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The Project Gutenberg EBook of Psychology, by Robert S. Woodworth

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Title: Psychology
       A Study Of Mental Life

Author: Robert S. Woodworth

Release Date: February 25, 2010 [EBook #31382]

Language: English

Character set encoding: ASCII

*** START OF THIS PROJECT GUTENBERG EBOOK PSYCHOLOGY ***




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[Transcriber's notes]
  This text is derived from an unedited version in the Internet Archive.

  Page numbers are indicated by numbers enclosed in curly braces,
  e.g. {99}. They have been located where page breaks occurred in the
  original book.

  Labels and text in a figure that are not mentioned in the figure
  description are included as a comma separated list, as in "(Figure
  text: cochlea, vestibule, 3 Canals)".

  Lengthy footnotes and quotations are indented.

  Obvious misspellings and typos are corrected but inconsistent spelling
  is not resolved, as in coordinate and cooerdinate.

  Here are the definitions of some unfamiliar words (to me).

  amour propre
    self-esteem; self-respect.

  esprit de corps
    camaraderie, bonding, solidarity, fellowship.

  motility (motile)
    moving or capable of moving spontaneously.

  unwonted
    unusual.
[End Transcribers's notes]



PSYCHOLOGY
A STUDY OF MENTAL LIFE

BY
ROBERT S. WOODWORTH, Ph. D.
_Professor of Psychology in Columbia University_


NEW YORK
HENRY HOLT AND COMPANY
1921


COPYRIGHT, 1921
BY
HENRY HOLT AND COMPANY


Printed in the U.S.A.



PREFACE

A few words to the reader are in order. In the first place, something
like an apology is due for the free way in which the author has drawn
upon the original work of many fellow-psychologists, without any
mention of their names. This is practically unavoidable in a book
intended for the beginner, but the reader may well be informed of the
fact, and cautioned not to credit the content of the book to the
writer of it. The author's task has been that of selecting from the
large mass of psychological information now available, much of it new,
whatever seemed most suitable for introducing the subject to the
reader. The book aims to represent the present state of a very active
science.

Should the book appear unduly long in prospect, the longest and most
detailed chapter, that on Sensation, might perfectly well be omitted,
on the first reading, without appreciably disturbing the continuity of
the rest.

On the other hand should any reader desire to make this text the basis
of a more extensive course of reading, the lists of references
appended to the several chapters will prove of service. The books and
articles there cited will be found interesting and not too technical
in style.

Much advantage can be derived from the use of the "Exercises". The
text, at the best, but provides raw material. Each student's finished
product must be of his own making. The exercises afford opportunity
for the student to work over the material and make it his own.

A first or preliminary edition of this book, in mimeographed sheets,
was in use for two years in introductory classes conducted by the
author and his colleagues, and was subjected to exceedingly helpful
criticism from both teachers and students. The revision of that
earlier edition into the present form has been very much of a
cooeperative enterprise, and so many have cooeperated that room could
scarcely be found for all their names. Professor A. T. Poffenberger,
Dr. Clara F. Chassell, Dr. Georgina I. Gates, Mr. Gardner Murphy, Mr.
Harold E. Jones and Mr. Paul S. Achilles have given me the advantage
of their class-room experience with the mimeographed book. Dr.
Christine Ladd-Franklin has very carefully gone over with me the
passages dealing with color vision and with reasoning. Miss Elizabeth
T. Sullivan, Miss Anna B. Copeland, Miss Helen Harper and Dr. A. H.
Martin have been of great assistance in the final stages of the work.
Important suggestions have come also from several other universities,
where the mimeographed book was inspected.

R. S. W.
Columbia University
August, 1921



CONTENTS


CHAPTER I

                                       PAGE

WHAT PSYCHOLOGY IS AND DOES              1

Varieties of Psychology                  2

Psychology as Related to Other Sciences  5

The Science of Consciousness             7

The Science of Behavior                  8

Introspection                           10

Objective Observation                   11

General Lines of
  Psychological Investigation           14

Summary and Attempt at a Definition     17

Exercises                               19

References                              20


CHAPTER II

REACTIONS                               21

The Reaction Time Experiment            22

Reflex Action                           24

The Nerves in Reflex Action             26

Internal Construction of the
  Nerves and Nerve Centers              31

The Synapse                             34

Cooerdination                            37

Reactions in General                    39

Exercises                               42

References                              44


CHAPTER III

REACTIONS OF DIFFERENT LEVELS           45

Different Sorts of Stimuli              47

The Motor Centers, Lower and Higher     49

How the Brain Produces
  Muscular Movements                    53

Facilitation and Inhibition             54

Super-motor Centers in the Cortex       56

Speech Centers                          57

The Auditory Centers                    59

The Visual Centers                      62

Cortical Centers for the Other Senses   68

Lower Sensory Centers                   64

The Cerebellum                          66

Different Levels of Reaction            65

Exercises                               67

References                              67


CHAPTER IV

TENDENCIES TO REACTION                  68

Purposive Behavior                      70

Organic States that Influence Behavior  72

Preparation for Action                  74

Preparatory Reactions                   77

What the Preparatory
  Reactions Accomplish                  79

What a Tendency Is,
  in Terms of Nerve Action              82

Motives                                 84

Exercises                               86

References                              88


CHAPTER V

NATIVE AND ACQUIRED TRAITS              89

The Source of Native Traits             90

Reactions Appearing at
  Birth Must Be Native                  91

Reactions That Cannot Be
  Learned Must Be Native                92

Experimental Detection
  of Native Reactions                   93

Is Walking Native or Acquired?          95

Universality as a Criterion
  of Native Reactions                   97

Some Native Traits Are
  Far from Being Universal              98

Why Acquired Traits Differ from
  One Individual to Another             99

What Mental Traits Are Native?         100

Exercises                              103

References                             104


CHAPTER VI

INSTINCT                               105

The Difference Between
  an Instinct and a Reflex             107

An Instinct Is a Native
  Reaction-Tendency                    109

Fully and Partially
  Organized Instincts                  111

Instincts Are Not Ancestral Habits     113

Instincts Not Necessarily Useful
  in the Struggle for Existence        114

The So-called Instincts of
 Self-preservation and of Reproduction 115

Exercises                              117

References                             117


CHAPTER VII

EMOTION                                118

Organic States That Are
  Not Usually Classed as Emotions      119

How These Organic States
  Differ from Regular Emotions         120

The Organic State in Anger             121

Glandular Responses During Emotion     122

The Nerves Concerned in
  Internal Emotional Response          124

The Emotional State as
  a Preparatory Reaction               125

"Expressive Movements," Another
  Sort of Preparatory Reactions        126

Do Sensations of These Various
  Preparatory Reactions Constitute
  the Conscious State of Emotion?      128

The James-Lange Theory of the Emotions 129

Emotion and Impulse                    130

Emotion Sometimes Generates Impulse    132

Emotion and Instinct                   134

The Higher Emotions                    136

Exercises                              136

References                             136


CHAPTER VIII

INVENTORY OF HUMAN INSTINCTS
  AND PRIMARY EMOTIONS                 137

Classification                         138

Responses to Organic Needs             139

Instinctive Responses to Other Persons 145

The Play Instincts                     151

Exercises                              170

References                             171


CHAPTER IX

THE FEELINGS                           172

Pleasantness and Unpleasantness
  Are Simple Feelings                  173

Felling-tone of Sensations             174

Theories of Feeling                    175

Sources of Pleasantness
  and Unpleasantness                   178

Primary Likes and Dislikes             180

Other Proposed Elementary Feelings     184

Exercises                              186

References                             186


CHAPTER X

SENSATION                              187

The Sense Organs                       188

Analysis of Sensations                 197

The Skin Senses                        197

The Sense of Taste                     201

The Sense of Smell                     203

Organic Sensations                     204

The Sense of Sight                     204

Simpler Forms of the Color Sense       209

Visual Sensations as
  Related to the Stimulus              212

Color Mixing                           214

What Are the Elementary
  Visual Sensations?                   216

Theories of Color Vision               220

Adaptation                             224

Rod and Cone Vision                    226

After-images                           226

Contrast                               227

The Sense of Hearing                   228

Comparison of Sight and Hearing        231

Theory of Hearing                      234

Senses of Bodily Movement              236

Exercises                              241

References                             243


CHAPTER XI

ATTENTION                              244

The Stimulus, or
  What Attracts Attention              245

The Motor Reaction in Attention        248

The Shifting of Attention              251

Laws of Attention and
  Laws of Reaction in General          256

Sustained Attention                    257

Distraction                            259

Doing Two Things at Once               260

The Span of Attention                  261

Summary of the Laws of Attention       262

Attention and Degree of Consciousness  265

The Management of Attention            267

Theory of Attention                    268

Exercises                              270

References                             270


CHAPTER XII

INTELLIGENCE                           271

Intelligence Tests                     272

Performance Tests                      275

Group Testing                          276

Some Results of the Intelligence Tests 278

Limitations of the Intelligence Tests  281

The Correlation of Abilities           288

General Factors in Intelligence        285

Special Aptitudes                      288

Heredity of Intelligence
  and of Special Aptitudes             289

Intelligence and the Brain             292

Exercises                              294

References                             295


CHAPTER XIII

LEARNING AND HABIT FORMATION           296

Acquired Reactions Are
  Modified Native Reactions            297

Acquired Tendencies                    299

Animal Learning                        302

Summary of Animal Learning             310

Human Learning                         311

Human Compared with Animal Learning    313

Learning by Observation                317

The Learning of Complex
  Practical Performances               321

Higher Units and Overlapping           323

Moderate Skill Acquired in
  the Ordinary Day's Work              326

Habit                                  328

Exercises                              330

References                             331


CHAPTER XIV

MEMORY                                 332

The Process of Memorizing              333

Economy in Memorizing                  333

Unintentional Learning                 346

Retention                              348

Recall                                 364

Recognition                            357

Memory Training                        360

Exercises                              364

References                             365


CHAPTER XV

ASSOCIATION AND MENTAL IMAGERY         366

What Can Be Recalled                   366

Memory Images                          368

Limitations of Imagery                 371

The Question of Non-Sensory Recall     373

Hallucinations                         375

Free Association                       376

Controlled Association                 381

Examples of Controlled Association     384

Exercises                              386

References                             388


CHAPTER XVI

THE LAWS OF ASSOCIATION                389

The Law of Exercise                    389

The Law of Effect                      391

Limitations of the Law of Exercise     393

Association by Similarity              395

Association by Contiguity              396

The Law of Combination                 398

The Law of Combination in Recall       413

The Laws of Learning in
  Terms of the Neurones                414

Exercises                              418

References                             418


CHAPTER XVII

PERCEPTION                             418

Some Definitions                       421

The Difference Between
  Perception and Sensation             423

Perception and Image                   425

Perception and Motor Reaction          427

What Sort of Response,
  Then, Is Perception?                 431

Practiced Perception                   433

Corrected Perception                   435

Sensory Data Serving as Signs
  of Various Sorts of Fact             437

The Perception of Space                439

Esthetic Perception                    443

Social Perception                      444

Errors of Perception                   446

Illusions                              450

Exercises                              460

References                             461


CHAPTER XVIII

REASONING                              462

Animal and Human Exploration           463

Reasoning Culminates in Inference      465

Varieties of Reasoning                 468

Deductive and Inductive Reasoning      474

Psychology and Logic                   476

Exercises                              480

References                             480


CHAPTER XIX

IMAGINATION                            481

Beginnings of Imagination
  in the Child                         482

Preliminary Definition of Imagination  483

Play                                   485

The Play Motives                       488

Empathy                                491

Worry                                  497

Day Dreams                             498

Dreams                                 499

Freud's Theory of Dreams               505

Autistic Thinking                      508

Invention and Criticism                509

The Enjoyment of Imaginative Art       512

The Psychology of Inventive Production 517

Imagination Considered in General      519

Exercises                              521

References                             522


CHAPTER XX

WILL                                   523

Voluntary and Involuntary Action       524

Development of Voluntary Control       526

Ideomotor Action                       527

Conflict and Decision                  528

Obstruction and Effort                 535

Thought and Action                     539

Securing Action                        541

The Influence of Suggestion            546

Exercises                              551

References                             561


CHAPTER XXI

PERSONALITY                            552

Factors in Personality                 553

The Self                               555

Integration and Disintegration
  of the Personality                   558

The Unconscious, or,
  the Subconscious Mind                561

Unconscious Wishes and Motives         565

Exercises                              571

References                             571

INDEX                                  573


{1}

PSYCHOLOGY

CHAPTER I

WHAT PSYCHOLOGY IS AND DOES

THE SUBJECT-MATTER OF THE SCIENCE, ITS PROBLEMS AND ITS METHODS


Modern psychology is an attempt to bring the methods of scientific
investigation, which have proved immensely fruitful in other fields,
to bear upon mental life and its problems. The human individual, the
main object of study, is so complex an object, that for a long time it
seemed doubtful whether there ever could be real science here; but a
beginning was made in the nineteenth century, following the lead of
biology and physiology, and the work of the investigator has been so
successful that to-day there is quite a respectable body of knowledge
to assemble under the title of scientific psychology.

Psychology, then, is a science. It is the science of--what shall we
say? "The science of the soul"--that is what the name means by
derivation and ancient usage. "The science of the mind" has a more
modern sound. "The science of consciousness" is more modern still.
"The science of behavior" is the most recent attempt at a concise
formula.

None of these formulas is wholly satisfactory. Psychology does not
like to call itself the science of the soul, for that has a
theological tang and suggests problems that have so far not seemed
accessible to scientific investigation. Psychology does not like very
well to call itself the science {2} of the mind, as _the_ mind seems to
imply some thing or machine, and there is no such thing to be observed
(unless it be the brain and body generally), and, anyway, psychology
is distinctly a study of actions rather than of things. Psychology
does not like to limit itself to the study of consciousness, but finds
it necessary to study also unconscious actions. As to "behavior", it
would be a very suitable term, if only it had not become so closely
identified with the "behavioristic movement" in psychology, which
urges that consciousness should be entirely left out of psychology, or
at least disregarded. "Behavior psychology", as the term would be
understood to-day, means a part of the subject and not the whole.

[Footnote: A series of waggish critics has evolved the following:
"First psychology lost its soul, then it lost its mind, then it lost
consciousness; it still has behavior, of a kind."]

The best way of getting a true picture of psychology, and of reaching
an adequate definition of its subject-matter, would be to inspect the
actual work of psychologists, so as to see what kind of knowledge they
are seeking. Such a survey would reveal quite a variety of problems
under process of investigation, some of them practical problems,
others not directly practical.


Varieties of Psychology


Differential psychology.

One line of question that always interests the beginner in psychology
is as to how people differ--how different people act under the same
circumstances--and why; and if we watch the professional
psychologist, we often find him working at just this problem. He tests
a great number of individuals to see how they differ, and tries to
discover on what factors their differences depend, how far on
heredity, how far on environment. The "psychologist" in such a place
as the children's court {3} is a specialist whose duty it is to test
the delinquent children that are brought before the court, with the
special object of measuring the intelligence of each individual child
and of helping in other ways to understand the child's peculiar
conduct and attitude.

The "psychological examiner" in the Army, during the Great War, had the
same general object in view. It was desirable to measure the
intelligence of each recruit as he entered the service, since military
experience had shown that men of low intelligence made poor soldiers,
while those of high intelligence made the best officers and
non-commissioned officers, provided they also possessed good physique
and certain less measureable mental qualifications, such as courage
and leadership.


Applied psychology.

The Army psychologists, like the court psychologist, were engaged in
applying scientific knowledge to the practical problems of life; and
there are many other applications of psychology, to education, to
medicine, to business and other occupations, as well as to the art of
right living. Scientific knowledge enables you to _predict_ and
_control_. Having devised scientific tests for intelligence, you can
predict of a six-year-old boy who tests low, that he will not get much
good from the regular classes in school; and thus you are in a
position to control the education of this boy for his own best
interests. In the Army, it happened during the earlier part of the war
that some companies or regiments made much slower progress in training
than others; and a whole Division was delayed for months because of
the backwardness of a single regiment. When the psychological tests
were introduced, these slow-learning units were found to contain a
disproportionate number of men of low intelligence. From that time on,
it was possible by aid of the tests to equalize the intelligence of
different units when first formed, and thus insure equal {4} progress
in training. This was a good example of "control".

Most of us are attracted by the practical use of a science, and some
have no patience with any study that does not seem immediately
practical. But really any science, however much it is applied, must
remain fundamentally a pure science; that is, it must seek most of all
to know and understand. Practical scientific knowledge was usually
first obtained without any inkling of how it might be used. The
science of electricity is the most striking example of this. It began
as an attempt to understand certain curious phenomena, which seemed to
be nothing but curiosities; yet when the knowledge of these phenomena
had progressed to a certain point, abundant use was found for it. Much
the same is true of psychology, which began as a pure science and only
recently has found ways of applying its discoveries to practical
affairs. So the student beginning the science, though properly
desirous of making practical use of what he learns, should let himself
be governed for the present by the desire to know and understand,
confident that the more scientific (which is to say, the more
complete, systematic and reliable) his knowledge is, the more
available it will be for practical application.


General psychology.

Our science is not concerned entirely with differences between people,
but asks also in what ways people are alike, and this is indeed its
central problem. How do "we" observe, learn, remember, imagine, think?
What sensations and feelings do we have, what emotions, what
instincts, what natural and acquired impulses to action? How are our
natural powers and impulses developed and organized as we grow up?
Psychology is concerned with the child as well as the adult, and it is
even concerned with the animal. It is concerned with the abnormal as
well as the normal human being. So you will find books and {5} courses
on animal psychology, child psychology, abnormal psychology. Now
general psychology--or just plain "psychology"--has to do with the
main laws and principles that hold in all these special fields.


Psychology as Related to Other Sciences

A good definition of our science would distinguish it from other
sciences, especially from those neighboring sciences with which it is
in closest contact.


Psychology and sociology.

There is no difficulty in framing a good logical distinction here.
Sociology studies the activities of a group of people taken as a
whole, while psychology studies the activities of the individuals.
Both might be interested in the same social act, such as an election,
but sociology would consider this event as a unit, whereas psychology
would break it up into the acts of the several voters. The distinction
is clear enough theoretically, but breaks down often in practice, as
sociology would like to know the motives that swayed individual
voters, while psychology on its side is interested to know what
decision was reached by the majority. All the social sciences,
including economics and politics, have a psychological side, since
they evidently are concerned to know the causes that govern human
conduct. Social psychology studies the individual in his social
relations.


Psychology and biology.

Biology, being the science of living creatures, includes psychology,
which studies these creatures on the mental side. The science of life
includes the science of mental life. We may call psychology a part of
biology, or we may call it one of the biological sciences. It has very
close contact with several other branches of biology. Animal
psychology overlaps that part of zoology which studies the behavior of
animals. Genetic psychology, as it is sometimes called, i.e., the
study of mental heredity. {6} and development, dovetails with the
general biological science of genetics, so that we find biologists
gathering data on the heredity of feeble-mindedness or of musical
ability, while psychologists discuss the general theory of heredity.


Psychology and physiology.

That one of all the sciences that has the closest contacts with
psychology is human and animal physiology. Broadly defined, physiology
is that part of biology that studies functions or activities; and, so
defined, it includes psychology as part of itself. In practice,
psychology devotes itself to desire, thought, memory, and such "mental
functions", while physiology concentrates its effort upon "bodily
functions" like digestion and circulation. But this is only a rough
distinction, which breaks down at many points.

Where shall we class sensation? Is it "mental" or "bodily"? Both
sciences study it. Physiology is perhaps more apt to go into the
detailed study of the action of the sense organs, and psychology to
concern itself with the classification of sensations and the use made
of them for recognizing objects or for esthetic purposes. But the line
between the two sciences is far from sharp at this point.

Speech, also, lies in both provinces. Physiology has studied the
action of the vocal organs and the location of the brain centers
concerned in speech, while psychology has studied the child's process
of learning to speak and the relation of speech to thought, and is
more apt to be interested in stuttering, slips of the tongue, and
other speech disturbances which are said to be "mental rather than
physical".

It would be hard to mention any activity that is mental without being
physical at the same time. Even thinking, which seems as purely mental
as any, requires brain action; and the brain is just as truly a bodily
organ as the heart or stomach. Its activity is bodily activity and
lies properly within the field of physiology.

{7}

But it would be equally difficult to mention any function that is
exclusively bodily, and not mental at the same time, in some degree.
Take digestion for example: the pleasant anticipation of food will
start the digestive juices flowing, before any food is physically in
the stomach; while in anger or fear digestion comes to a sudden halt.
Therefore we find physiologists interested in these emotions, and
psychologists interested in digestion.

We do not find any clean separation between our science and
physiology; but we find, on the whole, that psychology examines what
are called "mental" activities, and that it studies them as the
performances of the whole individual rather than as executed by the
several organs.


The Science of Consciousness

Typically, the activities that psychology studies are conscious
performances, while many of those falling to physiology are
unconscious. Thus digestion is mostly unconscious, the heart beat is
unconscious except when disturbed, the action of the liver is entirely
unconscious. Why not say, then, that psychology is the study of
conscious activities?

There might be some objection to this definition from the side of
physiology, which studies certain conscious activities itself--speech,
for example, and especially sensation.

There would be objection also from the side of psychology, which does
not wish to limit itself to conscious action. Take the case of any act
that can at first be done only with close attention, but that becomes
easy and automatic after practice; at first it is conscious, later
unconscious, but psychology would certainly need to follow it from the
initial to the final stage, in order to make a complete study of the
practice effect. And then there is the "unconscious", or the
"subconscious mind"--a matter on which psychologists {8} do not wholly
agree among themselves; but all would agree that the problem of the
unconscious was appropriate to psychology.

For all the objections, it remains true that the _typical_ mental
process, the typical matter for psychological study, is conscious.
"Unconscious mental processes" are distinguished from the unconscious
activity of such organs as the liver by being somehow _like_ the
conscious mental processes.

It would be correct, then, to limit psychology to the study of
conscious activities and of activities akin to these.


The Science of Behavior

No one has objected so strenuously to defining psychology as the
science of consciousness, and limiting it to consciousness, as the
group of animal psychologists. By energetic work, they had proved that
the animal was a very good subject for psychological study, and had
discovered much that was important regarding instinct and learning in
animals. But from the nature of the case, they could not observe the
consciousness of animals; they could only observe their behavior, that
is to say, the motor (and in some cases glandular) activities of the
animals under known conditions. When then the animal psychologists
were warned by the mighty ones in the science that they must interpret
their results in terms of consciousness or not call themselves
psychologists any longer, they rebelled; and some of the best fighters
among them took the offensive, by insisting that human psychology, no
less than animal, was properly a study of behavior, and that it had
been a great mistake ever to define it as the science of
consciousness.

It is a natural assumption that animals are conscious, but after all
you cannot directly observe their consciousness, and you cannot
logically confute those philosophers {9} who have contended that the
animal was an unconscious automaton. Still less can you be sure in
detail what is the animal's sensation or state of mind at any time; to
get at that, you would need a trustworthy report from the animal
himself. Each individual must observe his own consciousness; no one
can do it from outside. The objection of the behaviorist to
"consciousness psychology" arises partly from distrust of this method
of inner observation, even on the part of a human observer.

Indeed, we can hardly define psychology without considering its
_methods of observation_, since evidently the method of observation
limits the facts observed and so determines the character of the
science. Psychology has two methods of observation.

When a person performs any act, there are, or may be, two sorts of
facts to be observed, the "objective" and the "subjective". The
objective facts consist of movements of the person's body or of any
part of it, secretions of his glands (as flow of saliva or sweat), and
external results produced by these bodily actions--results such as
objects moved, path and distance traversed, hits on a target, marks
made on paper, columns of figures added, vocal or other sounds
produced, etc., etc. Such objective facts can be observed by another
person.

The subjective facts can be observed only by the person performing the
act. While another person can observe, better indeed than he can
himself, the motion of his legs in walking, he alone can observe the
sensations in the joints and muscles produced by the leg movement. No
one else can observe his pleased or displeased state of mind, nor
whether he is thinking of his walking or of something quite different.
To be sure, his facial expression, which is an objective fact, may
give some clue to his thoughts and feelings, but "there's no art to
read the mind's construction {10} in the face", or at least no sure
art. One may feign sleep or absorption while really attending to what
is going on around. A child may wear an angelic expression while
meditating mischief. To get the subjective facts, we shall have to
enlist the person himself as our observer.


Introspection

This is observation by an individual of his own conscious action. It
is also called subjective observation. Notice that it is a form of
observation, and not speculation or reasoning from probabilities or
from past experience. It is a direct observation of fact.

One very simple instance of introspection is afforded by the study of
after-images. Look for an instant at the glowing electric bulb, and
then turn your eyes upon a dark background, and observe whether the
glowing filament appears there; this would be the "positive
after-image". This simple type of introspection is used by physiology
in its study of the senses, as well as by psychology; and it gives
such precise and regular results that only the most confirmed
behaviorists refuse to admit it as a good method of observation.

But psychology would like to make introspective observations on the
more complex mental processes as well; and it must be admitted that
here introspection becomes difficult. You cannot hope to make minute
observations on any process that lasts over a very few seconds, for
you must let the process run its natural course unimpeded by your
efforts at observing it, and then turn your "mental eye" instantly
back to observe it _retrospectively_ before it disappears. As a matter
of fact, a sensation or feeling or idea hangs on in consciousness for
a few seconds, and can be observed in this retrospective way. There is
no theoretical objection to this style of introspection, but it is
practically difficult and {11} tricky. Try it on a column of figures:
first add the column as usual, then immediately turn back and review
exactly what went through your mind in the process of adding---what
numbers you spoke internally, etc. Try again by introspecting the
process of filling in the blanks in the sentence:

"Botany could not make use of introspection because ______ have
probably no ________ processes."

At first, you may find it difficult to observe yourself in this way;
for the natural tendency, when you are aiming at a certain result, is
to reach the goal and then shift to something else, rather than to
turn back and review the steps by which you reached the goal. But with
practice, you acquire some skill in introspection.

One difficulty with introspection of the more complex mental processes
is that individuals vary more here than in the simpler processes, so
that different observers, observing each his own processes, will not
report the same facts, and one observer cannot serve as a check upon
another so easily as in the simpler introspection of after-images and
other sensations, or as in the observations made in other sciences.
Even well trained introspectionists are quite at variance when they
attempt a minute description of the thought processes, and it is
probable that this is asking too much of introspection. We mustn't
expect it to give microscopic details. Rough observations, however, it
gives with considerable certainty. Who can doubt, for example, that a
well-practised act goes on with very little consciousness, or that
inner, silent speech often accompanies thinking? And yet we have only
introspection to vouch for these facts.


Objective Observation

But to say, as used to be said, that psychology is purely an
introspective science, making use of no other sort of observation, is
absurd in the face of the facts.

{12}

We have animal psychology, where the observation is exclusively
objective. In objective observation, the observer watches something
else, and not himself. In animal psychology, the psychologist, as
observer, watches the animal.

The same is true of child psychology, at least for the first years of
childhood. You could not depend on the introspections of a baby, but
you can learn much by watching his behavior. Abnormal persons, also,
are not often reliable introspectionists, and the study of abnormal
psychology is mostly carried on by objective methods.

Now how is it with the normal adult human being, the standard subject
for psychology? Does he make all the observations on himself or may he
be objectively observed by the psychologist? The latter, certainly. In
fact, nearly all tests, such as those used in studying differential
psychology, are objective. That is to say that the person tested is
given a task to perform, and his performance is observed in one way or
another by the examiner. The examiner may observe the _time_ occupied
by the subject to complete the task, or the _quantity_ accomplished in
a fixed time; or he may measure the correctness and _excellence_ of
the work done, or the _difficulty_ of the task assigned. One test uses
one of these measures, and another uses another; but they are all
objective measures, not depending at all on the introspection of the
subject.

What is true of tests in differential psychology is true of the
majority of experiments in general psychology: the performer is one
person, the observer another, and the observation is objective in
character. Suppose, for example, you are investigating a memory
problem; your method may be to set your subject a lesson to memorize
under certain defined conditions, and see how quickly and well he
learns it; then you give him another, equally difficult lesson to be
learned under altered conditions, and observe whether he {13} does
better or worse than before. Thus you discover which set of conditions
is more favorable for memorizing, and thence can infer something of
the way in which memorizing is accomplished. In the whole experiment
you need not have called on your subject for any introspections; and
this is a type of many experiments in which the subject accomplishes a
certain task under known conditions, and his success is objectively
observed and measured.

There is another type of objective psychological observation, directed
not towards the success with which a task is accomplished, but towards
the changes in breathing, heart beat, stomach movements, brain
circulation, or involuntary movements of the hands, eyes, etc., which
occur during the course of various mental processes, as in reading, in
emotion, in dreaming or waking from sleep.

Now it is not true as a matter of history that either of these types
of objective observation was introduced into psychology by those who
call themselves behaviorists. Not at all; experiments of both sorts
have been common in psychology since it began to be an experimental
science. The first type, the success-measuring experiment, has been
much more used than introspection all along. What the behaviorists
have accomplished is the definitive overthrow of the doctrine, once
strongly insisted on by the "consciousness psychologists", that
introspection is the only real method of observation in psychology;
and this is no mean achievement. But we should be going too far if we
followed the behaviorists to the extent of seeking to exclude
introspection altogether, and on principle. There is no sense in such
negative principles. Let us accumulate psychological facts by any
method that will give the facts.

{14}

General Laws of Psychological Investigation.

Either introspective or objective observation can be employed in the
_experimental attack_ on a problem, which consists, as just
illustrated in the case of memory, in controlling the conditions under
which a mental performance occurs, varying the conditions
systematically, and noting the resulting change in the subject's
mental process or its outcome. Psychologists are inclined to regard
this as the best line of attack, whenever the mental activity to be
studied can be effectively subjected to control. Unfortunately,
emotion and reasoning are not easily brought under control, and for
this reason psychology has made slower progress in understanding them
than it has made in the fields of sensation and memory, where good
experimental procedure has been developed.

Another general line of attack worthy to be mentioned alongside of the
experimental is the _comparative method_. You compare the actions of
individuals, classes or species, noting likenesses and differences.
You see what behavior is typical and what exceptional. You establish
norms and averages, and notice how closely people cluster about the
norm and how far individuals differ from it. You introduce tests of
various sorts, by which to get a more precise measure of the
individual's performance. Further, by the use of what may be called
double comparison, or "correlation", you work out the relationships of
various mental (and physical) traits. For example, when many different
species of animals are compared in intelligence and also in brain
weight, the two are found to correspond fairly well, the more
intelligent species having on the whole the heavier brains; from which
we fairly conclude that the size of the brain has something to do with
intelligence. But when we correlate brain weight and intelligence in
human individuals. {15} we find so many exceptions to the rule (stupid
men with large brains and gifted men with brains of only moderate
size) that we are forced to recognize the importance of other factors,
such as the perfection of the microscopic structure of the brain.

Tests and correlations have become so prominent in recent
psychological investigation that this form of the comparative method
ranks on a par with the strict experimental method. A test is an
experiment, in a way, and at least is often based upon an experiment;
but the difference between the two lines of attack is that an
experiment typically takes a few subjects into the laboratory and
observes how their mental performances change with planfully changed
conditions; whereas a test goes out and examines a large number of
persons under one fixed set of conditions. An experiment belongs under
what we called "general psychology", and a test under "differential
psychology", since the first outcome of a test is to show how the
individual differs from others in a certain respect. The results may,
however, be utilized in various ways, either for such practical
purposes as guiding the individual's choice of an occupation, or for
primarily scientific purposes, such as examining whether intelligence
goes with brain size, whether twins resemble each other as much
mentally as they do physically, whether intellectual ability and moral
goodness tend on the whole to go together, or not.

The _genetic method_ is another of the general lines of attack on
psychological problems. The object here is to trace the mental
development of the individual, or of the race. It may be to trace the
development either of mentality in general, or of some particular
mental performance. It may be to trace the child's progress in
learning to speak, or to follow the development of language in the
human species, from the most primitive tongues up to those of the
great {16} civilized peoples of to-day. It may be to trace the
improvement of a performance with continued practice.

The value of the genetic method is easily seen. Usually the beginnings
of a function or performance are comparatively simple and easy to
observe and analyze. Also, the process of mental growth is an
important matter to study on its own account.

The _pathological method_ is akin to the genetic, but traces the decay
or demoralization of mental life instead of its growth. It traces the
gradual decline of mental power with advancing age, the losses due to
brain disease, and the maladaptations that appear in insanity and
other disturbances. Here psychology makes close contact with
_psychiatry_ which is the branch of medicine concerned with the
insane, etc., and which in fact has contributed most of the
psychological information derived from the pathological method.

The object of the pathological method is, on the one side, to
understand abnormal forms of mental life, with the practical object of
preventing or curing them, and on the other side, to understand normal
mental life the better. Just as the development of a performance
throws light on the perfected act, so the decay or disturbance of a
function often reveals its inner workings; for we all know that it is
when a machine gets out of order that one begins to see how it ought
to work. Failure sheds light on the conditions of success,
maladaptation throws into relief the mental work that has to be done
by the normal individual in order to secure and maintain his good
adaptation. According to the psychiatrists, mental disturbance is
primarily an affair of emotion and desire rather than of intellect;
and consequently they believe that the pathological method is of
special importance in the study of the emotional life.

{17}

Summary and Attempt at a Definition

Having now made a rapid preliminary survey of the field of psychology,
and of the aims and methods of the workers in this field, we ought to
be in a position to give some sort of a definition.

We conclude, then: psychology is a part of the scientific study of
life, being the science of mental life. Life consisting in process or
action, psychology is the scientific study of mental processes or
activities. A mental activity is typically, though not universally,
conscious; and we can roughly designate as mental those activities of
a living creature that are either conscious themselves or closely akin
to those that are conscious. Further, any mental activity can also be
regarded as a physiological activity, in which case it is analyzed
into the action of bodily organs, whereas as "mental" it simply comes
from the organism or individual as a whole. Psychology, in a word, is
the science of the conscious and near-conscious activities of living
individuals.

Psychology is not interested either in dead bodies or in disembodied
spirits, but in living and acting individuals.

One word more, on the _psychological point of view_. In everyday life
we study our acquaintances and their actions from a personal
standpoint. That is, we evaluate their behavior according as it
affects ourselves, or, perhaps, according as it squares or not with
our standards of right and wrong. We always find something to praise
or blame. Now, the psychologist has no concern with praise and blame,
but is a seeker after the facts. He would know and understand human
actions, rather than pass judgment on them. When, for example, he is
introduced into the school or children's court, for the purpose of
examining children that are "problems", his attitude differs
considerably from that of the {18} teacher or officer of the law; for
while they almost inevitably pass judgment on the child in the way of
praise or blame, the psychologist simply tries to understand the
child. The young delinquent brought into the laboratory of the court
psychologist quickly senses the unwonted atmosphere, where he is
neither scolded nor exhorted, but asked to lend his cooeperation in an
effort to discover the cause why his conduct is as it is. Now, this
psychological attitude is not necessarily "better" than the other, but
it is distinctly valuable in its place, as seen from the fact that the
young delinquent often does cooeperate. He feels that if the
psychologist can find out what is the trouble with him, this may help.
Nothing, indeed, is more probable; it is when we have the facts and
trace out cause and effect that we are in a fair way to do good.
Nothing is more humane than psychology, in the long run, even though
the psychologist may seem unfeeling in the course of his
investigation.

To the psychologist, conduct is a matter of cause and effect, of
natural law. His business is to know the laws of that part of nature
which we call human nature, and to use these laws, as fast as
discovered, for solving the problems presented by the human individual
or group. For him, even the most capricious conduct has its causes,
even the most inexplicable has its explanation--if only the cause can
be unearthed, which he does not pretend he can always actually
accomplish, since causes in the mental realm are often very complex.
No one can be a psychologist all of the time; no one can or should
always maintain this matter-of-fact attitude towards self and
neighbor. But some experience with the psychological attitude is of
practical value to any one, in giving clearer insight, more
toleration, better control, and even saner standards of living.

{19}

EXERCISES

1. Outline the chapter. A sample outline of the briefer sort is
   here given:

A. Subject-matter of psychology: mental activities.

  (1) A sub-class under vital activities.

  (2) Activities of individuals, as distinguished from

    (a) Activities of social groups (sociology).

    (b) Activities of single organs (physiology).

 (3) Either conscious, or closely related to conscious activities.

 (4) May be activities of human or animal, adult or child,
     normal or abnormal individuals.

B. Problems of psychology:

 (1) How individuals differ in their mental activities.

 (2) How individuals are alike in their mental activities.

 (3) Practical applications of either (1) or (2).

C. Methods of psychology:

 (1) Methods of observing mental activities.

   (a) Introspective, the observing by an individual of his own actions.

   (b) Objective, the observation of the behavior of other individuals.

 (2) General lines of attack upon psychological problems.

   (a) Experimental: vary the conditions and see how the mental
       activity changes.

   (b) Comparative: test different individuals or
       classes and see how mental activity differs, etc.

   (c) Genetic: trace mental development.

   (d) Pathological: examine mental decay or disturbance.

2. Formulate a psychological question regarding each of the following:
   hours of work, genius, crime, baseball.

3. Distinguish introspection from theorizing.

4. What different sorts of objective fact can be observed in psychology?

5. What is the difference between the physiology of hearing and the
   psychology of hearing?

6. State two reasons why it would be undesirable to limit psychology
   to the introspective study of consciousness.

{20}

7. What is the difference between an experiment and a test, (a) in
   purpose, (b) in method?

8. Compare the time it takes you to add twenty one-place numbers,
   arranged in a vertical column, and arranged in a horizontal line,
   (a) Is this introspective or objective observation? Why so? (b) Is
   it a test or an experiment? Why?

9. Write a psychological sketch of some one you know well, taking
   care to avoid praise and blame, and to stick to the psychological
   point of view.



REFERENCES

Some of the good books on the different branches of psychology are
the following:

On animal psychology:

  Margaret F. Washburn, _The Animal Mind_, 2nd edition, 1917.

  John B. Watson, _Behavior_, 1914.

On child psychology:

  Norsworthy and Whitley, _The Psychology of Childhood_, 1918.

On abnormal psychology:

  A. J. Rosanoff, _Manual of Psychiatry_, 5th edition, 1920.

On applied psychology:

  Hollingworth and Poffenberger, _Applied Psychology_, 1917.

On individual psychology, parts of:

  E. L. Thorndike, _Educational Psychology, Briefer Course_, 1914,

  Daniel Starch, _Educational Psychology_, 1919.



{21}

CHAPTER II

REACTIONS

REFLEXES AND OTHER ELEMENTARY FORMS OF REACTION,
AND HOW THE NERVES OPERATE IN CARRYING THEM OUT

Having the field of psychology open before us, the next question is,
where to commence operations. Shall we begin with memory, imagination
and reasoning, or with will, character and personality, or with motor
activity and skill, or with feelings and emotions, or with sensation
and perceptions? Probably the higher forms of mental activity seem
most attractive, but we may best leave complicated matters till later,
and agree to start with the simplest sorts of mental performance. Thus
we may hope to learn at the outset certain elementary facts which will
later prove of much assistance in unraveling the more complex
processes.

Among the simplest processes are sensations and reflexes, and we might
begin with either. The introspective psychologists usually start with
sensations, because their great object is to describe consciousness,
and they think of sensations as the chief elements of which
consciousness is composed. The behaviorists would prefer to start with
reflexes, because they conceive of behavior as composed of these
simple motor reactions.

Without caring to attach ourselves exclusively to either
introspectionism or behaviorism, we may take our cue just here from
the behaviorists, because we shall find the facts of motor reaction
more widely useful in our further studies than the facts of sensation,
and because the facts of  {22} sensation fit better into the general
scheme of reactions than the facts of reaction fit into any general
scheme based on sensation.

A reaction is a _response_ to a _stimulus_. The response, in the
simplest cases, is a muscular movement, and is called a "motor
response". The stimulus is any force or agent that, acting upon the
individual, arouses a response.

If I start at a sudden noise, the noise is the stimulus, and the
forcible contraction of my muscles is the response. If my old friend's
picture brings tears to my eyes, the picture (or the light reflected
from it) is the stimulus, and the flow of tears is the response, here
a "glandular" instead of a motor response.


The Reaction Time Experiment

One of the earliest experiments to be introduced into psychology was
that on reaction time, conducted as follows: The experimenter tells
his "subject" (the person whose reaction is to be observed) to be
ready to make a certain movement as promptly as possible on receiving
a certain stimulus. The response prescribed is usually a slight
movement of the forefinger, and the stimulus may be a sound, a flash
of light, a touch on the skin, etc. The subject knows in advance
exactly what stimulus is to be given and what response he has to make,
and is given a "Ready!" signal a few seconds before the stimulus. With
so simple a performance, the reaction time is very short, and delicate
apparatus must be employed to measure it. The "chronoscope" or clock
used to measure the reaction time reads to the hundredth or thousandth
of a second, and the time is found to be about .15 sec. in responding
to sound or touch, about .18 sec. in responding to light.

Even the simple reaction time varies, however, from one {23}
individual to another, and from one trial to another. Some persons can
never bring their record much below the figures stated, while a few
can get the time down to .10 sec, which is about the limit of human
ability. Every one is bound to vary from trial to trial, at first
widely, after practice between narrow limits, but always by a few
hundredths of a second at the least. It is curious to find the
elementary fact of variability of reaction present in such a simple
performance.

What we have been describing is known as the "simple reaction", in
distinction from other experiments that demand more of the subject. In
the "choice reaction", there are two stimuli and the subject may be
required to react to the one with the right hand and to the other with
the left; for example, if a red light appears he must respond with the
right hand, but if a green light appears, with the left. Here he
cannot allow himself to become keyed up to as high a pitch as in the
simple reaction, for if he does he will make many false reactions.
Therefore, the choice reaction time is longer than the simple reaction
time--about a tenth of a second longer.

