and attack some special -part of the mechanism. An instance of (1) was the failure to push away -from them a bar which held a door; an instance of (2) was the failure to -pull a wire loop off a nail; an instance of (2) or (3) was the failure to -pull up a bolt; an instance of (4) was the failure to pull up an inside -bar. Failures due to (3) occur rarely in the case of such mechanisms as -were used in my investigations. - -The general method of experiment was to make sure that the animal would -not of itself perform a certain act in a certain situation, then to make -sure that his failure could not be remedied by attracting his attention -to the object, then to perform the act for him a number of times, letting -him get each time the food which resulted, and finally to see whether, -having failed before the tuition, he would succeed after it. This sounds -very simple, but such experiments are hard to carry out satisfactorily. -If you try the animal enough times by himself to make quite sure that -he will not of himself hit upon the act, you are likely to form in him -the habit of meeting the particular situation in question with total -disregard. His efforts having failed so often may be so inhibited that -you could hardly expect any tuition to give them new life. The matter is -worse if you add further enough trials to assure you that your attracting -his attention to it has been unavailing. On the other hand, if you take -failure in five or ten minutes to mean inability, and from subsequent -success after imitation argue that imitation was efficient, you have to -face the numerous cases where animals which have failed in ten minutes -have succeeded in later unaided trials. With dogs and cats this does -not much matter, because they are steady performers, and their conduct -in one short trial tells you what to expect with some probability. But -the monkeys are much more variable and are so frequently distracted that -one feels much less confidence in his predictions. Moreover, you cannot -be at all sure of having attracted a monkey’s attention to an object -unless he does touch it. Suppose, for example, a monkey has failed to -even touch a bar though you have put a bit of food on it repeatedly. It -is quite possible that he may look at and take the food and not notice -the bar, and the fact that after such tuition he still fails to push or -pull the bar may mean simply that it has not caught his notice. I have, -therefore, preferred in most cases to give the animals only a brief -period of trial to test their ability by their own unaided efforts and -to omit the attempts to test the efficacy of attracting their attention -to the vital point in the mechanism. This makes the results appear less -elegant and definitive but really increases their value for purposes of -interpretation. - -The thoughtful reader will not expect from my experiments any perfectly -rigorous demonstration of either the presence or the absence of imitation -of human acts as a means of learning. The general trend of the evidence, -it seems to me, is decidedly towards justifying the hypothesis that the -monkeys did not learn acts from seeing me do them. - -I will first describe a sample experiment and then present a summary of -all those made. - -On January 12th I put box Epsilon (push down) in No. 3’s cage, the door -of the box being open. I put a bit of food in the box. No. 3 reached -in and took it. This was repeated three times. I then put in a bit of -food and closed the door. No. 3 pulled and bit the box, turned it over, -fingered and bit at the hole where the lever was, but did not succeed -in getting the door open. After ten minutes I took the box out. Later I -took No. 3 out and let him sit on my knees (I sitting on the floor with -the box in front of us). I would then put my hand out toward the box and -when he was looking at it would insert my finger and depress the lever -with as evident a movement as I could. The door, of course, opened, and -No. 3 put his arm in and took the bit of food. I then put in another, -closed the door and depressed the lever as before. No. 3 watched my hand -pretty constantly, as all his experiences with me had made such watching -profitable. After ten such trials he was put back in the cage and the -box put in with a large piece of food in it and its door closed. No. 3 -failed in five minutes and the box was taken out. He was shown fifteen -times more and then left to try himself. I tried him for a couple of -minutes under just the same circumstances as existed during the tuition, -_i.e._ he on the floor by me, the box in front. In this trial and in a -five-minute trial inside his cage he failed to open the door or to differ -in any essential respect from his behavior before tuition. - -No. 1 saw me do 9 different acts and No. 3, 7, which they had failed -of themselves to do.[30] After from 1 to 40 chances to imitate me they -still failed to operate at all 11 of these mechanisms. In the case of -3 out of 5 that were worked the act was not the same as that taught. -No. 1, who saw me pull a nail out by taking the end of it and pulling -the nail away from the box, himself put his hand round the nail and -wriggled it out by pulling his hand back and forth. No. 3, who saw me -pull a bolt up with my fingers, succeeded by jerking and yanking the door -until he shook the bolt up. He saw me pull a hook out of an eye, but he -succeeded by pulling at a bar to which it was attached. In the case of -one of the two remaining acts (No. 3 with _nail chute_) the act was done -once and never again, though ample opportunity was given and tuition -continued. It could, therefore, hardly have been due to an idea instilled -by the tuition. The remaining case, No. 1, with loop, must, I think, -be attributed to accident, especially since No. 3 failed to profit by -precisely the same sort of tuition with precisely the same act. - -Nor is there any evidence to show that although tuition failed to cause -successes where unaided effort failed, it yet caused attempts which would -not otherwise have occurred. Out of fifteen cases where such might have -appeared, there were only three where it is possible to claim that they -did. No one of these three is a sure case. With RR (wood plug) No. 1 did -seem to pull the plug more definitely after seeing me than before. With -QQ (c) (nail chute) and MM (bolt at top) he may possibly have done so. - -In 5 cases I tried the influence of seeing me make the movement on -animals who had done the act of themselves, the aim being to see whether -there would be a marked shortening of the time, a change in their way of -operating the mechanism or an attempt at such change. I will give the -essential facts from the general table on pages 226-229. - -(_a_) No. 1 had succeeded in pulling in the box by the upper string in -OOO (upper string box) in 2.20 and then failed in 3.00. I showed him 4 -times. He failed in 10. I showed him 4 more times. He failed in 10. I -showed him 4 more times. He succeeded in .20. No change in manner of act -or objects attacked, though my manner was different from his. - -(_b_) No. 1 had succeeded in QQ (a) (chute bar) in 8.00. I showed him 20 -times. He failed in 10. I showed him 10 more times. He succeeded in 2.00. -I showed him 10 more times. He succeeded in 50 seconds. No change in his -manner of performance or in the object attacked, though my manner was -different from his. - -(_c_) No. 1 had succeeded in 3.00, .25, .07, .25, .20, .06 and .09 with -QQ (b) (chute bar double) and then failed in 5.00. I showed him 10 times. -He then failed in 5 twice, succeeded in 3.00, and failed in 5 again. No -change in manner of performance or in the object attacked, though my -manner was different from his. - -(_d_) No. 3 had the following record in box Delta:— - - 2.00 (pushed with head) - 3.20 (pushed with head) - 30 F - 10 F - 10 F - 2.10 (pulled wire and door). - -I showed him 20 times by pushing the bar to the right with my finger. He -succeeded in 8.00 and 8.00 by pulling the wire and the door. No change in -object attacked. - -(_e_) No. 2 had failed twice in 5 with chute QQ (ff) (chute string wire) -and succeeded once in 2.00 by a strong pull on the wire itself, not the -loop. I showed him 5 times, pulling the loop off the nail. He then failed -in 5. There was no change in the objects attacked. - -These records show no signs of any influence of the tuition that are -not more probably signs of something else. We cannot attribute the -rapid decrease in time taken in (_b_) to the tuition until we know the -time-curve for the same process without tuition. - -The systematic experiments designed to detect the presence of ability to -learn from human beings are thus practically unanimous against it. So, -too, was the general behavior of the monkeys, though I do not consider -the failure of the animals to imitate common human acts as of much -importance save as a rebuke to the story-tellers and casual observers. -The following facts are samples: The door of No. 1’s cage was closed by -an iron hoop with a slit in it through which a staple passed, the door -being held by a stick of wood thrust through the staple. No. 1 saw me -open the door of his and other cages by taking out sticks hundreds of -times, but though he escaped from his cage a dozen times in other ways, -he never took the stick out and to my knowledge never tried to. I myself -and visitors smoked a good deal in the monkeys’ presence, but a cigar or -cigarette given to them was always treated like anything else. - - -IMITATION OF OTHER MONKEYS - -It would theoretically seem far more likely that the monkeys should -learn from watching each other than from watching human beings, and -experimental determinations of such ability are more important than those -described in the last section as contributions both to genetic psychology -and to natural history. I regret that the work I have been able to do in -the study of this phase of the mental life of the monkeys has been very -limited and in many ways unsatisfactory. - -We should expect to find the tendency to imitation more obvious in the -case of young and parents than elsewhere. I have had no chance to observe -such cases. We should expect closely associated animals, such as members -of a common troop or animals on friendly terms, to manifest it more -than others. Unfortunately, two of my monkeys, by the time I was ready -to make definite experiments, were on terms of war. The other had then -become so shy that I could not confidently infer inability to do a thing -from actual failure to do it. He showed no evidence of learning from his -mates. I have, therefore, little evidence of a quantitative objective -nature to present and shall have in the end to ask the reader to take -some opinions without verifiable proofs. - -My reliable experiments, five in number, were of the following nature. A -monkey who had failed of himself (and often also after a chance to learn -from me or from being put through the act) would be put where he could -see another do the act and get a reward (food) for it. He would then be -given a chance to do it himself, and note would be taken of his success -or failure, and of whether his act was the same as that of his model in -case he succeeded, and of whether he tried that act more than before the -tuition in case he tried it and failed. The results are given in Table 11. - -In the fourth experiment No. 1 showed further that the tuition did not -cause his successes in that after some successes further tuition did not -improve him. - -There is clearly no evidence here of any imitation of No. 1 by No. 3. -There was also apparently nothing like purposive watching on the part -of No. 3. He seemed often to see No. 1 open the box or work the chute -mechanism, but without special interest. - -This lack of any special curiosity about the doings of their own species -characterized the general behavior of all three of my monkeys and in -itself lessens the probability that they learn much from one another. Nor -did there appear, in the course of the three months and more the animals -were together, any signs of imitation. There were indeed certain notable -instances of the lack of it in circumstances which one would suppose -would be favorable cases for it. - -For instance: No. 2 was very timid. No. 1 was perfectly tame from the -first day No. 2 was with me, and No. 3 became tame shortly after. No. -2 saw Nos. 1 and 3 come to me, be played with, fed and put through -experiments, yet he never did the same nor did he abate a jot or tittle -from his timidity save in so far as I sedulously rewarded any chance -advances of his. Conversely No. 1 and No. 3 seemed uninfluenced by the -fear and shyness of No. 2. No. 2’s cage was between No. 1’s and No. 3’s, -and they were for three weeks incessantly making hostile demonstrations -toward each other, jumping, chattering, scowling, etc. No. 2 never did -anything of the sort. Again, seeing No. 3 eat meat did not lead No. 1 to -take it; nor did seeing No. 1 retreat in fright from a bit of absorbent -cotton lead No. 3 to avoid it. - - -TABLE 11 - - Table headings: - Column A: SUBJECT, DATE, ACT - Column B: TIME TRIED ALONE, WITH RESULT - Column C: NO. OF TIMES IMITATEE DID - Column D: RESULT AFTER CHANCE FOR IMITATION - Column E: SIMILARITY OR DISSIMILARITY OF ACT - Column F: SIMILAR ACT ATTEMPTED, THOUGH UNSUCCESSFULLY IN CASES WHERE - IT HAD NOT BEEN BEFORE TRAINING - Column G: GENERAL JUDGMENT AS TO INFLUENCE OF TRAINING - - ======================+========+====+======+=============+=====+======= - A | B | C | D | E | F | G - ----------------------+--------+----+------+-------------+-----+------- - No. 3. Dec. 17, 1900. | 50 F | 43 | 55 F | | No. | None. - VV (wire loop) | | | | | | - No. 3. Jan. 15, 1901. | 91 F | 75 | 35 F | | No. | None. - QQ (c) (nail chute) | 1.30 | | | | | - No. 3. Jan. 21, 1901. | 63 F | 43 | 5 F | Dissimilar. | No. | None. - Gamma (wind) | | | 9.00 | | | - | | | 6.00 | | | - No. 3. Jan. 21, 1901. | 20 F | 30 | 1.30 | Dissimilar. | No. | None. - QQ (ff) (string | 2.00 | | .40 | | | - chute with wire) | | | .35 | | | - | | | 5 F | | | - No. 3. Jan. 23, 1901. | 1.15 F | 40 | 10 F | | No. | None. - QQ (chute) | | | | | | - ======================+========+====+======+=============+=====+======= - -Nothing in my experience with these animals, then, favors the hypothesis -that they have any general ability to learn to do things from seeing -others do them. The question is still an open one, however, and a much -more extensive study of it should be made, especially of the possible -influence of imitation in the case of acts already familiar either as -wholes or in their elements. - - -LEARNING APART FROM MOTOR IMPULSES - -The reader of my monograph, ‘Animal Intelligence,’ will recall that the -experiments there reported seemed to show that the chicks, cats and -dogs had only slight and sporadic, if any, ability to form associations -except such as contained some actual motor impulse. They failed to form -such associations between the sense-impressions and ideas of movements -as would lead them to make the movements without having themselves -previously in those situations given the motor impulses to the movements. -They could not, for instance, learn to do a thing from having been put -through it by me. - -The monkeys Nos. 1 and 3 were tested in a similar way with a number of -different acts. The general conclusion from the experiments, the details -of which will be given presently, is that the monkeys are not proved to -have the power of forming associations of ideas to any greater extent -than the other mammals, that they do not demonstrably learn to do things -from seeing or feeling themselves make the movement. An adult human -being whose hand was taken and made to push in a bar or pull back a bolt -would thereby learn to do it for himself. Cats and dogs would not, and -the monkeys are not proved to do so. On the other hand, it is impossible -for me to say, as of the dogs and cats, that the monkeys are proved not -to do so. In a few cases the animals did perform acts after having been -put through them which they had failed to perform when left to their own -trial and success method. In the majority of cases they did not. And -in some of these latter cases failure seemed so improbable in case the -animal really had the power of getting an idea of the act and proceeding -from idea to execution, that one is inevitably led to some explanation -for the few successes other than the presence of ‘ideas.’ - -The general manner of making these experiments was like that in the case -of the cats and dogs, save that the monkey’s paw was used to open the -box from the outside instead of from the inside, and that the monkeys -were also put through the acts necessary to operate some of the chute -mechanisms. Tests parallel to that of comparing the behavior of kittens -who had themselves gone into boxes with those who were dropped in by me -were made in the following manner. I would carry a monkey from his cage -and put him in some conspicuous place (_e.g._ on the top of a chair) -and then give him a bit of food. This I would repeat a number of times. -Then I would turn him loose in the room to see whether he had acquired -an idea of being on the chair which would lead him to himself go to the -chair. I would, in order to tell whether his act, in case he did so, was -the result of random activities or was really due to his tuition, leave -him alone for 5 or 10 minutes before the tuition. If he got on the chair -afterwards when he had not before, or got on it much sooner, it would -tend to show that the idea of getting food on that chair was present and -effective. We may call these last the ‘on chair’ type of experiments. - -A sample experiment with a box is the following:— - -On January 4, 1901, box Delta (push back) was put in No. 1’s cage. He -failed in 5, though he was active in trying to get in for about 4 minutes -of the time and pulled and pushed the bar a great deal, though up and -down and out instead of back. In his aimless pushings and pullings he -nearly succeeded. He failed in 5 in a second trial also. I then opened -the door of the cage, sat down beside it, held out my hand, and when he -came to me took his right paw and with it (he being held in front of the -box) pushed the bar back (and pulled the door open in those cases when it -did not fall open of itself). He reached in and took the food and went -back to the top of his cage and ate it. (No. 1 generally did this, while -No. 3 generally stayed by me.) I then tried him alone; result 10 F; no -activity at all. On January 5th I put the box in; result 10 F. He was -fairly active. He pulled at the bar but mostly from a position on the top -of the box and with his left hand; no attempts like the one I had tried -to teach him. Being left alone he failed in 5. Being tried again with -the door of the cage open and me sitting as I had done while putting him -through the act, he succeeded in 7.00 by pushing the bar with his head -in the course of efforts to poke his head in at the door. I then put him -through the act 10 times and left him to himself. He failed in 5.00; no -activity. I then sat down by the cage as when teaching him. He failed in -5; little activity. Later in the day I put him through the act 10 times -and then left him to himself. He failed in 5; little activity. I sat -down as before. He failed in five; little activity. On January 6th I put -him through the act 10 times and then left him. He failed in 10. This -was repeated later in the day with the same result. Record:—By himself, -10 F. Put through 80 times. F 65 (a) [the (a) refers to a note of his -unrepeated chance success with his head]. No similar act unsuccessfully -attempted. Influence of tuition, none. - -With the chute mechanisms the record would be of the same nature. With -them I put the animal through generally by taking his paw, held out -through the wire netting of the cage, and making the movement with it. -In one experiment (No. 3 with QQ chute) the first 58 trials were made by -taking the monkey outside the cage and holding him instead of having him -put his paw through the netting for me to take. - -Many of the experiments were with mechanisms which had previously -been used in experiments concerning the ability to learn from seeing -me operate them. And the following Table (12) includes the results of -experiments of both sorts. The results of experiments of the ‘on chair’ -type are in Table 13. In cases where the same apparatus was used for both -purposes, the sort of training which was given first is that where an A -is placed. - -In the first four experiments with No. 1 there was some struggling and -agitation on his part while being held and put through the act. After -that there was none in his case except occasional playfulness, and there -was never any with No. 3 after the first third of the first experiment. -The monkeys soon formed the habit of keeping still, because it was only -when still that I put them through the act and that food resulted. After -you once get them so that they can be held and their arms taken without -their clinging to you, they quickly learn to adapt themselves to the -experiments. - -With No. 1, out of 8 cases where he had of himself failed (in five of the -cases he had also failed after being shown by me), he succeeded after -being put through (13, 21, 51, 10, 7, 80, and 10 times) in two cases (QQ -(chute) and RR (wood plug). The act was unlike the one taught him in the -former case. - - -TABLE 12 - - Table headings: - Column A: SUBJECT. DATE. ACT - Column B: TIMES TRIED ALONE, WITH RESULT - Column C: NUMBER OF TIMES ATTENTION ATTRACTED - Column D: RESULT - Column E: NUMBER OF TIMES SHOWN BY ME - Column F: RESULT IN TRIALS AFTER BEING SHOWN BY ME - Column G: NUMBER OF TIMES PUT THROUGH THE ACT - Column H: RESULT IN TRIALS AFTER BEING PUT THROUGH THE ACT - Column I: COMPARISON OF ACT USED WITH ACT TAUGHT - Column J: SIMILAR ACT ATTEMPTED THOUGH UNSUCCESSFULLY - Column K: ACT DONE ONCE OR MORE, BUT NOT REPEATED IN SPITE OF - REPEATED TUITION - - ========================+==========+====+========+========+========+ - A | B | C | D | E | F | - ------------------------+----------+----+--------+--------+--------+ - No. 1, Jan. 7, 1900, | 10 F | | | | | - PP (string across) | 10 F | | | | | - | | | | | | - No. 1, Jan. 17, 1900, | 15 F | | | 21 A |150 F | - MM (bolt at top) | | | | | 10 F | - | | | | | | - No. 1, Feb. 24, 1900, | 2.20 | | | 4} | 10 F | - OOO (upper string) | 3 F | | | 4} 12 | .20 | - | | | | 4} | | - | | | | 4 | .22 | - | | | | | | - No. 1, Mar. 24, 1900, | 120 F | | | 10 A | 60 F | - QQ (chute) | | | | | | - | | | | | | - No. 1, Apr. 5, 1900, | 10 F | 2 | 5 F | 1 A | 2 F | - RR (wood plug) | | | | 1 | 2 F | - | | | | 1 | 2 F | - | | | | 1 | 5 F | - | | | | | | - No. 1, Oct. 20, 1900, | 10 F | | | 4 | .22 | - VV (loop) | 10 F | | | | | - | 10 F | | | | | - | 10 F | | | | | - | | | | | | - No. 1, Nov. 19, 1900, | 10 F | | | 5 | 10 F | - Theta (new bolt) | | | | | | - | | | | | | - No. 1, Jan. 4, 1901, | 10 F | | | 15 | 10 F | - Delta (push back) | | | | | | - | | | | | | - No. 1, Jan. 6, 1901, | 8.00 | | | 40 | 10 F | - QQ (a) (single | | | | |2.00 | - wind chute) | | | | | .50 | - | | | | | | - No. 1, Jan. 7, 1901, | 5 F | | | | | - Zeta (side plug new) | | | | | | - | 1.10 | | | | | - | | | | | | - No. 1, Jan. 9, 1901, | 3.00 | | | 10 | 5 F | - QQ (b) (2½ | to .06 | | | | 5 F | - wind chute) | 5 F | | | |3.00 | - | | | | | 5 F | - | | | | | | - No. 1, Jan. 11, 1901, | 5 F | 5 | 5 F | 1[32] |2.20 | - QQ (c) (nail chute) | 5 F | | | | | - | | | | | | - No. 1, Jan. 12, 1901, | 5 F | | | 25 A | 10 F | - Epsilon (push down) | 10 F | | | | 10 F | - | | | | 15 | 10 F | - | | | | | | - No. 1, Jan. 16, 1901, | 5 F | 5 | 3.30 | | | - QQ (d) (pull chute) | 5 F | | .10 | | | - | | | | | | - No. 1, Jan. 17, 1901, | 5 F | 5 | 5 F | 15 A | 5 F | - QQ (f) (string chute) | | | | | 5 F | - | | | | | | - No. 1, Jan. 18, 1901, | 5 F | 3 | im. | | | - QQ (e) (hook chute) | | | | | | - | | | | | | - No. 3, Dec. 17, 1900, | 60 F | 3 | 60 F | 10 A | 5 F | - QQ (chute) | | | | 30 | 30 F | - | | | | | | - No. 3, Dec. 17, 1900, | 10 F | | | | | - VV (loop) | 20 F | | | | | - | | | | | | - No. 3, Jan. 4, 1901, | 10 F | | | 20 |8.00[34]| - Delta (push back) | 2.10 | | | |8.00[34]| - | (by | | | | | - | pulling | | | | | - | string) | | | | | - | | | | | | - No. 3, Jan. 4, 1901, | 10 F | | | 30 | 10 F | - Gamma (wind) | 10 F | | | | 10 F | - | | | | | | - No. 3, Jan. 8, 1901, | 10 F[36]| | | 25 | 6 F | - Theta (bolt at top) | | | | | | - | | | | | | - No. 3, Jan. 9, 1901, | 10 F | | | |3.00[37]| - QQ (a) (chute bar) | | | | | | - | | | | | | - | | | | | | - | | | | | | - No. 3, Jan. 9, 1901, | | | | | | - QQ (b) (2½ wind chute)| 10 F | | | 20 | 8 F | - | | | | | 8 F | - | | | | | | - No. 3, Jan. 11, 1901, | 5 F | 10 | 5 F | 25 A | 5 F | - QQ (c) (nail chute) | 5 F | |12 F[38]| | 5 F | - | | | | |1.30 | - | | | | | 5 F | - | | | | |10 F | - | | | | | | - No. 3, Jan. 15, 1901, | 10 F | | | 25 A | 5 F | - Epsilon (push down) | | | | | 5 F | - | | | | | | - | | | | | | - No. 3, Jan. 16, 1901, | | | | | | - QQ (e) (hook chute) | 5 F | 5 | 5 F | 5 A |2.00 | - | | | | |1.25 | - | | | | |1.20 | - | | | | | | - No. 3, Jan. 19, 1901, | 5 F | | 5 | 5 A | 5 F | - QQ (ff) (string chute | 5 F | | | | | - with wire) | 2.00[39] | | | | | - | | | | | | - | | | | | | - No. 3, Jan. 22, 1901, | 5 F | | | | | - WW (bar inside) |previously| | | | | - | some | | | | | - | 40.00 F | | | | | - ========================+==========+====+========+========+========+ - - ========================+======+========+===========+========+====== - A | G | H | I | J | K - ------------------------+------+--------+-----------+--------+------ - No. 1, Jan. 7, 1900, | 13 | 10 F | | No. | - PP (string across) | | | | | - | | | | | - No. 1, Jan. 17, 1900, | 21 | 10 F | | (?) | - MM (bolt at top) | | | | | - | | | | | - No. 1, Feb. 24, 1900, | | | Partly | | - OOO (upper string) | | | similar. | No. | - | | | | | - | | | | | - | | | | | - No. 1, Mar. 24, 1900, | 10 | 30.00 |Dissimilar.| No. | - QQ (chute) | | | | | - | | | | | - No. 1, Apr. 5, 1900, | 7 | 2.20 | Similar. | Yes(?) | - RR (wood plug) | 2 | 2.00 | | | - | | | | | - | | | | | - | | | | | - No. 1, Oct. 20, 1900, | | | Similar. | | - VV (loop) | | | | | - | | | | | - | | | | | - | | | | | - No. 1, Nov. 19, 1900, | 51 A | 132 F | | No. | - Theta (new bolt) | | | | | - | | | | | - No. 1, Jan. 4, 1901, | 80 A |65 F[31]| | No. | - Delta (push back) | | | | | - | | | | | - No. 1, Jan. 6, 1901, | | |Dissimilar.| | - QQ (a) (single | | | | | - wind chute) | | | | | - | | | | | - No. 1, Jan. 7, 1901, | | | | | - Zeta (side plug new) | 20 | im. | ? | | - | | im. | | | - | | | | | - No. 1, Jan. 9, 1901, | | |Dissimilar.| No. |Yes. - QQ (b) (2½ | | | | | - wind chute) | | | | | - | | | | | - | | | | | - No. 1, Jan. 11, 1901, | | |Dissimilar.| |Yes.[33] - QQ (c) (nail chute) | | | | | - | | | | | - No. 1, Jan. 12, 1901, | 10 | 5 F | | No. | - Epsilon (push down) | 10 | 10 F | | | - | | | | | - | | | | | - No. 1, Jan. 16, 1901, | | | | | - QQ (d) (pull chute) | | | | | - | | | | | - No. 1, Jan. 17, 1901, | 10 | 5 F | | | - QQ (f) (string chute) | | | | | - | | | | | - No. 1, Jan. 18, 1901, | | | | | - QQ (e) (hook chute) | | | | | - | | | | | - No. 3, Dec. 17, 1900, |113 | 90 F | | (?) | - QQ (chute) | | | | | - | | | | | - No. 3, Dec. 17, 1900, | 23 | 20 F | | No. | - VV (loop) | | | | | - | | | | | - No. 3, Jan. 4, 1901, | 5 A |2.00[35]|Dissimilar.| No. | - Delta (push back) | 5 | 3.20 | | | - | 15 | 30 F | | | - | 5 | 10 F | | | - | | | | | - | | | | | - No. 3, Jan. 4, 1901, | 20 A | 5 F | | No. | - Gamma (wind) | | 8 F | | | - | | | | | - No. 3, Jan. 8, 1901, | | |Dissimilar.| | - Theta (bolt at top) | | | | | - | | | | | - No. 3, Jan. 9, 1901, | 10 | | | No | - QQ (a) (chute bar) | 10 | .40 | ? |complete| - | 10 | 1.00 | | circle.| - | 10 | 1.00 | | | - | | | | | - No. 3, Jan. 9, 1901, | | | | | - QQ (b) (2½ wind chute)| | 5 F |Dissimilar.| |Yes. - | | | | | - | | | | | - No. 3, Jan. 11, 1901, | 45 | 38 F | | No. |Yes. - QQ (c) (nail chute) | | | | | - | 10 | 10 F | | | - | | | | | - | | | | | - | | | | | - No. 3, Jan. 15, 1901, | 20 | 11.00 | | No. |Yes. - Epsilon (push down) | | 30 F | ? | | - | 15 | 10 F | | | - | | | | | - No. 3, Jan. 16, 1901, | | | | | - QQ (e) (hook chute) | 10 | .10 |Dissimilar.| No. | - | | .10 | | | - | | | | | - | | | | | - No. 3, Jan. 19, 1901, | 7 | 5 F | | | - QQ (ff) (string chute | 8 | 5 F | | | - with wire) | 12 | 3.00 |Dissimilar.| No. | - | | 5 F | | | - | | | | | - No. 3, Jan. 22, 1901, | 10 | 5 F | | | - WW (bar inside) | |6.00[40]| | | - | | | | | - | |7.00[40]|Dissimilar.| No. | - ========================+======+========+===========+========+====== - -In only one case (bolt at top) out of eight was there possibly any -attempt at the act after he had been put through which had not been made -before. The ‘yes or?’ in the table with RR was a case occurring after the -imitation of me but before the putting No. 1 through. - -Out of 6 cases where he had himself failed, No. 3 succeeded (after being -put through 113, 23, 20, 10, 10, 20 and 10 times) in 3 cases (chute bar, -push down and bar inside). The act was dissimilar in all three cases, -bearing absolutely no resemblance in one case. There was no unsuccessful -attempt at the act taught him in any of the cases. With the chute he -did finger the bar after tuition where he had not done so before, but -it was probably an accidental result of his holding his hand out toward -it for me to take as he had formed the habit of doing. In the case of -box Epsilon (push down), with which he succeeded by pushing his hand in -above the lever (an act which though unlike that taught him might be by -some considered to be due to an idea gained from the tuition), he failed -entirely after further tuition (15 times). - -Like the dogs and cats, then, the monkeys seemed unable to learn to do -things from being put through them. We may now examine those which they -did do of themselves before tuition and ask whether they learned the more -rapidly thereby or modified their behavior in ways which might be due to -the tuition. There are too few cases and no chance for comparison on the -first point; on the second the records are unanimous in showing no change -in the method of operating the mechanisms due to the tuition. - -As in Table 9, figures followed by F mean that in that length of time -the animal failed. Figures without an F denote the time taken by the -animal to operate the mechanism. - -As a supplement to Table 12 I have made a summary of the cases where the -animals did succeed after tuition, that shows the nature of the act shown -them as compared with the act they made use of. - - -SUPPLEMENT TO TABLE 12 - - ==========+=====================+===================+==================== - APPARATUS | MODEL GIVEN OR ACT | ACT OF NO. 1 | ACT OF NO. 3 - | PUT THROUGH | | - ----------+---------------------+-------------------+-------------------- - OOO |To pull upper |Pulled both strings| - | string. | alternately, but | - | | upper enough | - | | more to succeed. | - | | | - QQ |To push bar in. |Inserted fingers | - | | between bar and | - | | its slot and | - | | pulled and | - | | pushed vaguely. | - | | | - RR |To pull plug out |Pulled and bit. | - | with right hand. | | - | | | - VV |To pull loop off nail|_Similar._ | - | with right hand. | | - | | | - QQ (a) |To pull bar around |Pulled back |Pulled back - | toward him. | and forth | and forth - | | indiscriminately.| indiscriminately. - | | | - QQ (b) |To pull bar around |Pulled back | - | toward him in | and forth | - | 2½ continuous | indiscriminately.| - | revolutions. | | - | | | - QQ (c) |To take nail and pull|Pulled back and |_Similar_ or - | directly outward. | forth. | nearly so. - | | | - Delta |To push bar to right | |Did before tuition - | with right hand. | | by pulling wire; - | | | after tuition by - | | | chance movement - | | | of head. - | | | - Theta |To pull bolt up with | |Pulled door and - | right hand. | | worked bolt loose. - | | | - Epsilon |To stand in front, | |Inserted arm in - | insert fingers of | | general activity - | right hand and | | while on top of - | press lever down. | | the box. - | | | - QQ (e) |To pull hook down. | |Pulled at the lever - | | | and hook in a - | | | general attack on - | | | the apparatus. - | | | - QQ (ff) |To pull wire loop | |Pulled outward on - | off nail with | | the lever which - | right hand. | | pushed the banana - | | | down the - | | | chute so hard as - | | | to pull it off its - | | | pivot. - | | | - WW |To stand on top of | |Pulled at door until - | box, reach right | | bar worked out - | hand down and | | of its catch. - | pull bar up. | | - ==========+=====================+===================+==================== - -I have kept the results of the tests of the ‘on chair’ type separate from -the others because they may be tests of a different thing and surely are -subject to different conditions. - -They were tests of the animals’ ability to form the habit of going to a -certain place by reason of having been _carried_ there and securing food -thereby. I would leave the animal loose in the room, and if he failed -in 5 or 10 minutes to go to the place of his own accord, would put him -back in his cage; if he did go of his own accord, I would note the time. -Then I would take him, carry him to the place, and feed him. After doing -this 10 times I would turn him loose again and see whether the idea of -being fed in such and such a place was present and active in making him -go to the place. In such tests we are absolutely sure that the animal can -without any difficulty perform the necessary movements and would in case -the proper stimulus to set them off appeared, if, for instance, a bit of -food on one of the places to which he was to go caught his eye. In so far -forth the tests were favorable cases for learning. On the other hand, the -situation associated with getting food may have been in these cases not -the mere ‘being on box’ but the whole previous experience ‘being carried -while clinging and being put or let jump on a box.’ In this respect the -tests may have been less favorable than the acts where getting food was -always the direct sequent of the act of going into the box. - -The experiments were:— - -A. Carrying the animal and putting him on a chair. - -B. Carrying the animal and putting him on a pile of boxes. - -C. Carrying the animal and putting him on the top of a sewing machine. - -D. Carrying the animal and putting him on the middle of a board 6 feet -long, stretched horizontally across the room, 3 feet from the floor. - -E. Carrying the animal and putting him on the side of the cage, head down. - -The results are given in Table 13. - -The size of the room in which I worked and other practical difficulties -prevented me from extending these experiments. As they stand, no stable -judgments can be inferred from them. It should be noted that in the -successful cases there were no other signs of the presence of the idea -‘food when there’ than the mere going to a certain place. The animal did -not wait at the place more than a second or two, did not look at me or -show any signs of expecting anything. - - -TABLE 13 - - ================+==========+==============+===============+=========== - EXPERIMENT | |RESULTS BEFORE|NUMBER OF TIMES| RESULTS - AND DATE | ANIMAL | TRAINING | PUT THROUGH | AFTER - | | | | TRAINING - ----------------+----------+--------------+---------------+----------- - A. Jan. 22, 1901| No. 1. | 5 F | 10 | 1.00 - | | | | 3.00 - Jan. 22, 1901| No. 1. | 5 F | 10 | im. - | | | | 3.30 - Jan. 23, 1901| No. 3. | 5 F | 10 | 3.30 - | | 5 F | | - B. Jan. 26, 1901| No. 1. | 10 F | 10 and 5 | 10 F 5 F - | No. 3. | 5 F | 10 | 5 F - | | | 10 | 5 F - C. Jan. 27, 1901| No. 1. | 5 F | 10 | 3.00 - D. Jan. 27, 1901| No. 1. | 3.20 | 10 | 5 F - E. Jan. 26, 1901| No. 3. | 5 F | 5 | 5 F - ================+==========+==============+===============+=========== - -Although, as I noted in the early part of this monograph, there were -occasionally phenomena in the general behavior of the monkeys which of -themselves impressed one as being suggestive of an ideational life, -the general run of their learning apart from the specific experiments -described was certainly confined to the association of impulses of their -own with certain situations. The following examples will suffice:— - -In getting them so that they would let themselves be handled it was of -almost no service to _take_ them and feed them while holding them or -otherwise make that state pleasant for them. By far the best way is to -wait patiently till they do come near, then feed them; wait patiently -till they do take hold of your arm, then feed them. If you do take them -and hold them partly by force, you must feed them only when they are -comparatively still. In short, in taming them one comes unconsciously -to adopt the method of rewarding certain of their impulses rather than -certain _conditions_ which might be associated in their minds with ideas, -had they such. - -After No. 1 and No. 3 had both reached a point where both could hardly -be gotten to leave me and go back into their cages or down to the floor -of the room, where they evidently enjoyed being held by me, they still -did not climb upon me. The idea of clinging to me was either absent or -impotent to cause them to act. What they did do was, in the case of -No. 1, to jump about, pawing around in the air, until I caught an arm -or leg, to which stimulus he had by dint of the typical sort of animal -association learned to react by jumping to my arm and clinging there; in -the case of No. 3, to stand still until I held my arm right in front of -him (if he were in his cage) or to come and stand on his hind legs in -front of me (if he were out on the floor). In both cases No. 3’s act was -one which had been learned by my rewarding his impulses. I often tried, -at this period of their intimacy with me, this instructive experiment. -The monkey would be clinging to me so that I could hardly tear him away. -I would do so, and he would, if dropped loose from me, make no efforts to -get back. - -I have already mentioned my failure to get the animals to put out their -right hands through the netting after they had long done so with their -left hands. With No. 3 I tried putting my fingers through and poking the -arm out and then making the movement with it. He profited little if any -by this tuition. Had I somehow induced him to do it himself, a few trials -would have been sufficient to get the habit well under way. - -Monkey No. 1 apparently enjoyed scratching himself. Among the stimuli -which served to set off this act of scratching was the irritation from -tobacco smoke. If any one would blow smoke in No. 1’s face, he would -blink his eyes and scratch himself, principally in the back. After a -time he got in the habit of coming to the front of his cage when any one -was smoking and making such movements and sounds as in his experience -had attracted attention and caused the smoker to blow in his face. He -was often given a lighted cigar or cigarette to test him for imitation. -He formed the habit of rubbing it on his back. After doing so he would -scratch himself with great vigor and zest. He came to do this always -when the proper object was given him. I have recounted all this to show -that the monkey enjoyed scratching himself. _Yet he apparently never -scratched himself except in response to some sensory stimulus._ He was -apparently incapable of thinking ‘scratch’ and so doing. Yet the act was -quite capable of association with circumstances with which as a matter -of hereditary organization it had no connection. For by taking a certain -well-defined position in front of his cage and feeding him whenever he -did scratch himself I got him to always scratch within a few seconds -after I took that position. - - -GENERAL MENTAL DEVELOPMENT OF THE MONKEYS - -It is to be hoped that the growing recognition of the worth of -comparative and genetic studies will lead to investigations of the mental -make-up of other species of monkeys, and to the careful overhauling of -the work done so far, including these rather fragmentary studies of mine. -Work with three monkeys of one species, especially when no general body -of phenomena, such as one has at hand in the case of domestic animals, -can be used as a means of comparison, must necessarily be of limited -application in all its details and of insecure application even in its -general features. What I shall say concerning the advance in the mental -development of the monkeys over that of other mammals may then be in -strictness true of only my three subjects, and it may be left to the -judgment of individuals to extend my conclusions as far as seems to them -likely. To me it seems fairly likely that the very general mental traits -which the research has demonstrated hold true with little variation in -the monkeys in general. - -The monkeys represent progress in mental development from the generalized -mammalian type toward man:— - -1. In their sensory equipment, in the presence of focalized vision. - -2. In their motor equipment, in the coördinated movements of the hand and -the eye. - -3. In their instincts or inherited nervous connections, in their general -physical and mental activity. - -4. In their method of learning or associative processes; in— - - _a._ Quicker formation of associations, - _b._ Greater number of associations, - _c._ Greater delicacy of associations, - _d._ Greater complexity of associations, - _e._ Greater permanence of associations. - -The fact of (1) is well known to comparative anatomists. Its importance -in mental development is perhaps not realized, but appears constantly to -a systematic student. - -(2) is what accounts for much of the specious appearance of human ways -of thinking in the monkeys and becomes in its human extension the handy -tool for much of our intellectual life. It is in great measure the -prerequisite of 4 _c_. - -(3) accounts for the rest of such specious appearances, is at the basis -of much of 4 _b_, presages the similar though extended instincts of the -human being, which I believe are the leading efficient causes of human -mental capacity, and is thus the great mental bond which would justify -the inclusion of monkeys and man in a common group if we were to classify -animals on the basis of mental characteristics. - -Even the casual observer, if he has any psychological insight, will be -struck by the general, aimless, intrinsically valuable (to the animal’s -feelings) physical activities of a monkey compared with the specialized, -definitely aroused, utilitarian activities of a dog or cat. Watch the -latter and he does but few things, does them in response to obvious -sense presentations, does them with practical consequences of food, -sex-indulgence, preparation for adult battles, etc. If nothing that -appeals to his special organization comes up, he does nothing. Watch a -monkey and you cannot enumerate the things he does, cannot discover the -stimuli to which he reacts, cannot conceive the _raison d’être_ of his -pursuits. Everything appeals to him. He likes to be active for the sake -of activity. - -The observer who has proper opportunities and takes proper pains will -find this intrinsic interest to hold of mental activity as well. No. 1 -happened to hit a projecting wire so as to make it vibrate. He repeated -this act hundreds of times in the few days following. He did not, could -not, eat, make love to, or get preliminary practice for the serious -battles of life out of, that sound. But it did give him mental food, -mental exercise. Monkeys seem to enjoy strange places; they revel, if I -may be permitted an anthropomorphism, in novel objects. They like to have -feelings as they do to make movements. The fact of mental life is to them -its own reward. - -It is beyond question rash for any one to venture hypotheses concerning -the brain parallel of mental conditions, most of all for the ignoramus -in the comparative histology of the nervous system, but one cannot help -thinking that the behavior of the monkeys points to a cerebrum that is -no longer a conservative machine for making a few well-defined sorts of -connections between sense-impressions and acts, that is not only fitted -to do more delicate work in parts, but is also alive, tender all over, -functioning throughout, set off in action by anything and everything. And -if one adds coördinations allowing a freedom and a differentiation of -action of the muscles used in speech comparable to that already present -in connection with the monkey’s hand, he may well ask, “What more of a -nervous mechanism do you need to parallel the behavior of the year-old -child?” However, this is not the place to speculate upon the importance -to human development of our instinctive aimless activity, physical and -mental, or to describe further its similarity and evident phylogenetic -relationship to the instinctive behavior of the monkeys. Elsewhere I -shall undertake that task. - -4. In their method of learning, the monkeys do not advance far beyond the -generalized mammalian type, but in their proficiency in that method they -do. They seem at least to form associations very much faster, and they -form very many more. They also seem superior in the delicacy and in the -complexity of the associations formed and the connections seem to be more -permanent. - -This progress may seem, and doubtless will to the thinker who looks upon -the human intellect as a collection of functions of which ideation, -judgment and reasoning are chief, to be slight. To my mind it is not -so in reality. For it seems to me highly probable that the so-called -‘higher’ intellectual processes of human beings are but secondary results -of the general function of having free ideas and that this general -function is the result of the formation after the fashion of the animals -of a very great number of associations. I should therefore say, “Let -us not wonder at the comparative absence of free ideas in the monkeys, -much less at the absence of inferences or concepts. Let us not wonder -that the only demonstrable intellectual advance of the monkeys over the -mammals in general is the change from a few, narrowly confined, practical -associations to a multitude of all sorts, for that may turn out to be at -the bottom the only _demonstrable advance of man_, an advance which in -connection with a brain acting with increased delicacy and irritability, -brings in its train the functions which mark off human mental faculty -from that of all other animals.” - -The typical process of association described in Chapter II has since been -found to exist among reptiles (by Mr. R. M. Yerkes) and among fishes (by -myself). It seems fairly likely that not much more characterizes the -primates. If such work as that of Lubbock and the Peckhams holds its own -against the critical studies of Bethe, this same process exists in the -insects. Yerkes and Bosworth think they have demonstrated its presence -in the crayfish. Even if we regard the learning of the invertebrates as -problematic, still this process is the most comprehensive and important -thing in mental life. I have already hinted that we ought to turn our -views of human psychology upside down and study what is now casually -referred to in a chapter on habit or on the development of the will, as -the general psychological law, of which the commonly named processes are -derivatives. When this is done, we shall not only relieve human mentality -from its isolation and see its real relationships with other forms; we -may also come to know more about it, may even elevate our psychologies -to the explanatory level and connect mental processes with nervous -activities without arousing a sneer from the logician or a grin from the -neurologist. - - - - -CHAPTER VI - -LAWS AND HYPOTHESES FOR BEHAVIOR - - -LAWS OF BEHAVIOR IN GENERAL - -_Behavior is predictable._ The first law of behavior, one fraction of -the general law of the uniformity of nature, is that with life and -mind, as with mass and motion, the same cause will produce the same -effect,—that _the same situation will, in the same animal, produce the -same response_,—and that _if the same situation produces on two occasions -two different responses, the animal must have changed_. - -Scientific students of behavior will, with few exceptions, accept this -law in theory, but in practice we have not fully used it. We have too -often been content to say that a man may respond in any one of several -ways to the same situation, or may attend to one rather than another -feature of the same object, without insisting that the man must in each -case be different, and without searching for the differences in him which -cause the different reactions. - -The changes in an organism which make it respond differently on different -occasions to the same situation range from temporary to permanent -changes. Hunger, fatigue, sleep, and certain diseases on the one hand, -and learning, immunity, growth and senility on the other, illustrate this -range. - -Behavior is predictable _without recourse to magical agencies_. It is, -of course, the case that any given difference between the responses -of an animal to the same situation depends upon some _particular_ -difference in the animal. Each immunity, for example, has its detailed -representation in an altered condition of the blood or other bodily -tissue. In general the changes in an animal which cause changes in its -behavior to the same situation are fully enumerated in a list of the -bodily changes concerned. That is, whatever changes may be supposed to -have taken place in the animal’s vital force, spiritual essence, or -other magical bases for life and thought, are useless for scientific -explanation and control of behavior. - -No competent thinker probably doubts this in the case of such changes -as are referred to by hunger, sleep, fatigue, so-called ‘functional’ -diseases and immunity, and those who do doubt it in the case of mental -growth and learning seem to represent an incomplete evolution from -supernatural, or rather infrascientific, thinking. There may be in -behavior a surplus beyond what would be predictable if the entire history -of every atom in the body was known—a surplus necessarily attributable to -changes in the animal’s incorporeal structure. But scientific thinkers -properly refuse to deliberately count upon such a surplus. - -_Every response or change in response of an animal is then the result of -the interaction of its original knowable nature and the environment._ -This may seem too self-evident a corollary for mention. It should be -so, but, unfortunately, it is not. Two popular psychological doctrines -exist in defiance of it. One is the doctrine that the movements of early -infancy are random, the original nature of the animal being entirely -indifferent as to what movement shall be made upon a given stimulus. But -no animal can have an original nature that does not absolutely prescribe -just what the response shall be to every stimulus. If the movements are -really random, they occur by virtue of some force that works at random. -If the movements are really the result of the action of the environment -on the animal’s nature, they are never random. A baby twiddles his thumbs -or waves his legs for exactly the same sort of reason that a chick pecks -at a worm or preens its wing. - -The other doctrine which witnesses to neglect of the axiom that behavior -is the creation of the environment, acting on the animal’s nature, is the -doctrine that the need for a certain behavior helps to create it, that -being in a difficulty tends in and of itself to make an animal respond so -as to end the difficulty. - -The truth is that to a difficulty the animal responds by whatever its -inherited and acquired nature has connected with the special form of -difficulty and that in many animals the one response of those thus -provided which relieves the difficulty is selected and connected more -firmly with that difficulty’s next appearance. The difficulty acts only -as a stimulus to the animal’s nature and its relief acts only as a -premium to the connection whereby it was relieved. The law of original -behavior, or the law of instinct, is then that _to any situation an -animal will, apart from learning, respond by virtue of the inherited -nature of its reception-, connection- and action-systems_. - -The inquiry into the laws of learning to be made in this essay is limited -to those aspects of behavior which the term has come historically to -signify, that is, to intellect, skill, morals and the like. - -For the purposes of this essay it is not necessary to decide just what -features of an animal’s behavior to include under intellect, skill, -morals and the like. The statements to be made will fit any reasonable -dividing line between behavior on the one side and mere circulation, -digestion, excretion and the like on the other. There should in fact -be no clear dividing line, since there is no clear gap between those -activities which naturalists have come to call behavior and the others. - -The discussion will include: First, a description of two laws of -learning; second, an argument to prove that no additional forces -are needed—that these two laws explain all learning; and third, an -investigation of whether these two laws are reducible to more fundamental -laws. I shall also note briefly the consequences of the acceptance of -these laws in one sample case, that of the study of mental evolution. - - -PROVISIONAL LAWS OF ACQUIRED BEHAVIOR OR LEARNING - -The Law of Effect is that: _Of several responses made to the same -situation, those which are accompanied or closely followed by -satisfaction to the animal will, other things being equal, be more firmly -connected with the situation, so that, when it recurs, they will be -more likely to recur; those which are accompanied or closely followed -by discomfort to the animal will, other things being equal, have their -connections with that situation weakened, so that, when it recurs, they -will be less likely to occur. The greater the satisfaction or discomfort, -the greater the strengthening or weakening of the bond._ - -The Law of Exercise is that: _Any response to a situation will, other -things being equal, be more strongly connected with the situation in -proportion to the number of times it has been connected with that -situation and to the average vigor and duration of the connections._ - -These two laws stand out clearly in every series of experiments on animal -learning and in the entire history of the management of human affairs. -They give an account of learning that is satisfactory over a wide range -of experience, so long as all that is demanded is a rough and general -means of prophecy. We can, as a rule, get an animal to learn a given -accomplishment by getting him to accomplish it, rewarding him when he -does, and punishing him when he does not; or, if reward or punishment are -kept indifferent, by getting him to accomplish it much oftener than he -does any other response to the situation in question. - -For more detailed and perfect prophecy, the phrases ‘result in -satisfaction’ and ‘result in discomfort’ need further definition, and the -other things that are to be equal need comment. - -By a satisfying state of affairs is meant one which the animal does -nothing to avoid, often doing such things as attain and preserve it. By a -discomforting or annoying state of affairs is meant one which the animal -commonly avoids and abandons. - -The satisfiers for any animal in any given condition cannot be determined -with precision and surety save by observation. Food when hungry, society -when lonesome, sleep when fatigued, relief from pain, are samples of the -common occurrence that what favors the life of the species satisfies its -individual members. But this does not furnish a completely valid rule. - -The satisfying and annoying are not synonymous with favorable and -unfavorable to the life of either the individual or the species. Many -animals are satisfied by deleterious conditions. Excitement, overeating, -and alcoholic intoxication are, for instance, three very common and very -potent satisfiers of man. Conditions useful to the life of the species -in moderation are often satisfying far beyond their useful point: many -conditions of great utility to the life of the species do not satisfy and -may even annoy its members. - -The annoyers for any animal follow the rough rule that alterations -of the animal’s ‘natural’ or ‘normal’ structure—as by cuts, bruises, -blows, and the like,—and deprivations of or interference with its -‘natural’ or ‘normal’ activities,—as by capture, starvation, solitude, -or indigestion,—are intolerable. But interference with the structure -and functions by which the species is perpetuated is not a sufficient -criterion for discomfort. Nature’s adaptations are too crude. - -Upon examination it appears that the pernicious states of affairs which -an animal welcomes are not pernicious _at the time, to the neurones_. We -learn many bad habits, such as morphinism, because there is incomplete -adaptation of all the interests of the body-state to the temporary -interest of its ruling class, the neurones. So also the unsatisfying -goods are not goods to the neurones at the time. We neglect many benefits -because the neurones choose their immediate advantage. The neurones must -be tricked into permitting the animal to take exercise when freezing or -quinine when in a fever, or to free the stomach from certain poisons. - -Satisfaction and discomfort, welcoming and avoiding, thus seem to be -related to the maintenance and hindrance of the life processes of the -neurones rather than of the animal as a whole, and to temporary rather -than permanent maintenance and hindrance. - -The chief life processes of a neurone concerned in learning are -absorption of food, excretion of waste, reception and conduction of the -nerve impulse, and modifiability or change of connections. Of these only -the latter demands comment. - -The connections formed between situation and response are represented by -connections between neurones and neurones, whereby the disturbance or -neural current arising in the former is conducted to the latter across -their synapses. The strength or weakness of a connection means the -greater or less likelihood that the same current will be conducted from -the former to the latter rather than to some other place. The strength or -weakness of the connection is a condition of the synapse. What condition -of the synapse it is remains a matter for hypothesis. Close connection -might mean protoplasmic union, or proximity of the neurones in space, or -a greater permeability of a membrane, or a lowered electrical resistance, -or a favorable chemical condition of some other sort. Let us call -this undefined condition which parallels the strength of a connection -between situation and response the intimacy of the synapse. Then the -modifiability or connection changing of a neurone equals its power to -alter the intimacy of its synapses. - -As a provisional hypothesis to account for what satisfies and what annoys -an animal, I suggest the following:— - -A neurone modifies the intimacy of its synapses so as to keep intimate -those by whose intimacy its other life processes are favored and to -weaken the intimacy of those whereby its other life processes are -hindered. The animal’s action-system as a whole consequently does nothing -to avoid that response whereby the life processes of the neurones other -than connection-changing are maintained, but does cease those responses -whereby such life processes of the neurones are hindered. - -This hypothesis has two important consequences. First: Learning by -the law of effect is then more fully adaptive for the neurones in the -changing intimacy of whose synapses learning consists, than for the -animal as a whole. It is adaptive for the animal as a whole only in so -far as his organization makes the neurones concerned in the learning -welcome states of affairs that are favorable to his life and that of his -species and reject those that are harmful. - -Second: A mechanism in the neurones gives results in the behavior of -the animal as a whole that seem beyond mechanism. By their unmodifiable -abandonment of certain specific conditions and retention of others, the -animal as a whole can modify its behavior. Their one rule of conduct -causes in him a countless complexity of habits. The learning of an animal -is an instinct of its neurones. - -I have limited the discussion to animals in whom the connection-system -is a differentiated organ, the neurones. In so far as the law of effect -operates in an animal whose connection-system is not anatomically -distinguishable and is favored and hindered in its life by the same -conditions that favor and hinder the life of the animal as a whole, -the satisfying and annoying will be those states of affairs which the -connection-system, whatever it be, maintains and abandons. - -The other things that have to be equal in the case of the law of effect -are: First, the frequency, energy and duration of the connection,—that -is, the action of the law of exercise; second, the closeness with which -the satisfaction is associated with the response; and, third, the -readiness of the response to be connected with the situation. - -The first of these accessory conditions requires no comment. A slightly -satisfying or indifferent response made often may win a closer connection -than a more satisfying response made only rarely. - -The second is most clearly seen in the effect of increasing the interval -between the response and the satisfaction or discomfort. Such an increase -diminishes the rate of learning. If, for example, four boxes were -arranged so that turning a button caused a door to open (and permit a cat -to get freedom and food) in one, five, fifty and five hundred seconds, -respectively, a cat would form the habit of prompt escape from the first -box most rapidly and would almost certainly never form that habit in the -case of the fourth. The electric shock administered just as an animal -starts on the wrong path or touches the wrong mechanism, is potent, but -the same punishment administered ten or twenty seconds after an act will -have little or no effect upon that act. - -Close temporal sequence is not the only means of insuring the connection -of the satisfaction with the response producing it. What is called -attention to the response counts also. If a cat pushes a button around -with its nose, while its main occupation, the act to which its general -‘set’ impels it, to which, we say, it is chiefly attentive, is that of -clawing at an opening, it will be less aided in the formation of the -habit than if it had been chiefly concerned in what its nose was doing. -The successful response is as a rule only a part of all that the animal -is doing at the time. In proportion as it is an eminent, emphatic part of -it, learning is aided. Similarly discomfort eliminates most the eminent, -emphatic features of the total response which it accompanies or shortly -follows. - -The third factor, the susceptibility of the response and situation to -connection, is harder to illustrate. But, apparently, of those responses -which are equally strongly connected with a situation by nature and -equally attended to, some are more susceptible than others to a more -intimate connection. - -The things which have to be equal in the case of the law of exercise -are the force of satisfyingness; that is, the action of the law of -effect, and again the readiness of the response to be connected with the -situation. - -The operation of the laws of instinct, exercise and effect is -conditioned further by (1) what may be called the law of assimilation or -analogy,—that a situation, especially one to which no particular response -is connected by original nature or previous experience, may connect with -whatever response is bound to some situation _much like it_,—and (2) by -the law of partial activity—that more or less of the total situation may -be specially active in determining the response. - -The first of these laws is a result of the facts that conduction in the -neurones follows the line of least resistance or closest connection, that -the action-system is so organized that certain responses tend to be made -in their totality if at all, and that slightly different situations may, -therefore, produce some one response, the effects of their differences -being in the accessories of that response. - -The second law is a result of the facts that the situation, itself a -compound, produces a compound action in the neurones, and that by reason -of inner conditions, the relative intensities of different parts of the -compound may vary. The commonest response will be that due to the modal -condition of the neural compound, but every condition of the compound -will have its response. - - -THE ADEQUACY OF THE LAWS OF EXERCISE AND EFFECT - -Behavior has been supposed to be modified in accordance with three -other principles or laws besides the law of exercise and the law of -effect. Imitation is often used as a name for the supposed law that the -perception of a certain response to a situation by another animal tends -in and of itself to connect that response to that situation. Common -acceptance has been given to more or less of the law that the idea of an -act, or of the result of an act, or of the immediate or remote sensations -produced by the act, tends in and of itself to produce the act. Such a -law of ‘suggestion’ or ‘ideo-motor’ action may be phrased differently, -but in whatever form, it insists that the bond between a situation and -some conscious representation of a response or of its consequences can do -the work of the bond between the situation and the response itself. In -acts of reasoning man has been supposed to connect with a given situation -a response that could never have been predicted merely from knowledge -of what responses were connected with that situation by his original -nature or had been connected with it by the laws of exercise and effect. -Inference has been supposed to create bonds in and of itself and to be -above the mere laws of habit. - -Various forms of statement, most of them vague, have been and would be -used in describing the potency of a perceived response, a thought-of -response, or a train of inference, to produce a response and bind it to -the given total situation. Any forms will do for the present argument, -since all forms mean to assert that responses can be and often are bound -to situations otherwise than by original bodily nature, satisfaction, -discomfort, disuse and use. I shall try to show that they cannot; that, -on the contrary, the laws of exercise and effect account for all learning. - -_The facts of imitation in human and animal behavior are explainable by -the laws of instinct, exercise and effect._ - -Some cases of imitation are undoubtedly mere instincts in which the -situation responded to is an act by another of the same species. If the -baby smiles at a smile, it is because of a special, inborn connection -between that sight and that act,—he smiles at a smile for just the same -reason that he draws down his mouth and wails at harsh words. At that -stage of his life he does not imitate other simple acts. A man runs -_with_ a crowd for the same reason that he runs _from_ a tiger. Returning -a blow is no more due to a general tendency to imitate than warding it -off is. - -Other cases of imitation are mere adjuncts to the ordinary process of -habit-formation. In the first place, the act of another, or its result, -may serve as a model by which the satisfyingness of one’s own responses -are determined. Just as the touch and taste of food tells a baby that -he has got it safely into his mouth, so the sound of a word spoken by -another or the sight of another performing some act of skill tells us -whether our pronunciation or technique is right or wrong. - -In the second place, the perception of another’s act may serve as a -stimulus to a response whereby the situation is altered into one to -which the animal responds from habit by an act like the one perceived. -For example, the perception of another making a certain response (_A_) -to a situation (_B_) may lead in me by the laws of habit to a response -(_C_) which puts me in a situation (_D_) such that the response (_A_) is -made by me by the laws of habit. Suppose that by previous training the -act of taking off my hat (_A_) has become connected as response to the -situation (_D_), ‘thought of hat off,’ and suppose that with the sight of -others uncovering their heads (_A_) in church (_B_) there has, again by -previous habituation, been connected, as response (_C_), ‘thought of hat -off.’ Then the sight of others uncovering their heads would by virtue of -the laws of habit lead me to uncover. Imitation of this sort, where the -perception of the act or condition in another gives rise to the idea of -performing the act or attaining the condition, the idea in turn giving -rise to the appropriate act, is certainly very common. - -There may be cases of imitation which cannot be thus accounted for as -special instinctive responses to the perception of certain acts by the -same acts, as habits formed under the condition that the satisfyingness -of a response is its likeness to the perceived act of another, or as the -connection of two habits, one of getting, from the perceived act of -another, a certain inner condition, the other of getting, from this inner -condition, the act in question. There may be, that is, cases where the -perceived act of another in and of itself creates a connection. - -It is apparently taken for granted by a majority of writers on human -behavior that cases of such direct mental infection, as it were, not -only exist, but are the rule. I am unable to find proof of such cases, -however. Those commonly quoted are far from clear. Learning to talk in -the human infant, for example, the stock case of imitation as a direct -means of learning, offers only very weak and dubious evidence. Since -what is true of it holds substantially for the other favored cases for -learning by imitation, I shall examine it at some length. - -Let us first be clear as to the alternative explanations of linguistic -imitation. The first is that seeing the movements of another’s -mouth-parts or hearing a series of word-sounds in and of itself produces -the response of making that series of sounds or one like it. - -The other is that the laws of instinct and habit are adequate to explain -the fact in the following manner: A child instinctively produces a great -variety of sounds and sound-series. Some of these, accepted as equal to -words by the child’s companions, are rewarded, so that the child learns -by the law of effect to use them in certain situations to attain certain -results. It is possible also that a child instinctively feels a special -satisfaction at babbling when spoken to and a special satisfaction at -finding the sound he makes like one that rings in the ears of memory -and has meaning. The latter would be like the instinctive satisfaction -apparently felt in constructing an object which is like some real object -whose appearance and meaning he knows. - -A child also meets frequently the situations ‘say dada,’ ‘say mama,’ ‘say -good night’ and the like,[41] and is rewarded when his general babble -produces something like the word spoken to him. He thus, by the law of -effect, learns to respond to any ‘say’ situation by making _some_ sound -and to each of many ‘say’ situations by making an appropriate sound, and -to feel satisfaction at duplicating these words when heard. According -to the amount of such training, the tendency to respond to words spoken -to him by making some sound may become very strong, and the number of -successful duplications very large. Satisfaction may be so connected -with saying words that the child practices them by himself orally and -even in inner speech. The second alternative relies upon the instinct -of babbling, and the satisfaction of getting desirable effects from -speech, either the effect which the word has by its meaning as a request -(‘water,’ ‘milk,’ ‘take me outdoors’ and the like) or the effect which it -has by its mere sound upon companions who notice, pet or otherwise reward -a child for linguistic progress. - -There are many difficulties in the way of accepting the first -alternative. First of all, no one can believe that _all_ of a child’s -speech is acquired by direct imitation. On many occasions the process is -undoubtedly one of the production of many sounds, irrespective of the -model given, and the selection of the best one by parental reward. Any -student who will try to get a child who is just beginning to speak, to -say cat, dog and mouse and will record the sounds actually made by the -child in the three cases, will find them very much alike. There will in -fact be little that even _looks_ like direct imitation until the child -has ‘learned’ at least forty or fifty words. - -The second difficulty lies in the fact that different children, in even -the clearest cases of the imitation of one sound, vary from it in so many -directions. A list of all the sounds made in response to one sound heard -is more suggestive of random babble as modified by various habits of -duplicating sounds, than of a direct potency of the model. Ten children -of the same age may, in response to ‘Christmas,’ say, kiss, kissus, -krismus, mus, kim, kimus, kiruss, i-us and even totally unlike vocables -such as hi-yi or ya-ya. - -The third difficulty is that in those features of word-sounds which are -hard to acquire, such as the ‘th’ sound, direct imitation is inadequate. -The teacher has recourse to trial and chance success, the spoken word -serving as a model to guide satisfaction and discomfort. In general no -sound not included in the instinctive babble of children seems to be -acquired by merely hearing and seeing it made. - -A fourth difficulty is that by the doctrine of direct imitation it should -not be very much more than two or three times as hard to repeat a two- -or three-syllable series as to repeat a single syllable. It is, in fact, -enormously harder. This is, of course, just what is to be expected if -learning a sound means the selection from random babbling plus previous -habits. If, for instance, a child makes thirty monosyllabic sounds -like pa, ga, ta, ma, pi, gi, li, mi, etc., there is, by chance, one -chance in thirty that in response to a word or phrase he will make that -one-syllable sound of his repertory which is most like it, but there is -only one chance in nine hundred that he will make that _two-syllable_ -combination of his repertory which is most like it. - -On the other hand, two objections will be made to the opposite view that -the word spoken acts only as a model to select from responses otherwise -caused, or as a stimulus to habits already existing. First it will be -said that clear, indubitable repetitions of words never practiced by -the child, either as totals or in their syllables separately, _do_ -occur,—that children do respond by repeating a word in cases where full -knowledge of all their previous habits would give no reason to expect -them to make such a connection. To this the only retort is that such -observations should be based on a very delicate and very elaborate record -of a child’s linguistic history, and that until they are so made, it is -wise to withhold acceptance. - -The second objection is that the rapid acquisition of a vocabulary -such as occurs in the second and third year is too great a task to be -accomplished by the laws of exercise and effect alone. This objection -is based on an overestimation of the variety of sounds which children -of the ages in question make. For example, a child who says 250 words, -including say 400 syllables, comprising say 300 syllables which, when -properly pronounced, are distinguishable, may actually use less than 50 -distinguishable syllables. _Ba_, may stand for the first syllable of -father, water, barn, park and the like. _Ki_ may stand for cry, climb, -and even carry. For a child to say a word commonly means that he makes -a sound which his intimate companions can recognize as his version of -that word. A child who can produce something like each one of a thousand -words upon hearing them, may do so from actual control over less than -a hundred syllables. If we suppose him to have acquired the habits, -first, of saying _something_ in such a case, second, of responding to a -certain hundred sounds when perceived or remembered by making, in each -case, a similar sound, and, third, of responding to any other sound when -perceived or remembered, by making that sound of his own repertory which -is most like it,[42] we can account for a thousand ‘imitations,’ and -still not have made a large demand upon childish powers of learning. - -No one should pretend to have disproved direct imitation in the case of -learning to talk until he has subjected all these and other matters to -crucial experiments. But the burden of proof does seem to belong upon -those who deny the adequacy of the laws of exercise and effect. In so far -as the choice is between accepting or rejecting a general law that, other -things being equal, the perception of a response in another produces that -response, we surely must reject it. Some of the cases of imitation may be -unexplained by the laws of exercise and effect. But for others no law of -imitation is required. And of what should happen by such a law not over a -trivial fraction at most does happen. - - _The idea of a response is in and of itself unable to produce - that response._ - -The early students of behavior, considering human behavior and -emphasizing behavior that was thought about and purposive, agreed that -the sure way to connect a response with a situation was to choose, or -will, or consent to, that response. Later students still agreed that -to think about the response in some way, to have an image of it or of -the sensations caused in you by previous performances of it, was a -strong provocative to it. To get a response, get some sort of conscious -representative of it, has been an acceptable maxim. Medicine, education -and even advertising have based their practice upon the theory that ideas -tended to issue in the particular sort of acts that they were ideas of. - -The laws of exercise and effect, on the contrary, if they are the sole -laws of modifiability, insist that the thought of an act will produce -that act only if the act has been connected with that thought (and -without resulting discomfort) in the animal’s past. - -It seems plausible that there should be a peculiar bond between the -thought of a response and the response. The plausibility is due to two -reasons, one of which is sound but inadequate, the other being, in my -opinion, entirely unsound. The first reason is that, as a mere matter -of fact, the thought of a response does so often produce it. The second -is that an idea of a response seems a natural and sufficient cause for -it to appear. The first reason is inadequate to justify any law of the -production of a response by its image or other representative, since -evidence can be found to show that when a response is produced by an -idea of it, it has been already bound to that idea by repetition or -satisfaction. The second reason is unsound because, even if responses are -brought to pass occasionally by their images, that is surely an extremely -rare and unnatural method. - -It is certain that in at least nine cases out of ten a response is -produced, not by an image or other representation of it, but by a -situation nowise like it or any of its accessories. Hunger and the -perception of edible objects, far outweigh ideas of grasping, biting and -swallowing, as causes of the eating done in the world. Objects sensed, -not images of eye-movements, cause a similar overwhelming majority of -the eye’s responses. We walk, reach and grasp on most occasions, not -because of anticipatory images of how it will feel to do so or verbal -descriptions to ourselves of what we are to do, but because we are -stimulated by the perception of some object. - -It is also certain that the idea of a response may be impotent to -produce it. I cannot produce a sneeze by thinking of sneezing. A child -may have, in the case of some simple bodily act, which he has done in -response to certain situations thousands of times, as adequate ideas of -it as are possessed by others, and yet be utterly unable to make himself -do it; many adults show this same phenomenon, for instance, in the case -of swallowing a pill. And, of course, one can have ideas of running a -mile in two minutes, jumping a fence eight feet high, or drawing a line -exactly equal to a hundred millimeter line, just as easily as of running -the mile in ten minutes, or jumping four feet. - -It is further certain that the thought of doing one thing very often -results in the man’s doing something quite different. The thought of -moving the eyes smoothly without stops along a line of print has occurred -to many people, who nevertheless actually did as a result move the eyes -in a series of jumps with long stops. - -It is further certain that in many cases where an animal does connect a -given response with the image or thought of that response, the connection -has been built up by the laws of exercise and effect. Such cases as -appropriate responses to, ‘I will go to bed,’ ‘I will get up,’ ‘I will -eat,’ ‘I will write a letter,’ ‘I will read,’ or to the corresponding -commands, requests or suggestions, are observably built up by training. -The appropriate response follows the idea only if it has, by repetition -or reward, been connected with it or something like it. If the only -requirement in moral education were to have the idea of the right act -at the right time, the lives of teachers and parents would be greatly -alleviated. But the decision to get up, or the idea of getting up or of -being up, is futile until the child has connected therewith the actual -act of getting up. - -The defender of the direct potency of conscious representatives of a -response to produce it may be tempted to complain at this point that what -the laws of exercise and effect do is to reduce the strength of competing -ideas, and leave the idea, say of getting up, free to exercise its direct -potency. The complaint shows a weak sense for fact. The ordinary child is -not a Hamlet, nor is he beguiled by the imagined delights of staying in -bed, nor repelled by the image of getting up out of it. On the contrary, -he may be entirely willing to _think of_ getting up. It is the actual -delights that hold him, the actual discomforts that check him, and the -only way to be sure that he will get up is so to arrange matters that it -is more satisfactory to him to get up than not to when the situation, -whatever it be, that is to suggest that response, makes its appearance. - -The experience of every schoolroom shows that it is not enough to get the -idea of an act. The act must have gone with that idea or be now put with -it. The bond must be created. Responses to the suggestions of language, -whether addressed to us by others or by ourselves in inner speech, in -a very large majority of cases owe their bonds to the laws of exercise -and effect. We learn to do what we are told, or what we tell ourselves, -by doing _something_ and rejecting or retaining what we do by virtue -of its effects. So also in the case of a majority of responses to the -suggestions of other than verbal imagery. - -The idea of a response, like the perception of a response by another, -acts often as a guide to response _ex post facto_ by deciding what shall -be satisfying. Where superficial inspection leaves the impression that -the idea creates the act, a little care often shows it to have only -selected from the acts produced by instinct and habit. For example, let -the reader think of some act never performed hitherto, such as putting -his left middle finger upon the upper right hand corner of this page, -and make the movement. It may seem at first sight that having the idea -entirely unopposed was the sufficient cause of the act. But careful -experiment, including, for instance, the closure of the eyes and -anesthesia of the fingers will reveal that the original propulsion of the -idea is not to just that act, but to many possibilities, and that its -chief potency lies in the fact that not to get the finger to that point -is annoying, and that consequently the organism is at peace only when the -act is done. - -So far it has been shown that: The majority of responses are not produced -by ideas of them. The idea of a response may be impotent to produce it. -The idea of one act may produce a different, even an opposite act. When -an idea seems to produce a response in and of itself, it may really act -by determining the satisfyingness of responses otherwise made. These -facts are sufficient to destroy the pretensions of any general law that -the image of an act will, other things being equal, produce it. But the -possibility that such an image may occasionally exercise this peculiar -potency remains. - -I despair of convincing the reader that it does not. Man is the -only animal possessing a large fund of ideas of acts, and man’s -connection-system is so complex and his ideas of acts are so intricately -bound to situations that have by use and effect produced those acts, -that the proof of this negative is a practical impossibility. But it is -possible to show that even the most favored cases for the production of a -response by securing an ideal representation of it may be explainable by -use and effect alone. - -The extreme apparent potency of ideas representing acts to produce them -regardless of bonds of use or effect is, of course, witnessed in the -phenomena of suggestion in hypnosis and allied states. To try to reduce -these phenomena to consequences of the laws of habit may seem fanatical. -Here, it will be said, are the crucial cases where the idea of an act, if -freed from all effects of opposing ideas, does inevitably produce the act -so far as it is a possibility for the animal’s action-system. - -That is precisely what I cannot find proof of. - -Efficient suggestions to hypnotized subjects, on the contrary, are often -ambiguous in the sense that they seem as likely to arouse a situation -_to which the act has been bound by the law of habit_ as to arouse an -idea of the act. Often they are far better suited to the former purpose. -Direct commands—Walk, Dance, Get up, Sit down—obviously will operate by -the law of habit provided the situations connected with disobedience are -excluded. This is also the case with such indirect suggestions as ‘This -is a knife (stick).’ ‘This is your sword (broom).’ ‘Have a cigar (a pen).’ - -The release of a suggestion from inhibitions may as well be the release -from _ideas connected as antecedents with_ not performing the act as -the release from _ideas of_ not performing it. It is a question of fact -whether, to get an act done by the subject, one must arouse in him an -idea to which or to a part of which or to something like which the act -has been bound by use or effect, or may arouse simply an idea of the act. - -Finally, if an idea has a tendency to connect with a certain response, -over and above the bonds due to exercise and effect, it should _always_ -manifest that tendency. If the connection is not made, it must be due to -the action of some contrary force. It is less my duty to show that the -laws of habit can account for hypnotic suggestibility, obsessions, and -the like, than it is my opponents’ duty to explain why a man can spend a -half day in hospitably welcoming a hundred ideas of acts and yet perform -no one of them, save those in the case of which he has learned to do the -thing when he thinks of doing it. Again, how can the mere addition of -the idea of a future date to the idea of an act so utterly deprive it of -present potency. - -In view of all these facts it seems probable that ideas of responses act -in connection just as do any other situations, and that the phenomena of -suggestion and ideo-motor action really mean that any idea will, except -for competing ideas, produce the response, not that _is like it_, but -that _has gone with it_, or with some idea like it. - - _Rational connections are, in their causation, like any others, - the difference being in what is connected._ - -It remains to ask whether situation and response are bound together in -the case of reasoning by any other forces than the forces of repetition, -energy and satisfaction? Do the laws of inferential thinking transcend -the laws of exercise and effect? Or does the mind, even in these novel -and constructive responses, do only what it is forced to do by original -nature or has done without discomfort? - -To defend the second alternative involves the reduction of the processes -of abstraction, association by similarity and selective thinking to mere -secondary consequences of the laws of exercise and effect. This I shall -try to do. - -The gist of the fact of abstraction is that response may be made to some -elements or aspects of a situation which have never been experienced -in isolation, and may be made to the element in question regardless of -the gross total situation in which it inheres. A baby thus learns to -respond to its mother’s face regardless of what total visual field it is -a part of. A child thus learns to respond by picking out any red object, -regardless of whether the redness be in an apple, a block, a pencil, a -ribbon or a ball. A student thus learns to respond to any plane surface -inclosed by three straight lines regardless of its size, shape, color or -other than geometrical meaning. - -What happens in such cases is that the response, by being connected with -many situations alike in the presence of the element in question and -different in other respects, is bound firmly to that element and loosely -to each of its concomitants. Conversely any element is bound firmly to -any one response that is made to all situations containing it and very, -very loosely to each of those responses that are made to only a few of -the situations containing it. The element of triangularity, for example, -is bound firmly to the response of saying or thinking ‘triangle’ but only -very loosely to the response of saying or thinking white, red, blue, -large, small, iron, steel, wood, paper and the like. A situation thus -acquires bonds not only with some response to it as a gross total, but -also with responses to each of its elements that has appeared in any -other gross totals. - -Appropriate response to an element regardless of its concomitants is a -necessary consequence of the laws of exercise and effect if an animal -learns to make that response to the gross total situations that contain -the element and not to make it to those that do not. Such prepotent -determination of the response by one or another element of the situation -is no transcendental mystery, but, given the circumstances, a general -rule of all learning. The dog who responds appropriately to ‘beg’ no -matter when, where, or by whom spoken, manifests the same laws of -behavior. There is no difficulty in understanding how each element of a -situation may come to tend to produce a response peculiar to it as well -as to play its part in determining the response to the situation as a -total. There may be some difficulty in understanding how each element -of a situation comes to be _felt_ whereas before only the gross total -was felt. The change in consciousness from the ‘big, blooming, buzzing -confusion’ to an aggregate of well-defined percepts and images, which -accompanies the change in behavior from response to totals to response to -parts or elements, may be mysterious. With the change in consciousness, -however, we are not now concerned. The _behavior_ of man and other -animals toward the abstract elements of color, size, number, form, time -or value is explained by the laws of instinct, exercise and effect. - -When the perception or thought of a fact arouses the thought of some -other fact identical in part with the former fact, we have so-called -association by similarity. An element of the neurone-action is prepotent -in determining the succeeding neurone-action. The particular way in which -it determines it is by itself continuing and making connection with other -associates. These it possesses by virtue of the law of exercise and -effect. - - * * * * * - -The changes in behavior classified under intellect and morality seem -then to be all explainable by the two laws of exercise and effect. The -facts of imitation really refer to certain specific original connections -or to the efficiency of a model in determining what shall satisfy or -to the provision of certain instructive situations in the form of the -behavior of other animals. The facts variously referred to as suggestion, -ideo-motor action or the motor power of ideas, really refer to the fact, -common in the human animal only, that to those ideas that represent acts -in thought the acts are often bound as responses. The bonds are due to -the primary laws of effect and exercise. The facts of reasoning really -refer to the fact of prepotency of one or another element in a situation -in determining the response. - -The reduction of all learning to making and rewarding or avoiding and -punishing connections between situation and response allows changes in -intellect and character to be explained by changes in the neurones that -are known either to be or to be possible. I have elsewhere sketched one -such possible neural mechanism for the law of effect.[43] - -On the contrary, imitation, suggestion and reasoning, as commonly -described, put an intolerable burden upon the neurones. To any one who -has tried to imagine a possible action in the neurones to parallel the -traditional power of the mere perception of an act in another or of the -mere representation of an act as done by oneself to produce that act, -this is a great merit. For the only adequate psychological parallel of -traditional imitation and suggestion would be the original existence or -the gratuitous formation of a connection between (1) each neurone-action -corresponding to a percept of an act done by another or to the idea of -an act done by oneself and (2) the neurone-action arousing that act. It -is incredible that the neurone-action corresponding to the perception of -a response in another, or to the idea of a response in oneself, or to -the first term in an association by similarity, should have, in and of -itself, a special power to determine that the next neurone-action should -be that paralleling the response in question. And there is no possible -physiological parallel of a power to jump from premise to conclusion for -no other reason than the ideal fitness of the sequence. - - -SIMPLIFICATIONS OF THE LAWS OF EXERCISE AND EFFECT - -There has been one notable attempt to explain the facts of learning by -an even simpler theory than that represented in the laws of exercise -and effect. Jennings has formulated as an adequate account of learning -the law that: “When a certain physiological state has been resolved, -through the continued action of an external agent, or otherwise, into -a second physiological state, this resolution becomes easier, so that -in course of time it takes place quickly and spontaneously” (‘Behavior -of the Lower Organisms,’ p. 289). “The law may be expressed briefly as -follows:—_The resolution of one physiological state into another becomes -easier and more rapid after it has taken place a number of times._ Hence -the behavior primarily characteristic for the second state comes to -follow immediately upon the first state. The operations of this law are, -of course, seen on a vast scale in higher organisms in the phenomena -which we commonly call memory, association, habit formation and learning” -(_ibid._, p. 291). This law may be expressed conveniently as a tendency -of a series of states - - A -> B -> C -> D - -to become - - A -> D - -or - - A -> B¹ -> C¹ -> D - -B¹ and C¹ being states B and C passed rapidly and in a modified way so -that they do not result in a reaction but are resolved directly into D. - -If Professor Jennings had applied to this law the same rigorous analysis -which he has so successfully employed elsewhere, he would have found that -it could be potent to cause learning only if supplemented by the law of -effect and then only for a fraction of learning. - -For, the situations being the same, the state A cannot produce, at one -time, now B and, at another time, abbreviated, rudimentary B¹ instead of -B. If A with S produces B once, it must always. If D or a rudimentary B¹ -is produced, there must be something other than A; A must itself have -changed. Something must have been added to or subtracted from it. In -Professor Jennings’ own words, “Since the external conditions have not -changed, the animal itself must have changed” (_ibid._, p. 286). And in -adaptive learning something related to the results of the S A connection -must have changed it. - -The series A—B—C—D does not become the series A—D or A—B¹—C¹—D by magic. -If B and C are weakened and D is strengthened as sequents of A in -response to S, it is because something other than repetition acts upon -them. Repetition alone could not blow hot for D and cold for B. - -Moreover, as a mere matter of fact, “the resolution of one physiological -state into another” through intermediate states does not with enough -repetition “become easier so that in course of time it takes place -quickly and spontaneously.” - -Paramecium does not change its response to, say, an obstacle in the -water, from swimming backward, turning to one side and swimming forward -by abbreviating and eventually omitting the turn and the backward -movement. The schoolboy does not tend to count 1, 2, 10 or to say a, b, -z, or give ablative plurals after nominative singulars. - -Repetition of a series of physiological states in and of itself on the -contrary makes an animal increasingly _more_ likely to _maintain_ the -series _in toto_. It is hard to give the first and then the last word of -an oft repeated passage like Hamlet’s soliloquy or the Lord’s Prayer, or -to make readily the first and then the last movement of writing a name or -address. Repetition never eliminates absolutely and eliminates relatively -the _less_ often or _less_ emphatically connected. - -Even if supplemented by the law of effect, so that some force is at hand -to change the effect of S upon the animal to A D instead of the original -A B C D, the law of the resolution of physiological states would be -relevant to only a fraction of learning. For example, let a cat or dog be -given an ordinary discrimination experiment, but so modified that whether -the animal responds by the ‘right’ or the ‘wrong’ act _he is removed -immediately after the reward or punishment_. That is, the event is either -S R1 or S R2, never S R1 R2. Let the experiment be repeated at intervals -so long that the physiological state, St. R1, or St. R2, leading to the -response R1 or R2 in the last trial, has ceased before the next. The -animal will come to respond to S by R2 only, though R2 has never been -reached by the ‘resolution’ of S R1 R2. - -Cats in jumping for birds or mice, men in playing billiards, tennis or -golf, and many other animals in many other kinds of behavior, often learn -as the dog must in this experiment. The situation on different occasions -is followed by different responses, but by only one per occasion. -Professor Jennings was misled by treating as general the special case -where the situation itself includes a condition of discomfort terminable -only by a ‘successful’ response or by the animal’s exhaustion or death. - -Assuming as typical this same limited case of response to an annoying -situation, so that success consists simply in replacing the situation -by another, Stevenson Smith reduces the learning-process to the law of -exercise alone. He argues that,— - -“For instance, let an organism at birth be capable of giving N reactions -(a, b, c, ... N) to a definite stimulus S and let only one of these -reactions be appropriate. If only one reaction can be given at a time -and if the one given is determined by the state of the organism at the -time S is received, there is one chance in N that it is the appropriate -reaction. When the appropriate reaction is finally given, the other -reactions are not called into play, S may cease to act, but until the -appropriate reaction is given let the organism be such that it runs -through the gamut of the others until the appropriate reaction is brought -about. As there are N possible reactions, the chances are that the -appropriate reaction will be given before all N are performed. At the -next appearance of the stimulus, which we may call S₂, those reactions -which were in the last case performed, are, through habit, more likely to -be again brought about than those which were not performed. Let _u_ stand -for the unperformed reactions. Then we have N - _u_ probable reactions -to S₂. Habit rendering the previously most performed reactions the most -probable throughout we should expect to find the appropriate reaction in -response to - - S₁ contained in N. - S₂ contained in N - _u₁_. - S₃ contained in N - _u₁_ - _u₂_. - ... - S_ₙ_ contained in N - _nu_, which approaches _one_ as a limit. - -Thus the appropriate reaction would be fixed through the laws of chance -and habit. This law of habit is that when any action is performed -a number of times under certain conditions, it becomes under those -conditions more and more easily performed” (_Journal of Comparative -Neurology and Psychology_, 1908, Vol. XVIII, pp. 503-504). - -This hypothesis is, like Professor Jennings’, adequate to account for -only the one special case, and is adequate to account for that only -upon a further limitation of the number of times that the animal may -repeat any one of his varied responses to the situation before he has -gone through them all once, or reached the one that puts an end to the -situation. - -The second limitation may be illustrated in the simple hypothetical case -of three responses, 1, 2 and 3, of which No. 2 is successful. Suppose the -animal always to go through his repertory with _no_ repetitions until he -reaches 2 and so closes the series. - -Only the following can happen:— - - 1 2 - 1 3 2 - 2 - 2 - 3 1 2 - 3 2 - -and, in the long run, 2 will happen twice as often as 1 or 3 happens. - -Suppose the animal to repeat each response of his repertory six times -before changing to another, the remaining conditions being as above. Then -only the following can happen:— - - 1 1 1 1 1 1 2 - 1 1 1 1 1 1 3 3 3 3 3 3 2 - 2 - 2 - 3 3 3 3 3 3 1 1 1 1 1 1 2 - 3 3 3 3 3 3 2, - -and in the long run 2 will happen one third as often as 1 or 3 and, -though always successful, must, by Smith’s theory, appear later and -later, so that if the animal meets the situation often enough, he will -eventually fail utterly in it! - -Animals do, as a matter of fact, commonly repeat responses many times -before changing them,[44] so that if only the law of exercise operated, -learning would not be adaptive. It is the _effect_ of 2 that gives it the -advantage over 1 and 3. Of two responses to the same annoying situation, -one continuing and the other relieving it, an animal could never learn to -adopt the latter as a result of the law of exercise alone, if the former -was, originally, twice as likely to occur. 1 1 2 would occur as often -as 2 and exercise would be equal for both. The convincing cases are, of -course, those where learning equals the strengthening to supremacy of an -originally very weak connection and the weakening of originally strong -bonds. An animal’s original nature may lead it to behave as shown below:— - - 1 1 1 3 1 1 4 1 1 2 - 1 1 1 1 3 1 1 1 3 1 1 4 2 - 4 1 1 3 3 1 1 4 4 1 1 1 1 1 2, etc., - -and yet the animal’s eventual behavior may be to react to the situation -always by 2. The law of effect is primary, irreducible to the law of -exercise. - - -THE EVOLUTION OF BEHAVIOR - -The acceptance of the laws of exercise and effect as adequate accounts of -learning would make notable differences in the treatment of all problems -that concern learning. I shall take, to illustrate this, the problem of -the development of intellect and character in the animal series, the -phylogenesis of intellectual and moral behavior. - -The difficulties in the way of understanding the evolution of -intellectual and moral behavior have been that neither what had been -evolved nor that from which it had been evolved was understood. - -The behavior of the higher animals, especially man, was thought to be -a product of impulses and ideas which got into the mind in various -ways and had power to arouse certain acts and other ideas more or -less mysteriously, in the manner described by the laws of ideo-motor -action, attention, association by contiguity, association by similarity, -suggestion, imitation, dynamo-genesis and the like, with possibly a -surplus of acts and ideas due to ‘free will.’ The mind was treated as -a crucible in which a multifarious solution of ideas, impulses and -automatisms boiled away, giving off, as a consequence of a subtle -chemistry, an abundance of thoughts and movements. Human behavior was -rarely viewed from without as a series of responses bound in various -ways to a series of situations. The student of animal behavior passed as -quickly as might be from such mere externals to the inner life of the -creature, making it his chief interest to decide whether it had percepts, -memories, concepts, abstractions, ideas of right and wrong, choices, -a self, a conscience, a sense of beauty. The facts in intellect and -character that are due to learning, that are not the inherited property -of the species and that consequently are beyond the scope of evolution -in the race, were not separated off from the facts of original nature. -The comparative psychologist misspent his energy on such problems as the -phylogenesis of the idea of self, moral judgments, or the sentiment of -filial affection. - -At the other extreme, the behavior of the protozoa was either -contemplated in the light of futile analogies,—for instance, between -discriminative reactions and conscious choice, and between inherited -instincts and memory,—or studied crudely in its results without -observation of what the animals really did. The protozoa were regarded -either as potential ‘conscious selves’ or as drifting lumps turned hither -and thither by the direct effects of light, heat, gravity and chemical -forces upon their tissues. - -The evolution of the intellectual and moral nature which a higher animal -really possesses from the sort of a nature which the real activities of -the protozoa manifest, is far less difficult to explain. - -In so far as the higher animal is a collection of original tendencies -to respond to physical events without and within the body, subject to -modification by the laws of exercise and effect and by these alone, -and in so far as the protozoan is already possessed of a well-defined -repertory of responses connected with physical events without and within -the body in substantially the manner of the higher animal’s original -tendencies, the problems of the evolution of behavior are definite and in -the way of solution. - -The previous sections gave reason for the belief that the higher animals, -including man, manifest no behavior beyond expectation from the laws -of instinct, exercise and effect. The human mind was seen to do no -more than connect in accord with original bonds, use and disuse, and -the satisfaction and discomfort resulting to the neurones. The work -of Jennings has shown that the protozoa already possess full-fledged -instincts, homologous with the instincts of man. They too may have -specialized receptors, an action-system with a well-defined repertory and -a connecting system or means of influencing the bonds between the stimuli -received and the motor reactions made. The difficulties of tracing the -possible development of a super-man from an infra-animal thus disappear. - -There is, of course, an abundance of _bona fide_ difficulty in -discovering the unlearned behavior of each group of animals and in -tracing, throughout the animal series, changes in the physical events to -which animals are sensitive so that to each a different response may be -attached, changes in the movements of which animals are capable, and -changes in the bonds by which particular movements follow particular -physical events. To find when and how animals whose natures remained -nearly or quite unchanged by the satisfying and annoying effects of their -behavior, gave birth to animals that could learn, is perhaps a still -harder task. But these tasks concern problems that are intelligible -matters of fact. They do not require a student to get out of matter -something defined as beyond matter, or to get volition out of tropisms, -or to get ideas of space and time out of swimming and sleeping. - -The evolution of the sensitivities and of the action-systems of animals -has already been subjected to matter-of-fact study by naturalists. The -evolution of the connection-system will soon be. Each reflex, instinct -or capacity, each bond between a given situation presented to a given -physiological state and a given response, has its ancestral tree. -Scratching at an irritated spot on the skin is older than arms. Following -an object that is moving slowly does not have to be explained separately, -as a ‘chance’ variation in dogs, sheep and babies. The mechanical trades -of man are related to the miscellaneous manipulations of the apes. Little -as we know of the connection-systems possessed by animals, we know enough -to be sure that a bond between situation and response has ancestors and -children as truly as does any bodily organ. Professor Whitman a decade -ago showed the possibility of phylogenetic investigation of instinctive -connections in a study which should be a stimulus and model for many -others. In place of any further general account of the study of the -phylogeny of the connection-system, I shall quote from his account of the -concrete phylogeny of the instinct of incubation. - - “_b. The Incubation Instinct_ - - 1. _Meaning to be Sought in Phyletic Roots._—It seems quite - natural to think of incubation merely as a means of providing - the heat needed for the development of the egg, and to assume - that the need was felt before the means was found to meet it. - Birds and eggs are thus presupposed, and as the birds could - not have foreseen the need, they could not have hit upon the - means except by accident. Then, what an infinite amount of - chancing must have followed before the first ‘cuddling’ became - a habit, and the habit a perfect instinct! We are driven to - such preposterous extremities as the result of taking a purely - casual feature to start with. Incubation supplies the needed - heat, but that is an incidental utility that has nothing to do - with the nature and origin of the instinct. It enables us to - see how natural selection has added some minor adjustments, but - explains nothing more. For the real meaning of the instinct we - must look to its phyletic roots. - - If we go back to animals standing near the remote ancestors of - birds, to the amphibia and fishes, we find the same instinct - stripped of its later disguises. Here one or both parents - simply remain over or near the eggs and keep a watchful guard - against enemies. Sometimes the movements of the parent serve to - keep the eggs supplied with fresh water, but aëration is not - the purpose for which the instinct exists. - - 2. _Means Rest and Incidental Protection to Offspring._—The - instinct is a part of the reproductive cycle of activities, - and always holds the same relation in all forms that exhibit - it, whether high or low. It follows the production of eggs, - or young, and means primarily, as I believe, rest, with - incidental protection to offspring. That meaning is always - manifest, no less in worms, molluscs, crustacea, spiders and - insects, than in fishes, amphibia, reptiles and birds. The - instinct makes no distinction between eggs and young, and that - is true all along the line up to birds, which extend the same - blind instinct to one as to the other. - - 3. _Essential Elements of the Instinct._—Every essential - element in the instinct of incubation was present long - before the birds and eggs arrived. These elements are: - (1) the disposition to remain with or over the eggs; (2) - the disposition to resist and drive away enemies; and (3) - periodicity. The birds brought all these elements along in - their congenital equipment, and added a few minor adaptations, - such as cutting the period of incubation to the need of normal - development, and thus avoiding indefinite waste of time in case - of sterile or abortive eggs. - - (1) _Disposition to Remain over the Eggs._—The disposition to - remain over the eggs is certainly very old, and is probably - bound up with the physiological necessity for rest after a - series of activities tending to exhaust the whole system. If - this suggestion seems far-fetched, when thinking of birds, it - will seem less so as we go back to simpler conditions, as we - find them among some of the lower invertebrate forms, which are - relatively very inactive and predisposed to remain quiet until - impelled by hunger to move. Here we find animals remaining - over their eggs, and thus shielding them from harm, from sheer - inability or indisposition to move. That is the case with - certain molluscs (_Crepidula_), the habits and development of - which have been recently studied by Professor Conklin. Here - full protection to offspring is afforded without any exertion - on the part of the parent, in a strictly passive way that - excludes even any instinctive care. In _Clepsine_ there is a - manifest unwillingness to leave the eggs, showing that the - disposition to remain over them is instinctive. If we start - with forms of similar sedentary mode of life, it is easy to see - that remaining over the eggs would be the most likely thing - to happen, even if no instinctive regard for them existed. - The protection afforded would, however, be quite sufficient - to insure the development of the instinct, natural selection - favoring those individuals which kept their position unchanged - long enough for the eggs to hatch.”[45] - - Professor Whitman proceeds to study the ‘Disposition to Resist - Enemies’ and the ‘Periodicity’ in the same genetic way. - -The most important of all original abilities is the ability to learn. It, -like other capacities, has evolved. The animal series shows a development -from animals whose connection-system suffers little or no permanent -modification by experience to animals whose connections are in large -measure created by use and disuse, satisfaction and discomfort. - -Some of this development can be explained without recourse to differences -in mere power to learn, by the fact that the latter animals are given -greater stimuli to or rewards for learning. But part of it is due to -differences in sheer ability to learn, that is, in the power of equally -satisfying conditions to strengthen or of equally annoying conditions to -weaken bonds in the animals’ connection-systems. This may be seen from -the following simple and partial case:— - -Call 1 and 2 two animals. - -Call C₁ and C₂ the internal conditions of the two animals except for -their connection-systems, each being the average condition of the animal -in question. - -Call S₁ and S₂ two external states of affairs, each being near the -indifference point for the animal in question,—that is, being one which -the animal does little to either avoid or secure. - -Call G₁ and G₂ two responses which result in O₁ and O₂ the _optima_ or -most satisfying state of affairs for 1 and 2. - -Call I₁ and I₂ two responses which result in the continuation of S₁ and -S₂. - -The only responses possible for 1 are G₁ and I₁. - -The only responses possible for 2 are G₂ and I₂. - -Animal 1 upon the recurrence of S₁ and C₁ is little or no more likely to -respond by G₁ than he was before. - -Animal 2 upon the recurrence of S₂ and C₂ is far more likely to respond -by G₂ than he was before. - -The fact thus outlined might conceivably be due to an intrinsic -inequality between O₁ and O₂, the power of equally satisfying _optima_ to -influence, their antecedents being identical. This is not the case in the -evolution of learning, however. For even if, instead of O₂, we had only -a moderately satisfying state of affairs, such as the company of other -chicks to (2) a 15-day-old chick, while O₁ was the optimum of darkness, -dampness, coolness, etc., for (1) an earthworm, 2 would learn far, far -more rapidly than 1. - -The fact is due, of course, to the unequal power of equally satisfying -conditions to influence their antecedents. The same argument holds good -for the influence of discomfort. - -The ability to learn,—that is, the possession of a connection-system -subject to the laws of exercise and effect,—has been found in animals as -‘low’ as the starfish and perhaps in the protozoa. It is hard to tell -whether the changed responses observed in Stentor by Jennings and in -Paramecium by Stevenson Smith are easily forgotten learnings or long -retained excitabilities. Sooner or later clear learning appears, and -then, from crabs to fish and turtle, from these to various birds and -mammals, from these to monkeys, and from these to man, a fairly certain -increase in sheer ability to learn, in the potency of a supposedly -constant degree of satisfyingness or annoyingness to influence the -connection preceding it, can be assumed. We cannot, of course, define -just what we mean by equal satisfyingness to a mouse and a man, but the -argument is substantially the same as that whereby we assume that the -gifted boy has more sheer ability to learn than the idiot, so that if -the two made the same response to the same situation and were equally -satisfied thereby, the former would form the habit more firmly. - -We may, therefore, expect that when knowledge of the structure and -behavior of the neurones comprising the connection-systems of animals (or -of the neurones’ predecessors in this function) progresses far enough -to inform us of just what happens when a connection is made stronger or -weaker and of just what effects satisfying and annoying states of affairs -exert upon the connection-system (and in particular upon the connections -most recently in activity) the ability to learn will show as true an -evolution as the ability to sneeze, oppose the thumb, or clasp an object -touched by the hand. - -If my analysis is true, the evolution of behavior is a rather simple -matter. Formally the crab, fish, turtle, dog, cat, monkey and baby have -very similar intellects and characters. All are systems of connections -subject to change by the law of exercise and effect. The differences -are: first, in the concrete particular connections, in _what_ stimulates -the animal to response, _what_ responses it makes, _which_ stimulus -connects with _which_ response, and second, in the degree of ability to -learn—in the amount of influence of a given degree of satisfyingness or -annoyingness upon the connection that produced it. - -The peculiarly human features of intellect and character, responses to -elements and symbols, are the results of: first, a receiving system that -is easily stimulated by the external world bit by bit (as by focalized -vision and touch with the moving hand) as well as in totals composed -of various aggregates of these bits; second, of an action-system of -great versatility (as in facial expression, articulation, and the -hands’ movements); and third, of a connection-system that includes the -connections roughly denoted by babbling, manipulation, curiosity, and -satisfaction at activity, bodily or mental, for its own sake; that is -capable of working in great detail, singling out elements of situations -and parts of responses; and that allows satisfying and annoying states of -affairs to exert great influence on their antecedent connections. Because -he learns fast and learns much, in the animal way, man seems to learn by -intuitions of his own. - - - - -CHAPTER VII - -THE EVOLUTION OF THE HUMAN INTELLECT[46] - - -To the intelligent man with an interest in human nature it must often -appear strange that so much of the energy of the scientific world has -been spent on the study of the body and so little on the study of the -mind. ‘The greatest thing in man is mind,’ he might say, ‘yet the least -studied.’ Especially remarkable seems the rarity of efforts to trace the -evolution of the human intellect from that of the lower animals. Since -Darwin’s discovery, the beasts of the field, the fowl of the air and -the fish of the sea have been examined with infinite pains by hundreds -of workers in the effort to trace our physical genealogy, and with -consummate success; yet few and far between have been the efforts to find -the origins of intellect and trace its progress up to human faculty. And -none of them has achieved any secure success. - -It may be premature to try again, but a somewhat extended series of -studies of the intelligent behavior of fishes, reptiles, birds and -mammals, including the monkeys, which it has been my lot to carry out -during the last five years, has brought results which seem to throw light -on the problem and to suggest its solution. - -Experiments have been made on fishes, reptiles, birds and various -mammals, notably dogs, cats, mice and monkeys, to see how they learned -to do certain simple things in order to get food. All these animals -manifest fundamentally the same sort of intellectual life. Their learning -is after the same general type. What that type is can be seen best from -a concrete instance. A monkey was kept in a large cage. Into the cage -was put a box, the door of which was held closed by a wire fastened to -a nail which was inserted in a hole in the top of the box. If the nail -was pulled up out of the hole, the door could be pulled open. In this -box was a piece of banana. The monkey, attracted by the new object, -came down from the top of the cage and fussed over the box. He pulled -at the wire, at the door, and at the bars in the front of the box. He -pushed the box about and tipped it up and down. He played with the nail -and finally pulled it out. When he happened to pull the door again, of -course it opened. He reached in and got the food inside. It had taken -him 36 minutes to get in. Another piece of food being put in and the -door closed, the occurrences of the first trial were repeated, but there -was less of the profitless pulling and tipping. He got in this time in -2 minutes and 20 seconds. With repeated trials the animal finally came -to drop entirely the profitless acts and to take the nail out and open -the door as soon as the box was put in his cage. He had, we should say, -learned to get in. - -The process involved in the learning was evidently a process of -selection. The animal is confronted by a state of affairs or, as we may -call it, a ‘situation.’ He reacts in the way that he is moved by his -innate nature or previous training to do, by a number of acts. These -acts include the particular act that is appropriate and he succeeds. In -later trials the impulse to this one act is more and more stamped in, -this one act is more and more associated with that situation, is selected -from amongst the others by reason of the pleasure it brings the animal. -The profitless acts are stamped out; the impulses to perform them in -that situation are weakened by reason of the positive discomfort or the -absence of pleasure resulting from them. So the animal finally performs -in that situation only the fitting act. - -Here we have the simplest and at the same time the most widespread sort -of intellect or learning in the world. There is no reasoning, no process -of inference or comparison; there is no thinking about things, no putting -two and two together; there are no ideas—the animal does not think of -the box or of the food or of the act he is to perform. He simply comes -after the learning to feel like doing a certain thing under certain -circumstances which before the learning he did not feel like doing. Human -beings are accustomed to think of intellect as the power of having and -controlling ideas and of ability to learn as synonymous with ability to -have ideas. But learning by having ideas is really one of the rare and -isolated events in nature. There may be a few scattered ideas possessed -by the higher animals, but the common form of intelligence with them, -their habitual method of learning, is not by the acquisition of ideas, -but by the selection of impulses. - -Indeed this same type of learning is found in man. When we learn to drive -a golf ball or play tennis or billiards, when we learn to tell the price -of tea by tasting it or to strike a certain note exactly with the voice, -we do not learn in the main by virtue of any ideas that are explained -to us, by any inferences that we reason out. We learn by the gradual -selection of the appropriate act or judgment, by its association with the -circumstances or situation requiring it, in just the way that the animals -do. - -From the lowest animals of which we can affirm intelligence up to man -this type of intellect is found. With it there are in the mammals obscure -traces of the ideas which come in the mental life of man to outweigh -and hide it. But it is the basal fact. As we follow the development of -animals in time, we find the capacity to select impulses growing. We find -the associations thus made between situation and act growing in number, -being formed more quickly, lasting longer and becoming more complex -and more delicate. The fish can learn to go to certain places, to take -certain paths, to bite at certain things and refuse others, but not much -more. It is an arduous proceeding for him to learn to get out of a small -pen by swimming up through a hole in a screen. The monkey can learn to do -all sorts of things. It is a comparatively short and easy task for him -to learn to get into a box by unhooking a hook, pushing a bar around and -pulling out a plug. He learns quickly to climb down to a certain place -when he sees a letter T on a card and to stay still when he sees a K. He -performs the proper acts nearly as well after 50 days as he did when they -were fresh in his mind. - -This growth in the number, speed of formation, permanence, delicacy and -complexity of associations possible for an animal reaches its acme in the -case of man. Even if we leave out of question the power of reasoning, -the possession of a multitude of ideas and abstractions and the power of -control over impulses, purposive action, man is still the intellectual -leader of the animal kingdom by virtue of the superior development -in him of the power of forming associations between situations or -sense-impressions and acts, by virtue of the degree to which the mere -learning by selection possessed by all intelligent animals has advanced. -In man the type of intellect common to the animal kingdom finds its -fullest development, and with it is combined the hitherto nonexistent -power of thinking about things and rationally directing action in accord -with thought. - -Indeed it may be that this very reason, self-consciousness and -self-control which seem to sever human intellect so sharply from that -of all other animals are really but secondary results of the tremendous -increase in the number, delicacy and complexity of associations which the -human animal can form. It may be that the evolution of intellect has no -breaks, that its progress is continuous from its first appearance to its -present condition in adult civilized human beings. If we could prove that -what we call ideational life and reasoning were not new and unexplainable -species of intellectual life but only the natural consequences of an -increase in the number, delicacy, and complexity of associations of -the general animal sort, we should have made out an evolution of mind -comparable to the evolution of living forms. - -In 1890 William James wrote, “The more sincerely one seeks to trace the -actual course of psychogenesis, the steps by which as a race we may have -come by the peculiar mental attributes which we possess, the more clearly -one perceives ‘the slowly gathering twilight close in utter dark.’” Can -we perhaps prove him a false prophet? Let us first see if there be any -evidence that makes it probable that in some way or another the mere -extension of the animal type of intellect has produced the human sort. If -we do, let us proceed to seek a possible account of _how_ this might have -happened, and finally to examine any evidence that shows this possible -‘how’ to have been the real way in which human reason has evolved. - -It has already been shown that in the animal kingdom there is, as we -pass from the early vertebrates down to man, a progress in the evolution -of the general associative process which practically equals animal -intellect, that this progress continues as we pass from the monkeys to -man. Such a progress is a real fact; it does exist as a possible _vera -causa_; it is thus at all events better than some imaginary cause of the -origin of human intellect, the very existence of which is in doubt. In a -similar manner we know that the neurones, which compose the brain and the -connections between which are the physiological parallels of the habits -that animals form, show, as we pass down through the vertebrate series, -an evolution along lines of increased delicacy and complexity. That an -animal associates a certain act with a certain felt situation means that -he forms or strengthens connections between certain cells. The increase -in number, delicacy and complexity of cell structures is thus the basis -for an increase in the number, delicacy and complexity of associations. -Now the evolution noted in cell structures affects man as well as the -other vertebrates. He stands at the head of the scale in that respect as -well. May not this obvious supremacy in the animal type of intellect and -in the adaption of his brain to it be at the bottom of his supremacy in -being the sole possessor of reasoning? - -This question becomes more pressing if we realize that we must have some -sort of brain correlate for ideational life and reasoning. Some sort of -difference in processes in the brain must be at the basis of the mental -differences between man and the lower animals, we should all admit. And -it would seem wise to look for that difference amongst differences which -really do or at least may exist. Now the most likely brain difference -between man and the lower animals for our purpose, to my mind indeed the -only likely one, is just this difference in the fineness of organization -of the cell structures. If we could show with any degree of probability -how it might account for the presence of ideas and of reasoning, we -should at least have the satisfaction of dealing with a cause actually -known to exist. - -The next important fact is that the intellect of the infant six months -to a year old is of the animal sort, that ideational and reasoning -life are not present in his case, that the only obvious intellectual -difference between him and a monkey is in the quantity and quality of -the associations formed. In the evolution of the infant’s mind to its -adult condition we have the actual transition within an individual from -the animal to the human type of intellect. If we look at the infant and -ask what is in him to make in the future a thinker and reasoner, we must -answer either by invoking some mysterious capacity, the presence of which -we cannot demonstrate, or by taking the difference we actually do find. -That is the difference in the quality and quantity of associations of the -animal sort. Even if we could never see how it came to cause the future -intellectual life, it would seem wiser to believe that it did than to -resort to faith in mysteries. Surely there is enough evidence to make it -worth while to ask our second question, “How might this difference cause -the life of ideas and reasoning?” - -To answer this question fully would involve a most intricate treatment of -the whole intellectual life of man, a treatment which cannot be attempted -without reliance on technical terms and psychological formulas. A fairly -comprehensible account of the general features of such an answer can, -however, be given. The essential thing about the thinking of the animals -is that they feel things in gross. The kitten who learned to respond -differently to the signals, “I must feed those cats” and “I will not -feed them,” felt each signal as a vague total, including the tone, the -movements of my head, etc. It did not have an idea of the sound of _I_, -another of the sound of _must_, another of the sound _feed_, etc. It did -not turn the complex impression into a set of elements, but felt it, as I -have said, in gross. The dog that learned to get out of a box by pulling -a loop of wire did not feel the parts of the box separately, the bolt as -a definite circle of a certain size, did not feel his act as a sum of -certain particular movements. The monkey who learned to know the letter -K from the letter Y did not feel the separate lines of the letter, have -definite ideas of the parts. He just felt one way when he saw one total -impression and another way when he saw another. - -Strictly human thinking, on the contrary, has as its essential -characteristic the breaking up of gross total situations into feelings -of particular facts. When in the presence of ten jumping tigers we not -only feel like running, but also feel the number of tigers, their color, -their size, etc. When, instead of merely associating some act with some -situation in the animal way, we think the situation out, we have a set -of particular feelings of its elements. In some cases, it is true, we -remain restricted to the animal sort of feelings. The sense impressions -of suffocation, of the feeling of a new style of clothes, of the pressure -of 10 feet of water above us, of malaise, of nausea and such like remain -for most of us vague total feelings to which we react and which we feel -most acutely but which do not take the form of definite ideas that we can -isolate or combine or compare. Such feelings we say are not parts of our -real intellectual life. They _are_ parts of our intellectual life if we -mean by it the mental life concerned in learning, but they are not if we -mean by it the life of reasoning. - -Can we now see how the vague gross feelings of the animal sort might turn -into the well-defined particular ideas of the human sort, by the aid of a -multitude of delicate associations? - -It seems to be a general law of mind that any mental element which occurs -with a number of different mental elements, appears, that is, in a number -of different combinations, tends to thereby acquire an independent life -of its own. We show children six lines, six dots, six peas, six pieces -of paper, etc., and thus create the definite feeling of sixness. Out of -the gross feelings of a certain number of lines, of dots, etc., we evolve -the definite elementary feeling of sixness by making the ‘six’ aspect of -the situations appear in a number of different connections. We learn to -feel whiteness as a definite idea by seeing white paper, white cloth, -white eggs, white plates, etc. We learn to feel the meaning of _but_ or -_in_ or _notwithstanding_ by feeling the meanings of many total phrases -containing each of them. Now in this general law by which different -associates for the same elementary process elevate it out of its position -as an undifferentiated fragment of a gross total feeling, we have, I -think, the manner in which the vague feelings of the nine-months-old -infant become the definite ideas of the five-year-old boy, the manner in -which in the race the animal mind has evolved into the human, and the -explanation of the service performed by the increase in the delicacy of -structure of the human brain and the consequent increase in the number of -associations. - -The bottle to the six-months-old infant is a vague sense-impression which -the infant does not think about or indeed in the common meanings of the -words perceive or remember or imagine. Its presence does not arouse -ideas, but action. It is not to him a thing so big, or so shaped, or so -heavy, but is just a vaguely sizable thing to be reached for, grabbed and -sucked. Like the lower animals, with the exception that as he grows a -little older he reacts in very many more ways, the child feels things in -gross in a way to lead to direct reactions. Vague sense-impressions and -impulses make up his mental life. The bottle, which to a dog would be a -thing to smell at and paw, to a kitten a thing to smell at and perhaps -worry, is to the child a little later a thing to grab and suck and turn -over and drop and pick up and pull at and finger and rub against its toes -and so on. The sight of the bottle thus becomes associated with many -different reactions, and thus by our general law tends to gain a position -independent of any of them, to evolve from the condition of being a -portion of the cycles see-grab, see-drop, see-turn over, etc., to the -condition of being a definite idea. - -The increased delicacy and complexity of the cell structures in the human -brain give the possibility of very small parts of the brain-processes -forming different connections, allow the brain to work in very great -detail, provide processes ready to be turned into definite ideas. The -great number of associations which the human being forms furnish the -means by which this last event is consummated. The infant’s vague -feelings of total situations are by virtue of the detailed working of -his brain all ready to split up into parts, and his general activity and -curiosity provide the multitude of different connections which allow them -to do so. The dog, on the other hand, has few or no ideas because his -brain acts in coarse fashion and because there are few connections with -each single process. - -When once the mind begins to function by having definite ideas, all the -phenomena of reasoning soon appear. The transition from one idea to -another is the feeling of their relationship, of similarity or difference -or whatever it may be. As soon as we find any words or other symbols to -express such a feeling, or to express our idea of an action or condition, -we have explicit judgments. Observation of any child will show us that -the mind cannot rest in a condition where it has a large body of ideas -without comparing them and thinking about them. The ideas carry within -them the forces that make abstractions, feelings of similarity, judgments -and other characteristics of reasoning. - -In children two and three years of age we find all these elements of -reasoning present and functioning. The product of children’s reasoning -is often irrational, but the processes are all there. The following -instances from a collection of children’s sayings by Mr. H. W. Brown show -children making inductions and deductions after the same general fashion -as adults:— - - (2 yrs.) T. pulled the hairs on his father’s wrist. Father. - “Don’t, T., you hurt papa!” T. “It didn’t hurt grandpa.” - - (2 yrs. 5 mos.) M. said, “Gracie can’t walk, she wears little - bits of shoes; if she had mine, she could walk. When I get some - new ones, I’m going to give her these, so she can walk.” - - (2 yrs. 9 mos.) He usually has a nap in the forenoon, but - Friday he did not seem sleepy, so his mother did not put him - to bed. Before long he began to say, “Bolly’s sleepy; mamma - put him in the crib!” This he said very pleasantly at first; - but, as she paid no attention to him, he said, “Bolly cry, then - mamma will.” And he sat down on the floor and roared. - - (3 yrs.) It was between five and six in the afternoon; the - mother was getting the baby asleep. J. had no one to play with. - He kept saying, “I wish R. would come home; mamma, put baby - to bed, so R. will come home.” I usually get home about six, - and as the baby is put to bed about half-past five, he had - associated the one with the other. - - (3 yrs.) W. likes to play with oil paints. Two days ago my - father told W. he must not touch the paints any more, for he - was too small. This morning W. said, “When my papa is a very - old man, and when I am a big man and don’t need any papa, then - I can paint, can’t I, mamma?” - - (3 yrs.) G.’s aunt gave him ten cents. G. went out, but soon - came back saying, “Mamma, we will be rich now.” “Why so, G.?” - “Because I planted my ten cents, and we will have lots of ten - cents growing.” - - (3 yrs.) B. climbed up into a large express wagon, and would - not get out. I helped him out, and it was not a minute before - he was back in the wagon. I said, “B., how are you going to get - out of there now?” He replied, “I can stay here till it gets - little, and then I can get out my own self.” - - (3 yrs.) F. is not allowed to go to the table to eat unless she - has her face and hands washed and her hair combed. The other - day she went to a lady visiting at her house and said, “Please - wash my face and hands and comb my hair; I am very hungry.” - - (3 yrs.) If C. is told not to touch a certain thing, that it - will bite him, he always asks if it has a mouth. The other day - he was examining a plant, to see if it had a mouth. He was told - not to break it, and he said, “Oh, it won’t bite, because I - can’t find any mouth.” - -Nowhere in the animal kingdom do we find the psychological elements of -reasoning save where there is a mental life made up of the definite -feelings which I have called ‘ideas,’ but they spring up like magic -as soon as we get in a child a body of such ideas. If we have traced -satisfactorily the evolution of a life of ideas from the animal life of -vague sense-impressions and impulses, we may be reasonably sure that no -difficulty awaits us in following the life of ideas in its course from -the chaotic dream of early childhood to the logical world-view of the -adult scientist. - -In a very short time we have come a long way, from the simple learning of -the minnow or chick to the science and logic of man. The general frame -of mind which one acquires from the study of animal behavior and of the -mental development of young children makes our hypothesis seem vital and -probable. If the facts did eventually corroborate it, we should have an -eminently simple genesis of human faculty, for we could put together the -gist of our contention in a few words. We should say:— - -“The function of intellect is to provide a means of modifying our -reactions to the circumstances of life, so that we may secure pleasure, -the symptom of welfare. Its general law is that when in a certain -situation an animal acts so that pleasure results, that act is selected -from all those performed and associated with that situation, so that, -when the situation recurs, the act will be more likely to follow than -it was before; that on the contrary the acts which, when performed in a -certain situation, have brought discomfort, tend to be dissociated from -that situation. The intellectual evolution of the race consists in an -increase in the number, delicacy, complexity, permanence and speed of -formation of such associations. In man this increase reaches such a point -that an apparently new type of mind results, which conceals the real -continuity of the process. This mental evolution parallels the evolution -of the cell structures of the brain from few and simple and gross to many -and complex and delicate.” - -Nowhere more truly than in his mental capacities is man a part of nature. -His instincts, that is, his inborn tendencies to feel and act in certain -ways, show throughout marks of kinship with the lower animals, especially -with our nearest relatives physically, the monkeys. His sense-powers -show no new creation. His intellect we have seen to be a simple though -extended variation from the general animal sort. This again is presaged -by the similar variation in the case of the monkeys. Amongst the minds of -animals that of man leads, not as a demigod from another planet, but as a -king from the same race. - - - - -FOOTNOTES - - -[1] ‘Animal Intelligence: An Experimental Study of the Associative -Processes in Animals’ (’98), ‘The Instinctive Reactions of Young Chicks’ -(’99), ‘A Note on the Psychology of Fishes’ (’99), and ‘The Mental Life -of the Monkeys’ (’01). I have added a theoretical paper, ‘The Evolution -of the Human Intellect,’ which appeared in the _Popular Science Monthly_ -in 1901, and which was a direct outgrowth of the experimental work. I am -indebted to the management of the _Psychological Review_, and that of the -_American Naturalist_ and _Popular Science Monthly_, for permission to -reprint the three shorter papers. - -[2] Unless one assumes telepathic influences. - -[3] Reason in Common Sense, p. 154 ff. - -[4] This chapter originally appeared as Monograph Supplement No. 8 of the -Psychological Review. - -[5] I do not mean that scientists have been too credulous with regard -to spiritualism, but am referring to the cases where ten or twenty -scientists have been sent to observe some trick-performance by a -spiritualistic ‘medium,’ and have all been absolutely confident that they -understood the secret of its performance, _each of them giving a totally -different explanation_. - -[6] The phrase ‘practically utter hunger’ has given rise to -misunderstandings. I have been accused of experimenting with starving or -half-starved animals, with animals brought to a state of fear and panic -by hunger, and the like! - -The desideratum is, of course, to have the motive as nearly as possible -of equal strength in each experiment with any one animal with any one -act. That is, the animal should be as hungry at the tenth or twentieth -trial as at the first. To attain this, the animal was given after each -‘success’ only a very small bit of food as a reward (say, for a young -cat, one quarter of a cubic centimeter of fish or meat) and tested not -too many times on any one day. ‘Utter hunger’ means that no diminution in -his appetite was noted and that at the close of the experiment for the -day he would still eat a hearty meal. After the experiments for the day -were done, the cats received abundant food to maintain health, growth and -spirits, but commonly somewhat less than they would of their own accord -have taken. No one of the many visitors to the room mentioned anything -extraordinary or distressful in the animals’ condition. There were no -signs of fear or panic. - -Possibly I was wrong in choosing the term ‘utter hunger’ to denote the -hunger of an animal in good, but not pampered, condition and without food -for fourteen hours. It is not sure, however, that the term ‘utter hunger’ -is inappropriate. The few reports made of experiments in going without -food seem to show that, in health, the feeling of hunger reaches its -maximum intensity very early. It is of course not at all the same thing -as the complex of discomforts produced by long-continued insufficiency of -food. Hunger is not at all a synonym for starvation. - -[7] The experiments now to be described were for the most part made in -the Psychological Laboratory of Columbia University during the year -’97-’98, but a few of them were made in connection with a general -preliminary investigation of animal psychology undertaken at Harvard -University in the previous year. - -[8] No. 7 hit the string in his general struggling, apparently utterly -without design. He did not realize that the door was open till, two -seconds after it had fallen, he happened to look that way. - -[9] No. 6, in trying to crawl out at the top of the box, put its paw in -above the string. It fell down and thus pulled the string. It did not -claw at it, and it was 16 seconds before it noticed that the door was -open. In all the other times that it escaped the movement was made in the -course of promiscuous scrambling, never in anything like the same way -that No. 2 made it. - -[10] No. 3 did not go out until 12 seconds had elapsed after it had -pulled the string. - -[11] The back of the pen adjoined the elevator shaft, being separated -from it by a partition 33 inches high. No. 2 heard the elevator coming up -and put his paws up on the top of this partition so as to look over. In -so doing he knocked the fastening of the cord at that end and opened the -door. He did not turn to come out, and I shut the door again. - -[12] FF was a box 40 × 21 × 24 inches, the door of which could be opened -by putting the paw out between the bars to its right and pulling a loop -which hung 16 inches above the floor, 4 inches out from the box and 6 -inches to the right of the door. - -[13] KKK was box K with both bolts removed. All that had to be done was -to poke the paw out at one side of the door and press down a little bar -of wood. - -[14] The cats and chick were left in for two minutes at each trial, the -dogs for from one to one and a half minutes. - -[15] One result of the application of experimental method to the study of -the intellect of animals was the distinction of learning by the selection -of impulses or acts from learning by the selection of ideas. The usual -method of learning in the case of animals other than man was shown by -the studies reprinted in this volume to be the direct selection, in a -certain situation, of a desirable response and its association with that -situation, not the indirect selection of such a response by the selection -of some _idea_ which then of itself produced the response. The animals -did not usually behave as if they _thought of_ getting freedom or food -in a certain way and were thereby moved to do so, but as if the stimulus -in question made immediate connection with the response itself or an -intimately associated impulse. - -The experiments had in this respect both a negative or destructive and -a positive or constructive meaning. On the one hand, they showed that -animal learning was not homologous with human association of ideas; that -animal learning was not human learning _minus_ abstract and conceptual -thought, but was on a still ‘lower’ level. On the other hand, the first -positive evidence that animals could, under certain circumstances, learn, -as man so commonly does, by the indirect connection of a response with a -situation through some non-sensory relic or representative of the latter, -came from my experiments. - -It was perhaps natural that the more exciting denial of habitual learning -by ideas should have attracted more attention than the somewhat tedious -experiments to prove that under certain conditions they could so learn. -At all events, a perverse tradition seems to have grown up to the effect -that I denied the possibility of animals having images or learning in any -case by representative thinking. - -There is some excuse for this tradition in the fact that whereas the -proof that the habitual learning of these dogs and cats did not require -‘ideas’ is clear and emphatic, my evidence that certain features of their -behavior _did_ require ‘ideas’ is complicated and imperfect. - -The fact seems to be that a ‘free idea’ comes in the animals or in -man only as a result of a somewhat elaborate process of analysis or -extraction from a gross total sensory process. The primary level or grade -of experience, common to animals and little babies, comprises states -of mind such as an adult man gets if lost in anger, fear, suffocation, -dyspepsia, looking at a panorama of unknown objects with head upside -down, smelling the mixture of odors of a soap factory, driving a golf -ball, dashing to the net in a game of tennis, warding off a blow, or -swimming under water. For a man to get a distinct controllable percept of -approaching asthma, of a carpet loom seen upside down, or of a successful -‘carry through,’ or ‘smash’ or ‘lob,’ so that one knows just what one is -experiencing or doing, and can recall just what one experienced or did, -requires further experience of the element in question—contemplation of -it in isolation or dealings with it in many varied connections. So for -a cat to get a distinct controllable percept of a loop, or of its own -clawing or nosing or pulling, it must have the capacity to analyze such -elements out of the total gross complexes in which they inhere, and also -certain means or stimuli to such analysis. - -This capacity or tendency the cats and dogs do, in my opinion, possess, -though in a far less degree than the average child. They also suffer from -lack of stimuli to the exercise of the capacity. Their confinement, for -the most part, to the direct sensory experience of things and acts, is -due in part to the weakness of the capacity or tendency of their neurones -to act in great detail, and in part to the lack of such stimuli as visual -exploration of things in detail, manual manipulation of the same thing -in many ways, and the identification of elements of objects and acts by -language. They get few free ideas because they are less ready than man to -get them under the same conditions and because their instinctive behavior -and social environment offer conditions that are less favorable. The task -of getting an animal to have some free ideational representative of a red -loop or of pushing up a button with the nose may be compared with that -of getting a very stupid boy to have a free ideational representative of -acceleration, or of the act of sounding _th_. The difference between them -and man which is so emphasized in the text, though real and of enormous -practical importance, is thus not at all a mysterious gap or trackless -desert. We can see our way from animal to human learning. - -[16] A man may learn to swim from the general feeling, “I want to be -able to swim.” While learning, he may think of this desire, of the -difficulties of the motion, of the instruction given him, or of anything -which may turn up in his mind. This is all extraneous and is not -concerned in the acquisition of the association. Nothing like it, of -course, goes on in the animal’s mind. Imagine a man thrown into the water -repeatedly, and gradually floundering to the shore in better and better -style until finally, when thrown in, he swims off perfectly, and deprive -the man of all extraneous feelings, and you have an approximate homologue -of the process in animals. He feels discomfort, certain impulses to -flounder around, some of which are the right ones to move his body to -the shore. The pleasure which follows stamps in these, and gradually the -proper movements are made immediately on feeling the sense-impression of -surrounding water. - -[17] See 10 in A, 3 in A, 10 in D; 10 in C, 4 in C, 3 in C; 6, 2, 5, 4 in -E; 4 in F; 10 in H, 3 in H; 3, 4, 5, in I; 4 in G, 3 in G; 3 in K; 10 in -L; dog 1 in N and CC; dog 1 in G and O. - -[18] This chapter appeared originally in the _Psychological Review_, Vol. -VI, No. 3. - -[19] This double rating is necessary because of the fact that the chick -often gives several distinct pecks in a single reaction. The ‘times -reacted to’ mean the number of different times that the chicks noticed -the color. - -[20] The crude experiments reported in this and the preceding paragraphs -were not made to test the presence of color vision proper, that is, -of differentiation of two colors of the same brightness, but only to -ascertain how chicks reacted to ordinary colored objects. It was, -however, almost certain from the relative frequency of the reactions that -the intensity factor was not the cause of the response. For example, if -it had been, black on white and yellow on black should have been pecked -at oftener. - -[21] This chapter appeared originally in the _American Naturalist_, Vol. -XXXIII, No. 396. - -[22] This chapter appeared originally as Monograph Supplement No. 15 to -the _Psychological Review_. - -[23] Pp. 20 to 155 of this volume. - -[24] _American Journal of Psychology_, Vol. X, pp. 256-279; Vol. XI, pp. -80-100, 131-165; Vol. XII, pp. 206-239. - -[25] Practically a memory trial of CC, done January 21, 1900. - -[26] Did it by pulling door and thus shaking lever. - -[27] Practically a memory trial of SS. - -[28] Did it by pulling door and biting wire. - -[29] This, I regret, was not done [E. L. T., 1911]. - -[30] The acts and the number of chances to see me do each and the results -were as follows; details can be found on the table on page 226. F = -failed after tuition. - - No. 1.—MM 21 F - Theta 5 F - QQ 10 F - RR 4 F - W 9 did in .22 - Delta 15 F - Epsilon 40 F - QQ (f) 15 F - QQ (c) 1 did in 2.20 - - No. 3.—Theta 25 did in 3.00. - QQ 40 F - Gamma 30 F - Epsilon 25 F - QQ (ff) 5 F - QQ (c) 20 F, did in 1.30, F, 5 F, 5 F - QQ (e) 5 F, did in 2.00 - -[31] He did push it once with his nose. - -[32] I inadvertently pulled the nail out in one of five cases when I was -fingering it to see if attracting his attention to it would lead to the -act. - -[33] Not significant. Due to inattention. Was temporary. - -[34] Pulled wire and door. - -[35] Pushed with head by chance. - -[36] Reached in at 9:30 and took out the banana, which I replaced. - -[37] Did by constant pulling at the door. - -[38] Did touch nail four times. - -[39] Did by pulling hard on wire (not loop); the loop got loose from nail. - -[40] Did by pulling at the door till the bar was worked around. - -[41] The ‘say,’ may be replaced by some bodily attitude, facial -expression, or other verbal formula that identifies the situation as one -to be responded to by speech. - -[42] This would, of course, result from a well-known corollary of the -laws of habit. - -[43] In _Essays Philosophical and Psychological in Honor of William -James_, pp. 591-599. - -[44] Professor Smith’s own experiments illustrate this. - -[45] Biological Lectures from the Marine Biological Laboratory of Woods -Holl, 1898, p. 323 ff. - -[46] This chapter appeared originally in the _Popular Science Monthly_, -Nov., 1901. - - - - -INDEX - - - Abstraction, 120. - _See also_ Reasoning. - - Action-system, importance of the study of the, 15 f.; - of monkeys, 190 f., 237. - - Anecdotal school in animal psychology, 23 ff., 151 f. - - Apparatus, descriptions of, 29 ff., 56 ff., 61 f., 169 f., 177 ff., - 196 ff. - - Assimilation, 249 f. - - Association, as a problem in animal psychology, 20 ff.; - by similarity, 116 ff.; - complexity of, 132 ff.; - conditions of, 43 ff.; - delicacy of, 128 ff., 195 ff.; - development of, in the animal kingdom, 285 ff.; - in cats, 38 ff.; - in chicks, 63 f.; - in dogs, 56 ff.; - in fishes, 169 ff.; - in man, 123 ff., 127, 285; - in monkeys, 182 ff., 194 f., 209 ff.; - in relation to attention, 44 ff.; - to individual differences, 52 ff.; - to inhibition, 142 ff.; - to instincts, 36 f., 142 ff.; - to previous experience, 48 ff.; - number of connections formed by, 135 ff.; - permanence of connections formed by, 138 ff., 194 f., 203 f.; - progress of, measurable by time-curves, 28, 40, 42; - the mental fact in, 98 ff.; - without ideas, 101 f., 127, 209 ff. - _See also_ Associations and Learning. - - Associations, complexity, 132 ff.; - delicacy, 128 ff., 195 ff.; - number, 121, 135 ff.; - permanence, 138 ff., 194 f., 203 f. - - Associative memory. _See_ Association. - - Attention, 144 ff.; - and association, 44 ff.; - to imposed movements, 103 ff. - - - Behavior, acquired tendencies to, 244 ff. (_see also_ Association); - evolution of, 272 ff.; - general laws of, 241 ff.; - indefiniteness of the term, 5; - of cats, 35 ff., 88 f., and _passim_; - of chicks, 63 f., 138, 143 f., 156 ff., and _passim_; - of dogs, 59 ff., 92 ff.; - of fishes, 169 ff.; - of monkeys, 182 ff.; - original tendencies to, 242 f. (_see also_ Instincts); - predictability of, 241 f.; - proposed simplification of the laws of, 265 ff.; - _versus_ consciousness as an object of study, 1 ff. - _See also_ Association, Instincts, Learning, Memory, etc. - - BOSWORTH, F. D., 240. - - - Cats, associative processes in, 35 ff.; - imitation in, 85 ff.; - the presence of ideas in, 100 ff.; - reasoning in, 67 ff. - - Chicks, associative processes in, 61 ff.; - imitation in, 81 ff.; - instincts of, 156 ff. - - Complexity, of associations, 132 ff. - - Concepts, 116 ff. - - Connection-systems, action of, in association, 246 ff., 266; - importance of the study of, 16 f. - - Consciousness, amenability of, to scientific study, 7 ff.; - as pure experience, 13 f.; - as studied by the one who has or is it, 10 ff.; - of animals, 25 f., 67 ff., 98 ff., 123, 146 f., and _passim_; - social, 146 f.; - space-relations of, 14; - _versus_ behavior as an object of study, 1 ff. - - Coördinations, of chicks, 160 ff. - - - DEAN, B., 161. - - Delicacy of association, 128 ff., 195 ff. - - DEWEY, J., 6. - - Differences, between species of animals in the associative processes, - 64 ff. - - Discomfort, as an influence in learning, 245 ff. - - Discrimination, in cats and dogs, 128 ff.; - in chicks, 156 ff.; - in monkeys, 195 ff. - - Dogs, associative processes in, 56 ff.; - imitation in, 91 ff.; - the presence of ideas in, 115 f.; - reasoning in, 67 ff. - - - Education, applications of animal psychology in, 149 f. - - Effect, the law of, 244 f., 266 ff. - - Emotional reactions of chicks, 162 ff. - - Evolution, of behavior, 272 ff.; - of human intellect, 282 ff.; - of ideas, 289 ff. - - Exercise, the law of, 244 f. - - Experience, the influence of previous, 48 ff. - - Experiments, need of, in animal psychology, 26; - with cats, 35 ff., 85 ff., 103 ff., 111 f., 114 f., 129 ff., 138 f.; - with chicks, 61 ff., 81 ff., 132, 136, 143 f., 156 ff.; - with dogs, 56 ff., 91 ff., 103 ff., 115 f.; - with fishes, 169 ff.; - with monkeys, 176-235, _passim_. - - - Fears, of chicks, 162 ff. - - Fishes, experiments with, 169 ff. - - - GALTON, F., 3. - - - Habit. _See_ Association. - - HALL, G. S., 3. - - Human. _See_ Man. - - Hunger, effect of, on animal learning, 27 f. - - HUNT, H. E., 163. - - - Ideas, development of, 121 f., 289 ff.; - existence of, as adjuncts in animal learning, 108 ff., 189 ff., 206 - ff., 222 ff.; - impotence of, to create connections, 257 ff. - - Ideo-motor action, 257 ff. - - Images, 108 f. _See also_ Ideas. - - Imitation, analysis of the supposed effects of, 251 ff.; - in cats, 85 ff.; - in chicks, 81 ff.; - in dogs, 91 ff.; - in general, 76 ff., 94 ff.; - in monkeys, 96, 211 ff., 219 ff.; - in speech, 253 ff. - - Impulses, as features of the associative processes, 100 ff.; - defined, 37. - - Incubation, the instinct of, 276 ff. - - Individual differences in association, 52 ff. - - Inhibition of instincts by association, 142 ff. - - Instincts, as explanations of some cases of supposed imitation, 251; - inhibition of, 142 ff.; - of chicks, 156 ff.; - of incubation, 276 ff.; - of monkeys, 237; - the starting-point of animal learning, 36 f. - - Intellect. _See_ Association, Ideas, Imitation, Memory, Reasoning, - etc. - - Interaction, 147 f. - - Introspection, the over-emphasis of, 3. - - - JAMES, W., 3, 120, 143, 286. - - JENNINGS, H. S., 267, 268, 269, 270, 274, 279. - - - KLINE, L. W., 173. - - - Language, 253 ff. - - Learning, evolution of, 278 ff.; - methods of, 174 f. - _See_ Association, Behavior, Ideas, Imitation, Reasoning. - - LUBBOCK, J., 240. - - - Man, compared with lower animals in intellect, 123 ff., 239 f.; - mental evolution of, 282 ff. - - Memory, 108 f., 138 ff., 203. - _See_ Association and Permanence of associations. - - Methods in animal psychology, 22 ff. - - MILLS, W., 191. - - Monkeys, 172 ff.; - associative processes in, 182 ff.; - differences from lower mammals, 189 ff., 204 ff., 237 ff.; - general mental development of, 236 ff.; - imitation of man by, 211 ff.; - imitation of other monkeys by, 219 ff.; - possible mental degeneracy of, 151; - presence of ideas in, 189 ff., 206 ff., 222 ff.; - reasoning in, 184 ff. - - MORGAN, C. L., 3, 80, 99 f., 101, 119, 120, 125 f., 146, 147, 162, - 165 f. - - Motives, used in the experiments, 26 ff.; - defined, 38. - - - Number of associations, 135 ff.; - as a cause of the development of free ideas, 121 f. - - - PECKHAM, G. W. and E. G., 240. - - Pecking, accuracy of, in chicks, 159 f. - - Pedagogy, applications of animal psychology to, 149 f. - - Permanence of associations, 138 ff., 203. - - Predictability of behavior, 241 f. - - Primates. _See_ Monkeys. - - - Reasoning, 118 f.; - and free ideas, 291 ff.; - as a consequence of the laws of exercise and effect, 263 ff.; - in cats and dogs, 67 ff.; - in monkeys, 184 ff. - - Recepts, 120. - - Resolution, Jennings’ law of, 267 ff. - - Responses to situations as the general form of behavior, 242 ff., 283 - f. - - ROMANES, G. J., 68 f., 70, 80. - - - SANTAYANA, G., 6, 18 f. - - Satisfaction, the influence of, in learning, 147 f., 244 f.; - the nature of, 245 f. - - Situation and response as the general form of behavior, 242 ff., 283 - ff. - - SMALL, W. S., 173. - - SMITH, S., 269 f., 280. - - Social consciousness of animals, 146 f. - - SPALDING, D. A., 162, 163, 165. - - STOUT, G. F., 3. - - Swimming, by chicks, 161 f. - - - Time of achievement as a measure of the closeness of association, - 28, 40, 42, 54. - - Time-curves, 38 ff., 57 ff., 65, 185 f.; - as evidence against the existence of reasoning, 73 f. - - TITCHENER, E. B., 2. - - - Vigor, as a factor in learning, 46. - - - WHITMAN, C. O., 275 ff. - - - YERKES, R. M., 240. - - - - - -The following pages contain advertisements of Macmillan books on kindred -subjects - - - - -The Animal Behavior Series - -Under the General Editorship of ROBERT M. YERKES, Ph.D., Instructor in -Comparative Philosophy, Harvard University - -The aim of the Series is to present a number of small volumes which taken -together shall form a comprehensive introduction to Comparative Psychology - -_NOW READY_ - - -The Dancing Mouse - -By ROBERT M. YERKES, Ph.D. - - _Cloth, 12mo, xxi + 290 pages, illus., $1.25 net_ - -“Dr. Yerkes’ book is a most interesting example of modern laboratory -methods and can be read with profit by any one, on account of the -accurate methods of observation and careful deductive reasoning -which it shows. An elaborate, painstaking system of experiments was -carried on with over 400 mice, with the object of determining muscular -coördination, structural peculiarities, strength of the special sense -organs, habit formation, educability, and strength of memory of these -little animals. Some experiments were also undertaken along the line of -inherited peculiarities.... The work is really only a preliminary study, -but it will be read with much interest by all students of comparative -psychology.”—_Journal of American Medical Association._ - - -The Animal Mind - -By MARGARET FLOY WASHBURN, Ph.D., Professor of Philosophy, Vassar College - - _Cloth, 12mo, 333 pages, $1.60 net_ - -“As the author points out, the title of this book might more -appropriately have been ‘The Animal Mind Deduced from Experimental -Evidence,’ for the facts here set forth are very largely the results -of the experimental method in comparative psychology. The mass of -experimental material that has been accumulated from the researches of -physiologists and psychologists is already great, but is also for the -most part inaccessible to the ordinary student, being widely scattered -and to a considerable extent published in the journals of specialists, -which the average college library does not contain. Hence the usefulness -of the present ... interesting work.”—_New York Sun._ - - - The Series is Published by - THE MACMILLAN COMPANY - 64-66 Fifth Avenue, New York - - - - -OTHER NATURE BOOKS - - -Four-Footed Americans _And their Kin_ - -By MABEL OSGOOD WRIGHT. Edited by FRANK M. CHAPMAN. Illustrated by ERNEST -SETON THOMPSON - - _Cloth, 12mo, $1.50 net; School Library Edition, 50 cents net_ - -“It deserves commendation for its fascinating style, and for the fund of -information which it contains regarding the familiar and many unfamiliar -animals of this country. It is an ideal book for children, and doubtless -older folk will find in its pages much of interest.”—_The Dial._ - -“Books like this are cups of delight to wide-awake and inquisitive girls -and boys. Here is a gossipy history of American quadrupeds, bright, -entertaining, and thoroughly instructive. The text, by Mrs. Wright, has -all the fascination that distinguishes her other outdoor books.”—_The -Independent._ - - -Citizen Bird - -_Scenes from Bird Life in Plain English for a Beginner_ - -By MABEL O. WRIGHT and Dr. ELLIOTT COUES. Profusely Illustrated by LOUIS -AGASSIZ FUERTES - - _Cloth, 12mo, $1.50 net; School Library Edition, 50 cents net_ - -“When two writers of marked ability in both literature and natural -history unite to produce a work giving scope to their special talents, -the public has reason to expect a masterpiece of its kind. In the -‘Citizen Bird,’ by Mabel O. Wright and Dr. Elliott Coues, this -expectation is realized—seldom is the plan of a book so admirably -conceived, and in every detail so excellently fulfilled.”—_The Dial._ - -“There is no other book in existence so well fitted for arousing -and directing the interest that all children feel toward the -birds.”—_Tribune_, Chicago. - - -Flowers and Ferns _In their Haunts_ - -By MABEL OSGOOD WRIGHT - - _New Edition, cloth, 12mo, $2.00 net_ - -The subjects are treated in their relation to landscape—the whole bound -together with a thread of narrative. The book thus has the fascination -of romance, yet no better handbook could be found for the study of the -flowers in their natural surroundings. There are over 50 full-page plates -of the flowers where they live and grow, along the roadside, in wood or -by river. In addition to these plates, there are over 100 illustrations -in the text, made direct from photographs by the author and by J. H. -McFarland. - - -A Text-book on the Principles of Animal Histology - -By ULRIC DAHLGREN, M.S., Assistant Professor of Biology in Princeton -University; and WILLIAM A. KEPNER, A.B., Adjunct Professor of Biology in -the University of Virginia - - _Cloth, 515 pp., 8vo, $3.75 net_ - -“The name of the senior author alone leads us to expect much from this -volume, and the most careful scrutiny reveals almost no defects. It -easily takes first place among histologies, chiefly because of the -invaluable comparative element. With few exceptions, histologies, -intended as they have been primarily for the medical student, -have heretofore been based for the most part on the genus _Homo_. -Morphologists and anatomists will welcome a general histology which in -the widest sense holds to its title, treating its subject as a pure -science.... One can scarcely imagine a clearer or better arranged -text-book either for the general student or for the specialist in any of -the many related sciences. Since scientists in many fields often have -occasion to refer to or to verify some point in histology, the volume -will appeal to readers outside of the domain of histology proper.”—_New -York Evening Post._ - -“In marked contrast to practically all the text-books of histology in -the English language, which deal largely or exclusively with human -or mammalian structures, this new book discusses the tissues of all -classes of animals. It is therefore possible to treat the subject much -more broadly and satisfactorily than has hitherto been done.”—_American -Journal of Science._ - -“When one considers the narrow, technical training which students in -histology usually receive, whether they be medical students or not, one -cannot but wish that a course similar to that outlined in this book might -be given in every college and university.”—_Science._ - - -A Synoptic Text-book of Zoölogy for Colleges and Schools - -By ARTHUR WISSWALD WEYSSE, A.M., Ph.D. (Harvard), Instructor in Zoölogy -at the Massachusetts Institute of Technology, and Associate Professor of -Physiology at Boston University - - _Cloth, 545 pp., 8vo, $2.25 net_ - -“To relieve the tenseness of such a study as zoölogy, the author -deals—whenever practicable—with some facts of everyday interest, such as -the transmission of malaria by mosquitoes, the division of labor among -ants and bees, the storing of food for the young, and several others -of this character. These are pleasant little oases in the wilderness -of rigidly scientific terms and facts. Not only is the author to be -congratulated on the perseverance which made the volume possible, but -also are the publishers for the mechanical part they have played. The -book is entirely up to the high standard of the house that publishes it. -The illustrative element is most meritorious.”—_Journal of Education._ - -“A work of great value ... addressed to college students who do not -necessarily intend to become specialists, but approach the subject with -trained minds and with some knowledge of cognate sciences. We begin, -if not literally at the beginning, yet with the protoplasmic cell, but -pass almost immediately to the description of the various animal types -in which classification in minute subdivisions is not attempted. A third -part deals with the general principles of zoölogy. The book has been -specially adapted for use in connection with laboratory and field work, -as well as for systematic study.”—_Churchman._ - -“The text is noteworthy for its simplicity and clearness, and the choice -of subject-matter has been made with care. Considerable attention has -been paid to the introduction of illustrative data which bear on general -biological problems or are of economic or sanitary importance. The -book is also free from the more technical terminology which only the -specialist needs. The arrangement of the subject-matter is excellent. -After laying down a few general principles, the various animal types are -dealt with in detail, and the theoretical phases and general problems are -discussed in the closing section. The book forms a clearly presented, -well-balanced, comprehensive, and accurate epitome of zoölogy.”—_The -Dial._ - - -Experimental Zoölogy - -By THOMAS HUNT MORGAN, Professor of Experimental Zoölogy, Columbia -University - - _Cloth, 454 pp., 8vo, $2.75 net_ - -“The author long ago won his spurs in this field, through his unrivaled -researches in the phenomena of regeneration; and he has now proved -himself a master of compilation—selecting the most significant -experiments carried on in various countries, weighing them fairly, and -summing up with a conservatism which is perhaps the most valuable feature -of the book. The thoroughness and lucidity of the work make it serve -three distinct purposes: the intelligent layman without any previous -knowledge of the subject may read and appreciate any part of it; the -student of experimental zoölogy will find it a veritable vade mecum; and -the advanced scientist will be glad to refer to the generous summaries of -literature relating to each subject.”—_Nation._ - -“Professor Morgan has, however, done much sound and some brilliant work. -In his special field, the regrowth of amputated parts and the relation -of this property to the general theory of evolution, his experiments -have become classic, and he is himself one of the first authorities -in the world. His own eminence in the field, combined with a simple, -straightforward style, and a just and sympathetic appreciation of the -work of other men, even when their opinions are opposed to his own, -render him especially well fitted to sum up the general results of the -new science. This he has accomplished with marked success in the work -before us. He has succeeded in bringing together a large body of fact -without becoming dull; without being fatuously ‘popular,’ he has been -untechnical and clear.”—_Boston Transcript._ - - -The Protozoa - -By GARY N. CALKINS, Ph.D., Instructor in Zoölogy, Columbia University - - _Cloth, 347 pp., 8vo, $3.00 net_ - -“The author has not aimed at putting forward an exhaustive, severely -scientific treatise upon the group in question. His work may be described -rather as a simple and intelligible introduction to the study of the -Protozoa and of the many fascinating biological problems connected with, -or illustrated by, this subdivision of the animal kingdom, in such a way -as to awaken the interest of the beginner, no less than to strengthen the -hands of the expert.”—_Nature._ - - -Text-book of Palæontology - -By KARL A. VON ZITTEL, Professor of Geology and Palæontology in the -University of Munich. Translated and edited by CHARLES R. EASTMAN, Ph.D., -in charge of Vertebrate Palæontology in the Museum of Comparative Zoölogy -at Harvard College, Cambridge, Mass. - - _Vol. I. Cloth, 670 pp., with 1476 woodcuts, 8vo, $7.50 net_ - _Vol. II. Cloth, 283 pp., with 373 woodcuts, $3.00 net_ - -NOTE.—This English edition has been enlarged and revised by the author -and editor in collaboration with the following specialists: C. E. -Beecher, J. M. Clarke, W. H. Dall, G. J. Hinde, A. Hyatt, J. S. Kingsley, -H. A. Pilsbry, C. Schuchert, S. H. Scudder, W. P. Sladen, E. O. Ulrich, -C. Wachsmuth, A. S. Woodward, E. C. Case, J. B. Hatcher, H. F. Osborn, S. -W. Williston, F. A. Lucas. - - -A Text-book of General Bacteriology - -By WILLIAM DODGE FROST, Ph.D., Associate Professor of Bacteriology in the -University of Wisconsin; and EUGENE FRANKLIN McCAMPBELL, Ph.D., Associate -Professor of Bacteriology in the Ohio State University - - _Cloth, 340 pp., $1.60 net_ - - -Comparative Anatomy of Vertebrates - -Adapted from the German of DR. ROBERT WIEDERSHEIM, Professor of Anatomy, -and Director of the Institute of Human and Comparative Anatomy in the -University of Freiburg-in-Baden. By W. N. PARKER, Ph.D., Professor of -Zoölogy at the University College of South Wales and Monmouthshire in the -University of Wales - - _Cloth, 576 pp., 8vo, $3.75 net_ - - -Text-book of the Embryology of Man and Mammals - -By DR. OSCAR HERTWIG, Professor extraordinarius of Anatomy and -Comparative Anatomy, Director of the II Anatomical Institute of the -University of Berlin. Translated from the Third German Edition by EDWARD -L. MARK, Ph.D., Hersey Professor of Anatomy in Harvard University - - _Cloth, 670 pp., 8vo, $5.25 net_ - - - PUBLISHED BY - THE MACMILLAN COMPANY - 64-66 Fifth Avenue, New York - -*** END OF THE PROJECT GUTENBERG EBOOK ANIMAL INTELLIGENCE *** - -Updated editions will replace the previous one--the old editions will -be renamed. - -Creating the works from print editions not protected by U.S. copyright -law means that no one owns a United States copyright in these works, -so the Foundation (and you!) can copy and distribute it in the -United States without permission and without paying copyright -royalties. Special rules, set forth in the General Terms of Use part -of this license, apply to copying and distributing Project -Gutenberg™ electronic works to protect the PROJECT GUTENBERG™ -concept and trademark. Project Gutenberg is a registered trademark, -and may not be used if you charge for an eBook, except by following -the terms of the trademark license, including paying royalties for use -of the Project Gutenberg trademark. If you do not charge anything for -copies of this eBook, complying with the trademark license is very -easy. You may use this eBook for nearly any purpose such as creation -of derivative works, reports, performances and research. Project -Gutenberg eBooks may be modified and printed and given away--you may -do practically ANYTHING in the United States with eBooks not protected -by U.S. copyright law. Redistribution is subject to the trademark -license, especially commercial redistribution. - -START: FULL LICENSE - -THE FULL PROJECT GUTENBERG LICENSE -PLEASE READ THIS BEFORE YOU DISTRIBUTE OR USE THIS WORK - -To protect the Project Gutenberg™ mission of promoting the free -distribution of electronic works, by using or distributing this work -(or any other work associated in any way with the phrase “Project -Gutenberg”), you agree to comply with all the terms of the Full -Project Gutenberg™ License available with this file or online at -www.gutenberg.org/license. - -Section 1. General Terms of Use and Redistributing Project -Gutenberg™ electronic works - -1.A. By reading or using any part of this Project Gutenberg™ -electronic work, you indicate that you have read, understand, agree to -and accept all the terms of this license and intellectual property -(trademark/copyright) agreement. If you do not agree to abide by all -the terms of this agreement, you must cease using and return or -destroy all copies of Project Gutenberg™ electronic works in your -possession. If you paid a fee for obtaining a copy of or access to a -Project Gutenberg™ electronic work and you do not agree to be bound -by the terms of this agreement, you may obtain a refund from the -person or entity to whom you paid the fee as set forth in paragraph -1.E.8. - -1.B. “Project Gutenberg” is a registered trademark. It may only be -used on or associated in any way with an electronic work by people who -agree to be bound by the terms of this agreement. There are a few -things that you can do with most Project Gutenberg™ electronic works -even without complying with the full terms of this agreement. See -paragraph 1.C below. There are a lot of things you can do with Project -Gutenberg™ electronic works if you follow the terms of this -agreement and help preserve free future access to Project Gutenberg™ -electronic works. See paragraph 1.E below. - -1.C. The Project Gutenberg Literary Archive Foundation (“the -Foundation” or PGLAF), owns a compilation copyright in the collection -of Project Gutenberg™ electronic works. Nearly all the individual -works in the collection are in the public domain in the United -States. If an individual work is unprotected by copyright law in the -United States and you are located in the United States, we do not -claim a right to prevent you from copying, distributing, performing, -displaying or creating derivative works based on the work as long as -all references to Project Gutenberg are removed. Of course, we hope -that you will support the Project Gutenberg™ mission of promoting -free access to electronic works by freely sharing Project Gutenberg™ -works in compliance with the terms of this agreement for keeping the -Project Gutenberg™ name associated with the work. You can easily -comply with the terms of this agreement by keeping this work in the -same format with its attached full Project Gutenberg™ License when -you share it without charge with others. - -1.D. The copyright laws of the place where you are located also govern -what you can do with this work. Copyright laws in most countries are -in a constant state of change. If you are outside the United States, -check the laws of your country in addition to the terms of this -agreement before downloading, copying, displaying, performing, -distributing or creating derivative works based on this work or any -other Project Gutenberg™ work. The Foundation makes no -representations concerning the copyright status of any work in any -country other than the United States. - -1.E. Unless you have removed all references to Project Gutenberg: - -1.E.1. The following sentence, with active links to, or other -immediate access to, the full Project Gutenberg™ License must appear -prominently whenever any copy of a Project Gutenberg™ work (any work -on which the phrase “Project Gutenberg” appears, or with which the -phrase “Project Gutenberg” is associated) is accessed, displayed, -performed, viewed, copied or distributed: - - This eBook is for the use of anyone anywhere in the United States and - most other parts of the world at no cost and with almost no - restrictions whatsoever. You may copy it, give it away or re-use it - under the terms of the Project Gutenberg License included with this - eBook or online at www.gutenberg.org. If you are not located in the - United States, you will have to check the laws of the country where - you are located before using this eBook. - -1.E.2. If an individual Project Gutenberg™ electronic work is -derived from texts not protected by U.S. copyright law (does not -contain a notice indicating that it is posted with permission of the -copyright holder), the work can be copied and distributed to anyone in -the United States without paying any fees or charges. If you are -redistributing or providing access to a work with the phrase “Project -Gutenberg” associated with or appearing on the work, you must comply -either with the requirements of paragraphs 1.E.1 through 1.E.7 or -obtain permission for the use of the work and the Project Gutenberg™ -trademark as set forth in paragraphs 1.E.8 or 1.E.9. - -1.E.3. If an individual Project Gutenberg™ electronic work is posted -with the permission of the copyright holder, your use and distribution -must comply with both paragraphs 1.E.1 through 1.E.7 and any -additional terms imposed by the copyright holder. Additional terms -will be linked to the Project Gutenberg™ License for all works -posted with the permission of the copyright holder found at the -beginning of this work. - -1.E.4. Do not unlink or detach or remove the full Project Gutenberg™ -License terms from this work, or any files containing a part of this -work or any other work associated with Project Gutenberg™. - -1.E.5. Do not copy, display, perform, distribute or redistribute this -electronic work, or any part of this electronic work, without -prominently displaying the sentence set forth in paragraph 1.E.1 with -active links or immediate access to the full terms of the Project -Gutenberg™ License. - -1.E.6. You may convert to and distribute this work in any binary, -compressed, marked up, nonproprietary or proprietary form, including -any word processing or hypertext form. However, if you provide access -to or distribute copies of a Project Gutenberg™ work in a format -other than “Plain Vanilla ASCII” or other format used in the official -version posted on the official Project Gutenberg™ website -(www.gutenberg.org), you must, at no additional cost, fee or expense -to the user, provide a copy, a means of exporting a copy, or a means -of obtaining a copy upon request, of the work in its original “Plain -Vanilla ASCII” or other form. Any alternate format must include the -full Project Gutenberg™ License as specified in paragraph 1.E.1. - -1.E.7. Do not charge a fee for access to, viewing, displaying, -performing, copying or distributing any Project Gutenberg™ works -unless you comply with paragraph 1.E.8 or 1.E.9. - -1.E.8. You may charge a reasonable fee for copies of or providing -access to or distributing Project Gutenberg™ electronic works -provided that: - -• You pay a royalty fee of 20% of the gross profits you derive from - the use of Project Gutenberg™ works calculated using the method - you already use to calculate your applicable taxes. The fee is owed - to the owner of the Project Gutenberg™ trademark, but he has - agreed to donate royalties under this paragraph to the Project - Gutenberg Literary Archive Foundation. Royalty payments must be paid - within 60 days following each date on which you prepare (or are - legally required to prepare) your periodic tax returns. Royalty - payments should be clearly marked as such and sent to the Project - Gutenberg Literary Archive Foundation at the address specified in - Section 4, “Information about donations to the Project Gutenberg - Literary Archive Foundation.” - -• You provide a full refund of any money paid by a user who notifies - you in writing (or by e-mail) within 30 days of receipt that s/he - does not agree to the terms of the full Project Gutenberg™ - License. You must require such a user to return or destroy all - copies of the works possessed in a physical medium and discontinue - all use of and all access to other copies of Project Gutenberg™ - works. - -• You provide, in accordance with paragraph 1.F.3, a full refund of - any money paid for a work or a replacement copy, if a defect in the - electronic work is discovered and reported to you within 90 days of - receipt of the work. - -• You comply with all other terms of this agreement for free - distribution of Project Gutenberg™ works. - -1.E.9. If you wish to charge a fee or distribute a Project -Gutenberg™ electronic work or group of works on different terms than -are set forth in this agreement, you must obtain permission in writing -from the Project Gutenberg Literary Archive Foundation, the manager of -the Project Gutenberg™ trademark. Contact the Foundation as set -forth in Section 3 below. - -1.F. - -1.F.1. Project Gutenberg volunteers and employees expend considerable -effort to identify, do copyright research on, transcribe and proofread -works not protected by U.S. copyright law in creating the Project -Gutenberg™ collection. Despite these efforts, Project Gutenberg™ -electronic works, and the medium on which they may be stored, may -contain “Defects,” such as, but not limited to, incomplete, inaccurate -or corrupt data, transcription errors, a copyright or other -intellectual property infringement, a defective or damaged disk or -other medium, a computer virus, or computer codes that damage or -cannot be read by your equipment. - -1.F.2. LIMITED WARRANTY, DISCLAIMER OF DAMAGES - Except for the “Right -of Replacement or Refund” described in paragraph 1.F.3, the Project -Gutenberg Literary Archive Foundation, the owner of the Project -Gutenberg™ trademark, and any other party distributing a Project -Gutenberg™ electronic work under this agreement, disclaim all -liability to you for damages, costs and expenses, including legal -fees. YOU AGREE THAT YOU HAVE NO REMEDIES FOR NEGLIGENCE, STRICT -LIABILITY, BREACH OF WARRANTY OR BREACH OF CONTRACT EXCEPT THOSE -PROVIDED IN PARAGRAPH 1.F.3. YOU AGREE THAT THE FOUNDATION, THE -TRADEMARK OWNER, AND ANY DISTRIBUTOR UNDER THIS AGREEMENT WILL NOT BE -LIABLE TO YOU FOR ACTUAL, DIRECT, INDIRECT, CONSEQUENTIAL, PUNITIVE OR -INCIDENTAL DAMAGES EVEN IF YOU GIVE NOTICE OF THE POSSIBILITY OF SUCH -DAMAGE. - -1.F.3. LIMITED RIGHT OF REPLACEMENT OR REFUND - If you discover a -defect in this electronic work within 90 days of receiving it, you can -receive a refund of the money (if any) you paid for it by sending a -written explanation to the person you received the work from. If you -received the work on a physical medium, you must return the medium -with your written explanation. The person or entity that provided you -with the defective work may elect to provide a replacement copy in -lieu of a refund. If you received the work electronically, the person -or entity providing it to you may choose to give you a second -opportunity to receive the work electronically in lieu of a refund. If -the second copy is also defective, you may demand a refund in writing -without further opportunities to fix the problem. - -1.F.4. Except for the limited right of replacement or refund set forth -in paragraph 1.F.3, this work is provided to you “AS-IS”, WITH NO -OTHER WARRANTIES OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT -LIMITED TO WARRANTIES OF MERCHANTABILITY OR FITNESS FOR ANY PURPOSE. - -1.F.5. Some states do not allow disclaimers of certain implied -warranties or the exclusion or limitation of certain types of -damages. If any disclaimer or limitation set forth in this agreement -violates the law of the state applicable to this agreement, the -agreement shall be interpreted to make the maximum disclaimer or -limitation permitted by the applicable state law. The invalidity or -unenforceability of any provision of this agreement shall not void the -remaining provisions. - -1.F.6. INDEMNITY - You agree to indemnify and hold the Foundation, the -trademark owner, any agent or employee of the Foundation, anyone -providing copies of Project Gutenberg™ electronic works in -accordance with this agreement, and any volunteers associated with the -production, promotion and distribution of Project Gutenberg™ -electronic works, harmless from all liability, costs and expenses, -including legal fees, that arise directly or indirectly from any of -the following which you do or cause to occur: (a) distribution of this -or any Project Gutenberg™ work, (b) alteration, modification, or -additions or deletions to any Project Gutenberg™ work, and (c) any -Defect you cause. - -Section 2. Information about the Mission of Project Gutenberg™ - -Project Gutenberg™ is synonymous with the free distribution of -electronic works in formats readable by the widest variety of -computers including obsolete, old, middle-aged and new computers. It -exists because of the efforts of hundreds of volunteers and donations -from people in all walks of life. - -Volunteers and financial support to provide volunteers with the -assistance they need are critical to reaching Project Gutenberg™'s -goals and ensuring that the Project Gutenberg™ collection will -remain freely available for generations to come. In 2001, the Project -Gutenberg Literary Archive Foundation was created to provide a secure -and permanent future for Project Gutenberg™ and future -generations. To learn more about the Project Gutenberg Literary -Archive Foundation and how your efforts and donations can help, see -Sections 3 and 4 and the Foundation information page at -www.gutenberg.org - -Section 3. Information about the Project Gutenberg Literary -Archive Foundation - -The Project Gutenberg Literary Archive Foundation is a non-profit -501(c)(3) educational corporation organized under the laws of the -state of Mississippi and granted tax exempt status by the Internal -Revenue Service. The Foundation's EIN or federal tax identification -number is 64-6221541. Contributions to the Project Gutenberg Literary -Archive Foundation are tax deductible to the full extent permitted by -U.S. federal laws and your state's laws. - -The Foundation's business office is located at 809 North 1500 West, -Salt Lake City, UT 84116, (801) 596-1887. Email contact links and up -to date contact information can be found at the Foundation's website -and official page at www.gutenberg.org/contact - -Section 4. Information about Donations to the Project Gutenberg -Literary Archive Foundation - -Project Gutenberg™ depends upon and cannot survive without -widespread public support and donations to carry out its mission of -increasing the number of public domain and licensed works that can be -freely distributed in machine-readable form accessible by the widest -array of equipment including outdated equipment. Many small donations -($1 to $5,000) are particularly important to maintaining tax exempt -status with the IRS. - -The Foundation is committed to complying with the laws regulating -charities and charitable donations in all 50 states of the United -States. Compliance requirements are not uniform and it takes a -considerable effort, much paperwork and many fees to meet and keep up -with these requirements. We do not solicit donations in locations -where we have not received written confirmation of compliance. To SEND -DONATIONS or determine the status of compliance for any particular -state visit www.gutenberg.org/donate - -While we cannot and do not solicit contributions from states where we -have not met the solicitation requirements, we know of no prohibition -against accepting unsolicited donations from donors in such states who -approach us with offers to donate. - -International donations are gratefully accepted, but we cannot make -any statements concerning tax treatment of donations received from -outside the United States. U.S. laws alone swamp our small staff. - -Please check the Project Gutenberg web pages for current donation -methods and addresses. Donations are accepted in a number of other -ways including checks, online payments and credit card donations. To -donate, please visit: www.gutenberg.org/donate - -Section 5. General Information About Project Gutenberg™ electronic works - -Professor Michael S. Hart was the originator of the Project -Gutenberg™ concept of a library of electronic works that could be -freely shared with anyone. For forty years, he produced and -distributed Project Gutenberg™ eBooks with only a loose network of -volunteer support. - -Project Gutenberg™ eBooks are often created from several printed -editions, all of which are confirmed as not protected by copyright in -the U.S. unless a copyright notice is included. Thus, we do not -necessarily keep eBooks in compliance with any particular paper -edition. - -Most people start at our website which has the main PG search -facility: www.gutenberg.org - -This website includes information about Project Gutenberg™, -including how to make donations to the Project Gutenberg Literary -Archive Foundation, how to help produce our new eBooks, and how to -subscribe to our email newsletter to hear about new eBooks. diff --git a/old/69904-0.zip b/old/69904-0.zip Binary files differdeleted file mode 100644 index 7c9d3b0..0000000 --- a/old/69904-0.zip +++ /dev/null diff --git a/old/69904-h.zip b/old/69904-h.zip Binary files differdeleted file mode 100644 index 631ae08..0000000 --- a/old/69904-h.zip +++ /dev/null diff --git a/old/69904-h/69904-h.htm b/old/69904-h/69904-h.htm deleted file mode 100644 index 7e8af5a..0000000 --- a/old/69904-h/69904-h.htm +++ /dev/null @@ -1,14617 +0,0 @@ -<!DOCTYPE html> -<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en"> - <head> - <meta charset="UTF-8"> - <title> - Animal Intelligence | Project Gutenberg - </title> - - <link rel="icon" href="images/cover.jpg" type="image/x-cover"> - - <style> - -a { - text-decoration: none; -} - -body { - margin-left: 10%; - margin-right: 10%; -} - -h1,h2,h3,h4,h5 { - text-align: center; - clear: both; -} - -h2.nobreak { - page-break-before: avoid; -} - -hr.chap { - margin-top: 2em; - margin-bottom: 2em; - clear: both; - width: 65%; - margin-left: 17.5%; - margin-right: 17.5%; -} - -img.w100 { - width: 100%; -} - -div.chapter { - page-break-before: always; -} - -ul { - list-style-type: none; -} - -li.indx { - margin-top: .5em; - padding-left: 2em; - text-indent: -2em; -} - -li.ifrst { - margin-top: 2em; - padding-left: 2em; - text-indent: -2em; -} - -li.isub1 { - padding-left: 4em; - text-indent: -2em; -} - -p { - margin-top: 0.5em; - text-align: justify; - margin-bottom: 0.5em; - text-indent: 1em; -} - -table { - margin: 1em auto 1em auto; - max-width: 40em; - border-collapse: collapse; -} - -table.max60 { - max-width: 60em; - font-size: 90%; -} - -th { - padding: 0.25em; - font-weight: normal; -} - -td { - padding: 0 0.25em; -} - -table.align-top td { - vertical-align: top; -} - -table.borders { - border-bottom: double black; - border-top: double black; -} - -.borders th { - border-left: thin solid black; - border-bottom: thin solid black; - border-top: thin solid black; -} - -.borders td { - border-left: thin solid black; -} - -.borders .nobl, .borders td:first-child, .borders th:first-child { - border-left: none; -} - -.borders tr:last-child td, .borders tr:last-child th { - border-bottom: thin solid black; -} - -.contents td { - padding-left: 2.25em; - padding-right: 0.25em; - vertical-align: top; - text-indent: -2em; -} - -.contents tr.chap td, .borders tr.new td { - padding-top: 0.5em; -} - -.contents .h3 { - padding-left: 3.25em; -} - -.contents .h4 { - padding-left: 4.25em; -} - -.contents .tdpg { - vertical-align: bottom; - text-align: right; -} - -.bb {border-bottom: thin solid black;} -.bl {border-left: thin solid black;} -.br, .borders tr:last-child td.br {border-right: thin solid black;} -.bt {border-top: thin solid black;} -.bt2 {border-top: double black;} - -.tdc { - text-align: center; -} - -.tdr { - text-align: right; -} - -.author { - text-indent: 0; -} - -.blockquote { - margin: 1.5em 10%; -} - -.book { - margin-top: 0.75em; - font-size: 150%; - margin-left: -1em; - text-indent: 0; -} - -.box { - margin: auto; - padding: 0.5em; - border: thin solid black; - max-width: 25em; -} - -.caption { - text-align: center; - margin-bottom: 1em; - font-size: 90%; - text-indent: 0em; -} - -.center { - text-align: center; - text-indent: 0em; -} - -.figcenter { - margin: auto; - text-align: center; -} - -.footnotes { - margin-top: 1em; - border: dashed 1px; -} - -.footnote { - margin-left: 10%; - margin-right: 10%; - font-size: 0.9em; -} - -.footnote .label { - position: absolute; - right: 84%; - text-align: right; -} - -.fnanchor { - vertical-align: super; - font-size: .8em; - text-decoration: none; -} - -.gothic { - font-family: 'Old English Text MT', 'Old English', serif; -} - -.larger { - font-size: 150%; -} - -.largest { - font-size: 175%; -} - -.noindent { - text-indent: 0em; -} - -.nw { - white-space: nowrap; -} - -.pagenum { - position: absolute; - right: 4%; - font-size: smaller; - text-align: right; - font-style: normal; -} - -.right { - text-align: right; -} - -.smaller { - font-size: 80%; -} - -.smcap { - font-variant: small-caps; - font-style: normal; -} - -.tb { - margin-top: 2em; -} - -.titlepage { - text-align: center; - margin-top: 3em; - text-indent: 0em; -} - -.x-ebookmaker img { - max-width: 100%; - width: auto; - height: auto; -} - -.x-ebookmaker .blockquote { - margin: 1.5em 5%; -} - -/* Illustration classes */ -.illowp100 {width: 100%;} -.illowp48 {width: 48%;} -.x-ebookmaker .illowp48 {width: 100%;} -.illowp50 {width: 50%;} -.x-ebookmaker .illowp50 {width: 100%;} -.illowp75 {width: 75%;} -.x-ebookmaker .illowp75 {width: 100%;} -.illowp95 {width: 95%;} -.x-ebookmaker .illowp95 {width: 100%;} - </style> - </head> -<body> -<p style='text-align:center; font-size:1.2em; font-weight:bold'>The Project Gutenberg eBook of Animal intelligence, by Edward Lee Thorndike</p> -<div style='display:block; margin:1em 0'> -This eBook is for the use of anyone anywhere in the United States and -most other parts of the world at no cost and with almost no restrictions -whatsoever. You may copy it, give it away or re-use it under the terms -of the Project Gutenberg License included with this eBook or online -at <a href="https://www.gutenberg.org">www.gutenberg.org</a>. If you -are not located in the United States, you will have to check the laws of the -country where you are located before using this eBook. -</div> - -<p style='display:block; margin-top:1em; margin-bottom:0; margin-left:2em; text-indent:-2em'>Title: Animal intelligence</p> -<p style='display:block; margin-left:2em; text-indent:0; margin-top:0; margin-bottom:1em;'>Experimental studies</p> -<p style='display:block; margin-top:1em; margin-bottom:0; margin-left:2em; text-indent:-2em'>Author: Edward Lee Thorndike</p> -<p style='display:block; text-indent:0; margin:1em 0'>Release Date: January 29, 2023 [eBook #69904]</p> -<p style='display:block; text-indent:0; margin:1em 0'>Language: English</p> - <p style='display:block; margin-top:1em; margin-bottom:0; margin-left:2em; text-indent:-2em; text-align:left'>Produced by: Emmanuel Ackerman, Kobus Meyer and the Online Distributed Proofreading Team at https://www.pgdp.net (This file was produced from images generously made available by The Internet Archive)</p> -<div style='margin-top:2em; margin-bottom:4em'>*** START OF THE PROJECT GUTENBERG EBOOK ANIMAL INTELLIGENCE ***</div> - -<p><span class="pagenum"><a id="Page_i"></a>[i]</span></p> - -<p class="center largest">ANIMAL INTELLIGENCE</p> - -<p><span class="pagenum"><a id="Page_ii"></a>[ii]</span></p> - -<div class="figcenter illowp100" id="macmillan" style="max-width: 18.75em;"> - <img class="w100" src="images/macmillan.jpg" alt=""> -</div> - -<p class="center">THE MACMILLAN COMPANY<br> -<span class="smaller">NEW YORK · BOSTON · CHICAGO<br> -SAN FRANCISCO</span></p> - -<p class="center"><span class="smcap">MACMILLAN & CO., Limited</span><br> -<span class="smaller">LONDON · BOMBAY · CALCUTTA<br> -MELBOURNE</span></p> - -<p class="center"><span class="smcap">THE MACMILLAN CO. OF CANADA, Ltd.</span><br> -<span class="smaller">TORONTO</span></p> - -<hr class="chap x-ebookmaker-drop"> - -<p><span class="pagenum"><a id="Page_iii"></a>[iii]</span></p> - -<p class="titlepage largest">ANIMAL INTELLIGENCE</p> - -<p class="center larger">EXPERIMENTAL STUDIES</p> - -<p class="titlepage"><span class="smaller">BY</span><br> -EDWARD L. THORNDIKE<br> -<span class="smaller">TEACHERS COLLEGE, COLUMBIA UNIVERSITY</span></p> - -<p class="titlepage"><span class="gothic">New York</span><br> -THE MACMILLAN COMPANY<br> -1911</p> - -<p class="center smaller"><i>All rights reserved</i></p> - -<p><span class="pagenum"><a id="Page_iv"></a>[iv]</span></p> - -<p class="titlepage smaller"><span class="smcap">Copyright, 1911,<br> -By THE MACMILLAN COMPANY.</span></p> - -<p class="center smaller">Set up and electrotyped. Published June, 1911.</p> - -<p class="titlepage smaller"><span class="gothic">Norwood Press</span><br> -J. S. Cushing Co.—Berwick & Smith Co.<br> -Norwood, Mass., U.S.A.</p> - -<hr class="chap x-ebookmaker-drop"> - -<div class="chapter"> - -<p><span class="pagenum"><a id="Page_v"></a>[v]</span></p> - -<h2 class="nobreak" id="PREFACE">PREFACE</h2> - -</div> - -<p>The main purpose of this volume is to make accessible -to students of psychology and biology the author’s experimental -studies of animal intellect and behavior.<a id="FNanchor_1" href="#Footnote_1" class="fnanchor">[1]</a> These -studies have, I am informed by teachers of comparative -psychology, a twofold interest. Since they represent the -first deliberate and extended application of the experimental -method in animal psychology, they are a useful -introduction to the later literature of that subject. They -mark the change from books of general argumentation -on the basis of common experience interpreted in terms -of the faculty psychology, to monographs reporting detailed -and often highly technical experiments interpreted -in terms of original and acquired connections between -situation and response. Since they represent the point -of view and the method of present animal psychology, but -in the case of very general and simple problems, they are -useful also as readings for students who need a general -acquaintance with some sample of experimental work in -this field.</p> - -<p><span class="pagenum"><a id="Page_vi"></a>[vi]</span></p> - -<p>It has seemed best to leave the texts unaltered except -for the correction of typographical errors, renumbering -of tables and figures, and redrawing the latter. In a -few places, where the original text has been found likely -to be misunderstood, brief notes have been added. It is -hard to resist the impulse to temper the style, especially -of the ‘Animal Intelligence,’ with a certain sobriety and -restraint. What one writes at the age of twenty-three -is likely to irritate oneself a dozen years later, as it doubtless -irritated others at the time. The charitable reader -may allay his irritation by the thought that a degree of -exuberance, even of arrogance, is proper to youth.</p> - -<p>To the reports of experimental studies are added two -new essays dealing with the general laws of human and -animal learning.</p> - -<p><span class="smcap">January, 1911.</span></p> - -<hr class="chap x-ebookmaker-drop"> - -<div class="chapter"> - -<p><span class="pagenum"><a id="Page_vii"></a>[vii]</span></p> - -<h2 class="nobreak">CONTENTS</h2> - -</div> - -<table class="contents"> - <tr> - <td></td> - <td class="tdpg smaller">PAGE</td> - </tr> - <tr class="chap"> - <td><span class="smcap">The Study of Consciousness and the Study of Behavior</span></td> - <td class="tdpg"><a href="#CHAPTER_I">1</a></td> - </tr> - <tr class="chap"> - <td><span class="smcap">Animal Intelligence</span></td> - <td class="tdpg"><a href="#CHAPTER_II">20</a></td> - </tr> - <tr> - <td class="h3">Introduction</td> - <td class="tdpg"><a href="#Page_20">20</a></td> - </tr> - <tr> - <td class="h3">Description of Apparatus</td> - <td class="tdpg"><a href="#Page_29">29</a></td> - </tr> - <tr> - <td class="h3">Experiments with Cats</td> - <td class="tdpg"><a href="#Page_35">35</a></td> - </tr> - <tr> - <td class="h3">Experiments with Dogs</td> - <td class="tdpg"><a href="#Page_56">56</a></td> - </tr> - <tr> - <td class="h3">Experiments with Chicks</td> - <td class="tdpg"><a href="#Page_61">61</a></td> - </tr> - <tr> - <td class="h3">Reasoning or Inference</td> - <td class="tdpg"><a href="#Page_67">67</a></td> - </tr> - <tr> - <td class="h3">Imitation</td> - <td class="tdpg"><a href="#Page_76">76</a></td> - </tr> - <tr> - <td class="h4">In Chicks</td> - <td class="tdpg"><a href="#Page_81">81</a></td> - </tr> - <tr> - <td class="h4">In Cats</td> - <td class="tdpg"><a href="#Page_85">85</a></td> - </tr> - <tr> - <td class="h4">In Dogs</td> - <td class="tdpg"><a href="#Page_92">92</a></td> - </tr> - <tr> - <td class="h3">The Mental Fact in Association</td> - <td class="tdpg"><a href="#Page_98">98</a></td> - </tr> - <tr> - <td class="h3">Association by Similarity and the Formation of Concepts</td> - <td class="tdpg"><a href="#Page_116">116</a></td> - </tr> - <tr> - <td class="h3">Criticism of Previous Theories</td> - <td class="tdpg"><a href="#Page_125">125</a></td> - </tr> - <tr> - <td class="h3">Delicacy of Association</td> - <td class="tdpg"><a href="#Page_128">128</a></td> - </tr> - <tr> - <td class="h3">Complexity of Associations</td> - <td class="tdpg"><a href="#Page_132">132</a></td> - </tr> - <tr> - <td class="h3">Number of Associations</td> - <td class="tdpg"><a href="#Page_135">135</a></td> - </tr> - <tr> - <td class="h3">Permanence of Associations</td> - <td class="tdpg"><a href="#Page_138">138</a></td> - </tr> - <tr> - <td class="h3">Inhibition of Instincts by Habit</td> - <td class="tdpg"><a href="#Page_142">142</a></td> - </tr> - <tr> - <td class="h3">Attention</td> - <td class="tdpg"><a href="#Page_144">144</a></td> - </tr> - <tr> - <td class="h3">The Social Consciousness of Animals</td> - <td class="tdpg"><a href="#Page_146">146</a></td> - </tr> - <tr> - <td class="h3">Interaction</td> - <td class="tdpg"><a href="#Page_147">147</a></td> - </tr> - <tr> - <td class="h3">Applications to Pedagogy, Anthropology, etc.</td> - <td class="tdpg"><a href="#Page_149">149</a></td> - </tr> - <tr> - <td class="h3">Conclusion</td> - <td class="tdpg"><a href="#Page_153">153</a></td> - </tr> - <tr class="chap"> - <td><span class="smcap">The Instinctive Reactions of Young Chicks</span></td> - <td class="tdpg"><a href="#CHAPTER_III">156</a></td> - </tr> - <tr class="chap"> - <td><span class="smcap">A Note on the Psychology of Fishes</span></td> - <td class="tdpg"><a href="#CHAPTER_IV">169</a></td> - </tr> - <tr class="chap"> - <td><span class="smcap">The Mental Life of the Monkeys</span></td> - <td class="tdpg"><a href="#CHAPTER_V">172</a></td> - </tr> - <tr> - <td class="h3">Introduction</td> - <td class="tdpg"><a href="#Page_173">173</a></td> - </tr> - <tr> - <td class="h3">Apparatus</td> - <td class="tdpg"><a href="#Page_177">177</a><span class="pagenum"><a id="Page_viii"></a>[viii]</span></td> - </tr> - <tr> - <td class="h3">Learning without Tuition</td> - <td class="tdpg"><a href="#Page_182">182</a></td> - </tr> - <tr> - <td class="h4">Tests with Mechanisms</td> - <td class="tdpg"><a href="#Page_184">184</a></td> - </tr> - <tr> - <td class="h4">Tests with Signals</td> - <td class="tdpg"><a href="#Page_195">195</a></td> - </tr> - <tr> - <td class="h3">Experiments on the Influence of Tuition</td> - <td class="tdpg"><a href="#Page_209">209</a></td> - </tr> - <tr> - <td class="h4">Introduction</td> - <td class="tdpg"><a href="#Page_209">209</a></td> - </tr> - <tr> - <td class="h4">Imitation of Human Beings</td> - <td class="tdpg"><a href="#Page_211">211</a></td> - </tr> - <tr> - <td class="h4">Imitation of Other Monkeys</td> - <td class="tdpg"><a href="#Page_219">219</a></td> - </tr> - <tr> - <td class="h4">Learning apart from Motor Impulses</td> - <td class="tdpg"><a href="#Page_222">222</a></td> - </tr> - <tr> - <td class="h3">General Mental Development of the Monkeys</td> - <td class="tdpg"><a href="#Page_236">236</a></td> - </tr> - <tr class="chap"> - <td><span class="smcap">Laws and Hypotheses of Behavior</span></td> - <td class="tdpg"><a href="#CHAPTER_VI">241</a></td> - </tr> - <tr class="chap"> - <td><span class="smcap">The Evolution of the Human Intellect</span></td> - <td class="tdpg"><a href="#CHAPTER_VII">282</a></td> - </tr> -</table> - -<hr class="chap x-ebookmaker-drop"> - -<div class="chapter"> - -<p><span class="pagenum"><a id="Page_1"></a>[1]</span></p> - -<h1>ANIMAL INTELLIGENCE</h1> - -<h2 class="nobreak" id="CHAPTER_I">CHAPTER I<br> -<span class="smcap">The Study of Consciousness and the Study of Behavior</span></h2> - -</div> - -<p>The statements about human nature made by psychologists -are of two sorts,—statements about <i>consciousness</i>, -about the inner life of thought and feeling, the ‘self as -conscious,’ the ‘stream of thought’; and statements about -<i>behavior</i>, about the life of man that is left unexplained -by physics, chemistry, anatomy and physiology, and is -roughly compassed for common sense by the terms ‘intellect’ -and ‘character.’</p> - -<p>Animal psychology shows the same double content. -Some statements concern the conscious states of the animal, -what he is to himself as an inner life; others concern his -original and acquired ways of response, his behavior, what -he is to an outside observer.</p> - -<p>Of the psychological terms in common use, some refer -only to conscious states, and some refer to behavior regardless -of the consciousness accompanying it; but the majority -are ambiguous, referring to the man or animal in question, -at times in his aspect of inner life, at times in his aspect of -reacting organism, and at times as an undefined total -nature. Thus ‘intensity,’ ‘duration’ and ‘quality’ of -sensations, ‘transitive’ and ‘substantive’ states and ‘imagery’ -almost inevitably refer to states of consciousness.