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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. 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