The "associative reaction" time is longer still. Here the subject must
name any color that is shown, or read any letter that is shown, or
respond to the sight of any number by calling out the next larger
number, or respond to any suitable word by naming its opposite. He
cannot be so well prepared as for the simple, or choice reaction,
since he doesn't know exactly what the stimulus is going to be; also,
the brain process is more complex here; so that the reaction time is
longer, about a tenth of a second longer, at the best, than the choice
reaction. It may run up to two or three seconds, even in fairly simple
cases, while if any serious thinking or choosing has to be done, it
runs into many seconds and even into minutes. Here the brain process
is very {24} complex and involves a series of steps before the
required motor response can be made.

These laboratory experiments can be paralleled by many everyday
performances. The runner starting at the pistol shot, after the
preparatory "Ready! Set!", and the motorman applying the brakes at the
expected sound of the bell, are making "simple" reactions. The boxer,
dodging to the right or the left according to the blow aimed at him by
his adversary, is making choice reactions, and this type is very
common in all kinds of steering, handling tools and managing
machinery. Reading words, adding numbers, and a large share of simple
mental performances, are essentially associative reactions. In most
cases from ordinary life, the _preparation_ is less complete than in
the laboratory experiments, and the reaction time is accordingly
longer.


Reflex Action

The simple reaction has some points of resemblance with the "reflex",
which, also, is a prompt motor response to a sensory stimulus. A
familiar example is the reflex wink of the eyes in response to
anything touching the eyeball, or in response to an object suddenly
approaching the eye. This "lid reflex" is quicker than the quickest
simple reaction, taking about .05 second. The knee jerk or "patellar
reflex", aroused by a blow on the patellar tendon just below the knee
when the knee is bent and the lower leg hanging freely, is quicker
still, taking about .03 second. The reason for this extreme quickness
of the reflex will appear as we proceed. However, not every reflex is
as quick as those mentioned, and some are slower than the quickest of
the simple reactions.

A few other examples of reflexes may be given. The "pupillary reflex"
is the narrowing of the pupil of the eye {25} in response to a bright
light suddenly shining into the eye. The "flexion reflex" is the
pulling up of the leg in response to a pinch, prick or burn on the
foot. Coughing and sneezing are like this in being protective
reflexes, and the scratching of the dog belongs here also.

There are many internal reflexes: movements of the stomach and
intestines, swallowing and hiccoughing, widening and narrowing of the
arteries resulting in flushing and paling of the skin. These are
muscular responses; and there are also glandular reflexes, such as the
discharge of saliva from the salivary glands into the mouth, in
response to a tasting substance, the flow of the gastric juice when
food reaches the stomach, the flow of tears when a cinder gets into
the eye. There are also inhibitory reflexes, such as the momentary
stoppage of breathing in response to a dash of cold water. All in all,
a large number of reflexes are to be found.

Most reflexes can be seen to be _useful_ to the organism. A large
proportion of them are protective in one way or another, while others
might be called regulative, in that they adjust the organism to the
conditions affecting it.

Now comparing the reflex with the simple reaction, we see first that
the reflex is more deep-seated in the organism, and more essential to
its welfare. The reflex is typically quicker than the simple reaction.
The reflex machinery does not need a "Ready" signal, nor any
preparation, but is always ready for business. (The subject in a
simple reaction experiment would not make the particular finger
movement that he makes unless he had made ready for that movement.)
The attachment of a certain response to a certain stimulus, rather
arbitrary and temporary in the simple reaction, is inherent and
permanent in the reflex. Reflex action is involuntary and often
entirely unconscious.

Reflexes, we said, are permanent. That is because they {26} are native
or inherent in the organism. You can observe them in the new-born
child. The reflex connection between stimulus and response is
something the child brings with him into the world, as distinguished
from what he has to acquire through training and experience. He does
acquire, as he grows up, a tremendous number of habitual responds that
become automatic and almost unconscious, and these "secondary
automatic" reactions resemble reflexes pretty closely. Grasping for
your hat when you feel the wind taking it from your head is an
example. These acquired reactions never reach the extreme speed of the
quickest reflexes, but at best may have about the speed of the simple
reaction. Though often useful enough, they are not so fundamentally
necessary as the reflexes. The reflex connection of stimulus and
response is something essential, native, closely knit, and always
ready for action.


The Nerves in Reflex Action

Seeing that the response, in reflex action, is usually made by a
muscle or gland lying at some distance from the sense organ that
receives the stimulus--as, in the case of the flexion reflex, the
stimulus is applied to the skin of the hand (or foot), while the
response is made by muscles of the limb generally--we have to ask what
sort of connection exists between the stimulated organ and the
responding organ, and we turn to physiology and anatomy for our
answer. The answer is that the _nerves_ provide the connection. Strands
of nerve extend from the sense organ to the muscle.

But the surprising fact is that the nerves do not run directly from
the one to the other. There is no instance in the human body of a
direct connection between any sense organ and any muscle or gland. The
nerve path from sense organ to muscle always leads through a _nerve
center_. One {27} nerve, called the sensory nerve, runs from the sense
organ to the nerve center, and another, the motor nerve, runs from the
center to the muscle; and the only connection between the sense organ
and the muscle is this roundabout path through the nerve center. The
path consists of three parts, sensory nerve, center, and motor nerve,
but, taken as a whole, it is called the _reflex arc_, both the words,
"reflex" and "arc", being suggested by the indirectness of the
connection.


[Illustration: Fig. 1.--The connection from the back of the hand,
which is receiving a stimulus, and the arm muscle which makes the
response. The nerve center is indicated by the dotted lines.]


The _nervous system_ resembles a city telephone system. What passes
along the nerve is akin to the electricity that {28} passes along the
telephone wire; it is called the "nerve current", and is electrical
and chemical in nature.


[Illustration: Fig. 2.--(From Martin's "Human Body.") General view of
the nervous system, showing brain, cord, and nerves.]


All nerve connections, like the great majority of telephone
connections, are effected through the centers, called "centrals" in
{29} the case of the telephone. Telephone A is connected directly with
the central, telephone B likewise, and A and B are indirectly
connected, through the central switchboard. That is the way it is in
the nervous system, with "nerve center" substituted for "central", and
"sense organ" and "muscle or gland" for "telephones A and B."


[Illustration: Fig. 3.--Location of the cord, cerebrum and cerebellum.
The brain stem continues the cord upward into the skull cavity.
(Figure text: cerebrum, cerebellum, cord, tongue)]


The advantage of the centralized system is that it is a _system_,
affording connections between any part and any other, and unifying the
whole complex organism.

The _nerve centers_ are located in the brain and spinal cord. The
brain lies in the skull and the cord extends from the brain down
through a tube in the middle of the {30} backbone. Of the brain many
parts can be named, but for the present it is enough to divide it into
the "brain stem", a continuation of the spinal cord up along the base
of the skull cavity, and the two great outgrowths of the brain stem,
called "cerebrum" and "cerebellum". The spinal cord and brain stem
contain the lower or reflex centers, while the cerebellum, and
especially the cerebrum, contain the "higher centers". The lower
centers are directly connected by nerves with the sense organs, glands
and muscles, while the higher centers have direct connections with the
lower and only through them with the sense organs, glands and muscles.
In other words, the sensory nerves run into the cord or brain stem,
and the motor nerves run out of these same, while interconnecting
nerve strands extend between the lower centers in the cord and brain
stem and the higher centers in the cerebrum and cerebellum.

The spinal cord contains the reflex centers for the limbs and part of
the trunk, and is connected by sensory and motor nerves with the limbs
and trunk. The brain stem contains the reflex centers for the head and
also for part of the interior of the trunk, including the heart and
lungs, and is connected with them by sensory and motor nerves. The
nerve center that takes part in the flexion reflex of the foot is
situated in the lower part of the cord, that for the similar reflex of
the hand lies in the upper part of the cord, that for breathing lies
in the lower or rear part of the brain stem, and that for winking lies
further forward in the brain stem.

Big movements, such as the combined action of all four legs of an
animal in walking, require cord and brain stem to work together, and
throw into relief what is really true even of simpler reflexes, namely
that a reflex is a _coordinated_ movement, in the sense that different
muscles cooperate in its execution.

{31}

Internal Construction of the Nerves and Nerve Centers

We shall understand nerve action better if we know something of the
way in which the nervous system is built. A nerve is not to be thought
of as a unit, nor are the brain and cord to be thought of as mere
masses of some peculiar substance.


[Illustration: Fig. 4.--A motor nerve cell from the spinal cord,
highly magnified. (Figure text: dendrites, cell body, axon,
termination of axon in muscle)]


A nerve is a bundle of many slender insulated threads, just as a
telephone cable, running along the street, {32} is a bundle of many
separate wires which are the real units of telephonic communication. A
nerve center, like the switchboard in a telephone central, consists of
many parts and connections.

The whole nervous system is essentially composed of _neurones_. A
neurone is a nerve cell with its branches. Most nerve cells have two
kinds of branches, called the _axon_ and the _dendrites_.

The nerve cell is a microscopic speck of living matter. Its dendrites
are short tree-like branches, while its axon is often several inches
or even feet in length. The axon is the "slender thread", just spoken
of as analogous to the single telephone wire. A nerve is composed of
axons. [Footnote: The axon is always protected or insulated by a
sheath, and axon and sheath, taken together, are often called a "nerve
fiber".] The "white matter" of the brain and cord is composed of
axons. Axons afford the means of communication between the nerve
centers and the muscles and sense organs, and between one nerve center
and another.

The axons which make up the motor nerves are branches of nerve cells
situated in the cord and brain stem; they extend from the reflex
center for any muscle out to and into that muscle and make very close
connection with the muscle substance. A nerve current, starting from
the nerve cells in the reflex center, runs rapidly along the axons to
the muscle and arouses it to activity.

The axons which make up the optic nerve, or nerve of sight, are
branches of nerve cells in the eye, and extend into the brain stem.
Light striking the eye starts nerve currents, which run along these
axons into the brain stem. Similarly, the axons of the nerve of smell
are branches of cells in the nose.

The remainder of the sensory axons are branches of nerve cells that
lie in little bunches close alongside the cord or {33} brain stem.
These cells have no dendrites, but their axon, dividing, reaches in
one direction out to a sense organ and in the other direction into the
cord or brain stem, and thus connects the sense organ with its "lower
center".


[Illustration: Fig. 5.--Sensory and motor axons, and their nerve
cells. The arrows indicate the direction of conduction. (Figure text:
eye, brain stem, skin, cord, muscle)]


Where an axon terminates, it broadens out into a thin plate, or breaks
up into a tuft of very fine branches ( the "end-brush"), and by this
means makes close contact with the muscle, the sense organ, or the
neurone with which it connects.

{34}

The Synapse

Now let us consider the mode of connection between one neurone and
another in a nerve center. The axon of one neurone, through its
end-brush, is in close contact with the dendrites of another neurone.
There is contact, but no actual growing-together; the two neurones
remain distinct, and this contact or junction of two neurones is
called a "synapse". The synapse, then, is not a thing, but simply a
junction between two neurones.


[Illustration: Fig. 6.--The synapse between the two neurones lies just
above the arrow.]

The junction is good enough so that one of the two neurones, if itself
active, can arouse the other to activity. The end-brush, when a nerve
current reaches it from its own nerve cell, arouses the dendrites of
the other neurone, and thus starts a nerve current running along those
dendrites to their nerve cell and thence out along its axon.

Now here is a curious and significant fact: the dendrites are
receiving organs, not transmitting; they pick up messages from the
end-brushes across the synapse, but send out no messages to those
end-brushes. Communication across a synapse is always in one
direction, from end-brush to dendrites.

This, then, is the way in which a reflex is carried out, the pupillary
reflex, for example. Light entering the eye starts a nerve current in
the axons of the optic nerve; these axons terminate in the brain stem,
where their end-brushes arouse the dendrites of motor nerve cells, and
the axons of these {35} cells, extending out to the muscle of the
pupil, cause it to contract, and narrow the pupil.

Or again, this is the way in which one nerve center arouses another to
activity. The axons of the cells in the first center (or some of them)
extend out of this center and through the white matter to the second
center, where they terminate, their end-brushes forming synapses with
the cells of the second center. Let the first center be thrown into
activity, and immediately, through this connection, it arouses the
second.


[Illustration: Fig. 7.--Different forms of synapse found in the
cerebellum, "a" is one of the large motor cells of the cerebellum (a
"Purkinje cell"), with its dendrites above and its axon below; and
"b," "c" and "d" show three forms of synapse made by other neurones
with this Purkinje cell. In "b," the arrow indicates a "climbing
axon," winding about the main limbs of the Purkinje cell. In "c," the
arrow points to a "basket"--an end-brush enveloping the cell body;
while "d" shows what might be called a "telegraph-wire synapse."
Imagine "d" superimposed upon "a": the axon of "d" rises among the
fine dendrites of "a," and then runs horizontally through them; and
there are many, many such axons strung among the dendrites. Thus the
Purkinje cell is stimulated at three points: cell body, trunks of the
dendrites, and twigs of the dendrites.]


The "gray matter" comprises the nerve centers, lower and higher. It is
made up of nerve cells and their dendrites, of the beginnings of axons
issuing from these cells and of the terminations of incoming axons.
The white matter, as was said before, consists of axons. An axon
issues from the {36} gray matter at one point, traverses the white
matter for a longer or shorter distance, and finally turns into the
gray matter at another point, and thus nerve connection is maintained
between these two points.

There are lots of nerve cells, billions of them. That ought to be
plenty, and yet--well, perhaps sometimes they are not well developed,
or their synapses are not close enough to make good connections.


[Illustration: Fig. 8.--A two-neurone reflex arc. (Figure text:
stimulus, skin, sensory axon, bit of the spinal cord, motor axon,
muscle)]


Examined under the microscope, the nerve cell is seen to contain,
besides the "nucleus" which is present in every living cell and is
essential for maintaining its vitality and special characteristics,
certain peculiar granules which appear to be stores of fuel to be
consumed in the activity of the cell, and numerous very fine fibrils
coursing through the cell and out into the axon and dendrites.

The _reflex arc can now be described_ more precisely than before.
Beginning in a sense organ, it extends along a sensory axon (really
along a team of axons acting side by side) to its end-brush in a lower
center, where it crosses a synapse and enters the dendrites of a motor
neurone and so {37} reaches the cell body and axon of this neurone,
which last extends out to the muscle (or gland). The simplest reflex
arc consists then of a sensory neurone and a motor neurone, meeting at
a synapse in a lower or reflex center. This would be a two-neurone
arc.


[Illustration: Fig. 9.--A three-neurone arc, concerned in respiration.
This also illustrates how one nerve center influences another.
(Figure text:  white matter, gray matter, lung, respiratory center in
the brain stem, diaphragm, motor center in cord for the diaphragm)]


Very often, and possibly always, the reflex arc really consists of
three neurones, a "central" neurone intervening between the sensory
and motor neurones and being connected through synapses with each. The
central neurone plays an important role in cooerdination.


COOeRDINATION

The internal structure of nerve centers helps us see how cooerdinated
movement is produced. The question is, how {38} several muscles are
made to work together harmoniously, and also how it is possible that a
pin prick, directly affecting just a few sensory axons, causes a big
movement of many muscles. Well, we find the sensory axon, as it enters
the cord, sending off a number of side branches, each of which
terminates in an end-brush in synaptic connection with the dendrites
of a motor nerve cell.


[Illustration: Fig. 10.--Cooerdination brought about by the branching
of a sensory axon. (Figure text: cord, sensory neurone, motor neurone)]


Thus the nerve current from a single sensory neurone is distributed to
quite a number of motor neurones. Where there are central neurones in
the arc, their branching axons aid in distributing the excitation; and
so we get a big movement in response to a minute, though intense
stimulus.

But the response is not simply big; it is definite, coordinated,
representing team work on the part of the muscles as distinguished
from indiscriminate mass action. That means selective distribution of
the nerve current. The axons of the sensory and central neurones do
not connect with any and every motor neurone indiscriminately, but
link up with selected groups of motor neurones, and thus harness
together teams that will work in definite ways, producing {39} flexion
of a limb in the case of one such team, and extension in the case of
another. Every reflex has its own team of motor neurones, harnessed
together by its outfit of sensory and central neurones. The same motor
neurone may however be harnessed into two or more such teams, as is
seen from the fact that the same muscle may participate in different
reflex movements; and for a similar reason we believe that the same
sensory neurone may be utilized in more than one reflex arc.


[Illustration: Fig. 11.--Cooerdination brought about by the branching
of the axon of a central neurone. (Figure text: sensory, central,
motor)]


The most distinctive part of any reflex arc is likely to be its
central neurones, which are believed to play the chief part in
cooerdination, and in determining the peculiarities of any given
reflex, such as its speed and rhythm of action.


Reactions in General

Though the reflex is simple by comparison with voluntary movements, it
is not the simplest animal reaction, for it is cooerdinated and depends
on the nervous system, while the simplest animals, one-celled animals,
have no nervous system, any more than they have muscles or organs of
any {40} kind. Without possessing separate organs for the different
vital functions, these little creatures do nevertheless take in and
digest food, reproduce their kind, and move. Every animal shows at
least two different motor reactions, a positive or approaching
reaction, and a negative or avoiding reaction.

The general notion of a reaction is that of a _response_ to a
_stimulus_. The stimulus acts on the organism and the organism acts
back. If I am struck by a wave and rolled over on the beach, that is
passive motion and not my reaction; but if the wave stimulates me to
maintain my footing, then I am active, I respond or react.

Now there is no such thing as wholly passive motion. Did not Newton
teach that "action and reaction are equal"?--and he was thinking of
stones and other inanimate objects. The motion of a stone or ball
depends on its own weight and shape and elasticity as much as on the
blow it receives. Even the stone counts for something in determining
its own behavior.

A loaded gun counts for more than a stone, because of the stored
energy of the powder that is set free by the blow of the hammer. The
"reaction" of the gun is greater than the force acting on it, because
of this stored energy that is discharged.

An animal reaction resembles the discharge of the gun, since there is
stored energy in the animal, consisting in the chemical attraction
between food absorbed and oxygen inspired, and some of this energy is
utilized and converted into motion when the animal reacts. The
stimulus, like the trigger of the gun, simply releases this stored
energy.

The organism, animal or human, fully obeys the law of conservation of
energy, all the energy it puts out being accounted for by stored
energy it has taken in in food and oxygen. But at any one time, when
the organism receives {41} a stimulus, the energy that it puts forth
in reaction comes from inside itself.

There is another way in which the organism counts in determining its
reaction. Not only does it supply the energy of the response, but its
own internal arrangements determine how that energy shall be directed.
That is to say, the organism does not blow up indiscriminately, like a
charge of dynamite, but makes some definite movement. This is true
even of the simplest animals, and the more elaborate the internal
mechanism of the animal, the more the animal itself has to do with the
kind of response it shall make to a stimulus. The nervous system of
the higher animals, by the connections it provides between the
stimulus and the stores of energy in the muscles, is of especial
importance in determining the nature of the response.

Stimuli are necessary to arouse the activity of the organism. Without
any stimulus whatever, it seems likely that the animal would relapse
into total inactivity. It should be said, however, that stimuli, such
as that of hunger, may arise within the organism itself. The stimulus
may be external or internal, but some stimulus is necessary in order
to release the stored energy.

In general, then, a reaction consists in the release by a stimulus of
some of the stored energy of an animal, and the direction of that
energy by the animal's own internal mechanism of nerves and muscles
(and, we may add, bones and sinews) into the form of some definite
response.

{42}

EXERCISES

1. Outline of the chapter, being at the same time a "completion
   test". Complete the following outline by filling in the blank
   spaces (usually a single word will fill the blank, but sometimes two
   words will be better):

   A. Definition: A reaction is a response to a ___________.
      The stimulus energy stored in the organism, and the __________
      has a definite form determined by the organism's own machinery
      of ________ and ______.



   B. Among very prompt reactions are the reflex and the "simple
      reaction". The reflex differs from the "simple reaction" in that:

      (1) It usually takes less________.

      (2) It requires no___________,

      (3) The machinery for it is ________in the organism.

   C. The machinery for a reflex consists of:

      (1) a________ organ.

      (2) a ________nerve.

      (3) a nerve ________,

      (4) a _________nerve.

      (5) a muscle or _________.

   D. The sensory and motor nerves consist of ________ which are
      branches of ______. The cells for the motor nerves lie in the
      ________, and those for the sensory nerves lie in two cases in
      the _________, and in all other cases in bunches located close
      beside the _________or ________,

   E. The neurone is the _______ of which the nervous ______ is
      composed. It consists of a ________ and of two sorts of
      branches, the ________ and the ________. Internally, the neurone
      shows a peculiar structure of ________ and ________.

   F. Communication from one neurone to another occurs across
      a _____ called the synapse. The _________of an axon here comes
      into close contact with the ______or with the _________of
      another neurone. The communication takes place from the
      ________of the first neurone to the ___________ of the second.

   G. The "nerve current" in a reflex therefore runs the following
      course: from the sense organ into a ________ axon, along this to
      its _________ in a nerve, and across a _________ there into the
      _________ of a neurone, and thence {43} out along the _______of
      this neurone to the ________or _________ that executes the
      reflex. This is a two-neurone _________, but often there is a
      third, ________neurone between the _________ and the
      _____________.

   H. Cooerdination is effected by the ________ of the axons of the
      sensory and ________ neurones, by which means the nerve current
      is ______ to a team of ________  and so to a team of _________.

2. Is the reaction time experiment, as described in the text, an
   introspective or an objective experiment?

3. Mention two cases from common life that belong under the
   "simple reaction", two that belong under "choice reaction", and two
   that belong under the "associative reaction".

4. Arrange the reflexes mentioned in the text under the two heads
   of "protective" and "regulative".

5. Draw diagrams of (a) the neurone, (b) a synapse, (c) a reflex
   arc, and (d) a cooerdinated movement. Reduce each drawing to the
   simplest possible form, and still retain everything that is
   essential.

6. What part of the nervous system lies (a) in the forehead and
   top of the head, (b) in the very back of the head, (c) along the
   base of the skull, (d) within the backbone, (e) in the arm?

7. Using a watch to take the time, see how long it takes you to
   name the letters in a line of print, reading them in reverse order
   from the end of the line to the beginning. Compare with this time
   the time required to respond to each letter by the letter following
   it in the alphabet (saying "n" when you see m, and "t" when you see
   s, etc.). Which of these two "stunts" is more like reflex action,
   and how, nevertheless, does it differ from true reflex action?

8. The pupillary reflex. Describe the reaction of the pupil of the
   eye to light suddenly shining into the eye. This response can best
   be observed in another person, but you can observe it in yourself
   by aid of a hand mirror. On another person you can also observe the
   "crossed" pupillary reflex, by throwing the light into one eye only
   while you watch the other eye. What sort of connection do you
   suppose to exist between the two eyes, making this crossed reflex
   possible?

9. The lid reflex, or wink reflex, (a) Bring your hand suddenly
   close to another person's eye, and notice the response of the
   eyelid, (b) See whether you can get a crossed reflex here, (c) See
   whether your subject can voluntarily prevent (inhibit) the lid
   reflex, (d) See whether the reflex occurs when he gives the
   stimulus himself, by moving his own hand suddenly up to his eye.
   (e) What other stimulus, besides the visual one that you have been
   using, will arouse the same response?

{44}

REFERENCES

C. Judson Herrick, in his _Introduction to Neurology_, 2nd edition,
1918, gives a fuller and yet not too detailed account of the neurone
in Chapter III, and of reflex action in Chapter IV.

Percy G. Stiles, in his _Nervous System and Its Conservation_, 1915,
discusses these matters in Chapters II, III and IV.

Ladd and Woodworth's _Elements of Physiological Psychology_, 1911, has
chapters on these topics.

{45}


CHAPTER III

REACTIONS OF DIFFERENT LEVELS

HOW SENSATIONS, PERCEPTIONS AND THOUGHTS MAY BE CONSIDERED AS FORMS OF
INNER RESPONSE, AND HOW THESE HIGHER REACTIONS ARE RELATED IN THE
NERVOUS SYSTEM TO THE SIMPLER RESPONSES OF THE REFLEX LEVEL.

Having defined a reaction as an act of the individual aroused by a
stimulus, there is no reason why we should not include a great variety
of mental processes under the general head of reactions. Any mental
process is an activity of the organism, and it is aroused by some
stimulus, external or internal; therefore, it is a reaction.

I hear a noise--now, while the noise, as a physical stimulus, comes to
me, my hearing it is my own act, my sensory reaction to the stimulus.
I recognize the noise as the whistle of a steamboat--this recognition
is clearly my own doing, dependent on my own past experience, and may
be called a perception or perceptive response. The boat's whistle
reminds me of a vacation spent on an island--clearly a memory
response. The memory arouses an agreeable feeling--an affective
response, this may be called. In its turn, this may lead me to imagine
how pleasant it would be to spend another vacation on that island, and
to cast about for ways and means to accomplish this result--here we
have imagination and reasoning, aroused by what preceded just as the
sensation was aroused by the physical stimulus.

In speaking of any mental process as an act of the individual, we do
not mean to imply that he is always _conscious_ {46} of his activity.
Sometimes he feels active, sometimes passive. He feels active in hard
muscular work or hard thinking, while he feels passive in reflex
action, in sensation, and in simply "being reminded" of anything
without any effort on his own part. But he is active in everything he
does, and he does everything that depends on his being alive. Life is
activity, and every manifestation of life, such as reflex action or
sensation, is a form of vital activity. The only way to be inactive is
to be dead.

But vital activity is not "self-activity" in any absolute sense, for
it is _aroused_ by some stimulus. It does not issue from the
individual as an isolated unit, but is his _response_ to a stimulus.
That is the sense of calling any mental process a reaction; it is
something the individual does in response to a stimulus.

To call a sensation a form of reaction means, then, that the sensation
is not something done to the person, nor passively received by him
from outside, but something that he himself does when aroused to this
particular form of activity. What comes from outside and is received
by the individual is the stimulus, and the sensation is what he does
in response to the stimulus. It represents the discharge of internal
stored energy in a direction determined by his own inner mechanism.
The sensation depends on his own make-up as well as on the nature of
the stimulus, as is especially obvious when the sensation is abnormal
or peculiar. Take the case of color blindness. The same stimulus that
arouses in most people the sensation of red arouses in the color-blind
individual the sensation of brown. Now what the color-blind individual
_receives_, the light stimulus, is the same as what others receive,
but he responds differently, _i.e._, with a different sensation,
because his own sensory apparatus is peculiar.

The main point of this discussion is that all mental {47} phenomena,
whether movements, sensations, emotions, impulses or thoughts, are a
person's acts, but that every act is a response to some present
stimulus. This rather obvious truth has not always seemed obvious.
Some theorists, in emphasizing the spontaneity and "self-activity" of
the individual, have pushed the stimulus away into the background;
while others, fixing their attention on the stimulus, have treated the
individual as the passive recipient of sensation and "experience"
generally. Experience, however, is not received; it is lived, and that
means done; only, it is done in response to stimuli. The concept of
reaction covers the ground.

While speaking of sensations and thoughts as belonging under the
general head of reactions, it is well, however, to bear in mind that
all mental action tends to arouse and terminate in muscular and
glandular activity. A thought or a feeling tends to "express itself"
in words or (other) deeds. The motor response may be delayed, or
inhibited altogether, but the tendency is always in that direction.


Different Sorts of Stimuli

To call all mental processes reactions means that it is always in
order to ask for the stimulus. Typically, the stimulus is an external
force or motion, such as light or sound, striking on a sense organ.
There are also the internal stimuli, consisting of changes occurring
within the body and acting on the sensory nerves that are distributed
to the muscles, bones, lungs, stomach and most of the organs. The
sensations of muscular strain and fatigue, and of hunger and thirst,
are aroused by internal stimuli, and many reflexes are aroused in the
same way.

Such internal stimuli as these are like the better known external
stimuli in that they act upon sense organs; but it {48} seems
necessary to recognize another sort of stimuli which act directly on
the nerve centers in the brain. These may be called "central stimuli"
and so contrasted with the "peripheral stimuli" that act on any sense
organ, external or internal. To do this is to take considerable
liberty with the plain meaning of  "stimulus", and calls for
justification. What is the excuse for thus expanding the notion of a
stimulus?

The excuse is found in the frequent occurrence of mental processes
that are not directly aroused by any peripheral stimulus, though they
are plainly aroused by something else. Anything that arouses a thought
or feeling can properly be called its stimulus. Now it often happens
that a thought is aroused by another, just preceding thought; and it
seems quite in order to call the first thought the stimulus and the
second the response. A thought may arouse an emotion, as when the
thought of my enemy, suddenly occurring to mind, makes me angry; the
thought is then the stimulus arousing this emotional response.

If hearing you speak of Calcutta makes me think of India, your words
are the stimulus and my thought the response. Well, then, if I _think_
of Calcutta in the course of a train of thought, and next think of
India, what else can we say than that the thought of Calcutta acts as
a stimulus to arouse the thought of India as the response? In a long
train of thought, where A reminds you of B and B of C and C of D, each
of these items is, first, a response to the preceding, and, second, a
stimulus to the one following.

There is no special difficulty with the notion of "central stimuli"
from the physiological side. We have simply to think of one nerve
center arousing another by means of the tract of axons connecting the
two. Say the auditory center is aroused by hearing some one mention
your friend's name, {49} and this promptly calls up a mental picture
of your friend; here the auditory center has aroused the visual. What
happens in a train of thought is that first one group of neurones is
aroused to activity, and then this activity, spreading along the axons
that extend from this group of neurones to another, arouses the second
group to activity; and so on. The brain process may often be
exceedingly complex, but this simple scheme gives the gist of it.

The way nerve currents must go shooting around the brain from one
center or group of neurones to another, keeping it up for a long time
without requiring any fresh peripheral stimulus, is remarkable. We
have evidence of this sort of thing in a dream or fit of abstraction.
Likely enough, the series of brain responses would peter out after
awhile, in the absence of any fresh peripheral stimulus, and total
inactivity ensue. But response of one brain center to nerve currents
coming from another brain center, and not directly from any sense
organ, must be the rule rather than the exception, since most of the
brain neurones are not directly connected with any sense organ, but
only with other parts of the brain itself. All the evidence we have
would indicate that the brain is not "self-active", but only
responsive; but, once thrown into activity at one point, it may
successively become active at many other points, so that a long series
of mental operations may follow upon a single sensory stimulus.


The Motor Centers, Lower and Higher

A "center" is a collection of nerve cells, located somewhere in the
brain or cord, which gives off axons running to some other center or
out to muscles or glands, while it also receives axons coming from
other centers, or from sense organs. These incoming axons terminate in
end-brushes and so form synapses with the dendrites of the local {50}
nerve cells. The axons entering any center and terminating there
arouse that center to activity, and this activity, when aroused, is
transmitted out along the axons issuing from that center, and produces
results where those axons terminate in their turn.


[Illustration: Fig. 12.--Side view of the left hemisphere of the
brain, showing the motor and sensory areas (for the olfactory area,
see Fig. 18). The visual area proper, or "visuo-sensory area," lies
just around the corner from the spot marked "Visual," on the middle
surface of the hemisphere, where it adjoins the other hemisphere.
(Figure text: frontal lobe, parietal lobe, central fissure, occipital
lobe, motor area, somesthetic area, auditory area, fissure of Sylvius,
temporal lobe, brain stem, cerebellum)]


The _lower_ motor centers, called also reflex centers, are located in
the cord or brain stem, and their nerve cells give rise to the axons
that form the motor nerves and connect with the muscles and glands. A
muscle is thrown into action by nerve currents from its lower motor
center.

The principal _higher_ motor center is the "motor area" of the brain,
located in the cortex or external layer of gray matter, in the
cerebrum. More precisely, the motor area is a long, narrow strip of
cortex, lying just forward of what is called the "central fissure" or
"fissure of Rolando".

{51}

If you run your finger over the top of the head from one side to the
other, about halfway back from the forehead, the motor areas of the
two cerebral hemispheres will lie close under the path traced by your
finger.


[Illustration: Fig. 13.--(After Cajal.) Type of the brain cells that
most directly control muscular movement. (Figure text: Axon. Giant
pyramid cell from the motor area of the cerebral cortex, magnified 35
diameters. Cell body of same farther magnified)]


The motor area in the right hemisphere is connected with the left half
of the cord and so with the muscles of the left half of the body; the
motor area of the left hemisphere similarly affects {52} the right
half of the body. Within the motor area are centers for the several
limbs and other motor organs. Thus, at the top, near the middle line
of the head (and just about where the phrenologists located their
"bump of veneration"!), is the center for the legs; next below and to
the side is the center for the trunk, next that for the arm, next that
for head movements, and at the bottom, not far from the ears, is the
center for tongue and mouth.


[Illustration: Fig. 14.--The nerve path by which the motor area of the
cortex influences the muscles. The upper part of this path, consisting
of axons issuing from the giant pyramids of the motor area and
extending down into the spinal cord, is the pyramidal tract. The lower
part of the path consists of axons issuing from the motor cells of the
cord and extending out to the muscles. The top of the figure
represents a vertical cross-section of the brain, such as is given, on
a larger scale, in Fig. 18. (Figure text: cortex, cord, muscles)]


The largest nerve cells of all are found in the motor area, and are
called, from their shape, the "giant pyramids". They have large
dendrites and very long axons, which latter, {53} running in a thick
bundle down from the cortex through the brain stem and cord,
constitute the "pyramidal tract", the principal path of communication
from the cerebrum to the lower centers. The motor area of the brain
has no direct connection with any muscle, but acts through the
pyramidal tract on the lower centers, which in turn act on the
muscles.


How The Brain Produces Muscular Movements

The motor area is itself aroused to action by nerve currents entering
it through axons coming from other parts of the cortex; and it is by
way of the motor area that any other part of the cortex produces
bodily movement. There are a few exceptions, as, for example, the
movements of the eyes are produced generally by the "visual area"
acting directly on the lower motor centers for the eye in the brain
stem; but, in the main, any motor effect of brain action is exerted
through the motor area. The motor area, as already mentioned, acts on
the lower motor centers in the cord and brain stem, and these in turn
on the muscles; but we must look into this matter a little more
closely.

A lower motor center is a group of motor and central neurones, lying
anywhere in the cord or brain stem, and capable of directly arousing a
certain cooerdinated muscular movement. One such unit gives flexion of
the leg, another gives extension of the leg, a third gives the rapid
alternation of flexion and extension that we see in the scratching
movement of the dog. Such a motor center can be aroused to activity by
a sensory stimulus, and the resulting movement is then called a
reflex.

The lower center can be aroused in quite another way, and that is by
nerve currents coming from the brain, by way of the motor area and the
pyramidal tract. Thus flexion of the leg can occur voluntarily as well
as reflexly. The same {54} muscles, and the same motor neurones, do
the job in either case. In the reflex, the lower center is aroused by
a sensory nerve, and in the voluntary movement by the pyramidal tract.

The story is told of a stranger who was once dangling his legs over
the edge of the station platform at a small backwoods town, when a
native called out to him "Hist!" (hoist), pointing to the ground under
the stranger's feet. He "histed" obediently, which is to say that he
voluntarily threw into play the spinal center for leg flexion; and
then, looking down, saw a rattler coiled just beneath where his feet
had been hanging. Now even if he had spied the rattler first, the
resulting flexion, though impulsive and involuntary, would still have
been aroused by way of the motor area and the pyramidal tract, since
the movement would have been a response to _knowledge_ of what that
object was and signified, and knowledge means action by the cerebral
cortex, which we have seen to affect movement through the medium of
the motor area. But if the snake had made the first move, the same leg
movement on the man's part, made now in response to the painful
sensory stimulus, would have been the flexion reflex.


Facilitation and Inhibition

Not only can the motor area call out essentially the same movements
that are also produced reflexly, but it can prevent or _inhibit_ the
execution of a reflex in spite of the sensory stimulus for the reflex
being present, and it can reinforce or _facilitate_ the action of the
sensory stimulus so as to assist in the production of the reflex. We
see excellent examples of cerebral facilitation and inhibition in the
case of the knee jerk. This sharp forward kick of the foot and lower
leg is aroused by a tap on the tendon running in front {55} of the
knee. Cross the knee to be stimulated over the other leg, and tap the
tendon just below the knee cap, and the knee jerk appears. So purely
reflex is this movement that it cannot be duplicated voluntarily; for,
though the foot can of course be voluntarily kicked forward, this
voluntary movement does not have the suddenness and quickness of the
true reflex. For all that, the cerebrum can exert an influence on the
knee jerk. Anxious attention to the knee jerk inhibits it; gritting
the teeth or clenching the fist reinforces it. These are cerebral
influences acting by way of the pyramidal tract upon the spinal center
for the reflex.

Thus the cortex controls the reflexes. Other examples of such control
are seen when you prevent for a time the natural regular winking of
the eyes by voluntarily holding them wide open, or when, carrying a
hot dish which you know you must not drop, you check the flexion
reflex which would naturally pull the hand away from the painful
stimulus. The young child learns to control the reflexes of
evacuation, and gradually comes to have control over the breathing
movements, so as to hold his breath or breathe rapidly or deeply at
will, and to expire vigorously in order to blow out a match.

The coughing, sneezing and swallowing reflexes likewise come under
voluntary control. In all such cases, the motor area facilitates or
inhibits the action of the lower centers.


Super-motor Centers in the Cortex

Another important effect of the motor area upon the lower centers
consists in combining their action so as to produce what we know as
skilled movements. It will be remembered that the lower centers
themselves give cooerdinated movements, such as flexion or extension of
the whole limb; but still higher cooerdinations result from cerebral
control. {56} When the two hands, though executing different
movements, work together to produce a definite result, we have
cooerdination controlled by the cortex. Examples of this are seen in
handling an ax or bat, or in playing the piano or violin. A movement
of a single hand, as in writing or buttoning a coat, may also
represent a higher or cortical cooerdination.


[Illustration: Fig. 15.--(From Starr.) Axons connecting one part of
the cortex with another. The brain is seen from the side, as if in
section. At "A" are shown bundles of comparatively short axons,
connecting near-by portions of the cortex; while "B," "C," and "D"
show bundles of longer axons, connecting distant parts of the cortex
with one another. The "Corpus Callosum" is a great mass of axons
extending across from each cerebral hemisphere to the other, and
enabling both hemispheres to work together. "O. T." and "C. N." are
interior masses of gray matter, which can be seen also in Fig. 18. "O.
T." is the thalamus, about which more later.]


Now it appears that the essential work in producing these higher
cooerdinations of skilled movement is performed not by the motor area,
but by neighboring parts of the cortex, which act on the motor area in
much the same way as the motor area acts on the lower centers. Some of
these {57} skilled-movement centers, or super-motor centers, are
located in the cortex just forward of the motor area, in the adjacent
parts of the frontal lobe. Destruction of the cortex there, through
injury or disease, deprives the individual of some of his skilled
movements, though not really paralyzing him. He can still make simple
movements, but not the complex movements of writing or handling an
instrument.

It is a curious fact that the left hemisphere, which exerts control
over the movements of the right hand and right side of the body
generally, also plays the leading part in skilled movements of either
hand. This is true, at least, of right-handed persons; probably in the
left-handed the right hemisphere dominates.

Motor power may be lost through injury at various points in the
nervous system. Injury to the spinal cord, destroying the lower motor
center for the legs, brings complete paralysis. Injury to the motor
area or to the pyramidal tract does not destroy reflex movement, but
cuts off all voluntary movement and cerebral control. Injury to the
"super-motor centers" causes loss of skilled movement, and produces the
condition of  "apraxia", in which the subject, though knowing what he
wants to do, and though still able to move his limbs, simply cannot
get the combination for the skilled act that he has in mind.


Speech Centers

Similar to apraxia is "aphasia" or loss of ability to speak. It bears
the same relation to true paralysis of the speech organs that hand
apraxia bears to paralysis of the hand. Through brain injury it
sometimes happens that a person loses his ability to speak words,
though he can still make vocal sounds. The cases differ in severity,
some retaining the ability to speak only one or two words which {58}
from frequent use have become almost reflex (swear words, sometimes,
or "yes" and "no"), while others are able to pronounce single words,
but can no longer put them together fluently into the customary form
of phrases and sentences, and still others can utter simple sentences,
but not any connected speech.


[Illustration: Fig. 16.--Side view of the left hemisphere, showing the
location of the "speech centers." The region marked "Motor" is the
motor speech center, that marked "Auditory" the auditory speech
center, and that marked "Visual" the visual speech center. (Figure text:
central fissure, motor area, auditory area, visual area, fissure of
Sylvius, brain stem, cerebellum)]


In pure cases of _motor aphasia_, the subject knows the words he
wishes to say, but cannot get them out. The brain injury here lies in
the frontal lobe in the left hemisphere, in right-handed people, just
forward of the motor area for the mouth, tongue and larynx. This
"motor speech center" is the best-known instance of a super-motor
center. It cooerdinates the elementary speech movements into the
combinations called words; and perhaps there is no other motor
performance so highly skilled as this of speaking. It is acquired so
early in life, and practised so constantly, that {59} we take it quite
as a matter of course, and think of a word as a simple and single
movement, while in fact even a short word, as spoken, is a complex
movement requiring great motor skill.

There is some evidence that the motor speech center extends well
forward into the frontal lobe, and that the front part of it is
related to the part further back as this is to the motor area back of
it. That is to say, the back of the speech center combines the motor
units of the motor area into the skilled movements of speaking a word,
while the more forward part of the speech center combines the word
movements into the still more complex movement of speaking a sentence.
It is even possible that the very front part of the speech center has
to do with those still higher combinations of speech movements that
give fluency and real excellence of speaking.