<span class="pagenum"><a id="Page_2"></a>[2]</span> -‘Imitation,’ ‘invention’ and ‘practice’ almost -inevitably refer to behavior observed from the outside. -‘Perception,’ ‘attention,’ ‘memory,’ ‘abstraction,’ ‘reasoning’ -and ‘will’ are samples of the many terms which -illustrate both ways of studying human and animal -minds. That an animal perceives an object, say, the sun, -may mean either that his mental stream includes an awareness -of that object distinguished from the rest of the visual -field; or that he reacts to that object as a unit. ‘Attention’ -may mean a clearness, focalness, of the mental state; -or an exclusiveness and devotion of the total behavior. It -may, that is, be illustrated by the sharpness of objects -illumined by a shaft of light, or by the behavior of a cat -toward the bird it stalks. ‘Memory’ may be consciousness -of certain objects, events or facts; or may be the permanence -of certain tendencies in either thought or action. -‘To recognize’ may be to feel a certain familiarity and -surety of being able to progress to certain judgments about -the thing recognized; or may be to respond to it in certain -accustomed and appropriate ways. ‘Abstraction’ may -refer to ideas of qualities apart from any consciousness of -their concrete accompaniments, and to the power of having -such ideas; or to responses to qualities irrespective of their -concrete accompaniments, and to the power of making such -responses. ‘Reasoning’ may be said to be present when -certain sorts of consciousness, or when certain sorts of -behavior, are present. An account of ‘the will’ is an -account of consciousness as related to action or an account -of the actions themselves.</p> - -<p>Not only in psychological judgments and psychological -terms, but also in the work of individual psychologists, -this twofold content is seen. Amongst writers in this -country, for example, Titchener has busied himself almost<span class="pagenum"><a id="Page_3"></a>[3]</span> -exclusively with consciousness ‘as such’; Stanley Hall, -with behavior; and James, with both. In England Stout, -Galton and Lloyd Morgan have represented the same division -and union of interests.</p> - -<p>On the whole, the psychological work of the last quarter -of the nineteenth century emphasized the study of consciousness -to the neglect of the total life of intellect and character. -There was a tendency to an unwise, if not bigoted, attempt -to make the science of human nature synonymous with the -science of facts revealed by introspection. It was, for -example, pretended that the only value of all the measurements -of reaction-times was as a means to insight into the -reaction-consciousness,—that the measurements of the -amount of objective difference in the length, brightness or -weight of two objects that men could judge with an assigned -degree of correctness were of value only so far as they -allowed one to infer something about the difference between -two corresponding consciousnesses. It was affirmed that -experimental methods were not to aid the experimenter to -know what the subject did, but to aid the subject to know -what he experienced.</p> - -<p>The restriction of studies of human intellect and character -to studies of conscious states was not without influence on -scientific studies of animal psychology. For one thing, it -probably delayed them. So long as introspection was -lauded as the chief method of psychology, a psychologist -would tend to expect too little from mere studies, from the -outside, of creatures who could not report their inner experiences -to him in the manner to which he was accustomed. -In the literature of the time will be found many comments -on the extreme difficulty of studying the psychology of -animals and children. But difficulty exists only in the -case of their <i>consciousness</i>. Their <i>behavior</i>, by its simpler<span class="pagenum"><a id="Page_4"></a>[4]</span> -nature and causation, is often far easier to study than that -of adults. Again, much time was spent in argumentation -about the criteria of consciousness, that is, about what certain -common facts of behavior meant in reference to inner -experience. The problems of inference about consciousness -from behavior distracted attention from the problems of -learning more about behavior itself. Finally, when psychologists -began to observe and experiment upon animal -behavior, they tended to overestimate the resulting insight -into the stream of the animal’s thought and to neglect -the direct facts about what he did and how he did it.</p> - -<p>Such observations and experiments are, however, themselves -a means of restoring a proper division of attention -between consciousness and behavior. A psychologist -may think of himself as chiefly a stream of consciousness. -He may even think of other men as chiefly conscious -selves whose histories they report by word and deed. But -it is only by an extreme bigotry that he can think of a dog -or cat as chiefly a stream or chain or series of consciousness -or consciousnesses. One of the lower animals is so obviously -a bundle of original and acquired connections between -situation and response that the student is led to -attend to the whole series,—situation, response and connection -or bond,—rather than to just the conscious state -that may or may not be one of the features of the bond. -It is so useful, in understanding the animal, to see what it -does in different circumstances and what helps and what -hinders its learning, that one is led to an intrinsic interest -in varieties of behavior as well as in the kinds of consciousness -of which they give evidence.</p> - -<p>What each open-minded student of animal psychology -at first hand comes thus to feel vaguely, I propose in this -essay to try to make definite and clear. The studies<span class="pagenum"><a id="Page_5"></a>[5]</span> -reprinted in this volume produced in their author an increased -respect for psychology as the science of behavior, -a willingness to make psychology continuous with physiology, -and a surety that to study consciousness for the sake -of inferring what a man can or will do, is as proper as to -study behavior for the sake of inferring what conscious -states he can or will have. This essay will attempt to -defend these positions and to show further that psychology -may be, at least in part, as independent of introspection -as physics is.</p> - -<p>A psychologist who wishes to broaden the content of -the science to include all that biology includes under the -term ‘behavior,’ or all that common sense means by the -words ‘intellect’ and ‘character,’ has to meet certain -objections. The first is the indefiniteness of this content.</p> - -<p>The indefiniteness is a fact, but is not in itself objectionable. -It is true that by an animal’s behavior one means -the facts about the animal that are left over after geometry, -physics, chemistry, anatomy and physiology have taken -their toll, and that are not already well looked after by -sociology, economics, history, esthetics and other sciences -dealing with certain complex and specialized facts of behavior. -It is true that the boundaries of psychology, -from physiology on the one hand, and from sociology, -economics and the like on the other, become dubious and -changeable. But this is in general a sign of a healthy -condition in a science. The pretense that there is an impassable -cleft between physiology and psychology should -arouse suspicion that one or the other science is studying -words rather than realities.</p> - -<p>The same holds against the objection that, if psychology -is the science of behavior, it will be swallowed up by biology. -When a body of facts treated subjectively, vaguely<span class="pagenum"><a id="Page_6"></a>[6]</span> -and without quantitative precision by one science or group -of scientists comes to be treated more objectively, definitely -and exactly by another, it is of course a gain, a symptom of -the general advance of science. That geology may become -a part of physics, or physiology a part of chemistry, is testimony -to the advance of geology and physiology. Light -is no less worthy of study by being found to be explainable -by laws discovered in the study of electricity. Meteorology -had to reach a relatively high development to provoke -the wit to say that “All the science in meteorology is -physics, the rest is wind.”</p> - -<p>These objections to be significant should frankly assert -that between physical facts and mental facts, between -bodies and minds, between any and all of the animal’s -movements and its states of consciousness, there is an impassable -gap, a real discontinuity, found nowhere else in -science; and that by making psychology responsible for -territory on both sides of the gap, one makes psychology -include two totally disparate groups of facts, things and -thoughts, requiring totally different methods of study. -This is, of course, the traditional view of the scope of -psychology, reiterated in the introductions to the standard -books and often accepted in theory as axiomatic.</p> - -<p>It has, however, already been noted that in practice -psychologists do study facts in disregard of this supposed -gap, that the same term refers to facts belonging some on -one side of it and some on the other, and that, in animal -psychology, it seems very unprofitable to try to keep on -one side or the other. Moreover, the practice to which the -study of animal and child psychology leads is, if I understand -their writings, justified as a matter of theory by -Dewey and Santayana. If then, as a matter of scientific -fact, human and animal behavior, with or without consciousness,<span class="pagenum"><a id="Page_7"></a>[7]</span> -seems a suitable subject for a scientific student, -we may study it without a too uneasy sense of philosophic -heresy and guilt.</p> - -<p>The writer must confess not only to the absence of any special -reverence for the supposed axiom, but also to the presence -of a conviction that it is false, the truth being that -whatever feature of any animal, say John Smith, of <i>Homo -sapiens</i>, is studied—its length, its color of hair, its body -temperature, its toothache, its anxiety, or its thinking of -9 × 7—the attitude and methods of the student may properly -be substantially the same.</p> - -<p>Of the six facts in the illustration just given, the last -three would by the traditional view be all much alike for -study, and all much unlike any of the first three. The -same kind of science, physical science, would be potent for -the first three and impotent for the last three (save to give -facts about certain physical facts which ‘paralleled’ them). -Conversely one kind of science, psychology, would by the -traditional view deal with the last three, but have nothing -to say about the first three.</p> - -<p>But is there in actual fact any such radical dichotomy -of these six facts as objects of science? Take any task -of science with respect to them, for example, identification. -A score of scientific men, including John Smith himself, are -asked to identify John’s stature at a given moment. Each -observes it carefully, getting, let us say, as measures: 72.10 -inches, 72.11, 72.05, 72.08, 72.09, 72.11, etc.</p> - -<p>In the case of color of hair each observes as before, the -reports being brown, light brown, brown, light brown, -between light brown and brown, and so forth.</p> - -<p>In the case of body temperature, again, each observes -as before, there being the same variability in the reports; -but John <i>may also observe in a second way</i>, not by observing<span class="pagenum"><a id="Page_8"></a>[8]</span> -a thermometer with eyes, but by observing the temperature -of his body through other sense-organs so situated that -they lead to knowledge of only his own body’s temperature. -It is important to note that for efficient knowledge -of his own body-temperature, John does not use the sense -approach peculiar to him, but that available for all observers. -He identifies and measures his ‘feverishness’ by -studying himself as he would study any other animal, by -thermometer and eye.</p> - -<p>In the case of the toothache the students proceed as -before, except that they use John’s gestures, facial expression, -cries and verbal reports, as well as his mere -bodily structure and condition. They not only observe the -cavities in his teeth, the signs of ulcer and the like, but they -also ask him, tapping a tooth, “Does it hurt?” “How -long has it hurt?” “Does it hurt very much?” and the -like. John, if their equal in knowledge of dentistry, would -use the same methods, testing himself, asking himself -questions and using the replies made by himself to himself -in inner speech. But, as with temperature, he would get -data, for his identification of the toothache, from a source -unavailable for the others, the sense-organs in his teeth.</p> - -<p>It is worth while to consider how they and he would proceed -to an exact identification or measure of the intensity -of his toothache such as was made of his stature or body-temperature. -First, they would need a scale of toothaches -of varying intensities. Next, they would need means of -comparing the intensity of his toothache with those of -this scale to see which it was most like. Given this scale -and means of comparison, they would turn John’s attention -from the original toothache to one of given intensity, and -compare the two, both by his facial expression, gestures and -the like, and by the verbal reports made. John would<span class="pagenum"><a id="Page_9"></a>[9]</span> -do likewise, reporting to himself instead of to them. The -similarity of the procedure to that in studying a so-called -physical fact is still clearer if we suppose a primitive condition -of the scales of length and temperature. Suppose -for example that for the length of a man we had only -‘short’ or ‘tall as a deer,’ ‘medium’ or ‘tall as a moose,’ -and ‘tall’ or ‘tall as a horse’; and for the intensity of the -toothache of a man ‘little’ or ‘intense as a pin-prick,’ -‘medium’ or ‘intense as a knife-cut,’ and ‘great’ or ‘intense -as a spear-thrust.’ Then obviously the only difference -between the identification of the length of a man’s body and -the identification of the intensity of his toothache would -be that the latter was made by all on the basis of behavior -as well as anatomy, and made by the individual having -it on the basis of data from an additional sense-organ.</p> - -<p>In actual present practice, if observers were asked to -identify the intensity of John’s toothache on a scale running -from zero intensity up, the variability of the reports -would be very great in comparison with those of stature -or body-temperature. Supposing the most intense toothache -to be called <i>K</i>, we might well have reports of from -say .300 <i>K</i> to .450 <i>K</i>, some observers identifying the fact -with a condition one and a half times as intense as that -chosen by others. But such a variability might also occur -in primitive men’s judgments of length or temperature.</p> - -<p>It is important to note that the accuracy of John’s own -identification of it depends in any case on his knowledge -of the scale and his power of comparing his toothache therewith. -Well-trained outside observers might identify the -intensity of John’s toothache more accurately than he -could.</p> - -<p>In the case of John’s anxiety, the most striking fact is -the low degree of accuracy in identification. The quality of<span class="pagenum"><a id="Page_10"></a>[10]</span> -the anxiety and its intensity would both be so crudely -measured by present means that even if the observers -were from the score of most competent psychologists, their -reports would probably be not much better than, say, the -descriptions now found in masterpieces of fiction and drama. -Science could not tell at all closely how much John’s anxiety -at this particular time resembled either his anxiety on -some other occasion or anything else. This inferiority -is due in part to the fact that the manifestations of anxiety -in behavior, including verbal reports, are so complicated -by facts other than the anxiety itself, by, for example, -the animal’s health, temperament, concomitant ideas -and emotions, knowledge of language, clearness in expression -and the like. It is due in part to the very low status -of our classification of kinds of anxieties and of our units -and scales for measuring the amount of each kind. Hence -the variation amongst observers would be even greater -than in the case of the toothache, and the confidence of -all in their judgments would be less, and far, far less than -their confidence in their judgment of John’s stature. The -best possible present knowledge of John’s anxiety, though -scientific in comparison with ordinary opinion about it, -would seem grossly unscientific in comparison with knowledge -of his stature or weight. Knowledge of the anxiety -would improve with better knowledge of its manifestations, -including verbal reports by John, and with better means of -classification and measurement.</p> - -<p>John’s knowledge of his own anxiety would be in part the -same as that of the other observers. He too would judge -his condition by its external manifestations, would name -its sort and rate its amount on the basis of his own behavior, -as he saw his own face, heard his own groans, and read the -notes he wrote describing his condition. But he would<span class="pagenum"><a id="Page_11"></a>[11]</span> -also, as with the toothache, have data from internal sense-organs -and perhaps from centrally initiated neural actions. -In so far as he could report these data to himself for use -in scientific thought more efficiently than he could report -them to the other observers, he would have, as with the -toothache, an advantage comparable to the advantage -of a criminologist who happened also to be or to have been -a thief, or of a literary critic who happened to have written -what he judged. It is important to note that only in so -far as he who has ‘immediate experience’ of or participates -in or is ‘directly conscious’ of the anxiety, reports it to -himself as thinker or scientific student, in common with -the other nineteen, that this advantage accrues. To -really <i>be</i> or <i>have</i> the anxiety is not to correctly <i>know</i> it. -An insane man must become sane in order to know his -insane condition. Bigotry, stupidity and false reasoning -can be understood only by one who never was them or has -ceased to be them.</p> - -<p>In our last illustration, John’s thinking of ‘9 × 7 equals -63,’ the effect on John’s behavior may be so complicated -by other conditions in John, and is so subject to the particular -conditions which we name John’s ‘will,’ that the -observers would often be at loss except for John’s verbal -report. Not that the observer is restricted to that. If -John does the example 217 × 69 in the usual way, it is a very -safe inference that he thought 9 × 7 equals 63, regardless -of the absence of a verbal report from him. But often there -is little else to go by. To John himself, on the contrary, -it is easier to be sure that he is thinking of 9 × 7 equals -63, than that he has a particular sort and strength of toothache. -Consequently if we suppose John to be thinking -of that fact while under observation, and the twenty observers<span class="pagenum"><a id="Page_12"></a>[12]</span> -to be required to identify the fact he is thinking -of, it is sure that there might be an enormous variability in -their guesses as to what the fact was and that his testimony -might be worth far more than that of all the other nineteen -without his testimony. His observation is influenced by -the action of the neurones in his central nervous system as -theirs is not, and, in the case of the thought ‘9 × 7 equals -63,’ the action of these neurones is of special importance.</p> - -<p>Our examination of the way science treats these six facts -shows no impassable cleft between knowledge of a man’s -body and knowledge of his mind. Scientific statements -about the toothache, anxiety and numerical judgment are -in general more variable than statements about length, -hair-color and body-temperature, but there is here no -difference save of degree. Some physical facts, such as -hair-color, eye-color or health, are, in fact, judged more -variably than some mental facts, such as rate of adding, -accuracy of perception of a certain sort and the like. So -far as the lack of agreement amongst impartial observers -goes, there is continuity from the identification of a length -to that of an ideal.</p> - -<p>Scientific judgments about the facts of John’s mind -also depend, in general, more upon his verbal reports than -do judgments about his body. But here also the difference -is only of degree. The physician studying wounds, ulcers, -tumors, infections and other facts of a man’s body may -depend more upon his verbal reports than does the moralist -who is studying the man’s character. Verbal reports -too are themselves a gradual and continuous extension of -coarser forms of behavior. They signify consciousness -no more truly than do signs, gestures, facial expression -and the general bodily motions of pursuit, retreat, avoidance -or seizure.</p> - -<p><span class="pagenum"><a id="Page_13"></a>[13]</span></p> - -<p>Nor is it true that physical facts are known to many -observers and mental facts to but one, who <i>is</i> or <i>has</i> or -<i>directly experiences</i> them. If it were true, sociology, -economics, history, anthropology and the like would -either be physical sciences or represent no knowledge at -all. The kind of knowledge of which these sciences and -the common judgments of our fellow men are made up is -knowledge possessed by many observers in common, the -individual of whom the facts is known, knowing the fact -in part in just the same way that the others know it.</p> - -<p>The real difference between a man’s scientific judgments -about himself and the judgment of others about him is -that he has <i>added sources of knowledge</i>. Much of what -goes on in him influences him in ways other than those -in which it influences other men. But this difference is -not coterminous with that between judgments about his -‘mind’ and about his ‘body.’ As was pointed out in the -case of body-temperature, a man knows certain facts about -his own body in such additional ways.</p> - -<p>Furthermore, there is no more truth in the statement -that a man’s pain or anxiety or opinions are matters of -direct consciousness, pure experience, than in the statement -that his length, weight and temperature are, or that the sun, -moon and stars are. If by the pain we must mean the pain -as felt by some one, then by the sun we can mean only the -sun as seen by some one. Pain and sun are equally subjects -for a science of ‘consciousness as such.’ But if by the -sun is meant the sun of common sense, physics and astronomy, -the sun as known by any one, then by the pain we -can mean the pain of medicine, economics and sociology, the -pain as known by any one, and by the sufferer long after -he <i>was</i> or <i>had</i> it.</p> - -<p>All facts emerge from the matrix of pure experience;<span class="pagenum"><a id="Page_14"></a>[14]</span> -but they become facts for science only after they have -emerged therefrom. A man’s anxiety may be the anxiety -as directly felt by the man, or as thought of by him, or as -thought of by the general consensus of scientific observers. -But so also may be his body-temperature or weight or the -composition of the blood in his veins. There can be no -valid reason other than a pragmatic one for studying a -man’s anxiety solely as <i>felt</i> by him while studying his body-temperature -as <i>thought of</i> by him and others. And the -practical reasons are all in favor of studying all facts as they -exist for any impartial observer. A man’s mind as it is to -thinking men is all that thinking men can deal with and -all that they have any interest in dealing with.</p> - -<p>Finally, the subject-matter of psychology is not sharply -marked off from the subject-matter of physiology by being -absolutely non-spatial. On the contrary, the toothache, -anxiety and judgment are referred unequivocally, by every -sane man who thinks of them, to the space occupied by -the body of the individual in question. That is the surest -fact about them. It is true that we do not measure the -length, height, thickness and weight of an animal’s pain -or anxiety, but neither do we those of his pulse, temperature, -health, digestion, metabolism, patellar reflex or -heliotropism.</p> - -<p>Two noteworthy advantages are secured by the study -of behavior. First, the evidence about intellect and -character offered by action and the influence of intellect -and character upon action are given due attention. Second, -the connections of conscious states are studied as well as -their composition.</p> - -<p>The mind or soul of the older psychology was the cause -not only of consciousness, but also of modifiability in -thought and action. It was the substance or force in man<span class="pagenum"><a id="Page_15"></a>[15]</span> -whereby he was sensitive to certain events, was able to -make certain movements, and not only had ideas but connected -them one with another and with various impressions -and acts. It was supposed to account for actual bodily -action as well as for the action-consciousness. It explained -the connections between ideas as well as their internal -composition. If a modern psychologist defines mind as the -sum total of consciousness, and lives up to that definition, -he omits the larger portion of the task of his predecessors. -To define our subject-matter as the nature and behavior -of men, beginning where anatomy and physiology leave -off, is, on the contrary, to deliberately assume responsibility -for the entire heritage. Behavior includes consciousness -<i>and</i> action, states of mind <i>and</i> their connections.</p> - -<p>Even students devoted to ‘consciousness as such’ must -admit that the movements of an animal and their connections -with other features of his life deserve study, by even -their kind of psychologist. For the fundamental means -of knowing that an animal has a certain conscious state -are knowledge that it makes certain movements and knowledge -of what conscious states are connected with those -movements. Knowledge of the action-system of an animal -and its connections is a prerequisite to knowledge of its -stream of consciousness.</p> - -<p>There are better reasons for including the action-system -of an animal in the psychologist’s subject-matter. An -animal’s conscious stream is of no account to the rest of -the world except in so far as it prophesies or modifies his -action.<a id="FNanchor_2" href="#Footnote_2" class="fnanchor">[2]</a> There can be no moral warrant for studying -man’s nature unless the study will enable us to control -his acts. If a psychologist is to study man’s consciousness -without relation to movement, he might as well fabricate<span class="pagenum"><a id="Page_16"></a>[16]</span> -imaginary consciousnesses to describe and analyze. The -lovers of consciousness for its own sake often do this unwittingly, -but would scarcely take pride therein!</p> - -<p>The truth of the matter is, of course, that an animal’s -mind is, by any definition, something intimately associated -with his connection-system or means of binding various -physical activities to various physical impressions. The -whole series—external situations and motor responses as -well as their bonds—must be studied to some extent in -order to understand whatever we define as mind. The -student of behavior, by frankly accepting the task of supplying -any needed information not furnished by physiology, -and of studying the animal in action as well as in thought, -is surer of getting an adequate knowledge of whatever -features of an animal’s life may be finally awarded the title -of mind.</p> - -<p>The second advantage in studying total behavior rather -than consciousness as such is that thereby the connections -of mental facts one with another and with non-mental facts -receive due attention.</p> - -<p>The original tendencies to connect certain thoughts, -feelings and acts with certain situations—tendencies -which we call reflexes, instincts and capacities—are not -themselves states of consciousness; nor are the acquired -connections which we call habits, associations of ideas, -tendencies to attend, select and the like. No state of -consciousness bears within itself an account of when and -how it will appear, or of what bodily act will be its sequel. -What any given person will think in any given situation is -unpredictable by mere descriptions and analyses of his -previous thoughts each by itself. To understand the <i>when</i>, -<i>how</i> and <i>why</i> of states of consciousness one must study -other facts than states of consciousness. These non-conscious<span class="pagenum"><a id="Page_17"></a>[17]</span> -relations or connections, knowledge of which -informs us of the result to come from the action of a given -situation on a given animal, may be expected to be fully -half of the subject-matter of mental science.</p> - -<p>As was noted in the early pages of this chapter, the psychologist -commonly does adopt the attitude of treating mind -as a system of connections long enough to give some account -of the facts of instinct, habit, memory, and the like. But -the dogma that psychology deals exclusively with the inner -stream of mind-stuff has made these accounts needlessly -scanty and vague.</p> - -<p>One may appreciate fully the importance of finding out -whether the attention-consciousness is clearness or is something -else, and whether it exists in two or three discrete -degrees or in a continuous series of gradations, and still -insist upon the equal importance of finding out to what -facts and for what reasons human beings do attend. There -would appear, for example, to be an unfortunate limitation -to the study of human nature by the examination of its -consciousnesses, when two eminent psychologists, writing -elaborate accounts of attention from that point of view, -tell us almost nothing whereby we can predict what any -given animal will attend to in any given situation, or can -cause in any given animal a state of attention to any given -fact.</p> - -<p>One may enjoy the effort to define the kind of mind-stuff -in which one thinks of classes of facts, relations between -facts and judgments about facts, and still protest that a -proper balance in the study of intellect demands equal or -greater attention to the problems of why any given animal -thinks of any given fact, class or relation in any given -situation and why he makes this or that judgment about it.</p> - -<p>In the case of the so-called action-consciousness the<span class="pagenum"><a id="Page_18"></a>[18]</span> -neglect of the connections becomes preposterous. The -adventitious scraps of consciousness called ‘willing’ which -may intervene between a situation productive of a given -act and the act itself are hopelessly uninstructive in comparison -with the bonds of instinct and habit which cause the -situation to produce the act. In conduct, at least, that -kind of psychology which Santayana calls ‘the perception -of character’ seems an inevitable part of a well-balanced -science of human nature. I quote from his fine description -of the contrast between the external observation of a -mind’s connections and the introspective recapitulation of -its conscious content, though it is perhaps too pronounced -and too severe.</p> - -<p>“<i>Perception of Character.</i>—There is, however, a wholly -different and far more positive method of reading the mind, -or what in a metaphorical sense is called by that name. -This method is to read character. Any object with which -we are familiar teaches us to divine its habits; slight -indications, which we should be at a loss to enumerate -separately, betray what changes are going on and what -promptings are simmering in the organism.... The gift -of reading character ... is directed not upon consciousness -but upon past or eventual action. Habits and passions, -however, have metaphorical psychic names, names indicating -dispositions rather than particular acts (a disposition -being mythically represented as a sort of wakeful and haunting -genius waiting to whisper suggestions in a man’s ear). -We may accordingly delude ourselves into imagining that -a pose or a manner which really indicates habit indicates -feeling instead.</p> - -<p>“<i>Conduct Divined, Consciousness Ignored.</i>... As the -weather prophet reads the heavens, so the man of experience -reads other men. Nothing concerns him less than<span class="pagenum"><a id="Page_19"></a>[19]</span> -their consciousness; he can allow that to run itself off -when he is sure of their temper and habits. A great -master of affairs is usually unsympathetic. His observation -is not in the least dramatic or dreamful, he does -not yield himself to animal contagion or reënact other -people’s inward experience. He is too busy for that, -and too intent on his own purposes. His observation, -on the contrary, is straight calculation and inference, -and it sometimes reaches truths about people’s character -and destiny which they themselves are very far from -divining. Such apprehension is masterful and odious to -weaklings, who think they know themselves because they -indulge in copious soliloquy (which is the discourse of -brutes and madmen), but who really know nothing of -their own capacity, situation, or fate.”<a id="FNanchor_3" href="#Footnote_3" class="fnanchor">[3]</a></p> - -<p>Mr. Santayana elsewhere hints that both psychology and -history will become studies of human behavior considered -from without,—a part, that is, of what he calls physics,—if -they are to amount to much.</p> - -<p>Such a prediction may come true. But for the present -there is no need to decide which is better—to study an -animal’s self as conscious, its stream of direct experience, -or to study the intellectual and moral nature that causes its -behavior in thought and action and is known to many -observers. Since worthy men have studied both, both are -probably worthy of study. All that I wish to claim is the -right of a man of science to study an animal’s intellectual -and moral behavior, following wherever the facts lead—to -“the sum total of human experience considered as dependent -upon the experiencing person,” to the self as conscious, or to -a connection-system known to many observers and born -and bred in the animal’s body.</p> - -<hr class="chap x-ebookmaker-drop"> - -<div class="chapter"> - -<p><span class="pagenum"><a id="Page_20"></a>[20]</span></p> - -<h2 class="nobreak" id="CHAPTER_II">CHAPTER II<br> -<span class="smcap">Animal Intelligence; an Experimental Study of the -Associative Processes in Animals</span><a id="FNanchor_4" href="#Footnote_4" class="fnanchor">[4]</a></h2> - -</div> - -<p>This monograph is an attempt at an explanation of the -nature of the process of association in the animal mind. Inasmuch -as there have been no extended researches of a character -similar to the present one either in subject-matter or -experimental method, it is necessary to explain briefly its -standpoint.</p> - -<p>Our knowledge of the mental life of animals equals in -the main our knowledge of their sense-powers, of their -instincts or reactions performed without experience, and -of their reactions which are built up by experience. Confining -our attention to the latter, we find it the opinion of -the better observers and analysts that these reactions can -all be explained by the ordinary associative processes without -aid from abstract, conceptual, inferential thinking. -These associative processes then, as present in animals’ -minds and as displayed in their acts, are my subject-matter. -Any one familiar in even a general way with the literature -of comparative psychology will recall that this part of the -field has received faulty and unsuccessful treatment. The -careful, minute and solid knowledge of the sense-organs of -animals finds no counterpart in the realm of associations and -habits. We do not know how delicate or how complex or -how permanent are the possible associations of any given -group of animals. And although one would be rash who -said that our present equipment of facts about instincts<span class="pagenum"><a id="Page_21"></a>[21]</span> -was sufficient or that our theories about it were surely sound, -yet our notion of what occurs when a chick grabs a worm -are luminous and infallible compared to our notion of what -happens when a kitten runs into the house at the familiar -call. The reason that they have satisfied us as well as they -have is just that they are so vague. We say that the kitten -associates the sound ‘kitty kitty’ with the experience of -nice milk to drink, which does very well for a common-sense -answer. It also suffices as a rebuke to those who would -have the kitten ratiocinate about the matter, but it fails -to tell what real mental content is present. Does the kitten -feel “<i>sound of call, memory-image of milk in a saucer in the -kitchen, thought of running into the house, a feeling, finally, -of ‘I will run in’</i>”? Does he perhaps feel only the sound -of the bell and an impulse to run in, similar in quality to -the impulses which make a tennis player run to and fro -when playing? The word ‘association’ may cover a multitude -of essentially different processes, and when a writer -attributes anything that an animal may do to association, -his statement has only the negative value of eliminating -reasoning on the one hand and instinct on the other. -His position is like that of a zoölogist who should to-day -class an animal among the ‘worms.’ To give to the word a -positive value and several definite possibilities of meaning -is one aim of this investigation.</p> - -<p>The importance to comparative psychology in general of -a more scientific account of the association-process in animals -is evident. Apart from the desirability of knowing -all the facts we can, of whatever sort, there is the especial -consideration that these associations and consequent habits -have an immediate import for biological science. In the -higher animals the bodily life and preservative acts are -largely directed by these associations. They, and not<span class="pagenum"><a id="Page_22"></a>[22]</span> -instinct, make the animal use the best feeding grounds, -sleep in the same lair, avoid new dangers and profit by new -changes in nature. Their higher development in mammals -is a chief factor in the supremacy of that group. This, -however, is a minor consideration. The main purpose of -the study of the animal mind is to learn the development of -mental life down through the phylum, to trace in particular -the origin of human faculty. In relation to this chief purpose -of comparative psychology the associative processes -assume a rôle predominant over that of sense-powers or -instinct, for in a study of the associative processes lies the -solution of the problem. Sense-powers and instincts have -changed by addition and supersedence, but the cognitive -side of consciousness has changed not only in quantity but -also in quality. Somehow out of these associative processes -have arisen human consciousnesses with their sciences and -arts and religions. The association of ideas proper, imagination, -memory, abstraction, generalization, judgment, inference, -have here their source. And in the metamorphosis -the instincts, impulses, emotions and sense-impressions -have been transformed out of their old natures. For the -origin and development of human faculty we must look -to these processes of association in lower animals. Not -only then does this department need treatment more, but -promises to repay the worker better.</p> - -<p>Although no work done in this field is enough like the -present investigation to require an account of its results, -the <i>method</i> hitherto in use invites comparison by its contrast -and, as I believe, by its faults. In the first place, most of -the books do not give us a psychology, but rather a <i>eulogy</i>, -of animals. They have all been about animal <i>intelligence</i>, -never about animal <i>stupidity</i>. Though a writer derides -the notion that animals have reason, he hastens to add that<span class="pagenum"><a id="Page_23"></a>[23]</span> -they have marvelous capacity of forming associations, and -is likely to refer to the fact that human beings only rarely -reason anything out, that their trains of ideas are ruled -mostly by association, as if, in this latter, animals were on a -par with them. The history of books on animals’ minds -thus furnishes an illustration of the well-nigh universal tendency -in human nature to find the marvelous wherever it -can. We wonder that the stars are so big and so far apart, -that the microbes are so small and so thick together, and -for much the same reason wonder at the things animals -do. They used to be wonderful because of the mysterious, -God-given faculty of instinct, which could almost remove -mountains. More lately they have been wondered at because -of their marvelous mental powers in profiting by -experience. Now imagine an astronomer tremendously -eager to prove the stars as big as possible, or a bacteriologist -whose great scientific desire is to demonstrate the microbes -to be very, very little! Yet there has been a similar eagerness -on the part of many recent writers on animal psychology -to praise the abilities of animals. It cannot help leading to -partiality in deductions from facts and more especially in -the choice of facts for investigation. How can scientists -who write like lawyers, defending animals against the charge -of having no power of rationality, be at the same time -impartial judges on the bench? Unfortunately the real -work in this field has been done in this spirit. The level-headed -thinkers who might have won valuable results -have contented themselves with arguing against the theories -of the eulogists. They have not made investigations of -their own.</p> - -<p>In the second place, the facts have generally been derived -from anecdotes. Now quite apart from such pedantry as -insists that a man’s word about a scientific fact is worthless<span class="pagenum"><a id="Page_24"></a>[24]</span> -unless he is a trained scientist, there are really in this field -special objections to the acceptance of the testimony about -animals’ intelligent acts which one gets from anecdotes. -Such testimony is by no means on a par with testimony -about the size of a fish or the migration of birds, etc. For -here one has to deal not merely with ignorant or inaccurate -testimony, but also with prejudiced testimony. Human -folk are as a matter of fact eager to find intelligence in -animals. They like to. And when the animal observed is -a pet belonging to them or their friends, or when the story -is one that has been told as a story to entertain, further -complications are introduced. Nor is this all. Besides -commonly misstating what facts they report, they report -only such facts as show the animal at his best. Dogs get -lost hundreds of times and no one ever notices it or sends an -account of it to a scientific magazine. But let one find his -way from Brooklyn to Yonkers and the fact immediately -becomes a circulating anecdote. Thousands of cats on -thousands of occasions sit helplessly yowling, and no one -takes thought of it or writes to his friend, the professor; -but let one cat claw at the knob of a door supposedly as a -signal to be let out, and straightway this cat becomes the -representative of the cat-mind in all the books. The unconscious -distortion of the facts is almost harmless compared -to the unconscious neglect of an animal’s mental life -until it verges on the unusual and marvelous. It is as if -some denizen of a planet where communication was by -thought-transference, who was surveying humankind and -reporting their psychology, should be oblivious to all our -intercommunication save such as the psychical-research -society has noted. If he should further misinterpret the -cases of mere coincidence of thoughts as facts comparable -to telepathic communication, he would not be more wrong<span class="pagenum"><a id="Page_25"></a>[25]</span> -than some of the animal psychologists. In short, the -anecdotes give really the <i>abnormal</i> or <i>supernormal</i> psychology -of animals.</p> - -<p>Further, it must be confessed that these vices have been -only ameliorated, not obliterated, when the observation is -first-hand, is made by the psychologist himself. For as men -of the utmost scientific skill have failed to prove good -observers in the field of spiritualistic phenomena,<a id="FNanchor_5" href="#Footnote_5" class="fnanchor">[5]</a> so biologists -and psychologists before the pet terrier or hunted -fox often become like Samson shorn. They, too, have -looked for the intelligent and unusual and neglected the -stupid and normal.</p> - -<p>Finally, in all cases, whether of direct observation or -report by good observers or bad, there have been three other -defects. Only a single case is studied, and so the results -are not necessarily true of the type; the observation is not -repeated, nor are the conditions perfectly regulated; the -previous history of the animal in question is not known. -Such observations may tell us, if the observer is perfectly -reliable, that a certain thing takes place; but they cannot -assure us that it will take place universally among the animals -of that species, or universally with the same animal. -Nor can the influence of previous experience be estimated. -All this refers to means of getting knowledge about what -animals <i>do</i>. The next question is, “What do they <i>feel</i>?” -Previous work has not furnished an answer or the material -for an answer to this more important question. Nothing -but carefully designed, crucial experiments can. In abandoning<span class="pagenum"><a id="Page_26"></a>[26]</span> -the old method one ought to seek above all to -replace it by one which will not only tell more accurately -<i>what they do</i>, and give the much-needed information <i>how -they do it</i>, but also inform us <i>what they feel</i> while they act.</p> - -<p>To remedy these defects, experiment must be substituted -for observation and the collection of anecdotes. Thus you -immediately get rid of several of them. You can repeat the -conditions at will, so as to see whether or not the animal’s -behavior is due to mere coincidence. A number of animals -can be subjected to the same test, so as to attain typical -results. The animal may be put in situations where its -conduct is especially instructive. After considerable preliminary -observation of animals’ behavior under various -conditions, I chose for my general method one which, simple -as it is, possesses several other marked advantages besides -those which accompany experiment of any sort. It was -merely to put animals when hungry in inclosures from which -they could escape by some simple act, such as pulling at a -loop of cord, pressing a lever, or stepping on a platform. (A -detailed description of these boxes and pens will be given -later.) The animal was put in the inclosure, food was left -outside in sight, and his actions observed. Besides recording -his general behavior, special notice was taken of how he -succeeded in doing the necessary act (in case he did succeed), -and a record was kept of the time that he was in the box -before performing the successful pull, or clawing, or bite. -This was repeated until the animal had formed a perfect -association between the sense-impression of the interior of -that box and the impulse leading to the successful movement. -When the association was thus perfect, the time taken to -escape was, of course, practically constant and very short.</p> - -<p>If, on the other hand, after a certain time the animal did -not succeed, he was taken out, but <i>not fed</i>. If, after a sufficient<span class="pagenum"><a id="Page_27"></a>[27]</span> -number of trials, he failed to get out, the case was recorded -as one of complete failure. Enough different sorts -of methods of escape were tried to make it fairly sure that -association in general, not association of a particular sort of -impulse, was being studied. Enough animals were taken -with each box or pen to make it sure that the results were -not due to individual peculiarities. None of the animals -used had any previous acquaintance with any of the -mechanical contrivances by which the doors were opened. -So far as possible the animals were kept in a uniform state -of hunger, which was practically utter hunger.<a id="FNanchor_6" href="#Footnote_6" class="fnanchor">[6]</a> That is, -no cat or dog was experimented on, when the experiment -involved any important question of fact or theory,<span class="pagenum"><a id="Page_28"></a>[28]</span> -unless I was sure that his motive was of the standard -strength. With chicks this is not practicable, on account of -their delicacy. But with them dislike of loneliness acts as -a uniform motive to get back to the other chicks. Cats (or -rather kittens), dogs and chicks were the subjects of the -experiments. All were apparently in excellent health, save -an occasional chick.</p> - -<p>By this method of experimentation the animals are put -in situations which call into activity their mental functions -and permit them to be carefully observed. One may, by -following it, observe personally more intelligent acts than -are included in any anecdotal collection. And this actual -vision of animals in the act of using their minds is far more -fruitful than any amount of history of what animals have -done without the history of how they did it. But besides -affording this opportunity for purposeful and systematic -observation, our method is valuable because it frees the -animal from any influence of the observer. The animal’s -behavior is quite independent of any factors save its own -hunger, the mechanism of the box it is in, the food outside, -and such general matters as fatigue, indisposition, etc. -Therefore the work done by one investigator may be repeated -and verified or modified by another. No personal -factor is present save in the observation and interpretation. -Again, our method gives some very important results -which are quite uninfluenced by <i>any</i> personal factor in any -way. The curves showing the progress of the formation of -associations, which are obtained from the records of the -times taken by the animal in successive trials, are facts which -may be obtained by any observer who can tell time. They -are absolute, and whatever can be deduced from them is -sure. So also the question of whether an animal does or -does not form a certain association requires for an answer<span class="pagenum"><a id="Page_29"></a>[29]</span> -no higher qualification in the observer than a pair of eyes. -The literature of animal psychology shows so uniformly and -often so sadly the influence of the personal equation that -any method which can partially eliminate it deserves a trial.</p> - -<p>Furthermore, although the associations formed are such -as could not have been previously experienced or provided -for by heredity, they are still not too remote from the animal’s -ordinary course of life. They mean simply the connection -of a certain act with a certain situation and resultant -pleasure, and this general type of association is found -throughout the animal’s life normally. The muscular -movements required are all such as might often be required -of the animal. And yet it will be noted that the acts required -are nearly enough like the acts of the anecdotes to -enable one to compare the results of experiment by this -method with the work of the anecdote school. Finally, it -may be noticed that the method lends itself readily to experiments -on imitation.</p> - -<p>We may now start in with the description of the apparatus -and of the behavior of the animals.<a id="FNanchor_7" href="#Footnote_7" class="fnanchor">[7]</a></p> - -<h3><span class="smcap">Description of Apparatus</span></h3> - -<div class="figcenter illowp100" id="figure01" style="max-width: 31.25em;"> - <img class="w100" src="images/figure01.jpg" alt=""> - <p class="caption"><span class="smcap">Fig. 1.</span></p> -</div> - -<p>The shape and general apparatus of the boxes which were -used for the cats is shown by the accompanying drawing of -box K. Unless special figures are given, it should be understood -that each box is approximately 20 inches long, by 15 -broad, by 12 high. Except where mention is made to the -contrary, the door was pulled open by a weight attached to a<span class="pagenum"><a id="Page_30"></a>[30]</span> -string which ran over a pulley and was fastened to the door, -just as soon as the animal loosened the bolt or bar which -held it. Especial care was taken not to have the widest -openings between the bars at all near the lever, or wire -loop, or what not, which governed the bolt on the door. -For the animal instinctively attacks the large openings first, -and if the mechanism which governs the opening of the door -is situated near one of them, the animal’s task is rendered -easier. You do not then get the association-process so free -from the helping hand of instinct as you do if you make the -box without reference to the position of the mechanism to -be set up within it. These various mechanisms are so -simple that a verbal description will suffice in most cases. -The facts which the reader should note are the nature of the -movement which the cat had to make, the nature of the -object at which the movement was directed, and the position -of the object in the box. In some special cases attention<span class="pagenum"><a id="Page_31"></a>[31]</span> -will also be called to the force required. In general, -however, that was very slight (20 to 100 grams if applied -directly). The various boxes will be designated by capital -letters.</p> - -<p>A. A string attached to the bolt which held the door ran -up over a pulley on the front edge of the box, and was tied -to a wire loop (2½ inches in diameter) hanging 6 inches -above the floor in front center of box. Clawing or biting it, -or rubbing against it even, if in a certain way, opened the -door. We may call this box A ‘<i>O at front</i>.’</p> - -<p>B. A string attached to the bolt ran up over a pulley on -the front edge of the door, then across the box to another -pulley screwed into the inside of the back of the box 1¼ -inches below the top, and passing over it ended in a wire loop -(3 inches in diameter) 6 inches above the floor in back center -of box. Force applied to the loop or <i>to the string</i> as it ran -across the top of the box between two bars would open the -door. We may call B ‘<i>O at back</i>.’</p> - -<p>B1. In B1 the string ran outside the box, coming down -through a hole at the back, and was therefore inaccessible -and invisible from within. Only by pulling the loop could -the door be opened. B1 may be called ‘<i>O at back 2d</i>.’</p> - -<p>C. A door of the usual position and size (as in <a href="#figure01">Fig. 1</a>) was -kept closed by a wooden button 3½ inches long, ⅞ inch -wide, ½ inch thick. This turned on a nail driven into the -box ½ inch above the middle of the top edge of the door. -The door would fall inward as soon as the button was turned -from its vertical to a horizontal position. A pull of 125 -grams would do this if applied sideways at the lowest point -of the button 2¼ inches below its pivot. The cats usually -clawed the button round by downward pressure on its top -edge, which was 1¼ inches above the nail. Then, of course, -more force was necessary. C may be called ‘<i>Button</i>.’</p> - -<p><span class="pagenum"><a id="Page_32"></a>[32]</span></p> - -<p>D. The door was in the extreme right of the front. -A string fastened to the bolt which held it ran up -over a pulley on the top edge and back to the top edge -of the back side of the box (3 inches in from the right -side) and was there firmly fastened. The top of the box -was of wire screening and arched over the string ¾ inch -above it along its entire length. A slight pull on the -string anywhere opened the door. This box was 20 × 16, -but a space 7 × 16 was partitioned off at the left by a wire -screen. D may be called ‘<i>String</i>.’</p> - -<p>D1 was the same box as B, but had the string fastened -firmly at the back instead of running over a pulley and -ending in a wire loop. We may call it ‘<i>String 2d</i>.’</p> - -<p>E. A string ran from the bolt holding the door up over a -pulley and down to the floor outside the box, where it was -fastened 2 inches in front of the box and 1½ inches to the -left of the door (looking from the inside). By poking a paw -out between the bars and pulling this string inward the door -would be opened. We may call E ‘<i>String outside</i>.’</p> - -<p>In F the string was not fastened to the floor but ended in a -loop 2½ inches in diameter which could be clawed down so as -to open the door. Unless the pull was in just the right direction, -the string was likely to catch on the pulley. This loop -hung 3 inches above the floor, and 1¾ inches in front of the -box. We may call F ‘<i>String outside unfastened</i>.’</p> - -<p>G was a box 29 × 20½ × 22½, with a door 29 × 12 hinged -on the left side of the box (looking from within), and kept -closed by an ordinary thumb latch placed 15 inches from -the floor. The remainder of the front of the box was closed -in by wooden bars. The door was a wooden frame covered -with screening. It was <i>not</i> arranged so as to open as soon as -the latch was lifted, but required a force of 400 grams, even -when applied to the best advantage. The bar of the thumb<span class="pagenum"><a id="Page_33"></a>[33]</span> -latch, moreover, would fall back into place again unless the -door were pushed out at least a little. The top of this box -was not of bars or screening, but solid. We may call G -‘<i>Thumb latch</i>.’</p> - -<p>H was, except for the opening where the door was situated, -a perfectly solid and dark box. In the front was cut an -opening about 9 × 7 inches. A wooden frame covered with -wire netting hung in front of this. It was fastened to the -box only by a screw through the middle of the frame’s top -piece, and could therefore be pushed to either side so as to -permit escape from the box if it were prevented from swinging -back into place.</p> - -<p>I was a box 12 × 14 × 23. The door was 8 inches wide, 4 -high, and hinged at the left side. It was held closed by a -wooden bar which moved easily on a pivot and which could -be pushed up by another bar which projected 5 inches into -the box. This second bar was pivoted so that downward -pressure on it pushed the first bar up and let the door swing -open. The second bar entered the box at a point 4 inches -above the floor and 2½ inches in from the right side of the -box. In its normal position its inner end was 5½ inches -above the floor. A depression of 2 inches at that end was -necessary to open the door. Of course, nearer the pivot a -shorter depression would do. The front of the box was -closed by bars, but the rest by solid boards. We may call I -‘<i>Lever</i>.’</p> - -<p>J was the same as B except that the door was not opened -by a weight as soon as the bolt was pulled up. On the contrary, -the door was held closed by a small piece of board -(4 × 3½ × ¾ thick) placed against it outside. After -pulling the loop at the back the cat had to knock down -this support and push the door open. We may call J -‘<i>Double</i>.’</p> - -<p><span class="pagenum"><a id="Page_34"></a>[34]</span></p> - -<p>K was a box arranged so that three separate acts were required -to open the door, which was held by two bolts at the -top and two bars outside. One of the bolts was connected -with a platform in the back center of the box so that depressing -the platform raised the bolt. The other was raised by a -string which ran up over a pulley in the front, across the -box 1 inch above the bars, over a pulley near the corner of -the box, and down to the floor, where it was fastened. Pulling -on this string, either by clawing at it where it was running -vertically from the last pulley to the floor, or by putting -the paw out between the bars which covered the top of the -box, and clawing the string downward, would raise the bolt. -If both bolts were raised and <i>either</i> bar was pushed up or -down far enough to be out of the way, the cat could escape. -K, or ‘<i>Triple</i>,’ as it may be called, is the box reproduced in -<a href="#figure01">Figure 1</a>.</p> - -<p>L was a box that also required three acts to open the door. -It was a combination of A (O at front), D (string), I (lever). -The lever or bar to be depressed was 2 inches to the right of -the door, which was in the front center. The string to be -clawed or bitten ran from front center to back center 1 inch -below the top of the box.</p> - -<p>Z was a box with back and sides entirely closed, with -front and top closed by bars and screening, with a small -opening in the left-hand corner. A box was held in front -of this and drawn away when the cats happened to lick -themselves. Thus escape and food followed always upon -the impulse to lick themselves, and they soon would immediately -start doing so as soon as pushed into the box. -The same box was used with the impulse changed to that -for scratching themselves. The size of this box was -15 × 10 × 16.</p> - -<p><span class="pagenum"><a id="Page_35"></a>[35]</span></p> - -<h3><span class="smcap">Experiments with Cats</span></h3> - -<p>In these various boxes were put cats from among the -following. I give approximately their ages while under -experiment.</p> - -<ul> -<li>No. 1. 8-10 months.</li> -<li>No. 2. 5-7 months.</li> -<li>No. 3. 5-11 months.</li> -<li>No. 4. 5-8 months.</li> -<li>No. 5. 5-7 months.</li> -<li>No. 6. 3-5 months.</li> -<li>No. 7. 3-5 months.</li> -<li>No. 8. 6-6½ months.</li> -<li>No. 10. 4-8 months.</li> -<li>No. 11. 7-8 months.</li> -<li>No. 12. 4-6 months.</li> -<li>No. 13. 18-19 months.</li> -</ul> - -<p>The behavior of all but 11 and 13 was practically the same. -When put into the box the cat would show evident signs of -discomfort and of an impulse to escape from confinement. -It tries to squeeze through any opening; it claws and bites -at the bars or wire; it thrusts its paws out through any -opening and claws at everything it reaches; it continues its -efforts when it strikes anything loose and shaky; it may -claw at things within the box. It does not pay very much -attention to the food outside, but seems simply to strive -instinctively to escape from confinement. The vigor with -which it struggles is extraordinary. For eight or ten -minutes it will claw and bite and squeeze incessantly. -With 13, an old cat, and 11, an uncommonly sluggish cat, -the behavior was different. They did not struggle vigorously -or continually. On some occasions they did not even -struggle at all. It was therefore necessary to let them out -of some box a few times, feeding them each time. After -they thus associate climbing out of the box with getting -food, they will try to get out whenever put in. They do not, -even then, struggle so vigorously or get so excited as the -rest. In either case, whether the impulse to struggle be<span class="pagenum"><a id="Page_36"></a>[36]</span> -due to an instinctive reaction to confinement or to an association, -it is likely to succeed in letting the cat out of the -box. The cat that is clawing all over the box in her impulsive -struggle will probably claw the string or loop or button -so as to open the door. And gradually all the other non-successful -impulses will be stamped out and the particular -impulse leading to the successful act will be stamped in by -the resulting pleasure, until, after many trials, the cat will, -when put in the box, immediately claw the button or loop -in a definite way.</p> - -<p>The starting point for the formation of any association -in these cases, then, is the set of instinctive activities which -are aroused when a cat feels discomfort in the box either -because of confinement or a desire for food. This discomfort, -plus the sense-impression of a surrounding, confining -wall, expresses itself, prior to any experience, in squeezings, -clawings, bitings, etc. From among these movements one -is selected by success. But this is the starting point only -in the case of the first box experienced. After that the cat -has associated with the feeling of confinement certain impulses -which have led to success more than others and are -thereby strengthened. A cat that has learned to escape -from A by clawing has, when put into C or G, a greater tendency -to claw at things than it instinctively had at the start, -and a less tendency to squeeze through holes. A very -pleasant form of this decrease in instinctive impulses was -noticed in the gradual cessation of howling and mewing. -However, the useless instinctive impulses die out slowly, -and often play an important part even after the cat has had -experience with six or eight boxes. And what is important -in our previous statement, namely, that the activity of an -animal when first put into a new box is not directed by any -appreciation of <i>that</i> box’s character, but by certain general<span class="pagenum"><a id="Page_37"></a>[37]</span> -impulses to act, is not affected by this modification. Most -of this activity is determined by heredity; some of it, by -previous experience.</p> - -<p>My use of the words <i>instinctive</i> and <i>impulse</i> may cause -some misunderstanding unless explained here. Let us, -throughout this book, understand by instinct any reaction -which an animal makes to a situation <i>without experience</i>. -It thus includes unconscious as well as conscious acts. -Any reaction, then, to totally new phenomena, when first -experienced, will be called instinctive. Any impulse then -felt will be called an instinctive impulse. Instincts include -whatever the nervous system of an animal, as far as inherited, -is capable of. My use of the word will, I hope, everywhere -make clear what fact I mean. If the reader gets the -fact meant in mind it does not in the least matter whether -he would himself call such a fact instinct or not. Any -one who objects to the word may substitute ‘hocus-pocus’ -for it wherever it occurs. The definition here made will not -be used to prove or disprove any theory, but simply as a -signal for the reader to imagine a certain sort of fact.</p> - -<p>The word <i>impulse</i> is used against the writer’s will, but -there is no better. Its meaning will probably become clear -as the reader finds it in actual use, but to avoid misconception -at any time I will state now that <i>impulse</i> means the -consciousness accompanying a muscular innervation <i>apart -from that feeling of the act which comes from seeing oneself -move, from feeling one’s body in a different position, etc.</i> It -is the <i>direct feeling of the doing</i> as distinguished from the -<i>idea of the act done</i> gained through eye, etc. For this -reason I say ‘impulse <i>and</i> act’ instead of simply ‘act.’ -Above all, it must be borne in mind that by impulse I never -mean the <i>motive</i> to the act. In popular speech you may say -that hunger is the impulse which makes the cat claw. That<span class="pagenum"><a id="Page_38"></a>[38]</span> -will never be the use here. The word <i>motive</i> will always -denote that sort of consciousness. Any one who thinks -that the act ought not to be thus subdivided into impulse -and deed may feel free to use the word <i>act</i> for <i>impulse</i> or <i>impulse -and act</i> throughout, if he will remember that the act -in this aspect of being felt as to be done or as doing is in -animals the important thing, is the thing which gets associated, -while the act as done, as viewed from outside, is a -secondary affair. I prefer to have a separate word, <i>impulse</i>, -for the former, and keep the word <i>act</i> for the latter, which it -commonly means.</p> - -<p>Starting, then, with its store of instinctive impulses, -the cat hits upon the successful movement, and gradually -associates it with the sense-impression of the interior of the -box until the connection is perfect, so that it performs the -act as soon as confronted with the sense-impression. The -formation of each association may be represented graphically -by a time-curve. In these curves lengths of one millimeter -along the abscissa represent successive experiences -in the box, and heights of one millimeter above it each -represent ten seconds of time. The curve is formed by -joining the tops of perpendiculars erected along the abscissa -1 mm. apart (the first perpendicular coinciding with the <i>y</i> -line), each perpendicular representing the time the cat was -in the box before escaping. Thus, in <a href="#figure02">Fig. 2 on page 39</a> the -curve marked <i>12 in A</i> shows that, in 24 experiences or -trials in box A, cat 12 took the following times to perform -the act, 160 sec., 30 sec., 90 sec., 60, 15, 28, 20, 30, 22, 11, 15, -20, 12, 10, 14, 10, 8, 8, 5, 10, 8, 6, 6, 7. A short vertical line -below the abscissa denotes that an interval of approximately -24 hours elapsed before the next trial. Where the interval -was longer it is designated by a figure 2 for two days, 3 for -three days, etc. If the interval was shorter, the number of -hours is specified by 1 hr., 2 hrs., etc. In many cases the -animal failed in some trial to perform the act in ten or -fifteen minutes and was then taken out by me. Such failures -are denoted by a break in the curve either at its start -or along its course. In some cases there are short curves -after the main ones. These, as shown by the figures beneath, -represent the animal’s mastery of the association -after a very long interval of time, and may be called memory-curves. -A discussion of them will come in the last part of -the chapter.</p> - -<p><span class="pagenum"><a id="Page_39"></a>[39]</span></p> - -<div class="figcenter illowp48" id="figure02" style="max-width: 28.125em;"> - <img class="w100" src="images/figure02.jpg" alt=""> - <p class="caption"><span class="smcap">Fig. 2.</span></p> -</div> - -<p><span class="pagenum"><a id="Page_40"></a>[40]</span></p> - -<p>The time-curve is obviously a fair representation of the -progress of the formation of the association, for the two -essential factors in the latter are the disappearance of all -activity save the particular sort which brings success with -it, and perfection of that particular sort of act so that it is -done precisely and at will. Of these the second is, on deeper -analysis, found to be a part of the first; any clawing at a -loop except the particular claw which depresses it is theoretically -a useless activity. If we stick to the looser phraseology, -however, no harm will be done. The combination of these -two factors is inversely proportional to the time taken, -provided the animal surely wants to get out at once. This -was rendered almost certain by the degree of hunger. -Theoretically a perfect association is formed when both -factors are perfect,—when the animal, for example, does -nothing but claw at the loop, and claws at it in the most -useful way for the purpose. In some cases (<i>e.g.</i> 2 in K on -<a href="#Page_53">page 53</a>) neither factor ever gets perfected in a great many -trials. In some cases the first factor does but the second -does not, and the cat goes at the thing not always in the -desirable way. In all cases there is a fraction of the time -which represents getting oneself together after being -dropped in the box, and realizing where one is. But for -our purpose all these matters count little, and we may take -the general slope of the curve as representing very fairly -the progress of the association. The slope of any particular -part of it may be due to accident. Thus, very often the -second experience may have a higher time-point than the -first, because the first few successes may all be entirely -due to accidentally hitting the loop, or whatever it is, and -whether the accident will happen sooner in one trial than -another is then a matter of chance. Considering the general -slope, it is, of course, apparent that a gradual descent—say, -from initial times of 300 sec. to a constant time of 6 or 8 sec. -in the course of 20 to 30 trials—represents a difficult -association; while an abrupt descent, say in 5 trials, from a -similar initial height, represents a very easy association. -Thus, 2 in Z, on <a href="#Page_57">page 57</a>, is a hard, and 1 in I, on <a href="#Page_49">page 49</a>, -an easy association.</p> - -<p><span class="pagenum"><a id="Page_41"></a>[41]</span></p> - -<div class="figcenter illowp48" id="figure03" style="max-width: 28.125em;"> - <img class="w100" src="images/figure03.jpg" alt=""> - <p class="caption"><span class="smcap">Fig. 3.</span></p> -</div> - -<p><span class="pagenum"><a id="Page_42"></a>[42]</span></p> - -<p>In boxes A, C, D, E, I, 100 per cent of the cats given a -chance to do so, hit upon the movement and formed the -association. The following table shows the results where -some cats failed:—</p> - -<h4><span class="smcap">Table 1</span></h4> - -<table> - <tr> - <th></th> - <th><span class="smcap">No. Cats<br>Tried</span></th> - <th><span class="smcap">No. Cats<br>Failed</span></th> - </tr> - <tr> - <td class="tdc">F</td> - <td class="tdc bl bt">5</td> - <td class="tdc bl br bt">4</td> - </tr> - <tr> - <td class="tdc">G</td> - <td class="tdc bl">8</td> - <td class="tdc bl br">5</td> - </tr> - <tr> - <td class="tdc">H</td> - <td class="tdc bl">9</td> - <td class="tdc bl br">2</td> - </tr> - <tr> - <td class="tdc">J</td> - <td class="tdc bl">5</td> - <td class="tdc bl br">2</td> - </tr> - <tr> - <td class="tdc">K</td> - <td class="tdc bl bb">5</td> - <td class="tdc bl br bb">2</td> - </tr> -</table> - -<p>The time-curves follow. By referring to the description -of apparatus they will be easily understood. Each mm. -along the abscissa represents one trial. Each mm. above -it represents 10 seconds.</p> - -<p><span class="pagenum"><a id="Page_43"></a>[43]</span></p> - -<div class="figcenter illowp48" id="figure04" style="max-width: 28.125em;"> - <img class="w100" src="images/figure04.jpg" alt=""> - <p class="caption"><span class="smcap">Fig. 4.</span></p> -</div> - -<p><span class="pagenum"><a id="Page_44"></a>[44]</span></p> - -<div class="figcenter illowp95" id="figure05" style="max-width: 31.25em;"> - <img class="w100" src="images/figure05.jpg" alt=""> - <p class="caption"><span class="smcap">Fig. 5.</span></p> -</div> - -<p>These time-curves show, in the first place, what associations -are easy for an animal to form, and what are hard. -The act must be one which the animal will perform in the -course of the activity which its inherited equipment incites -or its previous experience has connected with the sense-impression -of a box’s interior. The oftener the act naturally -occurs in the course of such activity, the sooner it -will be performed in the first trial or so, and this is one condition, -sometimes, of the ease of forming the association. -For if the first few successes are five minutes apart, the -influence of one may nearly wear off before the next, while -if they are forty seconds apart the influences may get summated. -But this is not the only or the main condition of -the celerity with which an association may be formed. It -depends also on the amount of attention given to the act. -An act of the sort likely to be well attended to will be learned -more quickly. Here, too, accident may play a part, for a -cat may merely happen to be attending to its paw when it -claws. The kind of acts which insure attention are those -where the movement which works the mechanism is one -which the cat makes definitely to get out. Thus A (O at -front) is easier to learn than C (button), because the cat -does A in trying to claw down the front of the box and so -is attending to what it does; whereas it does C generally -in a vague scramble along the front or while trying to claw -outside with the other paw, and so does not attend to the -little unimportant part of its act which turns the button -round. Above all, <i>simplicity</i> and <i>definiteness</i> in the act -make the association easy. G (thumb latch), J (double) -and K and L (triples) are hard, because complex. E is -easy, because directly in the line of the instinctive impulse -to try to pull oneself out of the box by clawing at -anything outside. It is thus very closely attended to. -The extreme of ease is reached when a single experience -stamps the association in so completely that ever after the -act is done at once. This is approached in I and E.</p> - -<p><span class="pagenum"><a id="Page_45"></a>[45]</span></p> - -<div class="figcenter illowp48" id="figure06" style="max-width: 28.125em;"> - <img class="w100" src="images/figure06.jpg" alt=""> - <p class="caption"><span class="smcap">Fig. 6.</span></p> -</div> - -<p><span class="pagenum"><a id="Page_46"></a>[46]</span></p> - -<p>In these experiments the sense-impressions offered no -difficulty one more than the other.</p> - -<p>Vigor, abundance of movements, was observed to make -differences between individuals in the same association. -It works by shortening the first times, the times when the -cat still does the act largely by accident. Nos. 3 and 4 -show this throughout. Attention, often correlated with lack -of vigor, makes a cat form an association more quickly after -he gets started. No. 13 shows this somewhat. The absence -of a fury of activity let him be more conscious of what -he did do.</p> - -<p><span class="pagenum"><a id="Page_47"></a>[47]</span></p> - -<div class="figcenter illowp48" id="figure07" style="max-width: 28.125em;"> - <img class="w100" src="images/figure07.jpg" alt=""> - <p class="caption"><span class="smcap">Fig. 7.</span></p> -</div> - -<p><span class="pagenum"><a id="Page_48"></a>[48]</span></p> - -<p>The curves on <a href="#Page_57">pages 57 and 58</a>, showing the history of -cats 1, 5, 13 and 3, which were let out of the box Z when -they licked themselves, and of cats 6, 2 and 4, which were -let out when they scratched themselves, are interesting because -they show associations where there is no congruity -(no more to a cat than to a man) between the act and the -result. One chick, too, was thus freed whenever he pecked -at his feathers to dress them. He formed the association, -and would whirl his head round and poke it into his feathers -as soon as dropped in the box. There is in all these cases -a noticeable tendency, of the cause of which I am ignorant, -to diminish the act until it becomes a mere vestige of a -lick or scratch. After the cat gets so that it performs the -act soon after being put in, it begins to do it less and less -vigorously. The licking degenerates into a mere quick -turn of the head with one or two motions up and down with -tongue extended. Instead of a hearty scratch, the cat -waves its paw up and down rapidly for an instant. Moreover, -if sometimes you do not let the cat out after this -feeble reaction, it does not at once repeat the movement, -as it would do if it depressed a thumb piece, for instance, -without success in getting the door open. Of the reason for -this difference I am again ignorant.</p> - -<p>Previous experience makes a difference in the quickness -with which the cat forms the associations. After getting -out of six or eight boxes by different sorts of acts the cat’s -general tendency to claw at loose objects within the box is -strengthened and its tendency to squeeze through holes -and bite bars is weakened; accordingly it will learn associations -along the general line of the old more quickly. Further, -its tendency to pay attention to what it is doing gets -strengthened, and this is something which may properly -be called a change in degree of intelligence. A test was -made of the influence of experience in this latter way by -putting two groups of cats through I (lever), one group -(1, 2, 3, 4, 5) after considerable experience, the other (10, -11, 12) after experience with only one box. As the act in I -was not along the line of the acts in previous boxes, and as -a decrease in the squeezings and bitings would be of little -use in the box as arranged, the influence of experience in -the former way was of little account. The curves of all -are shown on <a href="#Page_49">page 49</a>.</p> - -<p><span class="pagenum"><a id="Page_49"></a>[49]</span></p> - -<div class="figcenter illowp48" id="figure08" style="max-width: 28.125em;"> - <img class="w100" src="images/figure08.jpg" alt=""> - <p class="caption"><span class="smcap">Fig. 8.</span></p> -</div> - -<p><span class="pagenum"><a id="Page_50"></a>[50]</span></p> - -<p>If the whole set of curves are examined in connection with -the following table, which gives the general order in which -each animal took up the different associations which he -eventually formed, many suggestions of the influence of -experience will be met with. The results are not exhaustive -enough to justify more than the general conclusion that -there is such an influence. By taking more individuals -and thus eliminating all other factors besides experience, -one can easily show just how and how far experience facilitates -association.</p> - -<p>When, in this table, the letters designating the boxes are -in italics it means that, though the cat formed the association, -it was in connection with other experiments and so is -not recorded in the curves.</p> - -<h4><span class="smcap">Table 2</span></h4> - -<table class="borders"> - <tr> - <td class="bl bt">Cat 1</td> - <td class="bt"><i>A</i> <i>B</i> <i>C</i> <i>D₁</i> <i>D</i> Z I</td> - </tr> - <tr> - <td class="bl">Cat 2</td> - <td><i>C</i> <i>D₁</i> <i>D</i> E Z H J I K</td> - </tr> - <tr> - <td class="bl">Cat 3</td> - <td>A C E G H J Z I K</td> - </tr> - <tr> - <td class="bl">Cat 4</td> - <td>C F G D Z H J I K</td> - </tr> - <tr> - <td class="bl">Cat 5</td> - <td>C E Z H I</td> - </tr> - <tr> - <td class="bl">Cat 6</td> - <td><i>A</i> <i>C</i> E Z</td> - </tr> - <tr> - <td class="bl">Cat 7</td> - <td><i>A</i> <i>C</i></td> - </tr> - <tr> - <td class="bl">Cat 10</td> - <td>C I A H D L</td> - </tr> - <tr> - <td class="bl">Cat 11</td> - <td>C I A H D L</td> - </tr> - <tr> - <td class="bl">Cat 12</td> - <td>C I A H D L</td> - </tr> - <tr> - <td class="bl bb br">Cat 13</td> - <td class="bb">A C D G Z</td> - </tr> -</table> - -<p><span class="pagenum"><a id="Page_51"></a>[51]</span></p> - -<div class="figcenter illowp48" id="figure09" style="max-width: 28.125em;"> - <img class="w100" src="images/figure09.jpg" alt=""> - <p class="caption"><span class="smcap">Fig. 9.</span></p> -</div> - -<p><span class="pagenum"><a id="Page_52"></a>[52]</span></p> - -<p>The advantage due to experience in our experiments is -not, however, the same as ordinarily in the case of trained -animals. With them the associations are with the acts or -voice of man or with sense-impressions to which they naturally -do not attend (<i>e.g.</i> figures on a blackboard, ringing of -a bell, some act of another animal). Here the advantage -of experience is mainly due to the fact that by such experience -the animals gain the habit of attending to the -master’s face and voice and acts and to sense-impressions -in general.</p> - -<p>I made no attempt to find the differences in ability to -acquire associations due to age or sex or fatigue or circumstances -of any sort. By simply finding the average slope -in the different cases to be compared, one can easily demonstrate -any such differences that exist. So far as this discovery -is profitable, investigation along this line ought now -to go on without delay, the method being made clear. -Of differences due to differences in the species, genus, etc., -of the animals I will speak after reviewing the time-curves -of dogs and chicks.</p> - -<p>In the present state of animal psychology there is another -value to these results which was especially aimed at by the investigator -from the start. They furnish a quantitative estimate -of what the average cat can do, so that if any one has an -animal which he thinks has shown superior intelligence or -perhaps reasoning power, he may test his observations and -opinion by taking the time-curves of the animal in such -boxes as I have described.</p> - -<p><span class="pagenum"><a id="Page_53"></a>[53]</span></p> - -<div class="figcenter illowp48" id="figure10" style="max-width: 28.125em;"> - <img class="w100" src="images/figure10.jpg" alt=""> - <p class="caption"><span class="smcap">Fig. 10.</span></p> -</div> - -<p><span class="pagenum"><a id="Page_54"></a>[54]</span></p> - -<p>If his animal in a number of cases forms the associations -very much more quickly, or deals with the situation in a -more intelligent fashion than my cats did, then he may have -ground for claiming in his individual a variation toward -greater intelligence and, possibly, intelligence of a different -order. On the other hand, if the animal fails to rise above -the type in his dealings with the boxes, the observer should -confess that his opinion of the animal’s intelligence may -have been at fault and should look for a correction of it.</p> - -<p>We have in these time-curves a fairly adequate measure -of what the ordinary cat can do, and how it does it, and in -similar curves soon to be presented a less adequate measure -of what a dog may do. If other investigators, especially -all amateurs who are interested in animal intelligence, will -take other cats and dogs, especially those supposed by owners -to be extraordinarily intelligent, and experiment with -them in this way, we shall soon get a notion of how much -variation there is among animals in the direction of more or -superior intelligence. The beginning here made is meager -but solid. The knowledge it gives needs to be much extended. -The variations found in individuals should be -correlated, not merely with supposed superiority in intelligence, -a factor too vague to be very serviceable, but with -observed differences in vigor, attention, memory and muscular -skill. No phenomena are more capable of exact and -thorough investigation by experiment than the associations -of animal consciousness. Never will you get a better -psychological subject than a hungry cat. When the crude -beginnings of this research have been improved and replaced -by more ingenious and adroit experimenters, the -results ought to be very valuable.</p> - -<p>Surely every one must agree that no man now has a right -to advance theories about what is in animals’ minds or to -deny previous theories unless he supports his thesis by -systematic and extended experiments. My own theories, -soon to be proclaimed, will doubtless be opposed by many. -I sincerely hope they will, provided the denial is accompanied -by actual experimental work. In fact, I shall be tempted -again and again in the course of this book to defend some -theory, dubious enough to my own mind, in the hope of -thereby inducing some one to oppose me and in opposing -me to make the experiments I have myself had no opportunity -to make yet. Probably there will be enough opposition -if I confine myself to the theories I feel sure of.</p> - -<p><span class="pagenum"><a id="Page_55"></a>[55]</span></p> - -<div class="figcenter illowp48" id="figure11" style="max-width: 28.125em;"> - <img class="w100" src="images/figure11.jpg" alt=""> - <p class="caption"><span class="smcap">Fig. 11.</span></p> -</div> - -<p><span class="pagenum"><a id="Page_56"></a>[56]</span></p> - -<h3><span class="smcap">Experiments with Dogs</span></h3> - -<p>The boxes used were as follows:</p> - -<p>AA was similar to A (O at front), except that the loop was -of stiff cord ⅜ inch in diameter and was larger (3½ inches -diameter); also it was hung a foot from the floor and 8 -inches to the right of the door. The box itself was 41 × 20 -× 23.</p> - -<p>BB was similar to B, the loop being the same as in AA, -and being hung a foot from the floor. The box was of the -same size and shape as AA.</p> - -<p>BB1 was like BB, but the loop was hung 18 inches from -the floor.</p> - -<p>CC was similar to C (button), but the button was 6 -inches long, and the box was 36½ × 22 × 23.</p> - -<p>II was similar to I, but the box was 30 × 20 × 25 inches; -the door (11 inches wide, 6 high) was in the left front corner, -and the lever was 6 inches long and entered the box at a -point 2 inches to the right of the door and 4 inches above -the floor.</p> - -<p><span class="pagenum"><a id="Page_57"></a>[57]</span></p> - -<div class="figcenter illowp48" id="figure12" style="max-width: 28.125em;"> - <img class="w100" src="images/figure12.jpg" alt=""> - <p class="caption"><span class="smcap">Fig. 12.</span></p> -</div> - -<p><span class="pagenum"><a id="Page_58"></a>[58]</span></p> - -<p>In M the same box as in II was used, but instead of a -lever projecting inside the box, a lever running outside -parallel to the plane of the front of the box and 18 inches -long was used. This lay close against the bars composing -the front of the box, and could be pawed down by -sticking the paw out an inch or so between two bars, at -a point about 15 inches high and 6 inches in from the -right edge of the front. We may call M ‘<i>Lever outside</i>.’</p> - -<div class="figcenter illowp48" id="figure13" style="max-width: 28.125em;"> - <img class="w100" src="images/figure13.jpg" alt=""> - <p class="caption"><span class="smcap">Fig. 13.</span></p> -</div> - -<p>N was a pen 5 × 3 feet made of wire netting 46 inches -high. The door, 31 × 20, was in the right half of the front. -A string from the bolt passed up over a pulley and back to -the back center, where it was fastened 33 inches above the -floor. Biting or pawing this string opened the door.</p> - -<p><span class="pagenum"><a id="Page_59"></a>[59]</span></p> - -<p>O was like K, except that there was only one bar, that -the string ran inside the box, so that it was easily accessible, -and that the bolt raised in K by depression of the platform -could be raised in O (and was by the dog experimented on) -by sticking the muzzle out between two bars just above -the bolt and by biting the string, at the same time jerking -it upward. O was 30 × 20 × 25 in size.</p> - -<p>The box G was used for both dogs and cats, without any -variation save that for dogs the resistance of the door to -pressure outwards was doubled.</p> - -<p>In these boxes were put in the course of the experiments -dog 1 (about 8 months old), and dogs 2 and 3, adults, all -of small size.</p> - -<p>A dog who, when hungry, is shut up in one of these boxes -is not nearly so vigorous in his struggles to get out as is the -young cat. And even after he has experienced the pleasure -of eating on escape many times he does not try to get out -so hard as a cat, young or old. He does try to a certain -extent. He paws or bites the bars or screening, and tries -to squeeze out in a tame sort of way. He gives up his -attempts sooner than the cat, if they prove unsuccessful. -Furthermore his attention is taken by the food, not the -confinement. He wants to get <i>to</i> the food, not <i>out of</i> the -box. So, unlike the cat, he confines his efforts to the front -of the box. It was also a practical necessity that the dogs -should be kept from howling in the evening, and for this -reason I could not use as motive the utter hunger which -the cats were made to suffer. In the morning, when the -experiments were made, the dogs were surely hungry, -and no experiment is recorded in which the dog was not -in a state to be willing to make a great effort for a bit of -meat, but the motive may not have been even and equal -throughout, as it was with the cats.</p> - -<p><span class="pagenum"><a id="Page_60"></a>[60]</span></p> - -<div class="figcenter illowp48" id="figure14" style="max-width: 28.125em;"> - <img class="w100" src="images/figure14.jpg" alt=""> - <p class="caption"><span class="smcap">Fig. 14.</span></p> -</div> - -<p><span class="pagenum"><a id="Page_61"></a>[61]</span></p> - -<p>The curves on <a href="#Page_60">page 60</a> are to be interpreted in the same -way as those for the cats, and are on the same scale. The -order in which No. 1 took up the various associations was -AA, BB, BB1, G, N, CC, II, O.</p> - -<p>The percentage of dogs succeeding in the various boxes -is given below, but is of no consequence, because so few -were tried, and because the motive, hunger, was not perhaps -strong enough, or equal in all cases.</p> - -<p>In AA 3 out of 3.</p> - -<p>In BB 0 out of 2 (that is, without previous experience -of AA).</p> - -<p>In CC 1 out of 2.</p> - -<p>In II 3 out of 3.</p> - -<p>In M 1 out of 2.</p> - -<p>In N 1 out of 3.</p> - -<p>In G 1 out of 3.</p> - -<h3><span class="smcap">Experiments with Chicks</span></h3> - -<p>The apparatus was as follows:</p> - -<div class="figcenter illowp100" id="figure15-17" style="max-width: 31.25em;"> - <img class="w100" src="images/figure15-17.jpg" alt=""> - <p class="caption"><span class="smcap">Fig. 15.</span> <span class="smcap">Fig. 16.</span> <span class="smcap">Fig. 17.</span></p> -</div> - -<p>P was simply a small pen arranged with two exits, one -leading to the inclosure where were the other chicks and -food, one leading to another pen with no exit. The drawing -(<a href="#figure15-17">Fig. 15</a> on this page) explains itself. A chick was<span class="pagenum"><a id="Page_62"></a>[62]</span> -placed at A and left to find its way out. The walls were -made of books stuck up on end.</p> - -<p>Q was a similar pen arranged so that the real exit was -harder to find. (See <a href="#figure15-17">Fig. 16</a>.)</p> - -<p>R was still another pen similarly constructed, with four -possible avenues to be taken. (See <a href="#figure15-17">Fig. 17</a>.)</p> - -<p>S was a pen with walls 11 inches high. On the right side -an inclined plane of wire screening led from the floor of the -pen to the top of its front wall. Thence the chick could -jump down to where its fellows and the food and drink -were. S was 17 × 14 in size.</p> - -<p>T was a pen of the same size as S, with a block of wood 3 -inches by 3 and 2 inches high in the right back corner. -From this an inclined plane led to the top of the front wall -(on the right side of the box). But a partition was placed -along the left edge of this plane, so that a chick could reach -it only <i>via</i> the wooden block, not by a direct jump.</p> - -<p>U was a pen 16 × 14 × 10 inches. Along the back -toward the right corner were placed a series of steps 1½ -inches wide, the first 1, the second 2, and the third 3 inches -high. In the corner was a platform 4 × 4, and 4 high, from -which access to the top of the front wall of the pen could -be gained by scrambling up inside a stovepipe 11 inches -long, inclined upward at an angle of about 30°. From -the edge of the wall the chick could, of course, jump down to -food and society. The top of the pen was covered so that -the chick could not from the platform jump onto the edge -of the stovepipe or the top of the pen wall. The only -means of exit was to go up the steps to the platform, up -through the stovepipe to the front wall, and then jump -down.</p> - -<p>The time-curves for chicks 90, 91, 92, 93, 94 and 95, all -2-8 days old when experimented on, follow on <a href="#Page_65">page 65</a>.<span class="pagenum"><a id="Page_63"></a>[63]</span> -The scale is the same as that in the curves of the cats and -dogs. Besides these simple acts, which any average chick -will accidentally hit upon and associate, there are, in the -records of my preliminary study of animal intelligence, -a multitude of all sorts of associations which some chicks -have happened to form. Chicks have escaped from confinement -by stepping on a little platform in the back of the box, -by jumping up and pulling a string like that in D, by pecking -at a door, by climbing up a spiral staircase and out -through a hole in the wall, by doing this and then in addition -walking across a ladder for a foot to another wall -from which they jump down, etc. Not every chick will -happen upon the right way in these cases, but the chicks -who did happen upon it all formed the associations perfectly -after enough trials.</p> - -<p>The behavior of the chicks shows the same general character -as that of the cats, conditioned, of course, by the different -nature of the instinctive impulses. Take a chick put in T -(inclined plane) for an example. When taken from the food -and other chicks and dropped into the pen he shows evident -signs of discomfort; he runs back and forth, peeping loudly, -trying to squeeze through any openings there may be, -jumping up to get over the wall, and pecking at the bars -or screen, if such separate him from the other chicks. -Finally, in his general running around he goes up the inclined -plane a way. He may come down again, or he may go on -up far enough to see over the top of the wall. If he does, -he will probably go running up the rest of the way and jump -down. With further trials he gains more and more of an -impulse to walk up an inclined plane when he sees it, while -the vain running and pecking, etc., are stamped out by the -absence of any sequent pleasure. Finally, the chick goes -up the plane as soon as put in. In scientific terms this<span class="pagenum"><a id="Page_64"></a>[64]</span> -history means that the chick, when confronted by loneliness -and confining walls, responds by those acts which in similar -conditions in nature would be likely to free him. Some one -of these acts leads him to the successful act, and the resulting -pleasure stamps it in. Absence of pleasure stamps all -others out. The case is just the same as with dogs and cats. -The time-curves are shown in <a href="#figure18">Fig. 18</a>.</p> - -<p>Coming now to the question of differences in intelligence -between the different animals, it is clear that such differences -are hard to estimate accurately. The chicks are -surely very much slower in forming associations and less -able to tackle hard ones, but the biggest part of the difference -between what they do and what the dogs and cats do -is not referable so much to any difference in intelligence as to -a difference in their bodily organs and instinctive impulses. -As between dogs and cats, the influence of the difference -in quantity of activity, in the direction of the instinctive -impulses, in the versatility of the fore limb, is hard to -separate from the influence of intelligence proper. The -best practical tests to judge such differences in general -would be differences in memory, which are very easily got -at, differences in the delicacy and complexity attainable, -and, of course, differences in the slope of the curves for the -same association. If all these tests agreed, we should have -a right to rank one animal above the other in a scale of -intelligence. But this whole question of grading is, after -all, not so important for comparative psychology as its -popularity could lead one to think. Comparative psychology -wants first of all to trace human intellection back -through the phylum to its origin, and in this aim is helped -little by knowing that dogs are brighter than cats, or -whales than seals, or horses than cows. Further, the whole -question of ‘intelligence’ should be resolved into particular -inquiries into the development of attention, activity, -memory, etc.</p> - -<p><span class="pagenum"><a id="Page_65"></a>[65]</span></p> - -<div class="figcenter illowp48" id="figure18" style="max-width: 28.125em;"> - <img class="w100" src="images/figure18.jpg" alt=""> - <p class="caption"><span class="smcap">Fig. 18.</span></p> -</div> - -<p><span class="pagenum"><a id="Page_66"></a>[66]</span></p> - -<p>So far as concerns dogs and cats, I should decide that -the former were more generally intelligent. The main -reason, however, why dogs seem to us so intelligent is not -a good reason for the belief. It is because, more than any -other domestic animal, they direct their attention to <i>us</i>, to -what we do, and so form associations connected with acts -of ours.</p> - -<p>Having finished our attempt to give a true description of -the facts of association, so far as observed from the outside, -we may now progress to discuss its inner nature. A little -preface about certain verbal usages is necessary before doing -so. Throughout I shall use the word ‘animal’ or ‘animals,’ -and the reader might fancy that I took it for granted that -the associative processes were the same in all animals as -in these cats and dogs of mine. Really, I claim for my -animal psychology only that it is the psychology of just -these particular animals. What this warrants about animals -in general may be left largely to the discretion of -the reader. As I shall later say, it is probable that in regard -to imitation and the power of forming associations -from a lot of free ideas, the anthropoid primates are essentially -different from the cats and dogs.</p> - -<p>The reasons why I say ‘animals’ instead of ‘dogs and -cats of certain ages’ are two. I do think that the probability -that the other mammals, barring the primates, offer no -objections to the theories here advanced about dogs and -cats is a very strong probability, strong enough to force -the burden of proof upon any one who should, for instance, -say that horse-goat psychology was not like cat-dog psychology -in these general matters. I should claim that, -till the contrary was shown in any case, my statements<span class="pagenum"><a id="Page_67"></a>[67]</span> -should stand for the mammalian mind in general, barring the -primates. My second reason is that I hate to burden the -reader with the disgusting rhetoric which would result if -I had to insert particularizations and reservations at every -step. The word ‘animal’ is too useful, rhetorically, to be -sacrificed. Finally, inasmuch as most of my theorizing -will be in the line of denying certain relatively high functions -to animals, the evidence from cats and dogs is sufficient, -for they are from among the most intelligent animals, and -functions of the kind to be discussed, if absent in their -case, are probably absent from the others.</p> - -<h3><span class="smcap">Reasoning or Inference</span></h3> - -<p>The first great question is whether or not animals are ever -led to do any of their acts by reasoning. Do they ever conclude -from inference that a certain act will produce a certain -desired result, and so do it? The best opinion has been that -they do not. The best interpretation of even the most -extraordinary performances of animals has been that they -were the result of accident and association or imitation. -But it has after all been only opinion and interpretation, -and the opposite theory persistently reappears in the literature -of the subject. So, although it is in a way superfluous to -give the <i>coup de grâce</i> to the despised theory that animals -reason, I think it is worth while to settle this question once -for all.</p> - -<p>The great support of those who do claim for animals the -ability to infer has been their wonderful performances which -resemble our own. These could not, they claim, have happened -by accident. No animal could learn to open a latched -gate by accident. The whole substance of the argument -vanishes if, as a matter of fact, animals do learn those things<span class="pagenum"><a id="Page_68"></a>[68]</span> -by accident. <i>They certainly do.</i> In this investigation -choice was made of the intelligent performances described -by Romanes in the following passages. I shall quote at -some length because these passages give an admirable -illustration of an attitude of investigation which this research -will, I hope, render impossible for any scientist in -the future. Speaking of the general intelligence of cats, -Romanes says:</p> - -<div class="blockquote"> - -<p>“Thus, for instance, while I have only heard of one solitary -case ... of a dog which, without tuition, divined the use of a -thumb latch so as to open a closed door by jumping on the handle -and depressing the thumb-piece, I have received some half-dozen -instances of this display of intelligence on the part of -cats. These instances are all such precise repetitions of one -another that I conclude the fact to be one of tolerably ordinary -occurrence among cats, while it is certainly rare among dogs. -I may add that my own coachman once had a cat which, certainly -without tuition, learnt thus to open a door that led into -the stables from a yard into which looked some of the windows -of the house. Standing at these windows when the cat did not -see me, I have many times witnessed her <i>modus operandi</i>. -Walking up to the door with a most matter-of-course kind of air, -she used to spring at the half hoop handle just below the thumb -latch. Holding on to the bottom of this half-hoop with one -fore paw, she then raised the other to the thumb piece, and -while depressing the latter finally with her hind legs scratched -and pushed the door posts so as to open the door....</p> - -<p>“Of course in all such cases the cats must have previously -observed that the doors are opened by persons placing their -hands upon the handles and, having observed this, the animals -act by what may be strictly termed rational imitation. But -it should be observed that the process as a whole is something -more than imitative. For not only would observation alone be -scarcely enough (within any limits of thoughtful reflection that<span class="pagenum"><a id="Page_69"></a>[69]</span> -it would be reasonable to ascribe to an animal) to enable a cat -upon the ground to distinguish that the essential part of the -process consists not in grasping the handle, but in depressing -the latch; but the cat certainly never saw any one, after having -depressed the latch, pushing the door posts with his legs; and -that this pushing action is due to an originally deliberate intention -of opening the door, and not to having accidentally found -this action to assist the process, is shown by one of the cases -communicated to me; for in this case, my correspondent says, -‘the door was not a loose-fitting one, by any means, and I was -surprised that by the force of one hind leg she should have been -able to push it open after unlatching it.’ Hence we can only -conclude that the cats in such cases have a very definite idea as -to the mechanical properties of a door: they know that to make -it open, even when unlatched, it requires to be <i>pushed</i>—a very -different thing from trying to imitate any particular action which -they may see to be performed for the same purpose by man. -The whole psychological process, therefore, implied by the fact -of a cat opening a door in this way is really most complex. -First the animal must have observed that the door is opened by -the hand grasping the handle and moving the latch. Next she -must reason, by ‘the logic of feelings’—‘If a hand can do it, -why not a paw?’ Then strongly moved by this idea she makes -the first trial. The steps which follow have not been observed, -so we cannot certainly say whether she learns by a succession -of trials that depression of the thumb piece constitutes the -essential part of the process, or, perhaps more probably, that her -initial observations supplied her with the idea of clicking the -thumb piece. But, however this may be, it is certain that the -pushing with the hind feet after depressing the latch must -be due to adaptive reasoning unassisted by observation; and -only by the concerted action of all her limbs in the performance -of a highly complex and most unnatural movement is -her final purpose attained.” (Animal Intelligence, pp. 420-422.)</p> - -</div> - -<p><span class="pagenum"><a id="Page_70"></a>[70]</span></p> - -<p>A page or two later we find a less ponderous account of -a cat’s success in turning aside a button and so opening a -window:—</p> - -<div class="blockquote"> - -<p>“At Parara, the residence of Parker Bowman, Esq., a full-grown -cat was one day accidentally locked up in a room without -any other outlet than a small window, moving on hinges, and -kept shut by means of a swivel. Not long afterwards the window -was found open and the cat gone. This having happened -several times, it was at last found that the cat jumped upon the -window sill, placed her fore paws as high as she could reach -against the side, deliberately reached with one over to the -swivel, moved it from its horizontal to a vertical position, and -then, leaning with her whole weight against the window, swung -it open and escaped.” (Animal Intelligence, p. 425.)</p> - -</div> - -<p>A description has already been given on <a href="#Page_31">page 31</a> of the -small box (C), whose door fell open when the button was -turned, and also of a large box (CC) for the dogs, with a -similar door. The thumb-latch experiment was carried -on with the same box (G) for both cats and dogs, but the -door was arranged so that a greater force (1.3 kilograms) -was required in the case of the dogs. It will be remembered -that the latch was so fixed that if the thumb piece were -pressed down, without contemporaneous outward pressure -of the door, the latch bar would merely drop back into its -catch as soon as the paw was taken off the door. If, however, -the door were pushed outward, the latch bar, being -pressed closely against the outer edge of its catch, would, -if lifted, be likely to fall outside it and so permit the door -to open if then or later sufficient pressure were exerted. -Eight cats (Nos. 1, 2, 3, 4, 5, 6, 7 and 13) were, one at a time, -left in this thumb-latch box. All exhibited the customary -instinctive clawings and squeezings and bitings. Out of -the eight all succeeded in the course of their vigorous<span class="pagenum"><a id="Page_71"></a>[71]</span> -struggles in pressing down the thumb piece, so that if the -door had been free to swing open, they could have escaped. -Six succeeded in pushing both thumb-piece down and door -out, so that the bar did not fall back into its place. Of -these five succeeded in also later pushing the door open, -so that they escaped and got the fish -outside. Of these, three, after repeated -trials, associated the complicated -movements required with -the sight of the interior of the box so -firmly that they attacked the thumb -latch the moment they were put in. -The history of the formation of the -association in the case of 3 and of 4 is -shown in the curves in <a href="#figure06">Figs. 6 and 7</a>. -In the case of 13 the exact times were -not taken. The combination of accidents -required was enough to make -No. 1 and No. 6 take a long time -to get out. Consequently, weariness -and failure inhibited their impulses -to claw, climb, etc., more than the -rare pleasure from getting out -strengthened them, and they failed -to form the association. Like the -cats who utterly failed to get out, they finally ceased -to try when put in. The history of their efforts is as in -Table 3: the figures in the columns represent the time (in -minutes and seconds) the animal was in the box before -escaping or before being taken out if he failed to escape. -Cases of failure are designated by an F after the -figures. Double lines represent an interval of twenty-four -hours.</p> - -<h4><span class="smcap">Table 3</span></h4> - -<table> - <tr> - <th colspan="2" class="bl br bt">No. 1.</th> - <th colspan="2" class="br bt">No. 6.</th> - </tr> - <tr> - <td class="tdr bl bt2">13.00</td> - <td class="bt2 br">F</td> - <td class="tdr bt2">17.50</td> - <td class="bt2 br"></td> - </tr> - <tr> - <td class="tdr bl">9.30</td> - <td class="br"></td> - <td class="tdr">3.30</td> - <td class="br"></td> - </tr> - <tr> - <td class="tdr bl">1.40</td> - <td class="br"></td> - <td class="tdr">9.00</td> - <td class="br"></td> - </tr> - <tr> - <td class="tdr bl">.50</td> - <td class="br"></td> - <td class="tdr">2.10</td> - <td class="br"></td> - </tr> - <tr> - <td class="tdr bl">15.00</td> - <td class="br"></td> - <td class="tdr">1.45</td> - <td class="br"></td> - </tr> - <tr> - <td class="tdr bl">6.00</td> - <td class="br">F</td> - <td class="tdr">1.55</td> - <td class="br"></td> - </tr> - <tr> - <td class="tdr bl bt2">14.00</td> - <td class="bt2 br"></td> - <td class="tdr">13.00</td> - <td class="br"></td> - </tr> - <tr> - <td class="tdr bl">20.00</td> - <td class="br">F</td> - <td class="tdr bt2">5.00</td> - <td class="bt2 br"></td> - </tr> - <tr> - <td class="tdr bl">4.30</td> - <td class="br"></td> - <td class="tdr">2.30</td> - <td class="br"></td> - </tr> - <tr> - <td class="tdr bl">20.00</td> - <td class="br">F</td> - <td class="tdr">15.00</td> - <td class="br"></td> - </tr> - <tr> - <td class="tdr bl">20.00</td> - <td class="br">F</td> - <td class="tdr">10.00</td> - <td class="br">F</td> - </tr> - <tr> - <td class="tdr bl">15.00</td> - <td class="br">F</td> - <td class="tdr bt2">5.00</td> - <td class="bt2 br"></td> - </tr> - <tr> - <td class="tdr bl bt2">60.00</td> - <td class="bt2 br">F</td> - <td class="tdr">15.00</td> - <td class="br">F</td> - </tr> - <tr> - <td class="tdr bl"></td> - <td class="br"></td> - <td class="tdr bt2">10.00</td> - <td class="bt2 br">F</td> - </tr> - <tr> - <td class="tdr bl bb"></td> - <td class="bb br"></td> - <td class="tdr bt2 bb">10.00</td> - <td class="bt2 br bb">F</td> - </tr> -</table> - -<p><span class="pagenum"><a id="Page_72"></a>[72]</span></p> - -<p>It should be noted that, although cats 3 and 4 had had -some experience in getting out of boxes by clawing at loops -and turning buttons, they had never had anything at all -like a thumb latch to claw at, nor had they ever seen the -door opened by its use, nor did they even have any experience -of the fact that the part of the box where the thumb -piece was was the door. And we may insert here, what -will be stated more fully later, that there was displayed -no observation of the surroundings or deliberation upon -them. It was just a mad scramble to get out.</p> - -<p>Three dogs (1, 2 and 3) were given a chance to liberate -themselves from this same box. 2 and 3, who were rather -inactive, failed to even push the thumb piece down. No. 1, -who was very active, did push it down at the same time -that she happened to be pushing against the door. She -repeated this and formed the association as shown in the -curve on <a href="#Page_60">page 60</a>. She had had experience only of escaping -by pulling a loop of string.</p> - -<p>Out of 6 cats who were put in the box whose door opened -by a button, not one failed, in the course of its impulsive -activity, to push the button around. Sometimes it was -clawed to one side from below; sometimes vigorous pressure -on the top turned it around; sometimes it was pushed up -by the nose. No cat who was given repeated trials failed -to form a perfect association between the sight of the interior -of that box and the proper movements. Some of -these cats had been in other boxes where pulling a loop of -string liberated them, 3 and 4 had had considerable experience -with the boxes and probably had acquired a general -tendency to claw at loose objects. 10, 11 and 12 had never -been in <i>any box</i> before. The curves are on <a href="#Page_41">pages 41 and 43</a>.</p> - -<p>Of two dogs, one, when placed in a similar but larger -box, succeeded in hitting the button in such a way as to let<span class="pagenum"><a id="Page_73"></a>[73]</span> -the door open, and formed a permanent association, as -shown by the curves on <a href="#Page_41">page 41</a>. No one who had seen the -behavior of these animals when trying to escape could -doubt that their actions were directed by instinctive impulses, -not by rational observation. It is then absolutely -sure that a dog or cat <i>can</i> open a door closed by a thumb -latch or button, merely by the accidental success of its -natural impulses. If <i>all</i> cats, when hungry and in a <i>small</i> -box, will accidentally push the button that holds the door, -an <i>occasional</i> cat in a <i>large</i> room may very well do the same. -If three cats out of eight will accidentally press down a -thumb piece and push open a small door, three cats out of -a thousand may very well open doors or gates in the same -way.</p> - -<p>But besides thus depriving of their value the facts which -these theorizers offer as evidence, we may, by a careful -examination of the method of formation of these associations -as it is shown in the time-curves, gain positive evidence that -no power of inference was present in the subjects of the experiments. -Surely if 1 and 6 had possessed any power of -inference, they would not have failed to get out after having -done so several times. Yet they did. (See <a href="#Page_71">p. 71</a>.) If they -had once even, much less if they had six or eight times, -inferred what was to be done, they should have made the -inference the seventh or ninth time. And if there were in -these animals any power of inference, however rudimentary, -however sporadic, however dim, there should have appeared -among the multitude some cases where an animal, seeing -through the situation, knows the proper act, does it, and -from then on does it immediately upon being confronted -with the situation. There ought, that is, to be a sudden -vertical descent in the time-curve. Of course, where the -act resulting from the impulse is very simple, very obvious,<span class="pagenum"><a id="Page_74"></a>[74]</span> -and very clearly defined, a single experience may make the -association perfect, and we may have an abrupt descent -in the time-curve without needing to suppose inference. -But if in a complex act, a series of acts or an ill-defined act, -one found such a sudden consummation in the associative -process, one might very well claim that reason was at work. -Now, the scores of cases recorded show no such phenomena. -The cat does not look over the situation, much less <i>think</i> it -over, and then decide what to do. It bursts out at once -into the activities which instinct and experience have -settled on as suitable reactions to the situation ‘<i>confinement -when hungry with food outside</i>.’ It does not ever in the -course of its successes realize that such an act brings food -and therefore decide to do it and thenceforth do it immediately -from <i>decision</i> instead of from impulse. The one -impulse, out of many accidental ones, which leads to pleasure, -becomes strengthened and stamped in thereby, and -more and more firmly associated with the sense-impression -of that box’s interior. Accordingly it is sooner and sooner -fulfilled. Futile impulses are gradually stamped out. -The gradual slope of the time-curve, then, shows the absence -of reasoning. They represent the wearing smooth of -a path in the brain, not the decisions of a rational consciousness.</p> - -<p>In a later discussion of imitation further evidence that -animals do not reason will appear. For the present, suffice -it to say, that a dog, or cat, or chick, who does not in his -own impulsive activity learn to escape from a box by pulling -the proper loop, or stepping on a platform, or pecking at a -door, will not learn it from seeing his fellows do so. They -are incapable of even the inference (if the process may be -dignified by that name) that what gives another food will -give it to them also. So, also, it will be later seen that an<span class="pagenum"><a id="Page_75"></a>[75]</span> -animal cannot learn an act by being put through it. For -instance, a cat who fails to push down a thumb piece and -push out the door cannot be taught by having one take -its paw and press the thumb piece down with it. This -<i>could</i> be learned by a certain type of associative process -without inference. <i>Were there inference, it surely would be -learned.</i></p> - -<p>Finally, attention may be called to the curves which -show the way that the animal mind deals with a series -of acts (<i>e.g.</i> curves for G, J, K, L and O, found on <a href="#Page_45">pages 45 -to 55</a> and <a href="#Page_60">60</a>). Were there any reasoning the animals ought -early to master the method of escape in these cases (see -descriptions on <a href="#Page_31">pages 31 to 34</a>) so as to do the several -acts in order, and not to repeat one after doing it once, or -else ought utterly to fail to master the thing. But, in all -these experiments, where there was every motive for the -use of any reasoning faculty, if such existed, where the animals -literally lived by their intellectual powers, one finds -no sign of abstraction, or inference, or judgment.</p> - -<p>So far I have only given facts which are quite uninfluenced -by any possible incompetence or prejudice of the observer. -These alone seem to disprove the existence of any rational -faculty in the subjects experimented on. I may add that -my observations of all the conduct of all these animals -during the months spent with them, failed to find any act -that even <i>seemed</i> due to reasoning. I should claim that this -quarrel ought now to be dropped for good and all,—that -investigation ought to be directed along more sensible and -profitable lines. I should claim that the psychologist who -studies dogs and cats in order to defend this ‘reason’ theory -is on a level with a zoölogist who should study fishes with -a view to supporting the thesis that they possessed clawed -digits. The rest of this account will deal with more promising<span class="pagenum"><a id="Page_76"></a>[76]</span> -problems, of which the first, and not the least important, -concerns the facts and theories of <i>imitation</i>.</p> - -<h3><span class="smcap">Imitation</span></h3> - -<p>To the question, ‘Do animals imitate?’ science has -uniformly answered, ‘Yes.’ But so long as the question -is left in this general form, no correct answer to it is possible. -It will be seen, from the results of numerous experiments -soon to be described, that imitation of a certain sort is -not possible for animals, and before entering upon that -description it will be helpful to differentiate this matter of -imitation into several varieties or aspects. The presence -of some sorts of imitation does not imply that of other -sorts.</p> - -<p>There are, to begin with, the well-known phenomena -presented by the imitative birds. The power is extended -widely, ranging from the parrot who knows a hundred or -more articulate sounds to the sparrow whom a patient -shoemaker taught to get through a tune. Now, if a bird -really gets a sound in his mind from hearing it and sets out -forthwith to imitate it, as mocking birds are said at times to -do, it is a mystery and deserves closest study. If a bird, -out of a lot of random noises that it makes, chooses those -for repetition which are like sounds that he has heard, it -is again a mystery <i>why</i>, though not as in the previous case -a mystery <i>how</i>, he does it. The important fact for our purpose -is that, though the imitation of sounds is so habitual, -there does not appear to be any marked general imitative -tendency in these birds. There is no proof that parrots do -muscular acts from having seen other parrots do them. -But this should be studied. At any rate, until we know -what sort of sounds birds imitate, what circumstances<span class="pagenum"><a id="Page_77"></a>[77]</span> -or emotional attitudes these are connected with, how they -learn them and, above all, whether there is in birds which -repeat sounds any tendency to imitate in other lines, we -cannot, it seems to me, connect these phenomena with -anything found in the mammals or use them to advantage -in a discussion of animal imitation as the forerunner of -human. In what follows they will be left out of account, -will be regarded as a specialization removed from the general -course of mental development, just as the feathers or right -aortic arch of birds are particular specializations of no consequence -for the physical development of mammals. For -us, henceforth, imitation will mean imitation minus the -phenomena of imitative birds.</p> - -<p>There are also certain pseudo-imitative or semi-imitative -phenomena which ought to be considered by themselves. -For example, the rapid loss of the fear of railroad trains or -telegraph wires among birds, the rapid acquisition of arboreal -habits among Australian rodents, the use of proper -feeding grounds, etc., may be held to be due to imitation. -The young animal stays with or follows its mother from a -specific instinct to keep near that particular object, to wit, -its mother. It may thus learn to stay near trains, or -scramble up trees, or feed at certain places and on certain -plants. Actions due to following pure and simple may thus -simulate imitation. Other groups of acts which now seem -truly imitative may be indirect fruits of some one instinct. -This must be kept in mind when one estimates the supposed -imitation of parents by young. Further, it is certain that -in the case of the chick, where early animal life has been -carefully observed, instinct and individual experience between -them rob imitation of practically all its supposed influence. -Chicks get along without a mother very well. -Yet no mother takes more care of her children than the<span class="pagenum"><a id="Page_78"></a>[78]</span> -hen. Care in other cases, then, need not mean instruction -through imitation.</p> - -<p>These considerations may prevent an unreserved acceptance -of the common view that young animals get a great -number of their useful habits from imitation, but I do not -expect or desire them to lead to its summary rejection. -I should not now myself reject it, though I think it quite -possible that more investigation and experiment may -finally reduce all the phenomena of so-called imitation of -parents by young to the level of indirect results of instinctive -acts.</p> - -<p>Another special department of imitation may be at least -vaguely marked off: namely, apparent imitation of certain -limited sorts of acts which are somewhat frequent in the -animal’s life. An example will do better than further -definition.</p> - -<p>Some sheep were being driven on board ship one at a time. -In the course of their progress they had to jump over a -hurdle. On this being removed before all had passed it, -the next sheep was seen to jump as if to get over a hurdle, -and so on for five or six, apparently sure evidence that they -imitated the action, each of the one in front. Now, it is -again possible that among gregarious animals there may be -elaborate connections in the nervous system which allow -the sight of certain particular acts in another animal to -arouse the innervation leading to those acts, but that these -connections are <i>limited</i>. The reactions on this view are -specific responses to definite signals, comparable to any -other instinctive or associational reaction. The sheep -jumps when he sees the other sheep jump, not because of -a general ability to do what he sees done, but because he is -furnished with the instinct to jump at such a sight, or -because his experience of following the flock over boulders<span class="pagenum"><a id="Page_79"></a>[79]</span> -and brooks and walls has got him into the habit of jumping -at the spot where he sees one ahead of him jump; and so -he jumps even though no obstacle be in his way. If due -to instinct, the only peculiarity of such a reaction would be -that the sense-impression calling forth the act would be the -same act as done by another. If due to experience, there -would be an exact correspondence to the frequent acts -called forth <i>originally</i> by several elements in a sense-impression, -one of which is essential, and done <i>afterwards</i> -when only the <i>non-essentials</i> are present. These two -possibilities have not been sufficiently realized, yet they -may contain the truth. On the other hand, these limited -acts may be the primitive, sporadic beginnings of the -general imitative faculty which we find in man. To this -general faculty we may now turn, having cleared away -some of the more doubtful phenomena which have shared -its name.</p> - -<p>It should be kept in mind that an imitative act may be -performed quite unthinkingly, as when a man in the mob -shouts what the others shout or claps when the others clap; -may be done from an inference that since A by doing X makes -pleasure for himself, I by doing X may get pleasure for myself; -may, lastly, be done from what may be called a transferred -association. This process is the one of interest in -connection with our general topic, and most of my experiments -on imitation were directed to the investigation -of it. Its nature is simple. One sees the following sequence: -‘A turning a faucet, A getting a drink.’ If one -can free this association from its narrow confinement to A, -so as to get from it the association, ‘impulse to turn faucet, -<i>me</i> getting a drink,’ one will surely, if thirsty, turn the -faucet, though he had never done so before. If one can -from an act witnessed learn to do the act, he in some way<span class="pagenum"><a id="Page_80"></a>[80]</span> -makes use of the sequence seen, transfers the process to -himself; in the common human sense of the word, he -<i>imitates</i>. This kind of imitation is surely common in -human life. It may be apparent in ontogeny before any -power of inference is shown. After that power does appear, -it still retains a wide scope, and teaches us a majority, perhaps, -of the ordinary accomplishments of our practical life.</p> - -<p>Now, as the writers of books about animal intelligence -have not differentiated this meaning from the other possible -ones, it is impossible to say surely that they have uniformly -credited it to animals, and it is profitless to catalogue here -their vague statements. Many opposers of the ‘reason’ -theory have presupposed such a process and used it to replace -reason as the cause of some intelligent performances. The -upholders of the reason theory have customarily recognized -such a process and claimed to have discounted it in their -explanations of the various anecdotes. So we found -Mr. Romanes, in the passage quoted, discussing the possibility -that such an imitative process, without reason, could -account for the facts. In his chapter on Imitation in -‘Habit and Instinct,’ Principal C. Lloyd Morgan, the sanest -writer on comparative psychology, seems to accept imitation -of this sort as a fact, though he could, if attacked, -explain most of his illustrations by the simple forms. The -fact is, as was said before, that no one has analyzed or -systematized the phenomena, and so one cannot find clear, -decisive statements to quote.</p> - -<p>At any rate, whether previous authorities have agreed -that such a process is present or not, it is worth while to -tackle the question; and the formation of associations by -imitation, if it occurs, is an important division of the formation -of associations in general. The experiments and their -results may now be described.</p> - -<p><span class="pagenum"><a id="Page_81"></a>[81]</span></p> - -<h4><span class="smcap">Imitation in Chicks</span></h4> - -<p>No. 64 learned to get out of a certain pen (16 × 10 inches) -by crawling under the wire screening at a certain spot. -There was also a chance to get out by walking up an inclined -plane and then jumping down. No. 66 was put in with 64. -After 9 minutes 20 seconds, 66 went out by the inclined -plane, although 64 had in the meantime crawled out under -the screen 9 times. (As soon as he got out and ate a little -he was put back.) It was impossible to judge how many -of these times 66 really saw 64 do this. He was looking in -that direction 5 of the times. So also, in three more trials, -66 used the inclined plane, though 64 crawled under each -time. 67 was then tried. In 4 minutes 10 seconds, he -crawled under, 64 having done so twice. Being then put -in <i>alone</i>, he, without the chance to imitate, still crawled -under. So probably he went under <i>when with 64</i> not by -imitation but by accident, just as 64 had learned the thing -himself.</p> - -<div class="figcenter illowp100" id="figure19-20" style="max-width: 25em;"> - <img class="w100" src="images/figure19-20.jpg" alt=""> - <p class="caption">Fig. 19. Fig. 20.</p> -</div> - -<p>The accompanying figure (<a href="#figure19-20">19</a>) shows the apparatus used -in the next experiment. A represents the top of a box -(5 × 4 inches), 13 inches above the level of the floor C. -On the floor C were the chicks and food. B is the top of -a box 10 inches high. Around the edges of A except the -one next B a wire screen was placed, and 65 was repeatedly<span class="pagenum"><a id="Page_82"></a>[82]</span> -put upon A until he learned to go quickly back to C <i>via</i> B. -Then the screen was bent outward at X so that a chick -could barely squeeze through and down (A to C). Eleven -chicks were then one at a time placed on A with 65. In -every case but one they went A-C. In the case of the chick -(75) who went A-B-C, there could have been no imitation, -for he went down <i>before</i> 65 did. One other went through -the hole before 65 went to B. The remaining nine all had -a chance to imitate 65 and to save the uncomfortable -struggle to get through the hole, 65 going A-B-C 8 times -before 68 went A-C, 2 times when with 66 and 76, once in -the case of each of the others.</p> - -<p>In still another experiment the apparatus was (as shown in -<a href="#figure19-20">Fig. 20</a>) a pen 14 inches square, 10 inches high, with a wire -screen in front and a hole 3½ inches square in the back. -This hole opened into a passageway (B) leading around to C, -where were the other chicks and food. Chicks who had -failed, when put in alone, to find the way out, were put in -with other chicks who had learned the way, to see if by -seeing them go out they would learn the way. Chick 70 -was given 4 trials alone, being left in the box 76 minutes all -told. He was then given 9 trials (165 minutes) with another -chick who went out <i>via</i> B 36 times. 70 failed to follow him -on any occasion. The trials were all given in the course -of two days. Chick 73 failed in 1 trial (12 minutes) to get -out of himself, and was then given 4 trials (94 minutes) -with another chick who went out <i>via</i> B 33 times. In this -experiment, as in all others reported, sure evidence that the -animals wanted to get out, was afforded by their persistent -peckings and jumpings at the screen or bars that stood -between them and C. Chick 72, after 8 unsuccessful trials -alone (41 minutes), was given 8 trials with a chance to -imitate. After the other chick had gone out 44 times, 72<span class="pagenum"><a id="Page_83"></a>[83]</span> -<i>did go out</i>. He did not follow the other but went 20 seconds -later. It depends upon one’s general opinion whether one -shall attribute this one case out of three to accident or -imitation.</p> - -<p>I also took two chicks, one of whom learned to escape -from A (in <a href="#figure19-20">Fig. 19</a>) by going to B and jumping down the -side to the <i>right</i> of A, the other of whom learned to jump -down the side to the <i>left</i>, and placed them together upon A. -Each took his own course uninfluenced by the other in 10 trials.</p> - -<p>Chicks were also tried in several pens where there was only -one possible way of escape to see if they would learn it <i>more -quickly</i> when another chick did the thing several times before -their eyes. The method was to give some chicks their first -trial with an imitation possibility and their second without, -while others were given their first trial without and their -second with. If the ratio of the average time of the first -trial to the average time of the second is smaller in the first -class than it is in the second class, we may find evidence of -this sort of influence by imitation. Though imitation may -not be able to make an animal <i>do</i> what he would otherwise -<i>not do</i>, it may make him do <i>quicker</i> a thing he would have -done sooner or later any way. As a fact the ratio is <i>much -larger</i>. This is due to the fact that a chick, when in a pen -with another chick, is not afflicted by the discomfort of loneliness, -and so does not try so hard to get out. So the other -chick, who is continually being put in with him to teach -him the way out, really prolongs his stay in. This factor -destroys the value of these quantitative experiments, and -I do not insist upon them as evidence against imitation, -though they certainly offer none for it. I do not give -descriptions of the apparatus used in these experiments or a -detailed enumeration of the results, because in this discussion -we are not dealing primarily with imitation as a<span class="pagenum"><a id="Page_84"></a>[84]</span> -slight general factor in forming experience, but as a definite -associational process in the mind. The utter absence of -imitation in this limited sense is apparently demonstrated -by the results of the following experiments.</p> - -<p>V was a box 16 × 12 × 8½, with the front made of wire -screening and at the left end a little door held by a bolt but -in such a way that a sharp peck at the top of the door would -force it open.</p> - -<p>W was a box of similar size, with a door in the same place -fixed so that it was opened by raising a bolt. To this bolt -was tied a string which went up over the top of the edge of -the box and back across the box, as in D. By jumping up -and coming down with the head over this thread, the bolt -would be pulled up. The thread was 8½ inches above the floor.</p> - -<p>X was a box of similar size, with door, bolt and string -likewise. But here the string continued round a pulley at -the back down to a platform in the corner of the box. By -stepping on the platform the door was opened.</p> - -<p>Y was a box 12 × 8 × 8½, with a door in the middle of the -front, which I myself opened when a chick pecked at a tack -which hung against the front of the box 1½ inches above the -top of the door.</p> - -<p>These different acts, pecking at a door, jumping up and -with the neck pulling down a string, stepping on a platform, -and pecking at a tack, were the ones which various chicks -were given a chance to imitate. The chicks used were from -16 to 30 days old. The method of experiment was to put -a chick in, leave him 60 to 80 seconds, then put in another -who knew the act, and on his performing it, to let both -escape. No cases were counted unless the imitator apparently -saw the other do the thing. After about ten such -chances to learn the act, the imitator was left in alone for -ten minutes. The following table gives the results. The<span class="pagenum"><a id="Page_85"></a>[85]</span> -imitators, of course, had previously failed to form the association -of themselves. F denotes failure to perform the act:</p> - -<h5><span class="smcap">Table 4</span></h5> - -<table class="borders"> - <tr> - <th><span class="smcap">Chick</span></th> - <th><span class="smcap">Act</span></th> - <th><span class="smcap">No. Times<br>Saw</span></th> - <th colspan="2"><span class="smcap">Time in<br>Which Failed</span></th> - <th colspan="2"><span class="smcap">Final Time</span></th> - </tr> - <tr> - <td class="tdc">84</td> - <td class="tdc">V</td> - <td class="tdr">38</td> - <td class="tdr">45.00</td> - <td class="nobl">F</td> - <td class="tdr">15.00</td> - <td class="nobl">F</td> - </tr> - <tr> - <td class="tdc">85</td> - <td class="tdc">V</td> - <td class="tdr">30</td> - <td class="tdr">30.00</td> - <td class="nobl">F</td> - <td class="tdr">10.00</td> - <td class="nobl">F</td> - </tr> - <tr> - <td class="tdc">86</td> - <td class="tdc">V</td> - <td class="tdr">44</td> - <td class="tdr">55.00</td> - <td class="nobl">F</td> - <td class="tdr">15.00</td> - <td class="nobl">F</td> - </tr> - <tr> - <td class="tdc">87</td> - <td class="tdc">V</td> - <td class="tdr">26</td> - <td class="tdr">35.00</td> - <td class="nobl">F</td> - <td class="tdr">15.00</td> - <td class="nobl">F</td> - </tr> - <tr> - <td class="tdc">80</td> - <td class="tdc">W</td> - <td class="tdr">54</td> - <td class="tdr">60.00</td> - <td class="nobl">F</td> - <td class="tdr">15.00</td> - <td class="nobl">F</td> - </tr> - <tr> - <td class="tdc">81</td> - <td class="tdc">W</td> - <td class="tdr">40</td> - <td class="tdr">45.00</td> - <td class="nobl">F</td> - <td class="tdr">15.00</td> - <td class="nobl">F</td> - </tr> - <tr> - <td class="tdc">87</td> - <td class="tdc">W</td> - <td class="tdr">27</td> - <td class="tdr">30.00</td> - <td class="nobl">F</td> - <td class="tdr">10.00</td> - <td class="nobl">F</td> - </tr> - <tr> - <td class="tdc">81</td> - <td class="tdc">X</td> - <td class="tdr">18</td> - <td class="tdr">20.00</td> - <td class="nobl">F</td> - <td class="tdr">10.00</td> - <td class="nobl">F</td> - </tr> - <tr> - <td class="tdc">82</td> - <td class="tdc">X</td> - <td class="tdr">21</td> - <td class="tdr">20.00</td> - <td class="nobl">F</td> - <td class="tdr">8.40</td> - <td class="nobl"><i>Did</i></td> - </tr> - <tr> - <td class="tdc">83</td> - <td class="tdc">X</td> - <td class="tdr">33</td> - <td class="tdr">35.00</td> - <td class="nobl">F</td> - <td class="tdr">15.00</td> - <td class="nobl">F</td> - </tr> - <tr> - <td class="tdc">84</td> - <td class="tdc">X</td> - <td class="tdr">46</td> - <td class="tdr">55.00</td> - <td class="nobl">F</td> - <td class="tdr">15.00</td> - <td class="nobl">F</td> - </tr> - <tr> - <td class="tdc">84</td> - <td class="tdc">Y</td> - <td class="tdr">45</td> - <td class="tdr">55.00</td> - <td class="nobl">F</td> - <td class="tdr">15.00</td> - <td class="nobl">F</td> - </tr> - <tr> - <td class="tdc">83</td> - <td class="tdc">Y</td> - <td class="tdr">29</td> - <td class="tdr">35.00</td> - <td class="nobl">F</td> - <td class="tdr">15.00</td> - <td class="nobl">F</td> - </tr> -</table> - -<p>Thus out of all these cases only one did the act in spite of -the ample chance for imitation. I have no hesitation in -declaring 82’s act in stepping on the platform the result -of mere accident, and am sure that any one who had watched -the experiments would agree.</p> - -<h4><span class="smcap">Imitation in Cats</span></h4> - -<p>By reference to the previous descriptions of apparatus, it -will be seen that box D was arranged with two compartments, -separated by a wire screen. The larger of these had -a front of wooden bars with a door which fell open when a -string stretched across the top was bitten or clawed down. -The smaller was closed by boards on three sides and by the -wire screen on the fourth. Through the screen a cat within -could see the one to be imitated pull the string, go out<span class="pagenum"><a id="Page_86"></a>[86]</span> -through the door thus opened and eat the fish outside. -When put in this compartment, the top being covered by -a large box, a cat soon gave up efforts to claw through the -screen, quieted down and watched more or less the proceedings -going on in the other compartment. Thus this apparatus -could be used to test the power of imitation. A cat who -had no experience with the means of escape from the large -compartment was put in the closed one; another cat, who -would do it readily, was allowed to go through the performance -of pulling the string, going out, and eating the -fish. Record was made of the number of times he did so -and of the number of times the imitator had his eyes clearly -fixed on him. These were called ‘times seen.’ Cases -where the imitator was looking in the general direction -of the ‘imitatee’ and might very well have seen him and -probably did, were marked ‘doubtful.’ In the remaining -cases the cat did not see what was done by his instructor. -After the imitatee had done the thing a number of times, -the other was put in the big compartment alone, and the -time it took him before pulling the string was noted and -his general behavior closely observed. If he failed in 5 or 10 -or 15 minutes to do so, he was released and not fed. This -entire experiment was repeated a number of times. From -the times taken by the imitator to escape and from observation -of the way that he did it, we can decide whether imitation -played any part. The history of several cases are -given in the following tables. In the first column are given -the lengths of time that the imitator was shut up in the box -watching the imitatee. In the second column is the number -of times that the latter did the trick. In the third and -fourth are the times that the imitator surely and possibly -saw it done, while in the last is given the time that, when -tried alone, the imitator took to pull the string, or if<span class="pagenum"><a id="Page_87"></a>[87]</span> -he failed, the time he was in the box trying to get out. -Times are in minutes and seconds, failures denoted by F:</p> - -<h5><span class="smcap">Table 5</span> (a)</h5> - -<table class="borders"> - <tr> - <th colspan="2"></th> - <th colspan="3"><span class="smcap">No. 7 Imitating No. 2</span></th> - <th colspan="2"></th> - </tr> - <tr> - <th></th> - <th>Time<br>Watching</th> - <th>No. of times<br>2 did</th> - <th>No. of times<br>7 saw</th> - <th>No. of times<br>Doubtful</th> - <th colspan="2">Time of 7<br>when alone</th> - </tr> - <tr> - <td></td> - <td class="tdr">10.00</td> - <td class="tdr">11</td> - <td class="tdr">3</td> - <td class="tdr">5</td> - <td class="tdr"></td> - <td class="nobl"></td> - </tr> - <tr> - <td>After 48 Hours</td> - <td class="tdr">11.00</td> - <td class="tdr">10</td> - <td class="tdr">4</td> - <td class="tdr">2</td> - <td class="tdr"></td> - <td class="nobl"></td> - </tr> - <tr> - <td></td> - <td class="tdr">12.00</td> - <td class="tdr">20</td> - <td class="tdr">4</td> - <td class="tdr">13</td> - <td class="tdr">10.00</td> - <td class="nobl">F</td> - </tr> - <tr> - <td></td> - <td class="tdr"></td> - <td class="tdr"></td> - <td class="tdr"></td> - <td class="tdr"></td> - <td class="tdr">1.00</td> - <td class="nobl"><a id="FNanchor_8" href="#Footnote_8" class="fnanchor">[8]</a></td> - </tr> - <tr> - <td>After 24 Hours</td> - <td class="tdr">8.00</td> - <td class="tdr">20</td> - <td class="tdr">6</td> - <td class="tdr">11</td> - <td class="tdr">3.30</td> - <td class="nobl"></td> - </tr> - <tr> - <td></td> - <td class="tdr"></td> - <td class="tdr"></td> - <td class="tdr"></td> - <td class="tdr"></td> - <td class="tdr">10.00</td> - <td class="nobl">F</td> - </tr> - <tr> - <td></td> - <td class="tdr">13.00</td> - <td class="tdr">25</td> - <td class="tdr">8</td> - <td class="tdr">12</td> - <td class="tdr">20.00</td> - <td class="nobl">F</td> - </tr> - <tr> - <td>After 24 Hours</td> - <td class="tdr">9.00</td> - <td class="tdr">20</td> - <td class="tdr">4</td> - <td class="tdr">11</td> - <td class="tdr">10.00</td> - <td class="nobl">F</td> - </tr> - <tr> - <td>After 24 Hours</td> - <td class="tdr">12.00</td> - <td class="tdr">35</td> - <td class="tdr">5</td> - <td class="tdr">21</td> - <td class="tdr">30.00</td> - <td class="nobl">F</td> - </tr> - <tr> - <td>After 2 Hours</td> - <td class="tdr">10.00</td> - <td class="tdr">25</td> - <td class="tdr">3</td> - <td class="tdr">8</td> - <td class="tdr">25.00</td> - <td class="nobl">F</td> - </tr> - <tr> - <td>After 24 Hours</td> - <td class="tdr">15.00</td> - <td class="tdr">35</td> - <td class="tdr">6</td> - <td class="tdr">21</td> - <td class="tdr">20.00</td> - <td class="nobl">F</td> - </tr> - <tr> - <td>After 24 Hours</td> - <td class="tdr">6.00</td> - <td class="tdr">20</td> - <td class="tdr">0</td> - <td class="tdr">7</td> - <td class="tdr">10.00</td> - <td class="nobl">F</td> - </tr> - <tr> - <td colspan="3" class="nw">Total times surely and possibly seen,—</td> - <td class="tdr nobl">43</td> - <td class="tdr nobl">111</td> - <td class="tdr"></td> - <td class="nobl"></td> - </tr> -</table> - -<h5><span class="smcap">Table 5</span> (b)</h5> - -<table class="borders"> - <tr> - <th colspan="2"></th> - <th colspan="3"><span class="smcap">No. 5 Imitating No. 2</span></th> - <th colspan="2"></th> - </tr> - <tr> - <th></th> - <th>Time<br>Watching</th> - <th>No. of times<br>2 did</th> - <th>No. of times<br>5 saw</th> - <th>No. of times<br>Doubtful</th> - <th colspan="2">Time of 5<br>when alone</th> - </tr> - <tr> - <td></td> - <td class="tdr">12.00</td> - <td class="tdr">15</td> - <td class="tdr">3</td> - <td class="tdr">8</td> - <td class="tdr">5.00</td> - <td class="nobl">F</td> - </tr> - <tr> - <td>After 2 Hours</td> - <td class="tdr">10.00</td> - <td class="tdr">8</td> - <td class="tdr">4</td> - <td class="tdr">4</td> - <td class="tdr"></td> - <td class="nobl"></td> - </tr> - <tr> - <td>After 24 Hours</td> - <td class="tdr">5.00</td> - <td class="tdr">5</td> - <td class="tdr">0</td> - <td class="tdr">3</td> - <td class="tdr"></td> - <td class="nobl"></td> - </tr> - <tr> - <td>After 1 Hour</td> - <td class="tdr">14.00</td> - <td class="tdr">10</td> - <td class="tdr">5</td> - <td class="tdr">3</td> - <td class="tdr">10.00</td> - <td class="nobl">F</td> - </tr> - <tr> - <td>After 1 Hour</td> - <td class="tdr">13.00</td> - <td class="tdr">22</td> - <td class="tdr">7</td> - <td class="tdr">11</td> - <td class="tdr">10.00</td> - <td class="nobl">F</td> - </tr> - <tr> - <td>After 24 Hours</td> - <td class="tdr">7.00</td> - <td class="tdr">15</td> - <td class="tdr">3</td> - <td class="tdr">8</td> - <td class="tdr">5.00</td> - <td class="nobl">F</td> - </tr> - <tr> - <td>After 48 Hours</td> - <td class="tdr">18.00</td> - <td class="tdr">20</td> - <td class="tdr">2</td> - <td class="tdr">9</td> - <td class="tdr">20.00</td> - <td class="nobl">F</td> - </tr> - <tr> - <td>After 24 Hours</td> - <td class="tdr">14.00</td> - <td class="tdr">20</td> - <td class="tdr">2</td> - <td class="tdr">10</td> - <td class="tdr">30.00</td> - <td class="nobl">F</td> - </tr> - <tr> - <td>After 24 Hours</td> - <td class="tdr">10.00</td> - <td class="tdr">20</td> - <td class="tdr">7</td> - <td class="tdr">12</td> - <td class="tdr">20.00</td> - <td class="nobl">F</td> - </tr> - <tr> - <td colspan="3" class="nw">Total times surely and possibly seen,—</td> - <td class="tdr nobl">33</td> - <td class="tdr nobl">68</td> - <td class="tdr"></td> - <td class="nobl"></td> - </tr> -</table> - -<p><span class="pagenum"><a id="Page_88"></a>[88]</span></p> - -<h5><span class="smcap">Table 5</span> (c)</h5> - -<table class="borders"> - <tr> - <th colspan="2"></th> - <th colspan="3"><span class="smcap">No. 6 Imitating No. 2</span></th> - <th colspan="2"></th> - </tr> - <tr> - <th></th> - <th>Time<br>Watching</th> - <th>No. of times<br>2 did</th> - <th>No. of times<br>6 saw</th> - <th>No. of times<br>Doubtful</th> - <th colspan="2">Time of 6<br>when alone</th> - </tr> - <tr> - <td></td> - <td class="tdr">12.00</td> - <td class="tdr">30</td> - <td class="tdr">0</td> - <td class="tdr">19</td> - <td class="tdr">1.10</td> - <td class="nobl"><a id="FNanchor_9" href="#Footnote_9" class="fnanchor">[9]</a></td> - </tr> - <tr> - <td>After 48 Hours</td> - <td class="tdr">11.00</td> - <td class="tdr">30</td> - <td class="tdr">0</td> - <td class="tdr">11</td> - <td class="tdr">9.30</td> - <td class="nobl"></td> - </tr> - <tr> - <td>After 72 Hours</td> - <td class="tdr">10.00</td> - <td class="tdr">30</td> - <td class="tdr">0</td> - <td class="tdr">15</td> - <td class="tdr">3.00</td> - <td class="nobl"></td> - </tr> - <tr> - <td>After 72 Hours</td> - <td class="tdr">6.00</td> - <td class="tdr">20</td> - <td class="tdr">3</td> - <td class="tdr">7</td> - <td class="tdr">1.50</td> - <td class="nobl"></td> - </tr> - <tr> - <td>After 24 Hours</td> - <td class="tdr">9.00</td> - <td class="tdr">30</td> - <td class="tdr">1</td> - <td class="tdr">13</td> - <td class="tdr">10.00</td> - <td class="nobl">F</td> - </tr> - <tr> - <td>After 24 Hours</td> - <td class="tdr">10.00</td> - <td class="tdr">30</td> - <td class="tdr">6</td> - <td class="tdr">9</td> - <td class="tdr">10.00</td> - <td class="nobl">F</td> - </tr> - <tr> - <td>After 24 Hours</td> - <td class="tdr">10.00</td> - <td class="tdr">30</td> - <td class="tdr">1</td> - <td class="tdr">8</td> - <td class="tdr">9.40</td> - <td class="nobl"></td> - </tr> - <tr> - <td colspan="3" class="nw">Total times surely and possibly seen,—</td> - <td class="tdr nobl">11</td> - <td class="tdr nobl">82</td> - <td class="tdr"></td> - <td class="nobl"></td> - </tr> -</table> - -<h5><span class="smcap">Table 5</span> (d)</h5> - -<table class="borders"> - <tr> - <th colspan="2"></th> - <th colspan="3"><span class="smcap">No. 3 Imitating No. 2</span></th> - <th colspan="2"></th> - </tr> - <tr> - <td></td> - <td class="tdr">8.00</td> - <td class="tdr">30</td> - <td class="tdr">2</td> - <td class="tdr">19</td> - <td class="tdr">3.30</td> - <td class="nobl"><a id="FNanchor_10" href="#Footnote_10" class="fnanchor">[10]</a></td> - </tr> - <tr> - <td></td> - <td class="tdr"></td> - <td class="tdr"></td> - <td class="tdr"></td> - <td class="tdr"></td> - <td class="tdr">3.30</td> - <td class="nobl"></td> - </tr> - <tr> - <td>After 48 Hours</td> - <td class="tdr">10.00</td> - <td class="tdr">30</td> - <td class="tdr">2</td> - <td class="tdr">14</td> - <td class="tdr">.20</td> - <td class="nobl"></td> - </tr> - <tr> - <td></td> - <td class="tdr"></td> - <td class="tdr"></td> - <td class="tdr"></td> - <td class="tdr"></td> - <td class="tdr">.20</td> - <td class="nobl"></td> - </tr> - <tr> - <td>After 72 Hours</td> - <td class="tdr">10.00</td> - <td class="tdr">30</td> - <td class="tdr">2</td> - <td class="tdr">8</td> - <td class="tdr">.18</td> - <td class="nobl"></td> - </tr> - <tr> - <td></td> - <td class="tdr"></td> - <td class="tdr"></td> - <td class="tdr"></td> - <td class="tdr"></td> - <td class="tdr">.08</td> - <td class="nobl"></td> - </tr> - <tr> - <td colspan="3" class="nw">Total times surely and possibly seen,—</td> - <td class="tdr nobl">6</td> - <td class="tdr nobl">41</td> - <td class="tdr"></td> - <td class="nobl"></td> - </tr> -</table> - -<p>Before entering upon a discussion of the facts shown by -these tables, we must describe the behavior of the imitators, -when, after seeing 2 pull the string, they were put in alone. -In the opinion of the present observer there was not the<span class="pagenum"><a id="Page_89"></a>[89]</span> -slightest difference between their behavior and that of cats -4, 10, 11, 12 and 13, who were put into the same position -without ever having seen 2 escape from it. 6, 7, 5 and 3 -paid no more attention to the string than they did, but -struggled in just the same way. No one, I am sure, who had -seen them, would have claimed that their conduct was at all -influenced by what they had seen. When they did hit the -string the act looked just like the accidental success of the -ordinary association experiment. But, besides these personal -observations, we have in the impersonal time-records -sufficient proofs of the absence of imitation. If the animals -pulled the string from having seen 2 do so, they ought -to pull it in each individual case at an approximately regular -length of time after they were put in, and presumably pretty -soon thereafter. That is, if an association between the sight -of that string in that total situation and a certain impulse -and consequent freedom and food had been formed in their -minds by the observation of the acts of 2, they ought to pull -it <i>on seeing it</i>, and if any disturbing factor required that a -certain time should elapse before the imitative faculty got -in working order, that time ought to be somewhere near -constant. The times were, as a fact, long and irregular in -the extreme. Furthermore, if the successful cases were -even in part due to imitation, the times ought to decrease -the more they saw 2 do the thing. Except with 3, they <i>increase</i> -or give place to failures. Whereas 6 and 7, if they -had been put in again immediately after their first successful -trial and from then on repeatedly, would have unquestionably -formed the association, they did not, when put in -after a further chance to increase their knowledge by imitation, -do the thing as soon as before. The case of 3 is not -here comparable to the rest because he <i>was</i> given three trials -in immediate succession. He was a more active cat and<span class="pagenum"><a id="Page_90"></a>[90]</span> -quicker to learn, as may be seen by comparing his time -curves with those of 7, 6 and 5. That the mere speed with -which he mastered this association is no sign that imitation -was present may be seen by reference to the time curves of -4 and 13 (on <a href="#Page_43">p. 43</a>).</p> - -<p>Some cats were also experimented with in the following -manner. They were put into a box [No. 7 into box A (O at -front), No. 5 into B (O at back)] and left for from 45 to 75 seconds. -Then a cat who knew the way to get out was put in, -and, of course, pulled at the loop and opened the door. <i>Both -cats then went out and both were fed.</i> After the cat had been -given a number of such chances to learn by imitation, he -was put in and left until he did the thing, or until 5 or 10 -minutes elapsed. As in the preceding experiments, no -change in their behavior which might signify imitation was -observed. No. 7 acted exactly like 3, or 10, or 11, when put -in the box, apparently forming the association by accident -in just the same way. Good evidence that he did not imitate -is the fact that, whereas 1 (whom he saw) pulled the -loop with his teeth, 7 pulled it with his paw. 5 failed to form -the association, though he saw 3 do it 8 times and probably -saw him 18 times more. He did get out twice by clawing -the <i>string</i> in the <i>front</i> of the box, not the <i>loop</i> in the <i>back</i>, -as 3 did. These successes took place early in the experiment. -After that he failed when left alone to get out at -all.</p> - -<p>Another experiment was made by a still different method. -My cats were kept in a large box about 4 ft. high, the front -of which was covered with poultry-yard netting. Its top -was a board which could be removed. To save opening the -door and letting them all loose, I was in the habit of taking -them out by the top when I wanted to experiment with -them. Of course the one who happened to climb up (perhaps<span class="pagenum"><a id="Page_91"></a>[91]</span> -attracted by the smell of fish on my fingers) was most -likely to be taken out and experimented with and fed. Thus -they formed the habit of climbing up the front of the box -whenever I approached. Of three cats which I obtained at -the same time, one did not after 8 or 10 days acquire this -habit. Even though I held out a piece of fish through the -netting, he would not climb after it. It was reasonable to -suppose that imitation might overcome this sluggishness, -if there were any imitation. I therefore put two cats with -him and had them climb up 80 times before his eyes and get -fish. He never followed or tried to follow them.</p> - -<p>4 and 3 had been subjected to the following experiment. -I would make a certain sound and after 10 seconds would go -up to the cage and hold the fish out to them through the -netting at the top. They would then, of course, climb up -and eat it. After a while, they began to climb up upon -hearing the signal (4) or before the 10 seconds were up. I -then took 12 and 10, who were accustomed to going up when -they saw me approach, but who had no knowledge of the -fact that the signal meant anything, and gave them each a -chance to imitate 3. That is, one of them would be left in -the box with 3, the signal would be given, and after from 5 -to 10 seconds 3 would climb up. At 10 seconds I would -come up with food, and then, of course, 12 would climb up. -This was repeated again and again. The question was -whether imitation would lead them to form the association -more quickly than they would have done alone. It did not. -That when at last they did climb up before 10 seconds -was past, that is, before I approached with food, it was not -due to imitation, is shown by the fact that on about half -of such occasions they climbed up <i>before 3 did</i>. That is, -they reacted to the <i>signal</i> by <i>association</i>, not to his <i>movements</i> -by <i>imitation</i>.</p> - -<p><span class="pagenum"><a id="Page_92"></a>[92]</span></p> - -<h3><span class="smcap">Imitation in Dogs</span></h3> - -<p>Here the method was not to see if imitation could arouse -more quickly an act which accident was fairly likely to bring -forth sooner or later, but to see if, where accident failed, -imitation would succeed.</p> - -<p>3 was found to be unable of himself to escape from box -BB1, and was then given a chance to learn from watching 1. -The back of box BB1 was torn off and wire netting substituted -for it. Another box with open front was placed directly -behind and against box BB1. No. 3, who was put in -this second box, could thus see whatever took place in and -in front of box BB1 (O at back, high). The record follows:—</p> - -<h4><span class="smcap">Table 6</span> (a)</h4> - -<table class="borders"> - <tr> - <th colspan="2"></th> - <th colspan="4"><span class="smcap">Dog 3 Imitating Dog 1</span></th> - </tr> - <tr> - <th></th> - <th>Times<br>1 did</th> - <th>Times<br>3 saw</th> - <th>Times<br>probably<br>3 saw</th> - <th colspan="2">Time<br>in alone</th> - </tr> - <tr> - <td></td> - <td class="tdr">30</td> - <td class="tdr">7</td> - <td class="tdr">14</td> - <td class="tdr">3.00</td> - <td class="nobl">F</td> - </tr> - <tr> - <td>After 1 Hour</td> - <td class="tdr">35</td> - <td class="tdr">9</td> - <td class="tdr">14</td> - <td class="tdr">3.00</td> - <td class="nobl">F</td> - </tr> - <tr> - <td>After 1 Hour</td> - <td class="tdr">10</td> - <td class="tdr">3</td> - <td class="tdr">3</td> - <td class="tdr">5.00</td> - <td class="nobl">F</td> - </tr> - <tr> - <td>After 24 Hours</td> - <td class="tdr">20</td> - <td class="tdr">6</td> - <td class="tdr">8</td> - <td class="tdr"></td> - <td class="nobl"></td> - </tr> - <tr> - <td></td> - <td class="tdr">30</td> - <td class="tdr">8</td> - <td class="tdr">13</td> - <td class="tdr">6.00</td> - <td class="nobl">F</td> - </tr> - <tr> - <td>After 48 Hours</td> - <td class="tdr">25</td> - <td class="tdr">8</td> - <td class="tdr">11</td> - <td class="tdr">8.00</td> - <td class="nobl">F</td> - </tr> - <tr> - <td></td> - <td class="tdr">25</td> - <td class="tdr">6</td> - <td class="tdr">12</td> - <td class="tdr">6.00</td> - <td class="nobl">F</td> - </tr> - <tr> - <td></td> - <td class="tdr">25</td> - <td class="tdr">9</td> - <td class="tdr">7</td> - <td class="tdr">10.00</td> - <td class="nobl">F</td> - </tr> - <tr> - <td>After 24 Hours</td> - <td class="tdr">30</td> - <td class="tdr">10</td> - <td class="tdr">11</td> - <td class="tdr">40.00</td> - <td class="nobl">F</td> - </tr> - <tr> - <td colspan="2" class="nw">Total times surely and possibly seen,—</td> - <td class="tdr nobl">66</td> - <td class="tdr nobl">93</td> - <td class="tdr"></td> - <td class="nobl"></td> - </tr> -</table> - -<p>A similar failure to imitate was observed in the case of -another simple act. No. 1, as may be seen on <a href="#Page_60">page 60</a>, -had learned to escape from a pen about 8 by 5 feet by jumping -up and biting a cord which ran from one end of the pen to -the other and at the front end was tied to the bolt which -held the door. Dogs 2 and 3 had failed in their accidental<span class="pagenum"><a id="Page_93"></a>[93]</span> -jumping and pawing to hit this cord, and were then given a -chance to learn by seeing 1 do so, escape, and, of course, be -fed. 1 always jumped in the same way, biting the cord at -the same place, namely, where a loose end from a knot in it -hung down 4 or 5 inches. 2 and 3 would either be tied up -in the pen or left in a pen at one side. They had a perfect -chance to see 1 perform his successful act. After every -twenty or thirty performances by 1, 2 and 3 would be put in -alone. It should be remembered that here, as also in the -previous experiment and all others, the imitators certainly -<i>wanted</i> to get out when thus left in alone. They struggled -and jumped and pawed and bit, but they never jumped <i>at -the cord</i>. Their records follow:—</p> - -<h4><span class="smcap">Table 6</span> (b)</h4> - -<table class="borders"> - <tr> - <th colspan="2"></th> - <th colspan="4"><span class="smcap">Dog 2 Imitating Dog 1</span></th> - </tr> - <tr> - <th></th> - <th>Times<br>1 did</th> - <th>Times<br>2 saw</th> - <th>Times<br>Doubtful</th> - <th colspan="2">Time 2 was<br>in alone</th> - </tr> - <tr> - <td></td> - <td class="tdr">30</td> - <td class="tdr">9</td> - <td class="tdr">11</td> - <td class="tdr">10.00</td> - <td class="nobl">F</td> - </tr> - <tr> - <td>After 1 Hour</td> - <td class="tdr">30</td> - <td class="tdr">10</td> - <td class="tdr">9</td> - <td class="tdr">10.00</td> - <td class="nobl">F</td> - </tr> - <tr> - <td>After 48 Hours</td> - <td class="tdr">25</td> - <td class="tdr">8</td> - <td class="tdr">8</td> - <td class="tdr"></td> - <td class="nobl"></td> - </tr> - <tr> - <td>After 1 Hour</td> - <td class="tdr">10</td> - <td class="tdr">3</td> - <td class="tdr">4</td> - <td class="tdr">9.00</td> - <td class="nobl">F<a id="FNanchor_11" href="#Footnote_11" class="fnanchor">[11]</a></td> - </tr> - <tr> - <td>After 24 Hours</td> - <td class="tdr">30</td> - <td class="tdr">8</td> - <td class="tdr">12</td> - <td class="tdr">15.00</td> - <td class="nobl">F</td> - </tr> - <tr> - <td>After 1 Hour</td> - <td class="tdr">30</td> - <td class="tdr">9</td> - <td class="tdr">12</td> - <td class="tdr">15.00</td> - <td class="nobl">F</td> - </tr> - <tr> - <td>After 48 Hours</td> - <td class="tdr">20</td> - <td class="tdr">7</td> - <td class="tdr">6</td> - <td class="tdr">10.00</td> - <td class="nobl">F</td> - </tr> - <tr> - <td></td> - <td class="tdr">20</td> - <td class="tdr">8</td> - <td class="tdr">7</td> - <td class="tdr"></td> - <td class="nobl"></td> - </tr> - <tr> - <td>After 48 Hours</td> - <td class="tdr">30</td> - <td class="tdr">6</td> - <td class="tdr">8</td> - <td class="tdr">15.00</td> - <td class="nobl">F</td> - </tr> - <tr> - <td>After 24 Hours</td> - <td class="tdr">15</td> - <td class="tdr">2</td> - <td class="tdr">4</td> - <td class="tdr">10.00</td> - <td class="nobl">F</td> - </tr> - <tr> - <td colspan="2" class="nw">Total times surely and possibly seen,—</td> - <td class="tdr nobl">70</td> - <td class="tdr nobl">81</td> - <td class="tdr"></td> - <td class="nobl"></td> - </tr> -</table> - -<p><span class="pagenum"><a id="Page_94"></a>[94]</span></p> - -<h4><span class="smcap">Table 6</span> (c)</h4> - -<table class="borders"> - <tr> - <th colspan="2"></th> - <th colspan="4"><span class="smcap">Dog 3 Imitating Dog 1</span></th> - </tr> - <tr> - <th></th> - <th>Times<br>1 did</th> - <th>Times<br>3 saw</th> - <th>Times<br>Doubtful</th> - <th colspan="2">Time 3 was<br>in alone</th> - </tr> - <tr> - <td></td> - <td class="tdr">30</td> - <td class="tdr">10</td> - <td class="tdr">10</td> - <td class="tdr">10.00</td> - <td class="nobl">F</td> - </tr> - <tr> - <td>After 1 Hour</td> - <td class="tdr">30</td> - <td class="tdr">9</td> - <td class="tdr">10</td> - <td class="tdr">10.00</td> - <td class="nobl">F</td> - </tr> - <tr> - <td>After 1 Hour</td> - <td class="tdr">15</td> - <td class="tdr">6</td> - <td class="tdr">4</td> - <td class="tdr"></td> - <td class="nobl"></td> - </tr> - <tr> - <td>After 24 Hours</td> - <td class="tdr">30</td> - <td class="tdr">9</td> - <td class="tdr">11</td> - <td class="tdr">15.00</td> - <td class="nobl">F</td> - </tr> - <tr> - <td>After 24 Hours</td> - <td class="tdr">30</td> - <td class="tdr">10</td> - <td class="tdr">12</td> - <td class="tdr">15.00</td> - <td class="nobl">F</td> - </tr> - <tr> - <td>After 1 Hour</td> - <td class="tdr">30</td> - <td class="tdr">8</td> - <td class="tdr">9</td> - <td class="tdr">10.00</td> - <td class="nobl">F</td> - </tr> - <tr> - <td>After 48 Hours</td> - <td class="tdr">20</td> - <td class="tdr">6</td> - <td class="tdr">7</td> - <td class="tdr">40.00</td> - <td class="nobl">F</td> - </tr> - <tr> - <td>After 1 Hour</td> - <td class="tdr">20</td> - <td class="tdr">6</td> - <td class="tdr">5</td> - <td class="tdr"></td> - <td class="nobl"></td> - </tr> - <tr> - <td>After 48 Hours</td> - <td class="tdr">30</td> - <td class="tdr">8</td> - <td class="tdr">9</td> - <td class="tdr">15.00</td> - <td class="nobl">F</td> - </tr> - <tr> - <td>After 24 Hours</td> - <td class="tdr">15</td> - <td class="tdr">3</td> - <td class="tdr">4</td> - <td class="tdr">20.00</td> - <td class="nobl">F</td> - </tr> - <tr> - <td colspan="2" class="nw">Total times surely and possibly seen,—</td> - <td class="tdr nobl">75</td> - <td class="tdr nobl">81</td> - <td class="tdr"></td> - <td class="nobl"></td> - </tr> -</table> - -<p>Another corroborative, though not very valuable, experiment -was the following: Dog 3 had been taught for the purpose -of another experiment to jump up on a box and beg -when I held a piece of meat above the box. I then caused -him to do this 110 times (within two days) in the presence of -1. Although 1 saw him at least 20 per cent of the times (3 -was always fed each time he jumped on the box), he never -tried to imitate him.</p> - -<p>It seems sure from these experiments that the animals -were unable to form an association leading to an act from -having seen the other animal, or animals, perform the act in -a certain situation. Thus we have further restricted the -association process. Not only do animals not have associations -accompanied, more or less permeated and altered, -by inference and judgment; they do not have associations -of the sort which may be acquired from other animals by -imitation. What this implies concerning the actual mental<span class="pagenum"><a id="Page_95"></a>[95]</span> -content accompanying their acts will be seen later on. It -also seems sure that we should give up imitation as an <i>a -priori</i> explanation of any novel intelligent performance. -To say that a dog who opens a gate, for instance, need not -have reasoned it out <i>if he had seen another dog do the same -thing</i>, is to offer, instead of one false explanation, another -equally false. Imitation in any form is too doubtful a -factor to be presupposed without evidence. And if a -general imitative faculty is not sufficiently developed to -succeed with such simple acts as those of the experiments -quoted, it must be confessed that the faculty is in these -higher mammals still rudimentary and capable of influencing -to only the most simple and habitual acts, or else -that for some reason its sphere of influence is limited to -a certain class of acts, possessed of some <i>qualitative difference</i> -other than mere simplicity, which renders them imitable. -The latter view seems a hard one to reconcile with a sound -psychology of imitation or association at present, without -resorting to instinct. Unless a certain class of acts are by -the innate mental make-up especially tender to the influence -of imitation, the theory fails to find good psychological -ground to stand on. The former view may very well be -true. But in any case the burden of proof would now seem -to rest upon the adherents to imitation; the promising -attitude would seem to be one which went without imitation -as long as it could, and that is, of course, until it surely found -it present.</p> - -<p>Returning to imitation considered in its human aspect, to -imitation as a transferred association in particular, we find -that here our analytical study of the animal mind promises -important contributions to general comparative psychology. -If it is true, and there has been no disagreement about it, -that the primates do imitate acts of such novelty and complexity<span class="pagenum"><a id="Page_96"></a>[96]</span> -that only this out-and-out kind of imitation can explain -the fact, we have located one great advance in mental -development. Till the primates we get practically nothing -but instincts and individual acquirement through impulsive -trial and error. Among the primates we get also acquisition -by imitation, one form of the increase of mental -equipment by tradition. The child may learn from the -parent quickly without the tiresome process of seeing for -himself. The less active and less curious may share the -progress of their superiors. The brain whose impulses -hitherto could only be dislodged by specific sense-impressions -may now have any impulse set agoing by the sight of -the movement to which it corresponds.</p> - -<p>All this on the common supposition that the primates <i>do</i> -imitate, that a monkey in the place of these cats and dogs -<i>would</i> have pulled the string. My apology for leaving the -matter in this way without experiments of my own is that -the monkey which I procured for just this purpose failed in -two months to become tame enough to be thus experimented -on. Accurate information about the nature and extent of -imitation among the primates should be the first aim of -further work in comparative psychology, and will be sought -by the present writer as soon as he can get subjects fit for -experiments.</p> - -<div class="blockquote"> - -<p>In a questionnaire which was sent to fifteen animal trainers, -the following questions were asked:—</p> - -<p>1. “If one dog was in the habit of ‘begging’ to get food and -another dog saw him do it ten or twenty times, would the second -dog then beg himself?”</p> - -<p>2. “In general is it easier for you to teach a cat or dog a trick -if he has seen another do it?”</p> - -<p>3. “In general do cats imitate each other? Do dogs? Do -monkeys?”</p> - -<p><span class="pagenum"><a id="Page_97"></a>[97]</span></p> - -<p>4. “Give reasons for your opinion, and please write all the -reasons you have.”</p> - -</div> - -<p>Five gentlemen (Messrs. R. C. Carlisle, C. L. Edwards, V. P. -Wormwood, H. S. Maguire and W. E. Burke) courteously responded -to my questionnaire. All are trainers of acknowledged -reputation. To these questions on imitation four replied.</p> - -<p>To the first question we find the following answers: (<i>a</i>) -“Most dogs would.” (<i>b</i>) “Yes; he will very likely do it. He -will try and imitate the other dog <i>generally</i>.” (<i>c</i>) “If a young -dog with the mother, it would be very apt to.... With -older dogs, it would depend very much upon circumstances.” -(<i>d</i>) “He would not.”</p> - -<p>To 2 the answers were: (<i>a</i>) “Very much easier.” (<i>b</i>) “It -is always easier if they see another one do it often.” (<i>c</i>) “This -would also depend on certain conditions. In teaching to jump -out of a box and in again, seeing another might help, but in -teaching something very difficult, I do not think it would be the -case.” (<i>d</i>) “It is not.”</p> - -<p>To 3 the answers were: (<i>a</i>) “Yes. Some. More than -either dogs or cats.” (<i>b</i>) “Yes. Yes. Yes.” (<i>c</i>) “In certain -things, yes; mostly in those things which are in compliance to -the laws of their own nature.” (<i>d</i>) “No. No. Yes, they are -born imitators.”</p> - -<p>The only definite answer to question 4 was: “Take a dog or -cat and close them up in a room and go in and out several times, -and you will find that they will go to the door and stand up on -their hind legs with front paws on the door knob and try to open -the door to get out. I could also give you a hundred more such -reasons.” This was given by (<i>b</i>).</p> - -<p>The replies to a test question, however, go to show that -these opinions regarding imitation may be mistaken. Question -8 was: “If you wanted to teach a cat to get out of a -cage by opening an ordinary thumb latch and then pushing -the door, would you take the cat’s paw and push down the -thumb piece with it and then push the door open with the<span class="pagenum"><a id="Page_98"></a>[98]</span> -paw, or would you just leave the cat inside until it learned -the trick itself?” The second is certainly the better way, -as will be seen in a later part of this paper, and pushing the -latch with the cat’s paw has absolutely no beneficial influence -on the formation of the association, yet (<i>a</i>) and (<i>b</i>) -both chose the first way, and (<i>c</i>) answered ambiguously. -Further, the only reason given is, of course, no reason at all. -It proves too much, for if there were such imitation as that, -my cats and dogs would surely have done the far simpler -things required of them. I cannot find that trainers -make any practical use of imitation in teaching animals -tricks, and on the whole I think these replies leave the matter -just where it was before. They are mere opinions—not -records of observed facts. It seems arrogant and may -seem to some unjustifiable thus to discard testimony, to -stick to a theory based on one’s own experiments in the face -of these opinions. If I had wished to gain applause and -avoid adverse criticism, I would have abstained from upholding -the radical view of the preceding pages. At times -it seems incredible to me that the results of my experiments -should embody the truth of the matter, that there -should be no imitation. The theory based on them seems, -even to me, too radical, too novel. It seems highly improbable -that I should be right and all the others wrong. But I -cannot avoid the responsibility of giving what seems to my -judgment the most probable explanation of the results of -the experiments; and that is the radical explanation already -given.</p> - -<h3><span class="smcap">The Mental Fact in Association</span></h3> - -<p>It is now time to put the question as to just what is in an -animal’s mind when, having profited by numerous experiences,<span class="pagenum"><a id="Page_99"></a>[99]</span> -he has formed the association and does the proper act -when put in a certain box. The commonly accepted view -of the mental fact then present is that the sight of the inside -of the box reminds the animal of his <i>previous pleasant experience -after escape</i> and <i>of the movements</i> which he made which -were immediately followed by and so associated with that -escape. It has been taken for granted that <i>if the animal -remembered the pleasant experience and remembered the movement, -he would make the movement</i>. It has been assumed -that the association was <i>an association of ideas</i>; that when -one of the ideas was of a movement the animal was capable -of making the movement. So, for example, Morgan says, in -the ‘Introduction to Comparative Psychology’: “If a chick -takes a ladybird in its beak forty times and each time finds -it nasty, this is of no practical value to the bird unless the -sight of the insect suggests <i>the nasty taste</i>” (p. 90).</p> - -<p>Again, on page 92, Morgan says, “<i>A race after the ball</i> had -been suggested through the channel of olfactory sensations.” -Also, on page 86 “... the visual impression suggested -the idea or representation of unpleasant gustatory experience.” -The attitude is brought out more completely in a -longer passage on page 118: “On one of our first ascents -one of them put up a young coney, and they both gave chase. -Subsequently they always hurried on to this spot, and, -though they never saw another coney there, reiterated disappointment -did not efface <i>the memory of that first chase</i>, or -so it seemed.” That is, according to Morgan, the dogs -thought of the chase and its pleasure, on nearing the spot -where it had occurred, and so hurried on. On page 148 of -‘Habit and Instinct,’ we read, “Ducklings so thoroughly -associated water with the sight of their tin that they tried -to drink from it and wash in it when it was empty, nor did -they desist for some minutes,” and this with other similar<span class="pagenum"><a id="Page_100"></a>[100]</span> -phenomena is attributed to the ‘association by contiguity’ -of human psychology.</p> - -<p>From these quotations it seems fairly sure that if we -should ask Mr. Morgan, who is our best comparative psychologist, -what took place in the mind of one of these cats -of our experiments during the performance of one of the -‘tricks’ he would reply: “The cat performs the act because -of the association of ideas. He is reminded by the sight of -the box and loop of his experience of pulling that loop and of -eating fish outside. So he goes and pulls it again.” This -view has stood unchallenged, but its implication is false. It -implies that an animal, whenever it thinks of an act, can -supply an <i>impulse to do</i> the act. It takes for granted -that the performance of a cat who gets out of a box is mentally -like that of a man who thinks of going down street -or of writing a letter and then does it. The mental process -is not alike in the two cases, for animals can <i>not</i> provide the -impulse to <i>do</i> whatever act they think of. <i>No cat can form -an association leading to an act unless there is included in the -association an impulse of its own which leads to the act.</i> There -is no general storehouse from which the impulse may be supplied -after the association is formed.</p> - -<p>Before describing the experiments which justify these -statements, it will be worth while to recall the somewhat obvious -facts about the composition of one of these associations. -There might be in an association, such as is formed -after experience with one of our boxes, the following elements:—</p> - -<p>1. Sense-impression of the interior of the box, etc.</p> - -<p>2. (<i>a</i>) Discomfort and (<i>b</i>) desire to get out.</p> - -<p>3. Representation of oneself pulling the loop.</p> - -<p>4. Fiat comparable to the human “I’ll do it.”</p> - -<p>5. The impulse which actually does it.</p> - -<p><span class="pagenum"><a id="Page_101"></a>[101]</span></p> - -<p>6. Sense-impression of oneself pulling the loop, seeing -one’s paw in a certain place, feeling one’s body in a certain -way, etc.</p> - -<p>7. Sense-impression of going outside.</p> - -<p>8. Sense-impression of eating, and the included pleasure.</p> - -<p>Also between 1 and 4 we may have 9, representations of -one’s experience in going out, 10, of the taste of the food, etc. -6, 7 and 8 come after the act and do not influence it, of -course, except in so far as they are the basis of the future -3’s, 9’s and 10’s. About 2 we are not at present disputing. -Our question is as to whether 3 or 5 is the essential thing. -In human associations 3 certainly often is, and the animals -have been credited with the same kind. Whatever he <i>thinks</i>, -Professor Morgan surely <i>talks</i> as if 1 aroused 9 and 10 and 3 -and leaves 5 to be supplied at will. We have affirmed that -5 is the essential thing, that no association without a specific -5 belonging to it and acquired by it can lead to an act. Let -us look at the reasons.</p> - -<p>A cat has been made to go into a box through the door, -which is then closed. She pulls a loop and comes out and -gets fish. She is made to go in by the door again, and again -lets herself out. After this has happened enough times, the -cat will of her own accord go into the box after eating the -fish. It will be hard to keep her out. The old explanation -of this would be that the cat associated the memory of being -in the box with the subsequent pleasure, and therefore performed -the equivalent of saying to herself, “Go to! I will -go in.” The thought of <i>being in</i>, they say, makes her <i>go in</i>. -<i>The thought of being in will not make her go in.</i> For if, instead -of pushing the cat toward the doorway or holding it -there, and thus allowing it to itself give the impulse, to innervate -the muscles, to walk in, you shut the door first and -drop the cat in through a hole in the top of the box, she will,<span class="pagenum"><a id="Page_102"></a>[102]</span> -after escaping as many times as in the previous case, <i>not</i> go -into the box of her own accord. She has had exactly the -same opportunity of connecting the idea of being in the box -with the subsequent pleasure. Either a cat cannot connect -ideas, representations, at all, or she has not the power of -progressing from the thought of being in to the act of going -in. The only difference between the first cat and the second -cat is that the first cat, in the course of the experience, -has the impulse to crawl through that door, while the second -has not the impulse to crawl through the door or to drop -through that hole. So, though you put the second cat on -the box beside the hole, she doesn’t try to get into the box -through it. The impulse is the <i>sine qua non</i> of the association. -The second cat has everything else, but cannot supply -that. These phenomena were observed in six cats, three -of which were tried by the first method, three by the -second. Of the first three, one went in himself on the 26th -time and frequently thereafter, one on the 18th and the other -on the 37th; the two last as well as the first did that frequently -in later trials. The other three all failed to go in -themselves after 50, 60 and 75 trials, respectively.</p> - -<p>The case of No. 7 was especially instructive, though not -among these six. No. 7 had had some trials in which it was -put in through the door, but ordinarily in this particular -experiment was dropped in. After about 80 trials it would -frequently exhibit the following phenomena: It would, -after eating the fish, go up to the doorway and, rushing -from it, search for fish. The kitten was very small and -would go up into the doorway, whirl round and dash out, -all in one quick movement. The best description of its -behavior is the paradoxical one that it went out without -going in. The association evidently concerned what it had -<i>done</i>, what it had an impulse for, namely, <i>coming out through<span class="pagenum"><a id="Page_103"></a>[103]</span> -that door</i> to get fish, not what it remembered, had a representation -of.</p> - -<p>Still more noteworthy evidence is found in the behavior of -cats and dogs who were put in these boxes, left one or two -minutes, and then put through the proper movement. -For example, a cat would be put in B (O at back) and left -two minutes. I would then put my hand in through the -top of the box, take the cat’s paw and with it pull down the -loop. The cat would then go out and eat the fish. This -would be done over and over again, and after every ten -or fifteen such trials the cat would be left in alone. If in -ten or twenty minutes he did not escape, he would be taken -out through the top and not fed. In one series of experiments -animals were taken and thus treated in boxes from -which their own impulsive activity had failed to liberate -them. The results, given in the table below, show that no -animal who fails to perform an act in the course of his own -impulsive activity will learn it by being put through it.</p> - -<p>In these experiments some of the cats and all of the dogs -but No. 1 showed no agitation or displeasure at my handling -from the very start. Nor was there any in Dog 1 or the other -cats after a few trials. It may also be remarked that in -the trials alone which took place during and at the end of -the experiment the animals without exception showed that -they did not fail to perform the act from lack of a desire to -get out. They all tried hard enough to get out and would -surely have used the association if they had formed it.</p> - -<p><span class="pagenum"><a id="Page_104"></a>[104]</span></p> - -<h4><span class="smcap">Table 7</span></h4> - -<table class="borders"> - <tr> - <th>Individual</th> - <th>Apparatus</th> - <th>Time in which impulsive activity failed to lead to the act</th> - <th>Number of times the animal was put through the movement</th> - <th>Time in which this experience failed to lead to the act</th> - <th>Time of final trial</th> - </tr> - <tr> - <td>Cat 1</td> - <td class="nw">F (String outside unfastened)</td> - <td class="tdr">55.00</td> - <td class="tdr">77</td> - <td class="tdr">120.00</td> - <td class="tdr">20.00</td> - </tr> - <tr> - <td>Cat 5</td> - <td>G (Thumb latch)</td> - <td class="tdr">57.00</td> - <td class="tdr">59</td> - <td class="tdr">55.00</td> - <td class="tdr">10.00</td> - </tr> - <tr> - <td>Cat 7</td> - <td>G (Thumb latch)</td> - <td class="tdr">50.00</td> - <td class="tdr">30</td> - <td class="tdr">35.00</td> - <td class="tdr">10.00</td> - </tr> - <tr> - <td>Cat 2</td> - <td>G (Thumb latch)</td> - <td class="tdr">54.00</td> - <td class="tdr">141</td> - <td class="tdr">110.00</td> - <td class="tdr">20.00</td> - </tr> - <tr> - <td>Dog 2</td> - <td>BB1 (O at back, high)</td> - <td class="tdr">48.00</td> - <td class="tdr">30</td> - <td class="tdr">80.00</td> - <td class="tdr">60.00</td> - </tr> - <tr> - <td>Dog 3</td> - <td>BB1 (O at back, high)</td> - <td class="tdr">20.00</td> - <td class="tdr">85</td> - <td class="tdr">55.00</td> - <td class="tdr">10.00</td> - </tr> - <tr> - <td>Dog 2</td> - <td>M (Lever outside)</td> - <td class="tdr">15.00</td> - <td class="tdr">95</td> - <td class="tdr">140.00</td> - <td class="tdr">30.00</td> - </tr> - <tr> - <td>Dog 1</td> - <td>FF<a id="FNanchor_12" href="#Footnote_12" class="fnanchor">[12]</a></td> - <td class="tdr">30.00</td> - <td class="tdr">110</td> - <td class="tdr">135.00</td> - <td class="tdr">60.00</td> - </tr> - <tr> - <td>Chick 89</td> - <td>X (see <a href="#Page_53">page 53</a>)</td> - <td class="tdr">20.00</td> - <td class="tdr">30</td> - <td class="tdr">60.00</td> - <td class="tdr">30.00</td> - </tr> - <tr> - <td>Cat 13</td> - <td>KKK,<a id="FNanchor_13" href="#Footnote_13" class="fnanchor">[13]</a><a id="FNanchor_14" href="#Footnote_14" class="fnanchor">[14]</a></td> - <td class="tdr">40.00</td> - <td class="tdr">65</td> - <td class="tdr">60.00</td> - <td class="tdr">10.00</td> - </tr> -</table> - -<p>Now, the only difference between the experiences of the -animals in these experiments and their experiences in those -where they let themselves out, is that here they only saw -and felt themselves making the movement, whereas in the -other case they also felt the impulse, gave the innervation. -That, then, is the essential. It may be objected that the -animals failed because they did not <i>attend</i> to the process -of being put through the movement, that, had they attended -to it, they would later themselves have made the movement. -It is, however, improbable that out of fifty times an animal -should not have attended to what was going on at least two -or three times. But if seeing himself do it was on a par with -feeling an impulse to and so doing it, even two or three -times would suffice to start the habit. And it is even more -improbable that an experience should be followed by keen -pleasure fifty times and not be attended to with might and<span class="pagenum"><a id="Page_105"></a>[105]</span> -main, unless animals attend <i>only</i> to their own impulses and -the excitements thereof. But if the latter be true, it simply -affirms our view from a more fundamental standpoint.</p> - -<p>In another set of experiments animals were put in boxes -with whose mechanisms they had had no experience, and -from which they might or might not be able to escape by -their own impulsive acts. The object was to see whether -the time taken to form the association could be altered by -my instruction. The results turned out to give a better -proof of the inability to form an association by being put -through the act than any failure to change the time-curve. -For it happened in all but one of the cases that the movement -which the animal made to open the door was different -from the movement which I had put him through. Thus, -several cats were put through (in Box C [button]) the following -movement: I took the right paw and, putting it against -the lower right-hand side of the button, pushed it round -to a horizontal position. The cats’ ways were as follows: -No. 1 turned it by clawing vigorously at its top; No. 6, -by pushing it round with his nose; No. 7, in the course of -an indiscriminate scramble at first, in later trials either by -pushing with his nose or clawing at the top, settling down -finally to the last method. Nos. 2 and 5 did it as No. 1 did. -Cat 2 was tried in B (O at back). I took his paw and pressed -the loop with it, but he formed the habit of clawing and -biting the string at the top of the box near the front. No. 1 -was tried in A. I pressed the loop with his paw, but he -formed the habit of biting at it.</p> - -<p>In every case I kept on putting the animal through the act -every time, if at the end of two minutes (one in several -cases) it had not done it, even after it had shown, by using -a different way, that my instruction had no influence. I -never succeeded in getting the animal to change its way for<span class="pagenum"><a id="Page_106"></a>[106]</span> -mine. Moreover, if any one should fancy that the animal -really profited by my instruction so as to learn what result -to attain, namely, the turning of a certain button, but -chose a way of his own to turn it, he would be deluding -himself. The time taken to learn the act with instruction -was no shorter than without.</p> - -<p>If, then, an animal happens to learn an act by being put -through it, it is just happening, nothing more. Of course, -you may <i>direct</i> the animal’s efforts so that he will perform -the act himself the sooner. For instance, you may hold -him so that his accidental pawing will be sure to hit the vital -point of the contrivance. But the animal cannot form -an association leading to an act unless the particular impulse -to that act is present as an element of the association; -he cannot supply it from a general stock. The groundwork -of animal associations is not the association of <i>ideas</i>, but -the association of idea or sense-impression with <i>impulse</i>.</p> - -<p>In the questionnaire mentioned elsewhere, some questions -were asked with a view to obtaining corroboration or refutation -of this theory that an impulse or innervation is a -necessary element in every association formed if that association -leads to an act. The questions and answers were:—</p> - -<p><i>Question 1</i>: “If you wanted to teach a horse to tap -seven times with his hoof when you asked him, ‘How many -days are there in a week?,’ would you teach him by taking -his leg and making him go through the motions?”</p> - -<p><i>A</i> answered, “Yes! at first.”</p> - -<p><i>B</i> answered, “No! I would not.”</p> - -<p><i>C</i> answered, “At first, yes!”</p> - -<p><i>D</i> answered, “No!”</p> - -<p><i>Question 2</i>: “Do you think you <i>could</i> teach him that way, -even if naturally you would take some other way?”</p> - -<p><i>A</i> answered, “In time, yes!”</p> - -<p><span class="pagenum"><a id="Page_107"></a>[107]</span></p> - -<p><i>B</i> answered, “I think it would be a very hard way.”</p> - -<p><i>C</i> answered, “Certainly I do.”</p> - -<p><i>D</i> answered, “I do not think I could.”</p> - -<p><i>E</i> answered, “Yes.”</p> - -<p><i>Question 3</i>: “How would you teach him?”</p> - -<p><i>A</i> answered, “I should tap his foot with a whip, so that -he would raise it, and reward him each time.”</p> - -<p><i>B</i> answered, “I should teach him by the motion of the -whip.”</p> - -<p><i>C</i> answered, “First teach him by pricking his leg the -number of times you wanted his foot lifted.”</p> - -<p><i>D</i> answered, “You put figure 2 on blackboard and touch -him on leg twice with cane, and so on.”</p> - -<p><i>E</i> answered ambiguously.</p> - -<p>It is noteworthy that even those who think they <i>could</i> -teach an animal by putting him through the trick do not -use that method, except at first. And what they really do -then is probably to stimulate the animal to the reflex act -of raising his hoof. The hand simply replaces the cane or -whip as the means of stimulus. The answers are especially -instructive, because the numerous counting tricks done by -trained horses seem, at first, to be incomprehensible, unless -the trainer can teach the horse by putting it through the -movement the proper number of times. The counting -tricks performed by Mascot, Professor Maguire’s horse, -were quoted to me by a friend as incomprehensible on my -theory. The answers given above show how simple the -thing really is. All the counting-tricks of all the intelligent -horses depend on the fact that a horse raises his hoof when -a certain stimulus is given. One simple reaction gives the -basis for a multitude of tricks. In the same way other -tricks, which at first sight seem to require that the animal -should learn by being put through the movement, may -depend on some simple reflex or natural impulse.</p> - -<p><span class="pagenum"><a id="Page_108"></a>[108]</span></p> - -<p>Another question was, “How would you teach a cat to -get out of a box, the door of which was closed with a thumb -latch?”</p> - -<p><i>A</i> answered, “I should use a puffball as a plaything for -the cat to claw at.” This means, I suppose, that he would get -the cat to claw at the puffball and thus direct its clawings -to the vicinity of the thumb piece.</p> - -<p><i>B</i> answered, “I would put the cat in and get it good and -hungry and then open the door by lifting the latch with my -finger. Then put some food that the cat likes outside, and -she will soon try to imitate you and so learn the trick.”</p> - -<p><i>C</i> answered, “I would first adjust all things in connection -with the surroundings of the cat so they would be applicable -to the laws of its nature, and then proceed to teach the -trick.”</p> - -<p>I suppose this last means that he would fix the box so that -some of the cat’s instinctive acts would lead it to perform -the trick. The answer given by <i>B</i> means apparently that -he would simply leave the thing to accident, for any such -imitation as he supposes is out of the question. At all -events, none of these would naturally start to teach the -trick by putting the animal through the motions, which, -were it a possible way, would probably be a traditional -one among trainers. On the whole, I see in these data no -reason for modifying our dogma that animals cannot learn -acts without the impulse.</p> - -<p>Presumably the reader has already seen budding out of -this dogma a new possibility, a further simplification of -our theories about animal consciousness. The possibility -is that animals may have <i>no images or memories at all, no -ideas to associate</i>. Perhaps the entire fact of association -in animals is the presence of sense-impressions with which -are associated, by resultant pleasure, certain impulses,<span class="pagenum"><a id="Page_109"></a>[109]</span> -and that, therefore, and therefore only, a certain situation -brings forth a certain act. Returning to our analysis of -the association, this theory would say that there was no (9) -or (10) or (3) or (4), that the sense-impression gave rise, -when accompanied by the feeling of discomfort, to the impulse -(5) directly, without the intervention of any representations -of the taste of the food, or the experience of being -outside, or the sight of oneself doing the act. This theory -might be modified so as to allow that the representations -could be there, but to deny that they were necessary, were -inevitably present, that the impulse was connected to the -sense-impression through them. It would then claim that -the effective part of the association was a direct bond between -the situation and the impulse, but would not cut off -the possibility of there being an aura of memories along with -the process. It then becomes a minor question of interpretation -which will doubtless sooner or later demand an -answer. I shall not try to answer it now. The more -radical question, the question of the utter exclusion of representative -trains of thought, of any genuine association -of <i>ideas</i> from the mental life of animals, is worth serious -consideration. I confess that, although certain authentic -anecdotes and certain experiments, to be described soon, -lead me to reject this exclusion, there are many qualities -in animals’ behavior which seem to back it up. If one takes -his stand by a rigid application of the law of parsimony, he -will find justification for this view which no experiments of -mine can overthrow.</p> - -<p>Of one thing I am sure, and that is that it is worth while -to state the question and how to solve it, for although the -point of view involved is far removed from that of our leading -psychologists to-day, it cannot long remain so. I am -sorry that I cannot pretend to give a final decision.</p> - -<p><span class="pagenum"><a id="Page_110"></a>[110]</span></p> - -<p>The view seems preposterous because, if an animal has -sense-impressions when his brain is excited by currents starting -in the end-organs, it seems incredible that he should not -be conscious in imagination and memory by having similar -excitations caused from within. We are accustomed to -think of memory as the companion of sensation. But, -after all, it is a question of fact whether the connections in -the cat brain include connections between present sensation-neuroses -and past sensation-neuroses. The only connections -may be those between the former and impulse-neuroses, -and there is no authoritative reason why we should -suppose any others unless they are demonstrated by the -cat’s behavior. This is just the point at issue. Such evidence -as the phenomena of animals’ dreams does not at all -prove the presence of memory or imagination. A dog may -very well growl in his sleep without any idea of a hostile -dog. The impulse to growl <i>may</i> be caused by chance excitement -of its own neurosis without any sensation-neurosis -being concerned. <i>Acts</i> of recognition may have no -<i>feelings</i> of recognition going with or causing them. A -sense-impression of me gets associated in my dog’s mind -with the impulses to jump on me, lick my hand, wag -his tail, etc. If, after a year, the connection between the -two has lasted, he will surely jump on me, lick my hand -and wag his tail, though he has not and never had any -representation of me.</p> - -<p>The only logical way to go at this question and settle it -is, I think, to find some associations the formation of which -requires the presence of images, of ideas. You have to give -an animal a chance to associate sense-impression A with -sense-impression B and then to associate B with some act -C so that the presence of B in the mind will lead to the -performance of C. Presumably the representation of B,<span class="pagenum"><a id="Page_111"></a>[111]</span> -if present, will lead to C just as the sense-impression B did. -Now, if the chance to associate B with A has been improved, -you ought, when the animal is confronted with the sense-impression -A, to get a revival of B and so the act C. Such -a result would, if all chance to associate C with A had been -eliminated, demonstrate the presence of representations -and their associations. I performed such an experiment -in a form modified so as to make it practicable with my -animals and resources. Unfortunately, this modification -spoils the crucial nature of the experiment and robs it of -much of its authority. The experiment was as follows:—</p> - -<p>A cat was in the big box where they were kept (see <a href="#Page_90">p. 90</a>) -very hungry. As I had been for a long time the source -of all food, the cats had grown to watch me very carefully. -I sat, during the experiment, about eight feet from the box, -and would at intervals of two minutes clap my hands four -times and say, “I must feed those cats.” Of course the -cat would at first feel no impulse except perhaps to watch me -more closely when this signal was given. After ten seconds -had elapsed I would take a piece of fish, go up to the cage -and hold it through the wire netting, three feet from the -floor. The cat would then, of course, feel the impulse to -climb up the front of the cage. In fact, experience had -previously established the habit of climbing up whenever -I moved toward the cage, so that in the experiment the -cat did not ordinarily wait until I arrived there with the -fish. In this experiment</p> - -<p>A = The sense-impression of my movements and voice -when giving the signal.</p> - -<p>B = The sense-impression of my movements in taking -fish, rising, walking to box, etc.</p> - -<p>C = The act of climbing up, with the impulse leading -thereunto.</p> - -<p><span class="pagenum"><a id="Page_112"></a>[112]</span></p> - -<p>The question was whether after a while A would remind -the cat of B, and cause him to do C before he got the <i>sense-impression</i> -of B, that is, before the ten seconds were up. If -A leads to C through a memory of B, animals surely <i>can</i> -have association of ideas proper, and probably often <i>do</i>. -Now, as a fact, after from thirty to sixty trials, the cat does -perform C immediately on being confronted by A or some -seconds later, at all events before B is presented. And it is -my present opinion that their action is to be explained by -the presence, through association, of the idea B. But it is -not impossible that A was associated <i>directly</i> with the impulse -to C, although that impulse was removed from it by -ten seconds of time. Such an association is, it seems to me, -highly improbable, unless the neurosis of A, and with it the -psychosis, continues until the impulse to C appears. But -if it does so continue during the ten seconds, and thus get -directly linked to C, we have exactly a representation, an -image, a memory, in the mind for eight of those ten seconds. -It does not help the deniers of images to substitute an image -of A for an image of B. Yet, unless they do this, they have -to suppose that A comes and goes, and that after ten seconds -C comes, and, passing over the intervening blank, -willfully chooses out A and associates itself with it. There -are some other considerations regarding the behavior of the -cats from the time the signal was given till they climbed up, -which may be omitted in the hope that it will soon be possible -to perform a decisive experiment. If an observer can -make sure of the animal’s attention to a sequence A-B, -where B does not arouse any impulse to an act, and then -later get the animal to associate B with C, leaving A out this -time, he may then, if A, when presented anew, arouses C, -bid the deniers of representations to forever hold their -peace.</p> - -<p><span class="pagenum"><a id="Page_113"></a>[113]</span></p> - -<p>Another reason for allowing animals representations and -images is found in the longer time taken to form the association -between the act of licking or scratching and the consequent -escape. If the associations in general were simply -between situation and impulse and act, one would suppose -that the situation would be associated with the impulse to -lick or scratch as readily as with the impulse to turn a button -or claw a string. Such is not the case. By comparing the -curves for Z on <a href="#Page_57">pages 57-58</a> with the others, one sees that for -so simple an act it takes a long time to form the association. -This is not a final reason, for lack of attention, a slight increase -in the time taken to open the door after the act was -done, or an absence of preparation in the nervous system -for connections between these particular acts and definite -sense-impressions, may very well have been the cause of the -difficulty in forming the associations. Nor is it certain that -<i>ideas</i> of clawing loops would be easier to form than ideas of -scratching or licking oneself. The matter is still open to -question. But, as said before, my opinion would be that -animals <i>do</i> have representations and that such are the -beginning of the rich life of ideas in man. For the most part, -however, such are confined to specific and narrow practical -lines. There was no evidence that my animals habitually -<i>did</i> form associations of ideas from their experience throughout, -or that such were constantly revived without the spur -of immediate practical advantage.<a id="FNanchor_15" href="#Footnote_15" class="fnanchor">[15]</a></p> - -<p><span class="pagenum"><a id="Page_114"></a>[114]</span></p> - -<p>Before leaving the topic an account may be given of experiments -similar to the one described above as performed -on Cats 3 and 4, which were undertaken with Cat 13 and -Dogs 1, 2 and 3.</p> - -<p>Cat 13 was fed with pieces of fish at the top of the wire -netting 45 times, to accustom it to climbing up when it saw<span class="pagenum"><a id="Page_115"></a>[115]</span> -me come with fish. I then went through the same process -as with 3 and 4, but at intervals of 60 to 90 seconds instead -of 120. After 90 such trials it occasionally climbed up a -little way, but though 135 trials in all were given, it never -made the uniform and definite reaction which 3 and 4 did. -It reacted, when it reacted at all, at from 5 to 9 seconds after -the signal. Whether age, weight, lack of previous habitual -climbing when I approached, or a slowness in forming the -association made the difference, is uncertain.</p> - -<p>Dog 1 was experimented on in the following manner: I -would put him in a big pen, 20×10 feet, and sit outside facing -it, he watching me as was his habit. I would pound with a -stick and say, “Go over to the corner.” After an interval -(10 seconds for 35 trials, 5 seconds for 60 trials) I would go -over to the corner (12 feet off) and drop a piece of meat -there. He, of course, followed and secured it. On the 6th,<span class="pagenum"><a id="Page_116"></a>[116]</span> -7th, 16th, 17th, 18th and 19th trials he did perform the act -before the 10 seconds were up, then for several times went -during the two-minute intervals without regarding the signal, -and finally abandoned the habit altogether, although -he showed by his behavior when the signal was given that -he was not indifferent to it.</p> - -<p>Dogs 1, 2 and 3 were also given 95, 135 and 95 trials, respectively, -the acts done being (1) standing up against the -wire netting inclosing the pen, (2) placing the paws on top of -a keg, and (3) jumping up onto a box. The time intervals -were 5 seconds in each case. No dog of these ever performed -the act before I started to take the meat to feed -them, but they did show, by getting up if they were lying -down when the signal was given, or by coming to me if they -were in some other part of the pen, that something was suggested -to them by it. Why these cases differ from the cases -of Cats 3 and 4 (10 and 12 also presented phenomena like -those reported in the cases of 3 and 4) is an interesting -though not very important question. The dogs were not -kept so hungry as were the cats, and experience had certainly -not rendered the particular impulses involved so -sensitive, so ready to discharge. Dogs 2 and 3 were older. -There is no reason to invoke any qualitative difference in the -mental make-up of the animals until more illuminating experiments -are made.</p> - -<h3><span class="smcap">Association by Similarity and the Formation of Concepts</span></h3> - -<p>What there is to say on this subject from the standpoint of -my experiments will be best introduced by an account of -the experiments themselves.</p> - -<p>Dog 1 had escaped from AA (O at front) 26 times. He<span class="pagenum"><a id="Page_117"></a>[117]</span> -was then put in BB (O at back). Now, whereas 2 and 3, who -were put in without previous experience with AA, failed to -paw the loop in BB, No. 1 succeeded. His times were 7.00, -.35, 2.05, .40, .32, .10, 1.10, .38, .10, .05, and from then on he -pawed the loop as soon as put in the box. After a day or so -he was put in BB1 (O at back high). Although the loop -was in a new position, his times were only .20, .10, .10, etc. -After nine days he was put in a box arranged with a little -wooden platform 2½ inches square, hung where the loop was -in BB1. Although the platform resembled the loop not -the least save in position, his times were only .10, .07, .05, -etc.</p> - -<div class="figcenter illowp100" id="figure21" style="max-width: 28.125em;"> - <img class="w100" src="images/figure21.jpg" alt=""> - <p class="caption"><span class="smcap">Fig. 21.</span></p> -</div> - -<p>From the curves given in <a href="#figure21">Figure 21</a>, which tell the history -of 10, 11 and 12 in B1 (O at back) after each had previously -been familiarized with A (O at front), we see this same -influence of practice in reacting to one mechanism upon the -time taken to react to a mechanism at all similar. It naturally -takes a cat a longer time to accidentally claw a loop in -the back than in the front, yet a comparison of these curves -with those on page 39, <a href="#figure02">Figure 2</a>, shows the opposite to have -been the case with 10, 11 and 12. The same remarkable<span class="pagenum"><a id="Page_118"></a>[118]</span> -quickness was noted in Cats 1 and 3 when put into B (O at -back) after learning A (O at front). Moreover, the loops -were not alike. The loop in A was of smaller wire, covered -with a bluish thread, while the loop in B was covered with -a black rubber compound, the diameter of the loop being -three times that of A’s loop.</p> - -<p>If any advocate of reason in animals has read so far, I -doubt not that his heart has leaped with joy at these two -preceding paragraphs. “How,” he will say, “can you explain -these facts without that prime factor in human reason, -association by similarity? Surely they show the animal -perceiving likenesses and acting from general ideas.” <i>This -is the very last thing that they show.</i> Let us see why they do -not show this and what they do show. He who thinks that -these animals had a general notion of a loop-like thing as the -thing to be clawed, that they felt the loop in B, different -as it was in size, color and position, to be still a loop, to -have the essential quality of the other, must needs presuppose -that the cat has a clear, accurate sensation and -representation of both. Only if the cat discriminates can -it later associate by noticing similarities. This is what such -thinkers do presuppose. A bird, for instance, dives in the -same manner into a river of yellow water, a pond or an ocean. -It has a general notion, they say, of water. It knows that -river water is one thing and pond water another thing, but it -knows that both are water, <i>ergo</i>, fit to dive into. The cat -who reacts to a loop of small wire of a blue color knows -just what that loop is, and when it sees a different loop, -knows its differences, but knows also its likeness, and reacts -to the essential. Thus crediting the cat with our differentiation -and perception of individuality, they credit it with -our conceptions and perceptions of similarity. Unless the -animal has the first, there is no reason to suppose the last.