The Auditory Centers

Besides the motor aphasia, just mentioned, there is another type,
called _sensory aphasia_, or, more precisely, auditory aphasia. In
pure auditory aphasia there is no inability to pronounce words or even
to speak fluently, but there is, first, an inability to "hear words",
sometimes called word deafness, and there is often also an inability
to find the right words to speak, so that the individual so afflicted,
while speaking fluently enough and having sense in mind, misuses his
words and utters a perfect jargon. One old gentleman mystified his
friends one morning by declaring that he must go and "have his
umbrella washed", till it was finally discovered that what he wanted
was to have his hair cut.

The cortical area affected in this form of aphasia is located a little
further back on the surface of the brain than {60} the motor speech
center, being close to the auditory area proper. The latter is a small
cortical region in the temporal lobe, connected (through lower
centers) with the ear, and is the only part of the cortex to receive
nerve currents from the organ of hearing. The auditory area is,
indeed, the organ of hearing, or an organ of hearing, for without it
the individual is deaf. He may make a few reflex responses to loud
noises, but, consciously, he does not hear at all; he has no auditory
sensations.

In the immediate neighborhood of the auditory area proper (or of the
"auditory-sensory area", as it may well be called), are portions of
the cortex intimately connected by axons with it, and concerned in
what may be called auditory perceptions, i.e., with recognizing and
understanding sounds. Probably different portions of the cortex near
the auditory-sensory center have to do with different sorts of
auditory perception. At least, we sometimes find individuals who, as a
result of injury or disease affecting this general region, are unable
any longer to follow and appreciate music. They cannot "catch the
tune" any longer, though they may have been fine musicians before this
portion of their cortex was destroyed. In other cases, we find,
instead of this music deafness, the word deafness mentioned just
above.

The jargon talk that so often accompanies word deafness reminds us of
the fact that speech is first of all auditory to the child. He
understands what is said to him before he talks himself, and his
vocabulary for purposes of understanding always remains ahead of his
speaking vocabulary. It appears that this precedence of auditory
speech over motor remains the fact throughout life, in most persons,
and that the auditory speech center is the most fundamental of all the
speech centers, of which there is one more not yet mentioned, used in
reading.

{61}

[Illustration: Fig. 17.--(From Cajal.) Magnified sections through the
cortex, to show the complexity of its inner structure. One view shows
nerve cells and their dendrites, with only a few axons, while the
other shows axons, outgoing and incoming, and some of their fine
branches. Imagine one view superimposed upon the other, and you get
some idea of the intricate interweaving of axons and dendrites that
occurs in the cortex.]

{62}

The Visual Centers

There is a visual-sensory area in the occipital lobe, at the back of
the brain, that is connected with the eye in the same way as the
auditory center is connected with the ear. Without it, the individual
still shows the pupillary reflex to light, but has no sensations of
sight. He is blind.


[Illustration: Fig. 18.--Vertical cross-section through the brain,
showing the cortex on the outside, the thalamus and other interior
masses of gray matter, some of the paths to and from the cortex, and
the callosum or bridge of axons connecting the two cerebral
hemispheres. The "Motor path" is the pyramidal tract, only the
beginning of which is shown here, its further course being indicated
in Fig. 14. (Figure text:  tactile path, motor path, auditory path,
callosum, thalamus, olfactory area)]


This visual-sensory area occupies only a small portion of the
occipital lobe, and yet practically the whole lobe is concerned with
vision. Some portions of the lobe are concerned in perceiving words in
reading, and without them the individual is "word blind". Other
portions are concerned in perceiving (recognizing, understanding) seen
objects, and without them the individual is "object blind". Other {63}
portions are concerned in perceiving color relations, and still other
portions in perceiving spatial relations through the sense of sight
and so knowing where seen objects are and being able to guide one's
movements by sight.


Cortical Centers for the Other Senses

There is an olfactory area in a rather secluded part of the cortex,
and this is related to the sense of smell in the same general way.
Probably there is a similar taste center, but it has not been
definitely located. Then there is a large and important area called
the "somesthetic", connected with the body senses generally, i.e.,
chiefly with the skin and muscle senses. This area is located in a
narrow strip just back of the central fissure, extending parallel to
the motor area which lies just in front of the fissure, and
corresponding part for part with it, so that the sensory area for the
legs lies just behind the motor area for the legs, and so on.
Destruction of any part of this somesthetic area brings loss of the
sensations from the corresponding part of the body.

Just behind this direct sensory center for the body, in the parietal
lobe, are portions of the cortex concerned in perceiving facts by aid
of the body senses. Perception of size and shape by the sense of
touch, perception of weight by the muscle sense, perception of degrees
of warmth and cold by the temperature sense, are dependent on the
parietal lobe and disappear when the cortex of this region is
destroyed. It appears that there is a sort of hierarchy of centers
here, as in the motor region and probably also in the visual and
auditory regions. Skill in handling objects is partly dependent on the
"feel" of the objects and so is impaired by injuries to the parietal
lobe, as well as by injury to the frontal lobe; and knowing how to
manage a fairly complex situation, as in lighting a fire when you have
the various {64} materials assembled before you, seems also to depend
largely on this part of the cortex.


Lower Sensory Centers


[Illustration: Fig. 19.--Sensory path from the skin of any portion of
the trunk or limbs. The path consists of three neurones, the cell body
of the first lying just outside the spinal cord, that of the second
lying in the cord, and that of the third lying in the thalamus. The
last part of this path is the "Tactile path," shown in Fig. 18.
(Figure text:  cortex, thalamus, cord, skin)]


As already indicated, no portion of the cortex, not even the sensory
areas, is directly connected with any sense organ. The sensory axons
from the skin, for example, terminate in the spinal cord, in what may
be called the lowest sensory centers. Here are nerve cells whose axons
pass up through the cord and brain stem to the thalamus or interbrain,
where they terminate in a second sensory center. And cells here send
their axons up to the somesthetic area of the cortex.

{65}

The thalamus is remarkable as an intermediate center for all the
senses, except smell; but exactly what is accomplished by this big
intermediate sensory center remains rather a mystery, though it
certainly appears that the thalamus has something to do with feeling
and emotion.


The Cerebellum

Regarding the cerebellum, there is much knowledge at hand, but it is
difficult to give the gist of it in a few words. On the one hand, the
cerebellum receives a vast number of axons from the lower sensory
centers; while, on the other hand, it certainly has nothing to do with
conscious sensation or perception. Its use seems to be motor. It has
much to do with maintaining the equilibrium of the body, and probably
also with maintaining the steadiness and general efficiency of
muscular contraction. Though it has no known sensory or intellectual
functions, it is very closely connected with the cerebrum, receiving a
tremendous bundle of axons from different parts of the cerebrum, by
way of the brain stem. Possibly these are related to motor activity.
The phrenologists taught that the cerebellum was the center for the
sexual instinct, but there is no evidence in favor of this guess.


Different Levels of Reaction

Let a noise strike the ear and start nerve currents in along the
auditory nerve, passing through the lowest and intermediate centers
and reaching the auditory-sensory area of the cortex. When this last
is aroused to activity, we have a sensation of sound, which is the
first conscious reaction to the external stimulus. Axons running from
the auditory-sensory to the near-by cortex give a perception of some
fact indicated by the external stimulus, and this perception is a {66}
second and higher conscious reaction, which, to be sure, ordinarily
occurs so quickly after the first that introspection cannot
distinguish one as first and the other as second; but the facts of
brain injury, already mentioned, enable us to draw the distinction.
The perceived fact may call up a mental image, or a recognition of
some further fact less directly signified by the noise; these would be
reactions of still higher order. Much of the cortex is apparently not
very directly connected with either the sensory or the motor areas,
and probably is concerned somehow in the recognition of facts that are
only very indirectly indicated by any single sensory stimulus, or with
the planning of actions that only indirectly issue in muscular
movement.

On the sensory and intellectual side, the higher reactions follow the
lower: sensation arouses perception and perception thought. On the
motor side, the lower reactions are aroused by the higher. Thus the
speech center arouses the motor centers for the speech organs,
combining the action of these into the speaking of a word; and in a
similar way, it seems, the intention to speak a sentence expressing a
certain meaning acts as a stimulus to call up in order the separate
words that make the sentence. A general plan of action precedes and
arouses the particular acts and muscular movements that execute the
plan.

{67}

EXERCISES

1. Outline of the chapter. Fill in sub-topics under each of the
   following heads:

   A. Mental processes of all kinds are reactions.

   B. The stimulus that directly arouses a mental process is often
      "central".

   C. Brain activities of all sorts influence the muscles by way
      of the motor area and the lower motor centers.

   D. Brain action in skilled movement.

   E. Brain action in speech.

   F. Brain action in sensation.

   G. Brain action in recognizing seen or heard objects.

   H. Relations of reactions of different levels.

2. Define and illustrate these classes of stimuli:

   A. Peripheral:

      (1) External.

      (2) Internal.

   B. Central.

3. Show by a diagram how one cortical center arouses another.
   Compare the diagram in Fig. 9, p. 37.

4. Facilitation of the patellar reflex or "knee jerk". Let your
   subject sit with one leg hanging freely from the knee down. With
   the edge of your hand strike the patellar tendon just below the
   knee cap. (a) Compare the reflex movement so obtained with a
   voluntary imitation by the subject. Which is the quicker and
   briefer? (b) Apply a fairly strong auditory stimulus (a sudden
   noise) a fraction of a second before the tap on the tendon, and see
   whether the reflex response is reinforced, (c) Ask the subject to
   clench his fists or grit his teeth, and tap the tendon as he does
   so. Reinforcement? (d) Where is the reflex center for the patellar
   reflex, and whence comes the reinforcing influence?

5. Construct a diagram showing the different centers and connections
   involved in making the skilled movement of writing; and consider
   what loss of function would result from destruction of each of the
   centers.


REFERENCES

Herrick's _Introduction to Neurology_, 1918, Chapter XX, on the
"Functions of the Cerebrum".

Stile's _Nervous System and Its Conservation_, Chapters X, XI
and XII.


{68}


CHAPTER IV

TENDENCIES TO REACTION

HOW MOTIVES INFLUENCE BEHAVIOR, AND HOW THEY FIT INTO A PSYCHOLOGY
WHICH SEEKS TO ANALYZE BEHAVIOR INTO REACTIONS.

One advantage of basing our psychology on _reactions_ is that it keeps
us "close to the ground", and prevents our discussions from sailing
off into the clouds of picturesque but fanciful interpretation.
Psychology is very apt to degenerate into a game of blowing bubbles,
unless we pin ourselves down to hard-headed ways of thinking. The
notion of a reaction is of great value here, just because it is so
hard-headed and concrete. Whenever we have any human action before us
for explanation, we have to ask what the stimulus is that arouses the
individual to activity, and how he responds. Stimulus-response
psychology is solid, and practical as well; for if it can establish
the laws of reaction, so as to predict what response will be made to a
given stimulus, and what stimulus can be depended on to arouse a
desired response, it furnishes the "knowledge that is power". Perhaps
no more suitable motto could be inscribed over the door of a
psychological laboratory than these two words, "Stimulus-Response."

Such a motto would not frighten away the modern introspectionists, for
they, no less than the behaviorists, could find a congenial home in a
stimulus-response laboratory. They would begin by studying sensations,
and, advancing to more complex responses, would observe the conscious
processes entering into the response.

{69}

But, however useful the reaction may be as affording a sound basis for
psychological study, we must not allow it to blind our eyes to any of
the real facts of mental life; and, at first thought, it seems as if
_motives, interests_ and _purposes_ did not fit into the
stimulus-response program. Many hard-headed psychologists have fought
shy of such matters, and some have flatly denied them any place in
scientific psychology. But let us see.


  _S ---> R_

[Illustration: Fig. 20.--The symbol of stimulus-response psychology.
_S_ means the stimulus, and _R_ the response. The line between is the
connection from stimulus to response.]


Suppose we are looking out on a city street during the noon hour. We
see numbers of people who--lunch over, nothing to do till one
o'clock!--are standing or walking about, looking at anything that
chances to catch their eye, waving their hands to friends across the
street, whistling to a stray dog that comes past, or congregating
about an automobile that has broken down in the crowded thoroughfare.
These people are responding to stimuli, obviously enough, and there is
no difficulty in fitting their behavior into the stimulus-response
scheme.

But here comes some one who pays little attention to the sights and
sounds of the street, simply keeping his eyes open enough to avoid
colliding with any one else. He seems in a hurry, and we say of him,
"He must have business on hand; he has to keep an appointment or catch
a train". He is not simply responding to the stimuli that come to him,
but has some purpose of his own that directs his movements.

Here is another who, while not in such a hurry, is not idling by any
means, since he peers closely at the faces of the men, neglecting the
women, and seems to be looking for some one in particular; or,
perhaps, he neglects men and {70} women alike, and looks anxiously at
the ground, as if he had lost something. Some inner motive shuts him
off from most of the stimuli of the street, while making him extra
responsive to certain sorts of stimuli.


Purposive Behavior

Now it would be a great mistake to rule these purposeful individuals
out of our psychology. We wish to understand busy people as well as
idlers. What makes a man busy is some inner purpose or motive. He
still responds to present stimuli--otherwise he would be in a dream or
trance and out of all touch with what was going on about him--but his
actions are in part controlled by an inner motive.

To complete the foundations of our psychology, then, we need to fit
purpose into the general plan of stimulus and response. At first
thought, purpose seems a misfit here, since--

First, a purpose is an inner force, whereas what arouses a response
should be a stimulus, and typically an external stimulus. We do not
wish to drop back into the old "self-activity" psychology, which
thought of the individual as originating his acts from within himself.
But if we could show that a purpose is itself an inner response to
some external stimulus, and acts in its turn as a "central stimulus"
to further reactions, this difficulty would disappear.

Second, while a typical reaction, like the reflex or the simple
reaction of the experiment, is prompt and over with at once, a purpose
persists. It keeps the busy man, in our illustration, hurrying all the
way down the street and around the corner and how much farther we
cannot say. It is very different from a momentary response, or from a
stimulus that arouses a momentary response and nothing more.

Third, what persists, in purposive behavior, is the tendency {71}
towards some end or goal. The purposeful person wants something he has
not yet got, and is striving towards some future result. Whereas a
stimulus pushes him from behind, a goal beckons to him from ahead.
This element of action directed towards some end is absent from the
simple response to a stimulus.

In short, we have to find room in our stimulus-response psychology for
action persistently steered in a certain direction by some cause
acting from within the individual. We must find room for _internal_
states that _last_ for a time and _direct_ action. In addition, we
sometimes, though not always, need to find room for conscious
foreknowledge of the goal towards which the action is directed.


[Illustration: Fig. 21.--The stimulus-response scheme complicated to
allow for the existence of T, an inner motive or tendency, which,
aroused by an external stimulus, itself arouses a motor response. If
the reaction-tendency were linked so firmly to a single response as to
arouse that response with infallible certainty and promptness, then it
would be superfluous for psychology to speak of a tendency at all. But
often quite a series of responses, R1, R2, etc., follows upon a single
stimulus, all tending towards the same end-result, such as escape; and
then the notion of a "tendency" is by no means superfluous.]


"Purpose" is not the best general term to cover all the internal
factors that direct activity, since this word rather implies foresight
of the goal, which demands the intellectual ability to imagine a
result not present to the senses. This highest level of inner control
over one's behavior had best be left for consideration in later
chapters on imagination and will. There are two levels below this. In
the middle level, the individual has an inner steer towards a certain
result, though without conscious foresight of that result. At the
lowest level, we can scarcely speak of the individual as being
directed towards any precise goal, but still his {72} internal state
is such as to predispose him for certain reactions and against other
reactions.

The lowest level, that of organic states, is typified by fatigue. The
middle level, that of internal steer, is typified by the hunting dog,
striving towards his prey, though not, as far as we know, having any
clear idea of the result at which his actions are aimed. The highest
level, that of conscious purpose, is represented by any one who knows
exactly what he wants and means to get.

No single word in the language stands out clearly as the proper term
to cover all three levels. "Motives" would serve, if we agree at the
outset that a motive is not always clearly conscious or definite, but
may be any inner state or force that drives the individual in a given
direction. "Wants" or "needs" might be substituted for "motives", and
would apply better than "motives" to the lowest of our three levels.
"Tendencies", or "tendencies to reaction", carries about the right
meaning, namely that the individual, because of his internal state,
tends towards a certain action. "Determining tendencies" (perhaps
better, "directive tendencies") is a term that has been much used in
psychology, with the meaning that the inner tendency determines or
directs behavior. Much used also are "adjustment" and "mental set",
the idea here being to liken the individual to an adjustable machine
which can be set for one or another sort of work. Often "preparation"
or "readiness for action" is the best expression.


Organic States that Influence Behavior

Beginning at the lowest of our three levels, let us observe not even
the simplest animal, but a single muscle. If we give a muscle electric
shocks as stimuli, it responds to each shock by contracting. To a weak
stimulus, the response is weak; {73} to a strong stimulus, strong. But
now let us apply a long series of equal shocks of moderate intensity,
one shock every two seconds. Then we shall get from the muscle what is
called a "fatigue curve", the response growing weaker and weaker, in
spite of the continued equality of the stimuli. How is such a thing
possible? Evidently because the inner condition of the muscle has been
altered by its long-continued activity. The muscle has become
fatigued, and physiologists, examining into the nature of this
fatigue, have found the muscle to be poisoned by "fatigue substances"
produced by its own activity. Muscular contraction depends on the
oxidation of fuel, and produces oxidized wastes, of which carbon
dioxide is the best known; and these waste products, being produced in
continued strong activity faster than the blood can carry them away,
accumulate in the muscle and partially poison it. The "organic state"
is here definitely chemical.


[Illustration: Fig. 22.--Fatigue curve of a muscle. The vertical lines
record a series of successive contractions of the muscle, and the
height of each line indicates the force of the contraction. Read from
left to right.]


This simple experiment is worth thinking over. Each muscular
contraction is a response to an electric stimulus, but the force of
the contraction is determined in part by the internal state of the
muscle. Fatigue is an _inner_ state of the muscle that _persists_ for
a time (till the blood carries away the wastes), and that
_predisposes_ the muscle _towards_ a certain kind of response, namely,
weak response. Thus the three characteristics of purposive behavior
that seemed so {74} difficult to fit into the scheme of stimulus and
response are all here in a rudimentary form.

But notice this fact also: the inner condition of _muscular fatigue is
itself a response_ to external stimuli. It is part and parcel of the
total muscular response to a stimulus. The total response includes an
internal change of condition, which, persisting for a time, is a
factor in determining how the muscle shall respond to later stimuli.
These facts afford, in a simple form, the solution of our problem.

Before leaving the muscle, let us take note of one further fact. If
you examine the "fatigue curve" closely, you will see that a perfectly
fresh muscle _gains_ in strength from its first few responses. It is
said to "warm up" through exercise; and the inner nature of this
warming up has been found to consist in a moderate accumulation of the
same products which, in greater accumulation, produce fatigue. The
warmed-up condition is then another instance of an "organic state".

There will be more to say of "organic states" when we come to the
emotions. For the present, do not the facts already cited compel us to
enlarge somewhat the conception of a reaction as we left it in the
preceding chapters? Besides the external response, there is often an
internal response to a stimulus, a changed organic state that persists
for a time and has an influence on behavior. The motor response to a
given stimulus is determined partly by that stimulus, and partly by
the organic state left behind by just preceding stimuli. You cannot
predict what response will be made to a given stimulus, unless you
know the organic state present when the stimulus arrives.


Preparation for Action

At the second level, the inner state that partly governs the response
is more neural than chemical, and is directed {75} specifically
towards a certain end-result. As good an instance as any is afforded
by the "simple reaction", described in an earlier chapter. If the
subject in that experiment is to raise his finger promptly from the
telegraph key on hearing a given sound, he must be _prepared_, for there
is no permanent reflex connection between this particular stimulus and
this particular response. You tell your subject to be ready, whereupon
he places his finger on the key, and gets all ready for this
particular stimulus and response. The response is determined as much
by his inner state of readiness as by the stimulus. Indeed, he
sometimes gets too ready, and makes the response before he receives
the stimulus.

The preparation in such a case is more specific, less a general
organic state, than in the previous cases of fatigue, etc. It is
confined for the most part to the nervous system and the sense organ
and muscles that are to be used. In an untrained subject, it includes
a conscious purpose to make the finger movement quickly when the sound
is heard; but as he becomes used to the experiment he loses clear
consciousness of what he is to do. He is, as a matter of fact, ready
for a specific reaction, but all he is conscious of is a general
readiness. He feels ready for what is coming, but does not have to
keep his mind on it, since the specific neural adjustment has become
automatic with continued use.

Examples of internal states of preparedness might be multiplied
indefinitely, and it may be worth while to consider a few more, and
try out on them the formula that has already been suggested, to the
effect that preparation is an inner adjustment for a specific
reaction, set up in response to some stimulus (like the "Ready!"
signal), persisting for a time, and predisposing the individual to
make the specified reaction whenever a suitable stimulus for it
arrives. The preparation may or may not be conscious. It might be
named "orientation" or "steer", with the meaning that {76} the
individual is headed or directed towards a certain end-result. It is
like so setting the rudder of a sailboat that, when a puff of wind
arrives, the boat will respond by turning to the one side.

The runner on the mark, "set" for a quick start, is a perfect picture
of preparedness. Here the onlookers can see the preparation, since the
ready signal has aroused visible muscular response in the shape of a
crouching position. It is not simple crouching, but "crouching to
spring." But if the onlookers imagine themselves to be seeing the
whole preparation--if they suppose the preparation to be simply an
affair of the muscles--they overlook the established fact that the
muscles are held in action by the nerve centers, and would relax
instantly if the nerve centers should stop acting. The preparation is
neural more than muscular. The neural apparatus is set to respond to
the pistol shot by strong discharge into the leg muscles.

What the animal psychologists have called the _delayed reaction_ is a
very instructive example of preparation. An animal is placed before a
row of three food boxes, all looking just alike, two of them, however,
being locked while the third is unlocked. Sometimes one is unlocked
and sometimes another, and the one which at any time is unlocked is
designated by an electric bulb lighted above the door. The animal is
first trained to go to whichever box shows the light; he always gets
food from the lighted box. When he has thoroughly learned to respond
in this way, the "delayed reaction" experiment begins. Now the animal
is held while the light is burning, and only released a certain time
after the light is out, and the question is whether, after this delay,
he will still follow the signal and go straight to the right door. It
is found that he will do so, provided the delay is not too long--how
long depends on the animal. With rats the delay cannot exceed 5
seconds, with cats it can reach 18 {77} seconds, with dogs 1 to 3
minutes, with children (in a similar test) it increased from 20
seconds at the age of fifteen months to 50 seconds at two and a half
years, and to 20 minutes or more at the age of five years.

Rats and cats, in this experiment, need to keep their heads or bodies
turned towards the designated box during the interval between the
signal and the release; or else lose their orientation. Some dogs,
however, and children generally, can shift their position and still,
through some inner orientation, react correctly when released. The
point of the experiment is that the light signal puts the animal or
child into a state tending towards a certain result, and that, when
that result is not immediately attainable, the state persists for a
time and produces results a little later.


Preparatory Reactions

In the delayed reaction, the inner orientation does little during the
interval before the final reaction, except to maintain a readiness for
making that reaction; but often "preparatory reactions" occur before
the final reaction can take place. Suppose you whistle for your dog
when he is some distance off and out of sight. You give one loud
whistle and wait. Presently the dog swings around the corner and
dashes up to you. Now, what kept the dog running towards you after
your whistle had ceased and before he caught sight of you? Evidently
he was directed towards the end-result of reaching you, and this
directing tendency governed his movements during the process. He made
many preparatory reactions on the way to his final reaction of jumping
up on you; and these preparatory reactions were, of course, responses
to the particular trees he had to dodge, and the ditches he had to
jump; but they were at the same time governed by the inner state set
up in him by your {78 } whistle. This inner state favored certain
reactions and excluded others that would have occurred if the dog had
not been in a hurry. He passed another dog on the way without so much
as saying, "How d'ye do?" And he responded to a fence by leaping over
it, instead of trotting around through the gate. That is to say, the
inner state set up in him by your whistle _facilitated_ reactions that
were preparatory to the final reaction, and _inhibited_ reactions that
were not in that line.

A hunting dog following the trail furnishes another good example of a
directive tendency. Give a bloodhound the scent of a particular man
and he will follow that scent persistently, not turning aside to
respond to stimuli that would otherwise influence him, nor even to
follow the scent of another man. Evidently an inner neural adjustment
has been set up in him predisposing him to respond to a certain
stimulus and not to others.

The homing of the carrier pigeon is a good instance of activity
directed in part by an inner adjustment, since, when released at a
distance from home, he is evidently "set" to get back home, and often
persists and reaches home after a very long flight. Or, take the
parallel case of the terns, birds which nest on a little island not
far from Key West. Of ten birds taken from their nests and transported
on shipboard out into the middle of the Gulf of Mexico and released
500 miles from home, eight reappeared at their nests after intervals
varying from four to eight days. How they found their way over the
open sea remains a mystery, but one thing is clear: they persisted in
a certain line of activity until a certain end-result was reached, on
which this line of activity ceased.

One characteristic of tendencies that has not previously been
mentioned comes out in this example. When a tendency has been aroused,
the animal (or man) is tense and {79} restless till the goal has been
reached, and then quiets down. The animal may or may not be clearly
conscious of the goal, but he is restless till the goal has been
attained, and his restlessness then ceases. In terms of behavior, what
we see is a series of actions which continues till a certain result
has been reached and then gives way to rest. Introspectively, what we
feel (apart from any clear mental picture of the goal) is a
restlessness and tenseness during a series of acts, giving way to
relief and satisfaction when a certain result has been reached.

A hungry or thirsty animal is restless; he _seeks_ food or drink,
which means that he is making a series of preparatory reactions, which
continues till food or drink has been found, and terminates in the
end-reaction of eating or drinking.


What the Preparatory Reactions Accomplish

The behavior of a hungry or thirsty individual is worth some further
attention--for it is the business of psychology to interest itself in
the most commonplace happenings, to wonder about things that usually
pass for matters of course, and, if not to find "sermons in stones",
to derive high instruction from very lowly forms of animal behavior.
Now, what is hunger? Fundamentally an organic state; next, a sensation
produced by this organic state acting on the internal sensory nerves,
and through them arousing in the nerve centers an adjustment or
tendency towards a certain end-reaction, namely, eating. Now, I ask
you, if hunger is a stimulus to the eating movements, why does not the
hungry individual eat at once? Why, at least, does he not go through
the motions of eating? You say, because he has nothing to eat. But he
could still make the movements; there is no physical impossibility in
his making chewing and swallowing movements without the presence of
food. {80} Speaking rationally, you perhaps say that he does not make
these movements because he sees they would be of no use without food
to chew; but this explanation would scarcely apply to the lower sorts
of animal, and besides, you do not have to check your jaws by any such
rational considerations. They simply do not start to chew except when
food is in the mouth. Well, then, you say, chewing is a response to
the presence of food in the mouth; and taking food into the mouth is a
response to the stimulus of actually present food. The response does
not occur unless the stimulus is present; that is simple.

Not quite so simple, either. Unless one is hungry, the presence of
food does not arouse the feeding reaction; and even food actually
present in the mouth will be spewed out instead of chewed and
swallowed, if one is already satiated. Try to get a baby to take more
from his bottle than he wants! Eating only occurs when one is _both_
hungry and in the presence of food. Two conditions must be met: the
internal state of hunger and the external stimulus of food; then, and
then only, will the eating reaction take place.

Hunger, though a tendency to eat, does not arouse the eating movements
while the stimulus of present food is lacking; but, for all that,
hunger does arouse immediate action. It typically arouses the
preparatory reactions of seeking food. Any such reaction is at the
same time a response to some actually present stimulus. Just as the
dog coming at your whistle was responding every instant of his
progress to some particular object--leaping fences, dodging trees--so
the dog aroused to action by the pangs of hunger begins at once to
respond to present objects. He does not start to eat them, because
they are not the sort of stimuli that produce this response, but he
responds by dodging them or finding his way by them in his quest for
food. The responses that the hungry dog makes to other objects than
{81} food are preparatory reactions, and these, if successful, put the
dog in the presence of food. That is to say, the _preparatory
reactions provide the stimulus that is necessary to arouse the
end-reaction_. They bring the individual to the stimulus, or the
stimulus to the individual.


[Illustration: Fig. 23.--A stimulus arouses the tendency towards the
end-reaction, R, but (as indicated by the dotted line), T is not by
itself sufficient to arouse R; but T can and does arouse P, a
preparatory reaction, and P (or some external result directly produced
by P), cooeperating with T, gives rise to R.]


What we can say about the modus operandi of hunger, then, amounts to
this: Hunger is an inner state and adjustment predisposing the
individual to make eating movements in response to the stimulus of
present food; in the absence of food, hunger predisposes to such other
responses to various stimuli as will bring the food stimulus into
play, and thus complete the conditions necessary for the eating
reaction. In general, _an aroused reaction-tendency predisposes the
individual to make a certain end-reaction when the proper stimulus for
that reaction is present; otherwise, it predisposes him to respond to
other stimuli, which are present, by preparatory reactions that
eventually bring to bear on the individual the stimulus required to
arouse the end-reaction_.

Let us apply our formula to one more simple case. While reading in the
late afternoon, I find the daylight growing dim, rise and turn on the
electric light. The stimulus that sets this series of acts going is
the dim light; the first, inner response is a _need_ for light. This
need tends, by force of habit, to make me turn the button, but it does
not make me execute this movement in the air. I only make this
movement when the button is in reaching distance. My first {82}
reaction, rising from my chair, is preparatory and brings the button
close enough to act as a stimulus for the hand reaction. The button
within reach is not by itself sufficient to arouse the turning
reaction, nor is the need for light alone sufficient. The two
conditions must be present together, and the preparatory reaction is
such that, given the need, the other condition will be met and the
reaction then aroused.


What a Tendency Is, in Terms of Nerve Action

Very little need be added to our neural conception of a reaction in
order to get a satisfactory conception of a tendency to reaction.
Principally, we must add this fact, that a nerve center aroused to
activity does not always discharge instantly and completely into the
muscles, or into some other center, and come to rest itself. It does
so, usually, in the case of a reflex, and in other momentary
reactions; as when A makes you think of B, and B at once of C, and so
on, each thought occupying you but a moment. But a tendency means the
arousing of a nerve center under conditions which do not allow that
center to discharge at once. The center remains in a condition of
tension; energy is dammed up there, unable to find an outlet.

We have already seen what the conditions are that cause this damming
up of energy. The center that is aroused tends to arouse in turn some
lower motor center, but by itself does not have complete control over
that lower center, since the lower center also requires a certain
external stimulus in order to arouse it to the discharging point.
Until the proper external stimulus arrives to complete the arousal of
the lower center, the higher center cannot discharge its energy.

When there is an "organic state" present, such as hunger or thirst,
this may act as a persistent stimulus to the sensory nerves and
through them to the higher center in {83} question; and then we can
readily understand how it is that the center remains active until the
organic state is relieved. But where there is no such persistent
organic stimulus, as there can scarcely be in the case of the
bloodhound or of the man hurrying to a train or seeking in the crowd
for a friend, there we have to suppose that a center, once aroused to
activity and prevented from complete discharge, remains active by
virtue of energy dammed up in itself. There is pretty good
physiological evidence that this sort of thing is a fundamental fact;
for there are certain rhythmical reflexes, like scratching or
stepping, that, when started going by a momentary sensory stimulus,
keep it up for a time after the stimulus has ceased. There seems to be
no doubt that a nerve center, once aroused, may stay aroused for a
time.

The "dammed-up energy" here is not to be confused with the "stored
energy" spoken of under the head of reactions. We said, in that
connection, that a stimulus released energy stored in the organism.
That, however, was _potential_ energy, dormant within the organism
till aroused; but what we have here in mind is active or _kinetic_
energy. Stored energy is like that of coal in the bin; dammed-up
energy is like that of steam in the boiler.

Dammed-up energy in the nerve centers accounts for the persistence of
a tendency to reaction after the stimulus has ceased. It accounts for
the "delayed reaction" and similar cases. But how shall we account for
preparatory reactions? We have a nerve center in an active state,
tending to discharge into a certain lower motor center, but unable to
do so because a peripheral stimulus is necessary, in addition, in
order to arouse this lower center. Then we find the higher center
discharging into _other_ lower centers, and so giving rise to
preparatory reactions. More precisely, what we find is that the higher
center facilitates the response {84} of certain lower centers to their
proper peripheral stimuli, while inhibiting the response of other
lower centers to their appropriate stimuli. This is the same sort of
thing that we observe in all control exerted by a higher center over a
lower. It means that the higher center, besides its main line of
connection with the lower center that will give the end-reaction, has
minor lines of connection with certain other lower centers; some of
these centers it facilitates and others it inhibits. These connections
between the main and the subordinate centers may have been established
by inborn nature, or by previous training, as will be explained in
later chapters.

The action of the main center on the subordinate centers concerned in
executing preparatory reactions does not relieve the tension in the
main center. The dammed-up energy stays there till the proper stimulus
is procured for arousing the end-reaction, and then escapes through
its main channel of discharge, and the main center then finally comes
to rest.

It may fairly be urged that no violence has been done to the general
conception of a reaction by these additions, and also that with the
additions the notion of a reaction has room for tendencies or inner
adjustments. So that we conclude that stimulus-response psychology is
adequate to the job, and will do justice to all forms of human
behavior. It has a place for sensations, perceptions and thoughts, as
we saw in the preceding chapter, and it has a place also for purposes,
desires and motives generally.


Motives

In the present chapter, desirous of "keeping close to the ground", we
have said little of distinctively human motives. That will come later.
In general, a motive is a tendency towards a certain end-result or
end-reaction, a tendency which is itself aroused by some stimulus, and
which {85} persists for a time because its end-reaction is not at once
made. The end-reaction is not made at once because it can only be
aroused by an appropriate stimulus, acting in conjunction with the
motive. But the motive, persisting in its inner activity, facilitates
reactions to certain stimuli and inhibits others. The reactions it
facilitates are preparatory to the end-reaction, in that they provide
the necessary conditions for that reaction to occur, which means that
they bring to bear on the individual the necessary stimulus which can
arouse the end-reaction. The restlessness that characterizes an
individual driven by an inner motive gives way to rest and
satisfaction when the end-result is reached.

Motives range from the primitive or primal, like hunger, to the very
advanced, such as zeal for a cause. They range from the momentary,
illustrated by the need for more light in reading, to the great
permanent forces of life, like _amour propre_ and _esprit de corps_.
But the permanent motives are not always active; they sleep and are
awakened again by appropriate stimuli.

In everyday speech we are apt to use the words "motive" and "reason"
interchangeably, as in asking some one what his "motive", or what his
"reason" is for doing so and so. A motive, however, is not necessarily
a reason, nor a reason a motive. A reason is thought-out and
conscious, which a motive need not be. On the other hand, a reason
does not become a motive unless it takes hold of us and arouses a
genuine tendency towards the planned result. You may prove to me,
logically, the desirability of a course of action, but your reasons do
not necessarily make me desire it. You can give a child excellent
reasons for studying his lessons, but you have to stir some real
motive of child life in order to get action. In the highest type of
conduct, to be sure, motive and reason pull together, reason showing
the way to the goal at which motive is aimed.

{86}

EXERCISES

1. Complete the following outline of the chapter, by filling in
   main headings to fit the subordinate headings that are given below:

   A. _________

     (1) It keeps close to the facts.

     (2) It has room for introspective as well as behavior study.

     (3) It can be applied practically.

   B.  _________

    (1) A stimulus is typically external, a purpose internal.

    (2) A stimulus typically acts for a moment, a purpose persists
        for some time.

    (3) A stimulus is not directed towards a result, a purpose is
        so directed.


   C. _________

      (1) Organic or physiological states that predispose towards
          certain forms of behavior.

      (2) Inner adjustments towards certain results, without
          foresight of the results.

      (3) Conscious purpose.

   D. _________

     (1) They are aroused by stimuli.

     (2) They persist for a time.

     (3) They influence the response to other stimuli.


   E. _________

     (1) They are neural rather than chemical.

     (2) They amount to a preparation or readiness for a certain
         response.

     (3) They persist sometimes for only a few seconds, sometimes
         for many minutes at least.

   F.  _________

     (1) A whole series of acts may be set going by a single stimulus.

     (2) The series comes to an end when a certain result has been
         reached.

     (3) Each act in the series is a response to some particular
         stimulus, and yet would not be aroused by that stimulus
         except for the active adjustment towards the end-result.
{87}
     (4) The end-result cannot be reached until a particular
         stimulus helps the adjustment to arouse the end-reaction.

     (5) The preliminary acts in the series bring the required
         stimulus that can give the end-reaction.

   G. _______

     (1) It may be kept active by a continuing peripheral stimulus.

     (2) It may be unable to discharge fully because its main path of
         discharge is blocked.

   H. _______

     (1) The main center has minor connections with other
         centers, in addition to its main path of discharge.

     (2) The persisting activity of the main center influences
         other centers by way of facilitation and inhibition.

2. Fill in the blanks in the following paragraph:

   "A motive or (1) is a reaction that has not yet come off. It has
   been (2) by some stimulus, and it tends towards a certain (3),
   which however it is unable of itself to produce, but requires the
   assistance of another (4) which is not yet present. The motive
   gives rise to (5) responses, which, if (6), finally bring the
   required (7), and this, combined with the (8) arouses the (9), and
   so brings the whole (10) of acts to a close."

3. Cite cases illustrating the importance of preparatory adjustment
   (a) for securing prompt reaction, and
   (b) for securing keen observation.

4. Cite a case where some need or desire gives rise to a series of
   preparatory reactions.

5. Cite a case where a need or desire leads to the omission
   (inhibition) of acts that would otherwise have occurred.

6. What is meant by the last sentence in the chapter?

7. An experiment on the "delayed reaction". Take two sheets of
   paper, and on each write the letters A, B, C, D, E, and F,
   scattering them irregularly over the sheet. The task, in general,
   is now to take aim at one of the letters, while your hand, holding
   a pencil, is raised to the side of your head, and then to close the
   eyes and strike at the letter aimed for. First aim at A, and mark
   the point hit with an a, then the same with B, and so on. With the
   first sheet, strike as soon as you have got your aim and closed
   your eyes; but with the second sheet, aim, close your eyes, and
   count ten slowly before striking, keeping the eyes closed till the
   stroke has been made. Two sorts of observation should now be made:
   first, introspective--record at once what you can of the way you
   kept your aim during the delay. Second, objective--measure the
   errors, and determine how much the delay affected your aim. What
   conclusions can you draw from the experiment?

{88}

REFERENCES

On the "delayed reaction", see Walter S. Hunter, "The Delayed Reaction
in Animals and Children", _Behavior Monographs_, No. 6, 1913. A brief
summary of this work can also be found in Hunter's _General
Psychology_, 1919, pp. 31-33.

On the homing of pigeons and terns, see Watson and Lashley, _An
Historical and Experimental Study of Homing_, published by the
Carnegie Institution of Washington, 1915.

Interesting examples of changed organic states affecting the behavior
of unicellular animals are given by Jennings in his _Behavior of the
Lower Organisms_, 1906, and by Margaret F. Washburn in _The Animal
Mind_, 2nd edition, 1917, pp. 246-257.


{89}


CHAPTER V

NATIVE AND ACQUIRED TRAITS

SOME RESPONSES ARE PROVIDED BY NATURE, WHILE
OTHERS HAVE TO BE LEARNED BY EXPERIENCE

John Doe is a strongly built man, over six feet high, with big bones
and muscles, erect, vigorous, with plenty of color in his face,
dark-haired, blue-eyed, clean-shaven, with a scar on his cheek, broad
face and large ears. He is easy-going, even-tempered, fond of children
and also of women, rather slangy and even profane in his talk, has a
deep, sonorous voice and can carry the bass in a chorus. He is handy
with tools, can drive or repair an automobile, is a fairly good carpet
salesman, but much prefers out-of-door work. Rather free in spending
his money, he has never run into debt except on one occasion, which
turned out badly for him. Which of these traits of John Doe are native
and which are acquired? How far are his physical, mental and moral
characteristics the result of his "original nature" and how far have
they been ingrained in him or imposed upon him by his training and
environment?

The distinction between native and acquired is clearest in the field
of anatomy. Hair color and eye color are evidently native, and so, in
the main, is the size of the body, though undoubtedly growth may be
stunted by poor nutrition, and the individual fail to reach his
"natural" height and weight. On the other hand, scars, tan, and the
after-effects of disease or injury, are evidently acquired. Of
movements, the native character of the reflexes has already been
noted, and it is clear that skill in handling tools or {90} managing
the voice is learned, though the individual may have a natural
aptitude for these performances. Temperament and emotional traits we
usually think of as belonging to a man's "nature", though we have to
admit that a naturally cheerful disposition may be soured by ill
treatment. On the other hand, while we reckon habits, such as
profanity, or free spending, or an erect carriage, as belonging with
the acquired traits, we know that some natures are prone to certain
habits, and other natures to other habits. Thus the effects of
"nature" and "experience" are almost inextricably interwoven in the
behavior of an adult person.

Difficult as it certainly is to separate the native from the acquired
in human action, the attempt must be made. We cannot dodge so
fundamental a problem. Scientifically it is important as the
starting-point of a genetic study; we must know where the individual
starts in order to understand the course of his development.
Practically it is important because there is reason to believe that
native traits are deeply seated and not easily eradicated, even though
they can be modified and specialized in different ways. If a habit is
not simply a habit, but at the same time a means of gratifying some
natural tendency, then it is almost imperative to find a substitute
gratification in order to eliminate the habit. The individual's nature
also sets limits beyond which he cannot be brought by no matter how
much training and effort; and this is true of mental development as
well as of physical.