<span class="pagenum"><a id="Page_119"></a>[119]</span> -Now, <i>the animal does not have either</i>. It does not in the first -place react to that particular loop in A, with recognition of -its qualities. It reacts to a vague, ill-defined sense-impression, -undiscriminated and even unperceived in the technical -sense of the word. Morgan’s phrase, “a bit of pure experience,” -is perhaps as good as any. The loop is to the cat -what the ocean is to a man, when thrown into it when half-asleep. -Thus the cat who climbed up the front of the cage -whenever I said, “I must feed those cats,” would climb up -just as inevitably when I said, “My name is Thorndike,” -or “To-day is Tuesday.” So cats would claw at the loop -or button when the door was open. So cats would paw at -the place where a loop had been, though none was there. -The reaction is not to a well-discriminated object, but to a -vague situation, and any element of the situation may -arouse the reaction. The whole situation in the case of man -is speedily resolved into elements; the particular elements -are held in focus, and the non-essential is systematically kept -out of mind. In the animal the whole situation sets loose -the impulse; all of its elements, including the non-essentials, -get yoked with the impulse, and the situation may be -added to or subtracted from without destroying the association, -provided you leave something which will set off -the impulse. The animal does not think one is like the other, -nor does it, as is so often said, mistake one for the other. It -does not think <i>about</i> it at all; it just thinks <i>it</i>, and the <i>it</i> is -the kind of “pure experience” we have been describing. In -human mental life we have accurate, discriminated sensations -and perceptions, realized as such, and general notions, -also realized as such. Now, what the phenomena in animals -which we have been considering show is that they -have neither. Far from showing an advanced stage of mentality, -they show a very primitive and unspecialized stage.<span class="pagenum"><a id="Page_120"></a>[120]</span> -They are to be explained not by the presence of <i>general</i> notions, -but by the absence of notions of <i>particulars</i>. The -idea that animals react to a particular and absolutely defined -and realized sense-impression, and that a similar -reaction to a sense-impression which varies from the first -proves an association by similarity, is a myth. We shall see -later how an animal does come in certain cases to discriminate, -in one sense of the word, with a great degree of delicacy, -but we shall also see then what must be emphasized -now, that naturally the animal’s brain reacts very coarsely -to sense-impressions, and that the animal does not think -about his thoughts at all.</p> - -<p>This puts a new face upon the question of the origin and -development of human abstractions and consequent general -ideas. It has been commonly supposed that animals had -‘recepts’ or such semi-abstractions as Morgan’s ‘predominants,’ -and that by associating with these, arbitrary and permanent -signs, such as articulate sounds, one turned them -into genuine ideas of qualities. Professor James has made -the simple but brilliant criticism that all a recept really -means is <i>a tendency to react in a certain way</i>. But I have -tried to show that the fact that an animal reacts alike to a lot -of things gives no reason to believe that it is conscious of -their common quality and reacts to that consciousness, because -the things it reacts to in the first place are not the -hard-and-fast, well-defined ‘things’ of human life. What -a ‘recept’ or ‘predominant’ really stands for is no thing -which can be transformed into a notion of a quality by -being labelled with a name. This easy solution of the -problem of abstraction is impossible. A true idea of the -problem itself is better than such a solution.</p> - -<p>My statement of what has been the course of development -along this line is derived from observations of animals’<span class="pagenum"><a id="Page_121"></a>[121]</span> -behavior and Professor James’ theory of the nature of and -presumable brain processes going with the abstractions and -conceptions of human consciousness, but it is justified chiefly -by its harmony with the view that conception, the faculty -of having general notions, has been naturally selected by -reason of its utility. The first thing is for an animal to learn -to react alike only to things which resemble each other in the -<i>essential</i> qualities. On an artificial, analytic basis, feelings -of abstract qualities might grow out of reacting alike to objects -similar in such a respect that the reaction would be -useless or harmful. But in the actual struggle for existence, -starting with the mammalian mind as we have found it, -you will tend to get reactions to the <i>beneficial</i> similarities -by selection from among these so-called mistakes, <i>before -you get any general faculty of noticing similarities</i>. In -order that this faculty of indifferent reaction to different -things shall grow into the useful faculty of indifferent reaction -to different things <i>which have all some quality that makes -the reaction a fit one</i>, there must be a tremendous range of -associations. For a lot of the similarities which are non-essential -have to be stamped out, not by a power of feeling -likeness, but by their failure to lead to pleasure. With -such a wide range of associations we may get reactions on -the one hand where impulses have been connected with one -particular sense-impression because when connected with -all others they had failed to give pleasure, and on the other -hand, reactions where an impulse has been connected with -numerous different impressions possessing one common -quality, and disconnected with all impressions, otherwise -like these, which fail to have that one quality.</p> - -<p>Combined with this multiplication of associations, there is, -I think, an equally important factor, the loosening of the -elements of an association from one another and from it as a<span class="pagenum"><a id="Page_122"></a>[122]</span> -whole. Probably the idea of the look of the loop or lever or -thumb latch never entered the mind of any one of my cats -during the months that they were with me, except when the -front end of the association containing it was excited by putting -the cat into the box. In general, the unit of their consciousness, -apart from impulses and emotions, is a whole -association-series. Such soil cannot grow general ideas, for -the ideas, so long as they never show themselves except for -a particular practical business, will not be thought about or -realized in their nature or connections. If enough associations -are provided by a general curiosity, such as is seen -among the monkeys, if the mental elements of the association -are freed, isolated, felt by themselves, <i>then</i> a realization -of the ideas, feelings of their similarity by transition from -one to the other, feelings of qualities and of meanings, may -gradually emerge. Language will be a factor in the isolation -of the ideas and a help to their realization. But when -any one says that language has been the cause of the change -from brute to man, when one talks as if <i>nothing but it</i> were -needed to turn animal consciousness into human, he is speaking -as foolishly as one who should say that a proboscis added -to a cow would make it an elephant.</p> - -<p>This is all I have to say, in this connection, about association -by similarity and conception, and with it is concluded -our analysis of the nature of the association-process in animals. -Before proceeding to treat of the delicacy, complexity, -number and permanence of these associations, it -seems worth while to attempt to describe graphically, not by -analysis, the mental fact we have been studying, and also -to connect our results with the previous theories of association.</p> - -<p>One who has seen the phenomena so far described, who -has watched the life of a cat or dog for a month or more<span class="pagenum"><a id="Page_123"></a>[123]</span> -under test conditions, gets, or fancies he gets, a fairly definite -idea of what the intellectual life of a cat or dog feels -like. It is most like what we feel when consciousness contains -little thought about anything, when we feel the sense-impressions -in their first intention, so to speak, when we feel -our own body, and the impulses we give to it. Sometimes -one gets this animal consciousness while in swimming, for -example. One feels the water, the sky, the birds above, but -with no thoughts <i>about</i> them or memories of how they looked -at other times, or æsthetic judgments about their beauty; -one feels no <i>ideas</i> about what movements he will make, but -feels himself make them, feels his body throughout. Self-consciousness -dies away. Social consciousness dies away. -The meanings, and values, and connections of things die -away. One feels sense-impressions, has impulses, feels the -movements he makes; that is all.</p> - -<p>This pictorial description may be supplemented by an account -of some associations in human life which are learned in -the same way as are animal associations; associations, therefore, -where the process of formation is possibly homologous -with that in animals. When a man learns to swim, to play -tennis or billiards, or to juggle, the process is something like -what happens when the cat learns to pull the string to get -out of the box, provided, of course, we remove, in the man’s -case, all the accompanying mentality which is not directly -concerned in learning the feat.<a id="FNanchor_16" href="#Footnote_16" class="fnanchor">[16]</a> Like the latter, the former<span class="pagenum"><a id="Page_124"></a>[124]</span> -contains desire, sense-impression, impulse, act and possible -representations. Like it, the former is learned gradually. -Moreover, the associations concerned cannot be formed -by imitation. One does not know how to dive just by seeing -another man dive. You cannot form them from being -put through them, though, of course, this helps indirectly, -in a way that it does not with animals. One makes use of -no feelings of a common element, no perceptions of similarity. -The tennis player does not feel, “This ball coming -at this angle and with this speed is similar in angle, though -not in speed, to that other ball of an hour ago, therefore I -will hit it in a similar way.” He simply feels an impulse -from the sense-impression. Finally, the elements of the -associations are not isolated. No tennis player’s stream of -thought is filled with free-floating representations of any -of the tens of thousands of sense-impressions or movements -he has seen and made on the tennis court. Yet there -is consciousness enough at the time, keen consciousness of -the sense-impressions, impulses, feelings of one’s bodily acts. -So with the animals. There is consciousness enough, but -of this kind.</p> - -<p>Thus, the associations in human life, which compare with -the simple connections learned by animals, are associations -involving connections between novel, complex and often -inconstant sense-impressions and impulses to acts similarly -novel, complex and often inconstant. Man has the elements -of most of his associations in isolated form, attended -to separately, possessed as a permanent fund, recallable at -will, and multifariously connected among themselves, but<span class="pagenum"><a id="Page_125"></a>[125]</span> -with these associations which we have mentioned, and with -others like them, he deals as the animals deal with theirs. -The process, in the man’s mind, leaving out extraneous mental -stuff, may be homologous to the association-process in -animals. Of course, by assiduous attention to the elements -of these associations, a man may isolate them, may thus get -these associations to the same plane as the rest. But they -pass through the stage we have described, even then, and -with most men, stay there. The abstraction, the naming, -etc., generally come from observers of the game or action, -and concern things as felt by them, not by the participant.</p> - -<h3><span class="smcap">Criticism of Previous Theories</span></h3> - -<p>We may now look for a moment at what previous writers -have said about the nature of association in animals. The -complaint was made early in this book that all the statements -had been exceedingly vague and of no value, except as -retorts to the ‘reason’ school. In the course of the discussion -I have tried to extricate from this vagueness definite -statements about imitation, association of ideas, association -by ideas. There is one more theory, more or less hidden in -the vagueness,—the theory that association in animals is the -same as association in man, that the animal mind differs -from the human mind only by the absence of reason and -what it implies. Presumably, silence about what association -is, means that it is the association which human psychology -discusses. When the silence is broken, we get such -utterances of this theory as the following:—</p> - -<p>“I think we may say then that the higher animals are able -to proceed a long way in the formation and definition of -highly complex constructs, analogous to but probably differing -somewhat from those which we form ourselves. These<span class="pagenum"><a id="Page_126"></a>[126]</span> -constructs, moreover, through association with reconstructs, -or representations, link themselves in trains so that a sensation, -or group of sensations, may suggest a series of reconstructs, -or a series of remembered phenomena.” (C. L. -Morgan, Animal Life and Intelligence, p. 341.)</p> - -<p>“Lastly, before taking leave of the subject of the chapter, -I am most anxious that it should not be thought that, in contending -that intelligence is not reason, I wish in any way to -disparage intelligence. Nine tenths at least of the actions of -average men are intelligent and not rational. Do we not all -of us know hundreds of practical men who are in the highest -degree intelligent, but in whom the rational, analytic -faculty is but little developed? Is it any injustice to the -brutes to contend that their inferences are of the same order -as those of these excellent practical folk? In any case, no -such injustice is intended; and if I deny them self-consciousness -and reason, I grant to the higher animals perceptions -of marvelous acuteness and intelligent inferences of wonderful -accuracy and precision—intelligent inferences in -some cases, no doubt, more perfect even than those of man, -who is often disturbed by many thoughts” (<i>ibid.</i>, pp. 376-377).</p> - -<p>“Language and the analytic faculty it renders possible -differentiate man from the brute” (<i>ibid.</i>, p. 376).</p> - -<p>Here, as elsewhere, it should be remembered that Lloyd -Morgan is not quoted because he is the worst offender or because -he represents the opposite in general of what the present -writer takes to be the truth. On the contrary, Morgan -is quoted because he is the least offender, because he -has taken the most advanced stand along the line of the -present investigation, because my differences from him are -in the line of his differences from other writers. With the -theory of the passages just quoted, however, which attribute<span class="pagenum"><a id="Page_127"></a>[127]</span> -extensive association of ideas and general powers comparable -to those of men minus reason, to the brutes, and which -repeat the time-honored distinction by language, I do not, -in the least, agree. Association in animals does not equal -association in man. The latter is built over and permeated -and transformed by inference and judgment and comparison; -it includes imitation in our narrow sense of transferred -association; it obtains where no impulse is included; it -thus takes frequently the form of long trains of thought -ending in no pleasure-giving act; its elements are often -loose, existing independently of the particular association; -the association is not only thought, but at the same time -thought <i>about</i>. None of these statements may be truthfully -made of animal association. Only a small part of human -association is at all comparable to it. My opinion of what -that small part is has already been given. Moreover, -further differences will be found as we consider the data -relating to the delicacy, complexity, number, and permanence -of associations in animals. I said a while ago that -man was no more an animal with language than an elephant -was a cow with a proboscis. We may safely broaden -the statement and say that <i>man is not an animal plus reason</i>. -It has been one great purpose of this investigation -to show that even after leaving reason out of account, -there are tremendous differences between man and the -higher animals. The problem of comparative psychology is -not only to get human reason from some lower faculties, -but to get human <i>association</i> from animal association.</p> - -<p>Our analysis, necessarily imperfect because the first attempted, -of the nature of the association-process in animals -is finished, and we have now to speak of its limitations in -respect to delicacy, complexity, number and permanence.</p> - -<p><span class="pagenum"><a id="Page_128"></a>[128]</span></p> - -<h3><span class="smcap">Delicacy of Associations</span></h3> - -<p>It goes without saying that the possible delicacy of associations -is conditioned by the delicacy of sense-powers. If -an animal doesn’t feel differently at seeing two objects, it -cannot associate one with one reaction, the other with another. -An equally obvious factor is attention; what is not -attended to will not be associated. Beyond this there is no -<i>a priori</i> reason why an animal should not react differently -to things varying only by the most delicate difference, and -I am inclined to think an animal could; that any two objects -with a difference appreciable by sensation which are -also able to win attention may be reacted to differently. -Experiments to show this are very tedious, and the practical -question is, “What will the animal naturally attend to?” -The difficulty, as all trainers say, is to get the animal’s -attention to your signal somehow. Then he will in time -surely react differently, if you give him the chance, to a -figure 7 on the blackboard from the way he does to a figure -8, to your question, “How many days are there in a week?” -and to your question, “How many legs have you?” The -chimpanzee in London that handed out 3, 4, 5, 6, or 7 straws -at command was not thereby proved of remarkable intelligence -or of remarkably delicate associative power. Any -reputable animal trainer would be ashamed to exhibit a -horse who could not do as much ‘counting’ as that. The -maximum of delicacy in associating exhibited by any animal, -to my knowledge, is displayed in the performance of the dog -‘Dodgerfield,’ exhibited by a Mr. Davis, who brings from -four cards, numbered 1, 2, 3 and 4, whichever one his master -shall <i>think of</i>. That is, you write out an arbitrary list, e.g. -4, 2, 1, 3, 3, 2, 2, 1, 4, 2, etc., and hand it to Mr. Davis, who -looks at the list, thinks of the first number, says “Attention!<span class="pagenum"><a id="Page_129"></a>[129]</span> -Dodger!” and then, “Bring it.” This the dog does and so -on through the list. Mr. Davis makes no signals which anyone -sitting even right beside or in front of him can detect. -Thus the dog exceeds the human observers in delicacy and -associates each with a separate act four attitudes of his master, -which to human observers seem all alike. Mr. Davis -says he thinks the dog is a mind reader. I think it quite -possible that whatever signs the dog goes by are given unconsciously -and consist only of some very delicate general -differences in facial expression or the manner of saying the -words, “Bring it,” or slight sounds made by Mr. Davis in -thinking to himself the words one or two or three or four. -Mr. Davis keeps his eyes shut and his hands behind a newspaper. -The dog looks directly at his face.</p> - -<p>To such a height possible delicacy may attain, but possible -delicacy is quite another thing from actual untrained and -unstimulated delicacy. The difference in reaction has to be -brought about by associating with pleasure the reaction -to the different sense-impression when it itself differs and -associating with pain tendencies to confuse the reactions. -The animal does not naturally as a function of sense-powers -discriminate at all delicately. Thus the cat who climbed -up the wire netting when I said, “I must feed those cats!” -did not have a delicate association of just that act with just -those words. For after I had dropped the clapping part -of the signal and simply used those words, it would react just -as vigorously to the words, “To-morrow is Tuesday” or -“My name is Thorndike.” The reaction naturally was to -a very vague stimulus. Taking cat 10 when just beginning -to learn to climb up at the signal, “I must feed those cats!” -I started in to improve the delicacy, by opposing to this -formula the formula, “I will not feed them,” after saying -which, I kept my word. That is, I gave sometimes the<span class="pagenum"><a id="Page_130"></a>[130]</span> -former signal and fed the cats, sometimes the latter and did -not. The object was to see how long the cat would be in -learning always to go up when I gave the first, never to do -so when I gave the second signal. I said the words in both -cases as I naturally would do, so that there was a difference -in emphasis and tone as well as in the mere nature of the -syllables. The two signals were given in all sorts of combinations -so that there was no regularity in the recurrence of -either which might aid the animal. The cat at first did -not always climb up at the first signal and often <i>did</i> climb -up at the wrong one. The change from this condition to -one of perfect discrimination is shown in the accompanying -curves (<a href="#figure22">Fig. 22</a>), one showing -the decrease in <i>failures</i> -to respond to the -wrong signal. The first -curve is formed by a line -joining the tops of perpendiculars erected at intervals of -1 mm. along the abscissa. The height of a perpendicular -represents the number of times the cat failed to respond -to the food-signal in 20 trials, a height of 1 mm. being the -representative of one failure. Thus, the entire curve -stands for 280 trials, there being no failures after 60 trials, -and only 1 after the 40th.</p> - -<div class="figcenter illowp100" id="figure22" style="max-width: 18.75em;"> - <img class="w100" src="images/figure22.jpg" alt=""> - <p class="caption"><span class="smcap">Fig. 22.</span></p> -</div> - -<p>In the other curve, also, each 1 mm. along the abscissa -stands for 20 trials, and the perpendiculars whose tops the -curve unites represent the number of times the cat in each -20 <i>did</i> climb up at the signal which meant no food. It will -be seen that 380 experiences were necessary before the animal -learned that the second signal was different from the -first. The experiment shows beautifully the animal method -of acquisition. If at any stage the animal could have -isolated the two ideas of the two sense-impressions, and felt<span class="pagenum"><a id="Page_131"></a>[131]</span> -them together in comparison, this long and tedious process -would have been unnecessary.</p> - -<p>It might be stated here that the animals also acquired -associations of moderate delicacy in discriminating between -the different boxes. No cat tried to get out of A or B by -licking herself, for instance.</p> - -<p>The question may naturally be raised that if naturally -associations are thus vague, the common phenomenon of a -dog obeying his master’s commands, and no one else’s, is -inexplicable. The difference between one man and another, -one voice and another, it may be said, is not much of a difference, -yet is here uniformly discriminated, although we -cannot suppose any such systematic training to reject the -other slightly differing commands. My cats did not so -discriminate. If any one else sat in my chair and called -out, “I must feed the cats,” they reacted, and probably very -many animals would, if untroubled by emotions of curiosity -or fear at the new individual, go through their tricks as well -at another’s voice as at that of their master. The other -cases exemplify the influence of attention. Repeated -attention to these sense-impressions has rendered them -clear-cut and detailed, and the new impression consequently -does not equal them in calling forth the reaction.</p> - -<p>The main thing to carry away from this discussion is -the assurance that the delicacy of the animal in associating -acts with impressions is nothing like the delicacy of the man -who feels that a certain tone is higher, or weight is heavier, -than another, but <i>is</i> like the delicacy of the man who runs -to a certain spot to hit one tennis ball and to a different spot -to hit one coming with a slightly different speed.</p> - -<p><span class="pagenum"><a id="Page_132"></a>[132]</span></p> - -<h3><span class="smcap">Complexity of Associations</span></h3> - -<p>An important question, especially if one wishes to rate an -animal on a scale of intelligence, is the question of how complex -an association it can form. A man can learn that to -open a door he has to put the key in its hole, turn it, turn -the knob, and pull the door. Here, then, is a complex act -connected with the simple sense-impression. Or, conversely, -a man knows that when the ringing of a bell is -followed by a whistle and that by a red light he is to do a -certain thing, while if any of the three happens alone, he is -not to. How far, then, we ask, can animals go along the -line of increased complexity in the associations?</p> - -<p>We must not mistake for a complex association a series -of associations, where one sense-impression leads to an act -such as to present a new sense-impression which leads to -another act which in its turn leads to a new sense-impression. -Of the formation of such <i>series</i> animals are capable to a -very high degree. Chicks from 10 to 25 days old learned to -go directly through a sort of big labyrinth requiring a series -of 23 distinct and in some cases fairly difficult associations, -of which 11 involved choices between two paths. By this -power of acquiring a long series animals find their way to -distant feeding grounds and back again. But all such cases -are examples of the <i>number</i>, not of the complexity, of animal -associations.</p> - -<p>Some of my boxes were such as did give a chance for a -complex association to be formed. Such were G (thumb -latch), J (double), K and L (triples) for the cats, and O (triple) -for the dogs. It would be possible for a cat, after stepping -on the platform in K, to notice that the platform was in a -different position, and so feel then a different sense-impression -from before, and thus turn the thing into a serial association.<span class="pagenum"><a id="Page_133"></a>[133]</span> -The cat would then be like a man who on seeing -a door should feel only the impulse to stick the key in the -hole, but then, seeing the door plus a key in the hole, should -feel the impulse to turn the key and so on through. My -cats did not give any signs of this, so that with them it was -either a complex association or an irregular happening of -the proper impulses. Probably the same was the case with -Dog 1. Cats 10, 11, 12 in L knew all the movements -separately before being experimented on with the combination. -Cats 2, 3, 4 had had some experience of D, which -worked by a string something like the string part of K. The -string in K was, however, quite differently situated and -required an altogether different movement to pull it. Since -further No. 2, who had had ten times as much experience -in D as 3 or 4, succeeded no better with the string element -of K than they, it is probable that the experience did not -help very much. All else in all these compound associations -was new. At the same time the history of these animals’ -dealings with these boxes would not fairly represent that of -animals without general experience of clawing at all sorts -of loose or shaky things in the inside of a box. These -cats had learned to claw at all sorts of things. The -time-curves were taken as in the formation of the other -associations, and, in addition, the order in which the animal -did the several things required was recorded in every trial.</p> - -<p>In the case of all the curves, except the latter part of 3 -in G, one notices a very gradual slope and an excessive -irregularity in the curve throughout. Within the limits -of the trials given the animals are unable to form a perfect -association and what advancement they make is very slow. -The case of 3 in G is not an exception to this, but a proof of -it. For 3 succeeded in making a perfect association, by -accidentally hitting on a way to turn the compound association<span class="pagenum"><a id="Page_134"></a>[134]</span> -into a simple one. He happened one time to paw -down the thumb piece at the same time that his other -fore limb, with which he was holding on between the door -and the top of the box, was pressing against the door. -This giving him success he repeated it in later trials and in a -short time had it fixed as an element in a perfect association. -The marked change in his curve, from an irregular and gradual -slope at such a height as displayed a very imperfect -association, to a constant and very slight height, shows precisely -the change from a compound to a simple association.</p> - -<p>Compound associations are formed slowly and not at all -well. Further observation shows that they were really not -formed at all. For the animals did not, except 3 in K for a -certain period, do the several things in a constant order, nor -did they do them only once apiece. On the contrary, an -animal would pull the string several times after the bolt -had gone up with its customary click, and would do sometimes -one thing first, sometimes another. It may also be -noted here, in advance of its proper place, that these compound -associations are far below the simple in point of -permanence. The conduct of the animals is clearly not -that of minds having associated with a certain box’s interior -the idea of a succession of three movements. The animal -does not feel, “I did this and that and that and got out,” -or, more simply still, “this and that and that means getting -out.” If it did, we should soon see it doing what was -necessary without repetition and in a fairly constant time.</p> - -<p>I imagine, however, that an animal could learn to associate -with one sense-impression a compound act so as to -perform its elements in a regular order. By arranging -the box so that the second and third elements of the act -could be performed <i>only after the first had been</i>, and the -third <i>only after the first and second</i>, I am inclined to think<span class="pagenum"><a id="Page_135"></a>[135]</span> -you could get a very vigorous cat to learn the elements in -order and form the association perfectly. The case is -comparable to that of delicacy. The cat does not <i>tend</i> to -know what he is doing or to depart from the hit-or-miss -method of learning, but by associating the other combinations -of elements with failure to get pleasure, as in delicacy -experiments we associated the reactions to all but the one -signal, you could probably stamp out all but the 1, 2, 3 -order.</p> - -<p>The fact that you have to thus maneuver to get the -animals to have the three impulses in a regular order shows -that even when they are so, there is no idea of the three as -in an order, no thinking about them. Representations do -not get beyond their first intention. They are not carried -up into a free life which works them over anew. A complex -<i>act</i> does not imply a complex <i>thought</i>, or, more exactly, a -performance of a series does not imply the thought of a -series. Consequently, since the complexity of the act -depends on the power which failure has to stamp out all -other combinations, it is far more limited than in man.</p> - -<h3><span class="smcap">Number of Associations</span></h3> - -<p>The patent and important fact is that there are so few in -animals compared to the human stock. Even after taking -into account the various acts associated with various -smells, and exaggerating the possibility of getting an equipment -of associations in this field which man lacks, one must -recognize how far below man any animal is in respect to -mere quantity of associations. The associations with words -alone of an average American child of ten years far outnumber -those of any dog. A good billiard player probably -has more associations in connection with this single pastime<span class="pagenum"><a id="Page_136"></a>[136]</span> -than a dog with his whole life’s business. In the associations -which are homologous with those of animals man -outdoes them and adds an infinity of associations of a -different sort. The primates would seem, by virtue of their -incessant curiosity and addition to experience not for any -practical purpose but merely for love of mental life, to -represent an advanced stage toward this tremendous -quantity of associations. In man not only this activity -and curiosity, but also education, increases the number of -associations. Associations are formed more quickly, and -the absence of need for self-support during a long infancy -gives time. Associations thus formed work back upon -practical life, and by showing better ways decrease the -need of work, and so again increase the chance to form -associations. The result in the case of a human mind to-day -is the possession of a thesaurus of valuable associations, -if the time has been wisely spent. The free life of ideas, -imitation, all the methods of communication, and the -original accomplishments which we may include under the -head of invention, make the process of acquisition in many -cases quite a different one from the trial and error method -of the animals, and in general much shorten it.</p> - -<p>Small as it is, however, the number of associations which -an animal may acquire is probably much larger than popularly -supposed.</p> - -<p>My cats and dogs did not mix up their acts with the -wrong sense-impressions. The chicks that learned the -series of twenty-three associations did not find it a task -beyond their powers to retain them. Several three-day-old -chicks, which I caused to learn ten simple associations in -the same day, kept the things apart and on the next morning -went through each act at the proper stimulus. In the hands -of animal trainers some animals get a large number of<span class="pagenum"><a id="Page_137"></a>[137]</span> -associations perfectly in hand. The horse Mascot is claimed -to know the meaning of fifteen hundred signals! He -certainly knows a great many, and such as are naturally -difficult of acquisition. It would be an enlightening -investigation if some one could find out just how many -associations a cat or dog could form, if he were carefully -and constantly given an opportunity. The result would -probably show that the number was limited only by the -amount of motive available and the time taken to acquire -each. For there is probably nothing in their brain structure -which limits the number of connections that can be formed, -or would cause such connections, as they grew numerous, -to become confused.</p> - -<p>In their anxiety to credit animals with human powers, -the psychologists have disregarded or belittled, perhaps, -the possibilities of the strictly animal sort of association. -They would think it more wonderful that a horse should -respond differently to a lot of different numbers on the blackboard -than that he should infer a consequence from premises. -But if it be made a direct question of pleasure or -pain to an animal, he can associate any number of acts with -different stimuli. Only he does not form any associations -until he has to, until the direct benefit is apparent, and, for -his ordinary life, comparatively few are needed.</p> - -<p>On the whole our judgment from a comparison of man’s -associations with the brutes’ must be that a man’s are naturally -far more delicate, complex and numerous, and that -in as far as the animals attain delicacy, complexity, or a -great number of associations, they do it by methods which -man uses only in a very limited part of the field.</p> - -<p><span class="pagenum"><a id="Page_138"></a>[138]</span></p> - -<h3><span class="smcap">Permanence of Associations</span></h3> - -<p>Once formed, the connections by which, when an animal -feels a certain sense-impression, he does a certain thing, -persist over considerable intervals of time. With the curves -on <a href="#Page_39">pages 39 to 58</a> and <a href="#Page_60">60 to 65</a> are given in many instances<a id="FNanchor_17" href="#Footnote_17" class="fnanchor">[17]</a> -additional curves showing the animal’s proficiency after an -interval without experience. To these data may be added -the following:—</p> - -<p>The three chicks that had learned to escape through -the long labyrinth (involving twenty-three associations) -succeeded in repeating the performance after ten days’ -interval. Similarly the chicks used as imitators in V, W, X -and Y did not fail to perform the proper act after an interval -of twenty days. Cat 6, who had had about a hundred -experiences in C (button), had the association as perfect after -twenty days as when it left off. Cat 2, who had had 36 experiences -with C and had attained a constant time of 8 seconds, -escaped fourteen days later in 3, 9 and 8 seconds, respectively, -in three trials. Cat 1, after an interval of twenty -days, failed in 10 minutes to escape from C. The signal -for climbing up the front of the cage was reacted to by No. 3 -after an interval of twenty-four days. No. 10, who had -learned to discriminate between ‘I must feed those cats’ -and ‘I will not feed them,’ was tried after <i>eighty</i> days. It -was given 50 trials with the second signal mingled indiscriminately -with 25 trials with the first. I give the full record of -these, ‘yes’ equalling a trial in which she ‘forgot’ and -climbed up, ‘no’ equalling a trial in which she wisely stayed -down. Dashes represent intervening trials with the first<span class="pagenum"><a id="Page_139"></a>[139]</span> -signal, <i>to which she always reacted</i>. It will be observed -that 50 trials put the cat in the same position that 350 had -done in her first experience, although in that first experience -she had had only about a hundred trials after the association -had been perfected. The association between the first -signal and climbing up was perfect after the eighty days.</p> - -<h4><span class="smcap">Table 8</span></h4> - -<table class="borders"> - <tr> - <th><span class="smcap">Trials 1-7</span></th> - <th><span class="smcap">Trials 8-17</span></th> - <th><span class="smcap">Trials 18-27</span></th> - <th><span class="smcap">Trials 28-35</span></th> - <th><span class="smcap">Trials 36-42</span></th> - <th><span class="smcap">Trials 43-50</span></th> - </tr> - <tr> - <td class="tdc">—</td> - <td class="tdc">yes</td> - <td class="tdc">no</td> - <td class="tdc">—</td> - <td class="tdc">—</td> - <td class="tdc">—</td> - </tr> - <tr> - <td class="tdc">—</td> - <td class="tdc">yes</td> - <td class="tdc">yes</td> - <td class="tdc">—</td> - <td class="tdc">no</td> - <td class="tdc">—</td> - </tr> - <tr> - <td class="tdc">yes</td> - <td class="tdc">yes</td> - <td class="tdc">no</td> - <td class="tdc">—</td> - <td class="tdc">no</td> - <td class="tdc">—</td> - </tr> - <tr> - <td class="tdc">yes</td> - <td class="tdc">—</td> - <td class="tdc">no</td> - <td class="tdc">no</td> - <td class="tdc">—</td> - <td class="tdc">—</td> - </tr> - <tr> - <td class="tdc">no</td> - <td class="tdc">yes</td> - <td class="tdc">—</td> - <td class="tdc">no</td> - <td class="tdc">no</td> - <td class="tdc">—</td> - </tr> - <tr> - <td class="tdc">—</td> - <td class="tdc">yes</td> - <td class="tdc">—</td> - <td class="tdc">yes</td> - <td class="tdc">no</td> - <td class="tdc">no</td> - </tr> - <tr> - <td class="tdc">yes</td> - <td class="tdc">no</td> - <td class="tdc">yes</td> - <td class="tdc">no</td> - <td class="tdc">no</td> - <td class="tdc">no</td> - </tr> - <tr> - <td class="tdc">yes</td> - <td class="tdc">yes</td> - <td class="tdc">yes</td> - <td class="tdc">—</td> - <td class="tdc">—</td> - <td class="tdc">yes</td> - </tr> - <tr> - <td class="tdc">no</td> - <td class="tdc">no</td> - <td class="tdc">yes</td> - <td class="tdc">no</td> - <td class="tdc">—</td> - <td class="tdc">no</td> - </tr> - <tr> - <td class="tdc">no</td> - <td class="tdc">—</td> - <td class="tdc">yes</td> - <td class="tdc">yes</td> - <td class="tdc">no</td> - <td class="tdc">no</td> - </tr> - <tr> - <td class="tdc">—</td> - <td class="tdc">—</td> - <td class="tdc">no</td> - <td class="tdc">no</td> - <td class="tdc">no</td> - <td class="tdc">no</td> - </tr> - <tr> - <td class="tdc">—</td> - <td class="tdc">yes</td> - <td class="tdc">no</td> - <td class="tdc">no</td> - <td class="tdc"></td> - <td class="tdc">no</td> - </tr> - <tr> - <td class="tdc">—</td> - <td class="tdc">yes</td> - <td class="tdc"></td> - <td class="tdc"></td> - <td class="tdc"></td> - <td class="tdc">no</td> - </tr> - <tr> - <td class="tdc"></td> - <td class="tdc">—</td> - <td class="tdc"></td> - <td class="tdc"></td> - <td class="tdc"></td> - <td class="tdc"></td> - </tr> -</table> - -<p>All these data show that traces of the connections once -formed are very slow in being lost. If we allow that part -of the time in the first trial in all these cases is due to the -time taken to realize the situation (time not needed in the -trials when the association is forming and the animal is -constantly being dropped into boxes), we may say that the -association is as firm as ever for a considerable time after -practice at it is stopped. How long a time would be required -to annul the influence of any given quantity of -experience, say of an association which had been gone -through with ten times, I cannot say. It could, if profitable,<span class="pagenum"><a id="Page_140"></a>[140]</span> -easily be determined in any case. The only case of total -loss of the association (No. 1 in C) is so exceptional that I -fancy something other than lapse of time was its cause. -The main interest of these data, considered as quantitative -estimates, is not psychological, but biological. They show -what a tremendous advantage the well-developed association-process -is to an animal. The ways to different feeding -grounds, the actions of enemies, the appearance of noxious -foods, are all connected permanently with the proper reaction -by a few experiences which need be reënforced only -very rarely. Of course, associations without any permanence -would be useless, but the usefulness increases immensely -with such a degree of permanence as these results -witness. An interesting experiment from the biological -point of view would be to see how infrequently an experience -could occur and yet lead eventually to a perfect association. -An experiment approximating this is recorded in the time-curves -for Box H in <a href="#figure07">Figure 7, on page 47</a>. Three trials at a -time were given, the trials being two or three days apart. -As may be seen from the curves, the association was readily -formed.</p> - -<p>The chief psychological interest of these data is that they -show that permanence of associations <i>is not memory</i>. The -fact that a cat, when after an interval she is put into box G, -proceeds to immediately press the thumb piece and push -the door, does not at all mean that the cat feels the box -to be the same from which she weeks ago freed herself by -pushing down that thumb piece, or thinks about ever -having felt or done anything in that box. She does not -refer the present situation to a situation of the past and realize -that it is the same, but simply feels on being confronted -with that situation the same impulse which she felt before. -She does the thing now for just the same reason that she<span class="pagenum"><a id="Page_141"></a>[141]</span> -did it before, namely, because pleasure has connected that -act above all others with that sense-impression, so that it -is the one she feels like doing. Her condition is that of the -swimmer who starts his summer season after a winter’s -deprivation. When he jumps off the pier and hits the water, -he swims, not because he remembers that this is the way he -dealt with water last summer and so applies his remembrance -to present use, but just because experience has taught him -to feel like swimming when he hits the water. All talk -about recognition and memory in animals, if it asserts the -presence of anything more than this, is a gross mistake. -For real memory is an absolute thing, including everything -but forgetfulness. If the cat had real memory, it would, -when after an interval dropped into a box, remember that -from this box it escaped by doing this or that and consequently, -either immediately or after a time of recollection, -go do it, or else it would not remember and would fail -utterly to do it. On the contrary, we have all grades of -<i>partial</i> ‘forgetfulness,’ just like the grades of swimming one -might find if he dropped a dozen college professors into the -mill ponds of their boyhood, just like the grades of forgetfulness -of the associations once acquired on the ball field -which are manifested when on the Fourth of July the -‘solid men’ of a town get out to amuse their fellow citizens. -The animal makes attacks on a spot around the vital one, -or claws at the thing—but not so precisely as before, or -goes at it a while and then resorts to instinctive methods -of getting out. Its actions are exactly what would be -expected of an animal in whom the sense-impression aroused -the impulse imperfectly, or weakly, or intermittently, but -are not at all like the actions of one who felt, “I used to -get out of this box by pulling that loop down.” In fact, -the record of No. 10 given on <a href="#Page_139">page 139</a> seems to be final on<span class="pagenum"><a id="Page_142"></a>[142]</span> -this point. If at any time in the course of the 50 trials it -had <i>remembered</i> that ‘I will not feed them’ meant ‘no fish,’ -it would thenceforth have failed to react. It would have -stopped short in the ‘yes’ reactions, instead of gradually -decreasing their percentage. ‘Memory’ in animals, if one -still chooses to use the word, is <i>permanence of associations</i>, -not the presence of an idea of an experience attributed to -the past.</p> - -<p>To this proposition two corollaries may be added. First, -these phenomena of incomplete forgetfulness extend the -evidence that animals do not have a stock of independent -ideas, the return of which, plus past associates, equals -memory. Second, there is, properly speaking, no continuity -in their mental streams. The present thought does not -clutch the past to its bosom or hold the future in its womb. -The animal’s self is not a being ‘looking before and after,’ -but a direct practical association of feelings and impulses. -So far as experiences come continuously, they may be said -to form a continuous mental life, but there is no continuity -imposed from within. The feelings of its own body are -always present, and impressions from outside may come as -they come to us. When the habit of attending to the -elements of its associations and raising them up into the -life of free ideas is acquired, these permanent bodily associations -may become the basis of a feeling of self-hood and the -trains of ideas may be felt as a continuous life.</p> - -<h3><span class="smcap">Inhibition of Instincts by Habit</span></h3> - -<p>One very important result of association remains to be -considered, its inhibition of instincts and previous associations. -An animal who has become habituated to getting -out of a box by pulling a loop and opening the door will<span class="pagenum"><a id="Page_143"></a>[143]</span> -do so even though the hole in the top of the box be uncovered, -whereas, if, in early trials, you had left any such hole, -he would have taken the instinctive way and crawled -through it. Instances of this sort of thing are well-nigh -ubiquitous. It is a tremendous factor in animal life, -and the strongest instincts may thus be annulled. The -phenomenon has been already recognized in the literature -of the subject, a convenient account being found in James’ -‘Psychology,’ Vol. II, pages 394-397. In addition to such -accounts, one may note that the influence of association is -exerted in two ways. The instinct may wane by not being -used, because the animal forms the habit of meeting the -situation in a different way, or it may be actually inhibited. -An instance of the former sort is found in the history of -a cat which learns to pull a loop and so escape from a box -whose top is covered by a board nailed over it. If, after -enough trials, you remove a piece of the board covering -the box, the cat, when put in, will still pull the loop instead -of crawling out through the opening thus made. But, at -any time, if she happens to notice the hole, she <i>may</i> make -use of it. An instance of the second sort is that of a chick -which has been put on a box with a wire screen at its edge, -preventing her from jumping directly down, as she would -instinctively do, and forcing her to jump to another box on -one side of it and thence down. In the experiments which -I made, the chick was prevented by a second screen from -jumping directly from the second box also. That is, if in -the accompanying figure, A is a box 34 inches high, B a box -25 inches high, C a box 16 inches high, and D the pen with -the food and other chicks, the subject had to go A-B-C-D. -The chick tried at first to get through the screen, -pecked at it and ran up and down along it, looking at the -chicks below and seeking for a hole to get through. Finally<span class="pagenum"><a id="Page_144"></a>[144]</span> -it jumped to B and, after a similar process, to C. After -enough trials it forms the habit and when put on A goes -immediately to B, then -to C and down. Now -if, after 75 or 80 trials, -you take away the -screens, giving the chick -a free chance to go to D -from either A or B, and -then put it on A, the -following phenomenon -appears. The chick goes -up to the edge, looks over, walks up and down it for a while, -still looking down at the chicks below, and then goes and -jumps to B as habit has taught it to do. The same actions -take place on B. No matter how clearly the chick sees -the chance to jump to D, it does not do so. The impulse has -been truly inhibited. It is not the mere habit of going the -other way, but the impossibility of going <i>that</i> way. In one -case I observed a chick in whom the instinct was all but, yet -not quite, inhibited. When tried without the screen, it went -up to the edge to look over <i>nine times</i>, and at last, after -seven minutes, did jump straight down.</p> - -<div class="figcenter illowp100" id="figure23" style="max-width: 18.75em;"> - <img class="w100" src="images/figure23.jpg" alt=""> - <p class="caption"><span class="smcap">Fig. 23.</span></p> -</div> - -<h3><span class="smcap">Attention</span></h3> - -<p>I have presupposed throughout one function which it -will be well to now recognize explicitly, attention. As -usual, attention emphasizes and facilitates the process -which it accompanies. Unless the sense-impression is -focussed by attention, it will not be associated with the -act which comes later. Unless two differing boxes are attended -to, there will be no difference in the reactions to<span class="pagenum"><a id="Page_145"></a>[145]</span> -them. The really effective part of animal consciousness, -then, as of human, is the part which is attended to; attention -is the ruler of animal as well as human mind.</p> - -<p>But in giving attention its deserts we need not forget -that it is not here comparable to the whole of human attention. -Our attention to the other player and the ball -in a game of tennis <i>is</i> like the animal’s attention, but our -attention to a passage in Hegel, or the memory which -flits through our mind, or the song we hear, or the player -we idly watch, is <i>not</i>. There ought, I think, to be a separate -name for attention when working for immediate practical -associations. It is a different species from that which -holds objects so that we may define them, think about them, -remember them, etc., and the difference is, as our previous -sentence shows, not that between voluntary and involuntary -attention. The cat watching me for signs of my walking -to the cage with fish is not in the condition of the man -watching a ball game, but in that of the player watching -the ball speeding toward him. There is a notable difference -in the permanence of the impression. The man watching -the game can remember just how that fly was hit and how -the fielder ran for it, though he bestowed only a slight -quantity of attention on the matter, while the fielder may -attend to the utmost to the ball and yet not remember at -all how it came or how he ran for it. The one sort of attention -leads you to <i>think</i> about a thing, the other to <i>act</i> with -reference to it. We must be careful to remember that -when we say that the cat attended to what was said, we -do not mean that he thereby established an idea of it. -Animals are not proved to form separate ideas of sense-impressions -because they attend to them, for the kind of -attention they give is the kind which, when given by men, -results in practical associations, not in establishing ideas<span class="pagenum"><a id="Page_146"></a>[146]</span> -of objects. If attention rendered clear the idea, we should -not have the phenomena of incomplete forgetfulness lately -mentioned. The animal would get a definite idea of just -the exact thing done and would do it or nothing. The -human development of attention is in closest connection -with the acquisition of a stock of free ideas.</p> - -<h3><span class="smcap">Social Consciousness</span></h3> - -<p>Besides attention there is another topic somewhat apart -from our general one, which yet deserves a few words. It -concerns animals’ social consciousness, their consciousness -of the feelings of their fellows. Do animals, for example, -when they see others feeding, feel that the others are feeling -pleasure? Do they, when they fight, feel that the other -feels pain? So level-headed a thinker as Lloyd Morgan has -said that they do, but the conduct of my animals would -seem to show that they did not. For it has given us good -reason to suppose that they do not possess <i>any</i> stock of isolated -ideas, much less any abstracted, inferred, or transferred -ideas. These ideas of others’ feelings imply a power to transfer -states felt in oneself to another and realize them as there. -Now it seems that any ability to thus transfer and realize -an idea ought to carry with it an ability to form a transferred -association, to imitate. If the animal realizes the mental -states of the other animal who before his eyes pulls the -string, goes out through the door, and eats fish, he ought to -form the association, ‘impulse to pull string, pleasure of -eating fish.’ This we saw the animal could not do.</p> - -<p>In fact, pleasure in another, pain in another, is not a -sense-presentation or a representation or feeling of an object -of any sort, but rather a ‘meaning,’ a feeling ‘<i>of the -fact that</i>.’ It can exist only as something thought <i>about</i>.<span class="pagenum"><a id="Page_147"></a>[147]</span> -It is never ‘a bit of direct experience,’ but an abstraction -from our own life referred to that of another.</p> - -<p>I fancy that these feelings of others’ feelings may be connected -pretty closely with imitation, and for that reason -may begin to appear in the monkeys. There we have some -fair evidence for their presence in the tricks which monkeys -play on each other. Such feelings seem the natural explanation -of the apparently useless tail-pullings and such like -which make up the attractions of the monkey cage. These -may, however, be instinctive forms of play-activity or -merely examples of the general tendency of the monkeys -to fool with everything.</p> - -<h3><span class="smcap">Interaction</span></h3> - -<p>I hope it will not be thought impertinent if from the standpoint -of this research I add a word about a general psychological -problem, the problem of interaction. I have spoken -all along of the connection between the situation and a certain -impulse and act being stamped in when pleasure results -from the act and stamped out when it doesn’t. In this fact, -which is undeniable, lies a problem which Lloyd Morgan -has frequently emphasized. <i>How are pleasurable results able -to burn in and render predominant the association which led to -them?</i> This is perhaps the greatest problem of both human -and animal psychology. Unfortunately in human psychology -it has been all tangled up with the problems of free -will, mental activity, voluntary attention, the creation of -novel acts, and almost everything else. In our experiments -we get the data which give rise to the problem, in a very -elementary form.</p> - -<p>It should first be noted about the <i>fact</i> that the pleasure -does not burn in an impulse and act themselves, but an impulse<span class="pagenum"><a id="Page_148"></a>[148]</span> -and act <i>as connected with that particular situation</i>. No -cat ever goes around clawing, clawing, clawing all the time, -because clawing in these boxes has resulted in pleasure. -Secondly, the connection thus stamped in is <i>not contemporaneous, -but prior to</i> the pleasure. So much for the fact; -now for the explanation. I do not wish to rehearse or add -to the arguments with which so many pages have been already -filled by scientists and philosophers both. What we -need most is not argument, but accurate accounts of the -mental fact and of the brain-process. But I do wish to say -to the parallelist, what has not to my knowledge been said, -that if he presupposes, to account for this fact, a ‘physical -analogue of the hedonic consciousness,’ it is his bounden -duty to first show how any motion in any neurone or group -of neurones in the nervous system can possess this power of -stamping in any current which causes it. For no one would, -from our present knowledge of the brain, judge <i>a priori</i> that -any motion in any part of it could be conceived which should -be thus regnant over all the others. And next he must show -the possibility of the current which represents the association -being the excitant of the regnant motion in a manner -direct enough for the purpose.</p> - -<p>I wish also to say that whoever thinks that, going along -with the current which parallels the association, there is an -accompanying minor current, which parallels the pleasure -and which stamps in the first current when present with it, -flies directly in the face of the facts. <i>There is no pleasure -along with the association. The pleasure does not come until -after the association is done and gone.</i> It is caused by no -such minor current, but by the excitation of peripheral -sense-organs when freedom from confinement is realized or -food is secured. Of course, the notion of such a secondary -subcurrent is mythology, anyway.</p> - -<p><span class="pagenum"><a id="Page_149"></a>[149]</span></p> - -<p>To the interactionist I would say: “Do not any more -repeat in tiresome fashion that consciousness <i>does</i> alter -movement, but get to work and show when, where, in what -forms and to what degrees it does so. Then, even if it turns -out to have been a physical parallel that did the work, you -will, at least, have the credit of attaining the best knowledge -about the results and their conditions, even though you misnamed -the factor.”</p> - -<p>Besides this contribution to general psychology, I think -we may safely offer one to pedagogical science. At least -some of our results possess considerable pedagogical interest. -The fundamental form of intellection, the association-process -in animals, is one, we decided, which requires the -personal experience of the animal in all its elements. The -association cannot be taught by putting the animal through -it or giving it a chance to imitate. Now every observant -teacher realizes how often the cleverest explanation and the -best models for imitation fail. Yet often, in such cases, a -pupil, if somehow enticed to do the thing, even without -comprehension of what it means, even without any real -knowledge of what he is doing, will finally get hold of it. -So, also, in very many kinds of knowledge, the pupil who -does anything from imitation, or who does anything from -being put through it, fails to get a real and permanent mastery -of the thing. I am sure that with a certain type of -mind the only way to teach fractions in algebra, for example, -is to get the pupil to do, do, do. I am inclined to think that -in many individuals certain things cannot be learned save by -actual performance. And I think it is often a fair question, -when explanation, imitation and actual performance are all -possible methods, which is the best. We are here alongside -the foundations of mental life, and this hitherto unsuspected -law of animal mind may prevail in human mind to an extent<span class="pagenum"><a id="Page_150"></a>[150]</span> -hitherto unknown. The best way with children may often -be, in the pompous words of an animal trainer, ‘to arrange -everything in connection with the trick so that the animal -will be compelled by the laws of his own nature to perform -it.’</p> - -<p>This does not at all imply that I think, as a present school -of scientists seem to, that because a certain thing <i>has been</i> in -phylogeny we ought to repeat it in ontogeny. Heaven -knows that Dame Nature herself in ontogeny abbreviates -and skips and distorts the order of the appearance of organs -and functions, and for the best of reasons. We ought to -make an effort, as she does, to omit the useless and antiquated -and get to the best and most useful as soon as possible; -we ought to change what <i>is</i> to what <i>ought to be</i>, as far as we -can. And I would not advocate this animal-like method of -learning in place of the later ones unless it does the same -work better. I simply suggest that in many cases where -at present its use is never dreamed of, it may be a good -method. As the fundamental form of intellection, every -student of <i>theoretical</i> pedagogy ought to take it into account.</p> - -<p>There is one more contribution, this time to anthropology. -If the method of trial and error, with accidental success, be -the method of acquiring associations among the animals, the -slow progress of primitive man, the long time between stone -age and iron age, for instance, becomes suggestive. Primitive -man probably acquired knowledge by just this process, -aided possibly by imitation. At any rate, progress was not -by seeing through things, but by accidentally hitting upon -them. Very possibly an investigation of the history of -primitive man and of the present life of savages in the light -of the results of this research might bring out old facts in a -new and profitable way.</p> - -<p>Comparative psychology has, in the light of this research,<span class="pagenum"><a id="Page_151"></a>[151]</span> -two tasks of prime importance. One is to study the passage -of the child mind from a life of immediately practical associations -to the life of free ideas; the other is to find out how far -the anthropoid primates advance toward a similar passage, -and to ascertain accurately what faint beginnings or preparations -for such an advance the early mammalian stock may -be supposed to have had. In this latter connection I think -it will be of the utmost importance to bear in mind the possibility -that <i>the present anthropoid primates may be mentally -degenerate</i>. Their present aimless activity and incessant, -but largely useless, curiosity may be the degenerated -vestiges of such a well-directed activity and useful curiosity -as led <i>homo sapiens</i> to important practical discoveries, -such as the use of tools, the art of making fire, etc. It is -even a remote possibility that their chattering is a <i>relic</i> -of something like language, not a <i>beginning</i> of such. Comparative -psychology should use the phenomena of the -monkey mind of to-day to find out what the primitive mind -from which man’s sprung off was like. That is the important -thing to get at, and the question whether the present -monkey mind has not gone back instead of ahead is an all-important -question. A natural and perhaps sufficient cause -of degeneracy would be arboreal habits. The animal that -found a means of survival in his muscles might well lose the -means before furnished by his brain.</p> - -<p>To these disconnected remarks still another must be added, -addressed this time to the anecdote school. Some member -of it who has chanced to read this may feel like saying: -“This experimental work is all very well. Your cats and -dogs represent, it is true, specimens from the top stratum -of animal intelligence, and your negations, based on their -conduct, may be authoritative so far as concerns the -average, typical mammalian mind. But our anecdotes<span class="pagenum"><a id="Page_152"></a>[152]</span> -do not claim to be stories of the conduct of the average -or type, but of those exceptional individuals who have -begun to attain higher powers. And, if even a few -dogs and cats have these higher powers, our contention -is, in a modified form, upheld.” To all this I agree, -provided the anecdote school now realize just what -sort of a position they hold. They are clearly in pretty -much the same position as spiritualists. Their anecdotes -are on pretty much the same level as the anecdotes of -thought-transference, materializations of spirits, supernormal -knowledge, etc. Not in quite the same position, for -far greater care has been given by the Psychical Research -Society to establishing the criteria of authenticity, to insuring -good observation, to explaining by normal psychology -all that can be so explained, in the case of the latter than -the anecdote school has done in the case of the former. The -off-hand explanation of certain anecdotes by invoking reason, -or imitation, or recognition, or feelings of qualities, is -on a par with the explanation of trance-phenomena and such -like by invoking the spirits of dead people. I do not deny -that we may get lawfully a supernormal psychology, or -that the supernormal acts it finds may turn out to be explained -by these functions which I have denied to the normal -animal mind. But I must soberly declare that I think -there is less likelihood that such functions are the explanation -of animal acts than that the existence of the spirits of -dead people is the true explanation of the automatisms of -spiritualistic phenomena. So much for the anecdote school, -if it calls itself by its right name and pretends only to give -an <i>abnormal</i> animal psychology. The sad fact has been that -it has always pushed forward these exceptions as the essential -phenomena of animal mind. It has built up a general -psychology from abnormal data. It is like an anatomy -written from observations on dime-museum freaks.</p> - -<p><span class="pagenum"><a id="Page_153"></a>[153]</span></p> - -<h3><span class="smcap">Conclusion</span></h3> - -<p>I do not think it is advisable here, at the close of this -paper, to give a summary of its results. The paper itself -is really only such a summary with the most important evidence, -for the extent of territory covered and the need of -brevity have prevented completeness in explanation or illustration. -If the reader cares here, at the end, to have the -broadest possible statement of our conclusions and will take -the pains to supply the right meaning, we might say that -our work has described a method, crude but promising, and -has made the beginning of an exact estimate of just what -associations, simple and compound, an animal can form, -how quickly he forms them, and how long he retains them. -It has described the method of formation, and, on the condition -that our subjects were representative, has rejected -reason, comparison or inference, perception of similarity, -and imitation. It has denied the existence in animal consciousness -of any important stock of free ideas or impulses, -and so has denied that animal association is homologous -with the association of human psychology. It has homologized -it with a certain limited form of human association. It -has proposed, as necessary steps in the evolution of human -faculty, a vast increase in the number of associations, signs -of which appear in the primates, and a freeing of the elements -thereof into independent existence. It has given us -an increased insight into various mental processes. It has -convinced the writer, if not the reader, that the old speculations -about what an animal could do, what it thought, -and how what it thought grew into what human beings -think, were a long way from the truth, and <i>not on the road -to it</i>.</p> - -<p>Finally, I wish to say that, although the changes proposed<span class="pagenum"><a id="Page_154"></a>[154]</span> -in the conception of mental development have been suggested -somewhat fragmentarily and in various connections, -that has not been done because I think them unimportant. -On the contrary, I think them of the utmost importance. I -believe that our best service has been to show that animal -intellection is made up of a lot of specific connections, whose -elements are restricted to them, and which subserve practical -ends <i>directly</i>, and to homologize it with the intellection -involved in such human associations as regulate the conduct -of a man playing tennis. The fundamental phenomenon -which I find presented in animal consciousness is one which -can harden into inherited connections and reflexes, on the -one hand, and thus connect naturally with a host of the -phenomena of animal life; on the other hand, it emphasizes -the fact that our mental life has grown up as a mediation between -stimulus and reaction. The old view of human consciousness -is that it is built up out of elementary sensations, -that very minute bits of consciousness come first and gradually -get built up into the complex web. It looks for the -beginnings of consciousness to <i>little</i> feelings. This our view -abolishes and declares that the progress is not from little and -simple to big and complicated, but from direct connections to -indirect connections in which a stock of isolated elements plays -a part, is from ‘pure experience’ or undifferentiated feelings, -to discrimination, on the one hand, to generalizations, abstractions, -on the other. If, as seems probable, the primates -display a vast increase of associations, and a stock of free-swimming -ideas, our view gives to the line of descent a meaning -which it never could have so long as the question was -the vague one of more or less ‘intelligence.’ It will, I hope, -when supported by an investigation of the mental life of -the primates and of the period in child life when these directly -practical associations become overgrown by a rapid<span class="pagenum"><a id="Page_155"></a>[155]</span> -luxuriance of free ideas, show us the real history of the -origin of human faculty. It turns out apparently that -a modest study of the facts of association in animals -has given us a working hypothesis for a comparative -psychology.</p> - -<hr class="chap x-ebookmaker-drop"> - -<div class="chapter"> - -<p><span class="pagenum"><a id="Page_156"></a>[156]</span></p> - -<h2 class="nobreak" id="CHAPTER_III">CHAPTER III<br> -<span class="smcap">The Instinctive Reactions of Young Chicks</span><a id="FNanchor_18" href="#Footnote_18" class="fnanchor">[18]</a></h2> - -</div> - -<p>The data to be presented in this article were obtained in -the course of a series of experiments conducted in connection -with the psychological laboratory of Harvard University -during the year 1896-1897. About sixty chicks were -used as subjects. In general their experiences were entirely -under my control from birth. Where this was not true, the -conditions of their life previous to the experiments were -known, and were such as would have had no influence in -determining the quality of their reactions in the particular -experiments to which they were subjected. It is not worth -while to recount the means taken so to regulate the chick’s -environment that his experience along certain lines should -be in its entirety known to the observer and that consequently -his inherited abilities could be surely differentiated. -The nature of the experiments will, in most cases, be such -that little suspicion of the influence of education by experience -will be possible. In the other cases I will mention -the particular means then taken to prevent such influence.</p> - -<p>Some of my first experiments were on color vision in -chicks from 18 to 30 hours old, just old enough to move -about readily and to be hungry. On backgrounds of white -and black cardboard were pasted pieces of colored paper -about 2 mm. square. On each background there were six<span class="pagenum"><a id="Page_157"></a>[157]</span> -of these pieces,—one each of yellow, red, orange, green, -blue and black (on the white ground) or white (on the black). -They were in a row about half an inch apart. The chicks -had been in darkness for all but three or four hours of their -life so far. During those few hours the incubator had been -illuminated and the chicks had that much chance to learn -color.</p> - -<p>The eight chicks were put, one at a time, on the sheet of -cardboard facing the colored spots. Count was kept of the -number of times that they pecked at each spot and, of -course, they were watched to see whether they would peck -at all at random. In the experiments with the white background -all the colors were reacted to (<i>i.e.</i> pecked at) except -black (but the letters on a newspaper were pecked at by -the same chicks the same day). One of the chicks pecked -at all five, one at four, three at three, one at two and one at -yellow only. These differences are due probably to accidental -position or movements. Taking the sums of the reactions -to each color-spot we get the following table:—</p> - -<h3>I</h3> - -<table class="borders"> - <tr> - <th></th> - <th><span class="smcap">Times<br>Reacted to</span></th> - <th><span class="smcap">Total Number<br>of Pecks</span><a id="FNanchor_19" href="#Footnote_19" class="fnanchor">[19]</a></th> - </tr> - <tr> - <td>Red</td> - <td class="tdr">12</td> - <td class="tdr">31</td> - </tr> - <tr> - <td>Yellow</td> - <td class="tdr">9</td> - <td class="tdr">21</td> - </tr> - <tr> - <td>Orange</td> - <td class="tdr">6</td> - <td class="tdr">34</td> - </tr> - <tr> - <td>Green</td> - <td class="tdr">5</td> - <td class="tdr">11</td> - </tr> - <tr> - <td>Blue</td> - <td class="tdr">1</td> - <td class="tdr">3</td> - </tr> -</table> - -<p>I should attach no importance whatever to the quantitative -estimate given in the table. The only fact of value so<span class="pagenum"><a id="Page_158"></a>[158]</span> -far is the evidence that from the first the chick reacts to all -colors. In no case was there any random pecking at the -white surface of the cardboard.</p> - -<p>On a black background the same chicks reacted to all the -colors.</p> - -<p>II is a table of the results.</p> - -<h3>II</h3> - -<table class="borders"> - <tr> - <th></th> - <th><span class="smcap">Times<br>Reacted to</span></th> - <th><span class="smcap">Total Number<br>of Pecks</span></th> - </tr> - <tr> - <td>White</td> - <td class="tdr">6</td> - <td class="tdr">19</td> - </tr> - <tr> - <td>Blue</td> - <td class="tdr">4</td> - <td class="tdr">11</td> - </tr> - <tr> - <td>Red</td> - <td class="tdr">4</td> - <td class="tdr">8</td> - </tr> - <tr> - <td>Green</td> - <td class="tdr">4</td> - <td class="tdr">4</td> - </tr> - <tr> - <td>Orange</td> - <td class="tdr">2</td> - <td class="tdr">7</td> - </tr> - <tr> - <td>Yellow</td> - <td class="tdr">2</td> - <td class="tdr">4</td> - </tr> -</table> - -<p>In other experiments chicks were tried with green spots on -a red ground, red spots on a green ground, yellow spots on an -orange ground, green spots on a blue ground, and black spots -on a white ground. All were reacted to. Thus, what is apparently -a long and arduous task to the child is heredity’s -gift to the chick. It is conceivable, though to me incredible, -that what the chick reacts to is not the color, but the -very minute elevation of the spot. My spots were made so -that they were only the thickness of thin paper above pasteboard. -Any one who cares to resort to the theory that this -elevation caused the reaction can settle the case by using -color-spots absolutely level with the surface.<a id="FNanchor_20" href="#Footnote_20" class="fnanchor">[20]</a></p> - -<p><span class="pagenum"><a id="Page_159"></a>[159]</span></p> - -<h3><span class="smcap">Instinctive Reactions to Distance, Direction, Size, etc.</span></h3> - -<p>I have purposely chosen this awkward heading rather -than the simple one, Space-Perception, because I do not wish -to imply that there is in the young chick such consciousness -of space-facts as there is in human beings. All that will be -shown here is that he reacts appropriately in the presence of -space-facts, reacts in a fashion which would in the case of a -man go with genuine perception of space.</p> - -<p>If one puts a chick on top of a box in sight of his fellows -below, the chick will regulate his conduct by the height of -the box. To be definite, we may take the average chick of -about 95 hours. If the height is less than 10 inches, he will -jump down as soon as you put him up. At 16 inches he will -jump in from 5 seconds to 3 or 4 minutes. At 22 inches he -will still jump down, but after more hesitation. At 27½ -inches 6 chicks out of eight at this age jumped within 5 minutes. -At 39 inches the chick <i>will <span class="smcap">not</span> jump down</i>. The -numerical values given here would, of course, vary with the -health, development, hunger and degree of lonesomeness of -the chick. All that they are supposed to show is that at any -given age the chick without experience of heights regulates -his conduct rather accurately in accord with the space-fact -of distance which confronts him. The chick does not peck -at objects remote from him, does not, for instance, confuse -a bird a score of feet away with a fly near by, or try to get -the moon inside his bill. Moreover, he reacts in pecking -with considerable accuracy at the very start. Lloyd Morgan -has noted that in his very first efforts the chick often -fails to seize the object, though he hits it, and on this ground -has denied the perfection of the instinct. But, as a matter -of fact, the pecking reaction may be as perfect at birth as it is<span class="pagenum"><a id="Page_160"></a>[160]</span> -after 10 or 12 days’ experience. It certainly is not perfect -then. I took nine chicks from 10 to 14 days old and placed -them one at a time on a clear surface over which were scattered -grains of cracked wheat (the food they had been eating -in this same way for a week) and watched the accuracy -of their pecking. Out of 214 objects pecked at, 159 were -seized, 55 <i>were not</i>. Out of the 159 that were seized, <i>only</i> -116 were seized on the first peck, 25 on the second, 16 on the -third, and the remaining two on the fourth. Of the 55 that -were not successfully seized, 31 were pecked at only once, -10 twice, 10 three times, 3 four times and 1 five times. I -fancy one would find that adult fowls would show by no -means a perfect record. So long as chicks with ten days’ -experience fail to seize on the first trial 45 per cent of the -time, it is hardly fair to argue against the perfection of the -instinct on the ground of failures to seize during the first day.</p> - -<p>The chick’s practical appreciation of space-facts is seen -further in his attempts to escape when confined. Put chicks -only twenty or thirty hours old in a box with walls three or -four inches high and they will react to the perpendicularity -of the confining walls by trying to jump over them. In fact, -in the ways he moves, the directions he takes and the objects -he reacts to, the chicken has prior to experience the power -of appropriate reaction to colors and facts of all three dimensions.</p> - -<h3><span class="smcap">Instinctive Muscular Coördinations</span></h3> - -<p>In the acts already described we see fitting coördinations -at work in the chick’s reactions to space-facts. A few more -samples may be given. In jumping down from heights the -chick does not walk off or fall off (save rarely), but jumps -off. He meets the situation “loneliness on a small eminence” -by walking around the edge and peering down; he meets the<span class="pagenum"><a id="Page_161"></a>[161]</span> -situation “sight of fellow chicks below” by (after an amount -of hesitation varying roughly with the height) jumping off, -holding his stubby wings out and keeping right side up. He -lands on his feet almost every time and generally very -cleverly. A four days’ chick will jump down a distance -eight times his own height without hurting himself a bit. If -one takes a chick two or three weeks old who has never had -a chance to jump up or down, and puts him in a box with -walls three times the height of the chick’s back, he will -find that the chick will jump, or rather fly, nearly, if not -quite, over the wall, flapping his wings lustily and holding -on to the edge with his neck while he clambers over. Chicks -one day old will, in about 57 per cent of the cases, balance -themselves for five or six seconds when placed on a stiff -perch. If eight or nine days old, they will, though never -before on any perch or anything like one, balance perfectly -for a minute or more. The muscular coördination required -is invoked immediately when the chick feels the situation -“feet on a perch.” The <i>strength</i> is lacking in the first few -days. From the fifth or sixth day on chicks are also able -(their ability increases with age) to balance themselves on a -slowly swinging perch.</p> - -<p>Another complex coördination is seen in the somewhat remarkable -instinct of swimming. Chicks only a day or two -old will, if tossed into a pond, head straight for the shore and -swim rapidly to it. It is impossible to compare their movements -in so doing with those of ducklings, for the chick is -agitated, paddles his feet very fast and swims to get out, -not for swimming’s sake. Dr. Bashford Dean, of Columbia -University, has suggested to me that the movements -may not be those of swimming, but only of running. At all -events, they are utterly different from those of an adult fowl. -In the case of the adult there is no vigorous instinct to strike<span class="pagenum"><a id="Page_162"></a>[162]</span> -out toward the shore. The hen may try to fly back into the -boat if it is dropped overboard, and whether dropped in or -slung in from the shore, will float about aimlessly for a while -and only very slowly reach the shore. The movements the -chick makes do look to be such as trying to run in water -might lead to, but it is hard to see why a hen shouldn’t run -to get out of cold water as well as a chick. If, on the other -hand, the actions of the chick are due to a real swimming instinct, -it is easy to see that, being unused, the instinct might -wane as the animal grew up.</p> - -<p>Such instinctive coördinations as these, together with the -walking, running, preening of feathers, stretching out of leg -backward, scratching the head, etc., noted by other observers, -make the infant chick a very interesting contrast to the -infant man. That the helplessness of the child is a sacrifice -to plasticity, instability and consequent power to develop we -all know; but one begins to realize how much of a sacrifice -when one sees what twenty-one days of embryonic life do for -the chick brain. And one cannot help wondering whether -some of the space-perception we trace to experience, some -of the coördinations which we attribute to a gradual development -from random, accidentally caused movements may -not be more or less definitely provided for by the child’s -inherited brain structure. Walking has been found to be -instinctive; why not other things?</p> - -<h3><span class="smcap">Instinctive Emotional Reactions</span></h3> - -<p>The only experiments to which I wish to refer at length -under this heading are some concerning the chick’s instinctive -fears. Before describing them, it may be well to mention -their general bearing on the results obtained by Spalding -and Morgan. They corroborate Morgan’s decision that -no well-defined specific fears are present; that the fears of<span class="pagenum"><a id="Page_163"></a>[163]</span> -young chicks are of strange moving objects in general, shock -in general, strange sounds in general. On the other hand, no -such general disturbances of the chick’s environment led to -such well-marked reactions as Spalding described. And so -when Morgan thinks that such behavior as Spalding witnessed -on the part of the chick that heard the hawk’s cry -demands for its explanation nothing more than a general -fear of strange sounds, my experiments do not allow me to -agree with him. If Spalding really saw the conduct which -he says the chick exhibited on the third day of its life in the -presence of man, and later at the stimulus of the sight or -sound of the hawk, there are specific reactions. For the -running, crouching, silence, quivering, etc., that one gets -by yelling, banging doors, tormenting a violin, throwing -hats, bottles, or brushes at the chick is never anything like so -pronounced and never lasts one tenth as long as it did with -Spalding’s chicks. But, as to the fear of man, Spalding -must have been deluded. In the second, third and fourth -days there is no such reaction to the sight of man as he -thought he saw. Miss Hattie E. Hunt, in the <i>American -Journal of Psychology</i>, Vol. IX., No. 1, asserts that there is -no instinctive fear of a cat. Morgan did not find such. I -myself put chicks of 2, 5, 9 and 17 days (different individuals -each time, 11 in all) in the presence of a cat. They -showed no fear, but went on eating as if there was nothing -about. The cat was still, or only slowly moving. I further -put a young kitten (eight inches long) in the pen with -chicks. He felt of them with his paw, and walked around -among them for five or ten minutes, yet they showed no fear -(nor did he instinctively attack them). If, however, you let -a cat jump at chicks in real earnest, they will not stay to be -eaten, but will manifest fear—at least chicks three to four -weeks old will. I did not try this experiment with chicks<span class="pagenum"><a id="Page_164"></a>[164]</span> -at different ages, because it seemed rather cruel and degrading -to the experimenter. When in the case of the older chicks -nature happened to make the experiment, it was hard to decide -whether there was more violent fear of the jumping cat -than there was when one threw a basket or football into the -pen. There was not very much more.</p> - -<p>We may now proceed to a brief recital of the facts shown -by the experiments in so far as they are novel. It should be -remembered throughout that in every case chicks of different -ages were tested so as to demonstrate transitory instincts -if such existed, <i>e.g.</i>, the presence of a fear of flame -was tested with chicks 59 and 60, one day old, 30 and 32, two -days old, 21 and 22, three days old, 23 and 24, seven days -old, 27 and 29, nine days old, 16 and 19, eleven days old, -and so on up to twenty-days-old chicks. By thus using -different subjects at each trial one, of course, eliminates any -influence of experience.</p> - -<p>The first notable fact is that there develops in the first -month a general fear of novel objects in motion. For four -or five days there seems to be no such. You may throw a -hat or slipper or shaving mug at a chick of that age, and he -will do no more than get out of the way of it. But a twenty-five-days-old -chick will generally chirr, run and crouch for -five or ten seconds. My records show this sort of thing beginning -about the tenth day, but it is about ten days more -before it is very marked. In general, also, the reaction is -more pronounced if many chicks are together, and is then -displayed earlier (only two at a time were taken in the experiments -the results of which have just been quoted). -Thus the reaction is to some degree a social performance, the -presence of other chicks combining with the strange object -to increase the vigor of the reaction. Chicks ordinarily -scatter apart when they thus run from an object.</p> - -<p><span class="pagenum"><a id="Page_165"></a>[165]</span></p> - -<p>One witnesses a similar gradual growth of the fear of man -(not as such probably, but merely as a large moving object). -For four or five days you can jump at the chick, grab at it -with your hands, etc., without disturbing it in the least. A -chick twenty days old, however, although he has never been -touched or approached by a man, and in some cases never -seen one except as the daily bringer of food, and has never -been in any way injured by any large moving object of any -sort, will run from you if you try to catch him or even get -very near him. There is, however, even then, nothing like -the utter fear described by Spalding.</p> - -<p>Up to thirty days there was no fear of a mocking bird into -whose cage the chicks were put, no fear of a stuffed hawk or a -stuffed owl (kept stationary). Chicks try to escape from -water (even though warmed to the temperature of their -bodies) from the very first. Up to forty days there appears -no marked waning of the instinct. They did not show any -emotional reaction to the flame produced by six candles -stuck closely together. From the start they react instinctively -to confinement, to loneliness, to bodily restraint, but -their feeling in these cases would better be called discomfort -than fear. From the 10th or 12th to the 20th day, and -probably later and very possibly earlier, one notices in -chicks a general avoidance of open places. Turn them out -in your study and they will not go out into the middle of the -room, but will cling to the edges, go under chairs, around -table legs and along the walls. One sees nothing of the sort -up through the fourth day. Some experiments with feeding -hive bees to the chicks are interesting in connection with -the following statement by Lloyd Morgan: “One of my -chicks, three or four days old, snapped up a hive bee and -ran off with it. Then he dropped it, shook his head much -and often, and wiped his bill repeatedly. I do not think<span class="pagenum"><a id="Page_166"></a>[166]</span> -he had been stung: <i>probably he tasted the poison</i>” (‘Introduction -to Comparative Psychology,’ p. 86). I fed seven -bees apiece to three chicks from ten to twenty days old. -<i>They ate them all greedily</i>, first smashing them down on the -ground violently in a rather dexterous manner. Apparently -this method of treatment is peculiar to the object. Chicks -<i>three</i> days old did not eat the bees. Some pecked at -them, but none would snap them up, and when the bee -approached, they sometimes sounded the danger note.</p> - -<p>Finally an account may be given of the reaction of chicks -at different ages, up to twenty-six days, to loud sounds. -These were the sounds made by clapping the hands, slamming -a door, whistling sharply, banging a tin pan on the -floor, mewing like a cat, playing a violin, thumping a coal -scuttle with a shovel, etc. Two chicks were together in -each experiment. Three fourths of the times no effect -was produced. On the other occasions there was some running -or crouching or, at least, starting to run or crouch; -but, as was said, nothing like what Spalding reports as the -reaction to the ‘cheep’ of the hawk. It is interesting to -notice that the two most emphatic reactions were to the -imitation mew. One time a chick ran wildly, chirring, and -then crouched and stayed still until I had counted 105. The -other time a chick crouched and stayed still until I counted -40. But the other chick with them did not; and in a dozen -other cases the ‘meaw’ had no effect.</p> - -<p>I think that the main interest of most of these experiments -is the proof they afford that instinctive reactions are not -necessarily definite, perfectly appropriate and unvarying responses -to accurately sensed and, so to speak, estimated -stimuli. The old notion that instinct was a God-given substitute -for reason left us an unhappy legacy in the shape -of the tendency to think of all inherited powers of reaction as<span class="pagenum"><a id="Page_167"></a>[167]</span> -definite particular acts invariably done in the presence of -certain equally definite situations. Such an act as the -spider’s web-spinning might be a stock example. Of -course, there are many such instinctive reactions in which a -well-defined act follows a well-defined stimulus with the -regularity and precision with which the needle approaches -the magnet. But our experiments show that there are acts -just as truly instinctive, depending in just the same way on -inherited brain-structure, but characterized by being vague, -irregular, and to some extent dissimilar, reactions to vague, -complex situations.</p> - -<p>The same stimulus doesn’t always produce just the same -effect, doesn’t produce precisely the same effect in all individuals. -The chick’s brain is evidently prepared in a -general way to react more or less appropriately to certain -stimuli, and these reactions are among the most important -of its instincts or inherited functions. But yet one cannot -take these and find them always and everywhere. This -helps us further to realize the danger of supposing that in -observation of animals you can depend on a rigid uniformity. -One would never suppose because one boy twirled -his thumb when asked a question that all boys of that age -did. But naturalists have been ready to believe that -because one young animal made a certain response to a certain -stimulus, the thing was an instinct common to all in precisely -that same form. But a loud sound may make one -chick run, another crouch, another give the danger call, and -another do nothing whatever.</p> - -<p>In closing this article I may speak of one instinct which -shows itself clearly from at least as early as the sixth day, -which is preparatory to the duties of adult life and of no -other use whatsoever. It is interesting in connection with -the general matter of animal play. The phenomenon is as<span class="pagenum"><a id="Page_168"></a>[168]</span> -follows: The chicks are feeding quietly when suddenly two -chicks rush at each other, face each other a moment and then -go about their business. This thing keeps up and grows -into the ordinary combat of roosters. It is rather a puzzle -on any theory that an instinct needed so late should begin -to develop so early.</p> - -<hr class="chap x-ebookmaker-drop"> - -<div class="chapter"> - -<p><span class="pagenum"><a id="Page_169"></a>[169]</span></p> - -<h2 class="nobreak" id="CHAPTER_IV">CHAPTER IV<br> -<span class="smcap">A Note on the Psychology of Fishes</span><a id="FNanchor_21" href="#Footnote_21" class="fnanchor">[21]</a></h2> - -</div> - -<p>Numerous facts witness in a vague way to the ability of -fishes to profit by experience and fit their behavior to situations -unprovided for by their innate nervous equipment. -All the phenomena shown by fishes as a result of taming are, -of course, of this sort. But such facts have not been exact -enough to make clear the mental or nervous processes involved -in such behavior, or simple enough to be available as -demonstrations of such processes. It seemed desirable to -obtain evidence which should demonstrate both the fact and -the process of learning or intelligent activity in the case of -fishes and demonstrate them so readily that any student -could possess the evidence first hand.</p> - -<p>Through the kindness of the officials of the United States -Fish Commission at Woods Holl, especially of the director, -Dr. Bumpus, I was able to test the efficiency of some simple -experiments directed toward this end. The common Fundulus -was chosen as a convenient subject, and also because -of the neurological interest attaching to the formation of -intelligent habits by a vertebrate whose forebrain lacks a -cortex.</p> - -<p>The fishes studied were kept in an aquarium (about 4 feet -long by 2 feet wide, with a water depth of about 9 inches) -represented by <a href="#figure24">Fig. 24</a>. The space at one end, as represented<span class="pagenum"><a id="Page_170"></a>[170]</span> -by the lines in the figure, was shaded from the sun by -a cover, and all food was dropped in at this end. Along each -side of the aquarium were -fastened simple pairs of -cleats, allowing the experimenter -to put across -it partitions of wood, -glass or wire screening. -One of these in position -is shown in the figure by -the dotted line. These partitions were made each with an -opening, as shown in <a href="#figure25">Fig. 25</a>. If now we cause the fish to -leave his shady corner and swim up to -the sunny end by putting a slide (without -any opening) in behind him at <i>D</i> -and moving it gently from <i>D</i> to <i>A</i> and -then place, say slide <i>I</i>, across the -aquarium at 1, we shall have a chance -to observe the animal’s behavior to -good purpose.</p> - -<div class="figcenter illowp100" id="figure24" style="max-width: 18.75em;"> - <img class="w100" src="images/figure24.jpg" alt=""> - <p class="caption"><span class="smcap">Fig. 24.</span></p> -</div> - -<div class="figcenter illowp50" id="figure25" style="max-width: 12.5em;"> - <img class="w100" src="images/figure25.jpg" alt=""> - <p class="caption"><span class="smcap">Fig. 25.</span></p> -</div> - -<p>This fish dislikes the sunlight and -tries to get back to <i>D</i>. He reacts to -the situation in which he finds himself -by swimming against the screen, bumping against it here -and there along the bottom. He may stop and remain -still for a while. He will occasionally rise up toward the -top of the water, especially while swimming up and down -the length of the screen. When he happens to rise up to the -top at the right-hand end, he has a clear path in front of him -and swims to <i>D</i> and feels more comfortable.</p> - -<p>If, after he has enjoyed the shade fifteen minutes or more, -you again confine him in <i>A</i>, and keep on doing so six or eight -times a day for a day or so, you will find that he swims<span class="pagenum"><a id="Page_171"></a>[171]</span> -against the screen less and less, swims up and down along it -fewer and fewer times, stays still less and less, until finally -his only act is to go to the right-hand side, rise up, and -swim out. In correspondence with this change in behavior -you will find a very marked decrease in the time he takes to -escape. The fish has clearly profited by his experience and -modified his conduct to suit a situation for which his innate -nervous equipment did not definitely provide. He has, in -common language, <i>learned</i> to get out.</p> - -<p>This particular experiment was repeated with a number of -individuals. Another experiment was made, using three -slides, <i>II</i>, <i>III</i>, and another, requiring the fish to find his way -from <i>A</i> to <i>B</i>, <i>B</i> to <i>C</i>, and from <i>C</i> to <i>D</i>. The results of these -and still others show exactly the same general mental -process as does the one described—a process which I have -discussed at length elsewhere.</p> - -<p>Whatever interest there is in the demonstration in the case -of the bony fishes of the same process which accounts for so -much of the behavior of the higher vertebrates may be left to -the neurologists. The value of the experiment, if any, to -most students will perhaps be the extreme simplicity of the -method, the ease of administering it, and its possibilities. -By using long aquaria, one can study the formation of very -complex series of acts and see to what extent any fish can -carry the formation of such series. By proper arrangements -the delicacy of discrimination of the fish in any respect -may be tested. The artificiality of the surroundings -may, of course, be avoided when desirable.</p> - -<hr class="chap x-ebookmaker-drop"> - -<div class="chapter"> - -<p><span class="pagenum"><a id="Page_172"></a>[172]</span></p> - -<h2 class="nobreak" id="CHAPTER_V">CHAPTER V<br> -<span class="smcap">The Mental Life of the Monkeys; an Experimental Study</span><a id="FNanchor_22" href="#Footnote_22" class="fnanchor">[22]</a></h2> - -</div> - -<p>The literary form of this monograph is not at all satisfactory -to its author. Compelled by practical considerations -to present the facts in a limited space, he has found it -necessary to omit explanation, illustration and many rhetorical -aids to clearness and emphasis. For the same reason -detailed accounts of the administration of the experiments -have not always been given. In many places theoretical -matters are discussed with a curtness that savors of dogmatism. -In general when a theoretical point has appeared -justified by the evidence given, I have, to economize space, -withheld further evidence.</p> - -<p>There is, however, to some extent a real fitness in the lack -of clearness, completeness and finish in the monograph. For -the behavior of the monkeys, by virtue of their inconstant -attention, decided variability of performance, and generally -aimless, unforetellable conduct would be falsely represented -in any clean-cut, unambiguous, emphatic exposition. The -most striking testimony to the mental advance of the monkeys -over the dogs and cats is given by the difficulty of making -clear emphatic statements about them.</p> - -<p><span class="pagenum"><a id="Page_173"></a>[173]</span></p> - -<h3><span class="smcap">Introduction</span></h3> - -<p>The work to be described in this paper is a direct continuation -of the work done by the author in 1897-1898 and -described in Monograph Supplement No. 8 of the <i>Psychological -Review</i> under the heading, ‘Animal Intelligence; -an Experimental Study of the Associative Processes in -Animals.’<a id="FNanchor_23" href="#Footnote_23" class="fnanchor">[23]</a> This monograph affords by far the best introduction -to the present discussion, and I shall therefore -assume an acquaintance with it on the part of my readers.</p> - -<p>It will be remembered that evidence was there given that -ordinary mammals, barring the primates, did not infer or -compare, did not imitate in the sense of ‘learning to do an -act from seeing it done,’ did not learn various simple acts -from being put through them, showed no signs of having in -connection with the bulk of their performances any mental -images. Their method of learning seemed to be the gradual -selection of certain acts in certain situations by reason -of the satisfaction they brought. Quantitative estimates -of this gradualness were given for a number of dogs and -cats. Nothing has appeared since the ‘Experimental Study’ -to negate any of these conclusions in the author’s mind. -The work of Kline and Small<a id="FNanchor_24" href="#Footnote_24" class="fnanchor">[24]</a> on rodents shows the same -general aspect of mammalian mentality.</p> - -<p>Adult human beings who are not notably deficient in -mental functions, at least all such as psychologists have -observed, possess a large stock of images and memories. -The sight of a chair, for example, may call up in their minds -a picture of the person who usually sits in it, or the sound -of his name. The sound of a bell may call up the idea of<span class="pagenum"><a id="Page_174"></a>[174]</span> -dinner. The outside world also is to them in large part a -multitude of definite percepts. They feel the environment -as trees, sticks, stones, chairs, tables, letters, words, etc. -I have called such definite presentations ‘free ideas’ to -distinguish them from the vague presentations such as -atmospheric pressure, the feeling of malaise, of the position -of one’s body when falling, etc. It is such ‘free ideas’ -which compose the substance of thought and which -lead us to perhaps the majority of the different acts we -perform, though we do, of course, react to the vaguer sort -as well. I saw definitely in writing the last sentence the -words ‘majority of the different acts’ and thought ‘we -perform’ and so wrote it. I see a bill and so take check -book and pen and write. I think of the cold outside and -so put on an overcoat. This mental function ‘having free -ideas,’ gives the possibility of learning to meet situations -properly by thinking about them, by being reminded of -some property of the fact before us or some element therein.</p> - -<p>We can divide all learning into (1) <i>learning by trial and -accidental success</i>, by the strengthening of the connections -between the sense-impressions representing the situation -and the acts—or impulses and acts—representing our -successful response to it and by the inhibition of similar -connections with unsuccessful responses; (2) <i>learning by -imitation</i>, where the mere performance by another of a -certain act in a certain situation leads us to do the same; -and (3) <i>learning by ideas</i>, where the situation calls up some -idea (or ideas) which then arouses the act or in some way -modifies it.</p> - -<p>The last method of learning has obviously been the means -of practically all the advances in civilization. The evidence -quoted a paragraph or so back from the Experimental -Study shows the typical mammalian mind to be one which<span class="pagenum"><a id="Page_175"></a>[175]</span> -rarely or never learns in this fashion. The present study -of the primates has been a comparative study with two -main questions in view: (1) How do the monkeys vary -from the other mammals in the general mental functions -revealed by their methods of learning? (2) How do they, -on the other hand, vary from adult civilized human beings?</p> - -<p>The experiments to be described seem, however, to be of -value apart from the possibility of settling crucial questions -by means of the evidence they give. To obtain exact -accounts of what animals can learn by their own unaided -efforts, by the example of their fellows or by the tuition -of a trainer, and of how and how fast they learn in each -case, seems highly desirable. I shall present the results -in the manner which fits their consideration as arguments -for or against some general hypotheses, but the naturalist -or psychologist lacking the genetic interest may find an -interest in them at their face value. I shall confine myself -mainly to questions concerning the method of learning of -the primates, and will discuss their sense-powers and unlearned -reactions or instincts only in so far as is necessary -to its comprehension.</p> - -<p>It has been impossible for the author to make helpful -use of the anecdotes and observations of naturalists and -miscellaneous writers concerning monkey intelligence. -The objections to such data pointed out in Chapter II, -<a href="#Page_22">pp. 22-26</a>, hold here. Moreover it is not practicable -to sift out the true from the false or to interpret these -random instances of animal behavior even if assuredly true. -In the study of animal life the part is only clear in the -light of the whole, and it is wiser to limit conclusions to -such as are drawn from the constant and systematic study -of a number of animals during a fairly long time. After -a large enough body of such evidence has been accumulated -we may be able to interpret random observations.</p> - -<p><span class="pagenum"><a id="Page_176"></a>[176]</span></p> - -<p>The subjects of the experiments were three South American -monkeys of the genus <i>Cebus</i>. At the time of beginning -the experiment No. 1 was about half grown, No. 2 was about -one fourth full size and No. 3 was about half grown. No. 1 -was under observation from November, 1899, to February, -1900; No. 2 and No. 3 from October, 1900, to February, -1901. No. 1 was during the period of experimentation -decidedly tame, showing no fear whatever of my presence -and little fear at being handled. He would handle and -climb over me with no hesitation. No. 2 was timid, did -not allow handling, but showed no fear of my presence and -no phenomena that would differentiate his behavior in -the experiments discussed from that of No. 1, save much -greater caution in all respects. No. 3 also showed no fear -at my presence. Any special individual traits that are of -importance in connection with any of the observations will -be mentioned in their proper places. No. 1 was kept until -June, 1900, in my study in a cage 3 by 6 by 6 feet, and was -left in the country till October, 1900. From October, 1900, -all three were kept in a room 8 by 9 feet, in cages 6 feet tall -by 3 long by 2.6 wide for Nos. 1 and 2, 3 feet by 3 feet by 20 -inches for No. 3. I studied their behavior in learning to -get into boxes, the doors to which could be opened by -operating some mechanical contrivance, in learning to -obtain food by other simple acts, in learning to discriminate -between two signals, that is, to respond to each by a different -act, and in their general life.</p> - -<p>Following the order of the ‘Animal Intelligence,’ I shall -first recount the observations of the way the monkeys -learned, solely by their own unaided efforts, to operate -simple mechanical contrivances.</p> - -<p>Besides a number of boxes such as were used with the -dogs and cats (see <a href="#figure01">illustration on p. 30</a>), I tried a variety<span class="pagenum"><a id="Page_177"></a>[177]</span> -of arrangements which could be set up beside a cage, and -which would, when some simple mechanism was set in -action, throw a bit of food into the cage. <a href="#figure26">Figure 26</a> -shows one of these. See description of QQ (ff) on <a href="#Page_182">page 182</a>.</p> - -<div class="figcenter illowp95" id="figure26" style="max-width: 43.75em;"> - <img class="w100" src="images/figure26.jpg" alt=""> - <p class="caption"><span class="smcap">Fig. 26.</span> <i>A</i>, loop; <i>BB</i>, lever, -pivoted at <i>M</i>. A bit of food put in front of <i>C</i> -would be thrown down the chute <i>DDD</i> when <i>A</i> was released.</p> -</div> - -<h3><span class="smcap">Apparatus</span></h3> - -<p>The different mechanisms which I used were the following:—</p> - -<p>Box BB (O at back) was about 20 by 14 by 12 inches with -a door in the front which was held by a bolt to which was -tied a string. This string ran up the front of the box outside, -over a pulley, across the top, and over another pulley -down into the box, where it ended in a loop of wire.</p> - -<p>Box MM (bolt) was the same as BB but with no string -and loop attachment to the bolt.</p> - -<p>Box CC (single bar) was a box of the same size as BB.<span class="pagenum"><a id="Page_178"></a>[178]</span> -The door was held by a bar about 3 by 1 by 5 inches which -swung on a nail at the left side.</p> - -<p>Box CCC (double bar) was CC with a second similar -bar on the right side of the door.</p> - -<p>Box NN (hook) was a box about the size of BB with its -door held by an ordinary hook on the left side which hooked -through an eyelet screwed into the door.</p> - -<p>Box NNN was NN with the hook on the right instead -of the left side.</p> - -<p>Box NNNN was box NN with two hooks, one on each -side.</p> - -<p>Apparatus OO (string box) consisted of a square box tied -to a string, which formed a loop running over a pulley by -the cage and a pulley outside, so that pulling on the under -string would bring the box to the cage. In each experiment -the box was first pulled back to a distance of 2 feet 3 inches -from the cage, and a piece of banana put in it. The monkey -could, of course, secure the banana by pulling the box -near enough.</p> - -<p>Apparatus OOO was the same as OO, with the box tied -to the upper string, so that the upper string had to be pulled -instead of the lower.</p> - -<p>Box PP was about the size of BB. Its door was held by -a large string securely fastened at the right, passing across -the front of the door and ending in a loop which was put -over a nail on the box at the left of the door. By pulling -the string off the nail the door could be opened.</p> - -<p>Box RR (wood plug) was a box about the size of BB. -The door was held by a string at its top, which passed up -over the front and top to the rear, where it was fastened -to a wooden plug which was inserted in a hole in the top of -the box. When the plug was pulled out of the hole, the -door would fall open.</p> - -<p><span class="pagenum"><a id="Page_179"></a>[179]</span></p> - -<p>Box SS (triple; wood-plug, hook and bar) was a box -about the size of BB. To open the door, a bar had to be -pushed around, a hook unhooked and a plug removed from -a hole in the top of the box.</p> - -<p>Box TT (nail plug) was 14 by 10 by 10 inches with a door -5.5 by 10 on the right side of the front, the rest of the front -being barred up. The door was hinged at the bottom and -fastened at its top to a wire which was fastened to a nail -2.5 inches long, which, when inserted in a hole 0.25 inches -in diameter at the back of the top of the box, held the door -closed. By drawing out this nail and pulling the door -the animal could open the door.</p> - -<p>Box VV (plug at side) was a box about 18 by 10 by 10, -the door held by a plug passing through a hole in the side -of the box. When the plug was pulled out, the door could -be pushed inward.</p> - -<p>Box W (loop) was 17 by 10 by 10 inches with a door 5 by 9 -at the left side of its front hinged at the bottom. The door -was prevented from falling inward by a wire stretched -behind it. It was prevented from falling outward by a -wire firmly fastened at the right side and held by a loop over -a nail at the left. By pulling the loop outward and to the -left it could be freed from the nail. The door could then -be pulled open.</p> - -<p>Box WW (bar inside) was 16 by 14 by 10 inches with a -door 4 by 11 at the left of its front hinged at the bottom. -The door could be pushed in or pulled out when a bar on -its inside was lifted out of a latch. The bar was accessible -from the outside through an opening in the front of the -box. It had to be lifted to a height of 1.5 inches (an angle -of about 30°).</p> - -<p>Box XX (bar outside) was about 13 by 11 by 10 inches -with a door 7 by 8 on the left side of the front. The door<span class="pagenum"><a id="Page_180"></a>[180]</span> -was held in place by a bar swinging on a nail at the top, -with its other end resting in a latch at the left side of the -box. By pushing this up through an angle of 45° the door -could be opened.</p> - -<p>Box YY (push bar) was a box 16 by 8 by 12 inches with -a door at the left of its front. The door was held by a brass -bar which swung down in front of an L-shaped piece of -steel fastened to the inside of the door. This brass bar -was hung on a pivot at its center and the other end attached -to a bar of wood; the other end of this bar projected -through a hole at the right side of the box. By pushing -this bar in about an inch the door could be opened.</p> - -<p>Box LL (triple; nail plug, hook and bar) was a box 10 by -10 by 13 with a door 3 by 8.5 at the left side. The door -could be opened only after (1) a nail plug had been removed -from a hole in the back of the top of the box as in TT, (2) a -hook in the door had been unhooked, and (3) a bar on the -left side had been turned from a horizontal to a vertical -position.</p> - -<p>Box Alpha (catch at back) was 11 by 10 by 15 with the -door (4 by 4) in the left side of its front. The door was held -by a bolt, which, when let down, held in a catch on the inside -of the door. A string fastened to the bolt ran across to -the back of the box and through a hole to the outside. -There it ended in a piece of wood 2.5 by 1 by .25 inches. -When this piece of wood was pulled, the bolt went up and -the door fell open.</p> - -<p>Box Beta was the same as NN except in size. It was -10 by 10 by 13 inches.</p> - -<p>Box KK (triple; bolt, side plug, and knob) was a box 16 -by 9 by 11 with a door at the left side of the front. The -door was held by a bolt on the right side, a wooden plug -stuck through a hole in the box on its left side and a nail<span class="pagenum"><a id="Page_181"></a>[181]</span> -which held in a catch at its top. This nail was fastened -to a wooden knob (1 by 5 by .375) which lay in a depression -at the top of the box. Only when the bolt had been -drawn and the plug and knob pulled, could the door be -opened.</p> - -<p>Box Gamma (wind) was 10 by 10 by 13 inches with its -door held by a wire fastened at the top and wound three -times about a screw eye in the top of the box. By unwinding -the wire the door could be opened.</p> - -<p>Box Delta (push back) was 12 by 11 by 10 inches. Its -door was held by a wooden bar projecting from the right -two inches in front of it. This bar was so arranged that -it could be pushed or pulled toward the right, allowing the -door to fall open. It could not be swung up or down.</p> - -<p>Box Epsilon (lever or push down) was 12 by 9 by 5 inches. -At the right side of its front was a hole ½ inch broad by 1½ -inches up and down. Across this hole on the inside of the -box was a strip of brass, the end of one bar of a lever. If -this strip was depressed ⅛ of an inch, the door at the extreme -left would be opened by a spring.</p> - -<p>Box Zeta (side plug) was 12 by 11 by 10 inches. Its door -was held by a round bar of wood put through a hoop of -steel at the left side of the box. This bar was loose and -could easily be pulled out, allowing the door to be opened.</p> - -<p>Box Theta was the same as KK except that the door -could be opened as soon as the bolt alone was pulled or -pushed up.</p> - -<p>Box Eta was like Alpha save that the object at the back -of the box to be pulled was a brass ring.</p> - -<p>Apparatus QQ (chute) consisted of a lever mechanism so -arranged that by pushing in a bar of wood ¼ to ½ an inch, -a piece of banana would be thrown down a chute into the -cage. The apparatus was placed outside the cage in such a<span class="pagenum"><a id="Page_182"></a>[182]</span> -way that it could be easily reached by the monkey’s arm -through the wire netting.</p> - -<p>QQ (a) was of the same general plan. By turning a -handle through 270° food could be obtained.</p> - -<p>QQ (b) was like QQ (a) except that 2½ full revolutions -of the handle in one direction were necessary to cause the -food to drop down.</p> - -<p>QQ (c) was a chute apparatus so arranged as to work when -a nail was pulled out of a hole.</p> - -<p>QQ (d) was arranged to work at a sharp pull upon a brass -ring hanging to it.</p> - -<p>QQ (e) was arranged to work when a hook was unhooked.</p> - -<p>QQ (f) was arranged to work when a loop at the end of a -string was pulled off from a nail.</p> - -<p>QQ (ff) was QQ (f) with a stiff wire loop instead of a loop -of string.</p> - -<h3><span class="smcap">Experiments on the Abilities of the Monkeys to Learn Without Tuition</span></h3> - -<p>I will describe a few of the experiments with No. 1 as -samples and then present the rest in the form of a table. -No. 1 was tried first in BB (O at back) on January 17, 1900, -being <i>put inside</i>. He opened the box by pulling up the -string just above the bolt. His times were .05, 1.38, 6.00, -1.00, .10, .05, .05. He was not easily handled at this time, -so I changed the experiment to the form adopted in future -experiments. I put the food inside and left the animal to -open the door from the outside. He pulled the string up -within 10 seconds each time out of 10 trials.</p> - -<p>I then tried him in MM (bolt). He failed in 15. I then -(January 18th) tried him in CC (single bar outside). He -got in in 36.00 minutes; he did not succeed a second time<span class="pagenum"><a id="Page_183"></a>[183]</span> -that night, but in the morning the box was open. His -times thenceforth were 20, 10, 16, 25 and on January 19th, -40, 5, 12, 8, 5, 5, 5 seconds.</p> - -<p>I then tried him (January 21, 1900) in CCC (double bar). -He did it at first by pushing the old bar and then pulling -at the door until he worked the second bar gradually -around. Later he at times pushed the second bar. The -times taken are shown in the time-curve. I then (January -25th) tried him in NN (hook). See time-curves on -<a href="#Page_185">page 185</a>. I then (January 27th) tried him in NNN (hook -on other side). He opened it in 6, 12 and 4 seconds in the -first three trials. I then (20 minutes later) tried him with -NNNN (double hook). He opened the door in 12, 10, 6 -and 6 seconds. I then (January 27th) tried him with PP -(string across). He failed in 10. I then (February 21st) -tried him with apparatus OO (string box). For his progress -as shown by the times taken see the time-curve. His -progress is also shown in the decrease of the useless pullings -at the wrong string. There were none in the 9th trial, -14th, 15th, 16th, 18th, 24th, and following trials.</p> - -<p>No. 1 was then (February 24th) tried with OOO (string -box with box on upper string). No. 1 succeeded in 2.20, -then failed in 10.00. The rest of the experiment will be -described under imitation.</p> - -<p>He was next tried (March 24th) with apparatus QQ -(chute). He failed in 10.00, though he played with the apparatus -much of the time. Other experiments were with -box RR (wood-plug) (April 5th). He failed in 10.00. -After he had, in a manner to be described later, come to -succeed with RR, he was tried in box SS (triple; wood-plug, -hook and bar) (April 18th); see time-curve. No more -experiments of this nature were tried until October, 1900.</p> - -<p>The rest of the experiments with No. 1 and all those with<span class="pagenum"><a id="Page_184"></a>[184]</span> -No. 2 and No. 3 may best be enumerated in the form of a -table. (See Table 9 on <a href="#Page_187">page 187</a>.) It will show briefly the -range of performances which the unaided efforts of the -animals can cope with. It will also give the order in which -each animal experienced them. F means that the animal -failed to succeed. The figures are minutes and seconds, -and represent the time taken in the first trial or the -total time taken without success where there is an F. In -cases where the animal failed in say 10 minutes, but in a -later trial succeeded, say in 2.40, the record will be 2.40 -after 10 F. There are separate columns for all three animals, -headed No. 1, No. 2 and No. 3. Im. stands for a practically -immediate success.</p> - -<p>The curves on pages 185 and 186 (<a href="#figure27">Figs. 27 and 28</a>) show the -progress of the formation of the associations in those cases -where the animal was given repeated trials, with, however, -nothing to guide him but his own unaided efforts. Each -millimeter on the abscissa represents one trial and each -millimeter on the ordinate represents 10 seconds, the ordinates -representing the time taken by the animal to open -the box. A break in the curve, or an absence of the curve -at the beginning of the base-line represents cases where the -animal failed in 10 minutes or took a very long time to get -out.</p> - -<p><span class="pagenum"><a id="Page_185"></a>[185]</span></p> - -<div class="figcenter illowp48" id="figure27" style="max-width: 28.125em;"> - <img class="w100" src="images/figure27.jpg" alt=""> - <p class="caption"><span class="smcap">Fig. 27.</span></p> -</div> - -<div class="figcenter illowp48" id="figure28" style="max-width: 28.125em;"> - <img class="w100" src="images/figure28.jpg" alt=""> - <p class="caption"><span class="smcap">Fig. 28.</span></p> -</div> - -<p>In discussing these facts we may first of all clear our way -of one popular explanation, that this learning was due to -‘reasoning.’ If we use the word reasoning in its technical -psychological meaning as the function of reaching conclusions -by the perception of relations, comparison and inference, -if we think of the mental content involved as feelings -of relation, perceptions of similarity, general and abstract -notions and judgments, we find no evidence of reasoning<span class="pagenum"><a id="Page_186"></a>[186]</span> -in the behavior of the monkeys toward the mechanisms -used. And this fact nullifies the arguments for reasoning in -their case as it did in the case of the dogs and cats. The -argument that successful dealings with mechanical contrivances -imply that the animals reasoned out the properties -of the mechanisms, is destroyed when we find mere selection -from their general instinctive activities sufficient to cause -success with bars, hooks, loops, etc. There is also in the -case of the monkeys, as in that of the other mammals, positive -evidence of the absence of any general function of reasoning. -We shall find that at least very many simple acts were -not learned by the monkeys in spite of their having seen me -perform them again and again; that the same holds true -of many simple acts which they saw other monkeys do, -or were put through by me. We shall find that after having -abundant opportunity to realize that one signal meant -food at the bottom of the cage and another none, a monkey -would not act from the obvious inference and consistently -stay up or go down as the case might be, but would make -errors such as would be natural if he acted under the growing -influence of an association between sense-impression and -impulse or sense-impression and idea, but quite incomprehensible -if he had compared the two signals and made a -definite inference. We shall find that, after experience -with several pairs of signals, the monkeys yet failed, when -a new pair was used, to do the obvious thing to a rational -mind; viz., to compare the two, think which meant food, -and act on the knowledge directly.</p> - -<p><span class="pagenum"><a id="Page_187"></a>[187]</span></p> - -<h4><span class="smcap">Table 9</span></h4> - -<table class="borders max60"> - <tr> - <th rowspan="2" class="br"></th> - <th colspan="3">No. 1.</th> - <th colspan="3">No. 2.</th> - <th colspan="3">No. 3.</th> - </tr> - <tr> - <th></th> - <th>Min. Sec.</th> - <th></th> - <th></th> - <th>Min. Sec.</th> - <th></th> - <th></th> - <th>Min. Sec.</th> - <th></th> - </tr> - <tr class="new"> - <td>Box TT (nail plug)</td> - <td>Oct. 19, 1900</td> - <td class="tdr">0.40</td> - <td class="tdr"></td> - <td>Oct. 21, 1900</td> - <td class="tdr">14.10</td> - <td class="tdr"></td> - <td>Oct. 21, 1900</td> - <td class="tdr">36.00</td> - <td class="tdr"></td> - </tr> - <tr class="new"> - <td>Box UU (old plug at side)</td> - <td>Oct. 19, 1900</td> - <td class="tdr"></td> - <td class="tdr">F 60.00</td> - <td class="tdr"></td> - <td class="tdr"></td> - <td class="tdr"></td> - <td class="tdr"></td> - <td class="tdr"></td> - <td class="tdr"></td> - </tr> - <tr class="new"> - <td rowspan="3">Box VV (wire loop)</td> - <td rowspan="3" class="nw br">Oct. 20, 1900</td> - <td class="tdr"></td> - <td class="tdr nw">{F 10.00</td> - <td class="nw">Oct. 24, 1900</td> - <td class="tdr"></td> - <td class="tdr nw">F 10.00</td> - <td rowspan="3" class="nw">Oct. 22, 1900</td> - <td class="tdr"></td> - <td class="tdr nw">{F 10.00</td> - </tr> - <tr> - <td class="tdr"></td> - <td class="tdr">{F 10.00</td> - <td>Oct. 25, 1900</td> - <td class="tdr"></td> - <td class="tdr">F 10.00</td> - <td class="tdr"></td> - <td class="tdr">{F 10.00</td> - </tr> - <tr> - <td class="tdr"></td> - <td class="tdr">{F 10.00</td> - <td class="tdr"></td> - <td class="tdr"></td> - <td class="tdr"></td> - <td class="tdr"></td> - <td class="tdr">{F 10.00</td> - </tr> - <tr class="new"> - <td rowspan="4" class="br">Box WW (bar inside)</td> - <td rowspan="4" class="br">Oct. 20, 1900</td> - <td rowspan="4" class="br"></td> - <td rowspan="4" class="tdr br">F 10.00</td> - <td rowspan="4" class="br">Oct. 21, 1900</td> - <td rowspan="4" class="tdr br">5.00</td> - <td rowspan="4" class="tdr br">after<br>F 30.00</td> - <td>Oct. 22, 1900</td> - <td class="tdr"></td> - <td class="tdr">{F 10.00</td> - </tr> - <tr> - <td rowspan="3" class="br">Oct. 24, 1900</td> - <td class="tdr"></td> - <td class="tdr">{F   5.00</td> - </tr> - <tr> - <td class="tdr"></td> - <td class="tdr">{F 10.00</td> - </tr> - <tr> - <td class="tdr"></td> - <td class="tdr">{F 15.00</td> - </tr> - <tr class="new"> - <td>Box XX (bar outside)</td> - <td>Oct. 23, 1900</td> - <td class="tdr">im.</td> - <td class="tdr">after <a id="FNanchor_25" href="#Footnote_25" class="fnanchor">[25]</a><br>F 10.00</td> - <td>Oct. 24, 1900</td> - <td class="tdr">3.40</td> - <td class="tdr"></td> - <td>Oct. 23, 1900</td> - <td class="tdr">.30</td> - <td class="tdr"></td> - </tr> - <tr class="new"> - <td>Box YY (push bar)</td> - <td>Oct. 30, 1900</td> - <td class="tdr">2.00<a id="FNanchor_26" href="#Footnote_26" class="fnanchor">[26]</a></td> - <td class="tdr"></td> - <td class="tdr"></td> - <td class="tdr"></td> - <td class="tdr"></td> - <td class="tdr"></td> - <td class="tdr"></td> - <td class="tdr"></td> - </tr> - <tr class="new"> - <td>Box Beta (single hook)</td> - <td class="tdr"></td> - <td class="tdr"></td> - <td class="tdr"></td> - <td>Oct. 30, 1900</td> - <td class="tdr">9.00</td> - <td class="tdr">after F 10.00 and 10.00</td> - <td>Oct. 24, 1900</td> - <td class="tdr">im.</td> - <td class="tdr"></td> - </tr> - <tr class="new"> - <td>Box LL (triple; nail plug, hook and bar outside)</td> - <td>Nov. 4, 1900</td> - <td class="tdr">16.00<a id="FNanchor_27" href="#Footnote_27" class="fnanchor">[27]</a></td> - <td class="tdr"></td> - <td>Oct. 3, 1900</td> - <td class="tdr">2.00</td> - <td class="tdr"></td> - <td>Nov. 3, 1900</td> - <td class="tdr">1.45</td> - <td class="tdr"></td> - </tr> - <tr class="new"> - <td>Box Alpha (catch at back)</td> - <td>Nov. 5, 1900</td> - <td class="tdr">.35</td> - <td class="tdr"></td> - <td>Oct. 5, 1900</td> - <td class="tdr">6.00</td> - <td class="tdr"></td> - <td>Nov. 5, 1900</td> - <td class="tdr"></td> - <td class="tdr"></td> - </tr> - <tr class="new"> - <td>Box KK (triple; bolt, side-plug and knob)</td> - <td>Nov. 7, 1900</td> - <td class="tdr"></td> - <td class="tdr">F 10.00<br>F 10.00</td> - <td>Oct. 7, 1900</td> - <td class="tdr"></td> - <td class="tdr">F 60.00</td> - <td>Nov. 7, 1900</td> - <td class="tdr"></td> - <td class="tdr">F 10.00</td> - </tr> - <tr class="new"> - <td>Box Theta (bolt at top)</td> - <td>Nov. 19, 1900</td> - <td class="tdr"></td> - <td class="tdr">F 10.00</td> - <td class="tdr"></td> - <td class="tdr"></td> - <td class="tdr"></td> - <td>Jan. 8, 1901</td> - <td class="tdr"></td> - <td class="tdr">F 10.00</td> - </tr> - <tr class="new"> - <td>Box Eta (ring at back)</td> - <td class="nw">Dec. 17, 1900</td> - <td class="tdr">im.</td> - <td class="tdr"></td> - <td class="tdr"></td> - <td class="tdr"></td> - <td class="tdr"></td> - <td class="nw">Dec. 17, 1900</td> - <td class="tdr">4.20</td> - <td class="tdr"></td> - </tr> - <tr class="new"> - <td>App. QQ (push chute)</td> - <td class="tdr"></td> - <td class="tdr"></td> - <td class="tdr"></td> - <td class="tdr"></td> - <td class="tdr"></td> - <td class="tdr"></td> - <td>Dec. 17, 1900</td> - <td class="tdr"></td> - <td class="tdr">F 60.00</td> - </tr> - <tr class="new"> - <td>Box Gamma (wind)</td> - <td>Jan. 3, 1901</td> - <td class="tdr">.20</td> - <td class="tdr"></td> - <td class="tdr"></td> - <td class="tdr"></td> - <td class="tdr"></td> - <td>Jan. 4, 1901</td> - <td class="tdr"></td> - <td class="tdr">F 10.00</td> - </tr> - <tr> - <td></td> - <td class="tdr"></td> - <td class="tdr"></td> - <td class="tdr"></td> - <td class="tdr"></td> - <td class="tdr"></td> - <td class="tdr"></td> - <td class="tdr"></td> - <td class="tdr"></td> - <td class="tdr">F 10.00</td> - </tr> - <tr class="new"> - <td>Box Delta (push back)</td> - <td>Jan. 4, 1901</td> - <td class="tdr"></td> - <td class="tdr">F   5.00<br>F   5.00</td> - <td class="tdr"></td> - <td class="tdr"></td> - <td class="tdr"></td> - <td>Jan. 4, 1901</td> - <td class="tdr">2.10</td> - <td class="tdr">after<a id="FNanchor_28" href="#Footnote_28" class="fnanchor">[28]</a><br>F 10.00</td> - </tr> - <tr class="new"> - <td>App. QQ (a) (bar chute)</td> - <td>Jan. 6, 1901</td> - <td class="tdr">8.00</td> - <td class="tdr"></td> - <td class="tdr"></td> - <td class="tdr"></td> - <td class="tdr"></td> - <td>Jan. 7, 1901</td> - <td class="tdr"></td> - <td class="tdr">F 10.00</td> - </tr> - <tr class="new"> - <td>Box Zeta (new side plug)</td> - <td>Jan. 7, 1901</td> - <td class="tdr">1.10</td> - <td class="tdr">after F   5.00</td> - <td class="tdr"></td> - <td class="tdr"></td> - <td class="tdr"></td> - <td>Jan. 8, 1901</td> - <td class="tdr">.50</td> - <td class="tdr"></td> - </tr> - <tr class="new"> - <td>App. QQ (b) (2½ revolution chute)</td> - <td>Jan. 9, 1901</td> - <td class="tdr">3.00</td> - <td class="tdr"></td> - <td class="tdr"></td> - <td class="tdr"></td> - <td class="tdr"></td> - <td>Jan. 8, 1901</td> - <td class="tdr"></td> - <td class="tdr">F 10.00</td> - </tr> - <tr class="new"> - <td>App. QQ (c) (nail-plug chute)</td> - <td>Jan. 11, 1901</td> - <td class="tdr"></td> - <td class="tdr">F   5.00<br>F   5.00</td> - <td class="tdr"></td> - <td class="tdr"></td> - <td class="tdr"></td> - <td>Jan. 11, 1901</td> - <td class="tdr"></td> - <td class="tdr">F   5.00<br>F   5.00</td> - </tr> - <tr class="new"> - <td>Box Epsilon (push down)</td> - <td>Jan. 12, 1901</td> - <td class="tdr"></td> - <td class="tdr">F   5.00<br>F 10.00</td> - <td class="tdr"></td> - <td class="tdr"></td> - <td class="tdr"></td> - <td>Jan. 12, 1901</td> - <td class="tdr"></td> - <td class="tdr">F 10.00</td> - </tr> - <tr class="new"> - <td>App. QQ (d) (ring chute)</td> - <td>Jan. 16, 1901</td> - <td class="tdr"></td> - <td class="tdr">F   5.00<br>F   5.00</td> - <td class="tdr"></td> - <td class="tdr"></td> - <td class="tdr"></td> - <td>Jan. 16, 1901</td> - <td class="tdr">im.</td> - <td class="tdr"></td> - </tr> - <tr class="new"> - <td>App. QQ (e) (hook chute)</td> - <td class="tdr"></td> - <td class="tdr"></td> - <td class="tdr"></td> - <td class="tdr"></td> - <td class="tdr"></td> - <td class="tdr"></td> - <td>Jan. 16, 1901</td> - <td class="tdr"></td> - <td class="tdr">F   5.00</td> - </tr> - <tr class="new"> - <td>App. QQ (f) (string chute)</td> - <td>Jan. 17, 1901</td> - <td class="tdr"></td> - <td class="tdr">F   5.00</td> - <td class="tdr"></td> - <td class="tdr"></td> - <td class="tdr"></td> - <td class="tdr"></td> - <td class="tdr"></td> - <td class="tdr"></td> - </tr> - <tr class="new"> - <td>App. QQ (ff) (string-wire chute)</td> - <td>Jan. 17, 1901</td> - <td class="tdr">.20</td> - <td class="tdr"></td> - <td class="tdr"></td> - <td class="tdr"></td> - <td class="tdr"></td> - <td>Jan. 19, 1901</td> - <td class="tdr"></td> - <td class="tdr">F   5.00<br>F   5.00</td> - </tr> -</table> - -<p><span class="pagenum"><a id="Page_188"></a>[188]</span></p> - -<p>The methods one has to take to get them to do anything, -their general conduct in becoming tame and in the experiments -throughout, confirm these conclusions. The -following particular phenomena are samples of the many -which are inconsistent with the presence of reasoning as -a general function. No. 1 had learned to open a door by -pushing a bar around from a horizontal to a vertical position. -The same box was then fitted with two bars. He -turned the first bar round thirteen times before attempting -to push the other bar around. In box LL all three monkeys -would in the early trials do one or two of the acts over and -over after they had once done them. No. 1, who had -learned to pull a loop of wire off from a nail, failed thereafter -to pull off a similar loop made of string. No. 1 and No. 3 -had learned to poke their left hands through the cage for -me to take and operate a chute with. It was extremely -difficult to get either of them to put his right hand through -or even to let me take it and pull it through.</p> - -<p>A negative answer to the question “Do the monkeys -reason?” thus seems inevitable, but I do not attach to<span class="pagenum"><a id="Page_189"></a>[189]</span> -the question an importance commensurate with the part -it has played historically in animal psychology. For I -think it can be shown, and I hope in a later monograph -to show, that reasoning is probably but one secondary -result of the general function of having free ideas in great -numbers, one product of a type of brain which works in -great detail, not in gross associations. The denial of reasoning -need not mean, and does not to my mind, any denial -of continuity between animal and human mentality or any -denial that the monkeys are mentally nearer relatives to -man than are the other mammals.</p> - -<p>So much for supererogatory explanation. Let us now -turn to a more definite and fruitful treatment of these -records.</p> - -<p>The difference between these records and those of the -chicks, cats and dogs given on <a href="#Page_39">pages 39-65</a> <i>passim</i> is undeniable. -Whereas the latter were practically unanimous, -save in the cases of the very easiest performances, -in showing a process of gradual learning by a gradual -elimination of unsuccessful movements, and a gradual -reënforcement of the successful one, these are unanimous, -save in the very hardest, in showing a process of sudden -acquisition by a rapid, often apparently instantaneous, -abandonment of the unsuccessful movements and a selection -of the appropriate one which rivals in suddenness the -selections made by human beings in similar performances. -It is natural to infer that the monkeys who suddenly replace -much general pulling and clawing by a single definite -pull at a hook or bar have an idea of the hook or bar and -of the movement they make. The rate of their progress -is so different from that of the cats and dogs that we cannot -help imagining as the cause of it a totally different mental -function, namely, free ideas instead of vague sense-impressions<span class="pagenum"><a id="Page_190"></a>[190]</span> -and impulses. But our interpretation of these results -should not be too hasty. We must first consider several -other possible explanations of the rapidity of learning -by the monkeys before jumping to the conclusion that the -forces which bring about the sudden formation of associations -in human beings are present.</p> - -<p>First of all it might be that the difference was due to the -superiority of the monkeys in clear detailed vision. It -might be that in given situations where associations were -to be formed on the basis of smells, the cats and dogs -would show similar rapid learning. There might be, that is, -no general difference in type of mental functioning, but -only a special difference in the field in which the function -worked. This question can be answered by an investigation -of the process of forming associations in connection with -smells by dogs and cats. Such an investigation will, I -hope, soon be carried on in the Columbia Laboratory by -Mr. Davis.<a id="FNanchor_29" href="#Footnote_29" class="fnanchor">[29]</a></p> - -<p>Secondly, it might be that the superior mobility and more -detailed and definite movements of the monkeys’ hands -might have caused the difference. The slowness in the -case of the dogs and cats might be at least in part the result -of difficulty in executing movements, not in intending them. -This difficulty in execution is a matter that cannot be readily -estimated, but the movements made by the cats and dogs -would not on their face value seem to be hard. They were -mostly common to the animals’ ordinary life. At the same -time there were certain movements (<i>e.g.</i> depressing the -lever) which were much more quickly associated with their -respective situations by the cats than others were, and if -we could suppose that all the movements learned by the -monkeys were comparable to these few, it would detract<span class="pagenum"><a id="Page_191"></a>[191]</span> -from the necessity of seeking some general mental difference -as the explanation of the difference in the results.</p> - -<p>In the third place it may be said by some that no comparison -of the monkeys with dogs and cats is valid, since -the former animals got out of boxes while the latter got in. -It may be supposed that the instinctive response to confinement -includes an agitation which precludes anything save -vague unregulated behavior. Professor Wesley Mills has -made such a suggestion in referring to the ‘Animal Intelligence’ -in the <i>Psychological Review</i>, May, 1899. In the -July number of the same journal I tried to show that -there was no solid evidence of such a harmful agitation. -Nor can we be at all sure that agitation when present does -not rather quicken the wits of animals. It often seems to. -However I should, of course, allow that for purposes of -comparison it would be better to have the circumstances -identical. And I should welcome any antagonist who should, -by making experiments with kittens after the fashion of -these with the monkeys, show that they did learn as suddenly -as the latter.</p> - -<p>Again we know that, whereas the times taken by a cat -in a box to get out are inversely proportional to the strength -of the association, inasmuch as they represent fairly the -amount of its efforts, on the other hand, the times taken by a -monkey to get in represent the amounts of his efforts <i>plus -the amount of time in which he is not trying to get in</i>. It may -be said therefore that the time records of the monkeys prove -nothing,—that a record of four minutes may mean thirty -seconds of effort and three minutes thirty seconds of sleep,—that -one minute may really represent twice as much effort. -As a matter of fact this objection would occasionally hold -against some single record. The earliest times and the -occasional long times amongst very short ones are likely<span class="pagenum"><a id="Page_192"></a>[192]</span> -to be too long. The first fact makes the curves have too -great a drop at the start, making them seem cases of too -sudden learning, but the second fact makes the learning -seem indefinite when it really is not. And in the long run -the times taken do represent fairly well the amount of -effort. I carefully recorded the amount of actual effort -in a number of cases and the story it tells concerning the -mental processes involved is the same as that told by the -time-curves.</p> - -<p>Still another explanation is this: The monkeys learn -quickly, it is true, but not quickly enough for us to suppose -the presence of ideas, or the formation of associations among -them. For if there were such ideas, they should in the complex -acts do even better than they did. The explanation -then is a high degree of facility in the formation of associations -of just the same kind as we found in the chicks, dogs -and cats.</p> - -<p>Such an explanation we could hardly disapprove in any -case. No one can from objective evidence set up a standard -of speed of learning below which all shall be learning without -ideas and above which all shall be learning by ideas. -We should not expect any hard and fast demarcation.</p> - -<p>This whole matter of the rate of learning should be studied -in the light of other facts of behavior. My own judgment, -if I had nothing but these time-curves to rely on, would be -that there was in them an appearance of learning by ideas -which, while possibly explicable by the finer vision and -freer movements of the monkey in connection with ordinary -mammalian mentality, made it worth while to look farther -into their behavior. This we may now do.</p> - -<p>What leads the lay mind to attribute superior mental -gifts to an animal is not so much the rate of learning as -the amount learned. The monkeys obviously form more<span class="pagenum"><a id="Page_193"></a>[193]</span> -associations and associations in a greater variety than do the -other mammals. The improved rate assists, but another -cause of this greater number of associations is the general -physical activity of the monkeys, their constant movements -of the hands, their instinctive curiosity or tendency to fool -with all sorts of objects, to enjoy having sense-impressions, -to form associations because of the resulting sound or sight. -These mental characteristics are of a high degree of importance -from the comparative point of view, but they cannot -be used to prove that the monkeys have free ideas, for a -large number of associations may be acquired after the -purely animal fashion.</p> - -<p>What is of more importance is the actual behavior of the -animals in connection with the boxes. First of all, as has -been stated, all the monkey’s movements are more definite, -he seems not merely to pull, but to pull at, not merely to poke, -but to push at. He seems, even in his general random play, -to go here and there, pick up this, examine the other, etc., -more from having the idea strike him than from feeling like -doing it. He seems more like a man at the breakfast table -than like a man in a fight. Still this appearance may be -quite specious, and I think it is likely to lead us to read -ideational life into his behavior if we are not cautious. -It may be simply general activity of the same sort as the -narrower activities of the cat or dog.</p> - -<p>In the second place the monkeys often make special -movements with a directness which reminds one unavoidably -of human actions guided by ideas. For instance, No. 1 -escaped from his cage one day and went directly across the -room to a table where lay a half of a banana which was in a -very inconspicuous place. It seemed as if he had observed -the banana and acted with the idea of its position fully in -mind. Again, on failing to pull a hook out, No. 1 immediately<span class="pagenum"><a id="Page_194"></a>[194]</span> -applied his teeth, though he had before always -pulled it out with his hand. So again with a plug. It may -be that there is a special inborn tendency to bite at objects -pulled unsuccessfully. If not, the act would seem to show -the presence of the idea ‘get thing out’ or ‘thing come out’ -and associated with it the impulse to use the teeth. We -shall see later, however, that in certain other circumstances -where we should expect ideas to be present and result in -acts they do not.</p> - -<p>The fact is that those features in the behavior of the -monkeys in forming associations between the sight of a box -and the act needed to open it which remind us of learning -by ideas may also be possibly explained by general activity -and curiosity, the free use of the hand, and superior quickness -in forming associations of the animal sort. We must -have recourse to more crucial tests or at least seek evidence -from a number of different kinds of mental performances. -The first of these will naturally be their behavior toward -these same mechanisms after a long time-interval.</p> - -<h4><span class="smcap">The Permanence of Associations in the Case of Mechanisms</span></h4> - -<p>My records are too few and in all but one case after too -short an interval to be decisive on the point of abrupt -transition from failure to success such as would characterize -an animal in whose mind arose the idea of a certain part of -the mechanism as the thing to be attacked or of a certain -movement as the fit one. The animals are all under observation -in the Columbia Laboratory, however, and I -trust that later satisfactory tests may be made. No. 2 -was not included in the tests because he was either unwell -or had become very shy of the boxes, entering them even<span class="pagenum"><a id="Page_195"></a>[195]</span> -when the door was left open only after great delay. The -time-curves for the experiments performed will be found -on <a href="#Page_186">page 186</a> among the others. The figures beside each pair -represent the number of days without practice.</p> - -<p>The records show a decided superiority to those of the -cats and dogs. Although the number of trials in the original -tests were in general fewer in the case of the monkeys, the -retention of the association is complete in 6 cases out of 8 -and is practically so in one case where the interval was -8 months.</p> - -<h4><span class="smcap">Experiments on the Discrimination of Signals</span></h4> - -<p>My experiments on discrimination were of the following -general type: I got the animal into the habit of reacting -to a certain signal (a sound, movement, posture, visual -presentation or what not) by some well-defined act. In -the cases to be described this act was to come down from -his customary positions about the top of the cage, to a place -at the bottom. I then would give him a bit of food. When -this habit was wholly or partly formed, I would begin to -mix with that signal another signal enough like it so that -the animal would respond in the same manner. In the -cases where I gave this signal I would not feed him. I could -then determine whether the animal did discriminate or not, -and his progress toward perfect discrimination in case he did. -If an animal responds indiscriminately to both signals (that -is, does not learn to disregard the ‘no food’ signal) it is -well to test him by using two somewhat similar signals, -after one of which you feed him at one place and after the -other of which you feed him at a different place.</p> - -<p>If the animal profits by his training by acquiring ideas of<span class="pagenum"><a id="Page_196"></a>[196]</span> -the two signals and associates with them ideas of ‘food’ -and ‘no food,’ ‘go down’ and ‘stay still,’ and uses these -ideas to control his conduct, he will, we have a right to -expect, change suddenly from total failure to differentiate -the signals to total success. He will or won’t have the ideas, -and will behave accordingly. The same result could, of -course, be brought about by very rapid association of the -new signal with the act of keeping still, a very rapid inhibition -of the act of going down in response to it by virtue -of the lack of any pleasure from doing so.</p> - -<p>For convenience I shall call the signals after which food -was given <i>yes</i> signals and those after which food was not -given <i>no</i> signals. Signals not described in the text are -shown in <a href="#figure29">Fig. 29</a>, below. The progress of the monkeys in -discriminating is shown by <a href="#figure30">Figs. 30 and 31, on pages 199 -and 201</a>. In <a href="#figure30">Figs. 30 and 31</a> every millimeter along the -horizontal or base line represents 10 trials with the signal. -The heights of the black surface represent the percentages -of <i>wrong</i> responses, 10 mm. meaning 100 per cent of<span class="pagenum"><a id="Page_197"></a>[197]</span> -incorrect responses. Thus the first figure of the set, Left -hand, <i>a</i>, presents the following record: First 10 trials, all -wrong; of next 10, 7 wrong; of next 10, 6 wrong; of next -10, 7; of the next, 9; of the next, 9; of the next, 4; of -the next, none; of the next, 3; of the next, 2, and then -70 trials without an error.</p> - -<div class="figcenter illowp100" id="figure29" style="max-width: 31.25em;"> - <img class="w100" src="images/figure29.jpg" alt=""> - <p class="caption"><span class="smcap">Fig. 29.</span></p> -</div> - -<p>I will describe some of the experiments in detail and then -discuss the graphic presentation of them all.</p> - -<h4><span class="smcap">Experiments with No. 1</span></h4> - -<p>Having developed in No. 1 the habit of coming down -to the bottom of his cage to get a bit of food when he saw -me reach out and take such a bit from my desk, I tested -his ability to discriminate by beginning to use now one hand, -now the other, feeding him only when I used the left. I -also used different sets of words, namely, ‘I will give some -food’ and ‘They shall not have any.’ It will be seen later -that he probably reacted only to the difference of the hands. -The experiment is similar to that described on <a href="#Page_129">pages 129 -and 130</a> of Chapter II. At the beginning, it should be -remembered, No. 1 would come down whichever hand was -used, no matter what was said, except in the occasional -cases where he was so occupied with some other pursuit -as to be evidently inattentive. He did come to associate -the act of going down with the one signal and the act of -staying still or continuing his ordinary movements with -the other signal. His progress in learning to do so is best -seen in the curves of his errors. To the ‘yes’ signal he responded -correctly, except for the occasional lapses which I -just mentioned, from the start and throughout. With -the ‘no’ signal his errors were as shown in <a href="#figure30">Fig. 30</a>, <i>a</i>. The -break in the curve at 110 and 120 is probably not significant<span class="pagenum"><a id="Page_198"></a>[198]</span> -of an actual retrograde as the trials concerned followed an -eight days’ cessation of the experiments.</p> - -<p>I next tried No. 1 with an apparatus exposing sometimes -a card with a diamond-shaped piece of buff-colored paper -on it and sometimes a card with a similar black piece. -The black piece was three fourths of an inch farther behind -the opening than the other. The light color was the ‘yes’ -signal. The error curves for both signals are given, as No. 1 -at the beginning of the experiment did not go down always -(<a href="#figure30">Fig. 30</a>, <i>b</i> and <i>b₁</i>).</p> - -<p>I next tried No. 1 with the same apparatus but exposing -cards with YES and N in place of the buff and black diamonds. -The record of the errors is given in <a href="#figure30">Fig. 30</a>, <i>c</i> and <i>c₁</i>. -At the start he came down halfway very often. This I -arbitrarily scored as an error no matter which signal it -was in response to. It should not be supposed that these -curves represent two totally new associations. It seems -likely that the monkey reacted to the <i>position</i> of the N -card in the apparatus (the same as that of the black diamond -card) rather than to the shape of the letters. On -putting the black diamond in front he was much confused.</p> - -<p>I next gave No. 1 the chance to form the habits of coming -down when I rapped my pencil against the table twice and -of staying where he was when I rapped with it once. He -had 90 trials of each signal but failed to give evidence of -any different associations in the two cases.</p> - -<p>Experiments of this sort were discontinued in the summer. -In October I tried No. 1 with the right and left hand experiment, -he being in a new room and cage, and I being -seated in a different situation. He came down at both signals -and failed to make any ascertainable progress with the -no signal in 80 trials. (October 20-24.)</p> - -<p><span class="pagenum"><a id="Page_199"></a>[199]</span></p> - -<div class="figcenter illowp48" id="figure30" style="max-width: 28.125em;"> - <img class="w100" src="images/figure30.jpg" alt=""> - <p class="caption"><span class="smcap">Fig. 30.</span></p> -</div> - -<p><span class="pagenum"><a id="Page_200"></a>[200]</span></p> - -<p>I then tried him with the black and buff diamonds, the -black being in front (October 25-29). The reaction to the -‘yes’ signal was perfect from the start. The progress with -the ‘no’ signal is shown in <a href="#figure30">Fig. 30</a>, <i>d</i>.</p> - -<p>I then tried him with an apparatus externally of different -size, shape and color from that so far used, showing as the -‘yes’ signal a brown card and as the ‘no’ signal a white -and gold card one half inch farther back in the apparatus. -The ‘yes’ signal was practically perfect from the start. His -progress with the ‘no’ signal is shown in <a href="#figure30">Fig. 30</a>, <i>e</i>.</p> - -<p>I then tried a still different arrangement for exposure, to -which, however, he did not give uniform attention.</p> - -<p>I then tried cards 1 and 101, 101 being in front and 1 in -back. 1 was the ‘yes’ signal. ‘Yes’ responses were perfect -from the start. For ‘no’ responses see <a href="#figure30">Fig. 30</a>, <i>f</i>. I then put -the ‘yes’ signal in front and the ‘no’ signal behind. ‘Yes’ -responses perfect; for ‘no’ responses see <a href="#figure30">Fig. 30</a>, <i>f</i>, <i>a</i>.</p> - -<p>From now on I arranged the exposures in such a way that -there was no difference between the ‘yes’ and ‘no’ signals -in distance or surroundings.</p> - -<p>The following list shows the dates, signals used, and the -figures on <a href="#Page_199">page 199</a> presenting the results. Where there is -only one figure drawn, it refers to progress with the ‘no’ -signal, the ‘yes’ signal being practically perfect from the start.</p> - -<h5><span class="smcap">Table 10</span></h5> - -<table class="borders"> - <tr> - <th></th> - <th><span class="smcap">‘Yes’ Signal</span></th> - <th><span class="smcap">‘No’ Signal</span></th> - <th><span class="smcap">Figure</span></th> - </tr> - <tr> - <td>Nov. 13-15, 1900.</td> - <td class="tdr">2</td> - <td class="tdr">102</td> - <td><i>g g₁</i></td> - </tr> - <tr> - <td>Nov. 14-16, 1900.</td> - <td class="tdr">3</td> - <td class="tdr">103</td> - <td><i>i i₁</i></td> - </tr> - <tr> - <td>Nov. 16-19, 1900.</td> - <td class="tdr">4</td> - <td class="tdr">104</td> - <td><i>h</i></td> - </tr> - <tr> - <td>Nov. 19, 1900.</td> - <td class="tdr">5</td> - <td class="tdr">105</td> - <td><i>j</i></td> - </tr> - <tr> - <td>Nov. 20, 1900.</td> - <td class="tdr">6</td> - <td class="tdr">106</td> - <td><i>k</i></td> - </tr> - <tr> - <td>Nov. 21, 1900.</td> - <td class="tdr">7</td> - <td class="tdr">107</td> - <td><i>l</i></td> - </tr> - <tr> - <td>Nov. 23(?), 1900.</td> - <td class="tdr">8</td> - <td class="tdr">108</td> - <td><i>m</i></td> - </tr> - <tr> - <td>Nov. 27-29, 1900.</td> - <td class="tdr">9</td> - <td class="tdr">109</td> - <td><i>n</i></td> - </tr> - <tr> - <td>Nov. 30, 1900.</td> - <td class="tdr">10</td> - <td class="tdr">110</td> - <td><i>o</i></td> - </tr> -</table> - -<p><span class="pagenum"><a id="Page_201"></a>[201]</span></p> - -<p><a href="#figure29">Fig. 29</a> gives facsimiles of the different signals reduced to -one sixth their actual size. The drawing of 101 is not accurate, -the outer ring being too thick.</p> - -<h4><span class="smcap">Experiments with No. 2</span></h4> - -<div class="figcenter illowp75" id="figure31" style="max-width: 25em;"> - <img class="w100" src="images/figure31.jpg" alt=""> - <p class="caption"><span class="smcap">Fig. 31.</span></p> -</div> - -<p>I first secured the partial formation of the habit of coming -down when I took a bit of food in my hand. I then used the -apparatus for exposing cards, YES in front being the ‘yes’ -signal and a circle at the back being the ‘no’ signal. I gave -No. 2 25 trials with the ‘yes’ signal and then began a regular -experiment similar to those described. After about 90 trials -(November 9-12, 1900) there was no progress toward differentiation -of response, and it was evident from No. 2’s behavior -that he was reacting solely to the movements of my -hand. So I abandoned the exposing apparatus and used -(November 11-13, 1900) as the ‘yes’ signal the act of taking -the food with my left hand from a pile on the front of the box -and for the ‘no’ signal the act of taking food with my right -hand from a pile 4 inches behind that just mentioned.<span class="pagenum"><a id="Page_202"></a>[202]</span> -No. 2 did come to differentiate these two signals. The record -of his progress is given in <a href="#figure31">Fig. 31</a> by <i>A</i> and <i>A₁</i>.</p> - -<p>I then made a second attempt with the exposing apparatus, -using cards 2 and 102 (November 6, 14-21). No. 2 -did react to my movements in pulling the string but in over -100 trials made no progress in the direction of a differential -reaction to the ‘no’ signal. I then tried feeding him at each -signal, feeding him at the bottom of the cage as usual when -I gave the ‘yes’ signal and at the top when I gave the ‘no’ -signal. After a hundred trials with the ‘no’ signal there -was no progress.</p> - -<p>I then abandoned again the exposing apparatus and used -as signals the ordinary act of taking food with my left hand -(yes) and the act of moving my left arm from my right side -round diagonally (swinging it on my elbow as a center) and -holding the hand, after taking the food, <i>palm up</i> (no) (November -26, 27, 1900). No. 2 did come to differentiate these -signals. His progress is given in the diagram in <a href="#figure31">Fig. 31</a> entitled -‘Palm up’ (<i>B</i>).</p> - -<p>I next used (November 27, 1900) as the ‘yes’ signal the -same act as before and for the ‘no’ signal the act of holding -the food just in front of the box about four inches below -the edge. No. 2’s progress is shown in <a href="#figure31">Fig. 31</a> in the diagram -entitled ‘low front’ (<i>C</i> and <i>C₁</i>).</p> - -<p>I next used (November 27-30) the same movement for -both ‘yes’ and ‘no’ signals save that as the ‘yes’ signal I took -the food from a brown pasteboard box 3 by 3 by 0.5, and as -the ‘no’ signal I took it from a white crockery cover two -inches in diameter and three eighths of an inch high which -was beside the box but three inches nearer me. No. 2’s -progress is shown in <a href="#figure31">Fig. 31</a> in the diagram entitled ‘Box -near’ (<i>D</i>).</p> - -<p>I next used for the ‘yes’ signal the familiar act and for the<span class="pagenum"><a id="Page_203"></a>[203]</span> -‘no’ signal the act of holding the food six inches above the -box instead of a quarter or a half an inch. The progress is -shown in <a href="#figure31">Fig. 31</a>, <i>E</i> and <i>E₁</i>. I then tried taking the food -from a saucer off the front of the box for the ‘yes’ signal and -from a small box at the back for the ‘no’ signal. ‘Yes’ was -perfect from the start (10 trials given). ‘No’ was right -once, then wrong once, then right for the remaining eight.</p> - -<h4><span class="smcap">Experiments with No. 3</span></h4> - -<p>No. 3 was kept in a cage not half so big as those of 1 and 2. -Perhaps because of the hindrance this fact offered to forming -the habit of reacting in some definite way to ‘yes’ signals, -perhaps because of the fact that I did not try hand movements -as signals, there was no successful discrimination by -No. 3 of the yellow from the black diamond or of a card with -YES from a card with a circle on it. I tried climbing up to -a particular spot as the response to the ‘yes’ signal and staying -still as the response to the ‘no’ signal. I also tried instead -of the latter a different act, in which case the animal -was fed after both signals but in different places. In the -latter case No. 3 made some progress, but for practical -reasons I postponed experiments with him. Circumstances -have made it necessary to postpone such experiments indefinitely.</p> - -<h4><span class="smcap">Permanence of the Ability to Discriminate</span></h4> - -<p>No. 1 and No. 2 were tried again after intervals of 33 to 48 -days. The results of these trials are shown in <a href="#figure32">Fig. 32</a>. Here -every millimeter along the base line represents <i>one</i> trial with -the ‘no’ signal (the ‘yes’ signals were practically perfect), -and failure is represented by a column 10 mm. high while<span class="pagenum"><a id="Page_204"></a>[204]</span> -success is represented by the absence of any column. Thus -the first record reads, “No. 1 with signal 104 after 40 days -made 5 failures, then 2 -successes, then 1 failure, -then 1 success, -then 3 failures, then 1 -success, then 1 failure, -then 3 successes, then -1 failure, then 10 successes.” -The third -record (106; 40 days) -reads, “perfect success -in ten trials.”</p> - -<div class="figcenter illowp48" id="figure32" style="max-width: 18.75em;"> - <img class="w100" src="images/figure32.jpg" alt=""> - <p class="caption"><span class="smcap">Fig. 32.</span></p> -</div> - -<h4><span class="smcap">Discussion of Results</span></h4> - -<p>The results of all -these discrimination -experiments emphasize -the rapidity of formation -of associations -amongst the monkeys, -which appeared in their -behavior toward the -mechanisms. The suddenness of the change in many cases -is immediately suggestive of human performances. If all -the records were like c, f, h, i, j, k, l, m, B, E, and memory -trials 103, A, B, and C, one would have to credit the animals -with either marvelous rapidity in forming associations of -the purely animal sort or concede that from all the objective -evidence at hand they were shown to learn as human beings -would. One would have to suppose that they had clear<span class="pagenum"><a id="Page_205"></a>[205]</span> -ideas of the signals and clean-cut associations with those -ideas. The other records check such a conclusion.</p> - -<p>In studying the figures we should remember that occasional -mistakes, say 1 in 10 trials, are probably not significant -of incomplete learning but of inattention or of precipitate -action before the shutter had fairly exposed the card. We -must not expect that a monkey who totally fails to discriminate -will <i>always</i> respond wrongly to the ‘no’ signal, or that -a monkey who has come to discriminate perfectly will <i>always</i> -respond rightly. A sudden drop from an average high level -of error to an average low level will signify sudden learning. -Where the failure was on the first trial of a series a few hours -or a day removed from the last series, I have generally represented -the fact not by a column 1 mm. high and 1 mm. -broad, but by a single 10 mm. perpendicular. See i and A. -Such cases represent probably the failure of the animal to -keep his learning permanent rather than any general inability -to discriminate.</p> - -<p>K was to some extent a memory trial of d (after over half -a year).</p> - -<p>The experiment with 10 and 110 is noteworthy. Although, -as can be seen from the figures, the difference is obvious -to one looking at the white part of the figure, it is not -so to one looking at the black part. No. 1 failed to improve -appreciably in fifty trials, probably because his previous -experience had gotten him into the habit of attending to the -black lines.</p> - -<p>Before arguing from the suddenness of the change from -failure to success we have to consider one possibility that I -have not mentioned, and in fact for the sake of clearness in -presentation have rather concealed. It is that the sudden -change in the records, which report only whether the animal -did or did not go down, may represent a more gradual<span class="pagenum"><a id="Page_206"></a>[206]</span> -change in the animal’s mind, a gradual weakening of the -impulse to go down which makes him feel less and less inclined -to go down, though still doing so, until this weakening -reaches a sort of saturation point and stops the action. -There were in their behavior some phenomena which might -witness to such a process, but their interpretation is so dependent -on the subjective attitude and prepossessions of the -observer that I prefer not to draw any conclusions from -them. On the other hand, records c, g, n, A and D seem -to show that gradual changes can be paralleled by changes -in the percentage of failures.</p> - -<p>In the statement of conclusions I shall represent what -would be the effect on our theory of the matter in both cases, -(1) taking the records to be fairly perfect parallels of the -process, and (2) taking them to be the records of the summation -points of a process not shown with surety in any measurable -objective facts. But I shall leave to future workers -the task of determining which case is the true one.</p> - -<p>If we judge by the objective records themselves, we may -still choose between two views. (1) We may say that the -monkeys did come to have ideas of the acts of going down to -the bottom of the cage and of staying still, and that their -learning represented the association of the sense-impressions -of the two signals, one with each of these ideas, or possibly -their association with two other ideas (of being fed -and of not being fed), and through them with the acts. Or -(2) we may say that the monkeys had no such ideas, but -merely by the common animal sort of association came to -react in the profitable way to each signal.</p> - -<p>If we take the first view, we must explain the failure of the -animals to change suddenly in some of the experiments, -must explain why, for instance, No. 1 in g should, after he had -responded correctly to the ‘no’ signal for 27 trials out of 30,<span class="pagenum"><a id="Page_207"></a>[207]</span> -fail in one trial out of four for a hundred or more trials. If -the 27 successes were due to ideas, why was there regression? -If the animal came to respond by staying still on seeing the -K (card 104), because that sight was associated with the idea -of no food or the idea of staying still, why did he, in his -memory trial, act sometimes rightly, sometimes wrongly, for -eleven trials after his acting rightly twice. If he stayed still -because the idea was aroused, why did he not stay still as -soon as he had a few trials to remind him of the idea? It is -easy, one may say, to see why, with a capacity to select -movements and associate them with sense-presentations -very quickly, in cases where habit provides only two movements -for selection and where the sense-presentation is very -clear and simple, an animal should practically at once be -confirmed in the one act on an occasion when he does it -with the sense-impression in the focus of attention. It is -easy, therefore, to explain the sudden change in i, l, m, B, C -and E. But our critic may add, “It is very hard to suppose -that an animal that learned by connecting the sight of a card -with the idea ‘stay still’ or the idea ‘no food,’ should be so -long in making the connection as was the case in some of -these experiments, should take 10, 20 or 40 trials to change -from a high percentage of wrong to a high percentage of -right reactions.”</p> - -<p>If we take the second view, we have to face the fact that -many of the records are nothing like the single one we have -for comparison, that of the kitten shown in <a href="#figure30">Fig. 30</a>, and that -the appeal to a capacity to form animal associations very -quickly seems like a far-fetched refuge from the other view -rather than a natural interpretation. If we take the records -to be summation points in a more gradual process, this -difficulty is relieved.</p> - -<p>If further investigation upheld the first view, we should<span class="pagenum"><a id="Page_208"></a>[208]</span> -still not have a demonstration that the monkeys habitually -did learn by getting percepts and images associated with -sense-impressions, by having free ideas of the acts they performed; -we should only have proved that they could under -certain circumstances.</p> - -<p>The circumstances in these experiments on discrimination -were such as to form a most favorable case. The act of -going down had been performed in all sorts of different connections -and was likely to gain representation in ideational -life; the experience ‘bit of banana’ had again been attended -to as a part of very many different associations and so would -be likely to develop into a definite idea.</p> - -<p>These results then do not settle the choice between three -theories: (1 <i>a</i>) that they were due to a general capacity for -having ideas, (1 <i>b</i>) that they were due to ideas acquired by -specially favoring circumstances, (2) that they were due to -the common form of association, the association of an impulse -to an act with a sense-impression rather roughly felt.</p> - -<p>It would be of the utmost interest to duplicate these experiments -with dogs, cats and other mammals and compare -the records. Moreover, since we shall find (1 <i>a</i>) barred out -by other experiments, it will be of great interest to test the -monkeys with some other type of act than discrimination -to see if, by giving the animal experience of the act and result -involved in many different connections, we can get a rate -of speed in the formation of a new association comparable to -the rates in some of these cases.</p> - -<p>Of course here, as in our previous section, the differences -in the sense-powers of the monkeys from those of the kitten -which I have tested with a similar experiment may have -caused the difference in behavior. Focalized vision lends -itself to delicate associations. Perhaps if one used the sense -of smell, or if the dogs and cats could, preserving their same<span class="pagenum"><a id="Page_209"></a>[209]</span> -mental faculties in general, add the capacity for focalized -vision, they would do as well as the monkeys.</p> - -<h3><span class="smcap">Experiments on the Influence of Tuition</span></h3> - -<p>The general aim of these experiments was to ascertain -whether the monkeys’ actions were at all determined by the -presence of free ideas and if so, to what extent. The question -is, “Are the associations which experience leads them to -form, associations between (1) the idea of an object and (2) -the idea of an act or result and (3) the impulses and act itself, -or are they merely associations between the sense-impression -of the object and the impulse and act?” Can a monkey -learn and does he commonly learn to do things, not by -the mere selection of the act from amongst the acts done by -him, but by getting some idea and then himself providing -the act because it is associated in his mind with that idea. -If a monkey feels an impulse to get into a box, sees his arm -push a bar and sees a door fall open immediately thereafter -and goes into the box enough times, he has every chance to -form the association between the impulse to get into the -box and the idea ‘arm push bar,’ provided he can have such -an idea. If his general behavior is due to having ideas -connected with and so causing his acts, he has had chance -enough to form the association between the idea ‘push at’ -and the act of pushing. If then a monkey forms an association -leading to an act by being put through the act, we -may expect that he has free ideas. And if he has free ideas -in general in connection with his actions, we may expect him -to so form associations. So also if a monkey shows a general -capability to learn from seeing another monkey or a -human being do a thing. A few isolated cases of imitation, -however, might witness not to any general mental quality,<span class="pagenum"><a id="Page_210"></a>[210]</span> -but only to certain instincts or habits differing from others -only in that the situation calling forth the act was the same -act performed by another.</p> - -<p>If the monkeys do not learn in these ways, we must, until -other evidence appears, suppose them to be in general destitute -of a life of free ideas, must regard their somewhat ambiguous -behavior in learning by their own unaided efforts -as of the same type as that of the dogs and cats, differing -only in the respects mentioned on <a href="#Page_190">pages 190 and 191</a>.</p> - -<p>The general method of experimentation was to give monkeys -who had failed of their own efforts to operate some -simple mechanism, a chance to see me do it or see another -monkey do it or to see and feel themselves do it, and then -note any change in their behavior. The chief question is -whether they succeed after such tuition when they have -failed before it, but the presence of ideas would also be -indicated if they attacked, though without success, the -vital point in the mechanism when they had not done so -before. On the other hand, mere success would not prove -that the tuition had influenced them, for if they made a different -movement or attacked a different spot, we could not -attribute their behavior to getting ideas of the necessary act.</p> - -<p>The results of the experiments as a whole are on their face -value a trifle ambiguous, but they surely show that the monkeys -in question had no considerable stock of ideas of the -objects they dealt with or of the movements they made and -were not in general capable of acquiring, from seeing me or -one of their comrades attack a certain part of a mechanism -and make a certain movement, any ideas that were at all -efficacious in guiding their conduct. They do not acquire -or use ideas in anything that approaches the way human -adults do. Whether the monkeys may not have some few -ideas corresponding to habitual classes of objects and acts<span class="pagenum"><a id="Page_211"></a>[211]</span> -is a different question. Such may be present and function -as the excitants of acts.</p> - -<p>It is likely that this question could have been definitely -solved if it had been possible for me to work with a larger -number of animals. With enough subjects one could use -the method mentioned on <a href="#Page_105">page 105</a> of Chapter II, of -giving the animals tuition in acts which they would -eventually do themselves without it, and then leaving them -to their efforts, noting any differences in the way they -learned from that in which other subjects who had no tuition -learned the same acts. The chief of such differences to -note would be differences in the time of their first trial, in the -slope of the time-curve and in the number of useless acts.</p> - -<p>It would also be possible to extend experiments of the -type of the (on chair) experiment, where a subject is given -first a certain time (calculated by the experimenter to be -somewhat less than would be needed for the animal to hit -upon the act) and if he does fail is then given certain tuition -and then a second trial. The influence of the tuition is estimated -by the presence or absence of cases where after tuition -the act is done within the time.</p> - -<p>There is nothing necessarily insoluble in the problem. -Given ten or twenty monkeys that can be handled without -any difficulty and it could be settled in a month.</p> - -<p>With this general preface we may turn to the more special -questions connected with the experiments on imitation of -human acts and of the acts of other monkeys and on the formation -of associations apart from the selection of impulses.</p> - -<h4><span class="smcap">Imitation of Human Beings</span></h4> - -<p>It has been a common opinion that monkeys learned -to do things from seeing them done by human beings.<span class="pagenum"><a id="Page_212"></a>[212]</span> -We find anecdotes to that effect in fairly reputable -authors.</p> - -<p>Of course, such anecdotes might be true and still not prove -that the animals learned to do things because they saw them -done. The animal may have been taught in other ways to -respond to the particular sights in question by the particular -acts. Or it may have been in each case a coincidence.</p> - -<p>If a monkey did actually form an association between a -given situation and act by seeing some one respond to that -situation by that act, it would be evidence of considerable -importance concerning his general mental status, for it -would go to show that he could and often did form associations -between sense-impressions and ideas and between -ideas and acts. Seeing some one turn a key in a lock might -thus give him the idea of turning or moving the key, and this -idea might arouse the act. However, the mere fact that a -monkey does something which you have just done in his -presence need not demonstrate or even render a bit more -probable such a general mental condition. For he perhaps -would have acted in just the same manner if you had offered -him no model. If you put two toothpicks on a dish, take -one and put it in your mouth, a monkey will do the same, not -because he profits by your example, but because he instinctively -puts nearly all small objects in his mouth. Because -of their general activity, their instinctive impulses to -grab, drop, bite, rub, carry, move about, turn over, etc., any -novel object within their reach, their constant movement -and assumption of all sorts of postures, the monkeys perform -many acts like our own and simulate imitation to a far -greater extent than other mammals.</p> - -<p>Even if a monkey which has failed of itself to do a certain -thing does it after you have shown him the act, there need -be no reason to suppose that he is learning by imitation,<span class="pagenum"><a id="Page_213"></a>[213]</span> -forming an association between the sight of the object and -the act towards it through an idea gained from watching -you. You may have caused his act simply by attracting his -attention to the object. Perhaps if you had pointed at it or -held it passively in your hand, you would have brought to -pass just the same action on his part. There are several -cases among my records where an act which an animal failed -totally to do of himself was done after I had so attracted his -attention to the object concerned.</p> - -<p>Throughout all the time that I had my monkeys under observation -I never noticed in their general behavior any act -which seemed due to genuine imitation of me or the other -persons about. I also gave them special opportunities to -show such by means of a number of experiments of the following -type: where an animal failed by himself to get into -some box or operate some mechanism, I would operate it in -his presence a number of times and then give him a chance to -profit by the tuition. His failure might be due to (1) the -absence of instinctive impulses to make the movement in -that situation, (2) to lack of precision in the movement, (3) -to lack of force, or (4) to failure to notice and attack some -special part of the mechanism. An instance of (1) was the -failure to push away from them a bar which held a door; -an instance of (2) was the failure to pull a wire loop off a -nail; an instance of (2) or (3) was the failure to pull up a -bolt; an instance of (4) was the failure to pull up an inside -bar. Failures due to (3) occur rarely in the case of such -mechanisms as were used in my investigations.</p> - -<p>The general method of experiment was to make sure that -the animal would not of itself perform a certain act in a certain -situation, then to make sure that his failure could not -be remedied by attracting his attention to the object, then -to perform the act for him a number of times, letting him get<span class="pagenum"><a id="Page_214"></a>[214]</span> -each time the food which resulted, and finally to see whether, -having failed before the tuition, he would succeed after it. -This sounds very simple, but such experiments are hard to -carry out satisfactorily. If you try the animal enough times -by himself to make quite sure that he will not of himself hit -upon the act, you are likely to form in him the habit of -meeting the particular situation in question with total disregard. -His efforts having failed so often may be so inhibited -that you could hardly expect any tuition to give -them new life. The matter is worse if you add further -enough trials to assure you that your attracting his attention -to it has been unavailing. On the other hand, if you -take failure in five or ten minutes to mean inability, and -from subsequent success after imitation argue that imitation -was efficient, you have to face the numerous cases where -animals which have failed in ten minutes have succeeded in -later unaided trials. With dogs and cats this does not much -matter, because they are steady performers, and their conduct -in one short trial tells you what to expect with some probability. -But the monkeys are much more variable and are -so frequently distracted that one feels much less confidence -in his predictions. Moreover, you cannot be at all sure of -having attracted a monkey’s attention to an object unless he -does touch it. Suppose, for example, a monkey has failed -to even touch a bar though you have put a bit of food on it -repeatedly. It is quite possible that he may look at and -take the food and not notice the bar, and the fact that after -such tuition he still fails to push or pull the bar may mean -simply that it has not caught his notice. I have, therefore, -preferred in most cases to give the animals only a brief -period of trial to test their ability by their own unaided -efforts and to omit the attempts to test the efficacy of attracting -their attention to the vital point in the mechanism.<span class="pagenum"><a id="Page_215"></a>[215]</span> -This makes the results appear less elegant and definitive but -really increases their value for purposes of interpretation.</p> - -<p>The thoughtful reader will not expect from my experiments -any perfectly rigorous demonstration of either the -presence or the absence of imitation of human acts as a -means of learning. The general trend of the evidence, it -seems to me, is decidedly towards justifying the hypothesis -that the monkeys did not learn acts from seeing me do -them.</p> - -<p>I will first describe a sample experiment and then present -a summary of all those made.</p> - -<p>On January 12th I put box Epsilon (push down) in No. -3’s cage, the door of the box being open. I put a bit of food -in the box. No. 3 reached in and took it. This was repeated -three times. I then put in a bit of food and closed the -door. No. 3 pulled and bit the box, turned it over, fingered -and bit at the hole where the lever was, but did not succeed -in getting the door open. After ten minutes I took the box -out. Later I took No. 3 out and let him sit on my knees (I -sitting on the floor with the box in front of us). I would -then put my hand out toward the box and when he was -looking at it would insert my finger and depress the lever -with as evident a movement as I could. The door, of -course, opened, and No. 3 put his arm in and took the -bit of food. I then put in another, closed the door and depressed -the lever as before. No. 3 watched my hand pretty -constantly, as all his experiences with me had made such -watching profitable. After ten such trials he was put back -in the cage and the box put in with a large piece of food in it -and its door closed. No. 3 failed in five minutes and the -box was taken out. He was shown fifteen times more and -then left to try himself. I tried him for a couple of minutes -under just the same circumstances as existed during the<span class="pagenum"><a id="Page_216"></a>[216]</span> -tuition, <i>i.e.</i> he on the floor by me, the box in front. In this -trial and in a five-minute trial inside his cage he failed to -open the door or to differ in any essential respect from his -behavior before tuition.</p> - -<p>No. 1 saw me do 9 different acts and No. 3, 7, which they -had failed of themselves to do.<a id="FNanchor_30" href="#Footnote_30" class="fnanchor">[30]</a> After from 1 to 40 chances -to imitate me they still failed to operate at all 11 of these -mechanisms. In the case of 3 out of 5 that were worked -the act was not the same as that taught. No. 1, who saw -me pull a nail out by taking the end of it and pulling the nail -away from the box, himself put his hand round the nail and -wriggled it out by pulling his hand back and forth. No. 3, -who saw me pull a bolt up with my fingers, succeeded by -jerking and yanking the door until he shook the bolt up. -He saw me pull a hook out of an eye, but he succeeded by -pulling at a bar to which it was attached. In the case of -one of the two remaining acts (No. 3 with <i>nail chute</i>) the act -was done once and never again, though ample opportunity -was given and tuition continued. It could, therefore, -hardly have been due to an idea instilled by the tuition. -The remaining case, No. 1, with loop, must, I think, be attributed -to accident, especially since No. 3 failed to profit<span class="pagenum"><a id="Page_217"></a>[217]</span> -by precisely the same sort of tuition with precisely the same -act.</p> - -<p>Nor is there any evidence to show that although tuition -failed to cause successes where unaided effort failed, it yet -caused attempts which would not otherwise have occurred. -Out of fifteen cases where such might have appeared, there -were only three where it is possible to claim that they did. -No one of these three is a sure case. With RR (wood plug) -No. 1 did seem to pull the plug more definitely after seeing -me than before. With QQ (c) (nail chute) and MM (bolt -at top) he may possibly have done so.</p> - -<p>In 5 cases I tried the influence of seeing me make the -movement on animals who had done the act of themselves, -the aim being to see whether there would be a marked shortening -of the time, a change in their way of operating the -mechanism or an attempt at such change. I will give the -essential facts from the general table on <a href="#Page_226">pages 226-229</a>.</p> - -<p>(<i>a</i>) No. 1 had succeeded in pulling in the box by the upper -string in OOO (upper string box) in 2.20 and then failed in -3.00. I showed him 4 times. He failed in 10. I showed -him 4 more times. He failed in 10. I showed him 4 more -times. He succeeded in .20. No change in manner of act or -objects attacked, though my manner was different from his.</p> - -<p>(<i>b</i>) No. 1 had succeeded in QQ (a) (chute bar) in 8.00. I -showed him 20 times. He failed in 10. I showed him 10 -more times. He succeeded in 2.00. I showed him 10 more -times. He succeeded in 50 seconds. No change in his -manner of performance or in the object attacked, though my -manner was different from his.</p> - -<p>(<i>c</i>) No. 1 had succeeded in 3.00, .25, .07, .25, .20, .06 and -.09 with QQ (b) (chute bar double) and then failed in 5.00. -I showed him 10 times. He then failed in 5 twice, succeeded -in 3.00, and failed in 5 again. No change in manner of performance<span class="pagenum"><a id="Page_218"></a>[218]</span> -or in the object attacked, though my manner was -different from his.</p> - -<p>(<i>d</i>) No. 3 had the following record in box Delta:—</p> - -<table> - <tr> - <td class="tdr">2.00</td> - <td>(pushed with head)</td> - </tr> - <tr> - <td class="tdr">3.20</td> - <td>(pushed with head)</td> - </tr> - <tr> - <td class="tdr">30</td> - <td>F</td> - </tr> - <tr> - <td class="tdr">10</td> - <td>F</td> - </tr> - <tr> - <td class="tdr">10</td> - <td>F</td> - </tr> - <tr> - <td class="tdr">2.10</td> - <td>(pulled wire and door).</td> - </tr> -</table> - -<p>I showed him 20 times by pushing the bar to the right with -my finger. He succeeded in 8.00 and 8.00 by pulling the -wire and the door. No change in object attacked.</p> - -<p>(<i>e</i>) No. 2 had failed twice in 5 with chute QQ (ff) (chute -string wire) and succeeded once in 2.00 by a strong pull on -the wire itself, not the loop. I showed him 5 times, pulling -the loop off the nail. He then failed in 5. There was no -change in the objects attacked.</p> - -<p>These records show no signs of any influence of the tuition -that are not more probably signs of something else. We -cannot attribute the rapid decrease in time taken in (<i>b</i>) to -the tuition until we know the time-curve for the same -process without tuition.</p> - -<p>The systematic experiments designed to detect the presence -of ability to learn from human beings are thus practically -unanimous against it. So, too, was the general behavior -of the monkeys, though I do not consider the failure of the -animals to imitate common human acts as of much importance -save as a rebuke to the story-tellers and casual observers. -The following facts are samples: The door of No. -1’s cage was closed by an iron hoop with a slit in it through -which a staple passed, the door being held by a stick of wood -thrust through the staple. No. 1 saw me open the door of<span class="pagenum"><a id="Page_219"></a>[219]</span> -his and other cages by taking out sticks hundreds of times, -but though he escaped from his cage a dozen times in other -ways, he never took the stick out and to my knowledge never -tried to. I myself and visitors smoked a good deal in the -monkeys’ presence, but a cigar or cigarette given to them -was always treated like anything else.</p> - -<h4><span class="smcap">Imitation of Other Monkeys</span></h4> - -<p>It would theoretically seem far more likely that the monkeys -should learn from watching each other than from watching -human beings, and experimental determinations of such -ability are more important than those described in the last -section as contributions both to genetic psychology and to -natural history. I regret that the work I have been able to -do in the study of this phase of the mental life of the monkeys -has been very limited and in many ways unsatisfactory.</p> - -<p>We should expect to find the tendency to imitation more -obvious in the case of young and parents than elsewhere. I -have had no chance to observe such cases. We should expect -closely associated animals, such as members of a common -troop or animals on friendly terms, to manifest it more -than others. Unfortunately, two of my monkeys, by the -time I was ready to make definite experiments, were on terms -of war. The other had then become so shy that I could not -confidently infer inability to do a thing from actual failure -to do it. He showed no evidence of learning from his -mates. I have, therefore, little evidence of a quantitative -objective nature to present and shall have in the end to ask -the reader to take some opinions without verifiable proofs.</p> - -<p>My reliable experiments, five in number, were of the following -nature. A monkey who had failed of himself (and -often also after a chance to learn from me or from being put<span class="pagenum"><a id="Page_220"></a>[220]</span> -through the act) would be put where he could see another -do the act and get a reward (food) for it. He would then be -given a chance to do it himself, and note would be taken of -his success or failure, and of whether his act was the same -as that of his model in case he succeeded, and of whether he -tried that act more than before the tuition in case he tried -it and failed. The results are given in Table 11.</p> - -<p>In the fourth experiment No. 1 showed further that the -tuition did not cause his successes in that after some successes -further tuition did not improve him.</p> - -<p>There is clearly no evidence here of any imitation of No. 1 -by No. 3. There was also apparently nothing like purposive -watching on the part of No. 3. He seemed often to see No. -1 open the box or work the chute mechanism, but without -special interest.</p> - -<p>This lack of any special curiosity about the doings of their -own species characterized the general behavior of all three of -my monkeys and in itself lessens the probability that they -learn much from one another. Nor did there appear, in the -course of the three months and more the animals were together, -any signs of imitation. There were indeed certain -notable instances of the lack of it in circumstances which -one would suppose would be favorable cases for it.</p> - -<p>For instance: No. 2 was very timid. No. 1 was perfectly -tame from the first day No. 2 was with me, and No. 3 became -tame shortly after. No. 2 saw Nos. 1 and 3 come to me, -be played with, fed and put through experiments, yet he -never did the same nor did he abate a jot or tittle from his -timidity save in so far as I sedulously rewarded any chance -advances of his. Conversely No. 1 and No. 3 seemed uninfluenced -by the fear and shyness of No. 2. No. 2’s cage -was between No. 1’s and No. 3’s, and they were for three -weeks incessantly making hostile demonstrations toward -each other, jumping, chattering, scowling, etc. No. 2 -never did anything of the sort. Again, seeing No. 3 eat -meat did not lead No. 1 to take it; nor did seeing No. 1 -retreat in fright from a bit of absorbent cotton lead No. 3 -to avoid it.</p> - -<p><span class="pagenum"><a id="Page_221"></a>[221]</span></p> - -<h5><span class="smcap">Table 11</span></h5> - -<table class="borders max60"> - <tr> - <th><span class="smcap">Subject, Date, Act</span></th> - <th><span class="smcap">Time tried alone, with result</span></th> - <th><span class="smcap">No. of times imitatee did</span></th> - <th><span class="smcap">Result after chance for imitation</span></th> - <th><span class="smcap">Similarity or dissimilarity of act</span></th> - <th><span class="smcap">Similar act attempted, though unsuccessfully in - cases where it had not been before training</span></th> - <th><span class="smcap">General judgment as to influence of training</span></th> - </tr> - <tr> - <td>No. 3. Dec. 17, 1900. VV (wire loop)</td> - <td class="tdr">50 F</td> - <td class="tdr">43</td> - <td class="tdr">55 F</td> - <td></td> - <td>No.</td> - <td>None.</td> - </tr> - <tr> - <td class="nw">No. 3. Jan. 15, 1901. QQ (c) (nail chute)</td> - <td class="tdr">91 F</td> - <td class="tdr">75</td> - <td class="tdr">35 F</td> - <td></td> - <td>No.</td> - <td>None.</td> - </tr> - <tr> - <td></td> - <td class="tdr">1.30</td> - <td class="tdr"></td> - <td class="tdr"></td> - <td></td> - <td></td> - <td></td> - </tr> - <tr> - <td>No. 3. Jan. 21, 1901. Gamma (wind)</td> - <td class="tdr">63 F</td> - <td class="tdr">43</td> - <td class="tdr">5 F</td> - <td>Dissimilar.</td> - <td>No.</td> - <td>None.</td> - </tr> - <tr> - <td></td> - <td class="tdr"></td> - <td class="tdr"></td> - <td class="tdr">9.00</td> - <td></td> - <td></td> - <td></td> - </tr> - <tr> - <td></td> - <td class="tdr"></td> - <td class="tdr"></td> - <td class="tdr">6.00</td> - <td></td> - <td></td> - <td></td> - </tr> - <tr> - <td>No. 3. Jan. 21, 1901. QQ (ff) (string chute with wire)</td> - <td class="tdr">20 F</td> - <td class="tdr">30</td> - <td class="tdr">1.30</td> - <td>Dissimilar.</td> - <td>No.</td> - <td>None.</td> - </tr> - <tr> - <td></td> - <td class="tdr">2.00</td> - <td class="tdr"></td> - <td class="tdr">.40</td> - <td></td> - <td></td> - <td></td> - </tr> - <tr> - <td></td> - <td class="tdr"></td> - <td class="tdr"></td> - <td class="tdr">.35</td> - <td></td> - <td></td> - <td></td> - </tr> - <tr> - <td></td> - <td class="tdr"></td> - <td class="tdr"></td> - <td class="tdr">5 F</td> - <td></td> - <td></td> - <td></td> - </tr> - <tr> - <td>No. 3. Jan. 23, 1901. QQ (chute)</td> - <td class="tdr">1.15 F</td> - <td class="tdr">40</td> - <td class="tdr">10 F</td> - <td></td> - <td>No.</td> - <td>None.</td> - </tr> -</table> - -<p><span class="pagenum"><a id="Page_222"></a>[222]</span></p> - -<p>Nothing in my experience with these animals, then, favors -the hypothesis that they have any general ability to learn to -do things from seeing others do them. The question is still -an open one, however, and a much more extensive study of it -should be made, especially of the possible influence of imitation -in the case of acts already familiar either as wholes or -in their elements.</p> - -<h4><span class="smcap">Learning apart from Motor Impulses</span></h4> - -<p>The reader of my monograph, ‘Animal Intelligence,’ will -recall that the experiments there reported seemed to show -that the chicks, cats and dogs had only slight and sporadic, -if any, ability to form associations except such as contained -some actual motor impulse. They failed to form such associations -between the sense-impressions and ideas of movements -as would lead them to make the movements without -having themselves previously in those situations given -the motor impulses to the movements. They could not, -for instance, learn to do a thing from having been put -through it by me.</p> - -<p>The monkeys Nos. 1 and 3 were tested in a similar way -with a number of different acts. The general conclusion -from the experiments, the details of which will be given -presently, is that the monkeys are not proved to have the -power of forming associations of ideas to any greater extent -than the other mammals, that they do not demonstrably -learn to do things from seeing or feeling themselves make<span class="pagenum"><a id="Page_223"></a>[223]</span> -the movement. An adult human being whose hand was -taken and made to push in a bar or pull back a bolt would -thereby learn to do it for himself. Cats and dogs would -not, and the monkeys are not proved to do so. On the -other hand, it is impossible for me to say, as of the dogs and -cats, that the monkeys are proved not to do so. In a few -cases the animals did perform acts after having been put -through them which they had failed to perform when left -to their own trial and success method. In the majority of -cases they did not. And in some of these latter cases failure -seemed so improbable in case the animal really had the -power of getting an idea of the act and proceeding from idea -to execution, that one is inevitably led to some explanation -for the few successes other than the presence of ‘ideas.’</p> - -<p>The general manner of making these experiments was like -that in the case of the cats and dogs, save that the monkey’s -paw was used to open the box from the outside instead of -from the inside, and that the monkeys were also put through -the acts necessary to operate some of the chute mechanisms. -Tests parallel to that of comparing the behavior of kittens -who had themselves gone into boxes with those who were -dropped in by me were made in the following manner. I -would carry a monkey from his cage and put him in some -conspicuous place (<i>e.g.</i> on the top of a chair) and then give -him a bit of food. This I would repeat a number of times. -Then I would turn him loose in the room to see whether he -had acquired an idea of being on the chair which would lead -him to himself go to the chair. I would, in order to tell -whether his act, in case he did so, was the result of random -activities or was really due to his tuition, leave him alone for -5 or 10 minutes before the tuition. If he got on the chair -afterwards when he had not before, or got on it much -sooner, it would tend to show that the idea of getting food<span class="pagenum"><a id="Page_224"></a>[224]</span> -on that chair was present and effective. We may call these -last the ‘on chair’ type of experiments.</p> - -<p>A sample experiment with a box is the following:—</p> - -<p>On January 4, 1901, box Delta (push back) was put in No. -1’s cage. He failed in 5, though he was active in trying to -get in for about 4 minutes of the time and pulled and pushed -the bar a great deal, though up and down and out instead of -back. In his aimless pushings and pullings he nearly succeeded. -He failed in 5 in a second trial also. I then opened -the door of the cage, sat down beside it, held out my hand, -and when he came to me took his right paw and with it (he -being held in front of the box) pushed the bar back (and -pulled the door open in those cases when it did not fall open -of itself). He reached in and took the food and went back -to the top of his cage and ate it. (No. 1 generally did this, -while No. 3 generally stayed by me.) I then tried him alone; -result 10 F; no activity at all. On January 5th I put the -box in; result 10 F. He was fairly active. He pulled at -the bar but mostly from a position on the top of the box -and with his left hand; no attempts like the one I had tried -to teach him. Being left alone he failed in 5. Being tried -again with the door of the cage open and me sitting as I had -done while putting him through the act, he succeeded in 7.00 -by pushing the bar with his head in the course of efforts to -poke his head in at the door. I then put him through the -act 10 times and left him to himself. He failed in 5.00; -no activity. I then sat down by the cage as when teaching -him. He failed in 5; little activity. Later in the day I put -him through the act 10 times and then left him to himself. -He failed in 5; little activity. I sat down as before. He -failed in five; little activity. On January 6th I put him -through the act 10 times and then left him. He failed in -10. This was repeated later in the day with the same result.<span class="pagenum"><a id="Page_225"></a>[225]</span> -Record:—By himself, 10 F. Put through 80 times. F 65 -(a) [the (a) refers to a note of his unrepeated chance success -with his head]. No similar act unsuccessfully attempted. -Influence of tuition, none.</p> - -<p>With the chute mechanisms the record would be of the -same nature. With them I put the animal through generally -by taking his paw, held out through the wire netting of -the cage, and making the movement with it. In one experiment -(No. 3 with QQ chute) the first 58 trials were made -by taking the monkey outside the cage and holding him instead -of having him put his paw through the netting for me -to take.</p> - -<p>Many of the experiments were with mechanisms which -had previously been used in experiments concerning the -ability to learn from seeing me operate them. And the -following Table (12) includes the results of experiments of -both sorts. The results of experiments of the ‘on chair’ -type are in Table 13. In cases where the same apparatus -was used for both purposes, the sort of training which was -given first is that where an A is placed.</p> - -<p>In the first four experiments with No. 1 there was some -struggling and agitation on his part while being held and put -through the act. After that there was none in his case except -occasional playfulness, and there was never any with -No. 3 after the first third of the first experiment. The -monkeys soon formed the habit of keeping still, because it -was only when still that I put them through the act and that -food resulted. After you once get them so that they can -be held and their arms taken without their clinging to you, -they quickly learn to adapt themselves to the experiments.</p> - -<p>With No. 1, out of 8 cases where he had of himself failed -(in five of the cases he had also failed after being shown by -me), he succeeded after being put through (13, 21, 51, 10, 7, -80, and 10 times) in two cases (QQ (chute) and RR (wood -plug). The act was unlike the one taught him in the former -case.</p> - -<p><span class="pagenum"><a id="Page_226"></a>[226]</span></p> - -<h5><span class="smcap">Table 12</span></h5> - -<table class="borders max60"> - <tr> - <th><span class="smcap">Subject. Date. Act</span></th> - <th><span class="smcap">Times tried alone, with result</span></th> - <th><span class="smcap">Number of times attention attracted</span></th> - <th><span class="smcap">Result</span></th> - <th><span class="smcap">Number of times shown by me</span></th> - <th><span class="smcap">Result in trials after being shown by me</span></th> - <th><span class="smcap">Number of times put through the act</span></th> - <th><span class="smcap">Result in trials after being put through the act</span></th> - <th><span class="smcap">Comparison of act used with act taught</span></th> - <th><span class="smcap">Similar act attempted though unsuccessfully</span></th> - <th><span class="smcap">Act done once or more, but not repeated in spite of repeated tuition</span></th> - </tr> - <tr class="new"> - <td rowspan="2" class="br">No. 1, Jan. 7, 1900, PP (string across)</td> - <td>10 F</td> - <td></td> - <td></td> - <td></td> - <td></td> - <td>13</td> - <td>10 F</td> - <td></td> - <td>No.</td> - <td></td> - </tr> - <tr> - <td>10 F</td> - <td></td> - <td></td> - <td></td> - <td></td> - <td></td> - <td></td> - <td></td> - <td></td> - <td></td> - </tr> - <tr class="new"> - <td rowspan="2" class="br">No. 1, Jan. 17, 1900, MM (bolt at top)</td> - <td>15 F</td> - <td></td> - <td></td> - <td>21 A</td> - <td>150 F</td> - <td>21</td> - <td>10 F</td> - <td></td> - <td>(?)</td> - <td></td> - </tr> - <tr> - <td></td> - <td></td> - <td></td> - <td></td> - <td>10 F</td> - <td></td> - <td></td> - <td></td> - <td></td> - <td></td> - </tr> - <tr class="new"> - <td rowspan="4" class="br">No. 1, Feb. 24, 1900, OOO (upper string)</td> - <td>2.20</td> - <td></td> - <td></td> - <td>4}</td> - <td>10 F</td> - <td></td> - <td></td> - <td>Partly similar.</td> - <td></td> - <td></td> - </tr> - <tr> - <td>3 F</td> - <td></td> - <td></td> - <td>4} 12</td> - <td>.20</td> - <td></td> - <td></td> - <td></td> - <td>No.</td> - <td></td> - </tr> - <tr> - <td></td> - <td></td> - <td></td> - <td>4}</td> - <td></td> - <td></td> - <td></td> - <td></td> - <td></td> - <td></td> - </tr> - <tr> - <td></td> - <td></td> - <td></td> - <td>4</td> - <td>.22</td> - <td></td> - <td></td> - <td></td> - <td></td> - <td></td> - </tr> - <tr class="new"> - <td>No. 1, Mar. 24, 1900, QQ (chute)</td> - <td>120 F</td> - <td></td> - <td></td> - <td>10 A</td> - <td>60 F</td> - <td>10</td> - <td>30.00</td> - <td>Dissimilar.</td> - <td>No.</td> - <td></td> - </tr> - <tr class="new"> - <td rowspan="4" class="br">No. 1, Apr. 5, 1900, RR (wood plug)</td> - <td>10 F</td> - <td>2</td> - <td>5 F</td> - <td>1 A</td> - <td>2 F</td> - <td>7</td> - <td>2.20</td> - <td>Similar.</td> - <td>Yes(?)</td> - <td></td> - </tr> - <tr> - <td></td> - <td></td> - <td></td> - <td>1</td> - <td>2 F</td> - <td>2</td> - <td>2.00</td> - <td></td> - <td></td> - <td></td> - </tr> - <tr> - <td></td> - <td></td> - <td></td> - <td>1</td> - <td>2 F</td> - <td></td> - <td></td> - <td></td> - <td></td> - <td></td> - </tr> - <tr> - <td></td> - <td></td> - <td></td> - <td>1</td> - <td>5 F</td> - <td></td> - <td></td> - <td></td> - <td></td> - <td></td> - </tr> - <tr class="new"> - <td rowspan="4" class="br">No. 1, Oct. 20, 1900, VV (loop)</td> - <td>10 F</td> - <td></td> - <td></td> - <td>4</td> - <td>.22</td> - <td></td> - <td></td> - <td>Similar.</td> - <td></td> - <td></td> - </tr> - <tr> - <td>10 F</td> - <td></td> - <td></td> - <td></td> - <td></td> - <td></td> - <td></td> - <td></td> - <td></td> - <td></td> - </tr> - <tr> - <td>10 F</td> - <td></td> - <td></td> - <td></td> - <td></td> - <td></td> - <td></td> - <td></td> - <td></td> - <td></td> - </tr> - <tr> - <td>10 F</td> - <td></td> - <td></td> - <td></td> - <td></td> - <td></td> - <td></td> - <td></td> - <td></td> - <td></td> - </tr> - <tr class="new"> - <td>No. 1, Nov. 19, 1900, Theta (new bolt)</td> - <td>10 F</td> - <td></td> - <td></td> - <td>5</td> - <td>10 F</td> - <td>51 A</td> - <td>132 F</td> - <td></td> - <td>No.</td> - <td></td> - </tr> - <tr class="new"> - <td rowspan="2" class="br">No. 1, Jan. 4, 1901, Delta (push back)</td> - <td>10 F</td> - <td></td> - <td></td> - <td>15</td> - <td>10 F</td> - <td>80 A</td> - <td>65 F<a id="FNanchor_31" href="#Footnote_31" class="fnanchor">[31]</a></td> - <td></td> - <td>No.</td> - <td><span class="pagenum"><a id="Page_227"></a>[227]</span></td> - </tr> - <tr> - <td></td> - <td></td> - <td></td> - <td></td> - <td></td> - <td></td> - <td></td> - <td></td> - <td></td> - <td></td> - </tr> - <tr class="new"> - <td rowspan="3" class="br">No. 1, Jan. 6, 1901, QQ (a) (single wind chute)</td> - <td>8.00</td> - <td></td> - <td></td> - <td>40</td> - <td>10 F</td> - <td></td> - <td></td> - <td>Dissimilar.</td> - <td></td> - <td></td> - </tr> - <tr> - <td></td> - <td></td> - <td></td> - <td></td> - <td>2.00</td> - <td></td> - <td></td> - <td></td> - <td></td> - <td></td> - </tr> - <tr> - <td></td> - <td></td> - <td></td> - <td></td> - <td>.50</td> - <td></td> - <td></td> - <td></td> - <td></td> - <td></td> - </tr> - <tr class="new"> - <td rowspan="3" class="br">No. 1, Jan. 7, 1901, Zeta (side plug new)</td> - <td>5 F</td> - <td></td> - <td></td> - <td></td> - <td></td> - <td></td> - <td></td> - <td></td> - <td></td> - <td></td> - </tr> - <tr> - <td></td> - <td></td> - <td></td> - <td></td> - <td></td> - <td>20</td> - <td>im.</td> - <td>?</td> - <td></td> - <td></td> - </tr> - <tr> - <td>1.10</td> - <td></td> - <td></td> - <td></td> - <td></td> - <td></td> - <td>im.</td> - <td></td> - <td></td> - <td></td> - </tr> - <tr class="new"> - <td rowspan="4" class="br">No. 1, Jan. 9, 1901, QQ (b) (2½ wind chute)</td> - <td>3.00 to .06</td> - <td></td> - <td></td> - <td>10</td> - <td>5 F</td> - <td></td> - <td></td> - <td>Dissimilar.</td> - <td>No.</td> - <td>Yes.</td> - </tr> - <tr> - <td></td> - <td></td> - <td></td> - <td></td> - <td>5 F</td> - <td></td> - <td></td> - <td></td> - <td></td> - <td></td> - </tr> - <tr> - <td>5 F</td> - <td></td> - <td></td> - <td></td> - <td>3.00</td> - <td></td> - <td></td> - <td></td> - <td></td> - <td></td> - </tr> - <tr> - <td></td> - <td></td> - <td></td> - <td></td> - <td>5 F</td> - <td></td> - <td></td> - <td></td> - <td></td> - <td></td> - </tr> - <tr class="new"> - <td rowspan="2" class="br">No. 1, Jan. 11, 1901, QQ (c) (nail chute)</td> - <td>5 F</td> - <td>5</td> - <td>5 F</td> - <td>1<a id="FNanchor_32" href="#Footnote_32" class="fnanchor">[32]</a></td> - <td>2.20</td> - <td></td> - <td></td> - <td>Dissimilar.</td> - <td></td> - <td>Yes.<a id="FNanchor_33" href="#Footnote_33" class="fnanchor">[33]</a></td> - </tr> - <tr> - <td>5 F</td> - <td></td> - <td></td> - <td></td> - <td></td> - <td></td> - <td></td> - <td></td> - <td></td> - <td></td> - </tr> - <tr class="new"> - <td rowspan="3" class="br">No. 1, Jan. 12, 1901, Epsilon (push down)</td> - <td>5 F</td> - <td></td> - <td></td> - <td>25 A</td> - <td>10 F</td> - <td>10</td> - <td>5 F</td> - <td></td> - <td>No.