The Source of Native Traits

"Native" means a little more than "congenital." A child may be born
blind, having been infected by disease germs shortly before birth; he
may be congenitally an idiot because of head injury during a difficult
birth; or his mentality may have been impaired, during his uterine
life, by {91} alcohol reaching his brain from a drunken mother. Such
traits are congenital, but acquired. Native traits date back to the
original constitution of the child, which was fully determined at the
time when his individual life began, nine months before birth. The
"fertilized ovum", formed by the combination of two cells, one from
each of the parents, though microscopic in size and a simple sphere in
shape, somehow contains the determiners for all the native or
inherited traits of the new individual.

It is very mysterious, certainly. This microscopic, featureless
creature is already a human individual, with certain of its future
traits--those that we call "native"--already settled. It is a human
being as distinguished from any other species, it is a white or
colored individual, male or female, blonde or brunette, short or tall,
stocky or slender, mentally gifted or deficient, perhaps a "born"
musician or adventurer or leader of men. These and all other native
traits are already determined and latent within it; and the only
question, regarding such traits, is whether the environment is going
to be such as to enable this young individual to live and mature and
unfold what is latent within it.


Reactions Appearing at Birth Must Be Native

For the first few months of the individual's existence, sheltered as
it is within the mother's body, there is no chance for any
acquisition, except of certain abnormalities such as were alluded to
above. What occurs during this prenatal period is natural development,
not learning or any effect of experience. The traits displayed by the
new-born child are, accordingly, native traits. His breathing, crying,
starting at a noise, squirming, stretching, grasping, sucking and
swallowing, and other movements made from birth on, are to be counted
as native reactions, that is to say, as {92} reactions executed by
sensory, muscular and nervous machinery that have become ready for use
by the mere process of natural growth. This is the first and clearest
sign of a native trait, that it shall appear at birth.


Reactions That Cannot Be Learned Must Be Native

But native traits continue to make their appearance as the child's
development proceeds after birth. Inherited anatomical traits, like
stature and build, hair color, beard, and shape of nose, though
certainly determined by native constitution, do not fully make their
appearance till maturity. In fact, what does maturity mean, except
that the natural characteristics have finally reached their complete
development? And it is as true of internal structure as of external,
that natural development, far from being complete at birth, keeps on
till maturity. The neurones continue to grow, and their synapses in
the nerve centers to become closer knit, just by virtue of natural
growth; and thus reflex arcs, and other reaction machinery, one by one
reach the ready-to-use stage during the individual's growing-up,
especially during the first few years. With the growth to a functional
condition of their sensori-neuro-muscular mechanisms, mental and motor
reactions that are native, though not present at birth, make their
appearance. The native intelligence of the child gradually unfolds,
likewise his special native "gifts" and his inherited emotional and
impulsive traits.

Of course it is more difficult to make sure that a trait is native
when it does not appear till some time after birth, for the chance of
acquiring it by a process of learning has to be taken into account. If
you can so control the conditions under which the young individual
grows as to eliminate the possibility of learning a certain act, then
you can {93} make sure whether the act is acquired or provided by the
native constitution.


Experimental Detection of Native Reactions

Take the question whether birds learn to fly or simply come to fly
when their natural development has gone far enough. The newly hatched
bird cannot fly; its muscles are not strong enough, its wings are not
feathered, and its nerve mechanism for cooerdinating the wing movements
has still some growth to make before being ready for use. But, under
ordinary conditions, the young bird has some chance to _learn_ flying,
by watching the old birds fly and by trying and gradually getting the
motion. The old birds, after a time, push the young ones from the nest
and seem, to our eyes, to be teaching them to fly. Experiment enables
us to decide the question. One of the earliest experiments in animal
psychology was made by Spalding in 1873. He took newly hatched birds
from the nest and shut each one separately in a little box that gave
it no chance to stretch its wings or to see other birds fly. Here he
fed and cared for them till the age at which flying usually begins,
and then released them. Off they flew, skilfully managing wings and
tail, swooping around the trees and soon disappearing from sight. A
very successful experiment!--and conclusive. The little birds had had
no chance to learn to fly, yet they flew. Flying must have come to
them in the natural course of growth.

Compare with this experiment another one no less successful, though it
turned out differently. To discover whether the song of the oriole is
fixed by nature or learned by imitation, Scott took some little ones,
just hatched, and brought them up away from older birds. After a time,
when growth had advanced to a certain stage, the birds began {94} to
sing. The elementary notes and rattles characteristic of the oriole
made their appearance, but were combined in unusual ways, so that the
characteristic song of the oriole did not appear, but a new song. When
these birds had grown up in the laboratory, other new-hatched orioles
were brought up with them, and adopted this new song; so that the
laboratory became the center for a new school of oriole music. The
experiment showed that the elements of the oriole's song were provided
by nature, while the combination of these elements was acquired by
imitation.

Probably this last is about the result one would get in the analogous
case of human speech, if a similar experiment should be tried on
children. Without an experiment, we have certain facts that point to a
conclusion. The child uses his vocal organs from birth on; and before
he reaches the age when he imitates the speech of others, he produces
various vowels and consonants, and even puts them together into simple
compounds, as "da-da" and "goo-goo." So far, deaf children do about
the same as others, affording additional evidence that so much of
speech is native. To get real speech, however, further combinations of
the speech movements must be made, and the combinations (words) must
have meaning attached to them. These higher achievements are evidently
the result of learning, since the child uses the words that it hears
spoken, and attaches the same meanings to them as people do about it.
The child comes to speak the language of those about it, without
regard to the speech of its ancestors. His "native language" is
therefore acquired, though the elements of vocal utterance are truly
native, and apparently are alike all over the world without regard to
the various languages spoken.

{95}

Is Walking Native or Acquired?

As another example of this same general problem of distinguishing
native from acquired reactions, and of the kind of evidence that
throws light on the problem in the absence of direct experiment, let
us consider the child's walking. Does the child learn to walk, or does
it simply _come_ to walk when its natural development has gone far
enough? We think the child learns to walk because it begins very
imperfectly and usually takes several weeks before it can be described
as really walking of itself. We even think we teach it to walk, though
when we examine our teaching we soon convince ourselves that we do not
know _how_ we walk, and that what we are doing with the baby is to
stimulate and encourage him to walk, protect him from hurting himself,
etc., rather than teaching him as we later teach the child to write.
An experiment to settle the matter might be conducted along the lines
of Spalding's experiment on the young birds. We might prevent the baby
from making any attempt to walk till it had fully reached the normal
age for walking, and then turn it loose and see whether it walked of
itself.

Such an experiment has never been made under strict laboratory
conditions; but here is a well-attested case that approximates to an
experiment. A little girl of seven months, a very active child, seemed
to want to get on her feet; but the doctor decided that her feet were
too small to use, and directed that she be put back in long dresses.
For four months she was kept in long dresses, and great care was
exercised never to place her on the floor without them. Then, one day,
she was set down without her dress, and immediately up she got and
walked; and from that moment she was very agile on her feet.

Another rather different case, but tending towards the {96} same
conclusion, is that of a little girl who, in contrast to the
preceding, gave her parents some anxiety because, up to the age of
seventeen months, she wouldn't walk. She would stand holding on, but
not trust herself to her feet alone. One noon her father came in from
his work and, removing his cuffs, laid them on the table. The little
girl crept to the table, and raised herself to a standing position,
holding on to the table. She then took a cuff in one hand, and
inserted the other hand into it, thus, for the first time, standing
unsupported. She put on the other cuff in like manner, and then
marched across the room, as proud as you please. For a few days she
could walk only with cuffs, but after that was able to dispense with
them. There are a few other cases, differing in details, but agreeing
on the main point, that the baby walked well on its first trial and
went through nothing that could properly be interpreted as a process
of learning.

It would really be very surprising if the human infant were left to
learn locomotion for himself, while all other animals have this power
by nature. Just because the human infant matures slowly, and learns a
vast deal while maturing, is no reason for overlooking the fact that
it does mature, i.e., that its native powers are gradually growing and
reaching the condition of being ready for use. The most probable
conception of "learning to walk," in the light of the evidence, is
about as follows. At the age when the child's bones and muscles have
become strong enough for walking, the nerve connections for
cooerdinating this complex movement have also just about reached the
stage of development when they are ready for business. The numerous
synapses in the nerve centers that must be traversed by nerve currents
in order to arouse the muscles to this particular act are not, we may
suppose, all ready at the same instant, and it takes some little time
for them to pass from {97} the stage when they will first conduct to
the stage when, having grown more, they conduct perfectly. In other
words, the neural mechanism for walking can function imperfectly
before it can function perfectly. It takes several weeks of growth to
pass from the barely functional condition to the fully functional
condition; and it is during these weeks that the child seems to be
learning to walk, while really his exercise of the partially developed
neural mechanisms has no effect except to hasten their growth to some
extent.


Universality as a Criterion of Native Reactions

The fundamental sign or criterion of a native trait, in accordance
with what we have been saying, is that it shall make its appearance
when there has been no chance to acquire it through experience. This
is the one perfect criterion; but unfortunately it cannot always be
applied, especially with a slowly maturing and much-learning species
such as the human. We need other criteria, and one of some value is
the criterion of _universality_.

Consider, for example, the attraction between the sexes, and ask
whether this represents a native tendency, or whether each individual
acquires it, as he does his "native language", by learning from his
elders. Before the body reaches sexual maturity, there has been
abundant opportunity for the quick-learning child to observe sex
attraction in older people. Yet it is highly improbable that the
liking for the other sex which he begins to show strongly in youth is
simply an acquired taste. It is improbable because the attraction
between the sexes is so universal not only among mankind but among
birds and mammals and, indeed, practically throughout the animal
kingdom.

Fighting is a similar case. Not so universal as the sex instinct, it
still appears almost universally among birds and mammals.

{98}

The human individual is an animal, and some of his native traits are
universal among animals. He is a vertebrate, and some of his traits,
though not present in all animals, are universal among vertebrates. He
is a mammal, with mammalian traits; a primate, with primate traits; a
man with human traits; a Chinaman or Indian or European with racial
traits; belongs to a more or less definite stock or breed within the
race, and possesses the traits that are common to members of that
stock; and the same with family traits. The criterion of universality,
in the light of these facts, comes down to this: that _when all
individuals having the same descent show a trait in common, that
trait is to be regarded as belonging to their native
constitution--unless evidence can be brought forward to the contrary_.

Smoking is universal among many Malay peoples, but we know, as a
historical fact, that it was introduced among them after the discovery
of America, not very many generations ago. Superstition is universal
among some peoples, but we see the superstitious beliefs and practices
taught by the older to the younger generation. Similarly with any
specific language. It may very well be true in such cases that the
universal practice appeals to some native tendency of the people; but
the specific practice is handed down by tradition and not by
inheritance.


Some Native Traits Are Far from Being Universal

Though the universality of a trait creates a certain presumption in
favor of its being native, the opposite is not always true, for a
trait may be native and yet appear in only a fraction of those who
have a common descent. Eye color is certainly native, and yet one of
two brothers may have blue eyes and the other brown. Mental deficiency
runs in families, but usually some members of such families have {99}
normal mentality. Genius is almost certainly a native trait, but it is
the reverse of universal. The fact is that, along with certain traits
that appear in all, the native constitution of a stock provides also
for traits that appear only sporadically. Enough has been said to show
that the criterion of universality is one that needs to be applied
with judgment.


Why Acquired Traits Differ from One Individual to Another

Acquired traits are on the whole much less universal, much more
individual, than native traits. They are readjustments of the
individual to environmental conditions; and, as the environment
varies, so the adjustments vary, even when native traits are the same.
Acquired traits are often specializations of the native traits, as any
specific language is a specialization of the vocal utterances that are
native and common to all men, and as the peculiar gait of an
individual is a specialization of the universal walking movement. The
gait differs with the environmental differences to which the
individual has adapted himself, and will be different in one who has
been accustomed to walk over rough ground and in one whose walking has
been done on the city streets.

_Acquired traits are not independent of native, but are developed on
the basis of the native traits_. They are acquired not by laying aside
native tendencies and working out something entirely new, but by
acting in accordance with the native tendencies and making such
readjustments as the environment demands. The acquisition of mental
traits is accomplished by the process of _learning_, and we shall
later have abundant occasion to examine it in more detail.

{100}

What Mental Traits Are Native?

For the present, let us simply take a brief survey of the mental
field, and notice what types of reactions are native and what
acquired. On the motor side, the reflexes are native, while habitual
and skilled movements are acquired. On the sensory side, nature
provides the use of the sense organs and the sensations immediately
resulting from their stimulation. The baby responds to touch, warmth,
cold, sound and light as soon as it is born, or practically so, and
undoubtedly has the corresponding sensations. In other words, the
rudiments of seeing, hearing, etc., are provided by nature. But when
we say, "I see a dog" we mean more than that we are getting certain
visual sensations; we mean that we see a known object or known sort of
object. This implies recognition of the object, either as an
individual thing or as one of a class; and this the baby can scarcely
be supposed to do at first. He sees the dog to the extent that he
responds by visual sensations to the light coming from the dog, but
not to the extent that he recognizes the dog as a dog. In short, the
_meanings_ of sensations are acquired, though the sensations
themselves are native.

Things come to be known by use of the senses, and when thus known are
not only recognized when present, but also remembered and thought of
when they are not present to the senses. Such memories and items of
knowledge, dependent as they are on experience, are to be reckoned
among the acquired reactions. Ideas or conceptions of things also
belong here.

Of the emotions, some are called "primary" or native--anger and fear
are examples--while others result from the compounding of these
primary emotions and are therefore acquired. As people and things come
to be known, emotional reactions become attached to them, and give
what {101} are often named "sentiments", such as love for this person,
contempt for that one, family pride, patriotism. These sentiments,
bound up as they are with knowledge and ideas, are certainly acquired.

Closely akin to the primary emotions are the native impulses, as the
impulse to eat, to cry, to laugh, to escape from danger, to resist
external compulsion and to overcome obstacles. The native impulses are
the raw material out of which the numerous acquired desires of child
and adult are formed. One sort of native impulse is the impulse to
notice or pay attention to certain sorts of stimuli. These native
interests of the child give birth to the various specialized interests
of the adult. The baby's attention to a bright light represents a
native interest; the older child's fixing his eyes on a dark brown
piece of chocolate represents an acquired interest which has developed
in a way that is easy to understand.

Finally, we must count among the native traits of the individual his
inherited aptitudes for certain kinds of work. One child shows a
natural aptitude for music, another for acting, another for
mathematics, another for mechanical things, another for language, and
so on. As any of these "natural gifts" is present in some degree in
nearly all members of the human family, and not to anything like the
same degree in animals, they are the characteristically human traits.
It is on the basis of such native aptitudes that each individual
proceeds, through the processes of learning, to build up his various
acquired abilities, such as the ability to sing, to speak a certain
language, to add, to work with tools, to perform athletic feats, and
to take part in social activities of various sorts.

Our next task will be to examine more closely the native equipment of
man, and after that to take up the process of learning, which is the
way reactions are acquired. First the native, then the acquired. The
acquired is based upon {102} the native. Acquired reactions are indeed
so numerous that we cannot attempt even to list them all, let alone
examine each one separately; but we can at least study the _way_ in
which they are acquired. Native reactions are much less numerous, so
that the student may hope to obtain a fairly comprehensive survey of
this field, though, of course, without much detail.

The general plan of this book, then, is as follows. Up to this point,
it has been providing a stock of methods and general conceptions to
serve as tools in psychological study: consciousness and behavior, the
introspective and objective methods, reactions and tendencies to
reaction, native and acquired, and the part played by the nervous
system. Next comes a survey of reactions provided by the native
constitution, and after that a study of the process of learning or
acquiring reactions. Finally, there are several chapters devoted to
such topics as imagination, reasoning and will, which are ways in
which the individual utilizes his whole equipment, native and
acquired, in meeting the exigencies of life.

{103}

EXERCISES

1. Outline the chapter.

2. When does the individual come into existence as an individual?
   When does he begin to acquire traits? How long does he continue to
   unfold his native traits, and how long does he continue to acquire
   traits?

3. Which of the following elements of spoken language are native,
   and which acquired?

   (a) Production of voice by the vocal cords and air blast from the lungs.

   (b) Varying the voice in loudness.

   (c) Varying the voice in pitch.

   (d) Production of vowels by different positions of the mouth.

   (e) Production of consonants by lip and tongue movements.

   (f) Combination of vowels and consonants into words.

   (g) Combination of words into idioms and grammatical sentences,

   (h) Attachment of meanings to words.

   (i) Sweet-toned voice.

   (j) Nasal twang.

   (k) Fluency in speaking.


4. In each of the following reactions, decide whether the connection
   of stimulus and response is probably native or acquired:

         Stimulus          Response

   (a) a sudden noise      starting

   (b) a bright light      blinking

   (c) a bright light      shading your eyes

   (d) cold                putting on coat

   (e) cold                shivering

   (f) sight of a ball     reaching for it

   (g) ball in the hand    throwing it

   (h) slipping            righting yourself

   (i) row of objects      counting them

   (j) insulting language  anger


REFERENCES

Edward L. Thorndike, in Chapter I of his _Educational Psychology,
Briefer Course_, 1914, gives a general survey of the native factors in
mental life and behavior.

{104}

Hollingworth and Poffenberger, in their _Applied Psychology_, 1917,
devote Chapters II and III to the matter of mental heredity.

Norsworthy and Whitley, in their _Psychology of Childhood_, devote
Chapters I and II to "original nature".

C. B. Davenport, in his _Heredity and Eugenics_, presents evidence of
the importance of heredity in determining mental and moral traits.

Yerkes and Bloomfleld, in a short article in the _Psychological
Bulletin_ for 1910, Vol. 7, pp. 253-263, under the title, "_Do Kittens
Instinctively Kill Mice?_", furnish a good illustration of the method
employed in distinguishing native from acquired reactions.

{105}


CHAPTER VI

INSTINCT


CONDUCT AS DETERMINED BY NATIVE REACTION-TENDENCIES

Instinct is native behavior. It is contrasted with habit, knowledge,
or anything in the way of learned reactions. When the mother wasp
gathers a store of food suitable for young wasps, lays eggs beside the
food and covers the whole with a wall of mud, we know that her
behavior is instinctive because she has had no possible chance to
learn from older wasps. She has never seen a wasp's nest made, for
when the last preceding crop of nests was being made she was herself
an unhatched egg. Therefore, she cannot possibly know the use of the
nest with its eggs and store of food. She has no "reason" for building
the nest, no ulterior purpose, but is impelled to build the nest,
simply and solely for the sake of doing just that thing. Thus instinct
is contrasted with calculated or reasoned action as well as with
learned action. Calculated action is based on knowledge of cause and
effect, and this knowledge is acquired by the individual in the course
of his experience; but instinct is not based on the individual's
experience, but only on his native constitution.

The case of the baby eating is exactly the same as that of the wasp.
The baby has not learned to eat, he knows nothing of the use of food
and therefore has no ulterior purpose in eating, he does not reason
about the matter, but eats simply because hunger is a native impulse
to eat. {106} Eating is an end in itself to a hungry baby, and not a
means to some further end; and that is what eating continues to be
even to the hungry adult, however much he may learn about the use of
food in maintaining life. From a broad philosophical point of view,
instinct may be seen to work towards some great end, such as the
preservation of the individual or the propagation of the race, but
from the individual's own point of view, it is directed simply towards
the performance of some particular act, or the accomplishment of some
particular result.

If instinct, as a collective term, means native behavior, "an
instinct" is a unit of such behavior. Or, it is some unit of native
organization that equips the individual to behave in a certain way.
Different species of animals have different instincts, i.e., they are
differently organized by nature. The differences of organization lie
partly in the equipment of sense organs, partly in the equipment of
motor organs, and partly in the nerves and nerve centers that, being
themselves aroused by way of the sense organs, in turn arouse the
motor organs.

The dependence of instinct on sensory equipment becomes clear when we
think of animals possessing senses that human beings lack. The
instinct of dogs to follow the scent depends on their keen sense of
smell. Bees have something akin to a sense of taste in their feet, and
follow their own trails by tasting them. Fishes have special sense
organs along their sides that are stimulated by water currents, and it
is in response to this stimulus that the fish instinctively keeps his
head turned upstream.

The dependence of instinct on motor equipment is still more obvious.
The flying instinct of birds depends on the possession of wings, and
the swimming instinct of the seal depends on the fact that his limbs
have the peculiar form of flippers. The firefly instinctively makes
flashes of light, {107} and the electric eel instinctively discharges
his electric organ and gives his enemy a shock.

But the core of an instinct is to be sought in the nerve centers,
since it is there that the cooerdination of the muscles is
accomplished. A wing or flipper would be of no use unless its muscles
were excited to action by the nerve centers, and it would be of very
little use unless the nerve centers were so organized as to arouse the
muscles in a certain combination, and with a certain force and rhythm.
In terms of the nervous system, an instinct is the activity of a team
of neurones so organized, and so connected with muscles and sense
organs, as to arouse certain motor reactions in response to certain
sensory stimuli.


The Difference Between an Instinct and a Reflex

What we have said regarding instinct thus far could equally well be
said of reflex action. A reflex is a native reaction, and it is taken
care of by a team of neurones in the way just stated. We might speak
of a reflex as "instinctive", using this adjective as equivalent to
"native"; but we should shrink for some reason from speaking of the
pupillary reflex to light as an instinct, or of the "knee jerk
instinct", or the "swallowing instinct", or the "flexion instinct".
There is some difference between the typical reflex and the typical
instinct, though it is not very obvious what the difference is.

The typical reflex is a much simpler act than the typical instinct,
but it is impossible to separate the two classes on this basis. At the
best, this would be a difference of degree and not of kind. Among
reflexes, some are simpler than others, but even the simplest is
compound in the sense of being a cooerdinated movement. The knee jerk
is simpler than the flexion reflex, and this is simpler than the
scratch {108} reflex, which consists of a rapid alternation of flexion
and extension by one leg, while the other is stiffly extended and
supports the trunk. Coughing, which would be called a reflex rather
than an instinct, consists of a similar alternation of inspiration and
forced expiration, and swallowing consists of a series of tongue,
throat and gullet movements. These compound reflexes show that we
cannot accept the simple definition that is sometimes given for an
instinct, that it is a compound of reflexes. Such a definition would
place coughing and swallowing among the instincts, and so do violence
to the ordinary use of the word. In point of complexity, we find a
graded series ranging from the pupillary reflex at one extreme to the
nesting or mating instinct at the other, and no sharp line can be
drawn on this score between the reflexes and the instincts.

Another distinction has been attempted on the basis of consciousness.
Typically, it may be said, a reflex works automatically and
unconsciously, while an instinct is consciously impulsive. The reflex,
accordingly, would be an unconscious reaction, the instinct a
conscious reaction. But this distinction also breaks down on
examination of cases. The pupillary reflex, to be sure, is entirely
unconscious. But the flexion reflex is a little different. When
unimpeded, it occurs so promptly that we are scarcely aware of the
painful stimulus before the reaction has occurred. But let the
reaction be hindered--either voluntarily or, for instance, by the foot
being seized and held--and a strong conscious impulse is felt to pull
the leg away; so that here the flexion reflex would belong among the
instincts, according to the proposed distinction.

Similar remarks would apply equally well to coughing, since a strong
impulse to cough is felt if the coughing movement is checked.
Sneezing, a protective reflex, is usually a slow reaction, giving time
for a conscious impulse to {109} sneeze before the reaction takes
place. The same is true of scratching and of swallowing, and of a
number of other reflexes. In short, it is impossible to draw a
satisfactory line between reflexes and instincts on the basis of
conscious impulse.

These cases point the way, however, to what is probably the best
distinction. It was when the flexion reflex was _delayed_ that it
began to look like an instinct, and it was because sneezing was a
_slow_ response that it had something of the character of an instinct.
Typically, a reflex is a prompt reaction. It occurs at once, on the
occurrence of its stimulus, and is done with. What is characteristic
of the instinct, on the contrary, is the persisting "tendency", set up
by a given stimulus, and directed towards a result which cannot be
instantly accomplished.


An Instinct Is a Native Reaction-Tendency

We would propose, then, to consider an instinct as an inner
adjustment, or tendency to reaction. It is this, rather than just a
reaction. When a stimulus promptly arouses a reaction, and that ends
the matter, we speak of reflex action--provided, of course, the
connection between stimulus and response is native. But when a
stimulus sets up a tendency to a reaction that cannot be immediately
executed, or towards an end-result which cannot immediately be
reached, and when the tendency so aroused persists for a time in
activity, and gives rise to preparatory reactions, then we speak of
instinct.

The "broody" hen makes a good picture of instinct. When in this
condition she responds to a nestful of eggs, as she does not at other
times, by sitting persistently on them and keeping them covered. She
is in a certain "organic state" that facilitates this response. In the
absence {110} of any nestful of eggs, she shows a peculiar restless
behavior that indicates to one who knows hens that this one "wants to
set." The tendency that has been awakened in her cannot be satisfied
by any momentary act, but persists and governs her actions for a
considerable period.

The nesting instinct of birds affords a still more complete example.
The end-result here, the finished nest, cannot be instantly had, and
the pair of birds keep on gathering materials and putting them
together until this end-result is present before their eyes. It is not
necessary to suppose that the birds have any plan or mental image of
what the nest is to be like; probably not. But their state, in the
nest-building season, is such that they are impelled to build, and the
tendency is not quieted till the completed nest is there.

The mating instinct, in unsophisticated members of the human species,
is another perfect example. So is the hunting instinct in a dog; when
this instinct is aroused, the animal makes a lot of movements of
various sorts, responses to various particular stimuli, but evidently
these movements are not sufficient to quiet the tendency, for they
continue till the prey is captured. The behavior of a gregarious
animal when separated from his fellows shows the same sort of thing.
Take a young chick out of the brood and fence it away from the rest.
It "peeps" and runs about, attacking the fence at different points;
but such reactions evidently do not bring satisfaction, for it varies
them until, if a way out of the inclosure has been left, it reaches
the other chicks, when this series of acts terminates, and gives way
to something quite different, such as pecking for food.

The persisting tendency does not produce the series of movements all
by itself, but, as was explained in speaking of tendencies in general,
cooeperates with sensory stimuli in producing them. Clearly enough, the
nest-building bird, {111} picking up a twig, is reacting to that twig.
He does not peck at random, as if driven by a mere blind impulsion to
peck. He reacts to twigs, to the crotch in the tree, to the half-built
nest. Only, he would not react to these stimuli unless the nesting fit
were on him. The nest-building tendency favors response to certain
stimuli, and not to others; it facilitates certain reactions and
inhibits others. It facilitates reactions that are _preparatory_ to
the end-result, and inhibits others.


Fully and Partially Organized Instincts

Insects afford the best examples of very highly organized instincts.
Their behavior is extremely regular and predictable, their progress
towards the end-result of an instinct remarkably straightforward and
sure. They make few mistakes, and do not have to potter around. By
contrast, the instincts of mammals are rather loosely organized.
Mammals are more plastic, more adaptable, and at the same time less
sure; and this is notably true of man. It would be a mistake to
suppose that man has few instinctive tendencies; perhaps he has more
than any other creature. But his instinctive behavior has not the
hard-and-fast, ready-made character that we see in the insects. Man is
by all odds the most pottering, hem-and-hawing of animals. Instinct
does not lead him straight to his goal, but makes him seek this way
and that till he finds it. His powers of observation, memory and
thought are drawn into the game, and thus instinct in man is
complicated and partly concealed by learning and reasoning.

For example, when an insect needs a nest, it proceeds in orderly
fashion to construct a nest of the pattern instinctive to that species
of insect; but when a man needs a home, he goes about it in a
variable, try-and-try-again {112} manner, scheming, experimenting,
getting suggestions from other people, and finally producing--a
dugout, a tree house; a wigwam, a cliff dwelling--something that
differs altogether from many other human habitations, except in the
fact that it is a habitation and thus satisfies a need which is
undoubtedly as instinctive in man as in the insect.

A fully organized instinct is one where the necessary preparatory
reactions are linked up closely with the main reaction-tendency, so
that, once the main tendency is aroused to activity, the preparatory
reactions follow with great sureness. The main team of neurones is
closely connected with the subordinate teams that give the preparatory
reactions; and these connections do not have to be acquired by
experience and training, but are well formed by native growth. Just
the right preparatory reactions are linked to the main tendency, so
that the whole series of acts is run off with great regularity.

In a loosely organized instinct, the main tendency is not firmly
linked with any specific preparatory reactions, but is loosely linked
with a great many preparatory reactions, and so gives quite variable
behavior, which, however, leads on the whole towards the main goal.

While a creature under the spell of a fully organized instinct is
busy, one driven by a loosely organized instinct may be better
described as restless. He tries this thing and that, and goes through
the kind of behavior that is called "trial and error". A closely knit
instinct, then, gives a perfectly definite series of preparatory
reactions, while a loosely organized instinct gives trial and error
behavior. We shall see later how trial and error furnishes a starting
point for learning, and how, in an animal that can learn, those among
the trial-and-error reactions that are actually preparatory to the
end-result become firmly attached to the main tendency, so that what
was by native constitution a loosely {113} organized instinct may
become, through the individual's experience, a closely organized
habit. If a man has occasion to build himself many homes, he comes,
after a while, to build almost as uniformly and surely as an insect.


Instincts Are Not Ancestral Habits

The theory of inheritance of acquired traits has gone by the board;
biologists no longer accept it. Such traits as an individual's tanned
skin acquired by living in the tropics, horny hands acquired by hard
labor, immunity to measles acquired by having measles, big muscular
development acquired by gymnastics, are not transmitted by heredity to
the children of the individual who acquired these traits.

Nor are acquired behavior traits transmitted by heredity. Learned
reactions are not so transmitted, knowledge is not, acquired skill is
not. Learn to cook, to typewrite, or pilot an airplane as perfectly as
possible, and your child will still have to learn all over again. You
may make your experience valuable to him by _teaching_ him, but not in
the way of heredity.

Language affords a good test of this matter. A child's parents, and
all his ancestors for many generations, may have spoken the same
language, but that does not relieve the child of the necessity of
_learning_ that language. He does not inherit the language habits of
his ancestors. He has no native tendency to say "dog", or "chien", or
"hund", on sight of this animal. Here in America we have children born
of stocks that have spoken foreign languages for many generations; but
English becomes their "native tongue" after a generation or two here,
that is to say, as soon as the child hears English from infancy.

In short, there is no likelihood whatever that any instinct {114} ever
originated out of a habit or learned reaction. If we could believe it
had so originated, that would furnish an easy explanation of the
origin of an instinct; but it is contrary to all the known facts.


Instincts Not Necessarily Useful in the Struggle for Existence

Some of the best-known instincts, such as feeding or mating--or
hunting, or flight from danger, or the hibernation of frogs--are so
essential for the survival of the individual or the propagation of the
next generation that we tend to assume that all instinctive behavior
has "survival value", value, that is, towards the survival of the
individual or of the race. But this is an assumption, and it seems not
to be borne out by actual observations of instinctive behavior, since,
along with the definitely useful reactions, others occur that would
seem to have no survival value. Perhaps the crowing of the rooster at
dawn would be a case in point; or the elaborate bowing that is
observed in some kinds of birds. And there are the less definite,
rather random movements of squirming, kicking, running about,
wrinkling up the face, etc., that appear in young animals. We may well
hesitate before definitely asserting that these movements are of no
use for survival, but at least their use is not obvious, and there is
no reason for assuming that all instinctive behavior must necessarily
be useful.

To be sure, the "struggle for existence" would eliminate individuals
who behaved in ways that seriously handicapped them in procuring food
or escaping from enemies; and therefore we should not expect to find
really harmful instincts preserved in the race. But a mode of behavior
might be neutral in this respect, or even slightly disadvantageous,
and yet not be weeded out unless the struggle for existence were very
keen.

{115}

The main point is that the psychologist should take instinctive
behavior as he finds it, and not allow himself to be prejudiced by the
assumption that instinct must necessarily be useful. That has to be
shown in each case, not assumed at the outset.


The So-called Instincts of Self-preservation and of Reproduction

You will hear it stated, by some, that there are just two instincts,
and that all instinctive behavior belongs under the head of one or the
other of these two. The one is the instinct to preserve one's
individual life, and the other is the instinct to propagate the
species. Mating, nesting and care of the young come under the
reproductive instinct, while feeding, flight from danger, and shunning
extreme heat or cold are modes of self-preservation. This seems
logical enough, but it is very bad psychology. It amounts to a
classification of native reactions from an external point of view,
without any consideration of the way the individual is organized.

Perhaps the most obvious objection to these two supposedly
all-inclusive instincts is found in what has just been said, to the
effect that some instinctive behavior has no known survival value.
This amounts to saying that some instincts do not serve either the
preservation of the individual or the propagation of the species; and
such a statement is probably true, especially of human instincts.

But even if this objection should not hold, there is another, more
radical one. Neither of these two big "instincts" is a behavior unit
in any sense. Take the "instinct of self-preservation", for example.
It would certainly have to include both feeding and escape from
danger. But feeding and flight from danger do not belong in a single
series {116} of acts; they are two distinct series, and represent two
distinct tendencies. So distinct are they that, as we shall see in the
next chapter, they are antagonistic. If the danger-avoiding tendency
is aroused, the whole feeding and digestive activity is checked for
the time being. The two instincts are antagonistic, in their actual
operation; throw one into action, and you throw the other out. It is
only from an external point of view that the two can be classed
together; in the organization of the individual they are entirely
separate.

Not much different is the "instinct of reproduction". In birds, to be
sure, there is a fairly continuous series of reactions, that begins
with mating, continues with nesting, laying eggs and incubating them,
and ends in the care of the young birds. But in mammals there is no
such continuous series of reproductive acts, but mating comes to a
close and an interval elapses in which there is no behavior going on
that has anything to do with reproduction.

Before giving a detailed list of the various human instincts, we shall
do well to consider emotion, which is closely bound up with instinct.


{117}

EXERCISES

1. Outline the chapter.

2. Explain the differences between these three;

   Action governed by instinct.

   Action governed by habit.

   Action governed by deliberation.

3. What is the objection to each of the following expressions?

   (a) "The ex-soldier instinctively saluted when he met an officer
       in the street."

   (b) "The bee knows by instinct how to construct the honeycomb."

4. Why is it so difficult to find a valid distinction between instinct
   and reflex action?

5. Why are instincts more universal and uniform than habits?

6. How is instinct an important matter to consider in a study of
   human motives?

7. Show how the behavior of a hungry child of six or eight years
   fits the picture of a "loosely organized instinct".


REFERENCES

William James in his _Principles of Psychology_, 1890, has a very
stimulating chapter on instinct, in Vol. II, pp. 383-441.

John B. Watson, in Chapters IV and V of his _Behavior_, 1914, gives a
good account of the instincts of animals.

{118}


CHAPTER VII

EMOTION

VARIOUS ORGANIC STATES, AND THE CONSCIOUS STATES THAT GO WITH THEM

Joy, sorrow, fear, anger, amusement, disgust and curiosity illustrate
the meaning of the term "emotion". An emotion is a "moved" or
stirred-up state of mind. Or, since almost any such state of mind
includes also elements that are cognitive, like recognition of present
objects or memories of the past, we might better speak of emotion as
the stirred-up-ness present in a state of mind. The emotional part of
the total state may be so strong as to overshadow all other
components, or it may have less intensity down to zero.

Such is emotion from the introspective point of view; but it can also
be observed objectively, and in fact there is more to say about it
objectively than introspectively. What appears to introspection as the
scarcely analyzable state of anger appears to the external observer as
clenched fists, flushed face, labored breathing, tense muscles, loud
voice, and many other describable details. Anger is a state of the
organism, or state of the individual, rather than simply a state of
mind.

We shall have a more comprehensive definition, then, if we substitute
"state of the individual" for "state of mind", and say that emotion is
a stirred-up state of the individual. It is a conscious state,
however; an "unconscious emotion" would be practically a contradiction
in terms. Not but that a person may be angry without knowing it. He
may be {119} "unconscious of the fact" that he is angry; which simply
means that he is not introspectively observing himself and analyzing
his mental state. But it is impossible that his organic state shall be
all stirred up and his mental state meanwhile perfectly calm and
intellectual. In short, an emotion is a conscious stirred-up state of
the organism.


Organic States That Are Not Usually Classed as Emotions

Something was said before about "organic states", under the general
head of tendencies to reaction. Fatigue was an example. Now we could
include fatigue under the term, "stirred-up state of the organism"; at
least, if not precisely "stirred-up", it is uneasy. It is a deviation
from the normal or neutral state. Also, it is often a conscious state,
as when we speak of the "tired feeling"; not a purely cognitive state,
either--not simply a recognition of the _fact_ that we are
fatigued--but a state of disinclination to work any longer. Though
fatigue is thus so much like an emotion that it fits under our
definition, it is not called an emotion, but a sensation or complex of
sensations. After hard muscular work, the state of the muscles makes
itself felt by "fatigue sensations", and the sum total of these,
coming from many different muscles, makes up the complex sensation of
fatigue. After prolonged mental work, there may be fatigue sensations
from the eyes and perhaps from the neck, which is often fixed rigidly
during strenuous mental activity; and there are perhaps other obscure
fatigue sensations originating in other organs and contributing to the
total sensation which we know as mental fatigue, or as general
fatigue.

Many other organic states are akin to emotion in the same way. The
opposite of fatigue, the "warmed-up" condition, brought on by a
certain amount of activity after {120} rest, is a case in point. It is
a deviation from the average or neutral condition, in the direction of
greater readiness for activity. The warmed-up person _feels_ ready for
business, full of "ginger" or "pep"--in short, full of life. The name
"euphoria" which means about the same as "feeling good", is given to
this condition. Drowsiness is another of these emotion-like states;
but hunger and thirst are as typical examples as any.


How These Organic States Differ from Regular Emotions

Now why do we hesitate to call hunger, fatigue and the rest by the
name of emotions? For two reasons, apparently. There are two salient
differences between an organic state such as hunger, and an emotion
such as anger.

Hunger we call a sensation because it is _localized_; we feel it in
the region of the stomach. Thirst we localize in the throat, muscular
fatigue in the fatigued muscles, and there are several other organic
states that come to us as sensations from particular organs. This is
not entirely true of drowsiness or euphoria, but it is still less true
of the emotions, which we feel as in _us_, rather than in any _part_
of us. We "feel mad all over", and we feel glad or sorry all over. It
is true that, traditionally, the heart is the seat of the emotions,
which means, no doubt, that they are felt in the region of the heart
more than elsewhere; and other ancient "seats", in the bowels or
diaphragm, agree to this extent that they point to the interior of the
trunk as the general location where the emotions are felt. But at best
the location of emotions is much less definite than that of the
sensations of fatigue or hunger.

The second difference between the emotions and the other organic
states comes to light when we notice their causes. Thirst, as an
organic state, is a lack of water resulting {121} from perspiration,
etc.; hunger as an organic state results from using up the food
previously eaten; fatigue results from prolonged muscular activity.
Each of these organic states results naturally from some internal
bodily process; while, on the contrary, the exciting cause of an
emotion is usually something _external_ which has nothing directly to
do with the internal state of the body. Here I am, perfectly calm and
normal, my organic state neutral, when some one insults me and throws
me into a state of rage; this queer state seems to be inside me,
specially in the trunk. Now how can the sound of the insulting
person's voice produce any change in my insides? Evidently, by way of
the auditory nerve, the brain and lower centers, and the motor nerves
to the interior. While, then, organic states of the hunger class
result directly from internal physiological processes, the organic
state in an emotion is aroused by the brain, the brain itself being
aroused by some stimulus, usually external.


The Organic State in Anger

But perhaps we are going too fast in assuming that there is any
peculiar internal state in emotion. Possibly our subjective
localization of anger in the trunk is all wrong, and everything there
is going on as usual. At least, the question is squarely before us
whether or not there is any internal bodily response in emotion.

Suppose we have a tame cat, that knows us well, and, after feeding her
a good meal containing some substance that is opaque to the X-rays,
suppose we place her on a table and pass X-rays through her body, so
as to get a visible shadow of the stomach upon the plate of the X-ray
machine. Well and good; the cat is contentedly digesting her meal, and
the X-ray picture shows her stomach to be making rhythmical churning
movements. In comes a fox {122} terrier and barks fiercely at the cat,
who shows the usual feline signs of anger; but she is held in position
and her stomach kept under observation--when, to our surprise, the
stomach movements abruptly cease, not to begin again till the dog has
been gone for perhaps fifteen minutes. The churning movements of the
intestine cease along with those of the stomach, and, as other
experiments show, even the gastric juice stops flowing into the
stomach. The whole business of digestion halts during the state of
anger. So anger is an organic state, without doubt. At least in
cats--but the same is found to be true of man, and hence the excellent
rule not to get angry on a full stomach.

Stomach-inhibition is not the only internal response during anger. The
heart, so long regarded as the seat of the emotions, does beat more
forcibly than usual; and the diaphragm, where the old Greeks located
the emotions, does make extra-strong breathing movements. There are
yet other and more curious changes that have recently been discovered
by the physiologists.


Glandular Responses During Emotion

Thus far, we have been considering muscular responses, but now we must
turn our attention to the glands. The glands are often affected during
emotion, as witness the shedding of tears in grief, sweating in anger,
the dry mouth during fear due to inhibition of the salivary glands,
and the stoppage of the gastric juice during anger, as just noted.
These particular glands all pour out their secretions either upon the
skin or upon the mucous membrane of the mouth, stomach, etc.; and such
secretion is called "external" in distinction from the "internal
secretion" of certain other glands which may be called the glands of
internal secretion or the "endocrine glands". Internal secretions are
{123} discharged into the blood vessels, and carried by the blood to
all parts of the body, and they have important effects on the activity
of various organs.

Of the endocrine glands, we will mention only two, which are known to
play an important part in mental life.

The thyroid gland, situated in the lower part of the neck, is
necessary for normal brain activity. Without its internal secretion,
brain activity is very sluggish.

The adrenals, two little glands located near the kidneys (whence their
name, though they have nothing to do with the kidney in function),
have a close connection with such emotions as anger. In the normal or
neutral state of the organism, the adrenal secretion oozes slowly into
the blood, and has a tonic influence on the heart and muscles. But let
an anger stimulus occur, and within a few seconds the adrenals are
secreting rapidly; all the organs soon get a big dose of the adrenal
secretion, and some of them are strongly affected by it. It hastens
and strengthens the action of the heart, it causes the large veins
inside the trunk to squeeze the blood lagging there back to the heart;
and by these two means greatly quickens the circulation. It also
affects the liver, causing it to discharge large quantities of stored
sugar into the blood. Thus the muscles of the limbs get an unusual
quantity of their favorite fuel supplied them, and also, by the
increased circulation, an unusual quantity of oxygen; and they are
enabled to work with unusual energy. The adrenal secretion also
protects them in some way against fatigue.

While the adrenal secretion is thus exerting a very stimulating
influence on the limb muscles, it is having just the opposite effect
on the digestive organs; in fact it is having the effects described
above as occurring there during anger. These inhibitory effects are
started by the stomach nerves, but are continued by the action of the
adrenal juice {124} on the stomach walls. The rapid secretion of the
adrenal glands during anger is itself aroused by the nerve running to
this gland.


The Nerves Concerned in Internal Emotional Response

There is a part of the nervous system called the "autonomic system",
so called because the organs it supplies--heart, blood vessels,
stomach, intestines and other internal organs, possess a large degree
of "autonomy" or independence. The heart, it will be remembered, beats
of itself, even when cut off altogether from any influence of the
nerve centers; and the same is true in some measure of the other
internal organs. Yet they are subject to the influence of the nerve
centers, which reinforce and inhibit their activity. Each internal
organ has a double supply of nerves, one nerve acting to reinforce the
activity of the organ and the other to inhibit it; and both the
reinforcing and the inhibiting nerves belong to the autonomic system.

The autonomic is not separate from the main nervous system, but
consists of outgoing axons from centers in the cord and "medulla"
(part of the brain stem). It has three divisions, one from the
medulla, one from the middle reach of the cord, and one from the lower
part of the cord; and these three divisions are related to three
different emotional states. The upper division, from the medulla,
favors digestion by promoting the flow of gastric juice and the
churning movements of the stomach; and at the same time it seems to
favor the comfortable, rather lazy state that is appropriate for
digestion. The middle division (often called the "sympathetic", though
the name is rather misleading to a student of psychology, as it has
nothing to do with "sympathy") checks digestion, hastens the heart
beat, and stimulates the adrenal glands to rapid secretion, thus
giving {125} rise to the organic condition of anger. The lower
division has to do with the bladder, rectum and sex organs, and is
active during sex excitement, for one thing.

The lower centers in the medulla and cord that give rise to the
autonomic nerves are themselves much under the influence of the
higher, cerebral centers. Thus appetite for food, and the flow of
gastric juice, can be aroused by the sight of good food, or by hearing
or reading about food, or even by merely thinking of food; and both
anger and sex appetite can be aroused in corresponding ways.

We should notice right here the antagonism that exists between the
middle division of the autonomic and the other two. Suppose the upper
division is active, as in comfortable digestion, when an angering
stimulus supervenes; then, as we have seen, digestion halts, the upper
autonomic is shunted out of action by the middle division. In the same
way, sex appetite is shunted out by anger.


The Emotional State as a Preparatory Reaction

An emotion is often spoken of as a disturbance of the normal quiet
state, and as if it represented a breakdown of the organism's
machinery. Anger or fear is often a nuisance in civilized life, and
any strong emotion is apt to disturb mental work or skilled manual
work. But if we think ourselves back into a primitive condition of
life, when anger means a fight, we see that the organic response in
anger makes a first-class preparation for the fight. Rapid
circulation, abundant muscular fuel, protection from fatigue--these
are all positively useful; and the halting of digestion is useful also
in relieving the circulation from taking care of an activity that can
afford to wait.

What we have been calling the "organic state in anger" occurs also in
_fear_ of the strong type (as distinguished from {126} fear
paralysis), and in certain other states that are not exactly either
fear or anger, such as the state of a football player before the game,
or the state of a student about to take an examination. It is the
state of _excitement_ or of being "all keyed up". So far as known, the
organic response (including the adrenal secretion) is the same in
these various instances of excitement: anger, fear, zeal and so on.
When an individual is in this organic state, his muscles will work
harder and longer than is otherwise possible; and thus are explained
those remarkable cases of extraordinary strength and endurance in
great emergencies, as in escaping from a fire or from a bombarded
city.

The fear-anger state of the organism, being certainly a state of
preparedness for attack or defense, suggests the following
generalization: "Any emotion represents internal preparation for some
type of overt action." This holds good, at least, for food appetite
and sex appetite. Regarding the other emotions, we know too little of
the internal responses that may occur, to judge whether or not they
have any utility as preparatory reactions.


"Expressive Movements," Another Sort of Preparatory Reactions

Though we know little of any internal response in many of the
emotions, we almost always find some characteristic external movement,
such as smiling, scowling, pouting, sneering, sobbing, screaming,
shouting or dancing. By aid of such "expressive movements" we are
sometimes able to judge the emotional state of another person. But
what is the sense of these movements? At first thought, the question
itself is senseless, the movements are so much a matter of course,
while on second thought they certainly do seem odd. What sense is
there is protruding the lips when sulky, {127} or in drawing up the
corners of the mouth and showing the canine teeth in contempt? Perhaps
they are just odd tricks of instinct--for we agreed in the preceding
chapter not to assume all instinctive responses to be useful. Darwin,
however, after studying a great many of these expressive movements,
both in men and in animals, reached the conclusion that, if not of
present utility, they were survivals of acts that had been useful
earlier in the life of the individual or of the race.

Shaking the head from side to side, in negation or unwillingness,
dates back to the nursing period of the individual's life, when this
movement was made in rejecting undesired food. Directly useful in this
case, it was carried over to analogous situations that aroused the
child's reluctance.

Showing the teeth in scorn dates back, according to Darwin, to a
prehuman stage of development, and is seen in its useful form in
animals like the dog or gorilla that have large canine teeth. Baring
the teeth in these animals is a preparation for using the teeth; and
often, also, it frightens the enemy away and saves the bother of
actually attacking "small fry". The movement, Darwin urges, has
survived in the race, even after fighting with the teeth has largely
disappeared.

Many other expressive movements are traced back in a similar way,
though it must be admitted that the racial survivals are usually less
convincing than those from the infancy of the individual. The nasal
expression in disgust was originally a defensive movement against bad
odors; and the set lips of determination went primarily with the set
glottis and rigid chest that are useful in lifting heavy weights or in
other severe muscular efforts. Such movements, directly useful in
certain simple situations, become linked up with analogous situations
in the course of the {128} individual's experience. Many of them,
certainly, we can regard as preparatory reactions.


Do Sensations of These Various Preparatory Reactions
Constitute the Conscious State of Emotion?

No one can doubt that some of the bodily changes that occur during an
emotion make themselves felt as sensations. Try this experiment:
pretend to be angry--it is not hard!--go through the motions of being
angry, and notice what sensations you get. Some from the clenched
fist, no doubt; some from the contorted face; some from the neck,
which is stiff and quivering. In genuine anger, you could sense also
the disturbed breathing, violent heart beat, hot face. The internal
responses of the adrenal glands and liver you could not expect to
sense directly; but the resulting readiness of the limb muscles for
extreme activity is sometimes sensed as a feeling of tremendous
muscular power.

Now lump together all these sensations of bodily changes, and ask
yourself whether this mass of sensations is not identical with the
angry state of mind. Think all these sensations away, and ask yourself
whether any angry feeling remains. What else, if anything, can you
detect in the conscious emotional state besides these blended
sensations produced by internal and external muscular and glandular
responses?

If you conclude that the conscious emotion consists wholly of these
sensations, then you are an adherent of the famous James-Lange theory
of the emotions; if you find any other component present in the
emotion, you will find this theory unacceptable.

{129}

The James-Lange Theory of the Emotions

The American psychologist James, and the Danish psychologist Lange,
independently of each other, put forward this theory in the early
eighties of the last century, and it has ever since remained a great
topic for discussion. According to the theory, the emotion is the _way
the body feels_ while executing the various internal and expressive
movements that occur on such occasions. The "stirred-up state of mind"
is the complex sensation of the stirred-up state of the body. Just as
fatigue or hunger is a complex of bodily sensations, so is anger, fear
or grief, according to the theory.

James says, we do not tremble because we are afraid, but are afraid
because we tremble. By that he means that the conscious state of being
afraid is composed of the sensations of trembling (along with the
sensations of other muscular and glandular responses). He means that
the mental state of recognizing the presence of danger is not the
stirred-up state of fear, until it has produced the trembling and
other similar responses and got back the sensations of them. "Without
the bodily states following on the perception"--i.e., perception of
the external fact that arouses the whole emotional reaction--"the
latter would be purely cognitive in form, pale, colorless, destitute
of emotional warmth. We might then see the bear, and judge it best to
run, receive the insult, and deem it right to strike, but we should
not actually _feel_ afraid or angry."

It has proved very difficult to submit this theory to a satisfactory
test. The only real test would be to cut off sensations from the
interior of the trunk entirely; in which case, if the theory is right,
the conscious emotion should fail to appear, or at least lack much of
its "emotional warmth". Evidence of this sort has been slow in coming
in. One or {130} two persons have turned up at nerve clinics,
complaining that they no longer had any emotions, and were found to
have lost internal bodily sensation. These cases strongly support the
theory, but others have tended in the opposite direction. The fact
that the internal response is the same in anger, and in fear of the
energetic type, shows that the difference between these emotions must
be sought elsewhere. Possibly sufficient difference could be found in
the expressive movements, or in minor internal responses not yet
discovered. If not, the theory would certainly seem to have broken
down at this point.

In any case, there is no denying the service done by the James-Lange
theory in calling attention to bodily sensations as real components of
the conscious emotional state.


Emotion and Impulse

Most people are rather impatient with the James-Lange theory, finding
it wholly unsatisfactory, though unable to locate the trouble
precisely. They know the theory does not ring true to them, that is
all. Now the trouble lies just here: what they mean by "being afraid"
is "wanting to get away from the danger", what they mean by "being
angry" is "wanting to strike the offending person", and in general
what they mean by any of the named "emotions" is not a particular sort
of "stirred-up conscious state", but an _impulse_ towards a certain
action or a certain result. Evidently it would be absurd to say we
want to get away from the bear because we tremble, or that until we
started to tremble we should be perfectly indifferent whether the bear
got us or not.

The tendency to escape is aroused directly by the perception of
danger; of that there can be no doubt. It does not depend on
trembling, but for that matter neither does it depend on _feeling_
afraid. Sometimes we recoil from a {131} sudden danger before
experiencing any thrill of fear, and are frightened and tremble the
next moment, after we have escaped. The stirred-up state develops more
slowly than the tendency to escape. The seen danger directly arouses
an adjustment towards the end-result of escape, and both the
preparatory bodily responses and the feeling of fear develop after
this adjustment has been set up. If the end-result is reached
instantly, the preparatory reactions and the feeling may not develop
at all, or they may put in an appearance after the main act is all
over. There is nothing in all this that speaks either for or against
the James-Lange theory.

These statements need further elucidation, however. Notice, first,
that psychology makes a perfectly proper and important distinction
between emotion and impulse. In terms of consciousness, emotion is
"feeling somehow", and impulse is "wanting to do something". In
behavior terms, emotion is an organic state, and impulse an adjustment
of the nerve centers towards a certain reaction. An impulse is a
conscious tendency.

Since emotion and impulse so often go together, common sense does not
bother to distinguish them, and the common names for the "emotions"
are more properly names of impulses. Fear means the impulse to escape,
rather than any specific stirred-up state. Psychology has, indeed,
made a mistake in taking over these names from common speech and
trying to use them as names of specific emotional states. We were
having some difficulty, a few moments ago, in finding any great
distinction between fear and anger, considered as emotional
states--just because we were overlooking the obvious fact that "fear"
is an impulse to escape from something, while "anger" is an impulse to
get at something and attack it. The adjustments are very different,
but the organic states are much alike.

{132}

The organic state in fear or anger cannot generate the escape or
fighting tendency, since the two tendencies are so different in spite
of the likeness of the organic state. The tendencies are aroused
directly by the perception of the dangerous or offensive object. The
order of events is as follows. The stimulus that sets the whole
process going is, let us say, a bear in the woods. First response:
seeing the bear. Second response: recognizing the dangerous situation.
Third response: adjustment towards escape. Fourth response (unless
escape is immediate): internal preparatory reactions, adrenal, etc.;
also, probably, external expressive movements and movements steered in
the general direction of escape. Fifth response: conscious stirred-up
state consisting of blended sensations of all these preparatory
reactions. Sixth response (by good luck): definitive escape reaction.
Seventh response: satisfaction and quiescence.


[Illustration: Fig. 24.--Here the stimulus-response diagram is
complicated to take account of the emotional state. The ellipse here
stands for the brain. S arouses T, a tendency towards the response R.
But T also arouses P, a bodily state of preparedness, and sensations
(E) of this bodily state, together with T, constitute the conscious
state of the individual while he is tending towards the response, or
end-result, R.]


Emotion Sometimes Generates Impulse

Typically, impulse generates emotion. The reaction tendency is primary
and the emotion secondary.

But suppose the organic state of fear to be {133} present--never mind
how it got there--might it not act like hunger or fatigue, and
generate a fear impulse? Could it not be that a person should first be
fearful, without knowing what he was afraid of and without really
having anything to be afraid of; and then, as it were, _find_
something to be afraid of, something to justify his frightened state?
This may be the way in which abnormal fears sometimes arise: a
naturally timid individual is thrown by some obscure stimulus into the
state of fear, and then attaches this fear to anything that suggests
itself, and so comes to be afraid of something that is really not very
terrific, such as the number two, "I mustn't do anything twice, that
would be dangerous; if I do happen to do it twice, I have to do it
once more to avoid the danger; and for fear of inadvertently stopping
with twice, it is best always to do everything three times and be
safe." That is the report of a naturally timorous young man. We all
know the somewhat similar experience of being "nervous" or "jumpy"
after escaping from some danger; the organic fear state, once aroused,
stays awhile, and predisposes us to make avoiding reactions. In the
same way, let a man be "all riled up" by something that has happened
at the office, and he is likely to take it out on his wife or
children. Slightly irritating performances of the children, that would
usually not arouse an angry reaction, do so this evening, because that
thing at the office has "made him so cross."

In the same way, let a group of people get into a very mirthful state
from hearing a string of good jokes, and a hearty laugh may be aroused
by a feeble effort that at other times would have fallen flat.

In such cases, the organic state, once set up in response to a certain
stimulus, persists after the reaction to that stimulus is finished and
predisposes the individual to make the same sort of reaction to other
stimuli.

{134}

Emotion and Instinct

Anger, fear, lust, the comfortable state appropriate to digestion,
grief (the state of the weeping child), mirth or amusement, disgust,
curiosity, the "tender emotion" (felt most strongly by a mother
towards her baby), and probably a few others, are "primary emotions".
They occur, that is to say, by virtue of the native constitution, and
do not have to be learned or acquired through experience. They are
native states of mind; or, as modes of behavior, they are like
instincts in being native behavior.

One distinction between emotional and instinctive behavior is that the
emotion consists of internal responses, while the instinct is directed
outwards or at least involves action on external objects. Another
distinction is that the emotional response is something in the nature
of a preparatory reaction, while the instinct is directed towards the
end-reaction.

The close connection of emotion and instinct is fully as important to
notice as the distinction between them. Several of the primary
emotions are attached to specific instincts: thus, the emotion of fear
goes with the instinct to escape from danger, the emotion of anger
goes with the fighting instinct, the emotion of lust with the mating
instinct, tender emotion with the maternal instinct, curiosity with
the exploring instinct. Where we find emotion, we find also a tendency
to action that leads to some end-result.

It has been suggested, accordingly, that each primary emotion is
simply the "affective" phase of an instinct, and that every instinct
has its own peculiar emotion. This is a very attractive idea, but up
to the present it has not been worked out very satisfactorily. Some
instincts, such as that for walking, seem to have no specific emotion
attached to them. Others, like anger and fear, resemble each other
very {135} closely as organic states, though differing as impulses.
The really distinct emotions (not impulses) are much fewer than the
instincts.

The most important relationship between instinct and emotion is what
we have seen in the cases of anger and a few others, where the emotion
represents bodily readiness for the instinctive action.


The Higher Emotions

We have been confining our attention in this chapter to the primary
emotions. The probability is that the higher emotions, esthetic,
social, religious, are derived from the primary in the course of the
individual's experience.

Primary emotions become refined, first by modifications of the motor
response, by which socially acceptable reactions are substituted for
the primitive crying, screaming, biting and scratching, guffawing,
dancing up and down in excitement, etc.; second by new attachments on
the side of the stimulus, such that the emotion is no longer called
out by the original simple type of situation (it takes a more serious
danger, a subtler bit of humor, to arouse the emotional response); and
third by combination of one emotion with another. An example of
compound emotion is the blend of tenderness and amusement awakened in
the friendly adult by the actions of a little child. Hate is perhaps a
compound of anger and fear, and pity a compound of grief and
tenderness. There are dozens of names of emotions in the
language--resentment, reverence, gratitude, disappointment,
etc.--which probably stand for compound emotions rather than for
primary emotions, but the derivation of each one of them from the
primary emotions is a difficult task. The emotional life cannot be
kept apart from the life of ideas, for the individual is a good deal
of a unit.

{136}

EXERCISES

1. Outline the chapter.

2. Make a list of 20 words denoting various emotional states.

3. Trace the expressive facial movement of pouting back to its
   probable origin in the history of the individual.

4. What internal nerves are concerned with digestion? With fear?

5. Show by diagrams the differences between (a) the common-sense
   theory of the emotions, (b) the James-Lange theory, (c) the
   James-Lange theory modified to take full account of the
   reaction-tendency.

6. Make a list of objections to the James-Lange theory, and
   scrutinize each objection carefully, to see

   (a) whether it really attacks the theory, or misconceives it.

   (b) whether it carries much or little weight.

7. Act out several emotions, (a) by facial expression alone, and
   (b) by facial expression plus gestures, and let another person
   guess what emotion you are trying to express. How many times does
   he guess right under (a), and under (b)?

8. Discuss the relative practical importance of emotion and impulse.


REFERENCES

For the James-Lange theory, see the chapter on the emotions by William
James, in his _Principles of Psychology_, 1890, Vol. II, pp. 442-485.

For Darwin's views on expressive movements, see his _Expression of the
Emotions in Man and Animals_, first published in 1872.

For pictures of facial expression in various emotions, see Antoinette
Feleky, in the _Psychological Review_ for 1914, Vol. 21, pp. 33-41.

For the internal physiological changes, see Walter B. Cannon's _Bodily
Changes in Pain, Hunger, Fear and Rage_, 1915.

For an interesting and important view of the close connection between
emotion and instinct, see William McDougall's _Introduction to Social
Psychology_, Chapter II.

{137}


CHAPTER VIII

INVENTORY OF HUMAN INSTINCTS AND PRIMARY EMOTIONS

A LIST OF THE NATIVE STOCK OF TENDENCIES AND OF
THE EMOTIONS THAT SOMETIMES GO WITH THEM.

It would be a great mistake to suppose that instinct was important
only in animal or child psychology, because the human adult governed
his conduct entirely by reason and calculation of consequences. Man
does not outgrow instinct, any more than he outgrows emotion. He does
not outgrow the native reaction-tendencies. These primitive motives
remain in force, modified and combined in various ways, but not
eliminated nor even relegated to an unimportant place. Even in his
most intelligent actions, the adult is animated by motives that are
either plain instincts or else derivatives of the instincts. According
to some of the leaders in psychology, he has no other motives than
these; according to this book, as will be set forth later, there are
"native likes and dislikes" (for color, tone, number, persons, etc.)
to be placed beside the instincts as primary motives; but, according
to either view, the instincts are extraordinarily important in the
study of motivation, and a complete and accurate list of them is very
much to be desired. Life is a great masquerade of the instincts, and
it is not only entertaining to unmask them, but illuminating as well.

A complete account of an instinct would cover the following points:
the stimulus that naturally arouses it, the end-result at which it is
aimed, the preparatory reactions that occur, external and internal;
and also, from the {138} introspective side, the conscious impulse,
the peculiar emotional state (if any), and the special sort of
satisfaction that comes when the end-result is reached. Further, we
should know what modifications or disguises the instinct takes on in
the course of experience--what new stimuli acquire the power of
arousing it, what learned reactions are substituted for the native
preparatory and final reactions, and what combinations occur between
the instinct in question and other reaction-tendencies.

Besides all this, it would be very desirable to present convincing
evidence that each instinct listed is a genuine instinct, a part of
the native equipment, and not something built up by experience and
training. It is rather absurd, the free and easy way in which an
instinct is often assumed, simply to fit behavior which needs to be
explained--a money getting instinct, for example, or a teacher-hating
instinct. Since money and teachers do not exist in a state of nature,
there can be no instincts specifically related to them; and it is
incumbent on the psychologist to show how such acquired tendencies are
derived from the native tendencies.

The full program outlined above being much too extensive to follow out
completely in this chapter, we shall only mention a few salient points
under each instinct. We shall try to point out the primitive behavior
of the child, that reveals the instinct at its lowest terms, and give
some hint also of its importance in adult behavior.


Classification

Of all the instincts, two groups or classes stand out from the rest:
the responses to organic needs, and the responses to other persons.
The first class includes eating, avoiding injury, and many others; the
second class includes the herd instinct, the mating instinct and the
parental instinct, these three and perhaps no others.

{139}

These two groups out, the rest are rather a miscellaneous collection,
including the "random" or playful activity of young children,
locomotion, vocalization, laughter, curiosity, rivalry and fighting.
They might be named the "non-specific instincts", because the stimulus
for each is not easy to specify, being sometimes another person, so
that this group has great social importance, but sometimes being
impersonal. This third class might also be called the "play
instincts", since they are less essential than the other classes for
maintaining the individual life or for propagating the species; and
are, we may say, less concerned with the struggle for existence than
with the joy of living.

Our classification then has three heads:

  (1) Responses to organic needs,
  (2) Responses to other persons,
  (3) Play responses.


Responses to Organic Needs

Something has already been said [Footnote: See above, pp. 79-81, 112.]
of the manner in which an organic state, such as lack of water, acting
on internal sensory nerves, arouses in the nerve centers an adjustment
towards an end-result, and how, if the end-result cannot immediately
be attained, preparatory reactions occur, the preparatory reactions
being in some cases closely attached, by nature, to the main tendency,
and in other cases only loosely attached so that the tendency leads to
trial and error behavior. The reactions that are nearest to the
end-result are likely to be closely attached to the main tendency,
while those that are farther from the end-result are loosely attached.
Thus, in the case of _thirst_, the drinking movement itself is about
all, in man, that is purely instinctive, {140} and the way of getting
water to the mouth, or the mouth to the water, is a matter for trial
and error, and only becomes fixed as the result of a process of
learning. Still less can we mention any specific water-seeking
reactions, in the human being, that are provided by the native
constitution. Yet the whole business of relieving thirst is directed
by the native thirst-impulse, and to that extent is an instinctive
activity. And shall we say that so simple a matter as meeting this
organic need is below the dignity of psychology, and can have little
influence on the behavior of mankind? Hardly, when we think of the
role played by springs, wells and drinking places of all kinds in the
life of the race, of aqueducts and reservoirs, of all the beverages
that have been invented, and of all the people whose job it has been
to provide and dispense them. To be sure, any beverage with a taste,
or a "kick", is not simply a thirst-reliever, but makes some
additional appeal, good or bad; but all this simply illustrates the
way instincts become modified, by combination with other instincts,
and by the learning and fixing of various preparatory reactions that
were not provided, ready-made, in the native constitution. The
drinking instinct, or thirst impulse, is a very good example of this
whole class of organic instincts.


Instincts connected with hunger.

Here again, the reactions nearest to the end-result (food in the
stomach) are provided by nature. Sucking and swallowing appear at
birth, chewing with the appearance of the teeth; and the infant also
makes what seem to be instinctive movements of seeking the breast, as
well as movements of rejecting it when satiated and of spitting out
bad-tasting food. Putting food (and other things) into the mouth by
the hands seems almost instinctive, and yet it has to be fixed by
trial and error. Anything like definite food-seeking behavior,
amounting to a _hunting_ instinct, scarcely gets a chance to show
itself in {141} the human child, because his food is provided for him.
In many animals, hunting is a highly organized instinct; thus,
crouching, stalking, springing and teasing the mouse when caught, have
been proved to be instinctive in young cats. Some animals have
definite food-storing instincts also, and possibly food-storing shows
the acquisitive or collecting tendency in its lowest terms. Possibly,
that is to say, hunting and collecting, as well as disgust (primarily
of bad-tasting or bad-smelling food), are originally parts of the
food-getting behavior, having the general character of reactions
preparatory to eating. However this may be, we can easily see the
great importance of the hunger motive in human life; we have only to
consider the matter in the same way as we considered thirst just
above.

Breathing and air-getting.

Breathing, obviously a native reaction, is ordinarily automatic and
needs no preparatory reactions, simply because air is so easy to get.
But let breathing be difficult, for any reason, and the stifling
sensation is as impulsive as hunger or thirst. The stuffy air in a
cave or in a hole under a haymow will lead a child to frantic escape.
Possibly the delight in being out of doors which shows itself in young
children, and is not lost in adults, represents a sort of air-hunting
instinct, parallel to food-hunting. Closely connected with breathing
is the function of circulation, automatic for the most part; and we
should mention also the organic needs of waste-elimination, which give
impulsive sensations akin to hunger and thirst, and lead to more or
less organized instinctive reactions.


Responses to heat and cold.

The warm-blooded animals, birds and mammals, have the remarkable power
of keeping the body temperature constant (at 98-99 degrees Fahrenheit,
in man, somewhat higher in birds), in spite of great variations in the
external temperature to which the body is exposed, and in spite of
great variations in the {142} amount of heat generated in the body by
muscular exercise. Sweating and flushing of the skin are reactions to
heat, and prevent the body temperature from rising; paling of the
skin, shivering and general muscular activity are responses to cold
and prevent the body temperature from falling. Shrinking from great
heat or cold are also instinctive, while seeking shelter from the heat
or cold is a preparatory reaction that is not definitely organized in
the native constitution of man, but gives rise to a great variety of
learned reactions, and plays a considerable part in life.


Shrinking from injury.

The "flexion reflex" of the arm or leg, which pulls it away from a
pinch, prick or burn, is the type of a host of defensive
reactions--winking, scratching, rubbing the skin, coughing, sneezing,
clearing the throat, wincing, limping, squirming, changing from an
uncomfortable position--most or all of them instinctive reactions.
With each goes some sort of irritating sensation, as pain, itching,
tickling, discomfort; and a conscious impulse to get rid of the
irritation is often present. When the simpler avoiding reactions do
not remove the irritating stimulus, they are repeated more vigorously
or give way to some bigger reaction tending towards the same result.
The climax of the avoiding reactions is flight or running away. Akin
to flight are cowering, shrinking, dodging or warding off a blow,
huddling into the smallest possible space, getting under cover,
clinging to another person; and most or all of these, too, are
instinctive reactions. With flight and the other larger
danger-avoiding reactions there is often present, along with the
impulse to escape, the stirred up organic and conscious state of
_fear_.

The stimuli that arouse movements of escape are of two sorts: those
that directly cause some irritating sensation, and those that are
simply signs of danger. The smaller avoiding reactions--flexion
reflex, coughing, etc.--are {143} aroused by stimuli that are directly
painful or irritating; whereas flight, cowering, etc., are mostly
responses to mere signs of danger. A "sign of danger" is usually seen
or heard at some distance, not felt directly on or in the body. Now,
while avoiding reactions are attached by nature to the irritating
stimuli, it is not at all clear whether escape movements are
_natively_ attached to any signs of danger, or, if they are, to what
particular signs of danger they are attached. What visual or auditory
stimuli, that are not directly irritating, will arouse escape
movements in a young child? For the youngest children, no such stimuli
have been found. You can easily get avoiding reactions from a little
baby by producing pain or discomfort; you can get the clinging
response by letting the child slip when he is being held in your arms;
and you get crying and shrinking on application of a loud, grating
noise, such a noise as is irritating in itself without regard to what
it may signify. But you cannot get any shrinking from stimuli that are
not directly irritating.

For example, you get no sign of fear from a little child on suddenly
confronting him with a furry animal. With older children, you do get
shrinking from animals, but it is impossible to be sure that the older
child has not _learned_ to be afraid of them. I have seen a child of
two years simply laugh when a large, strange dog came bounding towards
him in the park; but a year later he would shrink from a strange dog.
Whence the change? There are two possibilities: either a native
connection between this stimulus and the shrinking response only
reached its maturity when the child was about three years old--and
there is nothing improbable in this--or else the child, though
actually never bitten by a dog, had been warned against dogs by his
elders or had observed his elders shrinking from dogs. Children do
pick up fears in this way; for example, children who are {144}
naturally not the least bit afraid of thunder and lightning may
acquire a fear of them from adults who show fear during a
thunderstorm.

On the whole, the danger-avoiding reactions are probably not linked by
nature to any special signs of danger. While the emotion of fear, the
escape impulse, and many of the escape movements are native, the
attachment of these responses to specific stimuli--aside from directly
irritating stimuli--is acquired. Fear we do not learn, but we learn
what to fear.


Crying.

We have the best of evidence that this is a native reaction, since the
baby cries from birth on. He cries from hunger, from cold, from
discomfort, from pain, and, perhaps most of all, as he gets a little
older, from being thwarted in anything he has set out to do. This last
stimulus gives the "cry of anger", which baby specialists tell us
sounds differently from the cries of pain and of hunger. Still, there
is so much in common to the different ways of crying that we may
reasonably suppose there is some impulse, and perhaps some emotional
state, common to all of them. The common emotion cannot be anger, or
hunger, or discomfort or pain. To name it grief or sorrow would fit
the crying of adults better than that of little children. The best
guess is that the emotional state in crying is the feeling of
_helplessness_. The cry of anger is the cry of helpless anger; anger
that is not helpless expresses itself in some other way than crying;
and the same is true of hunger, pain and discomfort. Crying is the
reaction appropriate to a condition where the individual cannot help
himself--where he wants something but is powerless to get it. The
helpless baby sets up a wail that brings some one to his assistance;
that is the utility of crying, though the baby, at first, does not
have this result in view, but simply cries because he is hungry and
helpless, uncomfortable and {145} helpless, thwarted and helpless. The
child cries less as he grows older, because he learns more and more to
help himself.

With the vocal element of crying goes movement of the arms and legs,
which also has utility in attracting attention; but what may be the
utility of shedding copious tears remains a mystery, in spite of
several ingenious hypotheses that have been advanced to explain it.


Fatigue, rest and sleep.

That fatigue, primarily an organic state, gives rise to fatigue
sensations and to a neural adjustment for rest--a disinclination to
work any longer--and that drowsiness is a somewhat different organic
state that gives an inclination to sleep--all this has been
sufficiently set forth in earlier chapters. Going to sleep is a
definite act, an instinctive response to the drowsy state. In the way
of preparatory reactions, we find many interesting performances in
birds and mammals, such as the curling up of the dog or cat to sleep,
the roosting of hens, the standing on one leg of some birds; and we
see characteristic positions adopted by human beings, but do not know
how far these are instinctive and how far acquired. Closing the eyes
is undoubtedly a native preparatory reaction for sleep.

Like the other responses to organic needs, rest and sleep figure
pretty largely in the behavior of the adult, as in finding or
providing a good place to sleep. Certainly if fatigue and sleep could
be eliminated, as some over-enthusiastic workers have pretended to
hope, life would be radically changed.


Instinctive Responses to Other Persons

We are next to look for action and emotion aroused by persons,
specifically--not by persons and things alike. Fear can be aroused by
persons, but also by things. In a social animal, such as man, almost
any instinct comes to have {146} social bearings. Eating and drinking
become social matters, and all the organic instincts figure in the
placing and making of a home. Home is a place of shelter against heat
and cold, it is a refuge from danger, it is where you eat and where
you sleep. It meets all these organic needs but--it is specially where
"your people" are.

Home is a place where _unlike_ persons foregather, male with female,
adults with children, and thus it symbolizes the "family instincts",
mating and child-care, which are responses to persons unlike in sex or
age. But home also illustrates very well the herd instinct, which is a
response to like persons, "birds of a feather flocking together". It
is not the single home that illustrates this, but the almost universal
grouping of homes into villages or cities.


The herd instinct or gregarious instinct.

It might be argued that a city or village was the result of economic
causes, or, in the olden days, a means of protection against enemies,
and not a direct satisfaction of any instinct in man to flock
together. But often a family who know perfectly well that their
economic advantage demands their remaining where they are, in some
isolated country spot, will pull up stakes and accept an inferior
economic status in the city, just because the country is too lonely
for them. One woman, typical of a great many, declined to work in a
comfortable and beautiful place in the country, because "she didn't
want to see trees and rocks, she wanted to see people". There is no
doubt that man belongs by nature with the deer or wolf rather than
with solitary animals such as the lion. He is a gregarious creature.

The gregarious instinct does not by any manner of means account for
all of man's social behavior. It brings men together and so gives a
chance for social doings, but these doings are learned, not provided
ready-made by the instinct. About all we can lay to the herd instinct
is uneasiness when {147} alone, seeking company, remaining in company,
and following the rest as they move from place to place. The feeling
of loneliness or lonesomeness goes with being alone, and a feeling of
satisfaction goes with being in company.

Probably there is one more fact that belongs under the herd instinct.
A child is lonely even in company, unless he is allowed to
_participate_ in what the others are doing. Sometimes you see an adult
who is gregarious but not sociable, who insists on living in the city
and wishes to see the people, but has little desire to talk to any one
or to take part in any social activities; but he is the exception. As
a rule, people wish not only to be together but to do something
together. So much as this may be ascribed to the instinct, but no
more. "Let's get together and _do something_"--that is as far as the
gregarious instinct goes. _What_ we shall do depends on other motives,
and on learning as well as instinct.


The mating instinct.

Attraction towards the opposite sex is felt by a small number of
children, by most young people beginning from 15 to 20 years of age,
by a minority not till a few years later, and, by a small number,
never at all. On account of the late maturing of this instinct, in
man, instinctive behavior is here inextricably interwoven with what
has been learned. A definite organic and emotional state, lust, goes
with this instinct. Preparatory reactions, called "courtship", are
very definitely organized in many animals, and often quite elaborate.
In man, courtship is elaborate enough, but not definitely organized as
an instinct; and yet it follows much the same line as we observe in
animal courtship. It begins with admiring attention to one of the
opposite sex, followed by efforts to attract that one's attention by
"display" (strutting, decoration of the person, demonstrating one's
prowess, especially in opposition to rivals). Then the male takes an
aggressive attitude, the {148} female a coy attitude; the male woos,
the female hangs back, and something analogous to pursuit and capture
takes place, except that the capture may be heartily accepted by both
parties.

The "survival value" of this instinct is absolute; without it the race
would not long survive. But it has "play value" also, it contributes
to the joy of living as well as to the struggle for survival. There is
much in social intercourse, and in literature and art, that is
motivated by the sex impulse. Some would-be psychologists have been so
much impressed by the wide ramifications of the sex motive in human
conduct that they have attributed to it all play, all enjoyment, all
the softer and lighter side of life, even all the spiritual side of
life. One need only run over the long list of instincts, especially
those that still remain to be mentioned, in order to be convinced of
the one-sidedness of such a view. On the other hand, some moralists
have been so deeply impressed by the difficulties that arise out of
the sex motive, as to consider it essentially gross and bad; but this
is as false as the other view. The sex impulse is like a strong but
skittish horse that is capable of doing excellent work but requires a
strong hand at the reins and a clear head behind. It is a horse that
does not always pull well in a team; yet it is capable of fine
teamwork. It can be harnessed up with other tendencies, and when so
combined contribute some of its motive force to quite a variety of
human activities.


The parental or mothering instinct.

In many species of animals, though not by any means in all, one or
both of the parents stays by the young till some degree of maturity is
reached. In some kinds of fish, it is the male that cares for the
young; in birds it is often both parents. In mammals it is always the
mother. Instinctively, the mammalian mother feeds, warms and defends
her young. Just as {149} instinctively, the human mother does the
same. This instinctive reaction to the little baby is attended by a
strong emotion, called, for want of a better name, the "tender
emotion".

The strongest stimulus to arouse this instinct is the little, helpless
baby. The older child has to take second place with the mother, so
soon as there is a little baby there. After a child is weaned, and
after he is able to get about and do for himself to quite an extent,
he has less hold on the maternal instinct. The love and care that he
may still get is less a simple matter of instinct.

Though the little baby is the strongest stimulus to this instinct,
older children and even adults, provided they are like the baby in
being winsome and helpless in some way, may arouse the same sort of
feeling and behavior, tender feeling and protective behavior. A pet
animal may arouse the same tendency, and a "darling little calf" or a
"cute little baby elephant" may awaken something of the same thrill.
Even a young plant may be tended with a devotion akin to the maternal.
The fact seems to be here, as with other instincts, that objects
similar to the natural stimulus may arouse the same impulse and
emotion. Love between the sexes is often a compound of sex attraction
and the mothering instinct; and it is interesting to watch a happily
mated couple each mothering the other.

But is it allowable to speak of this instinct as present in the male
human being, or in any one not a mother? Undoubtedly the woman who has
recently become a mother is most susceptible to the appeal of a little
baby, but the response of other women and of girls to a baby is so
spontaneous that we cannot but call it instinctive. Men and boys have
no special desire to feed or cuddle a little baby, and are quite
contented to leave the care of the baby mostly to the "women folks".
But they do object strongly to seeing the {150} baby hurt or
ill-treated, and will respond by protecting it. Also, they like to
watch the baby act, and like to help it along in its efforts to do
things. This may be instinctive in the man; at least it reminds us of
the behavior of a mother cat or dog or horse, when she plays with her
young and stimulates them to action. When the mother cat brings a live
mouse for her half-grown kittens to practise on, she is acting
instinctively, and probably a man is obeying the same instinct when he
brings the baby a toy and derives pleasure from watching the baby's
attempts to use it.

The parental instinct would thus seem to lie at the root of education,
considered as an enterprise of adults directed towards getting the
young to acquire the behavior of the race; and it also lies at the
root of charity, the desire to protect the helpless.

Is there any instinct in the child answering to the parental, any
"filial" instinct, as it were? Psychologists have usually answered no,
but possibly they have been misled by the word "filial" and looked in
the wrong direction. The parental instinct is an instinct to give, and
the answering instinct would be one to take--not to give in return. It
is probably not instinctive for the child to do for the parent, but is
it not instinctive for the child to take from the parent, and to look
to the parent for what he wants? It is not exactly "unnatural conduct"
in a child to impose on his mother, as it would be in the mother to
impose on the child; but would it not be unnatural in a child to take
an unreceptive and distrustful attitude towards his mother?

Filial love is different. It is not purely instinctive, but depends on
intelligence. It is only possible if the child has the intelligence to
see the parent as something besides a parent--as some one needing care
and protection--and if the child himself takes a parental attitude
towards the parent. But that is a grown-up attitude, seldom taken by
{151} young children. It is not the infantile instinct, which, if
there is such an instinct, is the spring of trustful, docile,
dependent, childlike and childish behavior.


The Play Instincts

Any instinct has "play value", but some have also "survival value" and
so are serious affairs. Survival value characterizes the instincts we
have already listed, both the responses to organic needs and the
responses to other people. But there are other instincts with less of
survival value, but no less of play value, and these we call the play
instincts, without attaching any great importance to the name or even
to the classification.


Playful activity.

The kicking and throwing the arms about that we see in a well-rested
baby is evidently satisfying on its own account. It leads to no result
of consequence, except indeed that the exercise is good for the
child's muscles and nerves. The movements, taken singly, are not
uncoordinated by any means, but they accomplish no definite result,
produce no definite change in external objects, and so seem random and
aimless to adult eyes. It is impossible to specify the stimulus for
any given movement, though probably stimuli from the interior of the
body first arouse these responses. They are most apt to occur during
the organic state of "euphoria", and tend to disappear during fatigue.

There is a counter-tendency to this tendency towards general activity,
and that is _inertia_, the tendency towards inactivity or _economy of
effort_. Most pronounced in fatigue, this also appears in lassitude
and inert states that cannot be called fatigue because not brought on
by excessive activity. After sleep, many people are inert, and require
a certain amount of activity to "warm up" to the active condition. As
the child grows older, the {152} "economy of effort" motive becomes
stronger, and the random activity motive weaker, so that the adult is
less playful and less responsive to slight stimuli. He has to have
some definite goal to get up his energy, whereas the child is active
by preference and just for the sake of activity.