</td> - <td></td> - </tr> - <tr> - <td>10 F</td> - <td></td> - <td></td> - <td></td> - <td>10 F</td> - <td>10</td> - <td>10 F</td> - <td></td> - <td></td> - <td></td> - </tr> - <tr> - <td></td> - <td></td> - <td></td> - <td>15</td> - <td>10 F</td> - <td></td> - <td></td> - <td></td> - <td></td> - <td></td> - </tr> - <tr class="new"> - <td rowspan="2" class="br">No. 1, Jan. 16, 1901, QQ (d) (pull chute)</td> - <td>5 F</td> - <td>5</td> - <td>3.30</td> - <td></td> - <td></td> - <td></td> - <td></td> - <td></td> - <td></td> - <td></td> - </tr> - <tr> - <td>5 F</td> - <td></td> - <td>.10</td> - <td></td> - <td></td> - <td></td> - <td></td> - <td></td> - <td></td> - <td></td> - </tr> - <tr class="new"> - <td rowspan="2" class="br">No. 1, Jan. 17, 1901, QQ (f) (string chute)</td> - <td>5 F</td> - <td>5</td> - <td>5 F</td> - <td>15 A</td> - <td>5 F</td> - <td>10</td> - <td>5 F</td> - <td></td> - <td></td> - <td></td> - </tr> - <tr> - <td></td> - <td></td> - <td></td> - <td></td> - <td>5 F</td> - <td></td> - <td></td> - <td></td> - <td></td> - <td></td> - </tr> - <tr class="new"> - <td rowspan="2" class="br">No. 1, Jan. 18, 1901, QQ (e) (hook chute)</td> - <td>5 F</td> - <td>3</td> - <td>im.</td> - <td></td> - <td></td> - <td></td> - <td></td> - <td></td> - <td></td> - <td><span class="pagenum"><a id="Page_228"></a>[228]</span></td> - </tr> - <tr> - <td></td> - <td></td> - <td></td> - <td></td> - <td></td> - <td></td> - <td></td> - <td></td> - <td></td> - <td></td> - </tr> - <tr class="new"> - <td rowspan="2" class="br">No. 3, Dec. 17, 1900, QQ (chute)</td> - <td>60 F</td> - <td>3</td> - <td>60 F</td> - <td>10 A</td> - <td>5 F</td> - <td>113</td> - <td>90 F</td> - <td></td> - <td>(?)</td> - <td></td> - </tr> - <tr> - <td></td> - <td></td> - <td></td> - <td>30</td> - <td>30 F</td> - <td></td> - <td></td> - <td></td> - <td></td> - <td></td> - </tr> - <tr class="new"> - <td rowspan="2" class="br">No. 3, Dec. 17, 1900, VV (loop)</td> - <td>10 F</td> - <td></td> - <td></td> - <td></td> - <td></td> - <td>23</td> - <td>20 F</td> - <td></td> - <td>No.</td> - <td></td> - </tr> - <tr> - <td>20 F</td> - <td></td> - <td></td> - <td></td> - <td></td> - <td></td> - <td></td> - <td></td> - <td></td> - <td></td> - </tr> - <tr class="new"> - <td rowspan="4" class="br">No. 3, Jan. 4, 1901, Delta (push back)</td> - <td>10 F</td> - <td></td> - <td></td> - <td>20</td> - <td>8.00<a id="FNanchor_34" href="#Footnote_34" class="fnanchor">[34]</a></td> - <td>5 A</td> - <td>2.00<a id="FNanchor_35" href="#Footnote_35" class="fnanchor">[35]</a></td> - <td>Dissimilar.</td> - <td>No.</td> - <td></td> - </tr> - <tr> - <td>2.10 (by pulling string)</td> - <td></td> - <td></td> - <td></td> - <td>8.00<a href="#Footnote_34" class="fnanchor">[34]</a></td> - <td>5</td> - <td>3.20</td> - <td></td> - <td></td> - <td></td> - </tr> - <tr> - <td></td> - <td></td> - <td></td> - <td></td> - <td></td> - <td>15</td> - <td>30 F</td> - <td></td> - <td></td> - <td></td> - </tr> - <tr> - <td></td> - <td></td> - <td></td> - <td></td> - <td></td> - <td>5</td> - <td>10 F</td> - <td></td> - <td></td> - <td></td> - </tr> - <tr class="new"> - <td rowspan="2" class="br">No. 3, Jan. 4, 1901, Gamma (wind)</td> - <td>10 F</td> - <td></td> - <td></td> - <td>30</td> - <td>10 F</td> - <td>20 A</td> - <td>5 F</td> - <td></td> - <td>No.</td> - <td></td> - </tr> - <tr> - <td>10 F</td> - <td></td> - <td></td> - <td></td> - <td>10 F</td> - <td></td> - <td>8 F</td> - <td></td> - <td></td> - <td></td> - </tr> - <tr class="new"> - <td>No. 3, Jan. 8, 1901, Theta (bolt at top)</td> - <td>10 F<a id="FNanchor_36" href="#Footnote_36" class="fnanchor">[36]</a></td> - <td></td> - <td></td> - <td>25</td> - <td>6 F</td> - <td></td> - <td></td> - <td>Dissimilar.</td> - <td></td> - <td></td> - </tr> - <tr class="new"> - <td rowspan="4" class="br">No. 3, Jan. 9, 1901, QQ (a) (chute bar)</td> - <td>10 F</td> - <td></td> - <td></td> - <td></td> - <td>3.00<a id="FNanchor_37" href="#Footnote_37" class="fnanchor">[37]</a></td> - <td>10</td> - <td></td> - <td></td> - <td>No complete circle.</td> - <td></td> - </tr> - <tr> - <td></td> - <td></td> - <td></td> - <td></td> - <td></td> - <td>10</td> - <td>.40</td> - <td>?</td> - <td></td> - <td></td> - </tr> - <tr> - <td></td> - <td></td> - <td></td> - <td></td> - <td></td> - <td>10</td> - <td>1.00</td> - <td></td> - <td></td> - <td></td> - </tr> - <tr> - <td></td> - <td></td> - <td></td> - <td></td> - <td></td> - <td>10</td> - <td>1.00</td> - <td></td> - <td></td> - <td></td> - </tr> - <tr class="new"> - <td rowspan="3" class="br">No. 3, Jan. 9, 1901, QQ (b) (2½ wind chute)</td> - <td>10 F</td> - <td></td> - <td></td> - <td>20</td> - <td>8 F</td> - <td></td> - <td>5 F</td> - <td>Dissimilar.</td> - <td></td> - <td>Yes.</td> - </tr> - <tr> - <td><span class="pagenum"><a id="Page_229"></a>[229]</span></td> - <td></td> - <td></td> - <td></td> - <td>8 F</td> - <td></td> - <td></td> - <td></td> - <td></td> - <td></td> - </tr> - <tr> - <td></td> - <td></td> - <td></td> - <td></td> - <td></td> - <td></td> - <td></td> - <td></td> - <td></td> - <td></td> - </tr> - <tr class="new"> - <td rowspan="5" class="br">No. 3, Jan. 11, 1901, QQ (c) (nail chute)</td> - <td>5 F</td> - <td>10</td> - <td>5 F</td> - <td>25 A</td> - <td>5 F</td> - <td>45</td> - <td>38 F</td> - <td></td> - <td>No.</td> - <td>Yes.</td> - </tr> - <tr> - <td>5 F</td> - <td></td> - <td>12 F<a id="FNanchor_38" href="#Footnote_38" class="fnanchor">[38]</a></td> - <td></td> - <td>5 F</td> - <td></td> - <td></td> - <td></td> - <td></td> - <td></td> - </tr> - <tr> - <td></td> - <td></td> - <td></td> - <td></td> - <td>1.30</td> - <td>10</td> - <td>10 F</td> - <td></td> - <td></td> - <td></td> - </tr> - <tr> - <td></td> - <td></td> - <td></td> - <td></td> - <td>5 F</td> - <td></td> - <td></td> - <td></td> - <td></td> - <td></td> - </tr> - <tr> - <td></td> - <td></td> - <td></td> - <td></td> - <td>10 F</td> - <td></td> - <td></td> - <td></td> - <td></td> - <td></td> - </tr> - <tr class="new"> - <td rowspan="3" class="br">No. 3, Jan. 15, 1901, Epsilon (push down)</td> - <td>10 F</td> - <td></td> - <td></td> - <td>25 A</td> - <td>5 F</td> - <td>20</td> - <td>11.00</td> - <td></td> - <td>No.</td> - <td>Yes.</td> - </tr> - <tr> - <td></td> - <td></td> - <td></td> - <td></td> - <td>5 F</td> - <td></td> - <td>30 F</td> - <td>?</td> - <td></td> - <td></td> - </tr> - <tr> - <td></td> - <td></td> - <td></td> - <td></td> - <td></td> - <td>15</td> - <td>10 F</td> - <td></td> - <td></td> - <td></td> - </tr> - <tr class="new"> - <td rowspan="3" class="br">No. 3, Jan. 16, 1901, QQ (e) (hook chute)</td> - <td>5 F</td> - <td>5</td> - <td>5 F</td> - <td>5 A</td> - <td>2.00</td> - <td>10</td> - <td>.10</td> - <td>Dissimilar.</td> - <td>No.</td> - <td></td> - </tr> - <tr> - <td></td> - <td></td> - <td></td> - <td></td> - <td>1.25</td> - <td></td> - <td>.10</td> - <td></td> - <td></td> - <td></td> - </tr> - <tr> - <td></td> - <td></td> - <td></td> - <td></td> - <td>1.20</td> - <td></td> - <td></td> - <td></td> - <td></td> - <td></td> - </tr> - <tr class="new"> - <td rowspan="4" class="br">No. 3, Jan. 19, 1901, QQ (ff) (string chute with wire)</td> - <td>5 F</td> - <td></td> - <td>5</td> - <td>5 A</td> - <td>5 F</td> - <td>7</td> - <td>5 F</td> - <td></td> - <td></td> - <td></td> - </tr> - <tr> - <td>5 F</td> - <td></td> - <td></td> - <td></td> - <td></td> - <td>8</td> - <td>5 F</td> - <td></td> - <td></td> - <td></td> - </tr> - <tr> - <td>2.00<a id="FNanchor_39" href="#Footnote_39" class="fnanchor">[39]</a></td> - <td></td> - <td></td> - <td></td> - <td></td> - <td>12</td> - <td>3.00</td> - <td>Dissimilar.</td> - <td>No.</td> - <td></td> - </tr> - <tr> - <td></td> - <td></td> - <td></td> - <td></td> - <td></td> - <td></td> - <td>5 F</td> - <td></td> - <td></td> - <td></td> - </tr> - <tr class="new"> - <td rowspan="3" class="br">No. 3, Jan. 22, 1901, WW (bar inside)</td> - <td>5 F previously some 40.00 F</td> - <td></td> - <td></td> - <td></td> - <td></td> - <td>10</td> - <td>5 F</td> - <td></td> - <td></td> - <td></td> - </tr> - <tr> - <td></td> - <td></td> - <td></td> - <td></td> - <td></td> - <td></td> - <td>6.00<a id="FNanchor_40" href="#Footnote_40" class="fnanchor">[40]</a></td> - <td></td> - <td></td> - <td></td> - </tr> - <tr> - <td></td> - <td></td> - <td></td> - <td></td> - <td></td> - <td></td> - <td>7.00<a href="#Footnote_40" class="fnanchor">[40]</a></td> - <td>Dissimilar.</td> - <td>No.</td> - <td></td> - </tr> -</table> - -<p><span class="pagenum"><a id="Page_230"></a>[230]</span></p> - -<p>In only one case (bolt at top) out of eight was there possibly -any attempt at the act after he had been put through -which had not been made before. The ‘yes or?’ in the -table with RR was a case occurring after the imitation of me -but before the putting No. 1 through.</p> - -<p>Out of 6 cases where he had himself failed, No. 3 succeeded -(after being put through 113, 23, 20, 10, 10, 20 and 10 -times) in 3 cases (chute bar, push down and bar inside). -The act was dissimilar in all three cases, bearing absolutely -no resemblance in one case. There was no unsuccessful -attempt at the act taught him in any of the cases. With -the chute he did finger the bar after tuition where he had -not done so before, but it was probably an accidental result -of his holding his hand out toward it for me to take as he had -formed the habit of doing. In the case of box Epsilon -(push down), with which he succeeded by pushing his hand -in above the lever (an act which though unlike that taught -him might be by some considered to be due to an idea -gained from the tuition), he failed entirely after further -tuition (15 times).</p> - -<p>Like the dogs and cats, then, the monkeys seemed unable -to learn to do things from being put through them. We -may now examine those which they did do of themselves before -tuition and ask whether they learned the more rapidly -thereby or modified their behavior in ways which might be -due to the tuition. There are too few cases and no chance -for comparison on the first point; on the second the records -are unanimous in showing no change in the method of operating -the mechanisms due to the tuition.</p> - -<p>As in Table 9, figures followed by F mean that in that<span class="pagenum"><a id="Page_231"></a>[231]</span> -length of time the animal failed. Figures without an F denote -the time taken by the animal to operate the mechanism.</p> - -<p>As a supplement to Table 12 I have made a summary of -the cases where the animals did succeed after tuition, that -shows the nature of the act shown them as compared with -the act they made use of.</p> - -<h5><span class="smcap">Supplement to Table 12</span></h5> - -<table class="borders align-top"> - <tr> - <th><span class="smcap">Apparatus</span></th> - <th><span class="smcap">Model given or act put through</span></th> - <th><span class="smcap">Act of No. 1</span></th> - <th><span class="smcap">Act of No. 3</span></th> - </tr> - <tr> - <td>OOO</td> - <td>To pull upper string.</td> - <td>Pulled both strings alternately, but upper enough more to succeed.</td> - <td></td> - </tr> - <tr> - <td>QQ</td> - <td>To push bar in.</td> - <td>Inserted fingers between bar and its slot and pulled and pushed vaguely.</td> - <td></td> - </tr> - <tr> - <td>RR</td> - <td>To pull plug out with right hand.</td> - <td>Pulled and bit.</td> - <td></td> - </tr> - <tr> - <td>VV</td> - <td>To pull loop off nail with right hand.</td> - <td><i>Similar.</i></td> - <td></td> - </tr> - <tr> - <td>QQ (a)</td> - <td>To pull bar around toward him.</td> - <td>Pulled back and forth indiscriminately.</td> - <td>Pulled back and forth indiscriminately.</td> - </tr> - <tr> - <td>QQ (b)</td> - <td>To pull bar around toward him in 2½ continuous revolutions.</td> - <td>Pulled back and forth indiscriminately.</td> - <td></td> - </tr> - <tr> - <td>QQ (c)</td> - <td>To take nail and pull directly outward.</td> - <td>Pulled back and forth.</td> - <td><i>Similar</i> or nearly so.</td> - </tr> - <tr> - <td>Delta</td> - <td>To push bar to right with right hand.</td> - <td></td> - <td>Did before tuition by pulling wire; after tuition by chance movement of head.</td> - </tr> - <tr> - <td>Theta</td> - <td>To pull bolt up with right hand.</td> - <td></td> - <td>Pulled door and worked bolt loose.</td> - </tr> - <tr> - <td><span class="pagenum"><a id="Page_232"></a>[232]</span>Epsilon</td> - <td>To stand in front, insert fingers of right hand and press lever down.</td> - <td></td> - <td>Inserted arm in general activity while on top of the box.</td> - </tr> - <tr> - <td>QQ (e)</td> - <td>To pull hook down.</td> - <td></td> - <td>Pulled at the lever and hook in a general attack on the apparatus.</td> - </tr> - <tr> - <td>QQ (ff)</td> - <td>To pull wire loop off nail with right hand.</td> - <td></td> - <td>Pulled outward on the lever which pushed the banana down the chute so hard as to pull it off its pivot.</td> - </tr> - <tr> - <td>WW</td> - <td>To stand on top of box, reach right hand down and pull bar up.</td> - <td></td> - <td>Pulled at door until bar worked out of its catch.</td> - </tr> -</table> - -<p>I have kept the results of the tests of the ‘on chair’ type -separate from the others because they may be tests of a different -thing and surely are subject to different conditions.</p> - -<p>They were tests of the animals’ ability to form the habit of -going to a certain place by reason of having been <i>carried</i> -there and securing food thereby. I would leave the animal -loose in the room, and if he failed in 5 or 10 minutes to go to -the place of his own accord, would put him back in his cage; -if he did go of his own accord, I would note the time. Then -I would take him, carry him to the place, and feed him. -After doing this 10 times I would turn him loose again and -see whether the idea of being fed in such and such a place was -present and active in making him go to the place. In such -tests we are absolutely sure that the animal can without any -difficulty perform the necessary movements and would in<span class="pagenum"><a id="Page_233"></a>[233]</span> -case the proper stimulus to set them off appeared, if, for -instance, a bit of food on one of the places to which he was to -go caught his eye. In so far forth the tests were favorable -cases for learning. On the other hand, the situation associated -with getting food may have been in these cases not -the mere ‘being on box’ but the whole previous experience -‘being carried while clinging and being put or let jump on a -box.’ In this respect the tests may have been less favorable -than the acts where getting food was always the direct -sequent of the act of going into the box.</p> - -<p>The experiments were:—</p> - -<p>A. Carrying the animal and putting him on a chair.</p> - -<p>B. Carrying the animal and putting him on a pile of boxes.</p> - -<p>C. Carrying the animal and putting him on the top of a -sewing machine.</p> - -<p>D. Carrying the animal and putting him on the middle of -a board 6 feet long, stretched horizontally across the room, -3 feet from the floor.</p> - -<p>E. Carrying the animal and putting him on the side of the -cage, head down.</p> - -<p>The results are given in Table 13.</p> - -<p>The size of the room in which I worked and other practical -difficulties prevented me from extending these experiments. -As they stand, no stable judgments can be inferred from -them. It should be noted that in the successful cases there -were no other signs of the presence of the idea ‘food when -there’ than the mere going to a certain place. The animal -did not wait at the place more than a second or two, did not -look at me or show any signs of expecting anything.</p> - -<p><span class="pagenum"><a id="Page_234"></a>[234]</span></p> - -<h5><span class="smcap">Table 13</span></h5> - -<table class="borders"> - <tr> - <th><span class="smcap">Experiment and date</span></th> - <th><span class="smcap">Animal</span></th> - <th><span class="smcap">Results before training</span></th> - <th><span class="smcap">Number of times put through</span></th> - <th><span class="smcap">Results after training</span></th> - </tr> - <tr> - <td>A. Jan. 22, 1901</td> - <td>No. 1.</td> - <td>5 F</td> - <td>10</td> - <td>1.00</td> - </tr> - <tr> - <td></td> - <td></td> - <td></td> - <td></td> - <td>3.00</td> - </tr> - <tr> - <td>    Jan. 22, 1901</td> - <td>No. 1.</td> - <td>5 F</td> - <td>10</td> - <td>im.</td> - </tr> - <tr> - <td></td> - <td></td> - <td></td> - <td></td> - <td>3.30</td> - </tr> - <tr> - <td>    Jan. 23, 1901</td> - <td>No. 3.</td> - <td>5 F</td> - <td>10</td> - <td>3.30</td> - </tr> - <tr> - <td></td> - <td></td> - <td>5 F</td> - <td></td> - <td></td> - </tr> - <tr> - <td>B. Jan. 26, 1901</td> - <td>No. 1.</td> - <td>10 F</td> - <td>10 and 5</td> - <td>10 F 5 F</td> - </tr> - <tr> - <td></td> - <td>No. 3.</td> - <td>5 F</td> - <td>10</td> - <td>5 F</td> - </tr> - <tr> - <td></td> - <td></td> - <td></td> - <td>10</td> - <td>5 F</td> - </tr> - <tr> - <td>C. Jan. 27, 1901</td> - <td>No. 1.</td> - <td>5 F</td> - <td>10</td> - <td>3.00</td> - </tr> - <tr> - <td>D. Jan. 27, 1901</td> - <td>No. 1.</td> - <td>3.20</td> - <td>10</td> - <td>5 F</td> - </tr> - <tr> - <td>E. Jan. 26, 1901</td> - <td>No. 3.</td> - <td>5 F</td> - <td>5</td> - <td>5 F</td> - </tr> -</table> - -<p>Although, as I noted in the early part of this monograph, -there were occasionally phenomena in the general behavior -of the monkeys which of themselves impressed one as being -suggestive of an ideational life, the general run of their -learning apart from the specific experiments described was -certainly confined to the association of impulses of their -own with certain situations. The following examples will -suffice:—</p> - -<p>In getting them so that they would let themselves be handled -it was of almost no service to <i>take</i> them and feed them -while holding them or otherwise make that state pleasant -for them. By far the best way is to wait patiently till they -do come near, then feed them; wait patiently till they do -take hold of your arm, then feed them. If you do take them -and hold them partly by force, you must feed them only -when they are comparatively still. In short, in taming -them one comes unconsciously to adopt the method of rewarding -certain of their impulses rather than certain <i>conditions</i> -which might be associated in their minds with ideas, -had they such.</p> - -<p>After No. 1 and No. 3 had both reached a point where -both could hardly be gotten to leave me and go back into<span class="pagenum"><a id="Page_235"></a>[235]</span> -their cages or down to the floor of the room, where they evidently -enjoyed being held by me, they still did not climb -upon me. The idea of clinging to me was either absent or -impotent to cause them to act. What they did do was, in -the case of No. 1, to jump about, pawing around in the -air, until I caught an arm or leg, to which stimulus he had -by dint of the typical sort of animal association learned to -react by jumping to my arm and clinging there; in the case -of No. 3, to stand still until I held my arm right in front of -him (if he were in his cage) or to come and stand on his -hind legs in front of me (if he were out on the floor). In -both cases No. 3’s act was one which had been learned by -my rewarding his impulses. I often tried, at this period of -their intimacy with me, this instructive experiment. The -monkey would be clinging to me so that I could hardly -tear him away. I would do so, and he would, if dropped -loose from me, make no efforts to get back.</p> - -<p>I have already mentioned my failure to get the animals to -put out their right hands through the netting after they had -long done so with their left hands. With No. 3 I tried putting -my fingers through and poking the arm out and then -making the movement with it. He profited little if any by -this tuition. Had I somehow induced him to do it himself, -a few trials would have been sufficient to get the habit well -under way.</p> - -<p>Monkey No. 1 apparently enjoyed scratching himself. -Among the stimuli which served to set off this act of scratching -was the irritation from tobacco smoke. If any one -would blow smoke in No. 1’s face, he would blink his eyes -and scratch himself, principally in the back. After a time -he got in the habit of coming to the front of his cage when -any one was smoking and making such movements and -sounds as in his experience had attracted attention and<span class="pagenum"><a id="Page_236"></a>[236]</span> -caused the smoker to blow in his face. He was often given -a lighted cigar or cigarette to test him for imitation. He -formed the habit of rubbing it on his back. After doing so -he would scratch himself with great vigor and zest. He -came to do this always when the proper object was given -him. I have recounted all this to show that the monkey -enjoyed scratching himself. <i>Yet he apparently never -scratched himself except in response to some sensory stimulus.</i> -He was apparently incapable of thinking ‘scratch’ and so -doing. Yet the act was quite capable of association with -circumstances with which as a matter of hereditary organization -it had no connection. For by taking a certain well-defined -position in front of his cage and feeding him whenever -he did scratch himself I got him to always scratch -within a few seconds after I took that position.</p> - -<h3><span class="smcap">General Mental Development of the Monkeys</span></h3> - -<p>It is to be hoped that the growing recognition of the worth -of comparative and genetic studies will lead to investigations -of the mental make-up of other species of monkeys, and -to the careful overhauling of the work done so far, including -these rather fragmentary studies of mine. Work with three -monkeys of one species, especially when no general body of -phenomena, such as one has at hand in the case of domestic -animals, can be used as a means of comparison, must necessarily -be of limited application in all its details and of insecure -application even in its general features. What I shall -say concerning the advance in the mental development -of the monkeys over that of other mammals may then be -in strictness true of only my three subjects, and it may be -left to the judgment of individuals to extend my conclusions<span class="pagenum"><a id="Page_237"></a>[237]</span> -as far as seems to them likely. To me it seems fairly likely -that the very general mental traits which the research has -demonstrated hold true with little variation in the monkeys -in general.</p> - -<p>The monkeys represent progress in mental development -from the generalized mammalian type toward man:—</p> - -<p>1. In their sensory equipment, in the presence of focalized -vision.</p> - -<p>2. In their motor equipment, in the coördinated movements -of the hand and the eye.</p> - -<p>3. In their instincts or inherited nervous connections, in -their general physical and mental activity.</p> - -<p>4. In their method of learning or associative processes; -in—</p> - -<ul> -<li><i>a.</i> Quicker formation of associations,</li> -<li><i>b.</i> Greater number of associations,</li> -<li><i>c.</i> Greater delicacy of associations,</li> -<li><i>d.</i> Greater complexity of associations,</li> -<li><i>e.</i> Greater permanence of associations.</li> -</ul> - -<p>The fact of (1) is well known to comparative anatomists. -Its importance in mental development is perhaps not realized, -but appears constantly to a systematic student.</p> - -<p>(2) is what accounts for much of the specious appearance -of human ways of thinking in the monkeys and becomes in -its human extension the handy tool for much of our intellectual -life. It is in great measure the prerequisite of 4 <i>c</i>.</p> - -<p>(3) accounts for the rest of such specious appearances, is -at the basis of much of 4 <i>b</i>, presages the similar though -extended instincts of the human being, which I believe are -the leading efficient causes of human mental capacity, and -is thus the great mental bond which would justify the inclusion -of monkeys and man in a common group if we were -to classify animals on the basis of mental characteristics.</p> - -<p><span class="pagenum"><a id="Page_238"></a>[238]</span></p> - -<p>Even the casual observer, if he has any psychological insight, -will be struck by the general, aimless, intrinsically -valuable (to the animal’s feelings) physical activities of a -monkey compared with the specialized, definitely aroused, -utilitarian activities of a dog or cat. Watch the latter and -he does but few things, does them in response to obvious -sense presentations, does them with practical consequences -of food, sex-indulgence, preparation for adult battles, etc. -If nothing that appeals to his special organization comes -up, he does nothing. Watch a monkey and you cannot -enumerate the things he does, cannot discover the stimuli -to which he reacts, cannot conceive the <i>raison d’être</i> of -his pursuits. Everything appeals to him. He likes to be -active for the sake of activity.</p> - -<p>The observer who has proper opportunities and takes -proper pains will find this intrinsic interest to hold of mental -activity as well. No. 1 happened to hit a projecting -wire so as to make it vibrate. He repeated this act hundreds -of times in the few days following. He did not, could -not, eat, make love to, or get preliminary practice for the -serious battles of life out of, that sound. But it did give -him mental food, mental exercise. Monkeys seem to enjoy -strange places; they revel, if I may be permitted an anthropomorphism, -in novel objects. They like to have -feelings as they do to make movements. The fact of mental -life is to them its own reward.</p> - -<p>It is beyond question rash for any one to venture hypotheses -concerning the brain parallel of mental conditions, -most of all for the ignoramus in the comparative histology -of the nervous system, but one cannot help thinking that -the behavior of the monkeys points to a cerebrum that is no -longer a conservative machine for making a few well-defined -sorts of connections between sense-impressions and acts,<span class="pagenum"><a id="Page_239"></a>[239]</span> -that is not only fitted to do more delicate work in parts, -but is also alive, tender all over, functioning throughout, -set off in action by anything and everything. And if one -adds coördinations allowing a freedom and a differentiation -of action of the muscles used in speech comparable to that -already present in connection with the monkey’s hand, he -may well ask, “What more of a nervous mechanism do -you need to parallel the behavior of the year-old child?” -However, this is not the place to speculate upon the importance -to human development of our instinctive aimless -activity, physical and mental, or to describe further its -similarity and evident phylogenetic relationship to the instinctive -behavior of the monkeys. Elsewhere I shall undertake -that task.</p> - -<p>4. In their method of learning, the monkeys do not advance -far beyond the generalized mammalian type, but in -their proficiency in that method they do. They seem at -least to form associations very much faster, and they form -very many more. They also seem superior in the delicacy -and in the complexity of the associations formed and the -connections seem to be more permanent.</p> - -<p>This progress may seem, and doubtless will to the thinker -who looks upon the human intellect as a collection of functions -of which ideation, judgment and reasoning are chief, -to be slight. To my mind it is not so in reality. For it -seems to me highly probable that the so-called ‘higher’ intellectual -processes of human beings are but secondary results -of the general function of having free ideas and that -this general function is the result of the formation after the -fashion of the animals of a very great number of associations. -I should therefore say, “Let us not wonder at the comparative -absence of free ideas in the monkeys, much less at -the absence of inferences or concepts. Let us not wonder<span class="pagenum"><a id="Page_240"></a>[240]</span> -that the only demonstrable intellectual advance of the monkeys -over the mammals in general is the change from a few, -narrowly confined, practical associations to a multitude of -all sorts, for that may turn out to be at the bottom the -only <i>demonstrable advance of man</i>, an advance which in connection -with a brain acting with increased delicacy and -irritability, brings in its train the functions which mark off -human mental faculty from that of all other animals.”</p> - -<p>The typical process of association described in Chapter II -has since been found to exist among reptiles (by Mr. R. -M. Yerkes) and among fishes (by myself). It seems fairly -likely that not much more characterizes the primates. If -such work as that of Lubbock and the Peckhams holds its -own against the critical studies of Bethe, this same process -exists in the insects. Yerkes and Bosworth think they -have demonstrated its presence in the crayfish. Even if -we regard the learning of the invertebrates as problematic, -still this process is the most comprehensive and important -thing in mental life. I have already hinted that we ought -to turn our views of human psychology upside down and -study what is now casually referred to in a chapter on habit -or on the development of the will, as the general psychological -law, of which the commonly named processes are -derivatives. When this is done, we shall not only relieve -human mentality from its isolation and see its real relationships -with other forms; we may also come to know more -about it, may even elevate our psychologies to the explanatory -level and connect mental processes with nervous activities -without arousing a sneer from the logician or a grin -from the neurologist.</p> - -<hr class="chap x-ebookmaker-drop"> - -<div class="chapter"> - -<p><span class="pagenum"><a id="Page_241"></a>[241]</span></p> - -<h2 class="nobreak" id="CHAPTER_VI">CHAPTER VI<br> -<span class="smcap">Laws and Hypotheses for Behavior</span></h2> - -</div> - -<h3><span class="smcap">Laws of Behavior in General</span></h3> - -<p><i>Behavior is predictable.</i> The first law of behavior, one -fraction of the general law of the uniformity of nature, is -that with life and mind, as with mass and motion, the same -cause will produce the same effect,—that <i>the same situation -will, in the same animal, produce the same response</i>,—and -that <i>if the same situation produces on two occasions two -different responses, the animal must have changed</i>.</p> - -<p>Scientific students of behavior will, with few exceptions, -accept this law in theory, but in practice we have not fully -used it. We have too often been content to say that a man -may respond in any one of several ways to the same situation, -or may attend to one rather than another feature of -the same object, without insisting that the man must in each -case be different, and without searching for the differences -in him which cause the different reactions.</p> - -<p>The changes in an organism which make it respond differently -on different occasions to the same situation range from -temporary to permanent changes. Hunger, fatigue, sleep, -and certain diseases on the one hand, and learning, immunity, -growth and senility on the other, illustrate this range.</p> - -<p>Behavior is predictable <i>without recourse to magical agencies</i>. -It is, of course, the case that any given difference -between the responses of an animal to the same situation<span class="pagenum"><a id="Page_242"></a>[242]</span> -depends upon some <i>particular</i> difference in the animal. Each -immunity, for example, has its detailed representation in an -altered condition of the blood or other bodily tissue. In -general the changes in an animal which cause changes in its -behavior to the same situation are fully enumerated in a -list of the bodily changes concerned. That is, whatever -changes may be supposed to have taken place in the animal’s -vital force, spiritual essence, or other magical bases for life -and thought, are useless for scientific explanation and control -of behavior.</p> - -<p>No competent thinker probably doubts this in the case of -such changes as are referred to by hunger, sleep, fatigue, so-called -‘functional’ diseases and immunity, and those who do -doubt it in the case of mental growth and learning seem to -represent an incomplete evolution from supernatural, or -rather infrascientific, thinking. There may be in behavior -a surplus beyond what would be predictable if the entire -history of every atom in the body was known—a surplus -necessarily attributable to changes in the animal’s incorporeal -structure. But scientific thinkers properly refuse -to deliberately count upon such a surplus.</p> - -<p><i>Every response or change in response of an animal is then -the result of the interaction of its original knowable nature and -the environment.</i> This may seem too self-evident a corollary -for mention. It should be so, but, unfortunately, it is not. -Two popular psychological doctrines exist in defiance of it. -One is the doctrine that the movements of early infancy are -random, the original nature of the animal being entirely -indifferent as to what movement shall be made upon a given -stimulus. But no animal can have an original nature that -does not absolutely prescribe just what the response shall -be to every stimulus. If the movements are really random, -they occur by virtue of some force that works at random.<span class="pagenum"><a id="Page_243"></a>[243]</span> -If the movements are really the result of the action of the environment -on the animal’s nature, they are never random. -A baby twiddles his thumbs or waves his legs for exactly the -same sort of reason that a chick pecks at a worm or preens -its wing.</p> - -<p>The other doctrine which witnesses to neglect of the -axiom that behavior is the creation of the environment, acting -on the animal’s nature, is the doctrine that the need -for a certain behavior helps to create it, that being in a -difficulty tends in and of itself to make an animal respond so -as to end the difficulty.</p> - -<p>The truth is that to a difficulty the animal responds by -whatever its inherited and acquired nature has connected -with the special form of difficulty and that in many animals -the one response of those thus provided which relieves the -difficulty is selected and connected more firmly with that -difficulty’s next appearance. The difficulty acts only as a -stimulus to the animal’s nature and its relief acts only as a -premium to the connection whereby it was relieved. The -law of original behavior, or the law of instinct, is then that -<i>to any situation an animal will, apart from learning, respond -by virtue of the inherited nature of its reception-, connection- -and action-systems</i>.</p> - -<p>The inquiry into the laws of learning to be made in this -essay is limited to those aspects of behavior which the term -has come historically to signify, that is, to intellect, skill, -morals and the like.</p> - -<p>For the purposes of this essay it is not necessary to decide -just what features of an animal’s behavior to include under -intellect, skill, morals and the like. The statements to be -made will fit any reasonable dividing line between behavior -on the one side and mere circulation, digestion, excretion -and the like on the other. There should in fact be no clear<span class="pagenum"><a id="Page_244"></a>[244]</span> -dividing line, since there is no clear gap between those -activities which naturalists have come to call behavior and -the others.</p> - -<p>The discussion will include: First, a description of two -laws of learning; second, an argument to prove that no additional -forces are needed—that these two laws explain all -learning; and third, an investigation of whether these two -laws are reducible to more fundamental laws. I shall also -note briefly the consequences of the acceptance of these laws -in one sample case, that of the study of mental evolution.</p> - -<h3><span class="smcap">Provisional Laws of Acquired Behavior or Learning</span></h3> - -<p>The Law of Effect is that: <i>Of several responses made to -the same situation, those which are accompanied or closely -followed by satisfaction to the animal will, other things being -equal, be more firmly connected with the situation, so that, -when it recurs, they will be more likely to recur; those which -are accompanied or closely followed by discomfort to the animal -will, other things being equal, have their connections with -that situation weakened, so that, when it recurs, they will be -less likely to occur. The greater the satisfaction or discomfort, -the greater the strengthening or weakening of the bond.</i></p> - -<p>The Law of Exercise is that: <i>Any response to a situation -will, other things being equal, be more strongly connected with -the situation in proportion to the number of times it has been -connected with that situation and to the average vigor and duration -of the connections.</i></p> - -<p>These two laws stand out clearly in every series of experiments -on animal learning and in the entire history of the -management of human affairs. They give an account of -learning that is satisfactory over a wide range of experience,<span class="pagenum"><a id="Page_245"></a>[245]</span> -so long as all that is demanded is a rough and general means -of prophecy. We can, as a rule, get an animal to learn a -given accomplishment by getting him to accomplish it, -rewarding him when he does, and punishing him when he -does not; or, if reward or punishment are kept indifferent, -by getting him to accomplish it much oftener than he does -any other response to the situation in question.</p> - -<p>For more detailed and perfect prophecy, the phrases -‘result in satisfaction’ and ‘result in discomfort’ need further -definition, and the other things that are to be equal need -comment.</p> - -<p>By a satisfying state of affairs is meant one which the -animal does nothing to avoid, often doing such things as -attain and preserve it. By a discomforting or annoying -state of affairs is meant one which the animal commonly -avoids and abandons.</p> - -<p>The satisfiers for any animal in any given condition cannot -be determined with precision and surety save by observation. -Food when hungry, society when lonesome, sleep -when fatigued, relief from pain, are samples of the common -occurrence that what favors the life of the species satisfies -its individual members. But this does not furnish a completely -valid rule.</p> - -<p>The satisfying and annoying are not synonymous with -favorable and unfavorable to the life of either the individual -or the species. Many animals are satisfied by deleterious -conditions. Excitement, overeating, and alcoholic intoxication -are, for instance, three very common and very potent -satisfiers of man. Conditions useful to the life of the species -in moderation are often satisfying far beyond their useful -point: many conditions of great utility to the life of the -species do not satisfy and may even annoy its members.</p> - -<p>The annoyers for any animal follow the rough rule that<span class="pagenum"><a id="Page_246"></a>[246]</span> -alterations of the animal’s ‘natural’ or ‘normal’ structure—as -by cuts, bruises, blows, and the like,—and deprivations -of or interference with its ‘natural’ or ‘normal’ activities,—as -by capture, starvation, solitude, or indigestion,—are intolerable. -But interference with the structure and functions -by which the species is perpetuated is not a sufficient -criterion for discomfort. Nature’s adaptations are too -crude.</p> - -<p>Upon examination it appears that the pernicious states of -affairs which an animal welcomes are not pernicious <i>at the -time, to the neurones</i>. We learn many bad habits, such as -morphinism, because there is incomplete adaptation of all -the interests of the body-state to the temporary interest of -its ruling class, the neurones. So also the unsatisfying -goods are not goods to the neurones at the time. We neglect -many benefits because the neurones choose their immediate -advantage. The neurones must be tricked into permitting -the animal to take exercise when freezing or quinine when -in a fever, or to free the stomach from certain poisons.</p> - -<p>Satisfaction and discomfort, welcoming and avoiding, thus -seem to be related to the maintenance and hindrance of the -life processes of the neurones rather than of the animal as a -whole, and to temporary rather than permanent maintenance -and hindrance.</p> - -<p>The chief life processes of a neurone concerned in learning -are absorption of food, excretion of waste, reception and -conduction of the nerve impulse, and modifiability or change -of connections. Of these only the latter demands comment.</p> - -<p>The connections formed between situation and response -are represented by connections between neurones and neurones, -whereby the disturbance or neural current arising in -the former is conducted to the latter across their synapses. -The strength or weakness of a connection means the greater<span class="pagenum"><a id="Page_247"></a>[247]</span> -or less likelihood that the same current will be conducted -from the former to the latter rather than to some other place. -The strength or weakness of the connection is a condition -of the synapse. What condition of the synapse it is remains -a matter for hypothesis. Close connection might mean protoplasmic -union, or proximity of the neurones in space, or a -greater permeability of a membrane, or a lowered electrical -resistance, or a favorable chemical condition of some other -sort. Let us call this undefined condition which parallels -the strength of a connection between situation and response -the intimacy of the synapse. Then the modifiability or -connection changing of a neurone equals its power to alter -the intimacy of its synapses.</p> - -<p>As a provisional hypothesis to account for what satisfies -and what annoys an animal, I suggest the following:—</p> - -<p>A neurone modifies the intimacy of its synapses so as to -keep intimate those by whose intimacy its other life processes -are favored and to weaken the intimacy of those -whereby its other life processes are hindered. The animal’s -action-system as a whole consequently does nothing to avoid -that response whereby the life processes of the neurones -other than connection-changing are maintained, but does -cease those responses whereby such life processes of the -neurones are hindered.</p> - -<p>This hypothesis has two important consequences. First: -Learning by the law of effect is then more fully adaptive for -the neurones in the changing intimacy of whose synapses -learning consists, than for the animal as a whole. It is -adaptive for the animal as a whole only in so far as his organization -makes the neurones concerned in the learning -welcome states of affairs that are favorable to his life and -that of his species and reject those that are harmful.</p> - -<p>Second: A mechanism in the neurones gives results in<span class="pagenum"><a id="Page_248"></a>[248]</span> -the behavior of the animal as a whole that seem beyond -mechanism. By their unmodifiable abandonment of certain -specific conditions and retention of others, the animal as a -whole can modify its behavior. Their one rule of conduct -causes in him a countless complexity of habits. The learning -of an animal is an instinct of its neurones.</p> - -<p>I have limited the discussion to animals in whom the connection-system -is a differentiated organ, the neurones. In -so far as the law of effect operates in an animal whose connection-system -is not anatomically distinguishable and is -favored and hindered in its life by the same conditions that -favor and hinder the life of the animal as a whole, the satisfying -and annoying will be those states of affairs which the -connection-system, whatever it be, maintains and abandons.</p> - -<p>The other things that have to be equal in the case of the -law of effect are: First, the frequency, energy and duration -of the connection,—that is, the action of the law of exercise; -second, the closeness with which the satisfaction is -associated with the response; and, third, the readiness of the -response to be connected with the situation.</p> - -<p>The first of these accessory conditions requires no comment. -A slightly satisfying or indifferent response made -often may win a closer connection than a more satisfying -response made only rarely.</p> - -<p>The second is most clearly seen in the effect of increasing -the interval between the response and the satisfaction -or discomfort. Such an increase diminishes the rate of -learning. If, for example, four boxes were arranged so that -turning a button caused a door to open (and permit a cat -to get freedom and food) in one, five, fifty and five hundred -seconds, respectively, a cat would form the habit of prompt -escape from the first box most rapidly and would almost -certainly never form that habit in the case of the fourth.<span class="pagenum"><a id="Page_249"></a>[249]</span> -The electric shock administered just as an animal starts on -the wrong path or touches the wrong mechanism, is potent, -but the same punishment administered ten or twenty -seconds after an act will have little or no effect upon that -act.</p> - -<p>Close temporal sequence is not the only means of insuring -the connection of the satisfaction with the response producing -it. What is called attention to the response counts also. -If a cat pushes a button around with its nose, while its main -occupation, the act to which its general ‘set’ impels it, to -which, we say, it is chiefly attentive, is that of clawing at -an opening, it will be less aided in the formation of the habit -than if it had been chiefly concerned in what its nose was -doing. The successful response is as a rule only a part of all -that the animal is doing at the time. In proportion as it -is an eminent, emphatic part of it, learning is aided. Similarly -discomfort eliminates most the eminent, emphatic -features of the total response which it accompanies or -shortly follows.</p> - -<p>The third factor, the susceptibility of the response and -situation to connection, is harder to illustrate. But, apparently, -of those responses which are equally strongly connected -with a situation by nature and equally attended to, -some are more susceptible than others to a more intimate -connection.</p> - -<p>The things which have to be equal in the case of the law -of exercise are the force of satisfyingness; that is, the -action of the law of effect, and again the readiness of -the response to be connected with the situation.</p> - -<p>The operation of the laws of instinct, exercise and effect -is conditioned further by (1) what may be called the law -of assimilation or analogy,—that a situation, especially -one to which no particular response is connected by original<span class="pagenum"><a id="Page_250"></a>[250]</span> -nature or previous experience, may connect with whatever -response is bound to some situation <i>much like it</i>,—and (2) -by the law of partial activity—that more or less of the -total situation may be specially active in determining the -response.</p> - -<p>The first of these laws is a result of the facts that conduction -in the neurones follows the line of least resistance or -closest connection, that the action-system is so organized -that certain responses tend to be made in their totality if -at all, and that slightly different situations may, therefore, -produce some one response, the effects of their differences -being in the accessories of that response.</p> - -<p>The second law is a result of the facts that the situation, -itself a compound, produces a compound action in the neurones, -and that by reason of inner conditions, the relative -intensities of different parts of the compound may vary. -The commonest response will be that due to the modal -condition of the neural compound, but every condition -of the compound will have its response.</p> - -<h3><span class="smcap">The Adequacy of the Laws of Exercise and Effect</span></h3> - -<p>Behavior has been supposed to be modified in accordance -with three other principles or laws besides the law of exercise -and the law of effect. Imitation is often used as a name -for the supposed law that the perception of a certain response -to a situation by another animal tends in and of itself -to connect that response to that situation. Common -acceptance has been given to more or less of the law that -the idea of an act, or of the result of an act, or of the immediate -or remote sensations produced by the act, tends -in and of itself to produce the act. Such a law of ‘suggestion’<span class="pagenum"><a id="Page_251"></a>[251]</span> -or ‘ideo-motor’ action may be phrased differently, -but in whatever form, it insists that the bond between a -situation and some conscious representation of a response -or of its consequences can do the work of the bond between -the situation and the response itself. In acts of reasoning -man has been supposed to connect with a given situation a -response that could never have been predicted merely from -knowledge of what responses were connected with that -situation by his original nature or had been connected with -it by the laws of exercise and effect. Inference has been -supposed to create bonds in and of itself and to be above -the mere laws of habit.</p> - -<p>Various forms of statement, most of them vague, have -been and would be used in describing the potency of a perceived -response, a thought-of response, or a train of inference, -to produce a response and bind it to the given total -situation. Any forms will do for the present argument, -since all forms mean to assert that responses can be and -often are bound to situations otherwise than by original -bodily nature, satisfaction, discomfort, disuse and use. I -shall try to show that they cannot; that, on the contrary, -the laws of exercise and effect account for all learning.</p> - -<p><i>The facts of imitation in human and animal behavior are -explainable by the laws of instinct, exercise and effect.</i></p> - -<p>Some cases of imitation are undoubtedly mere instincts -in which the situation responded to is an act by another of -the same species. If the baby smiles at a smile, it is because -of a special, inborn connection between that sight -and that act,—he smiles at a smile for just the same reason -that he draws down his mouth and wails at harsh -words. At that stage of his life he does not imitate other -simple acts. A man runs <i>with</i> a crowd for the same reason -that he runs <i>from</i> a tiger. Returning a blow is no more due -to a general tendency to imitate than warding it off is.</p> - -<p><span class="pagenum"><a id="Page_252"></a>[252]</span></p> - -<p>Other cases of imitation are mere adjuncts to the ordinary -process of habit-formation. In the first place, the act of another, -or its result, may serve as a model by which the satisfyingness -of one’s own responses are determined. Just as -the touch and taste of food tells a baby that he has got it -safely into his mouth, so the sound of a word spoken by another -or the sight of another performing some act of skill -tells us whether our pronunciation or technique is right or -wrong.</p> - -<p>In the second place, the perception of another’s act may -serve as a stimulus to a response whereby the situation is -altered into one to which the animal responds from habit by -an act like the one perceived. For example, the perception -of another making a certain response (<i>A</i>) to a situation (<i>B</i>) -may lead in me by the laws of habit to a response (<i>C</i>) -which puts me in a situation (<i>D</i>) such that the response (<i>A</i>) -is made by me by the laws of habit. Suppose that by previous -training the act of taking off my hat (<i>A</i>) has become -connected as response to the situation (<i>D</i>), ‘thought of hat -off,’ and suppose that with the sight of others uncovering -their heads (<i>A</i>) in church (<i>B</i>) there has, again by previous -habituation, been connected, as response (<i>C</i>), ‘thought of -hat off.’ Then the sight of others uncovering their heads -would by virtue of the laws of habit lead me to uncover. -Imitation of this sort, where the perception of the act or -condition in another gives rise to the idea of performing the -act or attaining the condition, the idea in turn giving rise -to the appropriate act, is certainly very common.</p> - -<p>There may be cases of imitation which cannot be thus -accounted for as special instinctive responses to the perception -of certain acts by the same acts, as habits formed under -the condition that the satisfyingness of a response is its -likeness to the perceived act of another, or as the connection<span class="pagenum"><a id="Page_253"></a>[253]</span> -of two habits, one of getting, from the perceived act of another, -a certain inner condition, the other of getting, from -this inner condition, the act in question. There may be, -that is, cases where the perceived act of another in and of -itself creates a connection.</p> - -<p>It is apparently taken for granted by a majority of writers -on human behavior that cases of such direct mental infection, -as it were, not only exist, but are the rule. I am -unable to find proof of such cases, however. Those commonly -quoted are far from clear. Learning to talk in the -human infant, for example, the stock case of imitation as a -direct means of learning, offers only very weak and dubious -evidence. Since what is true of it holds substantially -for the other favored cases for learning by imitation, I -shall examine it at some length.</p> - -<p>Let us first be clear as to the alternative explanations of -linguistic imitation. The first is that seeing the movements -of another’s mouth-parts or hearing a series of word-sounds -in and of itself produces the response of making that series -of sounds or one like it.</p> - -<p>The other is that the laws of instinct and habit are adequate -to explain the fact in the following manner: A -child instinctively produces a great variety of sounds and -sound-series. Some of these, accepted as equal to words by -the child’s companions, are rewarded, so that the child -learns by the law of effect to use them in certain situations to -attain certain results. It is possible also that a child instinctively -feels a special satisfaction at babbling when -spoken to and a special satisfaction at finding the sound he -makes like one that rings in the ears of memory and has -meaning. The latter would be like the instinctive satisfaction -apparently felt in constructing an object which is like -some real object whose appearance and meaning he knows.</p> - -<p><span class="pagenum"><a id="Page_254"></a>[254]</span></p> - -<p>A child also meets frequently the situations ‘say dada,’ -‘say mama,’ ‘say good night’ and the like,<a id="FNanchor_41" href="#Footnote_41" class="fnanchor">[41]</a> and is rewarded -when his general babble produces something like the word -spoken to him. He thus, by the law of effect, learns to respond -to any ‘say’ situation by making <i>some</i> sound and to -each of many ‘say’ situations by making an appropriate -sound, and to feel satisfaction at duplicating these words -when heard. According to the amount of such training, -the tendency to respond to words spoken to him by making -some sound may become very strong, and the number -of successful duplications very large. Satisfaction may be -so connected with saying words that the child practices -them by himself orally and even in inner speech. The second -alternative relies upon the instinct of babbling, and the -satisfaction of getting desirable effects from speech, either -the effect which the word has by its meaning as a request -(‘water,’ ‘milk,’ ‘take me outdoors’ and the like) or the -effect which it has by its mere sound upon companions -who notice, pet or otherwise reward a child for linguistic -progress.</p> - -<p>There are many difficulties in the way of accepting the -first alternative. First of all, no one can believe that <i>all</i> -of a child’s speech is acquired by direct imitation. On -many occasions the process is undoubtedly one of the production -of many sounds, irrespective of the model given, and -the selection of the best one by parental reward. Any student -who will try to get a child who is just beginning to -speak, to say cat, dog and mouse and will record the -sounds actually made by the child in the three cases, will -find them very much alike. There will in fact be little<span class="pagenum"><a id="Page_255"></a>[255]</span> -that even <i>looks</i> like direct imitation until the child has -‘learned’ at least forty or fifty words.</p> - -<p>The second difficulty lies in the fact that different children, -in even the clearest cases of the imitation of one -sound, vary from it in so many directions. A list of all the -sounds made in response to one sound heard is more suggestive -of random babble as modified by various habits of -duplicating sounds, than of a direct potency of the model. -Ten children of the same age may, in response to ‘Christmas,’ -say, kiss, kissus, krismus, mus, kim, kimus, kiruss, -i-us and even totally unlike vocables such as hi-yi or ya-ya.</p> - -<p>The third difficulty is that in those features of word-sounds -which are hard to acquire, such as the ‘th’ sound, -direct imitation is inadequate. The teacher has recourse to -trial and chance success, the spoken word serving as a model -to guide satisfaction and discomfort. In general no sound -not included in the instinctive babble of children seems to be -acquired by merely hearing and seeing it made.</p> - -<p>A fourth difficulty is that by the doctrine of direct imitation -it should not be very much more than two or three -times as hard to repeat a two- or three-syllable series as to -repeat a single syllable. It is, in fact, enormously harder. -This is, of course, just what is to be expected if learning a -sound means the selection from random babbling plus previous -habits. If, for instance, a child makes thirty monosyllabic -sounds like pa, ga, ta, ma, pi, gi, li, mi, etc., there -is, by chance, one chance in thirty that in response to a -word or phrase he will make that one-syllable sound of his -repertory which is most like it, but there is only one chance -in nine hundred that he will make that <i>two-syllable</i> combination -of his repertory which is most like it.</p> - -<p>On the other hand, two objections will be made to the opposite -view that the word spoken acts only as a model to<span class="pagenum"><a id="Page_256"></a>[256]</span> -select from responses otherwise caused, or as a stimulus to -habits already existing. First it will be said that clear, indubitable -repetitions of words never practiced by the child, -either as totals or in their syllables separately, <i>do</i> occur,—that -children do respond by repeating a word in cases where -full knowledge of all their previous habits would give no -reason to expect them to make such a connection. To this -the only retort is that such observations should be based on -a very delicate and very elaborate record of a child’s linguistic -history, and that until they are so made, it is wise to -withhold acceptance.</p> - -<p>The second objection is that the rapid acquisition of a -vocabulary such as occurs in the second and third year is -too great a task to be accomplished by the laws of exercise -and effect alone. This objection is based on an overestimation -of the variety of sounds which children of the ages in -question make. For example, a child who says 250 words, -including say 400 syllables, comprising say 300 syllables -which, when properly pronounced, are distinguishable, may -actually use less than 50 distinguishable syllables. <i>Ba</i>, may -stand for the first syllable of father, water, barn, park and -the like. <i>Ki</i> may stand for cry, climb, and even carry. -For a child to say a word commonly means that he makes -a sound which his intimate companions can recognize as his -version of that word. A child who can produce something -like each one of a thousand words upon hearing them, may -do so from actual control over less than a hundred syllables. -If we suppose him to have acquired the habits, -first, of saying <i>something</i> in such a case, second, of responding -to a certain hundred sounds when perceived or remembered -by making, in each case, a similar sound, and, -third, of responding to any other sound when perceived or -remembered, by making that sound of his own repertory<span class="pagenum"><a id="Page_257"></a>[257]</span> -which is most like it,<a id="FNanchor_42" href="#Footnote_42" class="fnanchor">[42]</a> we can account for a thousand ‘imitations,’ -and still not have made a large demand upon childish -powers of learning.</p> - -<p>No one should pretend to have disproved direct imitation -in the case of learning to talk until he has subjected all these -and other matters to crucial experiments. But the burden -of proof does seem to belong upon those who deny the adequacy -of the laws of exercise and effect. In so far as the -choice is between accepting or rejecting a general law that, -other things being equal, the perception of a response in -another produces that response, we surely must reject it. -Some of the cases of imitation may be unexplained by the -laws of exercise and effect. But for others no law of imitation -is required. And of what should happen by such a law -not over a trivial fraction at most does happen.</p> - -<div class="blockquote"> - -<p class="center"><i>The idea of a response is in and of itself unable to produce -that response.</i></p> - -</div> - -<p>The early students of behavior, considering human behavior -and emphasizing behavior that was thought about -and purposive, agreed that the sure way to connect a response -with a situation was to choose, or will, or consent to, -that response. Later students still agreed that to think -about the response in some way, to have an image of it or of -the sensations caused in you by previous performances of it, -was a strong provocative to it. To get a response, get some -sort of conscious representative of it, has been an acceptable -maxim. Medicine, education and even advertising have -based their practice upon the theory that ideas tended to -issue in the particular sort of acts that they were ideas of.</p> - -<p>The laws of exercise and effect, on the contrary, if they<span class="pagenum"><a id="Page_258"></a>[258]</span> -are the sole laws of modifiability, insist that the thought of -an act will produce that act only if the act has been connected -with that thought (and without resulting discomfort) -in the animal’s past.</p> - -<p>It seems plausible that there should be a peculiar bond -between the thought of a response and the response. The -plausibility is due to two reasons, one of which is sound but -inadequate, the other being, in my opinion, entirely unsound. -The first reason is that, as a mere matter of fact, -the thought of a response does so often produce it. The -second is that an idea of a response seems a natural and -sufficient cause for it to appear. The first reason is inadequate -to justify any law of the production of a response by -its image or other representative, since evidence can be -found to show that when a response is produced by an idea -of it, it has been already bound to that idea by repetition or -satisfaction. The second reason is unsound because, even -if responses are brought to pass occasionally by their -images, that is surely an extremely rare and unnatural -method.</p> - -<p>It is certain that in at least nine cases out of ten a response -is produced, not by an image or other representation -of it, but by a situation nowise like it or any of its accessories. -Hunger and the perception of edible objects, far outweigh -ideas of grasping, biting and swallowing, as causes -of the eating done in the world. Objects sensed, not images -of eye-movements, cause a similar overwhelming majority -of the eye’s responses. We walk, reach and grasp -on most occasions, not because of anticipatory images of -how it will feel to do so or verbal descriptions to ourselves -of what we are to do, but because we are stimulated by the -perception of some object.</p> - -<p>It is also certain that the idea of a response may be impotent<span class="pagenum"><a id="Page_259"></a>[259]</span> -to produce it. I cannot produce a sneeze by thinking -of sneezing. A child may have, in the case of some -simple bodily act, which he has done in response to certain -situations thousands of times, as adequate ideas of it as are -possessed by others, and yet be utterly unable to make himself -do it; many adults show this same phenomenon, for -instance, in the case of swallowing a pill. And, of course, -one can have ideas of running a mile in two minutes, jumping -a fence eight feet high, or drawing a line exactly equal -to a hundred millimeter line, just as easily as of running the -mile in ten minutes, or jumping four feet.</p> - -<p>It is further certain that the thought of doing one thing -very often results in the man’s doing something quite different. -The thought of moving the eyes smoothly without -stops along a line of print has occurred to many people, who -nevertheless actually did as a result move the eyes in a series -of jumps with long stops.</p> - -<p>It is further certain that in many cases where an animal -does connect a given response with the image or thought of -that response, the connection has been built up by the laws -of exercise and effect. Such cases as appropriate responses -to, ‘I will go to bed,’ ‘I will get up,’ ‘I will eat,’ ‘I will write -a letter,’ ‘I will read,’ or to the corresponding commands, -requests or suggestions, are observably built up by training. -The appropriate response follows the idea only if it has, -by repetition or reward, been connected with it or something -like it. If the only requirement in moral education were to -have the idea of the right act at the right time, the lives of -teachers and parents would be greatly alleviated. But the -decision to get up, or the idea of getting up or of being up, -is futile until the child has connected therewith the actual -act of getting up.</p> - -<p>The defender of the direct potency of conscious representatives<span class="pagenum"><a id="Page_260"></a>[260]</span> -of a response to produce it may be tempted to complain -at this point that what the laws of exercise and effect -do is to reduce the strength of competing ideas, and leave the -idea, say of getting up, free to exercise its direct potency. -The complaint shows a weak sense for fact. The ordinary -child is not a Hamlet, nor is he beguiled by the imagined -delights of staying in bed, nor repelled by the image of getting -up out of it. On the contrary, he may be entirely willing -to <i>think of</i> getting up. It is the actual delights that -hold him, the actual discomforts that check him, and the -only way to be sure that he will get up is so to arrange matters -that it is more satisfactory to him to get up than not to -when the situation, whatever it be, that is to suggest that -response, makes its appearance.</p> - -<p>The experience of every schoolroom shows that it is not -enough to get the idea of an act. The act must have gone -with that idea or be now put with it. The bond must be -created. Responses to the suggestions of language, whether -addressed to us by others or by ourselves in inner speech, -in a very large majority of cases owe their bonds to the laws -of exercise and effect. We learn to do what we are told, -or what we tell ourselves, by doing <i>something</i> and rejecting -or retaining what we do by virtue of its effects. So also in -the case of a majority of responses to the suggestions of other -than verbal imagery.</p> - -<p>The idea of a response, like the perception of a response -by another, acts often as a guide to response <i>ex post facto</i> by -deciding what shall be satisfying. Where superficial inspection -leaves the impression that the idea creates the act, a -little care often shows it to have only selected from the acts -produced by instinct and habit. For example, let the reader -think of some act never performed hitherto, such as putting -his left middle finger upon the upper right hand corner of<span class="pagenum"><a id="Page_261"></a>[261]</span> -this page, and make the movement. It may seem at first -sight that having the idea entirely unopposed was the sufficient -cause of the act. But careful experiment, including, -for instance, the closure of the eyes and anesthesia of the -fingers will reveal that the original propulsion of the idea is -not to just that act, but to many possibilities, and that its -chief potency lies in the fact that not to get the finger to -that point is annoying, and that consequently the organism -is at peace only when the act is done.</p> - -<p>So far it has been shown that: The majority of responses -are not produced by ideas of them. The idea of a response -may be impotent to produce it. The idea of one act may -produce a different, even an opposite act. When an idea -seems to produce a response in and of itself, it may really act -by determining the satisfyingness of responses otherwise -made. These facts are sufficient to destroy the pretensions -of any general law that the image of an act will, other things -being equal, produce it. But the possibility that such an -image may occasionally exercise this peculiar potency remains.</p> - -<p>I despair of convincing the reader that it does not. Man -is the only animal possessing a large fund of ideas of acts, -and man’s connection-system is so complex and his ideas of -acts are so intricately bound to situations that have by -use and effect produced those acts, that the proof of this -negative is a practical impossibility. But it is possible to -show that even the most favored cases for the production -of a response by securing an ideal representation of it may -be explainable by use and effect alone.</p> - -<p>The extreme apparent potency of ideas representing acts -to produce them regardless of bonds of use or effect is, of -course, witnessed in the phenomena of suggestion in hypnosis -and allied states. To try to reduce these phenomena<span class="pagenum"><a id="Page_262"></a>[262]</span> -to consequences of the laws of habit may seem fanatical. -Here, it will be said, are the crucial cases where the idea of -an act, if freed from all effects of opposing ideas, does inevitably -produce the act so far as it is a possibility for the -animal’s action-system.</p> - -<p>That is precisely what I cannot find proof of.</p> - -<p>Efficient suggestions to hypnotized subjects, on the contrary, -are often ambiguous in the sense that they seem as -likely to arouse a situation <i>to which the act has been bound -by the law of habit</i> as to arouse an idea of the act. Often -they are far better suited to the former purpose. Direct -commands—Walk, Dance, Get up, Sit down—obviously -will operate by the law of habit provided the situations -connected with disobedience are excluded. This is also -the case with such indirect suggestions as ‘This is a knife -(stick).’ ‘This is your sword (broom).’ ‘Have a cigar -(a pen).’</p> - -<p>The release of a suggestion from inhibitions may as well -be the release from <i>ideas connected as antecedents with</i> not -performing the act as the release from <i>ideas of</i> not performing -it. It is a question of fact whether, to get an act done -by the subject, one must arouse in him an idea to which or -to a part of which or to something like which the act has been -bound by use or effect, or may arouse simply an idea of the -act.</p> - -<p>Finally, if an idea has a tendency to connect with a certain -response, over and above the bonds due to exercise and -effect, it should <i>always</i> manifest that tendency. If the -connection is not made, it must be due to the action of some -contrary force. It is less my duty to show that the laws of -habit can account for hypnotic suggestibility, obsessions, -and the like, than it is my opponents’ duty to explain why a -man can spend a half day in hospitably welcoming a hundred<span class="pagenum"><a id="Page_263"></a>[263]</span> -ideas of acts and yet perform no one of them, save those in -the case of which he has learned to do the thing when he -thinks of doing it. Again, how can the mere addition of -the idea of a future date to the idea of an act so utterly -deprive it of present potency.</p> - -<p>In view of all these facts it seems probable that ideas of -responses act in connection just as do any other situations, -and that the phenomena of suggestion and ideo-motor -action really mean that any idea will, except for competing -ideas, produce the response, not that <i>is like it</i>, but that <i>has -gone with it</i>, or with some idea like it.</p> - -<div class="blockquote"> - -<p class="center"><i>Rational connections are, in their causation, like any -others, the difference being in what is connected.</i></p> - -</div> - -<p>It remains to ask whether situation and response are -bound together in the case of reasoning by any other forces -than the forces of repetition, energy and satisfaction? Do -the laws of inferential thinking transcend the laws of exercise -and effect? Or does the mind, even in these novel and -constructive responses, do only what it is forced to do by -original nature or has done without discomfort?</p> - -<p>To defend the second alternative involves the reduction -of the processes of abstraction, association by similarity and -selective thinking to mere secondary consequences of the -laws of exercise and effect. This I shall try to do.</p> - -<p>The gist of the fact of abstraction is that response may be -made to some elements or aspects of a situation which have -never been experienced in isolation, and may be made to the -element in question regardless of the gross total situation in -which it inheres. A baby thus learns to respond to its -mother’s face regardless of what total visual field it is a part -of. A child thus learns to respond by picking out any red -object, regardless of whether the redness be in an apple, a<span class="pagenum"><a id="Page_264"></a>[264]</span> -block, a pencil, a ribbon or a ball. A student thus learns to -respond to any plane surface inclosed by three straight lines -regardless of its size, shape, color or other than geometrical -meaning.</p> - -<p>What happens in such cases is that the response, by being -connected with many situations alike in the presence of the -element in question and different in other respects, is bound -firmly to that element and loosely to each of its concomitants. -Conversely any element is bound firmly to any one response -that is made to all situations containing it and very, very -loosely to each of those responses that are made to only a -few of the situations containing it. The element of triangularity, -for example, is bound firmly to the response of saying -or thinking ‘triangle’ but only very loosely to the response -of saying or thinking white, red, blue, large, small, iron, steel, -wood, paper and the like. A situation thus acquires bonds -not only with some response to it as a gross total, but also -with responses to each of its elements that has appeared in -any other gross totals.</p> - -<p>Appropriate response to an element regardless of its concomitants -is a necessary consequence of the laws of exercise -and effect if an animal learns to make that response to the -gross total situations that contain the element and not to -make it to those that do not. Such prepotent determination -of the response by one or another element of the situation -is no transcendental mystery, but, given the circumstances, -a general rule of all learning. The dog who responds appropriately -to ‘beg’ no matter when, where, or by whom -spoken, manifests the same laws of behavior. There is no -difficulty in understanding how each element of a situation -may come to tend to produce a response peculiar to it as -well as to play its part in determining the response to the -situation as a total. There may be some difficulty in understanding<span class="pagenum"><a id="Page_265"></a>[265]</span> -how each element of a situation comes to be <i>felt</i> -whereas before only the gross total was felt. The change in -consciousness from the ‘big, blooming, buzzing confusion’ -to an aggregate of well-defined percepts and images, which -accompanies the change in behavior from response to totals -to response to parts or elements, may be mysterious. With -the change in consciousness, however, we are not now concerned. -The <i>behavior</i> of man and other animals toward the -abstract elements of color, size, number, form, time or value -is explained by the laws of instinct, exercise and effect.</p> - -<p>When the perception or thought of a fact arouses the -thought of some other fact identical in part with the former -fact, we have so-called association by similarity. An -element of the neurone-action is prepotent in determining -the succeeding neurone-action. The particular way in -which it determines it is by itself continuing and making -connection with other associates. These it possesses by -virtue of the law of exercise and effect.</p> - -<p class="tb">The changes in behavior classified under intellect and -morality seem then to be all explainable by the two laws -of exercise and effect. The facts of imitation really refer -to certain specific original connections or to the efficiency -of a model in determining what shall satisfy or to the provision -of certain instructive situations in the form of the -behavior of other animals. The facts variously referred to -as suggestion, ideo-motor action or the motor power of ideas, -really refer to the fact, common in the human animal only, -that to those ideas that represent acts in thought the acts -are often bound as responses. The bonds are due to the -primary laws of effect and exercise. The facts of reasoning -really refer to the fact of prepotency of one or another -element in a situation in determining the response.</p> - -<p><span class="pagenum"><a id="Page_266"></a>[266]</span></p> - -<p>The reduction of all learning to making and rewarding -or avoiding and punishing connections between situation -and response allows changes in intellect and character to -be explained by changes in the neurones that are known -either to be or to be possible. I have elsewhere sketched -one such possible neural mechanism for the law of effect.<a id="FNanchor_43" href="#Footnote_43" class="fnanchor">[43]</a></p> - -<p>On the contrary, imitation, suggestion and reasoning, -as commonly described, put an intolerable burden upon -the neurones. To any one who has tried to imagine a -possible action in the neurones to parallel the traditional -power of the mere perception of an act in another or of -the mere representation of an act as done by oneself to -produce that act, this is a great merit. For the only -adequate psychological parallel of traditional imitation -and suggestion would be the original existence or the gratuitous -formation of a connection between (1) each neurone-action -corresponding to a percept of an act done by another -or to the idea of an act done by oneself and (2) the neurone-action -arousing that act. It is incredible that the neurone-action -corresponding to the perception of a response in -another, or to the idea of a response in oneself, or to the first -term in an association by similarity, should have, in and -of itself, a special power to determine that the next neurone-action -should be that paralleling the response in question. -And there is no possible physiological parallel of a power -to jump from premise to conclusion for no other reason -than the ideal fitness of the sequence.</p> - -<h3><span class="smcap">Simplifications of the Laws of Exercise and Effect</span></h3> - -<p>There has been one notable attempt to explain the facts -of learning by an even simpler theory than that represented<span class="pagenum"><a id="Page_267"></a>[267]</span> -in the laws of exercise and effect. Jennings has formulated -as an adequate account of learning the law that: “When -a certain physiological state has been resolved, through -the continued action of an external agent, or otherwise, -into a second physiological state, this resolution becomes -easier, so that in course of time it takes place quickly and -spontaneously” (‘Behavior of the Lower Organisms,’ p. 289). -“The law may be expressed briefly as follows:—<i>The -resolution of one physiological state into another becomes -easier and more rapid after it has taken place a number of -times.</i> Hence the behavior primarily characteristic for -the second state comes to follow immediately upon the first -state. The operations of this law are, of course, seen on -a vast scale in higher organisms in the phenomena which -we commonly call memory, association, habit formation -and learning” (<i>ibid.</i>, p. 291). This law may be expressed -conveniently as a tendency of a series of states</p> - -<p class="center">A -> B -> C -> D</p> - -<p class="noindent">to become</p> - -<p class="center">A -> D</p> - -<p class="noindent">or</p> - -<p class="center">A -> B¹ -> C¹ -> D</p> - -<p class="noindent">B¹ and C¹ being states B and C passed rapidly and in a -modified way so that they do not result in a reaction but -are resolved directly into D.</p> - -<p>If Professor Jennings had applied to this law the same -rigorous analysis which he has so successfully employed -elsewhere, he would have found that it could be potent -to cause learning only if supplemented by the law of effect -and then only for a fraction of learning.</p> - -<p>For, the situations being the same, the state A cannot -produce, at one time, now B and, at another time, abbreviated, -rudimentary B¹ instead of B. If A with S produces B -once, it must always. If D or a rudimentary B¹ is produced, -there must be something other than A; A must itself have<span class="pagenum"><a id="Page_268"></a>[268]</span> -changed. Something must have been added to or subtracted -from it. In Professor Jennings’ own words, “Since -the external conditions have not changed, the animal itself -must have changed” (<i>ibid.</i>, p. 286). And in adaptive -learning something related to the results of the S A connection -must have changed it.</p> - -<p>The series A—B—C—D does not become the series -A—D or A—B¹—C¹—D by magic. If B and C are -weakened and D is strengthened as sequents of A in response -to S, it is because something other than repetition -acts upon them. Repetition alone could not blow hot -for D and cold for B.</p> - -<p>Moreover, as a mere matter of fact, “the resolution of one -physiological state into another” through intermediate -states does not with enough repetition “become easier so -that in course of time it takes place quickly and spontaneously.”</p> - -<p>Paramecium does not change its response to, say, an obstacle -in the water, from swimming backward, turning to -one side and swimming forward by abbreviating and eventually -omitting the turn and the backward movement. -The schoolboy does not tend to count 1, 2, 10 or to say -a, b, z, or give ablative plurals after nominative singulars.</p> - -<p>Repetition of a series of physiological states in and of itself -on the contrary makes an animal increasingly <i>more</i> -likely to <i>maintain</i> the series <i>in toto</i>. It is hard to give the -first and then the last word of an oft repeated passage like -Hamlet’s soliloquy or the Lord’s Prayer, or to make readily -the first and then the last movement of writing a name or -address. Repetition never eliminates absolutely and eliminates -relatively the <i>less</i> often or <i>less</i> emphatically connected.</p> - -<p>Even if supplemented by the law of effect, so that some -force is at hand to change the effect of S upon the animal<span class="pagenum"><a id="Page_269"></a>[269]</span> -to A D instead of the original A B C D, the law of the -resolution of physiological states would be relevant to only a -fraction of learning. For example, let a cat or dog be given -an ordinary discrimination experiment, but so modified -that whether the animal responds by the ‘right’ or the -‘wrong’ act <i>he is removed immediately after the reward or -punishment</i>. That is, the event is either S R1 or S R2, -never S R1 R2. Let the experiment be repeated at intervals -so long that the physiological state, St. R1, or St. R2, -leading to the response R1 or R2 in the last trial, has -ceased before the next. The animal will come to respond to -S by R2 only, though R2 has never been reached by the -‘resolution’ of S R1 R2.</p> - -<p>Cats in jumping for birds or mice, men in playing -billiards, tennis or golf, and many other animals in many -other kinds of behavior, often learn as the dog must in -this experiment. The situation on different occasions is -followed by different responses, but by only one per -occasion. Professor Jennings was misled by treating as -general the special case where the situation itself includes a -condition of discomfort terminable only by a ‘successful’ -response or by the animal’s exhaustion or death.</p> - -<p>Assuming as typical this same limited case of response -to an annoying situation, so that success consists simply -in replacing the situation by another, Stevenson Smith -reduces the learning-process to the law of exercise alone. -He argues that,—</p> - -<p>“For instance, let an organism at birth be capable of -giving N reactions (a, b, c, ... N) to a definite stimulus -S and let only one of these reactions be appropriate. If -only one reaction can be given at a time and if the one -given is determined by the state of the organism at the -time S is received, there is one chance in N that it is the<span class="pagenum"><a id="Page_270"></a>[270]</span> -appropriate reaction. When the appropriate reaction is -finally given, the other reactions are not called into play, -S may cease to act, but until the appropriate reaction is -given let the organism be such that it runs through the -gamut of the others until the appropriate reaction is brought -about. As there are N possible reactions, the chances are -that the appropriate reaction will be given before all N -are performed. At the next appearance of the stimulus, -which we may call S₂, those reactions which were in the -last case performed, are, through habit, more likely to be -again brought about than those which were not performed. -Let <i>u</i> stand for the unperformed reactions. Then we have -N - <i>u</i> probable reactions to S₂. Habit rendering the -previously most performed reactions the most probable -throughout we should expect to find the appropriate reaction -in response to</p> - -<ul> -<li>S₁ contained in N.</li> -<li>S₂ contained in N - <i>u₁</i>.</li> -<li>S₃ contained in N - <i>u₁</i> - <i>u₂</i>.</li> -<li>...</li> -<li>S<i>ₙ</i> contained in N - <i>nu</i>, which approaches <i>one</i> as a limit.</li> -</ul> - -<p>Thus the appropriate reaction would be fixed through the -laws of chance and habit. This law of habit is that when -any action is performed a number of times under certain -conditions, it becomes under those conditions more and -more easily performed” (<i>Journal of Comparative Neurology -and Psychology</i>, 1908, Vol. XVIII, pp. 503-504).</p> - -<p>This hypothesis is, like Professor Jennings’, adequate to -account for only the one special case, and is adequate to -account for that only upon a further limitation of the number -of times that the animal may repeat any one of his varied -responses to the situation before he has gone through them<span class="pagenum"><a id="Page_271"></a>[271]</span> -all once, or reached the one that puts an end to the situation.</p> - -<p>The second limitation may be illustrated in the simple -hypothetical case of three responses, 1, 2 and 3, of which -No. 2 is successful. Suppose the animal always to go -through his repertory with <i>no</i> repetitions until he reaches 2 -and so closes the series.</p> - -<p>Only the following can happen:—</p> - -<ul> -<li>1 2</li> -<li>1 3 2</li> -<li>2</li> -<li>2</li> -<li>3 1 2</li> -<li>3 2</li> -</ul> - -<p class="noindent">and, in the long run, 2 will happen twice as often as 1 or 3 -happens.</p> - -<p>Suppose the animal to repeat each response of his repertory -six times before changing to another, the remaining -conditions being as above. Then only the following can -happen:—</p> - -<ul> -<li>1 1 1 1 1 1 2</li> -<li>1 1 1 1 1 1 3 3 3 3 3 3 2</li> -<li>2</li> -<li>2</li> -<li>3 3 3 3 3 3 1 1 1 1 1 1 2</li> -<li>3 3 3 3 3 3 2,</li> -</ul> - -<p class="noindent">and in the long run 2 will happen one third as often as 1 or 3 -and, though always successful, must, by Smith’s theory, -appear later and later, so that if the animal meets the -situation often enough, he will eventually fail utterly in it!</p> - -<p>Animals do, as a matter of fact, commonly repeat responses -many times before changing them,<a id="FNanchor_44" href="#Footnote_44" class="fnanchor">[44]</a> so that if only the law<span class="pagenum"><a id="Page_272"></a>[272]</span> -of exercise operated, learning would not be adaptive. It is -the <i>effect</i> of 2 that gives it the advantage over 1 and 3. Of -two responses to the same annoying situation, one continuing -and the other relieving it, an animal could never learn -to adopt the latter as a result of the law of exercise alone, -if the former was, originally, twice as likely to occur. 1 1 2 -would occur as often as 2 and exercise would be equal for -both. The convincing cases are, of course, those where -learning equals the strengthening to supremacy of an -originally very weak connection and the weakening of -originally strong bonds. An animal’s original nature may -lead it to behave as shown below:—</p> - -<ul> -<li>1 1 1 3 1 1 4 1 1 2</li> -<li>1 1 1 1 3 1 1 1 3 1 1 4 2</li> -<li>4 1 1 3 3 1 1 4 4 1 1 1 1 1 2, etc.,</li> -</ul> - -<p class="noindent">and yet the animal’s eventual behavior may be to react to -the situation always by 2. The law of effect is primary, -irreducible to the law of exercise.</p> - -<h3><span class="smcap">The Evolution of Behavior</span></h3> - -<p>The acceptance of the laws of exercise and effect as adequate -accounts of learning would make notable differences -in the treatment of all problems that concern learning. I -shall take, to illustrate this, the problem of the development -of intellect and character in the animal series, the phylogenesis -of intellectual and moral behavior.</p> - -<p>The difficulties in the way of understanding the evolution -of intellectual and moral behavior have been that neither -what had been evolved nor that from which it had been -evolved was understood.</p> - -<p>The behavior of the higher animals, especially man, was -thought to be a product of impulses and ideas which got<span class="pagenum"><a id="Page_273"></a>[273]</span> -into the mind in various ways and had power to arouse -certain acts and other ideas more or less mysteriously, in the -manner described by the laws of ideo-motor action, attention, -association by contiguity, association by similarity, -suggestion, imitation, dynamo-genesis and the like, with -possibly a surplus of acts and ideas due to ‘free will.’ The -mind was treated as a crucible in which a multifarious solution -of ideas, impulses and automatisms boiled away, -giving off, as a consequence of a subtle chemistry, an -abundance of thoughts and movements. Human behavior -was rarely viewed from without as a series of responses -bound in various ways to a series of situations. The student -of animal behavior passed as quickly as might be from -such mere externals to the inner life of the creature, making -it his chief interest to decide whether it had percepts, -memories, concepts, abstractions, ideas of right and wrong, -choices, a self, a conscience, a sense of beauty. The facts -in intellect and character that are due to learning, that are -not the inherited property of the species and that consequently -are beyond the scope of evolution in the race, -were not separated off from the facts of original nature. -The comparative psychologist misspent his energy on such -problems as the phylogenesis of the idea of self, moral -judgments, or the sentiment of filial affection.</p> - -<p>At the other extreme, the behavior of the protozoa was -either contemplated in the light of futile analogies,—for -instance, between discriminative reactions and conscious -choice, and between inherited instincts and memory,—or -studied crudely in its results without observation of what -the animals really did. The protozoa were regarded either -as potential ‘conscious selves’ or as drifting lumps turned -hither and thither by the direct effects of light, heat, gravity -and chemical forces upon their tissues.</p> - -<p><span class="pagenum"><a id="Page_274"></a>[274]</span></p> - -<p>The evolution of the intellectual and moral nature which -a higher animal really possesses from the sort of a nature -which the real activities of the protozoa manifest, is far -less difficult to explain.</p> - -<p>In so far as the higher animal is a collection of original -tendencies to respond to physical events without and within -the body, subject to modification by the laws of exercise -and effect and by these alone, and in so far as the protozoan -is already possessed of a well-defined repertory of responses -connected with physical events without and within the -body in substantially the manner of the higher animal’s -original tendencies, the problems of the evolution of behavior -are definite and in the way of solution.</p> - -<p>The previous sections gave reason for the belief that the -higher animals, including man, manifest no behavior -beyond expectation from the laws of instinct, exercise and -effect. The human mind was seen to do no more than -connect in accord with original bonds, use and disuse, and -the satisfaction and discomfort resulting to the neurones. -The work of Jennings has shown that the protozoa already -possess full-fledged instincts, homologous with the instincts -of man. They too may have specialized receptors, an -action-system with a well-defined repertory and a connecting -system or means of influencing the bonds between the -stimuli received and the motor reactions made. The difficulties -of tracing the possible development of a super-man -from an infra-animal thus disappear.</p> - -<p>There is, of course, an abundance of <i>bona fide</i> difficulty -in discovering the unlearned behavior of each group of -animals and in tracing, throughout the animal series, -changes in the physical events to which animals are sensitive -so that to each a different response may be attached, -changes in the movements of which animals are capable,<span class="pagenum"><a id="Page_275"></a>[275]</span> -and changes in the bonds by which particular movements -follow particular physical events. To find when and how -animals whose natures remained nearly or quite unchanged -by the satisfying and annoying effects of their behavior, -gave birth to animals that could learn, is perhaps a still -harder task. But these tasks concern problems that are -intelligible matters of fact. They do not require a student -to get out of matter something defined as beyond matter, -or to get volition out of tropisms, or to get ideas of space -and time out of swimming and sleeping.</p> - -<p>The evolution of the sensitivities and of the action-systems -of animals has already been subjected to matter-of-fact -study by naturalists. The evolution of the connection-system -will soon be. Each reflex, instinct or capacity, -each bond between a given situation presented to a given -physiological state and a given response, has its ancestral -tree. Scratching at an irritated spot on the skin -is older than arms. Following an object that is moving -slowly does not have to be explained separately, as a -‘chance’ variation in dogs, sheep and babies. The mechanical -trades of man are related to the miscellaneous -manipulations of the apes. Little as we know of the connection-systems -possessed by animals, we know enough -to be sure that a bond between situation and response -has ancestors and children as truly as does any bodily -organ. Professor Whitman a decade ago showed the possibility -of phylogenetic investigation of instinctive connections -in a study which should be a stimulus and model -for many others. In place of any further general account -of the study of the phylogeny of the connection-system, -I shall quote from his account of the concrete phylogeny -of the instinct of incubation.</p> - -<p><span class="pagenum"><a id="Page_276"></a>[276]</span></p> - -<div class="blockquote"> - -<p class="center">“<i>b. The Incubation Instinct</i></p> - -<p>1. <i>Meaning to be Sought in Phyletic Roots.</i>—It seems -quite natural to think of incubation merely as a means of -providing the heat needed for the development of the egg, -and to assume that the need was felt before the means -was found to meet it. Birds and eggs are thus presupposed, -and as the birds could not have foreseen the need, they -could not have hit upon the means except by accident. -Then, what an infinite amount of chancing must have -followed before the first ‘cuddling’ became a habit, and -the habit a perfect instinct! We are driven to such preposterous -extremities as the result of taking a purely casual -feature to start with. Incubation supplies the needed heat, -but that is an incidental utility that has nothing to do with -the nature and origin of the instinct. It enables us to see -how natural selection has added some minor adjustments, -but explains nothing more. For the real meaning of the -instinct we must look to its phyletic roots.</p> - -<p>If we go back to animals standing near the remote ancestors -of birds, to the amphibia and fishes, we find the same -instinct stripped of its later disguises. Here one or both -parents simply remain over or near the eggs and keep a -watchful guard against enemies. Sometimes the movements -of the parent serve to keep the eggs supplied with -fresh water, but aëration is not the purpose for which the -instinct exists.</p> - -<p>2. <i>Means Rest and Incidental Protection to Offspring.</i>—The -instinct is a part of the reproductive cycle of activities, -and always holds the same relation in all forms that exhibit -it, whether high or low. It follows the production of eggs, -or young, and means primarily, as I believe, rest, with<span class="pagenum"><a id="Page_277"></a>[277]</span> -incidental protection to offspring. That meaning is always -manifest, no less in worms, molluscs, crustacea, spiders -and insects, than in fishes, amphibia, reptiles and birds. -The instinct makes no distinction between eggs and young, -and that is true all along the line up to birds, which extend -the same blind instinct to one as to the other.</p> - -<p>3. <i>Essential Elements of the Instinct.</i>—Every essential -element in the instinct of incubation was present long -before the birds and eggs arrived. These elements are: -(1) the disposition to remain with or over the eggs; (2) the -disposition to resist and drive away enemies; and (3) periodicity. -The birds brought all these elements along in -their congenital equipment, and added a few minor adaptations, -such as cutting the period of incubation to the -need of normal development, and thus avoiding indefinite -waste of time in case of sterile or abortive eggs.</p> - -<p>(1) <i>Disposition to Remain over the Eggs.</i>—The disposition -to remain over the eggs is certainly very old, and is -probably bound up with the physiological necessity for rest -after a series of activities tending to exhaust the whole system. -If this suggestion seems far-fetched, when thinking -of birds, it will seem less so as we go back to simpler conditions, -as we find them among some of the lower invertebrate -forms, which are relatively very inactive and predisposed -to remain quiet until impelled by hunger to move. -Here we find animals remaining over their eggs, and thus -shielding them from harm, from sheer inability or indisposition -to move. That is the case with certain molluscs -(<i>Crepidula</i>), the habits and development of which have been -recently studied by Professor Conklin. Here full protection -to offspring is afforded without any exertion on the part -of the parent, in a strictly passive way that excludes even -any instinctive care. In <i>Clepsine</i> there is a manifest<span class="pagenum"><a id="Page_278"></a>[278]</span> -unwillingness to leave the eggs, showing that the disposition -to remain over them is instinctive. If we start with forms -of similar sedentary mode of life, it is easy to see that remaining -over the eggs would be the most likely thing to -happen, even if no instinctive regard for them existed. -The protection afforded would, however, be quite sufficient -to insure the development of the instinct, natural selection -favoring those individuals which kept their position unchanged -long enough for the eggs to hatch.”<a id="FNanchor_45" href="#Footnote_45" class="fnanchor">[45]</a></p> - -<p>Professor Whitman proceeds to study the ‘Disposition -to Resist Enemies’ and the ‘Periodicity’ in the same genetic -way.</p> - -</div> - -<p>The most important of all original abilities is the ability -to learn. It, like other capacities, has evolved. The -animal series shows a development from animals whose -connection-system suffers little or no permanent modification -by experience to animals whose connections are in -large measure created by use and disuse, satisfaction and -discomfort.</p> - -<p>Some of this development can be explained without recourse -to differences in mere power to learn, by the fact -that the latter animals are given greater stimuli to or rewards -for learning. But part of it is due to differences in -sheer ability to learn, that is, in the power of equally -satisfying conditions to strengthen or of equally annoying -conditions to weaken bonds in the animals’ connection-systems. -This may be seen from the following simple and -partial case:—</p> - -<p>Call 1 and 2 two animals.</p> - -<p>Call C₁ and C₂ the internal conditions of the two animals<span class="pagenum"><a id="Page_279"></a>[279]</span> -except for their connection-systems, each being the average -condition of the animal in question.</p> - -<p>Call S₁ and S₂ two external states of affairs, each being -near the indifference point for the animal in question,—that -is, being one which the animal does little to either -avoid or secure.</p> - -<p>Call G₁ and G₂ two responses which result in O₁ and O₂ the -<i>optima</i> or most satisfying state of affairs for 1 and 2.</p> - -<p>Call I₁ and I₂ two responses which result in the continuation -of S₁ and S₂.</p> - -<p>The only responses possible for 1 are G₁ and I₁.</p> - -<p>The only responses possible for 2 are G₂ and I₂.</p> - -<p>Animal 1 upon the recurrence of S₁ and C₁ is little or no -more likely to respond by G₁ than he was before.</p> - -<p>Animal 2 upon the recurrence of S₂ and C₂ is far more -likely to respond by G₂ than he was before.</p> - -<p>The fact thus outlined might conceivably be due to an -intrinsic inequality between O₁ and O₂, the power of equally -satisfying <i>optima</i> to influence, their antecedents being identical. -This is not the case in the evolution of learning, -however. For even if, instead of O₂, we had only a moderately -satisfying state of affairs, such as the company of -other chicks to (2) a 15-day-old chick, while O₁ was the -optimum of darkness, dampness, coolness, etc., for (1) an -earthworm, 2 would learn far, far more rapidly than 1.</p> - -<p>The fact is due, of course, to the unequal power of equally -satisfying conditions to influence their antecedents. The -same argument holds good for the influence of discomfort.</p> - -<p>The ability to learn,—that is, the possession of a connection-system -subject to the laws of exercise and effect,—has -been found in animals as ‘low’ as the starfish and -perhaps in the protozoa. It is hard to tell whether the -changed responses observed in Stentor by Jennings and in<span class="pagenum"><a id="Page_280"></a>[280]</span> -Paramecium by Stevenson Smith are easily forgotten learnings -or long retained excitabilities. Sooner or later clear -learning appears, and then, from crabs to fish and turtle, -from these to various birds and mammals, from these to -monkeys, and from these to man, a fairly certain increase -in sheer ability to learn, in the potency of a supposedly -constant degree of satisfyingness or annoyingness to influence -the connection preceding it, can be assumed. We -cannot, of course, define just what we mean by equal satisfyingness -to a mouse and a man, but the argument is substantially -the same as that whereby we assume that the -gifted boy has more sheer ability to learn than the idiot, so -that if the two made the same response to the same situation -and were equally satisfied thereby, the former would -form the habit more firmly.</p> - -<p>We may, therefore, expect that when knowledge of the -structure and behavior of the neurones comprising the connection-systems -of animals (or of the neurones’ predecessors -in this function) progresses far enough to inform us of just -what happens when a connection is made stronger or weaker -and of just what effects satisfying and annoying states of -affairs exert upon the connection-system (and in particular -upon the connections most recently in activity) the ability -to learn will show as true an evolution as the ability to sneeze, -oppose the thumb, or clasp an object touched by the hand.</p> - -<p>If my analysis is true, the evolution of behavior is a rather -simple matter. Formally the crab, fish, turtle, dog, cat, -monkey and baby have very similar intellects and characters. -All are systems of connections subject to change by -the law of exercise and effect. The differences are: first, in -the concrete particular connections, in <i>what</i> stimulates the -animal to response, <i>what</i> responses it makes, <i>which</i> stimulus -connects with <i>which</i> response, and second, in the degree of<span class="pagenum"><a id="Page_281"></a>[281]</span> -ability to learn—in the amount of influence of a given degree -of satisfyingness or annoyingness upon the connection -that produced it.</p> - -<p>The peculiarly human features of intellect and character, -responses to elements and symbols, are the results of: -first, a receiving system that is easily stimulated by the -external world bit by bit (as by focalized vision and touch -with the moving hand) as well as in totals composed of various -aggregates of these bits; second, of an action-system of -great versatility (as in facial expression, articulation, and -the hands’ movements); and third, of a connection-system -that includes the connections roughly denoted by babbling, -manipulation, curiosity, and satisfaction at activity, bodily -or mental, for its own sake; that is capable of working in -great detail, singling out elements of situations and parts -of responses; and that allows satisfying and annoying states -of affairs to exert great influence on their antecedent connections. -Because he learns fast and learns much, in the -animal way, man seems to learn by intuitions of his own.