During the first year or so of the child's life, his playful activity
takes shape in several ways. First, out of the great variety of the
random movements certain ones are picked out and fixed. This is the
way with putting the hand into the mouth or drumming on the floor with
the heels, and these instances illustrate the important fact that many
learned acts develop out of the child's random activity. Without play
activity there would be little work or accomplishment of the
distinctively human type. Second, certain specific movements, those of
locomotion and vocalization, appear with the ripening of the child's
native equipment, and take an important place in his play. Third, his
play comes to consist more and more of responses to external objects,
instead of to internal stimuli as at first. The playful responses to
external objects fall into two classes, according as they manipulate
objects or simply examine them.

We have, then, a small group of instincts that is very closely related
to the fundamental instinct of random activity.


Locomotion.

Evidence has already been presented [Footnote: See p. 95.] indicating
that walking is instinctive and not learned, so that the human species
is no exception to the rule that every species has its instinctive
mode of locomotion. Simpler performances which enter into the very
complex movement of walking make their appearance separately in the
infant before being combined into walking proper. Holding up the head,
sitting up, kicking with an alternate motion of the {153} two legs,
and creeping, ordinarily precede walking and lead up to it.

What is the natural stimulus to locomotion? It is as difficult to say
as it is to specify the stimulus in other forms of playful activity.
From the fact that blind children are usually delayed in beginning to
walk, we judge that the sense of sight furnishes some of the most
effective stimuli to this response. Often the impulse attending
locomotion is the impulse to approach some seen object, but probably
some satisfaction is derived simply from the free movement itself.
There certainly is no special emotion going with locomotion.
Locomotion has, of course, plenty of "survival value", and might have
been included among the organic instincts.

Some of the other varieties of human locomotion, such as running and
jumping, are probably native. Others, like hopping and skipping, are
probably learned. As to climbing, there is some evolutionary reason
for suspecting that an instinctive tendency in this direction might
persist in the human species, and certainly children show a great
propensity for it; while the acrobatic ability displayed by those
adults whose business leads them to continue climbing is so great as
to raise the question whether the ordinary citizen is right when he
thinks of man as essentially a land-living or surface-living animal.
As to swimming, the theory is sometimes advanced that this too is a
natural form of locomotion for man, and that, consequently, any one
thrown into deep water will swim by instinct. Experiments of this sort
result badly, the victim clutching frantically at any support, and
sometimes dragging down with him the theorist who is administering
this drastic sort of education. In short, the instinctive response of
a man to being in deep water is the same as in other cases of sudden
withdrawal of solid support; it consists in clinging and is attended
by the emotion of fear.

{154}

Vocalization.

Crying at birth proves voice-production to be a native response, but
we are more interested just here in the playful cooing and babbling
that appear when the child is a few weeks or months old. This cheerful
vocalization is also instinctive, in all probability, since the baby
makes it before he shows any signs of responding imitatively to the
voices of other people. It seems to be one form of the random activity
that goes with euphoria. The child derives satisfaction not so much
from the muscular activity of vocalization as from the sounds that he
produces, so that deaf children, who begin to babble much like other
children, lag behind them as the months go by, from not deriving this
auditory satisfaction from the vocal activity. Though whistling,
blowing a horn, shaking a rattle and beating a drum are not native
responses, it is clear that the child naturally enjoys producing
sounds of various sorts.

The baby's cheerful babbling is the instinctive basis on which his
speech later develops through a process of learning.


Manipulation.

While the first random activity of the baby has nothing to do with
external objects, but simply consists of free movements of the arms
and legs, after a time these give place to manipulation of objects.
The baby turns things about, pulls and pushes them, drops them, throws
them, pounds with them. Thus he acquires skill in handling things and
also learns how things behave. This form of playful activity contains
the germ of constructiveness and of inventiveness, and will come into
view again under the head of "imagination."


Exploration or curiosity.

Along with manipulation goes the examination of objects by the hand,
the mouth, the eyes and ears, and all the senses. Listening to a
sudden noise is one of the first exploratory reactions. Following a
moving light with the eyes, fixing the eyes upon a {155} bright
object, and exploring an object visually by looking successively at
different parts of it, appear in the first few months of the baby's
life. Exploration by the hands and by the mouth appear early. Sniffing
an odor is a similar exploratory response. When the child is able to
walk, his walking is dominated largely by the exploring tendency; he
approaches what arouses his curiosity, and embarks on little
expeditions of exploration. Similar behavior is seen in animals and is
without doubt instinctive. With the acquisition of language, the
child's exploration largely takes the form of asking questions.

The stimulus that arouses this sort of behavior is something new and
unfamiliar, or at least relatively so. When an object has been
thoroughly examined, it is dropped for something else. It is when the
cat has just been brought into a strange house that she rummages all
over it from garret to cellar. A familiar object is "taken for
granted", and arouses little exploratory response.

Quite a group of conscious impulses and emotions goes with exploratory
behavior. The feeling or impulse of curiosity is something that
everybody knows; like other impulses, it is most strongly felt when
the end in view cannot be immediately reached. When you are prevented
by considerations of propriety or politeness from satisfying your
curiosity, then it is that curiosity is most "gnawing". A very
definite emotion that occurs on encountering something extremely novel
and strange is what we know as "surprise", and somewhat akin to this
is "wonder".

Exploration, though fundamentally a form of playful activity, has
great practical value in making the child acquainted with the world.
It contains the germ of seeking for knowledge. We shall have to recur
to this instinct more than once, under the head of "attention" and
again under "reasoning".

{156}

Manipulation and exploration go hand in hand and might be considered
as one tendency rather than two. The child wishes to get hold of an
object, that arouses his curiosity, and he examines it while handling
it. You cannot properly get acquainted with an object by simply
looking at it, you need to manipulate it and make it perform; and you
get little satisfaction from manipulating an object unless you can
watch how it behaves.


Tendencies running counter to exploration and manipulation.

Just as playful activity in general is limited by the counter
tendencies of fatigue and inertia, so the tendency to explore and
handle the unfamiliar is held in check by counter tendencies which we
may call "caution" and "contentment".

Watch an animal in the presence of a strange object. He looks at it,
sniffs, and approaches it in a hesitating manner; suddenly he runs
away for a short distance, then faces about and approaches again. You
can see that he is almost evenly balanced between two contrary
tendencies, one of which is curiosity, while the other is much like
fear. It is not full-fledged fear, not so much a tendency to escape as
an alertness to be ready to escape.

Watch a child just introduced to a strange person or an odd-looking
toy. The child seems fascinated, and can scarcely take his eyes from
the novel object, but at the same time he "feels strange", and cannot
commit himself heartily to getting acquainted. There is quite a dose
of caution in the child's make-up--more in some children than in
others, to be sure--with the result that the child's curiosity gets
him into much less trouble than might be expected. Whether caution is
simply to be identified with fear or is a somewhat different native
tendency, it is certainly a check upon curiosity.

By "contentment" we mean here a liking for the familiar, {157} which
offsets to some extent the fascination of the novel. If you are
perfectly contented, you are not inclined to go out exploring; and
when you have had your fill of the new and strange, you like to get
back to familiar surroundings, where you can rest in content. Just as
playful behavior of all sorts decreases with increasing age, so the
love for exploring decreases, and the elderly person clings to the
familiar. But even children may insist in occupying their own
particular chair, on eating from a particular plate, and on being sung
to sleep always with the same old song. They are "little creatures of
habit", not only in the sense that they readily form habits, but in
the sense that they find satisfaction in familiar ways and things.
Here we see the germ of a "conservative" tendency in human nature,
which balances, to a greater or less extent, and may decidedly
overbalance, the "radical" tendency of exploration.


Laughter.

We certainly must not omit this from our list of instincts, for,
though it does not appear till some time after birth, it has all the
earmarks of an instinctive response. If it were a learned movement, it
could be made at will, whereas, as a matter of fact, few people are
able to produce a convincing laugh except when genuinely amused, which
means when the instinctive tendency to laugh is aroused by some
appropriate stimulus. The emotion that goes with laughing may be
called mirth or amusement, and it is a strongly impulsive state of
mind, the impulse being simply to laugh, with no further end in view.

The most difficult question about laughter is to tell in general
psychological terms what is the stimulus that arouses it. We have
several ingenious theories of humor, which purport to tell; but they
are based on adult humor, and we have as yet no comprehensive genetic
study of laughter, tracing it up from its beginnings in the child.
Laughing certainly belongs with the play instincts, and possibly the
{158} stimulus is no more definite, at first, than that which arouses
other playful activity. The baby seems to smile, at first, just from
good spirits (euphoria). The stimuli that, a little later, arouse a
burst of laughter have an element of what we may call "expected
surprise" (as dropping a rattle and exploding with laughter when it
bangs on the floor, and keeping this up time after time), and this
element can still be detected in various forms of joke that are
effective mirth-provokers in the adult. But why the child should laugh
when tickled, at the same time trying to escape, is a poser. Many
students of humor have subscribed to the theory that what makes us
laugh is a sudden sense of our own superiority, thus attaching
laughter to the self-assertive instinct, soon to be discussed. The
laugh of victory, the laugh of defiance, the laugh of mockery, the sly
or malicious laugh, support this theory, but can it be stretched to
cover the laugh of good humor, the tickle laugh, or the baby's laugh
in general? That seems very doubtful, and we must admit that we do not
know the essential element in a laughter stimulus. One thing is fairly
certain: that, while laughing is a native response, we learn what to
laugh at, for the most part, just as we learn what to fear.


Fighting.

Hold the new-born infant's arms tightly against its sides, and you
witness a very peculiar reaction: the body stiffens, the breath may be
held till the face is "red with anger"; the child begins to cry and
then to scream; the legs are moved up and down, and the arms, if they
can be got free, make striking or slashing movements. In somewhat
older children, any sort of restraint or interference with free
movement may give a similar picture, except that the motor response is
more efficient, consisting in struggling, striking, kicking, and
biting. It is not so much pain as interference that gives this
reaction. You get it if you take away a toy the child is playing with,
or if you forbid {159} the child to do something he is bent on doing.
In animals, the fighting response is made to restraint, to being
attacked, or to being interfered with in the course of feeding, or
mating, or in the instinctive care of the young. The mother lioness,
or dog or cat or hen, is proverbially dangerous; any interference with
the young leads to an attack by the mother. The human mother is no
exception to this rule. In human adults, the tendency to fight is
awakened by any interference with one's enterprises, by being insulted
or got the better of or in any way set down in one's self-esteem.

In general, the stimulus to fighting is restraint or interference. Let
any reaction-tendency be first aroused and then interfered with, and
pugnacious behavior is the instinctive result.

The stimulus may be an inanimate object. You may see a child kick the
door viciously when unable to open it; and grown-ups will sometimes
tear, break or throw down angrily any article which they cannot make
do as they wish. A bad workman quarrels with his tools. Undoubtedly,
however, interference from other persons is the most effective
stimulus.

The impulse so aroused is directed primarily towards getting rid of
the restraint or interference, but also towards inflicting damage on
the opponent; and with this impulse often goes the stirred-up organic
and emotional state of anger. As brought out in the chapter on
emotion, the organic state in anger is nearly or quite identical with
that in fear of the active type; and the two states of the individual
differ in respect to impulse rather than in respect to emotion. In
fear, the impulse is to get away from the adversary, in anger to get
at him. The emotion of anger is not always aroused in fighting, for
sometimes there is a cold-blooded desire to damage the adversary.

The motor response, instinctively consisting of struggling, kicking,
etc., as already described, becomes modified {160} by learning, and
may take the form of scientific fistwork, or the form of angry talk,
favored by adults. Or, the adversary may be damaged in his business,
in his possessions, in his reputation, or in other indirect ways. The
fighting spirit, the most stimulating of the emotions, gives energy to
many human enterprises, good as well as bad. The successful reformer
must needs be something of a fighter.

Thus far we have said nothing to justify our placing fighting here
among the play instincts. Fighting against attack has survival value,
fighting to protect the young has survival value, and, in general, the
defensive sort of fighting has survival value, even though
interference with play activity is just as apt to give this response
as interference with more serious activities.

But there is more than this to the fighting instinct. The stimulus of
interference is not always required. Consider dogs. The mere presence
of another dog is often enough to start a scrap, and a good fighting
dog will sally forth in search of a fight, and return considerably
mauled up, which does not improve his chances for survival, to say the
least. Fighting of this aggressive sort is a luxury rather than a
necessity. It has play value rather than survival value. There can be
no manner of doubt that pugnacious individuals, dogs or men, get more
solid satisfaction from a good fight than from any other amusement.
You see people "itching for a fight", and actually "trying to pick a
quarrel", by provoking some other person who is strictly minding his
own business and not interfering in the least. A battle of words
usually starts in some such way, with no real reason, and a battle of
words often develops into a battle of tooth and nail. Two women were
brought before the judge for fighting, and the judge asked Mrs. Smith
to tell how it started. "Well, it was this way, your honor. I met Mrs.
Brown carrying a basket on her arm, and I says {161} to her, 'What
have ye got in that basket?' says I. 'Eggs', says she. 'No!' says I.
'Yes!' says she. 'Ye lie!' says I. 'Ye lie!' says she. And a 'Whoop!'
says I, and a 'Whoop!' says she; and that's the way it began, sir."

We have, then, to recognize aggressive fighting, in addition to
defensive, and the aggressive sort certainly belongs among the play
instincts.

The instincts that by acting counter to fighting hold it in check are
several: laughter--a good laugh together allays hostility; or the
parental instinct--a parent will stand treatment from his child that
he would quickly resent from any one else; or self-assertion--"Too
proud to fight!" But the most direct checks are afforded by
inertia--"What's the use?"--and especially by fear and caution.

Fighting, both defensive and aggressive, has so close a connection
with the more generalized self-assertive tendency that it might be
included under that instinct. It may be regarded as a special form of
self-assertive behavior, often complicated with the emotion of anger.


Self-assertion.

What then is this wonderful instinct of self-assertion, to which
fighting and much of laughing are subordinate? "Assertiveness",
"masterfulness", and the "mastery impulse" are alternative names. Of
all the native tendencies, this is the one most frequently aroused,
since there is scarcely a moment of waking (or dreaming) life when it
is not more or less in action. It is so much a matter of course that
we do not notice it in ourselves, and often not in other persons; and
even clever psychological observers have seemed entirely blind to it,
and given it no place in their list of instincts.

Self-assertion, like fighting, has two forms, the defensive and the
aggressive, and in either case it may be a response to either people
or things. That gives four varieties of self-assertive behavior, which
may be labeled as follows:

{162}

1. Defensive reaction to things, overcoming obstruction, putting
through what has been undertaken--the success motive.

2. Defensive reaction to persons, resisting domination by them--the
independence motive.

3. Aggressive reaction to things--seeking for power.

4. Aggressive reaction to persons--seeking to dominate. We will take
these up in order, beginning with the most elemental.

1. Overcoming obstruction. The stimulus here is much the same as that
which induces fighting, but the response is simpler, without anger and
without the impulse to do damage. Take hold of a baby's foot and move
it this way or that, and you will find that the muscles of the leg are
offering resistance to this extraneous movement. Obstruct a movement
that the baby is making, and additional force is put into the movement
to overcome the obstruction. An adult behaves in a similar way. Let
him be pushing a lawn-mower and encounter unexpected resistance from a
stretch of tough grass; involuntarily he pushes harder and keeps on
going--unless the obstruction is too great. Let him start to lift
something that is heavier than he thinks; involuntarily he "strains"
at the weight, which means that a complex instinctive response occurs,
involving a rigid setting of the chest with holding of the breath, and
increased muscular effort. This instinctive reaction may be powerful
enough to cause rupture.

Other than purely physical resistance is overcome by other
self-assertive responses. When the child's toy will not do what he
wants it to do, he does not give up at once, but tries again and puts
more effort into his manipulation. When, in school, he is learning to
write, and finds difficulty in producing the desired marks, he bends
over the desk, twists his foot round the leg of his chair, screws up
his face, {163} and in other ways reveals the great effort he is
making. An adult, engaged in some piece of mental work, and
encountering a distraction, such as the sound of the phonograph
downstairs, may, of course, give up and listen to the music, but, if
he is very intent on what he is doing, he puts more energy into his
work and overcomes the distraction. When he encounters a baffling
problem of any sort, he does not like to give it up, even if it is as
unimportant as a conundrum, but cudgels his brains for the solution.
As a general proposition, and one of the most general propositions
that psychology has to present, we may say that obstruction of any
sort, encountered in carrying out any intention whatever, acts as a
stimulus to the putting of additional energy into the action.

Anger is often aroused by obstruction, but anger does not develop a
tenth as often, in the course of the day, as the plain overcoming
reaction. The impulse is not to do damage, but to overcome the
obstruction and do what we have set out to do. The emotional state
might sometimes be called "determination", sometimes "zeal"; but the
most elementary state belonging here is _effort_. The feeling of
effort is, partly at least, a sensation complex resulting from
stiffening the trunk and neck, knitting the brows, and other muscular
strains that have practical utility in overcoming physical resistance
and that are carried over to the overcoming of other sorts of
resistance, where they have no obvious utility. Effort is a simpler
emotion than anger, and occurs much more frequently.

2. Resisting domination by other persons. The child shows from an
early age that he "has a will of his own", and "wants his own way" in
opposition to the commands of other persons. There is an independent
spirit in man that is native rather than acquired. The strength of
this impulse differs, to be sure, in different individuals, some {164}
children being more "contrary" and others more docile; but there
probably never was a child without a good dose of disobedience in his
make-up. In order to have a nice, obedient child, you have to "break"
him like a colt, though you can use reason as well as force in
breaking a child. This process of "breaking" gives a habit of
obedience to certain persons and along certain lines; but, outside of
these limits, the child's independence is still there and ready to be
awakened by any attempt to dominate him. In youth, with the sense of
power that comes from attaining adult stature and muscular strength,
the independent spirit is strengthened, with the result that you
seldom see a youth, or an adult, who can take orders without at least
some inner opposition and resentment.

3. Seeking for power over things. The self-assertive response to
things is not limited to overcoming the obstructions offered by things
to the accomplishment of our purposes; but we derive so much positive
satisfaction from overcoming obstruction and mastering things that we
go out in search of things to master. The child's manipulation has an
element of masterfulness in it, for he not only likes to see things
perform, but he likes to be the one that makes them perform. If he has
a horn, he is not satisfied till he can sound it himself. The man with
his automobile is in the same case. When it balks, he is stimulated to
overcome it; but when it runs smoothly for him, he has a sense of
mastery and power that is highly gratifying. Chopping down a big tree,
or moving a big rock with a crowbar, affords the same kind of
gratification; and so does cutting with a sharp knife, or shooting
with a good bow or gun, or operating any tool or machine that
increases one's power. Quite apart from the utility of the result
accomplished, any big achievement is a source of satisfaction to the
one who has done it, because it gives play to aggressive
self-assertion. Many {165} great achievements are motived as much by
the zest for achievement as by calculation of the advantages to be
secured.

4. Seeking to dominate other people. The individual not simply resists
domination by other people, but he seeks to dominate them himself.
Even the baby gives orders and demands obedience. Get a number of
children together, and you will see more than one of them attempt to
be the leader in their play. Some must necessarily be followers just
now, but they will attempt to take the lead on another occasion. The
"born leader" is perhaps one who has an exceptionally strong dose of
masterfulness in his make-up, but he is, still more, one who has
abilities, physical or mental, that give him the advantage in the
universal struggle for leadership.

Besides giving orders and taking the lead, there are other ways in
which the child finds satisfaction for his instinct to dominate.
Showing off is one, bragging is one, doing all the talking is one;
and, though in growing older and mixing with people the child becomes
less naive in his manner of bragging and showing off, he continues
even as an adult to reach the same end in more subtle ways. Going
about to win applause or social recognition is a seeking for
domination. Anything in which one can surpass another becomes a means
of self-assertion. One may demonstrate his superiority in size,
strength, beauty, skill, cleverness, virtue, good humor,
cooeperativeness, or even humility, and derive satisfaction from any
such demonstration. The impulse to dominate assumes literally a
thousand disguises, more rather than less.

_Rivalry_ and _emulation_, sometimes accorded a separate place in a
list of the instincts, seem well enough provided for under the general
head of self-assertion. They belong on the social side of assertive
behavior, i.e., they are responses to other people and aim at the
domination of other {166} people or against being dominated by them.
But the struggle for mastery, in rivalry, does not take the form of a
direct personal encounter. Compare wrestling with a contest in
throwing the hammer. In wrestling the mastery impulse finds a direct
outlet in subduing the opponent, while in throwing the hammer each
contestant tries to beat the other indirectly, by surpassing him in a
certain performance. This you would call rivalry, but wrestling is
scarcely rivalry, because the struggle for mastery is so direct.
Rivalry may seek to demonstrate superiority in some performance, or to
win the favor of some person or social group, as in the case of rivals
in love.

When we speak of "emulation", we have in mind the sort of behavior
observed when one child says, "See what I can do!" and the other
counters with, "Pooh! I can do that, too". Or, the first child wins
applause by some performance, and we then notice the second child
attempting the same. It is a case of resisting the indirect domination
of another, by not letting him surpass us in performance or in social
recognition.

_Thwarted self-assertion_ deserves special mention, as the basis for
quite a number of queer emotional states. Shame, sulkiness,
sullenness, peevishness, stubbornness, defiance, all go with wounded
self-assertion under different conditions. Envy and jealousy belong
here, too. Shyness and embarrassment go with self-assertion that is
doubtful of winning recognition. Opposed to all these are
self-confidence, the cheerful state of mind of one who seeks to master
some person or thing and fully expects to do so, and elation, the
joyful state of one who has mastered.


Submission.

Is there any counter-tendency that limits self-assertion and holds it
in check? Inertia and fear of course have this effect, but is there
any specific instinct precisely opposite to self-assertion? A
difficult question, not {167} yet to be answered with any assurance;
but there is some evidence of a native submissive or yielding
tendency. Two forms may be distinguished: yielding to obstruction, and
yielding to the domination of other persons.

Giving up, in the face of obstacles, is certainly common enough, but
at first thought we should say that the individual was passive in the
matter, and simply forced to yield, as a stone is brought to a stop
when it strikes a wall. In reality, giving up is not quite so passive
as this. There is no external force that can absolutely force us to
give up, unless by clubbing us on the head or somehow putting our
reactive mechanism out of commission. As long as our brain, nerves and
muscles are able to act, no external force can absolutely compel us to
cease struggling. Since, then, we do cease struggling before we are
absolutely out of commission, our giving up is not a purely passive
affair, but our own act, a kind of reaction; and no doubt a native
reaction. Further, when struggling against a stubborn obstacle, we
sometimes feel an _impulse to give up_, and giving up brings relief.

The ability to give up is not a mere element of weakness in our
nature, but is a valuable asset in adapting ourselves to the
environment. Adaptation is called for when the reaction first and most
naturally made to a given situation does not meet the requirements of
the situation. A too stubborn assertiveness means persistence in this
unsuitable reaction, and no progress towards a successful issue;
whereas giving up the first plan of attack, and trying something else
instead, is the way towards success. Some people are too stubborn to
be adaptable.

The docility of the child, who believes whatever is told him, has in
it an element of submissiveness. There is submissiveness also in the
receptive attitude appropriate in observation and forming
opinions--the attitude of looking for the facts and accepting them as
they are rather than seeking {168} to confirm one's own
prepossessions. Bias is self-assertive, impartiality is submissive to
some degree.

Yielding to the domination of other persons often occurs unwillingly,
and then comes under the head of "thwarted self-assertion"; but the
question is whether it ever occurs willingly and affords satisfaction
to the individual who yields. We certainly yield with good grace to
one who so far outclasses us that competition with him is unthinkable.
An adult may arouse the submissive response in a child; and the social
group, by virtue of its superior power and permanence, may arouse it
in the individual adult. Hero worship seems a good example of willing
submission, agreeable to the one who submits. There are persons who
are "lost" without a hero, without some one to lean on, some one to
tell them what to do and even what to believe. This looks much like
the "filial" or "infantile" instinct that was mentioned before as a
possibility, and the dependent spirit in an adult possibly represents
a continuation of the infantile attitude into adult life.

Some behavior that looks submissive is really self-assertion in
disguise. There are two forms of self-assertion that are specially
likely to be taken for submission. Wounded or thwarted self-assertion
is one. Shame and envy are like submission in this respect, that they
involve an absence of self-confidence or self-assurance, but they do
not afford the satisfaction of willing submission, nor the relief of
giving up the struggle against obstacles. So far from being genuinely
submissive, they are states in which the self is making a violent and
insistent demand for justification or social recognition. The other
form of self-assertion which looks like submission occurs when a
person identifies himself with a superior individual or with a social
group. He will then boast of the prowess of his hero or of the
prestige of his group, whether it be his family, his school, {169} his
town or his country. Now, boasting cannot by any stretch of the
imagination be regarded as a sign of submissiveness; it is a sign of
assertiveness, and nothing else. What has happened here is that the
individual, having identified himself with his hero or his group,
finds in their greatness a means of asserting himself as against other
individuals who have not the good fortune to be so identified. This
transferred self-assertion is a strong element in loyalty and public
spirit, and plays a large and useful part in public affairs.

{170}

EXERCISES

1. Make an outline of the chapter, in the form of a table, which
   shall show for each instinct: (a) the natural stimulus, (b) the
   native motor response, (c) the end-result that the instinct tends
   towards, in its adult as well as its native condition, and (d) the
   emotion, if any, that goes with the activity of the instinct.

2. An adult tendency or propensity may be simply an unmodified
   instinct, or it may be derived from instincts by combination, etc.
   Try to identify each of the following as an instinct, or to analyze
   it into two or more instincts:

   (a) Love for adventure.
   (b) Patriotism.
   (c) A father's pride in his children.
   (d) Love for travel.
   (e) Insubordination.
   (f) Love for dancing.

3. Which of the instincts are most concerned in making people work?

4. Show how self-assertion finds gratification in the life-work of

   an actor.
   a physician.
   a housekeeper.
   a teacher.
   a railroad engineer.

5. Arrange the following impulses and emotions in the order of the
   frequency of their occurrence in your ordinary day's work and play:

   (a) Fear.
   (b) Anger.
   (c) Disgust
   (d) Curiosity.
   (e) Self-assertion.
   (f) Submission.
   (g) The tendency to protect or "mother" another.

6. How do "practical jokes" lend support to the view that laughter
   is primarily aroused by a sense of one's own superiority?

7. Get together a dozen jokes or funny stories, and see how many
   of them can be placed with the practical jokes in this respect.

8. Mention some laughter-stimuli that do not lend support to the
   theory mentioned in Exercise 6.

9. What instincts find outlet in (a) dress, (b) automobiling, (c)
   athletics, (d) social conversation?



{171}



REFERENCES

McDougall's _Social Psychology_ gives, in Chapters III and IV, an
inventory of the instinctive equipment of mankind, and in Chapter V
attempts to analyze many complex human emotions and propensities into
their native elements.

Thorndike, in his _Educational Psychology, Briefer Course_, 1914,
Chapters, II-V, attempts a more precise analysis of stimulus and
response.

Watson's _Psychology from the Standpoint of a Behaviorist_, 1919,
attempts in Chapter VI to show that there are only three primary
emotions, fear, rage and love; and in Chapter VII gives a critical
review of the work on human instincts.

H. C. Warren, in Chapter VI of his _Human Psychology_, 1919, gives a
brief survey of the reflexes and instincts.


{172}


CHAPTER IX

THE FEELINGS


PLEASANTNESS AND UNPLEASANTNESS, AND OTHER
STATES OF FEELINGS AND THEIR INFLUENCE UPON
BEHAVIOR

Feeling is subjective and unanalyzed. It is conscious, and an
"unconscious feeling" would be a contradiction in terms. But, while
conscious, it is not cognitive; it is not "knowing something", even
about your subjective condition; it is simply "the way you feel". As
soon as you begin to analyze it, and say, "I feel badly here or there,
in this way or in that", you _know_ something about your subjective
condition, but the feeling has evaporated for the instant. In passing
over into definite knowledge of facts, it has ceased to be feeling.

Feeling is an undercurrent of consciousness, or we might call it a
background. The foreground consists of what you are taking notice of
or thinking about, or of what you are intending to do; that is to say,
the foreground is cognitive or impulsive, or it may be both at once,
as when we are intent on throwing this stone and hitting that tree. In
the background lies the conscious subjective condition. Behind facts
observed and acts intended lies the state of the individual's feeling,
sometimes calm, sometimes excited, sometimes expectant, sometimes
gloomy, sometimes buoyant.

The number of different ways of feeling must be very great, and it
would be no great task to find a hundred different words, some of them
no doubt partly synonymous, to complete the sentence, "I feel
_______". All the {173} emotions, as "stirred-up states of mind",
belong under the general head of the feelings.

But when the psychologist speaks of _the feelings_, he usually means
the _elementary_ feelings. An emotion is far from elementary. If you
accept the James-Lange theory, you think of an emotion as a blend of
organic sensations; and if you reject that theory, you would still
probably agree that such an emotion as anger or fear seems a big,
complex state of feeling. It seems more complex than such a sensation
as red, warm, or bitter, which are called elementary sensations
because no one has ever succeeded in decomposing them into simpler
sensations. Now, the question is whether any feelings can be indicated
that are as elementary as these simple sensations.


Pleasantness and Unpleasantness Are Simple Feelings

No one has ever been able to break up the feelings of pleasantness and
unpleasantness into anything simpler. "Pleasure" and "displeasure" are
not always so simple; they are names for whole states of mind which
may be very complex, including sensations and thoughts in addition to
the feelings of pleasantness and unpleasantness. "Pain" does not make
a satisfactory substitute for the long word "unpleasantness", because
"pain", as we shall see in the next chapter, is properly the name of a
certain sensation, and feelings are to be distinguished from
sensations. Red, warm and bitter, along with many others, are
sensations, but pleasantness and unpleasantness are not sensations.

How, then, do the elementary feelings differ from sensations? In the
first place, sensations submit readily to being picked out and
observed, and in fact become more vivid when they are brought into the
"foreground", while feelings grow vague and lose their character when
thus singled {174} out for examination. Attend to the noises in the
street and they stand out clearly, attend to the internal sensation of
breathing and it stands out clearly, but attend to your pleasant state
of feeling and it retreats out of sight.

In the second place, sensations are "localized"; you can tell pretty
well where they seem to come from. Sensations of light, sound and
smell are localized outside the body, sensations of touch are
localized on the skin (or sometimes outside), taste sensations are
localized in the mouth, organic and muscular sensations in some part
of the body. On the other hand, pleasantness and unpleasantness are
much less definitely localized; they seem to be "in us", without being
in any special part of us.

In the third place, feelings differ from sensations in having no known
sense organs. There is no special sense organ or set of sense organs
for the feeling of pleasantness or unpleasantness, as there is for
warmth or cold. Some sensations are pleasant, to be sure, and some
unpleasant; but there is no one kind of sense organ that has the
monopoly of either sort of feeling.


Feeling-Tone of Sensations

The pleasantness or unpleasantness characteristic of many sensations
is called their "feeling-tone", and sensations that are markedly
pleasant or unpleasant are said to have a strong or pronounced
feeling-tone. Bitter is intrinsically unpleasant, sweet pleasant, the
salty taste, when not too strong, neither one nor the other, so that
it has no definite feeling-tone. Odors, as well as tastes, usually
have a rather definite feeling-tone. Of sounds, smooth tones are
pleasant, grating noises unpleasant. Bright colors are pleasant, while
dull shades are sometimes unpleasant, sometimes merely indifferent or
lacking in feeling-tone. Pain is usually unpleasant, moderate warmth
and cold pleasant, simple touch {175} indifferent. Very intense
sensations of any kind are likely to be unpleasant.

The statements made above as to the subjectivity and non-localization
of feeling do not apply altogether to the feeling-tone of sensations.
The pleasantness or unpleasantness of a sensation is localized with
the sensation and seems to belong to the object rather than to
ourselves. The unpleasantness of a toothache seems to be in the tooth
rather than simply "in us". The pleasantness of a sweet taste is
localized in the mouth, and we even think of the sweet substance as
being objectively pleasant. We say that it is a "pleasant day", and
that there is a "pleasant tang in the air", as if the pleasantness
were an objective fact.

By arguing with a person, however, you can get him to admit that,
while the day is pleasant _to him_, and the tang in the air pleasant
to him, they may be unpleasant to another person; and he will admit
that a sweet substance, ordinarily pleasant, is unpleasant when he has
had too much of sweet things to eat. So you can make him realize that
pleasantness and unpleasantness depend on the individual and his
condition, and are subjective rather than objective. Show a group of
people a bit of color, and you will find them agreeing much better as
to what color that is than as to how pleasant it is. Feeling-tone is
subjective in the sense that people disagree about it.


Theories of Feelings

1. Pleasantness might represent a general _organic state_, and
unpleasantness the contrary state, each state being an internal bodily
response to pleasant or unpleasant stimuli, and making itself felt as
an unanalyzable compound of vague internal sensations.

This theory of feeling is certainly attractive, and it would {176}
account very well for all the facts so far stated, for the
subjectivity of feeling, for its lack of localization, and for the
absence of specific sense organs for the feelings. It would bring the
feelings into line with the emotions. But the real test of the theory
lies just here: can we discover radically different organic states for
the two opposite feelings?

Numerous experiments have been conducted in the search for such
radically different organic states, but thus far the search has been
rather disappointing. Arrange to record the subject's breathing and
heart beat, apply pleasant and unpleasant stimuli to him, and see
whether there is any characteristic organic change that goes with
pleasant stimuli, and an opposite change with unpleasant stimuli. You
should also obtain an introspective report from your subject, so as to
be sure that the "pleasant stimuli" actually gave a feeling of
pleasantness, etc. Certain experiments of this sort have indicated
that with pleasantness goes slower heart beat and quicker breathing,
with unpleasantness quicker heart beat and slower breathing. But not
all investigators have got these results; and, anyway, it would be
impossible to generalize to the extent of asserting that slow heart
beat always gave a pleasant state of feeling, and rapid heart beat an
unpleasant; for there is slow heart beat during a "morning grouch",
and rapid during joyful expectation. Or, in regard to breathing, try
this experiment: hasten your breathing and see whether a feeling of
pleasantness results; slacken it and see whether unpleasantness
results. The fact is that pleasantness can go with a wide range of
organic states, so far as these are revealed by heart beat and
breathing; and the same with unpleasantness. If there is any organic
fact definitely characteristic of either state of feeling, it is a
subtle fact that has hitherto eluded observation.

{177}

2. Pleasantness might represent smooth and easy brain action,
unpleasantness slow and impeded brain action. According to this
theory, unimpeded progress of nerve currents through the brain is
pleasant, while resistance encountered at the brain synapses is
unpleasant. A stimulus is pleasant, then, because the nerve currents
started by it find smooth going through the brain centers, and another
stimulus is unpleasant because it finds the going poor.

While this theory looks good in some ways, and fits some cases very
well--as the great unpleasantness of blocked reaction, where you
cannot make up your mind what to do--there are two big objections to
it. The first objection is found in the facts of practice. Practising
any reaction makes it more and more smooth-running and free from inner
obstruction, and should therefore make it more and more pleasant; but,
as a matter of fact, practising an unfamiliar act of any sort makes it
more pleasant for a time only, after which continued practice makes it
automatic and neither pleasant nor unpleasant. The smoothest
reactions, which should give the highest degree of pleasant feeling
according to the theory, are simply devoid of all feeling.

The second objection lies in the difficulty of believing unpleasant
stimuli to give slow, impeded reactions. On the contrary, the
instinctive defensive reactions to unpleasant stimuli are very quick,
and give no sign of impeded progress of nerve currents through the
brain centers.

3. There is one fact, not yet taken into account, that may point the
way to a better theory. Feeling is impulsive. In pleasantness, the
impulse is to "stand pat" and let the pleasant state continue; in
unpleasantness, the impulse is to end the state. The impulse of
pleasantness is directed towards keeping what is pleasant, and the
impulse of unpleasantness is directed towards getting rid of the
unpleasant. In indifference there is no tendency either to keep or to
be {178} rid of. These facts are so obvious as scarcely to need
mention, yet they may be the core of this whole matter of feeling.
Certainly they are the most important facts yet brought out as
relating feeling to conduct.

Putting this fact into neural terms, we say that pleasantness goes
with a neural adjustment directed towards keeping, towards letting
things stay as they are; while unpleasantness goes with an adjustment
towards riddance. Bitter is unpleasant because we are so organized, by
native constitution, as to make the riddance adjustment on receiving
this particular stimulus. In plain language, we seek, to be rid of it,
and that is the same as saying it is unpleasant. Sweet is pleasant for
a similar reason.

There is some evidence that these adjustments occur in that part of
the brain called the thalamus. [Footnote: See p. 65.]


Sources of Pleasantness and Unpleasantness

Laying aside now the difficult question of the organic and cerebral
nature of the feelings, we turn to the simpler question of the stimuli
that arouse them. A very important fact immediately arrests our
attention. There are two different kinds of stimuli for pleasantness,
and two corresponding kinds for unpleasantness. The one kind is
typified by sweet and bitter, the other by success and failure. Some
things are pleasant (or unpleasant) without regard to any already
awakened desire, while other things are pleasant (or unpleasant) only
because of such a desire. A sweet taste is pleasant even though we
were not desiring it at the moment, and a bitter taste is unpleasant
though we had no expectation of getting it and no desire awakened to
avoid it. On the other hand, the sight of our stone hitting the tree
is pleasant only because we were aiming at the tree, and {179} the
sight of the stone going to one side of the tree is unpleasant just
for the same reason.

  Some things we want.
    Because we like them;
  Some things we like.
    Because we want them.

We want candy, because we like the sweet taste; but we like a cold
drink because and when we are thirsty and not otherwise. Thirst is a
want for water, a state of the organism that impels us to drink; and
when we are in this state, we like a drink, a drink is pleasant then.
How absurd it would be to say that we were thirsty because we liked to
drink! when the fact is that we like to drink because we are thirsty.
The desire to drink must first be aroused, and then drinking is
pleasant.

What is true of thirst is true of hunger, or of any organic need. The
need must first be aroused, and then its satisfaction is pleasant.
This applies just as well to fighting, laughing, fondling a baby, and
to all the instincts. It gives you no pleasure to strike or kick a
person, or to swear at him, unless you are first angry with him. It
gives you no pleasure to go through the motions of laughing unless you
"want to laugh", i.e., unless you are amused. It gives you no pleasure
to fondle the baby unless you love the baby. Let any instinct be first
aroused, and then the result at which the instinct is aimed causes
pleasure, but the same result will cause no pleasure unless the
instinct has been aroused.

The same can be said of desires that are not exactly instinctive. At a
football game, for example, when one of the players kicks the ball and
it sails between the goal posts, half of the spectators yell with joy,
while the other half {180} groan in agony. Why should the appearance
of a ball sailing between two posts be so pleasant to some, and
unpleasant to others? This particular appearance is by itself neither
pleasant nor unpleasant, but because the desire to see this happen has
been previously aroused in the partisans of one team, and the desire
that it should not happen in the partisans of the other, therefore it
is that the pleasantness or unpleasantness occurs. First arouse any
desire, and then you can give pleasure by gratifying it, displeasure
by thwarting it. This is the pleasure of success, and the
unpleasantness of failure.

Pleasures of this class may be named secondary, because they depend
upon pre-aroused desires.


Primary Likes and Dislikes

Though many of the most intense pleasures and displeasures of life are
of the secondary type, this fact must not blind us to the existence of
the primary pleasures and displeasures, typified by sweet and bitter.
Any sensation with a pronounced feeling-tone is a primary pleasure or
displeasure. We like or dislike it just for itself, and without regard
to the gratification of any pre-aroused instinct or desire.

There are natural likes and dislikes--apart from the satisfaction of
instincts--and there are others that are acquired. In other words,
there are native tastes and acquired tastes. Individuals differ
considerably in their native tastes, and still more in their acquired
tastes. Liking for sweets is native, liking for fragrant odors is
native, but liking for lemonade, or black coffee, or olives, or
cheese, is acquired, and not acquired by everybody. Liking for bright
colors is native, but liking for subdued colors, and the special
pleasure in color harmonies, are acquired. So we might {181} run
through the list of the senses, finding under each some sensations
with native feeling-tone, and other sensations that acquire
feeling-tone through experience.

Some people have a native liking for numbers and other facts of a
mathematical nature. We say of such a one that he has a natural taste
for mathematics. Another has a natural dislike for the same. Some have
a taste for things of the mechanical sort, others fight shy of such
things. Some have a natural taste for people, being sociable
creatures--which means more than being gregarious--while others are
little interested in mixing with people, observing their ways, and the
give and take of friendly intercourse.

Now the question arises whether these native likes and dislikes, for
odors, colors, tones, numbers, machinery, and people, are really
independent of the instincts. Some psychologists have insisted that
all the interest and satisfaction of life were derived from the
instincts, laying special stress on the instincts of curiosity and
self-assertion.

With respect to our "natural liking for mathematics", these
psychologists would argue as follows: "First off, curiosity is aroused
by numbers, as it may be by any novel fact; then the child, finding he
can do things with numbers, gratifies his mastery impulse by playing
with them. He encounters number problems, and his mastery impulse is
again aroused in the effort to solve the problems. Later, he is able
to 'show off' and win applause by his mathematical feats, and thus the
social form of self-assertion is brought into play. This particular
child may have good native ability for mathematics, and consequently
his mastery impulse is specially gratified by this kind of activity;
but he has no real direct liking for mathematics, and all his industry
in this field is motivated by curiosity and especially by
self-assertion."

The instinct psychologists have a strong case here, as {182} they
would have also in regard to the liking for machinery. Still, the
mathematical individual would not be convinced, for he would testify
that numbers, etc., made a direct appeal to him. Numbers, geometric
forms, and algebraic transformations are fascinating to him, and there
is something beautiful, to his mind, in the relationships that are
discovered. The same could be said of the liking for plant or animal
life that appears in the "born biologist". If the objects of the world
make a direct appeal to the man whose mind is attuned to them, then
his interest and zeal in studying them are not wholly derived from the
instincts. The instincts come into play, truly enough, in all
scientific work, and add impetus to it, but the primary motive is a
direct liking for the kind of facts studied.

"Primary likes and dislikes" are still more clearly in evidence in the
arts than in the sciences. Take the color art, for example. There can
be no manner of doubt that bright colors are natively pleasant. Can we
explain the liking for color as derived from satisfaction of the
instincts? Is it due simply to curiosity? No, for then the color would
no longer be attractive after it had ceased to be a novelty. Is color
liked simply for purposes of self-display? No, this would not explain
our delight in the colors of nature. Or do color effects constitute
problems that challenge the mastery impulse? This might fit the case
of intricate color designs, but not the strong, simple color effects
that appeal to most people. There is no escape from the conclusion
that color is liked for its own sake, and that this primary liking is
the foundation of color art.

Music, in the same way, is certainly based on a primary liking for
tones and their combinations, as well as for rhythm. Novel effects
also appeal to curiosity, musical performance is a means of display to
the performer, and the problem set by a piece of music to the
performer in the {183} way of execution, and to the listener in the
way of understanding and appreciation, gives plenty of play to the
mastery impulse. Besides, music gets associated with love, tenderness,
war and religion; but none of the impulses thus gratified by music is
the fundamental reason for music, since without the primary taste for
tone and rhythm there would be no music to start with, and therefore
no chance for these various impulses to find an outlet in this
direction.

Still another field of human activity, in which native likes and
dislikes play their part alongside of the instincts, is the field of
social life. The gregarious instinct brings individuals together into
social groups, and probably also makes the individual crave
participation in the doings of the group. The sex instinct lends a
special interest to those members of the group who are of the opposite
sex, and the parental instinct leads the adults to take a protective
attitude towards the little children. Also, it is probably due to the
parental instinct that any one spontaneously seeks to help the
helpless. Self-assertion has plenty of play in a group, both in the
way of seeking to dominate and in the way of resisting domination; and
the submissive tendency finds an outlet in admiring and following
those who far surpass us. Thwarted self-assertion accounts for many of
the dislikes that develop between the members of a group. But none of
these instincts accounts for the interest in personality, or for the
genuine liking that people may have for one another.

Let a group of persons of the same age and sex get together, all
equals for the time being, no one seeking to dominate the rest, no one
bowing to another as his superior nor chafing against an assumed
superiority which he does not admit, no one in a helpless or
unfortunate condition that arouses the pity of the rest. What an
uninteresting affair! No instincts called into play except bare
gregariousness! {184} On the contrary, such a group affords almost or
quite the maximum of social pleasure. It affords scope for comradeship
and good fellowship, which are based on a native liking for people,
and not on the instincts.

Enough has perhaps been said to convince the reader that, besides the
things we like for satisfaction of our instinctive needs and cravings,
there are other things that we "just naturally like"--and the same
with dislikes--and that these primary likes and dislikes have
considerable importance in life.


Other Proposed Elementary Feelings

Pleasantness and unpleasantness are the only feelings generally
accepted as elementary, though several others have been suggested.


Wundt's tri-dimensional theory of feeling.

This author suggested that there were three pairs of feelings:
pleasantness and unpleasantness; tension and its opposite, release or
relief; and excitement and its opposite, which may be called numbness
or subdued feeling. Thus there would be three dimensions of feeling,
which could be represented by the three dimensions of space, and any
given state of feeling could be described by locating it along each of
the three dimensions. Thus, one moment, we may be in a pleasant,
tense, excited state; another moment in a pleasant, relieved and
subdued state; and another moment in an unpleasant, tense and subdued
state, etc. As each feeling can also exist in various degrees, the
total number of shades of feeling thus provided for would be very
great, indeed.

Though this theory has awakened great interest, it has not won
unqualified approval. Excitement and the rest are real enough states
of feeling--no one doubts that--but the question is whether they are
fit to be placed alongside of pleasantness and unpleasantness as
elementary feelings. It {185} appears rather more likely that they are
blends of sensations. In the excited states that have been most
carefully studied, that is to say, in fear and anger, there is that
big organic upstir, making itself felt as a blend of many internal
sensations. Tension may very probably be the feeling of tense muscles,
for tension occurs specially in expectancy, and the muscles are tense
then.

Whether elementary or not, these feelings are worthy of note. It is
interesting to examine the striving for a goal and the attainment of
the goal with respect to each "dimension" of feeling. Striving is
tense, attainment brings the feeling of release. Striving is often
excited, but fatigue and drowsiness (seeking for rest) are numb, and
self-assertion may be neutral in this respect, as in "cool
assumption". Reaching the goal may be excited or not; all depends on
the goal, whether it be striking your opponent or going to sleep. On
the other hand, reaching the goal is practically always pleasant
(weeping seems an exception here), while striving for a goal is
pleasant or unpleasant according as progress is being made towards the
goal, or stiff obstruction encountered.

The _feeling of familiarity_, and its opposite, the feeling of
strangeness or newness, also have some claim to be considered here.
The first time you see a person, he seems strange, the next few times
he awakens in you the feeling of familiarity, after which he becomes
so much a matter of course as to arouse no definite feeling of this
sort, unless, indeed, a long time has elapsed since you saw him last;
in this case the feeling of familiarity is particularly strong.

The feelings of doubt or hesitation, and of certainty or assurance,
also deserve mention as possibly elementary.

{186}


EXERCISES

1. Outline the chapter.

2. Complete the sentence, "I feel_____" in 20 different ways
   (not using synonyms), and measure the time required to do this.

3. What can be meant by speaking in psychology of only two feelings,
   when common speech recognizes so many?

4. If the states of mind designated by the words, "feeling sure",
   or "feeling bored", are compound states, what elements besides the
   feelings of pleasantness and unpleasantness may enter into the
   compounds?

5. Attempt an analysis of the "worried feeling", by your own
   introspection, i.e., try to discover elementary feelings and
   sensations in this complex state of mind.

6. Following Wundt's three-dimensional scheme of feeling, analyze
   each of the following states of mind (for example, a child just
   admitted to the presence of the Christmas tree would be in a state
   of mind that is pleasant, tense, and excited):

   (a) Watching a rocket go up and waiting for it to burst.

   (b) Just after the rocket has burst.

   (c) Waiting for the dentist to pull.

   (d) Just after he has pulled.

   (e) Enjoying a warm bed.

   (f) Lying abed after waking, not quite able as yet to decide
       to get up.

   (g) Seeing an automobile about to run down a child.

7. Make a list of six primary dislikes, and a list of six dislikes that
   are dependent on the instincts.



REFERENCES

For a much fuller treatment of the subject, see E. B. Titchener,
_Textbook of Psychology_, 1909, pp. 225-264.


{187}


CHAPTER X

SENSATION

AN INVENTORY OF THE ELEMENTARY SENSATIONS OF THE DIFFERENT SENSES

With reflex action, instinct, emotion and feeling, the list of native
mental activities is still incomplete. The senses are provided by
nature, and the fundamental use of the senses goes with them. The
child does not learn to see or hear, though he learns the meaning of
what he sees and hears. He gets sensation as soon as his senses are
stimulated, but recognition of objects and facts comes with
experience. Hold an orange before his open eyes, and he sees, but the
first time he doesn't see _an orange_. The adult sees an object, where
the baby gets only sensation. "Pure sensation", free from all
recognition, can scarcely occur except in the very young baby, for
recognition is about the easiest of the learned accomplishments, and
traces of it can be seen in the behavior of babies only a few days
old.

Sensation is a response; it does not come to us, but is aroused in us
by the stimulus. It is the stimulus that comes to us, and the
sensation is our own act, aroused by the stimulus. Sensation means the
activity of the receiving organ (or sense organ), of the sensory
nerves, and of certain parts of the brain, called the sensory centers.
Without the brain response, there is apparently no conscious
sensation, so that the activity of the sense organ and sensory nerve
is preliminary to the sensation proper. Sensation may be called the
first response of the brain to the external stimulus. It is usually
only the first in a series of brain {188} responses, the others
consisting in the recognition of the object and the utilization of the
information so acquired.

Sensation, as we know it in our experience, goes back in the history
of the race to the primitive sensitivity (or irritability) of living
matter, seen in the protozoa. These minute unicellular creatures,
though having no sense organs--any more than they have muscles or
digestive organs--respond to a variety of stimuli. They react to
mechanical stimuli, as a touch or jar, to chemical stimuli of certain
kinds, to thermal stimuli (heat or cold), to electrical stimuli, and
to light. There are some forces to which they do not respond:
magnetism, X-rays, ultraviolet light; and we ourselves are insensitive
to these agents, which are not to be called stimuli, since they arouse
no response.


The Sense Organs

In the development of the metazoa, or multicellular animals,
specialization has occurred, some parts of the body becoming muscles
with the primitive motility much developed, some parts becoming
digestive organs, some parts conductors (the nerves) and some parts
becoming specialized receptors or sense organs. A sense organ is a
portion of the body that has very high sensitivity to some particular
kind of stimulus. One sense organ is highly sensitive to one stimulus,
and another to another stimulus. The eye responds to very minute
amounts of energy in the form of light, but not in other forms; the
ear responds to very minute amounts of energy in the form of sound
vibrations, the nose to very minute quantities of energy in certain
chemical forms.

There is only one thing that a sense organ always and necessarily
contains, and that is the _termination of a sensory nerve_. Without
that, the sense organ, being isolated, would have no effect on the
brain or muscles or any other {189} part of the body, and would be
entirely useless. The axons of the sensory nerve divide into fine
branches in the sense organ, and thus are more easily aroused by the
stimulus.

Besides the sensory axons, two other things are often found in a sense
organ--sometimes one of the two, sometimes the other and sometimes
both. First, there are special sense cells in a few sense organs; and
second, in most sense organs there is accessory apparatus which,
without being itself sensitive, assists in bringing the stimulus to
the sense cells or sensory nerve ends.


[Illustration: Fig. 25.--Diagram of the taste end-organ. Within the
"Taste bud" are seen two sense cells, and around the base of these
cells are seen the terminations of two axons of the nerve of taste.
(Figure text:  surface of tongue, taste bud, pit)]


_Sense cells_ are present only in the eye, ear, nose and mouth--always
in very sheltered situations. The taste cells are located in little
pits opening upon the surface of the tongue. In the sides of these
pits can be found little flask-shaped chambers, each containing a
number of taste cells. The taste cell has a slender prolongation that
protrudes from the chamber into the pit; and it is this slender tip of
the cell that is exposed to the chemical stimulus of the {190} tasting
substance. The stimulus arouses the taste cell, and this in turn
arouses the ending of the sensory axon that twines about the base of
the cell at the back of the chamber. The taste cell, or its tip, is
extra sensitive to chemical stimuli, and its activity, aroused by the
chemical stimulus, in turn arouses the axon and so starts a nerve
current to the brain stem and eventually to the cortex.


[Illustration: Fig. 26.--The olfactory sense cells and their brain
connections. (Figure text: axon to brain cortex, dendrites, synapses in
brain stem, axons of sense cells sense cells in nose.)]


The olfactory cells, located in a little recess in the upper and back
part of the nose, out of the direct air currents going toward the
lungs, are rather similar to the taste cells. They have fine tips
reaching to the surface of the mucous membrane lining the nasal cavity
and exposed to the chemical stimuli of odors. The olfactory cell has
also a long slender branch extending from its base through the bone
into the skull cavity and connecting there with dendrites of nerve
cells. This central branch of the olfactory cell is, in fact, an axon;
and it is peculiar in being an axon growing from a sense cell. This is
the rule in invertebrates, but in vertebrates the sensory axon is
regularly an outgrowth of a {191} nerve cell, and only in the nose do
we find sense cells providing their own sensory nerve.


[Illustration: Fig. 27.--Sense cells and nerve cells of the retina.
Light, reaching the retina from the interior of the eyeball (as shown
in Fig. 28), passes through the nearly transparent retina till stopped
by the pigment layer, and then and there arouses to activity the tips
of the rods and cones. The rods and cones pass the impulse along to
the bipolar cells and these in turn to the optic nerve cells, the
axons of which extend by way of the optic nerve to the thalamus in the
brain. (Figure text:  pigment layer, rods, cones, light, bipolar Cells,
optic Nerve Cells)]


In the eye, the sense cells are the rods and cones of the retina.
These are highly sensitive to light, or, it may be, to chemical or
electrical stimuli generated in the pigment of the retina by the
action of light. The rods are less highly developed than the cones.
Both rods and cones connect at their base with neurones that pass the
activity along through the optic nerve to the brain.

The internal ear contains sense cells of three rather similar kinds,
all being "hair cells", Instead of a single {192} sensitive tip, each
cell has a number of fine hair-tips, and it is these that first
respond to the physical stimulus. In the cochlea, the part of the
inner ear concerned with hearing, the hairs are shaken by sound
vibrations that have reached the liquid in which the whole end-organ
is immersed. In the "semicircular canals", a part of the inner ear
that is concerned not with sound but with rotary movements of the
head, we find hair cells again, their hair-tips being matted together
and so located as to be bent, like reeds growing on the bottom of a
brook, by currents of the liquid filling the canals. In the
"vestibule", the central part of the inner ear, the hair-tips of the
sense cells are matted together, and in the mat are imbedded little
particles of stony matter, called the "otoliths". When the head is
inclined in any direction, these heavy particles sag and bend the
hairs, so stimulating them; and the same result occurs when a sudden
motion up or down or in any direction is given to the head. Around the
base of the sense cells, in any of these parts of the internal ear,
are twined the fine endings of sensory axons, which are excited by the
activity of the sense cells, and pass the activity on to the brain.


Accessory sense-apparatus.

Every sense except the "pain sense" has more or less of this. The
hairs of the skin are accessory to the sense of touch. A touch on a
hair is so easily felt that we often think of the hairs as sensitive;
but really it is the skin that is sensitive, or, rather, it is the
sensory axon terminating around the root of the hair in the skin. The
tongue can be thought of as accessory apparatus serving the sense of
taste, and the breathing apparatus as accessory to the sense of smell,
"tasting" being largely a tongue movement that brings the substance to
the taste cells, and "smelling" of anything being largely a series of
little inspiratory movements that carry the odor-laden air to the
olfactory part of the nasal cavity.

{193}

But it is in the eye and the ear that the highest development of
accessory sense apparatus has taken place. All of the eye except the
retina, and all of the ear except the sense cells and the sensory
axons, are accessory.


[Illustration: Fig. 28.--Horizontal cross section through the right
eyeball. (Figure text: cornea, ciliary muscle, retina, choroid.
sclerotic, Optic Nerve)]


The eye is an optical instrument, like the camera. In fact, it is a
camera, the sensitive plate being the retina, which differs indeed
from the ordinary photographic plate in recovering after an exposure
so as to be ready for another. Comparing the eye with the camera, we
see that the eyeball corresponds to the box, the outer tough coat
{194} of the eyeball (the "sclerotic" coat) taking the place of the
wood or metal of which the box is built, and the deeply pigmented
"choroid" coat, that lines the sclerotic, corresponding to the coating
of paint used to blacken the inside of the camera box and prevent
stray light from getting in and blurring the picture. At the front of
the eye, where light is admitted, the sclerotic is transformed into
the transparent "cornea", and the choroid into the contractile "iris",
with the hole in its center that we call "the pupil of the eye".


[Illustration: Fig. 29.--Diagram to show the course of the sound waves
through the outer and middle ear and into the inner ear. The arrow is
placed within the "meatus," and points in the direction taken by the
sound waves. See text for their further course. (Figure text: cochlea,
vestibule, semicircular canal, ossicles, Eustachian, ear drum)]


The iris corresponds to the adjustable diaphragm of the camera. Just
behind the pupil is the lens of the eye, which also is adjustable by
the action of a little muscle, called the "ciliary muscle". This
muscle corresponds to the focussing mechanism of the camera; by it the
eye is focussed on near or far objects. The eye really {195} has two
lenses, for the cornea acts as a lens, but is not adjustable. The
"aqueous and vitreous humors" fill the eyeball and keep it in shape,
while still, being transparent, they allow the light to pass through
them on the way to the retina. The retina is a thin coat, lying inside
the choroid at the back of the eyeball, and having the form of a
hollow hemisphere. The light, coming through the pupil and traversing
the vitreous humor, strikes the retina from the inside of the eyeball.
Other accessory apparatus of the eye includes the lids, the tear
glands, and the muscles that turn the eyeball in any direction.


[Illustration: Fig. 30.--Two views of the internal ear. These views
show the shape of the internal ear cavity. The sense organs lie inside
this cavity. Notice how the three semi-circular canals lie in three
perpendicular planes. (Figure text: cochlea, vestibule, 3 Canals)]


The ear is about as complex a piece of mechanism as the eye. We speak
of the "outer", "middle" and "inner" ear. The outer, in such an animal
as the horse, serves as a movable ear trumpet, catching the sound
waves and concentrating them upon the ear drum, or middle ear. The
human external ear seems to accomplish little; it can be cut off
without noticeably affecting hearing. The most essential part of the
external ear is the "meatus" or hole that allows the sound waves to
pass through the skin to the tympanic membrane or drum head. The sound
waves throw this membrane into vibration, and the vibration is
transmitted, by an assembly of three little bones, across the
air-filled cavity {196} of the middle ear to an opening leading to the
water-filled cavity of the inner ear. This opening from the middle to
the inner ear is closed by a membrane in which one end of the assembly
of little bones is imbedded, as the other end is imbedded in the
tympanic membrane; and thus the vibrations are transmitted from the
tympanic membrane to the liquid of the inner ear. Once started in this
liquid, the vibrations are propagated through it to the sense cells of
the cochlea and stimulate them in the way already suggested.


[Illustration: Fig. 31.--A small sample of the sense cells of the
cochlea. The hairs of the sense cells are shaken by the vibration of
the water, and pass the impulse back to the end-brushes of the
auditory axons, The tectorial membrane looks as if it might act as a
damper, but may be concerned, as "accessory apparatus," in the
stimulation of the hair cells. The basilar membrane consists in part
of fibers extending across between the ledges of bone; these fibers
are arranged somewhat after the manner of piano strings, and have
suggested the "piano theory" of hearing, to be mentioned later in the
chapter. (Figure text: water space, membrane, Tectorial membrane, bone,
soft tissue, basilar membrane, auditory axons to brain stem, nerve
cells of auditory nerves, auditory hair cells with end brushes of
auditory axons)]


Further study of the accessory apparatus of the eye and ear can be
recommended as very interesting, but the little that has been said
will serve as an introduction to the study of sensation.


{197}

Analysis of Sensations

Prominent among the psychological problems regarding sensation is that
of analysis. Probably each sense gives comparatively few elementary
sensations, and many blends or compounds of these elements. To
identify the elements is by no means a simple task, for under ordinary
circumstances what we get is a compound, and it is only by carefully
controlling the stimulus that we are able to get the elements before
us; and even then the question whether these are really elementary
sensations can scarcely be settled by direct observation.

Along with the search for elementary sensations goes identification of
the stimuli that arouse them, and also a study of the sensations
aroused by any combination of stimuli. Our task now will be to ask
these questions regarding each of the senses.


The Skin Senses

Rough and smooth, hard and soft, moist and dry, hot and cold, itching,
tickling, pricking, stinging, aching are skin sensations; but some of
these are almost certainly compounds. The most successful way of
isolating the elements out of these compounds is to explore the skin,
point by point, with weak stimuli of different kinds. If a blunt metal
point, or the point of a lead pencil, a few degrees cooler than the
skin, is passed slowly over the skin, at most points no sensation
except that of contact arises, but at certain points there is a clear
sensation of cold. Within an area an inch square on the back of the
hand, several of these _cold spots_ can be found; and when the
exploration is carefully made, and the cold spots marked, they will be
found to give the same sensation every time. Substitute a metal point
a few {198} degrees warmer than the skin, and a few spots will be
found that give the sensation of warmth, these being the _warmth
spots_. Use a sharp point, like that of a needle or of a sharp
bristle, pressing it moderately against the skin, and you get at most
points simply the sensation of contact, but at quite a number of
points a small, sharp pain sensation arises. These are the _pain
spots_. Finally, if the skin is explored with a hair of proper length
and thickness, no sensation at all will be felt at most points,
because the hair bends so readily when one end of it is pressed
against the skin as not to exert sufficient force to arouse a
sensation; but a number of points are found where a definite sensation
of touch or contact is felt; these are the _touch spots_.

No other varieties of "spots" are found, and the four sensations of
touch, warmth, cold and pain are believed to be the only elementary
skin sensations. Itch, stinging and aching seem to be the same as
pain. Tickle is touch, usually light touch or a succession of light
touches. Smooth and rough are successions of touch sensations. Moist
is usually a compound of smooth and cold. Hard and soft combine touch
and the muscular sensation of resistance.

Hot and cold require more discussion. The elementary sensations are
warmth and coolness, rather than hot and cold. Hot and cold are
painful, and the fact is that strong temperature stimuli arouse the
pain spots as well as the warmth or cold spots. Hot, accordingly, is a
sensation compounded of warmth and pain, and cold a sensation composed
of coolness and pain. More than this, when a cold spot is touched with
a point heated well above the skin temperature (best to a little over
100 Fahrenheit), the curious fact is noted that the cold spot responds
with its normal sensation of cold. This is called the "paradoxical
cold sensation". From this fact it is probable that a hot object
excites the cold sensation, along with those of warmth and {199} pain;
so that the sensation of heat is a blend of the three. Another curious
fact is that a very cold object produces a burning sensation
indistinguishable from that of a hot object; so that the sensation of
great cold, like that of heat, is probably a blend of the three
elementary sensations of warmth, cold and pain.


  [Illustration: Fig. 32.--Diagram of various sorts of sensory
  end-organ found in the skin.

  A is a hair end-organ; the sensory axons can be seen coiling around
  the root of the hair; evidently a touch on the hair, outside, would
  squeeze the coiled axon and stimulate it. The hair is a bit of
  "accessory apparatus."

  B is a touch corpuscle, consisting of a coiled axon-end surrounded
  by a little cone of other tissue.

  C is an end-bulb, presumably belonging to the temperature sense. It
  has, again, a coiled axon-end surrounded by other tissue. The
  "coils" are really much more finely branched than the diagram shows.

  D is a free-branched nerve end, consisting simply of a branched
  axon, with no accessory apparatus. It is the pain-sense organ.

  E is a corpuscle of a type found in the subcutaneous tissue, as well
  as in more interior parts of the body. It contains an axon-end
  surrounded by a layered capsule.]


The stimulus that arouses the touch sensation is a bending of the
skin. That which arouses warmth or cold is of {200} course a
temperature stimulus, but, strange as it may seem, the exact nature of
the effective stimulus has not been agreed upon. Either it is a
warming or cooling of the skin, or it is the existence of a higher or
lower temperature in the skin than that to which the skin is at the
moment "adapted". This matter will become clearer when we later
discuss adaptation. The stimulus that arouses the pain sensation may
be mechanical (as a needle prick), or thermal (heat or cold), or
chemical (as the drop of acid), or electrical; but in any case it must
be strong enough to injure or nearly to injure the skin. In other
words, the pain sense organ is not highly sensitive, but requires a
fairly strong stimulus; and thus it is fitted to give warning of
stimuli that threaten injury.

Several kinds of sensory end-organ are found in the skin. There is the
"spherical end-bulb", into which a sensory axon penetrates; it is
believed to be the sense organ for cold. There is the rather similar
"cylindrical end-bulb" believed to be the sense organ for warmth.
There is the "touch corpuscle", found in the skin of the palms and
soles, and consisting, like the end-bulbs, of a mass of accessory
cells with a sensory axon ramifying inside it; this is an end-organ
for the sense of touch. There is the hair end-organ, consisting of a
sensory axon coiled about the root of the hair; this, also, is a touch
receptor. Finally, there is the "free-branched nerve end", consisting
simply of the branching of a sensory axon, with no accessory apparatus
whatever; and this is the pain receptor. Perhaps the pain receptor
requires no accessory apparatus because it does not need to be
extremely sensitive.

Now since we find, in the skin, "spots" responsive to four quite
different stimuli, giving four quite different sensations, and
apparently provided with different types of end-organs, it has become
customary to speak of four skin senses in place of the traditional
"sense of touch". We {201} speak of the pain sense, the warmth sense,
the cold sense, and the pressure sense, which last is the sense of
touch proper.


The Sense of Taste

Analysis has been as successful in the sense of taste as in cutaneous
sensation. Ordinarily we speak of an unlimited number of tastes, every
article of food having its own characteristic taste. Now the interior
of the mouth possesses the four skin senses in addition to taste, and
many tastes are in part composed of touch, warmth, cold or pain. A
"biting taste" is a compound of pain with taste proper, and a "smooth
taste" is partly touch. The consistency of the food, soft, tough,
brittle, gummy, also contributes, by way of the muscle sense, to the
total "taste". But in addition to all these sensations from the mouth,
the flavor of the food consists largely of odor. Food in the mouth
stimulates the sense of smell along with that of taste, the odor of
the food reaching the olfactory organ by way of the throat and the
rear passage to the nose. If the nose is held tightly so as to prevent
all circulation of air through it, most of the "tastes" of foods
vanish; coffee and quinine then taste alike, the only _taste_ of each
being bitter, and apple juice cannot be distinguished from onion
juice.

But when the nose is excluded, and when cutaneous and muscular
sensations are deducted, there still remain a few genuine tastes.
These are sweet, sour, bitter and salty--and apparently no more. These
four are the elementary taste sensations, all others being compounds.
The papillae of the tongue, with their little "pits" already spoken
of, correspond to the "spots" of the skin, with this difference,
however, that the papillae do not each give a single sensation. Some
of them give only two, some only three of the four tastes; and the
bitter taste is aroused principally from {202} the back of the tongue,
the sweet from the tip, the sour from the sides, the salty from both
tip and sides.

The stimulus to the sense of taste is something of a chemical nature.
The tasteable substances must be in solution in order to penetrate the
pits and get to the sensitive tips of the taste cells. If the upper
surface of the tongue is first dried, a dry lump of sugar or salt laid
on it gives no sensation of taste until a little saliva has
accumulated and dissolved some of the substance.

Exactly what is the chemical agent that produces a given taste
sensation is a problem of some difficulty. Many different substances
give the sensation of bitter, and the question is, what there is
common to all these substances. The sweet taste is aroused not only by
sugar, but by glycerine, saccharine, and even "sugar of lead" (lead
acetate). The sour taste is aroused by most acids, but not by all, and
also by some substances that are not chemically acids. Thus the
chemistry of taste stimuli involves something not as yet understood.

Though there is this uncertainty regarding the stimulus, on the whole
the sense of taste affords a fine example of success achieved by
experimental methods in the analysis of complex sensations. At the
same time it affords a fine example of the fusion of different
sensations into characteristic _blends_. The numerous "tastes" of
every-day life, though found on analysis to be compounded of taste,
smell, touch, pain, temperature and muscle sensations, have the effect
of units. The taste of lemonade, for example, compounded of sweet,
sour, cold and lemon odor, has the effect of a single characteristic
sensation. It can be analyzed, but it ordinarily appears as a unit.
This is true generally of blends; indeed, what we mean by blending is
that, while the component sensations are still present and can be
found by careful attention, they are not simply present together {203}
but are compounded into a characteristic total. Each elementary
sensation entering into the blend gives up some of its own quality,
as, in the case of lemonade, neither the sweet nor the sour is quite
so distinct and obtrusive as either would be if present alone. The
same is true of the lemon odor, and it is true generally of the odor
components that enter into the "tastes" of food. Were the odor
components in these tastes as clear and distinct as they are when the
same substance is smelled outside the mouth, we could not fail to
notice that the "tastes" were largely composed of odor. The obtrusive
thing about a blend is the total effect, not the elementary sensations
that are blended.


The Sense of Smell

The great variety of odors long resisted every attempt at
psychological analysis, largely because the olfactory end-organ is so
secluded in position. You cannot apply stimuli to separate parts of
it, as you can to the skin or tongue. But, recently, good progress has
been made, [Footnote: By Henning.] by assembling almost all possible
odors, and becoming thoroughly acquainted with them, not as
substances, but simply as odors, and noting their likenesses and
differences. It seems possible now to state that there are _six
elementary odors_, as follows:

1. Spicy, found in pepper, cloves, nutmeg, etc.

2. Flowery, found in heliotrope, etc.

3. Fruity, found in apple, orange oil, vinegar, etc.

4. Resinous, found in turpentine, pine needles, etc.

5. Foul, found in hydrogen sulphide, etc.

6. Scorched, found in tarry substances.

These being the elements, there are many compound odors. The odor of
roasted coffee is a compound of resinous and scorched, peppermint a
compound of fruity and spicy.

{204}

Each elementary odor corresponds to a certain characteristic in the
chemical constitution of the stimulus.

The sense of smell is extremely delicate, responding to very minute
quantities of certain substances diffused in the air. It is extremely
useful in warning us against bad air and bad food. It has also
considerable esthetic value.


Organic Sensation

The term "organic sensation" is used to cover a variety of sensations
from the internal organs, such as hunger, thirst, nausea, suffocation
and less definite bodily sensations that color the emotional tone of
any moment, contributing to "euphoria" and also to disagreeable states
of mind. Hunger is a sensation aroused by the rubbing together of the
stomach walls when the stomach, being ready for food, begins its
churning movements. Careful studies of sensations from the internal
organs reveal astonishingly little of sensation arising there, but
there can be little doubt that the sensations just listed really arise
where they seem to arise, in the interior of the trunk.

Little has been done to determine the elementary sensations in this
field; probably the organic sensations that every one is familiar with
are blends rather than elements.


The Sense of Sight

Of the tremendous number and variety of visual sensations, the great
majority are certainly compounds. Two sorts of compound sensation can
be distinguished here: _blends_ similar to those of taste or smell,
and _patterns_ which scarcely occur among sensations of taste and
smell, though they are found, along with blends, in cutaneous
sensation. Heat, compounded of warmth, cold and pain sensations, is an
{205} excellent example of a blend, while the compound sensation
aroused by touching the skin simultaneously with two points--or three
points, or a ring or square--is to be classed as a pattern. In a
pattern, the component parts are spread out in space or time (or in
both at once), and for that reason are more easily attended to
separately than the elements in a blend. Yet the pattern, like the
blend, has the effect of a unit. A spatial pattern has a
characteristic shape, and a temporal pattern a characteristic course
or movement. A rhythm or a tune is a good example of a temporal
pattern.

Visual sensations are spread out spatially, and thus fall into spatial
patterns. They also are in constant change and motion, and so fall
into temporal patterns, many of which are spatial as well. The visual
sensation aroused, let us say in a young baby, by the light entering
his eye from a human face, is a spatial pattern; the visual sensation
aroused by some one's turning down the light is a pure temporal
pattern; while the sensation from a person seen moving across the room
is a pattern both spatial and temporal. Finding the elements of a
visual pattern would mean finding the smallest possible bits of it,
which would probably be the sensations due to the action of single
rods and cones, just as the smallest bit of a cutaneous sensation
would be due to the exciting of a single touch spot, warmth spot, cold
spot or pain spot.

Analyzing a visual blend is quite a different job. Given the color
pink, for example, let it be required to discover whether this is a
simple sensation or a blend of two or more elementary sensations.
Studying it intently, we see that it can be described as a whitish
red, and if we are willing to accept this analysis as final, we
conclude that pink is a blend of the elementary sensations of white
and red. Of the thousands and thousands of distinguishable hues,
shades {206} and tints, only a few are elements and the rest are color
blends; and our main problem now is to identify the elements. Notice
that we are not seeking for the physical elements of light, nor for
the primary pigments of the painter's art, but for the elementary
_sensations_. Our knowledge of physics and painting, indeed, is likely
to lead us astray. Sensations are our responses to the physical
stimulus, and the psychological question is, what fundamental
responses we make to this class of stimuli.

Suppose, without knowing anything of pigments or of the physics of
light, we got together a collection of bits of color of every shade
and tint, in order to see what we could discover about visual
sensations. Leaving aside the question of elements for the moment, we
might first try to _classify_ the bits of color. We could sort out a
pile of reds, a pile of blues, a pile of browns, a pile of grays,
etc., but the piles would shade off one into another. The salient fact
about colors is the gradual transition from one to another. We can
arrange them in _series_ better than we can classify them. They can be
serially arranged in three different ways, according to brightness or
intensity, according to color-tone, and according to saturation.

The _intensity series runs from light to dark_. We can arrange such a
series composed entirely of reds or blues or any other one color; or
we can arrange the whole collection of bits of color into a single
light-dark series. It is not always easy to decide whether a given
shade of one color is lighter or darker than a given shade of a
different color; but in a rough way, at least, every bit of whatever
color would have its place in the single intensity series. An
intensity series can, of course, be arranged in any other sense as
well as in sight.

The _color-tone series_ is best arranged from a collection consisting
entirely of full or saturated colors. Start the {207} series with any
color and put next to this the color that most resembles it in
color-tone, i.e., in specific color quality; and so continue, adding
always the color that most resembles the one preceding. If we started
with red, the next in order might be either a yellowish red or a
bluish red. If we took the yellowish red and placed it beside the red,
then the next in order would be a still more yellowish red, and the
series would run on to yellow and then to greenish yellow, green,
bluish green, blue, violet, purple, purplish red, and so back to red.
The color-tone series returns upon itself. It is a circular series.


[Illustration: Fig. 33.--The color circle. R, Y, G and B, stand for
the colors red, yellow, green and blue. The shaded portion corresponds
to the spectrum or rainbow. Complementary colors (see later) lie
diametrically opposite to each other on the circumference.]


A _saturation series_ runs from full-toned or saturated colors to pale
or dull. Since we can certainly say of a pale blue that it is less
saturated than a vivid red, etc., we could, theoretically, arrange our
whole collection of bits of color in a single saturation series, but
our judgment would be very uncertain at many points. The most
significant saturation series confine themselves to a single
color-tone, {208} and also, as far as possible, to a constant
brightness, and extend from the most vivid color sensation obtainable
with this color-tone and brightness, through a succession of less and
less strongly colored sensations of the same tone and brightness, to a
dead gray of the same brightness. Any such saturation series
terminates in a neutral gray, which is light or dark to match the rest
of the particular saturation series.

White, black and gray, which find no place in the color-tone series,
give an intensity series of their own, running from white through
light gray and darker and darker gray to black, and any gray in this
series may be the zero point in a saturation series of any color-tone.

A three-dimensional diagram of the whole system of visual sensations
can be built up in the following way. Taking all the colors of the
same degree of brightness, we can arrange the most saturated, in the
order of their color-tone, around the circumference of a circle, put a
gray of the same brightness at the center of this circle, and then
arrange a saturation series for each color-tone extending from the
most saturated at the circumference to gray at the center. This would
be a two-dimensional diagram for colors having the same brightness.
For a greater brightness, we could arrange a similar circle and place
it above the first, and for a smaller brightness, a similar circle and
place it below the first, and we could thus build up a pile of
circles, ranging from the greatest brightness at the top to the least
at the bottom. But, as the colors all lose saturation when their
brightness is much increased, and also when it is much decreased, we
should make the circles smaller and smaller toward either the top or
the bottom of the pile, so that our three-dimensional diagram would
finally take the form of a double cone, with the most intense white,
like that of sunlight, at the upper point, with dead black at the
lower point, {209} and with the greatest diameter near the middle
brightness, where the greatest saturations can be obtained. The axis
of the double cone, extending from brightest white to dead black,
would give the series of neutral grays. All the thousands of
distinguishable colors, shades and tints, would find places in this
scheme.


[Illustration: Fig. 34.--The color cone, described in the text.
Instead of a cone, a four-sided pyramid is often used, so as to
emphasize the four main colors, red, yellow, green and blue, which are
then located at the corners of the base of the pyramid. (Figure text:
white, black, R, B, G, Y)]


Simpler Forms of the Color Sense

Not every one gets all these sensations. In _color-blindness_, the
system is reduced to one or two dimensions, instead of three. There
are two principal forms of color-blindness: total, very uncommon; and
red-green blindness, fairly {210} common. The totally color-blind
individual sees only white, black, and the various shades of gray. His
system of visual sensations is reduced to one dimension, corresponding
to the axis of our double cone.

_Red-green blindness_, very uncommon in women, is present in three or
four percent of men. It is not a disease, not curable, not corrected
by training, and not associated with any other defect of the eye, or
of the brain. It is simply a native peculiarity of the color sense.
Careful study shows that the only color sensations of the red-green
blind person are blue and yellow, along with white, black and the
grays. His color circle reduces to a straight line with yellow at one
end and blue at the other. Instead of the color circle, he has a
double saturation series, reaching from saturated yellow through
duller yellows to gray and thence through dull blues to saturated
blue. What appears to the normal eye as red, orange or grass green
appears to him as more or less unsaturated yellow; and what appears to
the normal eye as greenish blue, violet and purple appears to him as
more or less unsaturated blue. His color system can be represented in
two dimensions, one for the double saturation series,
yellow-gray-blue, and the other for the intensity series,
white-gray-black.

Color-blindness, always interesting and not without some practical
importance (since the confusions of the color-blind eye might lead to
mistaking signals in navigation or railroading), takes on additional
significance when we discover the curious fact that _every one is
color-blind_--in certain parts of the retina. The outermost zone of
the retina, corresponding to the margin of the field of view, is
totally color-blind (or very nearly so), and an intermediate zone,
between this and the central area of the retina that sees all the
colors, is red-green blind, and delivers only blue and yellow
sensations, along with white, black and gray. Take {211} a spot of
yellow or blue and move it in from the side of the head into the
margin of the field of view and then on towards the center. When it
first appears in the margin, it simply appears gray, but when it has
come inwards for a certain distance it changes to yellow. If a red or
green spot is moved in similarly, it first appears gray, then takes on
a faint tinge of yellow, and finally, as it approaches the center of
the field of view, appears in its true color. The outer zone gets only
black and white, the intermediate zone gets, in addition to these,
yellow and blue, and the central area adds red and green (and with
them all the colors).


[Illustration: Fig. 35.--Color cones of the retina. F is the fovea, or
central area of clearest vision. (Figure text: all colors, white-black &
yellow-blue, white-black)]


Now as to the question of elements, let us see how far we can go,
keeping still to the sensations, without any reference to the
stimulus. If a collection of bits of color is presented to a class of
students who have not previously studied this matter, with the request
that each select those colors that seem to him elementary and not
blends, there is practically unanimous agreement on three colors, red,
yellow and blue; and there are some votes for green also, but almost
none for orange, violet, purple, brown or any other colors. {212}
except white and black. That white and black are elementary sensations
is made clear by the case of total color-blindness, since in this
condition there are no other visual sensations from which white and
black could be compounded, and these two differ so completely from
each other that it would be impossible to think of white as made up of
black, or black of white. Gray, on the other hand, appears like a
blend of black and white. In the same way, red-green blindness
demonstrates the reality of yellow and blue as elementary sensations,
since neither of them could be reduced to a blend of the other with
white or black; and there are no other colors present in this form of
color vision to serve as possible elements out of which yellow and
blue might be compounded. That white, black, yellow and blue are
elementary sensations is therefore clear from the study of visual
sensations alone; and there are indications that red and green are
also elements.


Visual Sensations as Related to the Stimulus

Thus far, we have said nothing of the stimulus that arouses visual
sensations. Light, the stimulus, is physically a wave motion, its
vibrations succeeding each other at the rate of 500,000000,000000
vibrations, more or less, per second, and moving through space with a
speed of 186,000 miles per second. The "wave-length", or distance from
the crest of one wave to the crest of the next following, is measured
in millionths of a millimeter.

The most important single step ever taken towards a knowledge of the
physics of light, and incidentally towards a knowledge of visual
sensations, was Newton's analysis of white light into the spectrum. He
found that when white light is passed through a prism, it is broken up
into all the colors of the rainbow or spectrum. Sunlight consists of a
{213} mixture of waves of various lengths. At one end of the spectrum
are the long waves (wave-length 760 millionths of a millimeter), at
the other end are the short waves (wavelength 390), and in between are
waves of every intermediate length, arranged in order from the longest
to the shortest. The longest waves give the sensation of red, and the
shortest that of violet, a slightly reddish blue.

Outside the limits of the visible spectrum, however, there are waves
still longer and shorter, incapable of arousing the retina, though the
very long waves, beyond the red, arouse the sensation of warmth from
the skin, and the very short waves, beyond the violet, though arousing
none of the senses, do effect the photographic plate. Newton
distinguished seven colors in the visible spectrum, red, orange,
yellow, green, blue, indigo and violet; but there is nothing specially
scientific about this list, since physically there are not seven but
an unlimited number of wave-lengths included in the spectrum, varying
continuously from the longest at the red end to the shortest at the
violet; while psychologically the number of distinguishable colors in
the spectrum, though not unlimited, is at least much larger than
seven. Between red and orange, for instance, there are quite a number
of distinguishable orange-reds and reddish oranges.

If now we ask what differences in the stimulus give rise to the three
kinds of difference in visual sensation that were spoken of
previously, we find that color-tone depends on the wave-length of the
light, brightness on the energy of the stimulus, i.e., on the
amplitude of the vibration, and saturation on the mixture of long and
short wave-lengths in a complex light-stimulus--the more mixture, the
less saturation.

These are the general correspondences between the light stimulus and
the visual sensation; but the whole relationship is much more complex.
Brightness depends, not only on the energy of the stimulus, but also
on wave-length. The {214} retina is tuned to waves of medium length,
corresponding to the yellow, which arouse much brighter sensation than
long or short waves of the same physical energy. Otherwise put, the
sensitivity of the retina is greatest for medium wavelengths, and
decreases gradually towards the ends of the spectrum, ceasing
altogether, as has been said, at wavelengths of 760 at the red end and
of 390 at the violet end.