</p> - -<hr class="chap x-ebookmaker-drop"> - -<div class="chapter"> - -<p><span class="pagenum"><a id="Page_282"></a>[282]</span></p> - -<h2 class="nobreak" id="CHAPTER_VII">CHAPTER VII<br> -<span class="smcap">The Evolution of the Human Intellect</span><a id="FNanchor_46" href="#Footnote_46" class="fnanchor">[46]</a></h2> - -</div> - -<p>To the intelligent man with an interest in human nature -it must often appear strange that so much of the energy of -the scientific world has been spent on the study of the body -and so little on the study of the mind. ‘The greatest thing -in man is mind,’ he might say, ‘yet the least studied.’ Especially -remarkable seems the rarity of efforts to trace the -evolution of the human intellect from that of the lower animals. -Since Darwin’s discovery, the beasts of the field, -the fowl of the air and the fish of the sea have been examined -with infinite pains by hundreds of workers in the -effort to trace our physical genealogy, and with consummate -success; yet few and far between have been the efforts to -find the origins of intellect and trace its progress up to human -faculty. And none of them has achieved any secure -success.</p> - -<p>It may be premature to try again, but a somewhat extended -series of studies of the intelligent behavior of fishes, -reptiles, birds and mammals, including the monkeys, which -it has been my lot to carry out during the last five years, has -brought results which seem to throw light on the problem -and to suggest its solution.</p> - -<p>Experiments have been made on fishes, reptiles, birds and -various mammals, notably dogs, cats, mice and monkeys, -to see how they learned to do certain simple things in order<span class="pagenum"><a id="Page_283"></a>[283]</span> -to get food. All these animals manifest fundamentally the -same sort of intellectual life. Their learning is after the -same general type. What that type is can be seen best from -a concrete instance. A monkey was kept in a large cage. -Into the cage was put a box, the door of which was held -closed by a wire fastened to a nail which was inserted in a -hole in the top of the box. If the nail was pulled up out of -the hole, the door could be pulled open. In this box was a -piece of banana. The monkey, attracted by the new object, -came down from the top of the cage and fussed over the box. -He pulled at the wire, at the door, and at the bars in the -front of the box. He pushed the box about and tipped it up -and down. He played with the nail and finally pulled it out. -When he happened to pull the door again, of course it opened. -He reached in and got the food inside. It had taken him -36 minutes to get in. Another piece of food being put in -and the door closed, the occurrences of the first trial were -repeated, but there was less of the profitless pulling and tipping. -He got in this time in 2 minutes and 20 seconds. -With repeated trials the animal finally came to drop entirely -the profitless acts and to take the nail out and open -the door as soon as the box was put in his cage. He had, -we should say, learned to get in.</p> - -<p>The process involved in the learning was evidently a -process of selection. The animal is confronted by a state -of affairs or, as we may call it, a ‘situation.’ He reacts in -the way that he is moved by his innate nature or previous -training to do, by a number of acts. These acts include -the particular act that is appropriate and he succeeds. In -later trials the impulse to this one act is more and more -stamped in, this one act is more and more associated with -that situation, is selected from amongst the others by reason -of the pleasure it brings the animal. The profitless acts<span class="pagenum"><a id="Page_284"></a>[284]</span> -are stamped out; the impulses to perform them in that -situation are weakened by reason of the positive discomfort -or the absence of pleasure resulting from them. So the -animal finally performs in that situation only the fitting act.</p> - -<p>Here we have the simplest and at the same time the most -widespread sort of intellect or learning in the world. There -is no reasoning, no process of inference or comparison; -there is no thinking about things, no putting two and two -together; there are no ideas—the animal does not think -of the box or of the food or of the act he is to perform. He -simply comes after the learning to feel like doing a certain -thing under certain circumstances which before the learning -he did not feel like doing. Human beings are accustomed -to think of intellect as the power of having and controlling -ideas and of ability to learn as synonymous with ability to -have ideas. But learning by having ideas is really one of -the rare and isolated events in nature. There may be a -few scattered ideas possessed by the higher animals, but the -common form of intelligence with them, their habitual -method of learning, is not by the acquisition of ideas, but -by the selection of impulses.</p> - -<p>Indeed this same type of learning is found in man. When -we learn to drive a golf ball or play tennis or billiards, when -we learn to tell the price of tea by tasting it or to strike a -certain note exactly with the voice, we do not learn in the -main by virtue of any ideas that are explained to us, by -any inferences that we reason out. We learn by the gradual -selection of the appropriate act or judgment, by its -association with the circumstances or situation requiring -it, in just the way that the animals do.</p> - -<p>From the lowest animals of which we can affirm intelligence -up to man this type of intellect is found. With -it there are in the mammals obscure traces of the ideas<span class="pagenum"><a id="Page_285"></a>[285]</span> -which come in the mental life of man to outweigh and hide it. -But it is the basal fact. As we follow the development -of animals in time, we find the capacity to select impulses -growing. We find the associations thus made between -situation and act growing in number, being formed more -quickly, lasting longer and becoming more complex and -more delicate. The fish can learn to go to certain places, to -take certain paths, to bite at certain things and refuse others, -but not much more. It is an arduous proceeding for him -to learn to get out of a small pen by swimming up through -a hole in a screen. The monkey can learn to do all sorts -of things. It is a comparatively short and easy task for -him to learn to get into a box by unhooking a hook, pushing -a bar around and pulling out a plug. He learns quickly -to climb down to a certain place when he sees a letter T -on a card and to stay still when he sees a K. He performs -the proper acts nearly as well after 50 days as he did when -they were fresh in his mind.</p> - -<p>This growth in the number, speed of formation, permanence, -delicacy and complexity of associations possible for -an animal reaches its acme in the case of man. Even if we -leave out of question the power of reasoning, the possession -of a multitude of ideas and abstractions and the power of -control over impulses, purposive action, man is still the -intellectual leader of the animal kingdom by virtue of the -superior development in him of the power of forming associations -between situations or sense-impressions and acts, -by virtue of the degree to which the mere learning by -selection possessed by all intelligent animals has advanced. -In man the type of intellect common to the animal kingdom -finds its fullest development, and with it is combined the -hitherto nonexistent power of thinking about things and -rationally directing action in accord with thought.</p> - -<p><span class="pagenum"><a id="Page_286"></a>[286]</span></p> - -<p>Indeed it may be that this very reason, self-consciousness -and self-control which seem to sever human intellect so -sharply from that of all other animals are really but secondary -results of the tremendous increase in the number, delicacy -and complexity of associations which the human animal -can form. It may be that the evolution of intellect -has no breaks, that its progress is continuous from its -first appearance to its present condition in adult civilized -human beings. If we could prove that what we call ideational -life and reasoning were not new and unexplainable -species of intellectual life but only the natural consequences -of an increase in the number, delicacy, and complexity of -associations of the general animal sort, we should have -made out an evolution of mind comparable to the evolution -of living forms.</p> - -<p>In 1890 William James wrote, “The more sincerely one -seeks to trace the actual course of psychogenesis, the -steps by which as a race we may have come by the peculiar -mental attributes which we possess, the more clearly one -perceives ‘the slowly gathering twilight close in utter -dark.’” Can we perhaps prove him a false prophet? Let -us first see if there be any evidence that makes it probable -that in some way or another the mere extension of the -animal type of intellect has produced the human sort. If -we do, let us proceed to seek a possible account of <i>how</i> this -might have happened, and finally to examine any evidence -that shows this possible ‘how’ to have been the real way -in which human reason has evolved.</p> - -<p>It has already been shown that in the animal kingdom -there is, as we pass from the early vertebrates down to man, -a progress in the evolution of the general associative process -which practically equals animal intellect, that this progress -continues as we pass from the monkeys to man. Such a<span class="pagenum"><a id="Page_287"></a>[287]</span> -progress is a real fact; it does exist as a possible <i>vera causa</i>; -it is thus at all events better than some imaginary cause -of the origin of human intellect, the very existence of -which is in doubt. In a similar manner we know that the -neurones, which compose the brain and the connections -between which are the physiological parallels of the habits -that animals form, show, as we pass down through the -vertebrate series, an evolution along lines of increased delicacy -and complexity. That an animal associates a certain -act with a certain felt situation means that he forms or -strengthens connections between certain cells. The increase -in number, delicacy and complexity of cell structures -is thus the basis for an increase in the number, delicacy -and complexity of associations. Now the evolution noted -in cell structures affects man as well as the other vertebrates. -He stands at the head of the scale in that respect as well. -May not this obvious supremacy in the animal type of intellect -and in the adaption of his brain to it be at the bottom -of his supremacy in being the sole possessor of reasoning?</p> - -<p>This question becomes more pressing if we realize that -we must have some sort of brain correlate for ideational -life and reasoning. Some sort of difference in processes in -the brain must be at the basis of the mental differences between -man and the lower animals, we should all admit. And -it would seem wise to look for that difference amongst differences -which really do or at least may exist. Now the most -likely brain difference between man and the lower animals for -our purpose, to my mind indeed the only likely one, is just this -difference in the fineness of organization of the cell structures. -If we could show with any degree of probability -how it might account for the presence of ideas and of reasoning, -we should at least have the satisfaction of dealing with -a cause actually known to exist.</p> - -<p><span class="pagenum"><a id="Page_288"></a>[288]</span></p> - -<p>The next important fact is that the intellect of the infant -six months to a year old is of the animal sort, that ideational -and reasoning life are not present in his case, that the only -obvious intellectual difference between him and a monkey is -in the quantity and quality of the associations formed. -In the evolution of the infant’s mind to its adult condition -we have the actual transition within an individual from the -animal to the human type of intellect. If we look at the -infant and ask what is in him to make in the future a thinker -and reasoner, we must answer either by invoking some mysterious -capacity, the presence of which we cannot demonstrate, -or by taking the difference we actually do find. That is -the difference in the quality and quantity of associations of -the animal sort. Even if we could never see how it came to -cause the future intellectual life, it would seem wiser to believe -that it did than to resort to faith in mysteries. Surely there -is enough evidence to make it worth while to ask our second -question, “How might this difference cause the life of ideas -and reasoning?”</p> - -<p>To answer this question fully would involve a most intricate -treatment of the whole intellectual life of man, a -treatment which cannot be attempted without reliance on -technical terms and psychological formulas. A fairly -comprehensible account of the general features of such an -answer can, however, be given. The essential thing about -the thinking of the animals is that they feel things in gross. -The kitten who learned to respond differently to the signals, -“I must feed those cats” and “I will not feed them,” felt -each signal as a vague total, including the tone, the movements -of my head, etc. It did not have an idea of the sound -of <i>I</i>, another of the sound of <i>must</i>, another of the sound -<i>feed</i>, etc. It did not turn the complex impression into a set -of elements, but felt it, as I have said, in gross. The dog<span class="pagenum"><a id="Page_289"></a>[289]</span> -that learned to get out of a box by pulling a loop of wire -did not feel the parts of the box separately, the bolt as a -definite circle of a certain size, did not feel his act as a sum -of certain particular movements. The monkey who learned -to know the letter K from the letter Y did not feel the separate -lines of the letter, have definite ideas of the parts. -He just felt one way when he saw one total impression and -another way when he saw another.</p> - -<p>Strictly human thinking, on the contrary, has as its essential -characteristic the breaking up of gross total situations -into feelings of particular facts. When in the presence -of ten jumping tigers we not only feel like running, but also -feel the number of tigers, their color, their size, etc. When, -instead of merely associating some act with some situation -in the animal way, we think the situation out, we have a -set of particular feelings of its elements. In some cases, it -is true, we remain restricted to the animal sort of feelings. -The sense impressions of suffocation, of the feeling of a -new style of clothes, of the pressure of 10 feet of water above -us, of malaise, of nausea and such like remain for most of us -vague total feelings to which we react and which we feel -most acutely but which do not take the form of definite -ideas that we can isolate or combine or compare. Such -feelings we say are not parts of our real intellectual life. -They <i>are</i> parts of our intellectual life if we mean by it the -mental life concerned in learning, but they are not if we -mean by it the life of reasoning.</p> - -<p>Can we now see how the vague gross feelings of the animal -sort might turn into the well-defined particular ideas of the -human sort, by the aid of a multitude of delicate associations?</p> - -<p>It seems to be a general law of mind that any mental -element which occurs with a number of different mental -elements, appears, that is, in a number of different combinations,<span class="pagenum"><a id="Page_290"></a>[290]</span> -tends to thereby acquire an independent life -of its own. We show children six lines, six dots, six peas, -six pieces of paper, etc., and thus create the definite feeling -of sixness. Out of the gross feelings of a certain number of -lines, of dots, etc., we evolve the definite elementary feeling -of sixness by making the ‘six’ aspect of the situations -appear in a number of different connections. We learn to -feel whiteness as a definite idea by seeing white paper, white -cloth, white eggs, white plates, etc. We learn to feel -the meaning of <i>but</i> or <i>in</i> or <i>notwithstanding</i> by feeling the -meanings of many total phrases containing each of them. -Now in this general law by which different associates for the -same elementary process elevate it out of its position as -an undifferentiated fragment of a gross total feeling, we -have, I think, the manner in which the vague feelings of -the nine-months-old infant become the definite ideas of -the five-year-old boy, the manner in which in the race -the animal mind has evolved into the human, and the explanation -of the service performed by the increase in the -delicacy of structure of the human brain and the consequent -increase in the number of associations.</p> - -<p>The bottle to the six-months-old infant is a vague sense-impression -which the infant does not think about or indeed -in the common meanings of the words perceive or remember -or imagine. Its presence does not arouse ideas, but -action. It is not to him a thing so big, or so shaped, or -so heavy, but is just a vaguely sizable thing to be reached -for, grabbed and sucked. Like the lower animals, with the -exception that as he grows a little older he reacts in very -many more ways, the child feels things in gross in a way -to lead to direct reactions. Vague sense-impressions and -impulses make up his mental life. The bottle, which to a -dog would be a thing to smell at and paw, to a kitten a<span class="pagenum"><a id="Page_291"></a>[291]</span> -thing to smell at and perhaps worry, is to the child a little -later a thing to grab and suck and turn over and drop and -pick up and pull at and finger and rub against its toes and -so on. The sight of the bottle thus becomes associated -with many different reactions, and thus by our general law -tends to gain a position independent of any of them, to -evolve from the condition of being a portion of the cycles -see-grab, see-drop, see-turn over, etc., to the condition of -being a definite idea.</p> - -<p>The increased delicacy and complexity of the cell -structures in the human brain give the possibility of very -small parts of the brain-processes forming different connections, -allow the brain to work in very great detail, provide -processes ready to be turned into definite ideas. The great -number of associations which the human being forms -furnish the means by which this last event is consummated. -The infant’s vague feelings of total situations are by virtue -of the detailed working of his brain all ready to split up -into parts, and his general activity and curiosity provide -the multitude of different connections which allow them to -do so. The dog, on the other hand, has few or no ideas -because his brain acts in coarse fashion and because there -are few connections with each single process.</p> - -<p>When once the mind begins to function by having definite -ideas, all the phenomena of reasoning soon appear. -The transition from one idea to another is the feeling of -their relationship, of similarity or difference or whatever -it may be. As soon as we find any words or other symbols -to express such a feeling, or to express our idea of an action -or condition, we have explicit judgments. Observation -of any child will show us that the mind cannot rest in a condition -where it has a large body of ideas without comparing -them and thinking about them. The ideas carry within<span class="pagenum"><a id="Page_292"></a>[292]</span> -them the forces that make abstractions, feelings of similarity, -judgments and other characteristics of reasoning.</p> - -<p>In children two and three years of age we find all these -elements of reasoning present and functioning. The product -of children’s reasoning is often irrational, but the processes -are all there. The following instances from a collection -of children’s sayings by Mr. H. W. Brown show children -making inductions and deductions after the same general -fashion as adults:—</p> - -<div class="blockquote"> - -<p>(2 yrs.) T. pulled the hairs on his father’s wrist. Father. -“Don’t, T., you hurt papa!” T. “It didn’t hurt grandpa.”</p> - -<p>(2 yrs. 5 mos.) M. said, “Gracie can’t walk, she wears little -bits of shoes; if she had mine, she could walk. When I get some -new ones, I’m going to give her these, so she can walk.”</p> - -<p>(2 yrs. 9 mos.) He usually has a nap in the forenoon, but -Friday he did not seem sleepy, so his mother did not put him to -bed. Before long he began to say, “Bolly’s sleepy; mamma put -him in the crib!” This he said very pleasantly at first; but, as -she paid no attention to him, he said, “Bolly cry, then mamma -will.” And he sat down on the floor and roared.</p> - -<p>(3 yrs.) It was between five and six in the afternoon; the -mother was getting the baby asleep. J. had no one to play with. -He kept saying, “I wish R. would come home; mamma, put -baby to bed, so R. will come home.” I usually get home about -six, and as the baby is put to bed about half-past five, he had -associated the one with the other.</p> - -<p>(3 yrs.) W. likes to play with oil paints. Two days ago -my father told W. he must not touch the paints any more, for -he was too small. This morning W. said, “When my papa is a -very old man, and when I am a big man and don’t need any -papa, then I can paint, can’t I, mamma?”</p> - -<p>(3 yrs.) G.’s aunt gave him ten cents. G. went out, but soon -came back saying, “Mamma, we will be rich now.” “Why so,<span class="pagenum"><a id="Page_293"></a>[293]</span> -G.?” “Because I planted my ten cents, and we will have lots of -ten cents growing.”</p> - -<p>(3 yrs.) B. climbed up into a large express wagon, and would -not get out. I helped him out, and it was not a minute before -he was back in the wagon. I said, “B., how are you going to get -out of there now?” He replied, “I can stay here till it gets little, -and then I can get out my own self.”</p> - -<p>(3 yrs.) F. is not allowed to go to the table to eat unless she -has her face and hands washed and her hair combed. The other -day she went to a lady visiting at her house and said, “Please -wash my face and hands and comb my hair; I am very hungry.”</p> - -<p>(3 yrs.) If C. is told not to touch a certain thing, that it will -bite him, he always asks if it has a mouth. The other day he -was examining a plant, to see if it had a mouth. He was told -not to break it, and he said, “Oh, it won’t bite, because I can’t -find any mouth.”</p> - -</div> - -<p>Nowhere in the animal kingdom do we find the psychological -elements of reasoning save where there is a mental -life made up of the definite feelings which I have called -‘ideas,’ but they spring up like magic as soon as we get in a -child a body of such ideas. If we have traced satisfactorily -the evolution of a life of ideas from the animal life of vague -sense-impressions and impulses, we may be reasonably sure -that no difficulty awaits us in following the life of ideas -in its course from the chaotic dream of early childhood to -the logical world-view of the adult scientist.</p> - -<p>In a very short time we have come a long way, from the -simple learning of the minnow or chick to the science and -logic of man. The general frame of mind which one acquires -from the study of animal behavior and of the mental development -of young children makes our hypothesis seem -vital and probable. If the facts did eventually corroborate -it, we should have an eminently simple genesis of human<span class="pagenum"><a id="Page_294"></a>[294]</span> -faculty, for we could put together the gist of our contention -in a few words. We should say:—</p> - -<p>“The function of intellect is to provide a means of modifying -our reactions to the circumstances of life, so that we -may secure pleasure, the symptom of welfare. Its general -law is that when in a certain situation an animal acts so -that pleasure results, that act is selected from all those performed -and associated with that situation, so that, when -the situation recurs, the act will be more likely to follow than -it was before; that on the contrary the acts which, when -performed in a certain situation, have brought discomfort, -tend to be dissociated from that situation. The intellectual -evolution of the race consists in an increase in the number, -delicacy, complexity, permanence and speed of formation -of such associations. In man this increase reaches such a -point that an apparently new type of mind results, which -conceals the real continuity of the process. This mental -evolution parallels the evolution of the cell structures of -the brain from few and simple and gross to many and -complex and delicate.”</p> - -<p>Nowhere more truly than in his mental capacities is man -a part of nature. His instincts, that is, his inborn tendencies -to feel and act in certain ways, show throughout marks of -kinship with the lower animals, especially with our nearest -relatives physically, the monkeys. His sense-powers show -no new creation. His intellect we have seen to be a -simple though extended variation from the general animal -sort. This again is presaged by the similar variation -in the case of the monkeys. Amongst the minds of animals -that of man leads, not as a demigod from another planet, -but as a king from the same race.</p> - -<hr class="chap x-ebookmaker-drop"> - -<div class="footnotes"> - -<div class="chapter"> - -<h2 class="nobreak" id="FOOTNOTES">FOOTNOTES</h2> - -</div> - -<div class="footnote"> - -<p><a id="Footnote_1" href="#FNanchor_1" class="label">[1]</a> ‘Animal Intelligence: An Experimental Study of the Associative Processes -in Animals’ (’98), ‘The Instinctive Reactions of Young Chicks’ (’99), -‘A Note on the Psychology of Fishes’ (’99), and ‘The Mental Life of the -Monkeys’ (’01). I have added a theoretical paper, ‘The Evolution of the -Human Intellect,’ which appeared in the <i>Popular Science Monthly</i> in 1901, -and which was a direct outgrowth of the experimental work. I am indebted -to the management of the <i>Psychological Review</i>, and that of the <i>American -Naturalist</i> and <i>Popular Science Monthly</i>, for permission to reprint the three -shorter papers.</p> - -</div> - -<div class="footnote"> - -<p><a id="Footnote_2" href="#FNanchor_2" class="label">[2]</a> Unless one assumes telepathic influences.</p> - -</div> - -<div class="footnote"> - -<p><a id="Footnote_3" href="#FNanchor_3" class="label">[3]</a> Reason in Common Sense, p. 154 ff.</p> - -</div> - -<div class="footnote"> - -<p><a id="Footnote_4" href="#FNanchor_4" class="label">[4]</a> This chapter originally appeared as Monograph Supplement No. 8 of -the Psychological Review.</p> - -</div> - -<div class="footnote"> - -<p><a id="Footnote_5" href="#FNanchor_5" class="label">[5]</a> I do not mean that scientists have been too credulous with regard to -spiritualism, but am referring to the cases where ten or twenty scientists -have been sent to observe some trick-performance by a spiritualistic ‘medium,’ -and have all been absolutely confident that they understood the secret -of its performance, <i>each of them giving a totally different explanation</i>.</p> - -</div> - -<div class="footnote"> - -<p><a id="Footnote_6" href="#FNanchor_6" class="label">[6]</a> The phrase ‘practically utter hunger’ has given rise to misunderstandings. -I have been accused of experimenting with starving or half-starved -animals, with animals brought to a state of fear and panic by hunger, and -the like!</p> - -<p>The desideratum is, of course, to have the motive as nearly as possible of -equal strength in each experiment with any one animal with any one act. -That is, the animal should be as hungry at the tenth or twentieth trial as at -the first. To attain this, the animal was given after each ‘success’ only -a very small bit of food as a reward (say, for a young cat, one quarter of a -cubic centimeter of fish or meat) and tested not too many times on any one -day. ‘Utter hunger’ means that no diminution in his appetite was noted -and that at the close of the experiment for the day he would still eat a hearty -meal. After the experiments for the day were done, the cats received -abundant food to maintain health, growth and spirits, but commonly somewhat -less than they would of their own accord have taken. No one of the -many visitors to the room mentioned anything extraordinary or distressful -in the animals’ condition. There were no signs of fear or panic.</p> - -<p>Possibly I was wrong in choosing the term ‘utter hunger’ to denote the -hunger of an animal in good, but not pampered, condition and without food -for fourteen hours. It is not sure, however, that the term ‘utter hunger’ -is inappropriate. The few reports made of experiments in going without -food seem to show that, in health, the feeling of hunger reaches its maximum -intensity very early. It is of course not at all the same thing as the complex -of discomforts produced by long-continued insufficiency of food. Hunger -is not at all a synonym for starvation.</p> - -</div> - -<div class="footnote"> - -<p><a id="Footnote_7" href="#FNanchor_7" class="label">[7]</a> The experiments now to be described were for the most part made in the -Psychological Laboratory of Columbia University during the year ’97-’98, -but a few of them were made in connection with a general preliminary -investigation of animal psychology undertaken at Harvard University in -the previous year.</p> - -</div> - -<div class="footnote"> - -<p><a id="Footnote_8" href="#FNanchor_8" class="label">[8]</a> No. 7 hit the string in his general struggling, apparently utterly without -design. He did not realize that the door was open till, two seconds after it -had fallen, he happened to look that way.</p> - -</div> - -<div class="footnote"> - -<p><a id="Footnote_9" href="#FNanchor_9" class="label">[9]</a> No. 6, in trying to crawl out at the top of the box, put its paw in above -the string. It fell down and thus pulled the string. It did not claw at it, -and it was 16 seconds before it noticed that the door was open. In all -the other times that it escaped the movement was made in the course of -promiscuous scrambling, never in anything like the same way that No. 2 -made it.</p> - -</div> - -<div class="footnote"> - -<p><a id="Footnote_10" href="#FNanchor_10" class="label">[10]</a> No. 3 did not go out until 12 seconds had elapsed after it had pulled the -string.</p> - -</div> - -<div class="footnote"> - -<p><a id="Footnote_11" href="#FNanchor_11" class="label">[11]</a> The back of the pen adjoined the elevator shaft, being separated from it -by a partition 33 inches high. No. 2 heard the elevator coming up and put -his paws up on the top of this partition so as to look over. In so doing he -knocked the fastening of the cord at that end and opened the door. He -did not turn to come out, and I shut the door again.</p> - -</div> - -<div class="footnote"> - -<p><a id="Footnote_12" href="#FNanchor_12" class="label">[12]</a> FF was a box 40 × 21 × 24 inches, the door of which could be opened -by putting the paw out between the bars to its right and pulling a loop which -hung 16 inches above the floor, 4 inches out from the box and 6 inches to -the right of the door.</p> - -</div> - -<div class="footnote"> - -<p><a id="Footnote_13" href="#FNanchor_13" class="label">[13]</a> KKK was box K with both bolts removed. All that had to be done -was to poke the paw out at one side of the door and press down a little bar of -wood.</p> - -</div> - -<div class="footnote"> - -<p><a id="Footnote_14" href="#FNanchor_14" class="label">[14]</a> The cats and chick were left in for two minutes at each trial, the dogs -for from one to one and a half minutes.</p> - -</div> - -<div class="footnote"> - -<p><a id="Footnote_15" href="#FNanchor_15" class="label">[15]</a> One result of the application of experimental method to the study of -the intellect of animals was the distinction of learning by the selection of -impulses or acts from learning by the selection of ideas. The usual method -of learning in the case of animals other than man was shown by the studies -reprinted in this volume to be the direct selection, in a certain situation, of -a desirable response and its association with that situation, not the indirect -selection of such a response by the selection of some <i>idea</i> which then of -itself produced the response. The animals did not usually behave as if they -<i>thought of</i> getting freedom or food in a certain way and were thereby moved -to do so, but as if the stimulus in question made immediate connection with -the response itself or an intimately associated impulse.</p> - -<p>The experiments had in this respect both a negative or destructive and a -positive or constructive meaning. On the one hand, they showed that animal -learning was not homologous with human association of ideas; that animal -learning was not human learning <i>minus</i> abstract and conceptual thought, -but was on a still ‘lower’ level. On the other hand, the first positive evidence -that animals could, under certain circumstances, learn, as man so -commonly does, by the indirect connection of a response with a situation -through some non-sensory relic or representative of the latter, came from my -experiments.</p> - -<p>It was perhaps natural that the more exciting denial of habitual learning -by ideas should have attracted more attention than the somewhat tedious -experiments to prove that under certain conditions they could so learn. -At all events, a perverse tradition seems to have grown up to the effect that -I denied the possibility of animals having images or learning in any case by -representative thinking.</p> - -<p>There is some excuse for this tradition in the fact that whereas the proof -that the habitual learning of these dogs and cats did not require ‘ideas’ -is clear and emphatic, my evidence that certain features of their behavior -<i>did</i> require ‘ideas’ is complicated and imperfect.</p> - -<p>The fact seems to be that a ‘free idea’ comes in the animals or in man -only as a result of a somewhat elaborate process of analysis or extraction from -a gross total sensory process. The primary level or grade of experience, -common to animals and little babies, comprises states of mind such as an -adult man gets if lost in anger, fear, suffocation, dyspepsia, looking at a -panorama of unknown objects with head upside down, smelling the mixture -of odors of a soap factory, driving a golf ball, dashing to the net in a game of -tennis, warding off a blow, or swimming under water. For a man to get a -distinct controllable percept of approaching asthma, of a carpet loom seen -upside down, or of a successful ‘carry through,’ or ‘smash’ or ‘lob,’ -so that one knows just what one is experiencing or doing, and can recall -just what one experienced or did, requires further experience of the element -in question—contemplation of it in isolation or dealings with it in many varied -connections. So for a cat to get a distinct controllable percept of a loop, -or of its own clawing or nosing or pulling, it must have the capacity to analyze -such elements out of the total gross complexes in which they inhere, -and also certain means or stimuli to such analysis.</p> - -<p>This capacity or tendency the cats and dogs do, in my opinion, possess, -though in a far less degree than the average child. They also suffer from -lack of stimuli to the exercise of the capacity. Their confinement, for the -most part, to the direct sensory experience of things and acts, is due in part -to the weakness of the capacity or tendency of their neurones to act in great -detail, and in part to the lack of such stimuli as visual exploration of things -in detail, manual manipulation of the same thing in many ways, and the identification -of elements of objects and acts by language. They get few free -ideas because they are less ready than man to get them under the same conditions -and because their instinctive behavior and social environment offer -conditions that are less favorable. The task of getting an animal to have -some free ideational representative of a red loop or of pushing up a button -with the nose may be compared with that of getting a very stupid boy to -have a free ideational representative of acceleration, or of the act of sounding -<i>th</i>. The difference between them and man which is so emphasized in -the text, though real and of enormous practical importance, is thus not at -all a mysterious gap or trackless desert. We can see our way from animal -to human learning.</p> - -</div> - -<div class="footnote"> - -<p><a id="Footnote_16" href="#FNanchor_16" class="label">[16]</a> A man may learn to swim from the general feeling, “I want to be able to -swim.” While learning, he may think of this desire, of the difficulties of the -motion, of the instruction given him, or of anything which may turn up in -his mind. This is all extraneous and is not concerned in the acquisition of -the association. Nothing like it, of course, goes on in the animal’s mind. -Imagine a man thrown into the water repeatedly, and gradually floundering -to the shore in better and better style until finally, when thrown in, he swims -off perfectly, and deprive the man of all extraneous feelings, and you have -an approximate homologue of the process in animals. He feels discomfort, -certain impulses to flounder around, some of which are the right ones to -move his body to the shore. The pleasure which follows stamps in these, -and gradually the proper movements are made immediately on feeling the -sense-impression of surrounding water.</p> - -</div> - -<div class="footnote"> - -<p><a id="Footnote_17" href="#FNanchor_17" class="label">[17]</a> See 10 in A, 3 in A, 10 in D; 10 in C, 4 in C, 3 in C; 6, 2, 5, 4 in E; 4 in -F; 10 in H, 3 in H; 3, 4, 5, in I; 4 in G, 3 in G; 3 in K; 10 in L; dog 1 in N -and CC; dog 1 in G and O.</p> - -</div> - -<div class="footnote"> - -<p><a id="Footnote_18" href="#FNanchor_18" class="label">[18]</a> This chapter appeared originally in the <i>Psychological Review</i>, Vol. VI, -No. 3.</p> - -</div> - -<div class="footnote"> - -<p><a id="Footnote_19" href="#FNanchor_19" class="label">[19]</a> This double rating is necessary because of the fact that the chick often -gives several distinct pecks in a single reaction. The ‘times reacted to’ -mean the number of different times that the chicks noticed the color.</p> - -</div> - -<div class="footnote"> - -<p><a id="Footnote_20" href="#FNanchor_20" class="label">[20]</a> The crude experiments reported in this and the preceding paragraphs -were not made to test the presence of color vision proper, that is, of differentiation -of two colors of the same brightness, but only to ascertain how -chicks reacted to ordinary colored objects. It was, however, almost certain -from the relative frequency of the reactions that the intensity factor was not -the cause of the response. For example, if it had been, black on white and -yellow on black should have been pecked at oftener.</p> - -</div> - -<div class="footnote"> - -<p><a id="Footnote_21" href="#FNanchor_21" class="label">[21]</a> This chapter appeared originally in the <i>American Naturalist</i>, Vol. XXXIII, -No. 396.</p> - -</div> - -<div class="footnote"> - -<p><a id="Footnote_22" href="#FNanchor_22" class="label">[22]</a> This chapter appeared originally as Monograph Supplement No. 15 to -the <i>Psychological Review</i>.</p> - -</div> - -<div class="footnote"> - -<p><a id="Footnote_23" href="#FNanchor_23" class="label">[23]</a> <a href="#Page_20">Pp. 20 to 155</a> of this volume.</p> - -</div> - -<div class="footnote"> - -<p><a id="Footnote_24" href="#FNanchor_24" class="label">[24]</a> <i>American Journal of Psychology</i>, Vol. X, pp. 256-279; Vol. XI, pp. 80-100, -131-165; Vol. XII, pp. 206-239.</p> - -</div> - -<div class="footnote"> - -<p><a id="Footnote_25" href="#FNanchor_25" class="label">[25]</a> Practically a memory trial of CC, done January 21, 1900.</p> - -</div> - -<div class="footnote"> - -<p><a id="Footnote_26" href="#FNanchor_26" class="label">[26]</a> Did it by pulling door and thus shaking lever.</p> - -</div> - -<div class="footnote"> - -<p><a id="Footnote_27" href="#FNanchor_27" class="label">[27]</a> Practically a memory trial of SS.</p> - -</div> - -<div class="footnote"> - -<p><a id="Footnote_28" href="#FNanchor_28" class="label">[28]</a> Did it by pulling door and biting wire.</p> - -</div> - -<div class="footnote"> - -<p><a id="Footnote_29" href="#FNanchor_29" class="label">[29]</a> This, I regret, was not done [E. L. T., 1911].</p> - -</div> - -<div class="footnote"> - -<p><a id="Footnote_30" href="#FNanchor_30" class="label">[30]</a> The acts and the number of chances to see me do each and the results -were as follows; details can be found on the table on <a href="#Page_226">page 226</a>. F = failed -after tuition.</p> - -<table> - <tr> - <td>No. 1.—</td> - <td>MM</td> - <td class="tdr">21</td> - <td>F</td> - </tr> - <tr> - <td></td> - <td>Theta</td> - <td class="tdr">5</td> - <td>F</td> - </tr> - <tr> - <td></td> - <td>QQ</td> - <td class="tdr">10</td> - <td>F</td> - </tr> - <tr> - <td></td> - <td>RR</td> - <td class="tdr">4</td> - <td>F</td> - </tr> - <tr> - <td></td> - <td>W</td> - <td class="tdr">9</td> - <td>did in .22</td> - </tr> - <tr> - <td></td> - <td>Delta</td> - <td class="tdr">15</td> - <td>F</td> - </tr> - <tr> - <td></td> - <td>Epsilon</td> - <td class="tdr">40</td> - <td>F</td> - </tr> - <tr> - <td></td> - <td>QQ (f)</td> - <td class="tdr">15</td> - <td>F</td> - </tr> - <tr> - <td></td> - <td>QQ (c)</td> - <td class="tdr">1</td> - <td>did in 2.20</td> - </tr> - <tr> - <td>No. 3.—</td> - <td>Theta</td> - <td class="tdr">25</td> - <td>did in 3.00.</td> - </tr> - <tr> - <td></td> - <td>QQ</td> - <td class="tdr">40</td> - <td>F</td> - </tr> - <tr> - <td></td> - <td>Gamma</td> - <td class="tdr">30</td> - <td>F</td> - </tr> - <tr> - <td></td> - <td>Epsilon</td> - <td class="tdr">25</td> - <td>F</td> - </tr> - <tr> - <td></td> - <td>QQ (ff)</td> - <td class="tdr">5</td> - <td>F</td> - </tr> - <tr> - <td></td> - <td>QQ (c)</td> - <td class="tdr">20</td> - <td>F, did in 1.30, F, 5 F, 5 F</td> - </tr> - <tr> - <td></td> - <td>QQ (e)</td> - <td class="tdr">5</td> - <td>F, did in 2.00</td> - </tr> -</table> - -</div> - -<div class="footnote"> - -<p><a id="Footnote_31" href="#FNanchor_31" class="label">[31]</a> He did push it once with his nose.</p> - -</div> - -<div class="footnote"> - -<p><a id="Footnote_32" href="#FNanchor_32" class="label">[32]</a> I inadvertently pulled the nail out in one of five cases when I was fingering it to see if attracting his attention to it would lead to the act.</p> - -</div> - -<div class="footnote"> - -<p><a id="Footnote_33" href="#FNanchor_33" class="label">[33]</a> Not significant. Due to inattention. Was temporary.</p> - -</div> - -<div class="footnote"> - -<p><a id="Footnote_34" href="#FNanchor_34" class="label">[34]</a> Pulled wire and door.</p> - -</div> - -<div class="footnote"> - -<p><a id="Footnote_35" href="#FNanchor_35" class="label">[35]</a> Pushed with head by chance.</p> - -</div> - -<div class="footnote"> - -<p><a id="Footnote_36" href="#FNanchor_36" class="label">[36]</a> Reached in at 9:30 and took out the banana, which I replaced.</p> - -</div> - -<div class="footnote"> - -<p><a id="Footnote_37" href="#FNanchor_37" class="label">[37]</a> Did by constant pulling at the door.</p> - -</div> - -<div class="footnote"> - -<p><a id="Footnote_38" href="#FNanchor_38" class="label">[38]</a> Did touch nail four times.</p> - -</div> - -<div class="footnote"> - -<p><a id="Footnote_39" href="#FNanchor_39" class="label">[39]</a> Did by pulling hard on wire (not loop); the loop got loose from nail.</p> - -</div> - -<div class="footnote"> - -<p><a id="Footnote_40" href="#FNanchor_40" class="label">[40]</a> Did by pulling at the door till the bar was worked around.</p> - -</div> - -<div class="footnote"> - -<p><a id="Footnote_41" href="#FNanchor_41" class="label">[41]</a> The ‘say,’ may be replaced by some bodily attitude, facial expression, -or other verbal formula that identifies the situation as one to be responded -to by speech.</p> - -</div> - -<div class="footnote"> - -<p><a id="Footnote_42" href="#FNanchor_42" class="label">[42]</a> This would, of course, result from a well-known corollary of the laws of -habit.</p> - -</div> - -<div class="footnote"> - -<p><a id="Footnote_43" href="#FNanchor_43" class="label">[43]</a> In <i>Essays Philosophical and Psychological in Honor of William James</i>, -pp. 591-599.</p> - -</div> - -<div class="footnote"> - -<p><a id="Footnote_44" href="#FNanchor_44" class="label">[44]</a> Professor Smith’s own experiments illustrate this.</p> - -</div> - -<div class="footnote"> - -<p><a id="Footnote_45" href="#FNanchor_45" class="label">[45]</a> Biological Lectures from the Marine Biological Laboratory of Woods -Holl, 1898, p. 323 ff.</p> - -</div> - -<div class="footnote"> - -<p><a id="Footnote_46" href="#FNanchor_46" class="label">[46]</a> This chapter appeared originally in the <i>Popular Science Monthly</i>, Nov., -1901.</p> - -</div> - -</div> - -<hr class="chap x-ebookmaker-drop"> - -<div class="chapter"> - -<p><span class="pagenum"><a id="Page_295"></a>[295]</span></p> - -<h2 class="nobreak" id="INDEX">INDEX</h2> - -</div> - -<ul> - -<li class="ifrst">Abstraction, <a href="#Page_120">120</a>.</li> -<li class="isub1"><i>See also</i> <a href="#Reasoning">Reasoning</a>.</li> - -<li class="indx">Action-system, importance of the study of the, <a href="#Page_15">15 f.</a>;</li> -<li class="isub1">of monkeys, <a href="#Page_190">190 f.</a>, <a href="#Page_237">237</a>.</li> - -<li class="indx">Anecdotal school in animal psychology, <a href="#Page_23">23 ff.</a>, <a href="#Page_151">151 f.</a></li> - -<li class="indx">Apparatus, descriptions of, <a href="#Page_29">29 ff.</a>, <a href="#Page_56">56 ff.</a>, <a href="#Page_61">61 f.</a>, <a href="#Page_169">169 f.</a>, <a href="#Page_177">177 ff.</a>, <a href="#Page_196">196 ff.</a></li> - -<li class="indx">Assimilation, <a href="#Page_249">249 f.</a></li> - -<li class="indx" id="Association">Association, as a problem in animal psychology, <a href="#Page_20">20 ff.</a>;</li> -<li class="isub1">by similarity, <a href="#Page_116">116 ff.</a>;</li> -<li class="isub1">complexity of, <a href="#Page_132">132 ff.</a>;</li> -<li class="isub1">conditions of, <a href="#Page_43">43 ff.</a>;</li> -<li class="isub1">delicacy of, <a href="#Page_128">128 ff.</a>, <a href="#Page_195">195 ff.</a>;</li> -<li class="isub1">development of, in the animal kingdom, <a href="#Page_285">285 ff.</a>;</li> -<li class="isub1">in cats, <a href="#Page_38">38 ff.</a>;</li> -<li class="isub1">in chicks, <a href="#Page_63">63 f.</a>;</li> -<li class="isub1">in dogs, <a href="#Page_56">56 ff.</a>;</li> -<li class="isub1">in fishes, <a href="#Page_169">169 ff.</a>;</li> -<li class="isub1">in man, <a href="#Page_123">123 ff.</a>, <a href="#Page_127">127</a>, <a href="#Page_285">285</a>;</li> -<li class="isub1">in monkeys, <a href="#Page_182">182 ff.</a>, <a href="#Page_194">194 f.</a>, <a href="#Page_209">209 ff.</a>;</li> -<li class="isub1">in relation to attention, <a href="#Page_44">44 ff.</a>;</li> -<li class="isub1">to individual differences, <a href="#Page_52">52 ff.</a>;</li> -<li class="isub1">to inhibition, <a href="#Page_142">142 ff.</a>;</li> -<li class="isub1">to instincts, <a href="#Page_36">36 f.</a>, <a href="#Page_142">142 ff.</a>;</li> -<li class="isub1">to previous experience, <a href="#Page_48">48 ff.</a>;</li> -<li class="isub1">number of connections formed by, <a href="#Page_135">135 ff.</a>;</li> -<li class="isub1">permanence of connections formed by, <a href="#Page_138">138 ff.</a>, <a href="#Page_194">194 f.</a>, <a href="#Page_203">203 f.</a>;</li> -<li class="isub1">progress of, measurable by time-curves, <a href="#Page_28">28</a>, <a href="#Page_40">40</a>, <a href="#Page_42">42</a>;</li> -<li class="isub1">the mental fact in, <a href="#Page_98">98 ff.</a>;</li> -<li class="isub1">without ideas, <a href="#Page_101">101 f.</a>, <a href="#Page_127">127</a>, <a href="#Page_209">209 ff.</a></li> -<li class="isub1"><i>See also</i> <a href="#Association">Associations</a> and <a href="#Learning">Learning</a>.</li> - -<li class="indx">Associations, complexity, <a href="#Page_132">132 ff.</a>;</li> -<li class="isub1">delicacy, <a href="#Page_128">128 ff.</a>, <a href="#Page_195">195 ff.</a>;</li> -<li class="isub1">number, <a href="#Page_121">121</a>, <a href="#Page_135">135 ff.</a>;</li> -<li class="isub1">permanence, <a href="#Page_138">138 ff.</a>, <a href="#Page_194">194 f.</a>, <a href="#Page_203">203 f.</a></li> - -<li class="indx">Associative memory. <i>See</i> <a href="#Association">Association</a>.</li> - -<li class="indx">Attention, <a href="#Page_144">144 ff.</a>;</li> -<li class="isub1">and association, <a href="#Page_44">44 ff.</a>;</li> -<li class="isub1">to imposed movements, <a href="#Page_103">103 ff.</a></li> - -<li class="ifrst" id="Behavior">Behavior, acquired tendencies to, <a href="#Page_244">244 ff.</a> (<i>see also</i> <a href="#Association">Association</a>);</li> -<li class="isub1">evolution of, <a href="#Page_272">272 ff.</a>;</li> -<li class="isub1">general laws of, <a href="#Page_241">241 ff.</a>;</li> -<li class="isub1">indefiniteness of the term, <a href="#Page_5">5</a>;</li> -<li class="isub1">of cats, <a href="#Page_35">35 ff.</a>, <a href="#Page_88">88 f.</a>, and <i>passim</i>;</li> -<li class="isub1">of chicks, <a href="#Page_63">63 f.</a>, <a href="#Page_138">138</a>, <a href="#Page_143">143 f.</a>, <a href="#Page_156">156 ff.</a>, and <i>passim</i>;</li> -<li class="isub1">of dogs, <a href="#Page_59">59 ff.</a>, <a href="#Page_92">92 ff.</a>;</li> -<li class="isub1">of fishes, <a href="#Page_169">169 ff.</a>;</li> -<li class="isub1">of monkeys, <a href="#Page_182">182 ff.</a>;</li> -<li class="isub1">original tendencies to, <a href="#Page_242">242 f.</a> (<i>see also</i> <a href="#Instincts">Instincts</a>);</li> -<li class="isub1">predictability of, <a href="#Page_241">241 f.</a>;</li> -<li class="isub1">proposed simplification of the laws of, <a href="#Page_265">265 ff.</a>;</li> -<li class="isub1"><i>versus</i> consciousness as an object of study, <a href="#Page_1">1 ff.</a></li> -<li class="isub1"><i>See also</i> <a href="#Association">Association</a>, <a href="#Instincts">Instincts</a>, <a href="#Learning">Learning</a>, <a href="#Memory">Memory</a>, etc.</li> - -<li class="indx"><span class="smcap">Bosworth, F. D.</span>, <a href="#Page_240">240</a>.</li> - -<li class="ifrst">Cats, associative processes in, <a href="#Page_35">35 ff.</a>;</li> -<li class="isub1">imitation in, <a href="#Page_85">85 ff.</a>;</li> -<li class="isub1">the presence of ideas in, <a href="#Page_100">100 ff.</a>;</li> -<li class="isub1">reasoning in, <a href="#Page_67">67 ff.</a></li> - -<li class="indx">Chicks, associative processes in, <a href="#Page_61">61 ff.</a>;</li> -<li class="isub1">imitation in, <a href="#Page_81">81 ff.</a>;</li> -<li class="isub1">instincts of, <a href="#Page_156">156 ff.</a></li> - -<li class="indx">Complexity, of associations, <a href="#Page_132">132 ff.</a></li> - -<li class="indx">Concepts, <a href="#Page_116">116 ff.</a></li> - -<li class="indx">Connection-systems, action of, in association, <a href="#Page_246">246 ff.</a>, <a href="#Page_266">266</a>;</li> -<li class="isub1">importance of the study of, <a href="#Page_16">16 f.</a></li> - -<li class="indx">Consciousness, amenability of, to scientific study, <a href="#Page_7">7 ff.</a>;</li> -<li class="isub1">as pure experience, <a href="#Page_13">13 f.</a>;</li> -<li class="isub1">as studied by the one who has or is it, <a href="#Page_10">10 ff.</a>;</li> -<li class="isub1">of animals, <a href="#Page_25">25 f.</a>, <a href="#Page_67">67 ff.</a>, <a href="#Page_98">98 ff.</a>, <a href="#Page_123">123</a>, <a href="#Page_146">146 f.</a>, and <i>passim</i>;</li> -<li class="isub1">social, <a href="#Page_146">146 f.</a>;</li> -<li class="isub1">space-relations of, <a href="#Page_14">14</a>;</li> -<li class="isub1"><i>versus</i> behavior as an object of study, <a href="#Page_1">1 ff.</a></li> - -<li class="indx">Coördinations, of chicks, <a href="#Page_160">160 ff.</a></li> - -<li class="ifrst"><span class="smcap">Dean, B.</span>, <a href="#Page_161">161</a>.</li> - -<li class="indx">Delicacy of association, <a href="#Page_128">128 ff.</a>, <a href="#Page_195">195 ff.</a></li> - -<li class="indx"><span class="smcap">Dewey, J.</span>, <a href="#Page_6">6</a>.</li> - -<li class="indx">Differences, between species of animals in the associative processes, <a href="#Page_64">64 ff.</a></li> - -<li class="indx">Discomfort, as an influence in learning, <a href="#Page_245">245 ff.</a></li> - -<li class="indx">Discrimination, in cats and dogs, <a href="#Page_128">128 ff.</a>;</li> -<li class="isub1">in chicks, <a href="#Page_156">156 ff.</a>;</li> -<li class="isub1">in monkeys, <a href="#Page_195">195 ff.</a></li> - -<li class="indx">Dogs, associative processes in, <a href="#Page_56">56 ff.</a>;</li> -<li class="isub1">imitation in, <a href="#Page_91">91 ff.</a>;</li> -<li class="isub1">the presence of ideas in, <a href="#Page_115">115 f.</a>;</li> -<li class="isub1">reasoning in, <a href="#Page_67">67 ff.</a></li> - -<li class="ifrst">Education, applications of animal psychology in, <a href="#Page_149">149 f.</a></li> - -<li class="indx">Effect, the law of, <a href="#Page_244">244 f.</a>, <a href="#Page_266">266 ff.</a></li> - -<li class="indx">Emotional reactions of chicks, <a href="#Page_162">162 ff.</a></li> - -<li class="indx">Evolution, of behavior, <a href="#Page_272">272 ff.</a>;</li> -<li class="isub1">of human intellect, <a href="#Page_282">282 ff.</a>;</li> -<li class="isub1">of ideas, <a href="#Page_289">289 ff.</a></li> - -<li class="indx">Exercise, the law of, <a href="#Page_244">244 f.</a></li> - -<li class="indx"><span class="pagenum"><a id="Page_296"></a>[296]</span>Experience, the influence of previous, <a href="#Page_48">48 ff.</a></li> - -<li class="indx">Experiments, need of, in animal psychology, <a href="#Page_26">26</a>;</li> -<li class="isub1">with cats, <a href="#Page_35">35 ff.</a>, <a href="#Page_85">85 ff.</a>, <a href="#Page_103">103 ff.</a>, <a href="#Page_111">111 f.</a>, <a href="#Page_114">114 f.</a>, <a href="#Page_129">129 ff.</a>, <a href="#Page_138">138 f.</a>;</li> -<li class="isub1">with chicks, <a href="#Page_61">61 ff.</a>, <a href="#Page_81">81 ff.</a>, <a href="#Page_132">132</a>, <a href="#Page_136">136</a>, <a href="#Page_143">143 f.</a>, <a href="#Page_156">156 ff.</a>;</li> -<li class="isub1">with dogs, <a href="#Page_56">56 ff.</a>, <a href="#Page_91">91 ff.</a>, <a href="#Page_103">103 ff.</a>, <a href="#Page_115">115 f.</a>;</li> -<li class="isub1">with fishes, <a href="#Page_169">169 ff.</a>;</li> -<li class="isub1">with monkeys, <a href="#Page_176">176-235</a>, <i>passim</i>.</li> - -<li class="ifrst">Fears, of chicks, <a href="#Page_162">162 ff.</a></li> - -<li class="indx">Fishes, experiments with, <a href="#Page_169">169 ff.</a></li> - -<li class="ifrst"><span class="smcap">Galton, F.</span>, <a href="#Page_3">3</a>.</li> - -<li class="ifrst">Habit. <i>See</i> <a href="#Association">Association</a>.</li> - -<li class="indx"><span class="smcap">Hall, G. S.</span>, <a href="#Page_3">3</a>.</li> - -<li class="indx">Human. <i>See</i> <a href="#Man">Man</a>.</li> - -<li class="indx">Hunger, effect of, on animal learning, <a href="#Page_27">27 f.</a></li> - -<li class="indx"><span class="smcap">Hunt, H. E.</span>, <a href="#Page_163">163</a>.</li> - -<li class="ifrst" id="Ideas">Ideas, development of, <a href="#Page_121">121 f.</a>, <a href="#Page_289">289 ff.</a>;</li> -<li class="isub1">existence of, as adjuncts in animal learning, <a href="#Page_108">108 ff.</a>, <a href="#Page_189">189 ff.</a>, <a href="#Page_206">206 ff.</a>, <a href="#Page_222">222 ff.</a>;</li> -<li class="isub1">impotence of, to create connections, <a href="#Page_257">257 ff.</a></li> - -<li class="indx">Ideo-motor action, <a href="#Page_257">257 ff.</a></li> - -<li class="indx">Images, <a href="#Page_108">108 f.</a> <i>See also</i> <a href="#Ideas">Ideas</a>.</li> - -<li class="indx" id="Imitation">Imitation, analysis of the supposed effects of, <a href="#Page_251">251 ff.</a>;</li> -<li class="isub1">in cats, <a href="#Page_85">85 ff.</a>;</li> -<li class="isub1">in chicks, <a href="#Page_81">81 ff.</a>;</li> -<li class="isub1">in dogs, <a href="#Page_91">91 ff.</a>;</li> -<li class="isub1">in general, <a href="#Page_76">76 ff.</a>, <a href="#Page_94">94 ff.</a>;</li> -<li class="isub1">in monkeys, <a href="#Page_96">96</a>, <a href="#Page_211">211 ff.</a>, <a href="#Page_219">219 ff.</a>;</li> -<li class="isub1">in speech, <a href="#Page_253">253 ff.</a></li> - -<li class="indx">Impulses, as features of the associative processes, <a href="#Page_100">100 ff.</a>;</li> -<li class="isub1">defined, <a href="#Page_37">37</a>.</li> - -<li class="indx">Incubation, the instinct of, <a href="#Page_276">276 ff.</a></li> - -<li class="indx">Individual differences in association, <a href="#Page_52">52 ff.</a></li> - -<li class="indx">Inhibition of instincts by association, <a href="#Page_142">142 ff.</a></li> - -<li class="indx" id="Instincts">Instincts, as explanations of some cases of supposed imitation, <a href="#Page_251">251</a>;</li> -<li class="isub1">inhibition of, <a href="#Page_142">142 ff.</a>;</li> -<li class="isub1">of chicks, <a href="#Page_156">156 ff.</a>;</li> -<li class="isub1">of incubation, <a href="#Page_276">276 ff.</a>;</li> -<li class="isub1">of monkeys, <a href="#Page_237">237</a>;</li> -<li class="isub1">the starting-point of animal learning, <a href="#Page_36">36 f.</a></li> - -<li class="indx">Intellect. <i>See</i> <a href="#Association">Association</a>, <a href="#Ideas">Ideas</a>, <a href="#Imitation">Imitation</a>, <a href="#Memory">Memory</a>, <a href="#Reasoning">Reasoning</a>, etc.</li> - -<li class="indx">Interaction, <a href="#Page_147">147 f.</a></li> - -<li class="indx">Introspection, the over-emphasis of, <a href="#Page_3">3</a>.</li> - -<li class="ifrst"><span class="smcap">James, W.</span>, <a href="#Page_3">3</a>, <a href="#Page_120">120</a>, <a href="#Page_143">143</a>, <a href="#Page_286">286</a>.</li> - -<li class="indx"><span class="smcap">Jennings, H. S.</span>, <a href="#Page_267">267</a>, <a href="#Page_268">268</a>, <a href="#Page_269">269</a>, <a href="#Page_270">270</a>, <a href="#Page_274">274</a>, <a href="#Page_279">279</a>.</li> - -<li class="ifrst"><span class="smcap">Kline, L. W.</span>, <a href="#Page_173">173</a>.</li> - -<li class="ifrst">Language, <a href="#Page_253">253 ff.</a></li> - -<li class="indx" id="Learning">Learning, evolution of, <a href="#Page_278">278 ff.</a>;</li> -<li class="isub1">methods of, <a href="#Page_174">174 f.</a></li> -<li class="isub1"><i>See</i> <a href="#Association">Association</a>, <a href="#Behavior">Behavior</a>, <a href="#Ideas">Ideas</a>, <a href="#Imitation">Imitation</a>, <a href="#Reasoning">Reasoning</a>.</li> - -<li class="indx"><span class="smcap">Lubbock, J.</span>, <a href="#Page_240">240</a>.</li> - -<li class="ifrst" id="Man">Man, compared with lower animals in intellect, <a href="#Page_123">123 ff.</a>, <a href="#Page_239">239 f.</a>;</li> -<li class="isub1">mental evolution of, <a href="#Page_282">282 ff.</a></li> - -<li class="indx" id="Memory">Memory, <a href="#Page_108">108 f.</a>, <a href="#Page_138">138 ff.</a>, <a href="#Page_203">203</a>.</li> -<li class="isub1"><i>See</i> <a href="#Association">Association</a> and <a href="#Permanence">Permanence of associations</a>.</li> - -<li class="indx">Methods in animal psychology, <a href="#Page_22">22 ff.</a></li> - -<li class="indx"><span class="smcap">Mills, W.</span>, <a href="#Page_191">191</a>.</li> - -<li class="indx" id="Monkeys">Monkeys, <a href="#Page_172">172 ff.</a>;</li> -<li class="isub1">associative processes in, <a href="#Page_182">182 ff.</a>;</li> -<li class="isub1">differences from lower mammals, <a href="#Page_189">189 ff.</a>, <a href="#Page_204">204 ff.</a>, <a href="#Page_237">237 ff.</a>;</li> -<li class="isub1">general mental development of, <a href="#Page_236">236 ff.</a>;</li> -<li class="isub1">imitation of man by, <a href="#Page_211">211 ff.</a>;</li> -<li class="isub1">imitation of other monkeys by, <a href="#Page_219">219 ff.</a>;</li> -<li class="isub1">possible mental degeneracy of, <a href="#Page_151">151</a>;</li> -<li class="isub1">presence of ideas in, <a href="#Page_189">189 ff.</a>, <a href="#Page_206">206 ff.</a>, <a href="#Page_222">222 ff.</a>;</li> -<li class="isub1">reasoning in, <a href="#Page_184">184 ff.</a></li> - -<li class="indx"><span class="smcap">Morgan, C. L.</span>, <a href="#Page_3">3</a>, <a href="#Page_80">80</a>, <a href="#Page_99">99 f.</a>, <a href="#Page_101">101</a>, <a href="#Page_119">119</a>, <a href="#Page_120">120</a>, <a href="#Page_125">125 f.</a>, <a href="#Page_146">146</a>, <a href="#Page_147">147</a>, <a href="#Page_162">162</a>, <a href="#Page_165">165 f.</a></li> - -<li class="indx">Motives, used in the experiments, <a href="#Page_26">26 ff.</a>;</li> -<li class="isub1">defined, <a href="#Page_38">38</a>.</li> - -<li class="ifrst">Number of associations, <a href="#Page_135">135 ff.</a>;</li> -<li class="isub1">as a cause of the development of free ideas, <a href="#Page_121">121 f.</a></li> - -<li class="ifrst"><span class="smcap">Peckham, G. W.</span> and E. G., <a href="#Page_240">240</a>.</li> - -<li class="indx">Pecking, accuracy of, in chicks, <a href="#Page_159">159 f.</a></li> - -<li class="indx">Pedagogy, applications of animal psychology to, <a href="#Page_149">149 f.</a></li> - -<li class="indx" id="Permanence">Permanence of associations, <a href="#Page_138">138 ff.</a>, <a href="#Page_203">203</a>.</li> - -<li class="indx">Predictability of behavior, <a href="#Page_241">241 f.</a></li> - -<li class="indx">Primates. <i>See</i> <a href="#Monkeys">Monkeys</a>.</li> - -<li class="ifrst" id="Reasoning">Reasoning, <a href="#Page_118">118 f.</a>;</li> -<li class="isub1">and free ideas, <a href="#Page_291">291 ff.</a>;</li> -<li class="isub1">as a consequence of the laws of exercise and effect, <a href="#Page_263">263 ff.</a>;</li> -<li class="isub1">in cats and dogs, <a href="#Page_67">67 ff.</a>;</li> -<li class="isub1">in monkeys, <a href="#Page_184">184 ff.</a></li> - -<li class="indx">Recepts, <a href="#Page_120">120</a>.</li> - -<li class="indx">Resolution, Jennings’ law of, <a href="#Page_267">267 ff.</a></li> - -<li class="indx">Responses to situations as the general form of behavior, <a href="#Page_242">242 ff.</a>, <a href="#Page_283">283 f.</a></li> - -<li class="indx"><span class="smcap">Romanes, G. J.</span>, <a href="#Page_68">68 f.</a>, <a href="#Page_70">70</a>, <a href="#Page_80">80</a>.</li> - -<li class="ifrst"><span class="smcap">Santayana, G.</span>, <a href="#Page_6">6</a>, <a href="#Page_18">18 f.</a></li> - -<li class="indx">Satisfaction, the influence of, in learning, <a href="#Page_147">147 f.</a>, <a href="#Page_244">244 f.</a>;</li> -<li class="isub1">the nature of, <a href="#Page_245">245 f.</a></li> - -<li class="indx"><span class="pagenum"><a id="Page_297"></a>[297]</span>Situation and response as the general form of behavior, <a href="#Page_242">242 ff.</a>, <a href="#Page_283">283 ff.</a></li> - -<li class="indx"><span class="smcap">Small, W. S.</span>, <a href="#Page_173">173</a>.</li> - -<li class="indx"><span class="smcap">Smith, S.</span>, <a href="#Page_269">269 f.</a>, <a href="#Page_280">280</a>.</li> - -<li class="indx">Social consciousness of animals, <a href="#Page_146">146 f.</a></li> - -<li class="indx"><span class="smcap">Spalding, D. A.</span>, <a href="#Page_162">162</a>, <a href="#Page_163">163</a>, <a href="#Page_165">165</a>.</li> - -<li class="indx"><span class="smcap">Stout, G. F.</span>, <a href="#Page_3">3</a>.</li> - -<li class="indx">Swimming, by chicks, <a href="#Page_161">161 f.</a></li> - -<li class="ifrst">Time of achievement as a measure of the closeness of association, <a href="#Page_28">28</a>, <a href="#Page_40">40</a>, <a href="#Page_42">42</a>, <a href="#Page_54">54</a>.</li> - -<li class="indx">Time-curves, <a href="#Page_38">38 ff.</a>, <a href="#Page_57">57 ff.</a>, <a href="#Page_65">65</a>, <a href="#Page_185">185 f.</a>;</li> -<li class="isub1">as evidence against the existence of reasoning, <a href="#Page_73">73 f.</a></li> - -<li class="indx"><span class="smcap">Titchener, E. B.</span>, <a href="#Page_2">2</a>.</li> - -<li class="ifrst">Vigor, as a factor in learning, <a href="#Page_46">46</a>.</li> - -<li class="ifrst"><span class="smcap">Whitman, C. O.</span>, <a href="#Page_275">275 ff.</a></li> - -<li class="ifrst"><span class="smcap">Yerkes, R. M.</span>, <a href="#Page_240">240</a>.</li> - -</ul> - -<hr class="chap x-ebookmaker-drop"> - -<div class="chapter box"> - -<p class="noindent">The following pages contain advertisements -of Macmillan books on kindred subjects</p> - -</div> - -<p class="book">The Animal Behavior Series</p> - -<p class="author">Under the General Editorship of ROBERT M. YERKES, -Ph.D., Instructor in Comparative Philosophy, Harvard University</p> - -<p class="center smaller">The aim of the Series is to present a number of small volumes which -taken together shall form a comprehensive introduction -to Comparative Psychology</p> - -<p class="center"><i>NOW READY</i></p> - -<p class="book">The Dancing Mouse</p> - -<p class="author">By ROBERT M. YERKES, Ph.D.</p> - -<p class="right"><i>Cloth, 12mo, xxi + 290 pages, illus., $1.25 net</i></p> - -<p>“Dr. Yerkes’ book is a most interesting example of modern laboratory -methods and can be read with profit by any one, on account of the -accurate methods of observation and careful deductive reasoning -which it shows. An elaborate, painstaking system of experiments -was carried on with over 400 mice, with the object of determining -muscular coördination, structural peculiarities, strength of the special -sense organs, habit formation, educability, and strength of memory of -these little animals. Some experiments were also undertaken along -the line of inherited peculiarities.... The work is really only a -preliminary study, but it will be read with much interest by all -students of comparative psychology.”—<i>Journal of American Medical -Association.</i></p> - -<p class="book">The Animal Mind</p> - -<p class="author">By MARGARET FLOY WASHBURN, Ph.D., Professor -of Philosophy, Vassar College</p> - -<p class="right"><i>Cloth, 12mo, 333 pages, $1.60 net</i></p> - -<p>“As the author points out, the title of this book might more appropriately -have been ‘The Animal Mind Deduced from Experimental -Evidence,’ for the facts here set forth are very largely the results of -the experimental method in comparative psychology. The mass of -experimental material that has been accumulated from the researches -of physiologists and psychologists is already great, but is also for the -most part inaccessible to the ordinary student, being widely scattered -and to a considerable extent published in the journals of specialists, -which the average college library does not contain. Hence the usefulness -of the present ... interesting work.”—<i>New York Sun.</i></p> - -<p class="titlepage">The Series is Published by<br> -<span class="larger">THE MACMILLAN COMPANY</span><br> -64-66 Fifth Avenue, New York</p> - -<p class="titlepage larger">OTHER NATURE BOOKS</p> - -<p class="book">Four-Footed Americans <i>And their Kin</i></p> - -<p class="author">By MABEL OSGOOD WRIGHT. Edited by <span class="smcap">Frank M. -Chapman</span>. Illustrated by <span class="smcap">Ernest Seton Thompson</span></p> - -<p class="right"><i>Cloth, 12mo, $1.50 net; School Library Edition, 50 cents net</i></p> - -<p>“It deserves commendation for its fascinating style, and for the fund -of information which it contains regarding the familiar and many unfamiliar -animals of this country. It is an ideal book for children, and -doubtless older folk will find in its pages much of interest.”—<i>The -Dial.</i></p> - -<p>“Books like this are cups of delight to wide-awake and inquisitive -girls and boys. Here is a gossipy history of American quadrupeds, -bright, entertaining, and thoroughly instructive. The text, by Mrs. -Wright, has all the fascination that distinguishes her other outdoor -books.”—<i>The Independent.</i></p> - -<p class="book">Citizen Bird</p> - -<p><i>Scenes from Bird Life in Plain English for a Beginner</i></p> - -<p class="author">By MABEL O. WRIGHT and Dr. ELLIOTT COUES. -Profusely Illustrated by <span class="smcap">Louis Agassiz Fuertes</span></p> - -<p class="right"><i>Cloth, 12mo, $1.50 net; School Library Edition, 50 cents net</i></p> - -<p>“When two writers of marked ability in both literature and natural -history unite to produce a work giving scope to their special talents, -the public has reason to expect a masterpiece of its kind. In the -‘Citizen Bird,’ by Mabel O. Wright and Dr. Elliott Coues, this -expectation is realized—seldom is the plan of a book so admirably -conceived, and in every detail so excellently fulfilled.”—<i>The Dial.</i></p> - -<p>“There is no other book in existence so well fitted for arousing and -directing the interest that all children feel toward the birds.”—<i>Tribune</i>, -Chicago.</p> - -<p class="book">Flowers and Ferns <i>In their Haunts</i></p> - -<p class="author">By MABEL OSGOOD WRIGHT</p> - -<p class="right"><i>New Edition, cloth, 12mo, $2.00 net</i></p> - -<p>The subjects are treated in their relation to landscape—the whole -bound together with a thread of narrative. The book thus has the -fascination of romance, yet no better handbook could be found for the -study of the flowers in their natural surroundings. There are over 50 -full-page plates of the flowers where they live and grow, along the -roadside, in wood or by river. In addition to these plates, there are -over 100 illustrations in the text, made direct from photographs by the -author and by J. H. McFarland.</p> - -<p class="book">A Text-book on the Principles of Animal Histology</p> - -<p class="author">By ULRIC DAHLGREN, M.S., Assistant Professor of -Biology in Princeton University; and WILLIAM A. -KEPNER, A.B., Adjunct Professor of Biology in the -University of Virginia</p> - -<p class="right"><i>Cloth, 515 pp., 8vo, $3.75 net</i></p> - -<p>“The name of the senior author alone leads us to expect -much from this volume, and the most careful scrutiny -reveals almost no defects. It easily takes first place -among histologies, chiefly because of the invaluable comparative -element. With few exceptions, histologies, intended -as they have been primarily for the medical student, -have heretofore been based for the most part on the genus -<i>Homo</i>. Morphologists and anatomists will welcome a -general histology which in the widest sense holds to its -title, treating its subject as a pure science.... One -can scarcely imagine a clearer or better arranged text-book -either for the general student or for the specialist in any -of the many related sciences. Since scientists in many -fields often have occasion to refer to or to verify some -point in histology, the volume will appeal to readers outside -of the domain of histology proper.”—<i>New York -Evening Post.</i></p> - -<p>“In marked contrast to practically all the text-books of -histology in the English language, which deal largely or -exclusively with human or mammalian structures, this new -book discusses the tissues of all classes of animals. It is -therefore possible to treat the subject much more broadly -and satisfactorily than has hitherto been done.”—<i>American -Journal of Science.</i></p> - -<p>“When one considers the narrow, technical training which -students in histology usually receive, whether they be -medical students or not, one cannot but wish that a course -similar to that outlined in this book might be given in -every college and university.”—<i>Science.</i></p> - -<p class="book">A Synoptic Text-book of Zoölogy for Colleges and Schools</p> - -<p class="author">By ARTHUR WISSWALD WEYSSE, A.M., Ph.D. -(Harvard), Instructor in Zoölogy at the Massachusetts -Institute of Technology, and Associate Professor of Physiology -at Boston University</p> - -<p class="right"><i>Cloth, 545 pp., 8vo, $2.25 net</i></p> - -<p>“To relieve the tenseness of such a study as zoölogy, the author -deals—whenever practicable—with some facts of everyday interest, -such as the transmission of malaria by mosquitoes, the -division of labor among ants and bees, the storing of food for the -young, and several others of this character. These are pleasant -little oases in the wilderness of rigidly scientific terms and facts. -Not only is the author to be congratulated on the perseverance -which made the volume possible, but also are the publishers for -the mechanical part they have played. The book is entirely up to -the high standard of the house that publishes it. The illustrative -element is most meritorious.”—<i>Journal of Education.</i></p> - -<p>“A work of great value ... addressed to college students who -do not necessarily intend to become specialists, but approach the -subject with trained minds and with some knowledge of cognate -sciences. We begin, if not literally at the beginning, yet with the -protoplasmic cell, but pass almost immediately to the description -of the various animal types in which classification in minute subdivisions -is not attempted. A third part deals with the general -principles of zoölogy. The book has been specially adapted for -use in connection with laboratory and field work, as well as for -systematic study.”—<i>Churchman.</i></p> - -<p>“The text is noteworthy for its simplicity and clearness, and the -choice of subject-matter has been made with care. Considerable -attention has been paid to the introduction of illustrative data -which bear on general biological problems or are of economic or -sanitary importance. The book is also free from the more technical -terminology which only the specialist needs. The arrangement -of the subject-matter is excellent. After laying down a few -general principles, the various animal types are dealt with in -detail, and the theoretical phases and general problems are discussed -in the closing section. The book forms a clearly presented, -well-balanced, comprehensive, and accurate epitome of zoölogy.”—<i>The -Dial.</i></p> - -<p class="book">Experimental Zoölogy</p> - -<p class="author">By THOMAS HUNT MORGAN, Professor of Experimental -Zoölogy, Columbia University</p> - -<p class="right"><i>Cloth, 454 pp., 8vo, $2.75 net</i></p> - -<p>“The author long ago won his spurs in this field, through his -unrivaled researches in the phenomena of regeneration; and he -has now proved himself a master of compilation—selecting the -most significant experiments carried on in various countries, -weighing them fairly, and summing up with a conservatism which -is perhaps the most valuable feature of the book. The thoroughness -and lucidity of the work make it serve three distinct -purposes: the intelligent layman without any previous knowledge -of the subject may read and appreciate any part of it; the student -of experimental zoölogy will find it a veritable vade mecum; and -the advanced scientist will be glad to refer to the generous -summaries of literature relating to each subject.”—<i>Nation.</i></p> - -<p>“Professor Morgan has, however, done much sound and some -brilliant work. In his special field, the regrowth of amputated -parts and the relation of this property to the general theory of -evolution, his experiments have become classic, and he is himself -one of the first authorities in the world. His own eminence in the -field, combined with a simple, straightforward style, and a just -and sympathetic appreciation of the work of other men, even -when their opinions are opposed to his own, render him especially -well fitted to sum up the general results of the new science. -This he has accomplished with marked success in the work -before us. He has succeeded in bringing together a large body -of fact without becoming dull; without being fatuously ‘popular,’ -he has been untechnical and clear.”—<i>Boston Transcript.</i></p> - -<p class="book">The Protozoa</p> - -<p class="author">By GARY N. CALKINS, Ph.D., Instructor in Zoölogy, -Columbia University</p> - -<p class="right"><i>Cloth, 347 pp., 8vo, $3.00 net</i></p> - -<p>“The author has not aimed at putting forward an exhaustive, -severely scientific treatise upon the group in question. His work -may be described rather as a simple and intelligible introduction -to the study of the Protozoa and of the many fascinating biological -problems connected with, or illustrated by, this subdivision of the -animal kingdom, in such a way as to awaken the interest of the -beginner, no less than to strengthen the hands of the expert.”—<i>Nature.</i></p> - -<p class="book">Text-book of Palæontology</p> - -<p class="author">By KARL A. VON ZITTEL, Professor of Geology and -Palæontology in the University of Munich. Translated -and edited by CHARLES R. EASTMAN, Ph.D., in -charge of Vertebrate Palæontology in the Museum of Comparative -Zoölogy at Harvard College, Cambridge, Mass.</p> - -<p class="right"><i>Vol. I. Cloth, 670 pp., with 1476 woodcuts, 8vo, $7.50 net</i><br> -<i>Vol. II. Cloth, 283 pp., with 373 woodcuts, $3.00 net</i></p> - -<p><span class="smcap">Note.</span>—This English edition has been enlarged and revised by the -author and editor in collaboration with the following specialists: -C. E. Beecher, J. M. Clarke, W. H. Dall, G. J. Hinde, A. Hyatt, -J. S. Kingsley, H. A. Pilsbry, C. Schuchert, S. H. Scudder, W. P. -Sladen, E. O. Ulrich, C. Wachsmuth, A. S. Woodward, E. C. Case, -J. B. Hatcher, H. F. Osborn, S. W. Williston, F. A. Lucas.</p> - -<p class="book">A Text-book of General Bacteriology</p> - -<p class="author">By WILLIAM DODGE FROST, Ph.D., Associate Professor -of Bacteriology in the University of Wisconsin; and -EUGENE FRANKLIN McCAMPBELL, Ph.D., Associate -Professor of Bacteriology in the Ohio State University</p> - -<p class="right"><i>Cloth, 340 pp., $1.60 net</i></p> - -<p class="book">Comparative Anatomy of Vertebrates</p> - -<p class="author">Adapted from the German of <span class="smcap">Dr.</span> ROBERT WIEDERSHEIM, -Professor of Anatomy, and Director of the -Institute of Human and Comparative Anatomy in the -University of Freiburg-in-Baden. By W. N. PARKER, -Ph.D., Professor of Zoölogy at the University College of -South Wales and Monmouthshire in the University of -Wales</p> - -<p class="right"><i>Cloth, 576 pp., 8vo, $3.75 net</i></p> - -<p class="book">Text-book of the Embryology of Man and Mammals</p> - -<p class="author">By <span class="smcap">Dr.</span> OSCAR HERTWIG, Professor extraordinarius -of Anatomy and Comparative Anatomy, Director of the -II Anatomical Institute of the University of Berlin. Translated -from the Third German Edition by EDWARD L. -MARK, Ph.D., Hersey Professor of Anatomy in Harvard -University</p> - -<p class="right"><i>Cloth, 670 pp., 8vo, $5.25 net</i></p> - -<p class="titlepage">PUBLISHED BY<br> -<span class="larger">THE MACMILLAN COMPANY</span><br> -64-66 Fifth Avenue, New York</p> - -<div style='display:block; margin-top:4em'>*** END OF THE PROJECT GUTENBERG EBOOK ANIMAL INTELLIGENCE ***</div> -<div style='text-align:left'> - -<div style='display:block; margin:1em 0'> -Updated editions will replace the previous one—the old editions will -be renamed. -</div> - -<div style='display:block; margin:1em 0'> -Creating the works from print editions not protected by U.S. copyright -law means that no one owns a United States copyright in these works, -so the Foundation (and you!) can copy and distribute it in the United -States without permission and without paying copyright -royalties. Special rules, set forth in the General Terms of Use part -of this license, apply to copying and distributing Project -Gutenberg™ electronic works to protect the PROJECT GUTENBERG™ -concept and trademark. Project Gutenberg is a registered trademark, -and may not be used if you charge for an eBook, except by following -the terms of the trademark license, including paying royalties for use -of the Project Gutenberg trademark. If you do not charge anything for -copies of this eBook, complying with the trademark license is very -easy. You may use this eBook for nearly any purpose such as creation -of derivative works, reports, performances and research. Project -Gutenberg eBooks may be modified and printed and given away—you may -do practically ANYTHING in the United States with eBooks not protected -by U.S. copyright law. Redistribution is subject to the trademark -license, especially commercial redistribution. -</div> - -<div style='margin-top:1em; font-size:1.1em; text-align:center'>START: FULL LICENSE</div> -<div style='text-align:center;font-size:0.9em'>THE FULL PROJECT GUTENBERG LICENSE</div> -<div style='text-align:center;font-size:0.9em'>PLEASE READ THIS BEFORE YOU DISTRIBUTE OR USE THIS WORK</div> - -<div style='display:block; margin:1em 0'> -To protect the Project Gutenberg™ mission of promoting the free -distribution of electronic works, by using or distributing this work -(or any other work associated in any way with the phrase “Project -Gutenberg”), you agree to comply with all the terms of the Full -Project Gutenberg™ License available with this file or online at -www.gutenberg.org/license. -</div> - -<div style='display:block; font-size:1.1em; margin:1em 0; font-weight:bold'> -Section 1. General Terms of Use and Redistributing Project Gutenberg™ electronic works -</div> - -<div style='display:block; margin:1em 0'> -1.A. By reading or using any part of this Project Gutenberg™ -electronic work, you indicate that you have read, understand, agree to -and accept all the terms of this license and intellectual property -(trademark/copyright) agreement. If you do not agree to abide by all -the terms of this agreement, you must cease using and return or -destroy all copies of Project Gutenberg™ electronic works in your -possession. If you paid a fee for obtaining a copy of or access to a -Project Gutenberg™ electronic work and you do not agree to be bound -by the terms of this agreement, you may obtain a refund from the person -or entity to whom you paid the fee as set forth in paragraph 1.E.8. -</div> - -<div style='display:block; margin:1em 0'> -1.B. “Project Gutenberg” is a registered trademark. It may only be -used on or associated in any way with an electronic work by people who -agree to be bound by the terms of this agreement. There are a few -things that you can do with most Project Gutenberg™ electronic works -even without complying with the full terms of this agreement. See -paragraph 1.C below. There are a lot of things you can do with Project -Gutenberg™ electronic works if you follow the terms of this -agreement and help preserve free future access to Project Gutenberg™ -electronic works. See paragraph 1.E below. -</div> - -<div style='display:block; margin:1em 0'> -1.C. The Project Gutenberg Literary Archive Foundation (“the -Foundation” or PGLAF), owns a compilation copyright in the collection -of Project Gutenberg™ electronic works. Nearly all the individual -works in the collection are in the public domain in the United -States. If an individual work is unprotected by copyright law in the -United States and you are located in the United States, we do not -claim a right to prevent you from copying, distributing, performing, -displaying or creating derivative works based on the work as long as -all references to Project Gutenberg are removed. Of course, we hope -that you will support the Project Gutenberg™ mission of promoting -free access to electronic works by freely sharing Project Gutenberg™ -works in compliance with the terms of this agreement for keeping the -Project Gutenberg™ name associated with the work. You can easily -comply with the terms of this agreement by keeping this work in the -same format with its attached full Project Gutenberg™ License when -you share it without charge with others. -</div> - -<div style='display:block; margin:1em 0'> -1.D. The copyright laws of the place where you are located also govern -what you can do with this work. Copyright laws in most countries are -in a constant state of change. If you are outside the United States, -check the laws of your country in addition to the terms of this -agreement before downloading, copying, displaying, performing, -distributing or creating derivative works based on this work or any -other Project Gutenberg™ work. The Foundation makes no -representations concerning the copyright status of any work in any -country other than the United States. -</div> - -<div style='display:block; margin:1em 0'> -1.E. Unless you have removed all references to Project Gutenberg: -</div> - -<div style='display:block; margin:1em 0'> -1.E.1. The following sentence, with active links to, or other -immediate access to, the full Project Gutenberg™ License must appear -prominently whenever any copy of a Project Gutenberg™ work (any work -on which the phrase “Project Gutenberg” appears, or with which the -phrase “Project Gutenberg” is associated) is accessed, displayed, -performed, viewed, copied or distributed: -</div> - -<blockquote> - <div style='display:block; margin:1em 0'> - This eBook is for the use of anyone anywhere in the United States and most - other parts of the world at no cost and with almost no restrictions - whatsoever. You may copy it, give it away or re-use it under the terms - of the Project Gutenberg License included with this eBook or online - at <a href="https://www.gutenberg.org">www.gutenberg.org</a>. If you - are not located in the United States, you will have to check the laws - of the country where you are located before using this eBook. - </div> -</blockquote> - -<div style='display:block; margin:1em 0'> -1.E.2. If an individual Project Gutenberg™ electronic work is -derived from texts not protected by U.S. copyright law (does not -contain a notice indicating that it is posted with permission of the -copyright holder), the work can be copied and distributed to anyone in -the United States without paying any fees or charges. If you are -redistributing or providing access to a work with the phrase “Project -Gutenberg” associated with or appearing on the work, you must comply -either with the requirements of paragraphs 1.E.1 through 1.E.7 or -obtain permission for the use of the work and the Project Gutenberg™ -trademark as set forth in paragraphs 1.E.8 or 1.E.9. -</div> - -<div style='display:block; margin:1em 0'> -1.E.3. If an individual Project Gutenberg™ electronic work is posted -with the permission of the copyright holder, your use and distribution -must comply with both paragraphs 1.E.1 through 1.E.7 and any -additional terms imposed by the copyright holder. Additional terms -will be linked to the Project Gutenberg™ License for all works -posted with the permission of the copyright holder found at the -beginning of this work. -</div> - -<div style='display:block; margin:1em 0'> -1.E.4. Do not unlink or detach or remove the full Project Gutenberg™ -License terms from this work, or any files containing a part of this -work or any other work associated with Project Gutenberg™. -</div> - -<div style='display:block; margin:1em 0'> -1.E.5. Do not copy, display, perform, distribute or redistribute this -electronic work, or any part of this electronic work, without -prominently displaying the sentence set forth in paragraph 1.E.1 with -active links or immediate access to the full terms of the Project -Gutenberg™ License. -</div> - -<div style='display:block; margin:1em 0'> -1.E.6. You may convert to and distribute this work in any binary, -compressed, marked up, nonproprietary or proprietary form, including -any word processing or hypertext form. However, if you provide access -to or distribute copies of a Project Gutenberg™ work in a format -other than “Plain Vanilla ASCII” or other format used in the official -version posted on the official Project Gutenberg™ website -(www.gutenberg.org), you must, at no additional cost, fee or expense -to the user, provide a copy, a means of exporting a copy, or a means -of obtaining a copy upon request, of the work in its original “Plain -Vanilla ASCII” or other form. Any alternate format must include the -full Project Gutenberg™ License as specified in paragraph 1.E.1. -</div> - -<div style='display:block; margin:1em 0'> -1.E.7. Do not charge a fee for access to, viewing, displaying, -performing, copying or distributing any Project Gutenberg™ works -unless you comply with paragraph 1.E.8 or 1.E.9. -</div> - -<div style='display:block; margin:1em 0'> -1.E.8. You may charge a reasonable fee for copies of or providing -access to or distributing Project Gutenberg™ electronic works -provided that: -</div> - -<div style='margin-left:0.7em;'> - <div style='text-indent:-0.7em'> - • You pay a royalty fee of 20% of the gross profits you derive from - the use of Project Gutenberg™ works calculated using the method - you already use to calculate your applicable taxes. The fee is owed - to the owner of the Project Gutenberg™ trademark, but he has - agreed to donate royalties under this paragraph to the Project - Gutenberg Literary Archive Foundation. Royalty payments must be paid - within 60 days following each date on which you prepare (or are - legally required to prepare) your periodic tax returns. Royalty - payments should be clearly marked as such and sent to the Project - Gutenberg Literary Archive Foundation at the address specified in - Section 4, “Information about donations to the Project Gutenberg - Literary Archive Foundation.” - </div> - - <div style='text-indent:-0.7em'> - • You provide a full refund of any money paid by a user who notifies - you in writing (or by e-mail) within 30 days of receipt that s/he - does not agree to the terms of the full Project Gutenberg™ - License. You must require such a user to return or destroy all - copies of the works possessed in a physical medium and discontinue - all use of and all access to other copies of Project Gutenberg™ - works. - </div> - - <div style='text-indent:-0.7em'> - • You provide, in accordance with paragraph 1.F.3, a full refund of - any money paid for a work or a replacement copy, if a defect in the - electronic work is discovered and reported to you within 90 days of - receipt of the work. - </div> - - <div style='text-indent:-0.7em'> - • You comply with all other terms of this agreement for free - distribution of Project Gutenberg™ works. - </div> -</div> - -<div style='display:block; margin:1em 0'> -1.E.9. If you wish to charge a fee or distribute a Project -Gutenberg™ electronic work or group of works on different terms than -are set forth in this agreement, you must obtain permission in writing -from the Project Gutenberg Literary Archive Foundation, the manager of -the Project Gutenberg™ trademark. Contact the Foundation as set -forth in Section 3 below. -</div> - -<div style='display:block; margin:1em 0'> -1.F. -</div> - -<div style='display:block; margin:1em 0'> -1.F.1. Project Gutenberg volunteers and employees expend considerable -effort to identify, do copyright research on, transcribe and proofread -works not protected by U.S. copyright law in creating the Project -Gutenberg™ collection. Despite these efforts, Project Gutenberg™ -electronic works, and the medium on which they may be stored, may -contain “Defects,” such as, but not limited to, incomplete, inaccurate -or corrupt data, transcription errors, a copyright or other -intellectual property infringement, a defective or damaged disk or -other medium, a computer virus, or computer codes that damage or -cannot be read by your equipment. -</div> - -<div style='display:block; margin:1em 0'> -1.F.2. LIMITED WARRANTY, DISCLAIMER OF DAMAGES - Except for the “Right -of Replacement or Refund” described in paragraph 1.F.3, the Project -Gutenberg Literary Archive Foundation, the owner of the Project -Gutenberg™ trademark, and any other party distributing a Project -Gutenberg™ electronic work under this agreement, disclaim all -liability to you for damages, costs and expenses, including legal -fees. YOU AGREE THAT YOU HAVE NO REMEDIES FOR NEGLIGENCE, STRICT -LIABILITY, BREACH OF WARRANTY OR BREACH OF CONTRACT EXCEPT THOSE -PROVIDED IN PARAGRAPH 1.F.3. YOU AGREE THAT THE FOUNDATION, THE -TRADEMARK OWNER, AND ANY DISTRIBUTOR UNDER THIS AGREEMENT WILL NOT BE -LIABLE TO YOU FOR ACTUAL, DIRECT, INDIRECT, CONSEQUENTIAL, PUNITIVE OR -INCIDENTAL DAMAGES EVEN IF YOU GIVE NOTICE OF THE POSSIBILITY OF SUCH -DAMAGE. -</div> - -<div style='display:block; margin:1em 0'> -1.F.3. LIMITED RIGHT OF REPLACEMENT OR REFUND - If you discover a -defect in this electronic work within 90 days of receiving it, you can -receive a refund of the money (if any) you paid for it by sending a -written explanation to the person you received the work from. If you -received the work on a physical medium, you must return the medium -with your written explanation. The person or entity that provided you -with the defective work may elect to provide a replacement copy in -lieu of a refund. If you received the work electronically, the person -or entity providing it to you may choose to give you a second -opportunity to receive the work electronically in lieu of a refund. If -the second copy is also defective, you may demand a refund in writing -without further opportunities to fix the problem. -</div> - -<div style='display:block; margin:1em 0'> -1.F.4. Except for the limited right of replacement or refund set forth -in paragraph 1.F.3, this work is provided to you ‘AS-IS’, WITH NO -OTHER WARRANTIES OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT -LIMITED TO WARRANTIES OF MERCHANTABILITY OR FITNESS FOR ANY PURPOSE. -</div> - -<div style='display:block; margin:1em 0'> -1.F.5. Some states do not allow disclaimers of certain implied -warranties or the exclusion or limitation of certain types of -damages. If any disclaimer or limitation set forth in this agreement -violates the law of the state applicable to this agreement, the -agreement shall be interpreted to make the maximum disclaimer or -limitation permitted by the applicable state law. The invalidity or -unenforceability of any provision of this agreement shall not void the -remaining provisions. -</div> - -<div style='display:block; margin:1em 0'> -1.F.6. INDEMNITY - You agree to indemnify and hold the Foundation, the -trademark owner, any agent or employee of the Foundation, anyone -providing copies of Project Gutenberg™ electronic works in -accordance with this agreement, and any volunteers associated with the -production, promotion and distribution of Project Gutenberg™ -electronic works, harmless from all liability, costs and expenses, -including legal fees, that arise directly or indirectly from any of -the following which you do or cause to occur: (a) distribution of this -or any Project Gutenberg™ work, (b) alteration, modification, or -additions or deletions to any Project Gutenberg™ work, and (c) any -Defect you cause. -</div> - -<div style='display:block; font-size:1.1em; margin:1em 0; font-weight:bold'> -Section 2. Information about the Mission of Project Gutenberg™ -</div> - -<div style='display:block; margin:1em 0'> -Project Gutenberg™ is synonymous with the free distribution of -electronic works in formats readable by the widest variety of -computers including obsolete, old, middle-aged and new computers. It -exists because of the efforts of hundreds of volunteers and donations -from people in all walks of life. -</div> - -<div style='display:block; margin:1em 0'> -Volunteers and financial support to provide volunteers with the -assistance they need are critical to reaching Project Gutenberg™’s -goals and ensuring that the Project Gutenberg™ collection will -remain freely available for generations to come. In 2001, the Project -Gutenberg Literary Archive Foundation was created to provide a secure -and permanent future for Project Gutenberg™ and future -generations. To learn more about the Project Gutenberg Literary -Archive Foundation and how your efforts and donations can help, see -Sections 3 and 4 and the Foundation information page at www.gutenberg.org. -</div> - -<div style='display:block; font-size:1.1em; margin:1em 0; font-weight:bold'> -Section 3. Information about the Project Gutenberg Literary Archive Foundation -</div> - -<div style='display:block; margin:1em 0'> -The Project Gutenberg Literary Archive Foundation is a non-profit -501(c)(3) educational corporation organized under the laws of the -state of Mississippi and granted tax exempt status by the Internal -Revenue Service. The Foundation’s EIN or federal tax identification -number is 64-6221541. Contributions to the Project Gutenberg Literary -Archive Foundation are tax deductible to the full extent permitted by -U.S. federal laws and your state’s laws. -</div> - -<div style='display:block; margin:1em 0'> -The Foundation’s business office is located at 809 North 1500 West, -Salt Lake City, UT 84116, (801) 596-1887. Email contact links and up -to date contact information can be found at the Foundation’s website -and official page at www.gutenberg.org/contact -</div> - -<div style='display:block; font-size:1.1em; margin:1em 0; font-weight:bold'> -Section 4. Information about Donations to the Project Gutenberg Literary Archive Foundation -</div> - -<div style='display:block; margin:1em 0'> -Project Gutenberg™ depends upon and cannot survive without widespread -public support and donations to carry out its mission of -increasing the number of public domain and licensed works that can be -freely distributed in machine-readable form accessible by the widest -array of equipment including outdated equipment. Many small donations -($1 to $5,000) are particularly important to maintaining tax exempt -status with the IRS. -</div> - -<div style='display:block; margin:1em 0'> -The Foundation is committed to complying with the laws regulating -charities and charitable donations in all 50 states of the United -States. Compliance requirements are not uniform and it takes a -considerable effort, much paperwork and many fees to meet and keep up -with these requirements. We do not solicit donations in locations -where we have not received written confirmation of compliance. To SEND -DONATIONS or determine the status of compliance for any particular state -visit <a href="https://www.gutenberg.org/donate/">www.gutenberg.org/donate</a>. -</div> - -<div style='display:block; margin:1em 0'> -While we cannot and do not solicit contributions from states where we -have not met the solicitation requirements, we know of no prohibition -against accepting unsolicited donations from donors in such states who -approach us with offers to donate. -</div> - -<div style='display:block; margin:1em 0'> -International donations are gratefully accepted, but we cannot make -any statements concerning tax treatment of donations received from -outside the United States. U.S. laws alone swamp our small staff. -</div> - -<div style='display:block; margin:1em 0'> -Please check the Project Gutenberg web pages for current donation -methods and addresses. Donations are accepted in a number of other -ways including checks, online payments and credit card donations. To -donate, please visit: www.gutenberg.org/donate -</div> - -<div style='display:block; font-size:1.1em; margin:1em 0; font-weight:bold'> -Section 5. General Information About Project Gutenberg™ electronic works -</div> - -<div style='display:block; margin:1em 0'> -Professor Michael S. Hart was the originator of the Project -Gutenberg™ concept of a library of electronic works that could be -freely shared with anyone. For forty years, he produced and -distributed Project Gutenberg™ eBooks with only a loose network of -volunteer support. -</div> - -<div style='display:block; margin:1em 0'> -Project Gutenberg™ eBooks are often created from several printed -editions, all of which are confirmed as not protected by copyright in -the U.S. unless a copyright notice is included. Thus, we do not -necessarily keep eBooks in compliance with any particular paper -edition. -</div> - -<div style='display:block; margin:1em 0'> -Most people start at our website which has the main PG search -facility: <a href="https://www.gutenberg.org">www.gutenberg.org</a>. -</div> - -<div style='display:block; margin:1em 0'> -This website includes information about Project Gutenberg™, -including how to make donations to the Project Gutenberg Literary -Archive Foundation, how to help produce our new eBooks, and how to -subscribe to our email newsletter to hear about new eBooks. -</div> - -</div> -</body> -</html> diff --git a/old/69904-h/images/cover.jpg b/old/69904-h/images/cover.jpg Binary files differdeleted file mode 100644 index c598e1d..0000000 --- a/old/69904-h/images/cover.jpg +++ /dev/null diff --git a/old/69904-h/images/figure01.jpg b/old/69904-h/images/figure01.jpg Binary files differdeleted file mode 100644 index 6fffd3b..0000000 --- a/old/69904-h/images/figure01.jpg +++ /dev/null diff --git a/old/69904-h/images/figure02.jpg b/old/69904-h/images/figure02.jpg Binary files differdeleted file mode 100644 index 6893db7..0000000 --- a/old/69904-h/images/figure02.jpg +++ /dev/null diff --git a/old/69904-h/images/figure03.jpg b/old/69904-h/images/figure03.jpg Binary files differdeleted file mode 100644 index aee7443..0000000 --- a/old/69904-h/images/figure03.jpg +++ /dev/null diff --git a/old/69904-h/images/figure04.jpg b/old/69904-h/images/figure04.jpg Binary files differdeleted file mode 100644 index 147d600..0000000 --- a/old/69904-h/images/figure04.jpg +++ /dev/null diff --git a/old/69904-h/images/figure05.jpg b/old/69904-h/images/figure05.jpg Binary files differdeleted file mode 100644 index 9485d5d..0000000 --- a/old/69904-h/images/figure05.jpg +++ /dev/null diff --git a/old/69904-h/images/figure06.jpg b/old/69904-h/images/figure06.jpg Binary files differdeleted file mode 100644 index 989dec0..0000000 --- a/old/69904-h/images/figure06.jpg +++ /dev/null diff --git a/old/69904-h/images/figure07.jpg b/old/69904-h/images/figure07.jpg Binary files differdeleted file mode 100644 index 6b9e093..0000000 --- a/old/69904-h/images/figure07.jpg +++ /dev/null diff --git a/old/69904-h/images/figure08.jpg b/old/69904-h/images/figure08.jpg Binary files differdeleted file mode 100644 index 11c9aa0..0000000 --- a/old/69904-h/images/figure08.jpg +++ /dev/null diff --git a/old/69904-h/images/figure09.jpg b/old/69904-h/images/figure09.jpg Binary files differdeleted file mode 100644 index 3f4a25a..0000000 --- a/old/69904-h/images/figure09.jpg +++ /dev/null diff --git a/old/69904-h/images/figure10.jpg b/old/69904-h/images/figure10.jpg Binary files differdeleted file mode 100644 index 91f14ee..0000000 --- a/old/69904-h/images/figure10.jpg +++ /dev/null diff --git a/old/69904-h/images/figure11.jpg b/old/69904-h/images/figure11.jpg Binary files differdeleted file mode 100644 index db4207f..0000000 --- a/old/69904-h/images/figure11.jpg +++ /dev/null diff --git a/old/69904-h/images/figure12.jpg b/old/69904-h/images/figure12.jpg Binary files differdeleted file mode 100644 index 90df17b..0000000 --- a/old/69904-h/images/figure12.jpg +++ /dev/null diff --git a/old/69904-h/images/figure13.jpg b/old/69904-h/images/figure13.jpg Binary files differdeleted file mode 100644 index b1a178a..0000000 --- a/old/69904-h/images/figure13.jpg +++ /dev/null diff --git a/old/69904-h/images/figure14.jpg b/old/69904-h/images/figure14.jpg Binary files differdeleted file mode 100644 index a60d60f..0000000 --- a/old/69904-h/images/figure14.jpg +++ /dev/null diff --git a/old/69904-h/images/figure15-17.jpg b/old/69904-h/images/figure15-17.jpg Binary files differdeleted file mode 100644 index 26cf575..0000000 --- a/old/69904-h/images/figure15-17.jpg +++ /dev/null diff --git a/old/69904-h/images/figure18.jpg b/old/69904-h/images/figure18.jpg Binary files differdeleted file mode 100644 index b432c52..0000000 --- a/old/69904-h/images/figure18.jpg +++ /dev/null diff --git a/old/69904-h/images/figure19-20.jpg b/old/69904-h/images/figure19-20.jpg Binary files differdeleted file mode 100644 index ac0ddff..0000000 --- a/old/69904-h/images/figure19-20.jpg +++ /dev/null diff --git a/old/69904-h/images/figure21.jpg b/old/69904-h/images/figure21.jpg Binary files differdeleted file mode 100644 index 58a46a2..0000000 --- a/old/69904-h/images/figure21.jpg +++ /dev/null diff --git a/old/69904-h/images/figure22.jpg b/old/69904-h/images/figure22.jpg Binary files differdeleted file mode 100644 index 66a3033..0000000 --- a/old/69904-h/images/figure22.jpg +++ /dev/null diff --git a/old/69904-h/images/figure23.jpg b/old/69904-h/images/figure23.jpg Binary files differdeleted file mode 100644 index d045445..0000000 --- a/old/69904-h/images/figure23.jpg +++ /dev/null diff --git a/old/69904-h/images/figure24.jpg b/old/69904-h/images/figure24.jpg Binary files differdeleted file mode 100644 index 2004607..0000000 --- a/old/69904-h/images/figure24.jpg +++ /dev/null diff --git a/old/69904-h/images/figure25.jpg b/old/69904-h/images/figure25.jpg Binary files differdeleted file mode 100644 index 35a4b86..0000000 --- a/old/69904-h/images/figure25.jpg +++ /dev/null diff --git a/old/69904-h/images/figure26.jpg b/old/69904-h/images/figure26.jpg Binary files differdeleted file mode 100644 index 67701fd..0000000 --- a/old/69904-h/images/figure26.jpg +++ /dev/null diff --git a/old/69904-h/images/figure27.jpg b/old/69904-h/images/figure27.jpg Binary files differdeleted file mode 100644 index cd093fd..0000000 --- a/old/69904-h/images/figure27.jpg +++ /dev/null diff --git a/old/69904-h/images/figure28.jpg b/old/69904-h/images/figure28.jpg Binary files differdeleted file mode 100644 index 82b468d..0000000 --- a/old/69904-h/images/figure28.jpg +++ /dev/null diff --git a/old/69904-h/images/figure29.jpg b/old/69904-h/images/figure29.jpg Binary files differdeleted file mode 100644 index 5f4fcf7..0000000 --- a/old/69904-h/images/figure29.jpg +++ /dev/null diff --git a/old/69904-h/images/figure30.jpg b/old/69904-h/images/figure30.jpg Binary files differdeleted file mode 100644 index 3a6513e..0000000 --- a/old/69904-h/images/figure30.jpg +++ /dev/null diff --git a/old/69904-h/images/figure31.jpg b/old/69904-h/images/figure31.jpg Binary files differdeleted file mode 100644 index 6bcca7f..0000000 --- a/old/69904-h/images/figure31.jpg +++ /dev/null diff --git a/old/69904-h/images/figure32.jpg b/old/69904-h/images/figure32.jpg Binary files differdeleted file mode 100644 index a00ab56..0000000 --- a/old/69904-h/images/figure32.jpg +++ /dev/null diff --git a/old/69904-h/images/macmillan.jpg b/old/69904-h/images/macmillan.jpg Binary files differdeleted file mode 100644 index 3109bda..0000000 --- a/old/69904-h/images/macmillan.jpg +++ /dev/null |