Saturation, depending primarily on amount of mixture of different
wave-lengths, depends also on the particular wavelengths acting, and
also on their amplitude. So, the red and blue of the spectrum are more
saturated than the yellow and green; and very bright or very dim
light, however homogeneous, gives a less saturated sensation than a
stimulus of medium strength.


Color Mixing

Color-tone depends on the wave-length, as has been said, but this is
far from the whole truth; the whole truth, indeed, is one of the most
curious and significant facts about color vision. We have said that
each color-tone is the response to a particular wave-length. But any
color-tone can be got without its particular wave-length being present
at all; all that is necessary is that wave-lengths centering about
this particular one shall be present. A mixed light, consisting of two
wave-lengths, the one longer and the other shorter than the particular
wave which when acting alone gives a certain color-tone, will give
that same color-tone. For example, the orange color resulting from the
isolated action of a wave-length of 650 is given also by the combined
action of wave-lengths of 600 and 700, in amounts suitably
proportioned to each other.

A point of experimental technique: in _mixing colored lights_ for the
purpose of studying the resulting sensations, we do not mix painter's
pigments, since the physical {215} conditions then would be far from
simple, but we mix the lights themselves by throwing them together
either into the eye, or upon a white screen. We can also, on account
of a certain lag or hang-over in the response of the retina, mix
lights by rapidly alternating them, and get the same effect as if we
had made them strike the retina simultaneously.

By mixing a red light with a yellow, in varying proportions, all the
color-tones between red and yellow can be got--reddish orange, orange
and yellowish orange. By mixing yellow and green lights, we get all
the greenish yellow and yellowish green color-tones; and by mixing
green and blue lights we get the bluish greens and greenish blues.
Finally, by mixing blue and red lights, in varying proportions, we get
violet, purple and purplish red. Purple has no place in the spectrum,
since it is a sensation which cannot be aroused by the action of any
single wave-length, but only by the mixture of long and short waves.

To get all the color-tones, then, we need not employ all the
wave-lengths, but can get along with only four. In fact, we can get
along with three. Red, green and blue will do the trick. Red and green
lights, combined, would give the yellows; green and blue would give
the greenish blues; and red and blue would give purple and violet.

The sensation of white results--to go back to Newton--from the
combined action of all the wave-lengths. But the stimulus _need_ not
contain _all_ the wave-lengths. Four are enough; the three just
mentioned would be enough. More surprising still, two are enough, if
chosen just right. Mix a pure yellow light with a pure blue, and you
will find that you get the sensation of white--or gray, if the lights
used are not strong.

[Footnote: When you mix blue and yellow _pigments_, each absorbs part
of the wave-lengths of white light, and what is left after this double
absorption may be predominantly green. This is absolutely different
from the addition of blue to yellow light; addition gives white, not
green.]

{216}

Lights, or wave-lengths, which when acting together on the retina give
the sensation of white or gray, are said to be _complementary_.
Speaking somewhat loosely, we sometimes say that two _colors_ are
complementary when they mix to produce white. Strictly, the colors--or
at least the color sensations--are not mixed; for when yellow and blue
lights are mixed, the resulting sensation is by no means a mixture of
blue and yellow sensations, but the sensation of white in which there
is no trace of either blue or yellow. Mixing the stimuli which, acting
separately, give two complementary colors, arouses the colorless
sensation of white.

Blue and yellow, then, are complementary. Suppose we set out to find
the complementary of red. Mixing red and yellow lights gives the
color-tones intermediate between these two; mixing red and green still
gives the intermediate color-tones, but the orange and yellow and
yellowish green so got lack saturation, being whitish or grayish. Now
mix red with bluish green, and this grayishness is accentuated, and if
just the right wave-length of bluish green is used, no trace of orange
or yellow or grass green is obtained, but white or gray. Red and
bluish green are thus complementary. The complement of orange light is
a greenish blue, and that of greenish yellow is violet. The typical
green (grass green) has no single wave-length complementary to it, but
it does give white when mixed with a compound of long and short waves,
which compound by itself gives the sensation of purple; so that we may
speak of green and purple as complementary.


What Are the Elementary Visual Sensations?

Returning now to the question of elementary sensations, which we laid
aside till we had examined the relationship of the sensations to the
stimulus, we need to be on our guard against physics, or at least
against being so much impressed with the physics of light as to forget
that we are concerned with the _response_ of the organism to physical
light--a matter on which physics cannot speak the final word.

{217}

  Fig. 36.--(After Koenig.) The color triangle, a map of the laws of
  color mixture. The spectral colors are arranged in order along the
  heavy solid line, and the purples along the heavy dotted line. The
  numbers give the wave-lengths of different parts of the spectrum.
  Inside the heavy line are located the pale tints of each color,
  merging from every side into white, which is located at the point W.

  Suppose equal amounts of two spectral colors are mixed: to find from
  the diagram the color of the mixture. Locate the two colors on the
  heavy line, draw a straight line between these two points, and the
  middle of this line gives the color-tone and saturation of the
  mixture. For example, mix red and yellow: then the resulting color
  is a saturated reddish yellow. Mix red (760) and green (505): the
  resulting yellow is non-saturated, since the straight line between
  these two points lies inside the figure. If the straight line
  joining two points passes through W, the colors located at the two
  points are complementary.

  Spectral colors are themselves not completely saturated. The way to
  get color sensations of maximum saturation is first to stare at one
  color, so as to fatigue or adapt the eye for that color, and then to
  turn the eye upon the complementary color, which, under these
  conditions, appears fuller and richer than anything otherwise
  obtainable. The corners, R, G, and B, denote colors of maximum
  saturation, and the whole of the triangle outside of the heavy line
  is reserved for super-saturated color sensations.


{end 217; text continues from 216}
{218}

Physics tells us of the stimulus, but we are concerned with the
response. The facts of color-blindness and color mixing show very
clearly that the response does not tally in all respects with the
stimulus. Physics, then, is apt to confuse the student at this point
and lead him astray. Much impressed with the physical discovery that
_white_ light is a mixture of all wave-lengths, he is ready to believe
the sensation of white a mixed sensation. He says, "White is the sum
of all the colors", meaning that the sensation of white is compounded
of the sensations of red, orange, yellow, green, blue and
violet--which is simply not true. No one can pretend to get the
sensations of red or blue in the sensation of white, and the fact of
complementary colors shows that you cannot tell, from the sensation of
white, whether the stimulus consists of yellow and blue, or red and
bluish green, or red, green and blue, or all the wave-lengths, the
response being the same to all these various combinations. Total
color-blindness showed us, when we were discussing this matter before,
that white was an elementary sensation, and nothing that has been said
since changes that conclusion.

Consider _black_, too. Physics says, black is the absence of light;
but this must not be twisted to mean that black is the absence of all
visual sensation. Absence of visual sensation is simply nothing, and
black is far from that. It is a sensation, as positive as any, and
undoubtedly elementary.

From the point of view of physics, there is no reason for considering
any one color more elementary than any other. Every wave-length is
elementary; and if sensation tallied precisely with the stimulus,
every spectral color-tone would be an element. But there are obvious
objections to such a view, such as: (1) there are not nearly as many
{219} distinguishable color-tones as there are wave-lengths; (2)
orange, having a single wave-length, certainly appears to be a blend
as truly as purple, which has no single wave-length; and (3) we cannot
get away from the fact of red-green blindness, in which there are only
two color-tones, _yellow_ and _blue_. In this form of color vision
(which, we must remember, is normal in the intermediate zone of the
retina), there are certainly not as many elementary responses as there
are wave-lengths, but only one response to all the longer waves (the
sensation of yellow), one response to all the shorter waves (the
sensation of blue), one response to the combination of long and short
waves (the sensation of white), and one response to the cessation of
light (the sensation of black). These four are certainly elementary
sensations, and there are probably only a few more.

There must be at least two more, because of the fact that two of the
sure elements, yellow and blue, are complementary. For suppose we try
to get along with one more, as _red_. Then red, blended with yellow,
would give the intervening color-tones, namely, orange with reddish
and yellowish orange; and red blended with blue would give violet and
purple; but yellow and blue would only give white or gray, and there
would be no way of getting green. We must admit _green_ as another
element. The particular red selected would be that of the red end of
the spectrum, if we follow the general vote; and the green would
probably be something very near grass green. We thus arrive at the
conclusion that there are six elementary visual responses or
sensations: white and black, yellow and blue, red and green.

It is a curious fact that some of these elementary sensations blend
with each other, while some refuse to blend. White and black blend to
gray, and either white or black or both together will blend with any
of the four elementary colors or with any possible blend of these
four. Brown, for {220} example, is a grayish orange, that is, a blend
of white, black, red and yellow. Red blends with yellow, yellow with
green, green with blue, and blue with red. But we cannot get yellow
and blue to blend, nor red and green. When we try to get yellow and
blue to blend, by combining their appropriate stimuli, both colors
disappear, and we get simply the colorless sensation of white or gray.
When we try to get red and green to blend, both of them disappear and
we get the sensation of yellow.


Theories of Color Vision

Of the most celebrated theories of color vision, the oldest,
propounded by the physicists Young and Helmholtz, recognized only
three elements, red, green and blue. Yellow they regarded as a blend
of red and green, and white as a blend of all three elements. The
unsatisfactory nature of this theory is obvious. White as a sensation
is certainly not a blend of these three color sensations, but is,
precisely, colorless; and no more is the yellow sensation a blend of
red and green. Moreover, the theory cannot do justice either to total
color-blindness, with its white and black but no colors, or to
red-green blindness, with its yellow but no red or green.

The next prominent theory was that of the physiologist Hering. He did
justice to white and black by accepting them as elements; and to
yellow and blue likewise. The fact that yellow and blue would not
blend he accounted for by supposing them to be antagonistic responses
of the retina; when, therefore, the stimuli for both acted together on
the retina, neither of the two antagonistic responses could occur, and
what did occur was simply the more generic response of white.
Proceeding along this line, he concluded that red and green were also
antagonistic responses; but just here {221} he committed a wholly
unnecessary error, in assuming that if red and green were antagonistic
responses, the combination of their stimuli must give white, just as
with yellow and blue. Accordingly, he was forced to select as his red
and green elementary color-tones two that would be complementary; and
this meant a purplish (i.e., bluish) red, and a bluish green, with the
result that his "elementary" red and green appear to nearly every one
as compounds and not elements. It would really have been just as easy
for Hering to suppose that the red and green responses, antagonizing
each other, left the sensation yellow; and then he could have selected
that red and green which we have concluded above to have the best
claim.

A third theory, propounded by the psychologist, Dr. Christine
Ladd-Franklin, is based on keen criticism of the previous two, and
seems to be harmonious with all the facts. She supposes that the color
sense is now in the third stage of its evolution. In the first stage
the only elements were white and black; the second stage added yellow
and blue; and the third stage red and green. The outer zone of the
retina is still in the first stage, and the intermediate zone in the
second, only the central area having reached the third. In red-green
blind individuals, the central area remains in the second stage, and
in the totally color-blind the whole retina is still in the first
stage.

In the first stage, one response, white, was made to light of whatever
wave-length. In the second stage, this single response divided into
two, one aroused by the long waves and the other by the short. The
response to the long waves was the sensation of yellow, and that to
the short waves the sensation of blue. In the third stage, the yellow
response divided into one for the longest waves, corresponding to the
red, and one for somewhat shorter waves, corresponding to the green.
Now, when we try to get a blend of red and green {222} by combining
red and green lights, we fail because the two responses simply unite
and revert to the more primitive yellow response; and similarly when
we try to get the yellow and blue responses together, they revert to
the more primitive white response out of which they developed.

But, since no one can pretend to _see_ yellow as a reddish green, nor
white as a bluish yellow, it is clear that the just-spoken-of union of
the red and green responses, and of the yellow and blue responses,
must take place _below the level of conscious sensation_. These unions
probably take place within the retina itself. Probably they are purely
chemical unions.


[Illustration: Fig. 37--The Ladd-Franklin theory of the evolution of
the color sense. (Figure text: Stage 1--white, Stage 2--yellow blue,
Stage 3--red green blue)]


The _very first_ response of a rod or cone to light is probably a
purely chemical reaction. Dr. Ladd-Franklin, carrying out her theory,
supposes that a light-sensitive "mother substance" in the rods and
cones is decomposed by the action of light, and gives off cleavage
products which arouse the vital activity of the rods and cones, and
thus start nerve currents coursing towards the brain.

In the "first stage", she supposes, a _single_ big cleavage product,
which we may call W, is split off by the action of {223} light upon
the mother substance, and the vital response to W is the sensation of
white.

In the second stage, the mother substance is capable of giving off two
smaller cleavage products, Y and B. Y is split off by the long waves
of light, and B by the short waves, and the vital response to Y is the
sensation of yellow, that to B the sensation of blue. But suppose
that, chemically, Y + B = W: then, if Y and B are both split off at
the same time in the same cone, they immediately unite into W, and the
resulting sensation is white, and neither yellow nor blue.


[Illustration: Fig. 38.--The cleavage products, in the three stages of
the color sense. The "mother substance" is not represented in the
diagram, but only the cleavage products which, according to the
Ladd-Franklin theory, are the direct stimuli for the color sensations.
(Figure text: 1--white, 2--yellow blue, 3--red green blue)]


Similarly, in the third stage, the mother substance is capable of
giving off _three_ cleavage products, R, G and B; and there are three
corresponding vital responses, the sensations of red, green and blue.
But, chemically, R + G = Y; and therefore, if R and G are split off at
the same time, they unite chemically into Y and give the sensation of
yellow. If R, G and B are all split off at the same time, they unite
chemically as follows: R + G = Y, and Y + B = W; and therefore the
resulting sensation is that of white.

This theory of cleavage products is in good general agreement with
chemical principles, and it does justice to all the facts of color
vision, as detailed in the preceding pages. It should be added that
"for black, the theory supposes that, {224} in the interest of a
continuous field of view, objects which reflect no light at all upon
the retina have correlated with them a definite non-light
sensation--that of black." [Footnote: Quotation from Dr.
Ladd-Franklin.]


Adaptation

Sensory adaptation is a change that occurs in other senses also, but
it is so much more important in the sense of sight than elsewhere that
it may best be considered here. The stimulus continues, the sensation
ceases or diminishes--that is the most striking form of sensory
adaptation. Continued action of the same stimulus puts the sense into
such a condition that it responds differently from at first, and
usually more weakly. It is much like fatigue, but it often is more
positive and beneficial than fatigue.

The sense of smell is very subject to adaptation. On first entering a
room you clearly sense an odor that you can no longer get after
staying there for some time. This adaptation to one odor does not
prevent your sensing quite different odors. Taste shows less
adaptation than smell, but all are familiar with the decline in sweet
sensation that comes with continued eating of sweets.

All of the cutaneous senses except that for pain are much subject to
adaptation. Continued steady pressure gives a sensation that declines
rapidly and after a time ceases altogether. The temperature sense is
usually adapted to the temperature of the skin, which therefore feels
neither warm nor cool. If the temperature of the skin is raised from
its usual level of about 70 degrees Fahrenheit to 80 or 86, this
temperature at first gives the sensation of warmth, but after a time
it gives no temperature sensation at all; the warmth sense has become
adapted to the temperature of 80 degrees; and now a temperature of 70
will give the sensation of cool. {225} Hold one hand in water at 80
and the other in water at 66, and when both have become adapted to
these respective temperatures, plunge them together into water at 70;
and you will find this last to feel cool to the warm-adapted hand and
warm to the cool-adapted. There are limits to this power of
adaptation.

The muscle sense seems to become adapted to any fixed position of a
limb, so that, after the limb has remained motionless for some time,
you cannot tell in what position it is; to find out, you have only to
move it the least bit, which will excite both the muscle sense and the
cutaneous pressure sense. The sense of head rotation is adaptable, in
that a rotation which is keenly sensed at the start ceases to be felt
as it continues; but here it is not the sense cells that become
adapted, but the back flow that ceases, as will soon be explained.

To come now to the sense of sight, we have _light adaptation, dark
adaptation_, and _color adaptation_. Go into a dark room, and at first
all seems black, but by degrees--provided there is a little light
filtering into the room--you begin to see, for your retina is becoming
dark-adapted. Now go out into a bright place, and at first you are
"blinded", but you quickly "get used" to the bright illumination and
see objects much more distinctly than at first; for your eye has now
become light-adapted. Remain for some time in a room illuminated by a
colored light (as the yellowish light of most artificial illuminants),
and by degrees the color sensation bleaches out so that the light
appears nearly white.

Dark adaptation is equivalent to sensitizing the retina for faint
light. Photographic plates can be made of more or less sensitiveness
for use with different illuminations; but the retina automatically
alters its sensitivity to fit the illumination to which it is exposed.


{226}

Rod and Cone Vision

You will notice, in the dark room, that while you see light and shade
and the forms of objects, you do not see colors. The same is true out
of doors at night. In other words, the kind of vision that we have
when the eye is dark-adapted is totally color-blind. Another
significant fact is that the fovea is of little use in very dim light.
These facts are taken to mean that dim-light vision, or _twilight
vision_ as it is sometimes called, is _rod vision_ and not cone
vision; or, in other words, that the rods and not the cones have the
great sensitiveness to faint light in the dark-adapted eye. The cones
perhaps become somewhat dark-adapted, but the rods far outstrip them
in this direction. The fovea has no rods and hence is of little use in
very faint light. The rods have no differential responsiveness to
different wave-lengths, remaining still in the "first stage" in the
development of color vision, and consequently no colors are seen in
faint light.

Rod vision differs then from cone vision in having only one response
to every wave-length, and in adapting itself to much fainter light. No
doubt, also, it is the rods that give to peripheral vision its great
sensitivity to moving objects.



After-Images

After-images, which might better be called after-sensations, occur in
other senses than sight, but nowhere else with such definiteness. The
main fact here is that the response outlasts the stimulus. This is
true of a muscle, and it is true of a sense organ. It takes a little
time to get the muscle, or the sense organ, started, and, once it is
in action, it takes a little time for it to stop. If you direct your
eyes towards the lamp, holding your hand or a book in front of them as
a screen, remove the screen for an {227} instant and then replace it,
you will continue for a short time to see the light after the external
stimulus has been cut off. This "positive after-image" is like the
main sensation, only weaker. There is also a "negative after-image",
best got by looking steadily at a black-and-white or colored figure
for as long as fifteen or twenty seconds, and then directing the eyes
upon a medium gray background. After a moment a sensation develops in
which black takes the place of white and white of black, while for
each color in the original sensation the complementary color now
appears.


[Illustration: Fig. 39.--The visual response outlasts the stimulus.
The progress of time is supposed to be from left to right in the
diagram. After the stimulus ceases, the sensation persists for a time,
at first as a positive after-image, and then as a negative
after-image, a sort of back swing. (Figure text: stimulus, sensory
response)]


This phenomenon of the negative after-image is the same as that of
color adaptation. Exposing the retina for some time to light of a
certain color adapts the retina to that color, bleaches that color
sensation, and, as it were, subtracts that color (or some of it) from
the gray at which the eyes are then directed; and gray (or white)
minus a color gives the complementary color.


Contrast

Contrast is still another effect that occurs in other senses, but most
strikingly in vision. There is considerable in common between the
negative after-image and contrast; indeed, {228} the negative
after-image effect is also called "successive contrast". After looking
at a bright surface, one of medium brightness appears dark, while this
same medium brightness would seem bright after looking at a dark
surface. This is evidently adaptation again, and is exactly parallel
to what was found in regard to the temperature sense. After looking at
any color steadily, the complementary color appears more saturated
than usual; in fact, this is the way to secure the maximum of
saturation in color sensation. These are examples of "successive
contrast".

"Simultaneous contrast" is something new, not covered by adaptation,
but gives the same effects as successive contrast. If you take two
pieces of the same gray paper, and place one on a black background and
the other on white, you will find the piece on the black ground to
look much brighter than the piece on the white ground. Spots of gray
on colored backgrounds are tinged with the complementary colors. The
contrast effect is most marked at the margin adjoining the background,
and grows less away from this margin. Any two adjacent surfaces
produce contrast effects in each other, though we usually do not
notice them any more than we usually notice the after-images that
occur many times in the course of the day.


The Sense of Hearing

Sound, like light, is physically a wave motion, though the sound
vibrations are very different from those of light. They travel 1,100
feet a second, instead of 186,000 miles a second. Their wave-length is
measured in feet instead of in millionths of a millimeter, and their
vibration frequencies are counted in tens, hundreds and thousands per
second, instead of in millions of millions. But sound waves vary among
themselves in the same three ways that we {229} noticed in light
waves: in amplitude, in wave-length (or vibration rate), and in degree
of mixture of different wave-lengths.

Difference of amplitude (or energy) of sound waves produces difference
of loudness in auditory sensation, which thus corresponds to
brightness in visual sensation. Sounds can be arranged in order of
loudness, as visual sensations can be arranged in order of brightness,
both being examples of intensity series such as can be arranged in any
kind of sensation.

Difference of wave-length of sound waves produces difference in the
_pitch_ of auditory sensation, which thus corresponds to color in
visual sensation. Pitch ranges from the lowest notes, produced by the
longest audible waves, to the highest, produced by the shortest
audible waves. It is customary, in the case of sound waves, to speak
of vibration rate instead of wave-length, the two quantities being
inversely proportional to each other (in the same conducting medium).
The lowest audible sound is one of about sixteen vibrations per
second, and the highest one of about 30,000 per second, while the
waves to which the ear is most sensitive have a vibration rate of
about 1,000 to 4,000 per second. The ear begins to lose sensitiveness
as early as the age of thirty, and this loss is most noticeable at the
upper limit, which declines slowly from this age on.

Middle C of the piano (or any instrument) has a vibration rate of
about 260. Go up an octave from this and you double the number of
vibrations per second; go down an octave and you halve the number of
vibrations. Of any two notes that are an octave apart, the upper has
twice the vibration rate of the lower. The whole range of audible
notes, from 16 to 30,000 vibrations, thus amounts to about eleven
octaves, of which music employs about eight octaves, finding little
use for the upper and lower extremes of the {230} pitch series. The
smallest step on the piano, called the "semitone", is one-twelfth of
an octave; but it must not be supposed that this is the smallest
difference that can be perceived. A large proportion of people can
observe a difference of four vibrations, and keen ears a difference of
less than one vibration; whereas the semitone, at middle C, is a step
of about sixteen vibrations.

_Mixture of different wave-lengths_, which in light causes difference
of saturation, may be said in sound to cause difference of purity. A
"pure tone" is the sensation aroused by a stimulus consisting wholly
of waves of the same length. Such a stimulus is almost unobtainable,
because every sounding body gives off, along with its fundamental
waves, other waves shorter than the fundamental and arousing tone
sensations of higher pitch, called "overtones". A piano string which,
vibrating as a whole, gives 260 vibrations per second (middle C), also
vibrates at the same time in halves, thus giving 520 vibrations per
second; in thirds, giving 780 per second; and in other smaller
segments. The whole stimulus given off by middle C of the piano is
thus a compound of fundamental and overtones; and the sensation
aroused by this complex stimulus is not a "pure tone" but a blend of
fundamental tone and overtones. By careful attention and training, we
can "hear out" the separate overtones from the total blend; but
ordinarily we take the blend as a unit (just as we take the taste of
lemonade as a unit), and hear it simply as middle C of a particular
quality, namely the piano quality. Another instrument will give a
somewhat different combination of overtones in the stimulus, and that
means a different quality of tone in our sensation. We do not
ordinarily analyze these complex blends, but we distinguish one from
another perfectly well, and thus can tell whether a piano or a cornet
is playing. The difference between different instruments, which we
have spoken of as a {231} difference in quality or purity of tone, is
technically known as _timbre_; and the timbre of an instrument depends
on the admixture of shorter waves with the fundamental vibration which
gives the main pitch of a note.

Akin to the timbre of an instrument is the _vowel_ produced by the
human mouth in any particular position. Each vowel appears to consist,
physically, of certain high notes produced by the resonance of the
mouth cavity. In the position for "ah", the cavity gives a certain
tone; in the position for "ee" it gives a higher tone. Meanwhile, the
pitch of the voice, determined by the vibration of the vocal cords,
may remain the same or vary in any way. The vowel tones differ from
overtones in remaining the same without regard to the pitch of the
fundamental tone that is being sung or spoken, whereas overtones move
up or down along with their fundamental. The vowels, as auditory
sensations, are excellent examples of blends, in that, though
compounds, they usually remain unanalyzed and are taken simply as
units. What has been said of the vowels applies also to the
semi-vowels and continuing consonants, such as l, m, n, r, f, th, s
and sh.

Other consonants are to be classed with the noises. Like a vowel, and
like the timbre of an instrument, a noise is a blend of simple tones;
but the fundamental tone in a noise-blend is not so preponderant as to
give a clear pitch to the total sound, while the other tones present
are often too brief or too unsteady to give a tonal effect.


Comparison of Sight and Hearing

The two senses of sight and hearing have many curious differences, and
one of the most curious appears in mixing different wave-lengths.
Compare the effect of throwing two colored lights together into the
eye with the effect of {232} throwing two notes together into the ear.
Two notes sounded together may give either a harmonious blend or a
discord; now the discord is peculiar to the auditory realm; mixed
colors never clash, though colors seen side by side may do so to a
certain extent. A discord of tones is characterized by imperfect
blending (something unknown in color mixing), and by roughness due to
the presence of "beats" (another thing unknown in the sense of sight).
Beats are caused by the interference between sound waves of slightly
different vibration rate. If you tune two whistles one vibration apart
and sound them together, you get a tone that swells once a second;
tune them ten vibrations apart and you get ten swellings or beats per
second, and the effect is rough and disagreeable.

Aside from discord, a tone blend is really not such a different sort
of thing from a color blend. A chord, in which the component notes
blend while they can still, by attention and training, be "heard out
of the chord", is quite analogous with such color blends as orange,
purple or bluish green. At the same time, there is a curious
difference here. By analogy with color mixing, you would expect two
notes, as C and E, when combined, to give the same sensation as the
single intermediate note D. Nothing of the kind! Were it so, music
would be very different from what it is, if indeed it were possible at
all. But the real difference between the two senses at this point is
better expressed by saying that D does not give the effect of a
combination of C and E, or, in general, that no one note ever gives
the effect of a combination or blend of notes higher and lower than
itself. Homogeneous orange light gives the sensation of a blend of red
and yellow; but there is nothing like this in the auditory sphere. In
light, some wave-lengths give the effect of simple colors, as red and
yellow; and other wave-lengths the effect of blends, as greenish
yellow or bluish {233} green; but in sound, every wave-length gives a
tone which seems just as elementary as any other.

There is nothing in auditory sensation to correspond to white, no
simple sensation resulting from the combined action of all
wave-lengths. Such a combination gives noise, but nothing that seems
particularly simple. There is nothing auditory to correspond with
black, for silence seems to be a genuine absence of sensation. There
are no complementary tones like the complementary colors, no tones
that destroy each other instead of blending. In a word, auditory
sensation tallies with its stimulus much more closely than visual
sensation does with its; and the main secret of this advantage of the
sense of hearing is that it has a much larger number of elementary
responses. Against the six elementary visual sensations are to be set
auditory elements to the number of hundreds or thousands. From the
fact that every distinguishable pitch gives a tone which seems as
simple and unblended as any other, the conclusion would seem to be
that each was an element; and this would mean thousands of elements.
On the other hand, the fact that tones close together in pitch sound
almost alike may mean that they have elements in common and are thus
themselves compounds; but still there would undoubtedly be hundreds of
elements.

Both sight and hearing are served by great armies of sense cells, but
the two armies are organized on very different principles. In the
retina, the sense cells are spread out in such a way that each is
affected by light from one particular direction; and thus the retina
gives excellent space information. But each retinal cell is affected
by any light that happens to come from its particular direction. Every
cone, in the central area of the retina, makes all the elementary
visual responses and gives all the possible color sensations; so it is
not strange that the number of visual {234} elements is small. On the
other hand, the ear, having no sound lens, has no way of keeping
separate the sounds from different directions (and accordingly gives
only meager indications of the direction of sound); but its sense
cells are so spread out as to be affected, some by sound of one
wavelength, others by other wave-lengths. The different tones do not
all come from the same sense cells. Some of the auditory cells give
the low tones, others the medium tones, still others the high tones;
and since there are thousands of cells, there may be thousands of
elementary responses.


Theory of Hearing

The most famous theory of the action of the inner ear is the "piano
theory" of Helmholtz. The foundation of the theory is the fact that
the sense cells of the cochlea stand on the "basilar membrane", a
long, narrow membrane, stretched between bony attachments at either
side, and composed partly of fibers running crosswise, very much as
the strings of a piano or harp are stretched between two side bars. If
you imagine the strings of a piano to be the warp of a fabric and
interwoven with crossing fibers, you have a fair idea of the structure
of the basilar membrane, except for the fact that the "strings" of the
basilar membrane do not differ in length anywhere like as much as the
strings of the piano must differ in order to produce the whole range
of notes. Now, a piano string can be thrown into "sympathetic
vibration", as when you put on the "loud pedal" (remove the dampers
from the strings) and then sing a note into the piano. You will find
that the string of the pitch sung has been thrown into vibration by
the action of the sound waves sung against it.

Now suppose the strings of the basilar membrane to be tuned to notes
of all different pitches, within the range of {235} audible
vibrations: then each string would be thrown into sympathetic
vibration whenever waves of its own vibration rate reached it by way
of the outer and middle ear; and the sense cells standing over the
vibrating fibers would be shaken and excited. The theory is very
attractive because it would account so nicely for the great number of
elementary tone sensations (there are over 20,000 fibers or strings in
the basilar membrane), as well as for various other facts of
hearing--if we could only believe that the basilar membrane did
vibrate in this simple manner, fiber by fiber. But (1) the fabric into
which the strings of the membrane are woven would prevent their
vibrating as freely and independently as the theory requires; (2) the
strings do not differ in length a hundredth part of what they would
need to differ in order to be tuned to all notes from the lowest to
the highest, and there is no sign of differences in stretch or in
loading of the strings to make up for their lack of difference in
length; and (3) a little model of the basilar membrane, exposed to
sound waves, is seen to be thrown into vibration, indeed, and into
different forms of vibration for waves of different length, but not by
any means into the simple sort of vibration demanded by the piano
theory. This theory is accordingly too simple, but it probably points
the way towards some truer, more complex, conception.

The fact that there are many elementary sensations of hearing is the
chief reason why the art of tones is so much more elaborate than the
art of color; for while painting might dispute with music as to which
were the more highly developed art, painting depends on form as well
as color, and there is no art of pure color at all comparable with
music, which makes use simply of tones (and noises) with their
combinations and sequences.

{236}

Senses of Bodily Movement

It is a remarkable fact that some parts of the inner ear are not
connected with hearing at all, but with quite another sense, the
existence of which was formerly unsuspected. The two groups of sense
cells in the vestibule--the otolith organs--were formerly supposed to
be the sense organ for noise; but noise now appears to be a compound
of tones, and its organ, therefore, the cochlea. The _semicircular
canals_, from their arrangement in three planes at right angles to
each other, were once supposed to analyze the sound according to the
direction from which it came; but no one could give anything but the
vaguest idea of how they might do this, and besides the ear is now
known to give practically no information regarding the direction of
sound, except the one fact whether it comes from the right or left,
which is given by the difference in the stimulation received by the
two ears, and not by anything that exists in either ear taken alone.

The semicircular canals have been much studied by the physiologists.
They found that injury to these structures brought lack of equilibrium
and inability to walk, swim or fly in a straight course. If, for
example, the horizontal canal in the left ear is destroyed, the animal
continually deviates to the left as he advances, and so is forced into
a "circus movement". They found that the compensatory movements
normally made in reaction to a movement impressed on the animal from
without were no longer made when the canals were destroyed. They found
that something very much like these compensatory movements could be
elicited by direct stimulation of the end-organs in the canals or of
the sensory nerves leading from them. And they found that little
currents of the liquid filling the canals acted as a stimulus to these
end-organs and so aroused the {237} compensatory movements. They were
thus led to accept a view that was originally suggested by the
position of the canals in space.


[Illustration: Fig. 40.--How the sense cells in a semicircular canal
are stimulated by a water current. This current is itself an inertia
back-flow, resulting from a turning of the head in the opposite
direction. (Figure text: water current, nerve to brain)]


Each "semicircular" canal, itself considerably more than a
semicircular tube, opens into the vestibule at each end and thus
amounts to a complete circle. Therefore rotating the head must, by
inertia, produce a back flow of the fluid contents of the canal, and
this current, by bending the hairs of the sense cells in the canal,
would stimulate them and give a sensation of rotation, or at least a
sensory nerve impulse excited by the head rotation.

When a human subject is placed, blindfolded, in a chair that can be
rotated without sound or jar, it is found that he can easily tell
whenever you start to turn him in either direction. If you keep on
turning him at a constant speed, he soon ceases to sense the movement,
but if then you stop him, he says you are starting to turn him in the
opposite {238} direction. He senses the beginning of the rotary
movement because this causes the back flow through his canals; he
ceases to sense the uniform movement because friction of the liquid in
the slender canal soon abolishes the back flow by causing the liquid
to move with the canal; and he senses the stopping of this movement
because the liquid, again by inertia, continues to move in the
direction it had been moving just before when it was keeping pace with
the canal. Thus we see that there are conscious sensations of rotation
from the canals, and that these give information of the starting or
stopping of a rotation, though not of its steady continuance.
Excessive stimulation of the canals gives the sensation of dizziness.

The otolith organs in the vestibule are probably excited, not by
rotary movements, but by sudden startings and stoppings of rectilinear
motion, as in an elevator; and also by the pull of gravity when the
head is held in any position. They give information regarding the
position and rectilinear movements of the head, as the canals do of
rotary head movements. Both are important in maintaining equilibrium
and motor efficiency.

The muscle sense is another sense of bodily movement; it was the
"sixth sense", so bitterly fought in the middle of the last century by
those who maintained that the five senses that were enough for our
fathers ought to be enough for us, too. The question was whether the
sense of touch did not account for all sensations of bodily movement.
It was shown that there must be something besides the skin sense,
because weights were better distinguished when "hefted" in the hand
than when simply laid in the motionless palm; and it was shown that
loss of skin sensation in an arm or leg interfered much less with the
cooerdinated movements of the limb than did the loss of all the sensory
nerves to the limb.


  [Illustration: Fig. 41.--(From Cajal.) A "tendon spindle," very
  similar to the muscle spindle spoken of in the text, but found at
  the tendinous end of a muscle instead of embedded in the muscle
  substance itself, "a" indicates the tendon, and "e" the muscle
  fibers; "b" is a sensory axon, and "c" its end-brush about the
  spindle. Let the tendon become taut in muscular contraction, and the
  fine branches of the sensory axon will be squeezed and so
  stimulated.]


Later, the crucial fact was established {239} that sense organs (the
"muscle spindles") existed in the muscles and were connected with
sensory nerve fibers; and that other sense organs existed in the
tendons and about {240} the joints. This sense accordingly might
better be called the "muscle, tendon and joint sense", but the shorter
term, "muscle sense", bids fair to stick. The Greek derivative,
"kinesthesis", meaning "sense of movement", is sometimes used as an
equivalent; and the corresponding adjective, "kinesthetic", is common.

The muscle sense informs us of movements of the joints and of
positions of the limbs, as well as of resistance encountered by any
movement. Muscular fatigue and soreness are sensed through the same
general system of sense organs. This sense is very important in the
control of movement, both reflex and voluntary movement. Without it, a
person lacks information of where a limb is to start with, and
naturally cannot know what movement to make; or, if a movement is in
process of being executed, he has no information as to how far the
movement has progressed and cannot tell when to stop it. Thus it is
less strange than it first appears to learn that "locomotor ataxia", a
disease which shows itself in poor control of movement, is primarily a
disease affecting not the motor nerves but the sensory nerves that
take care of the muscle sense.

{241}

EXERCISES

1. Outline the chapter, rearranging the material somewhat, so as to
   state, under each sense, (a) what sense cells, if any, are present
   in the sense organ, (b) what accessory apparatus is present in the
   sense organ, (c) what stimuli arouse the sense, (d) what are the
   elementary responses of the sense, (e) peculiar blends occurring
   within the sense or between this sense and another, (f) what can be
   said regarding adaptation of the sense, and (g) what can be said
   regarding after-images of the sense.

2. Classify the senses according as they respond to stimuli
   (a) internal to the body, (b) directly affecting the surface of the
   body, (c) coming from a distance.

3. What distinctive _uses_ are made of each sense?

4. Explore a small portion of the skin, as on the back of the hand,
   for cold spots, and for pain spots.

5. Try to analyze the smooth sensation obtained by laying the
   finger tip on a sheet of paper, and the rough sensation obtained by
   laying the finger tip on the surface of a brush, and to describe
   the difference in terms of the elementary skin sensations.

6. Is the pain sense a highly developed sense, to judge from its
   sense organ? Is it highly specialized? highly sensitive? How does
   its peculiarity in these respects fit it for its use?

7. Separation of taste and smell. Compare the taste of foods when
   the nostrils are held closed with the taste of the same food when
   the nostrils are opened.

8. Make a complete analysis of the sensations obtained from chocolate
   ice cream in the mouth.

9. Peripheral vision. (a) Color sense. While your eyes are looking
   rigidly straight ahead, take a bit of color in the hand and bring
   it slowly in from the side, noticing what color sensation you get
   from it when it can first be seen at all, and what changes in color
   appear as it moves from the extreme periphery to the center of the
   field of view, (b) Form sense. Use printed letters in the same way,
   noticing how far out they can be read, (c) Sense of motion. Notice
   how far out a little movement of the finger can be seen. Sum up
   what you have learned of the differences between central and
   peripheral vision. What is the use of peripheral vision?

10. Light and dark adaptation. Go from a dimly lighted place
    into bright sunlight, and immediately try for an instant to read
    with the sun shining directly upon the page. Remaining in the
    sunlight, {242} repeat the attempt every 10 seconds, and notice
    how long it takes for the eye to become adapted to the bright
    light. Having become light-adapted, go back into a dimly lighted
    room, and see whether dark-adaptation takes more or less time than
    light-adaptation.

11. Color adaptation. Look steadily at a colored surface, and notice
    whether the color fades as the exposure continues. Try looking at
    the color with one eye only, and after a minute look at the color
    with each eye separately, and notice whether the saturation
    appears the same to the eye that has been exposed to the color,
    and to the eye that has been shielded.

12. Negative after-images. Look steadily for half a minute at a
    black cross upon a white surface, and then turn the eyes upon a
    plain gray surface, and describe what you see. (b) Look steadily
    for half a minute at a colored spot upon a white or gray
    background, and then turn the eyes upon a gray background, and
    note the color of the after-image of the spot. Repeat with a
    different color, and try to reach a general statement as to the
    color of the negative after-image.

13. Positive visual after-images. Look in the direction of a bright
    light, such as an electric light, holding the hand as a screen
    before the eyes, so that you do not see the light. Withdraw the
    hand for a second, exposing the eyes to the light, and immediately
    screen the eyes again, and notice whether the sensation of the
    light outlasts the stimulus.

14. Tactile after-images. Touch the skin lightly for an instant,
    and notice whether the sensation ends as soon as the stimulus is
    removed. If there is any after-image, is it positive or negative?

15. Tactile adaptation. Support two fingers on the edge of a table,
    and lay on them a match or some other light object. Let this
    stimulus remain there, motionless, and notice whether the tactile
    sensation remains steady or dies out. What is the effect of making
    slight movements of the fingers, and so causing the stimulus to
    affect fresh parts of the skin?

16. Temperature sense adaptation. Have three bowls of water, one
    quite warm, one cold, one medium. After holding one hand in the
    warm water and the other in the cold, transfer both simultaneously
    to the medium water and compare the temperature sensations got by
    each hand from this water. State the result in terms of
    adaptation.

17. Overtones. These can be quite easily heard in the sound of a
    large bell. What use does the sense of hearing make of overtones?



REFERENCES
For a somewhat fuller discussion of the topic of sensation, see
Warren's _Human Psychology_, 1919, pp. 151-214; and for a much fuller
discussion, see Titchener's _Textbook of Psychology_, 1909, pp.
46-224.

{243}

For a really thorough consideration of the facts and theories of color
vision, see J. Herbert Parsons, _An Introduction to the Study of
Colour Vision_, 1915.

For a more complete statement of the Ladd-Franklin theory, see the
article on "Vision", in Baldwin's _Dictionary of Philosophy and
Psychology_, 1902.

For a recent study that has revolutionized the psychology of the sense
of smell, see _Der Geruch_, by Hans Henning, 1916, or a review of the
same by Professor Gamble in the _American Journal of Psychology_,
1921, Vol. 32, pp. 290-296.

For an extensive discussion of the "Psychology of Sound", sec the book
with this title by Henry J. Watt, 1917.

For a full account of taste, see Hollingworth and Poffenberger's
_Sense of Taste_, 1917.


{244}


CHAPTER XI

ATTENTION

HOW WE ATTEND, TO WHAT, AND WITH WHAT RESULTS

"Attention!" shouts the officer as a preliminary to some more specific
command, and the athletic starter calls out "Ready!" for the same
purpose. Both commands are designed to put the hearer in an attitude
of readiness for what is coming next. They put a stop to miscellaneous
doings and clear the way for the specific reaction that is next to be
called for. They nullify the effect of miscellaneous stimuli that are
always competing for the hearer's attention, and make him responsive
only to stimuli coming from the officer. They make the hearer clearly
conscious of the officer. They arouse in the hearer a condition of
keen alertness that cannot be maintained for more than a few seconds
unless some further command comes from the officer. In all these ways
"attention" in the military sense, or "readiness" in the athletic
sense, affords a good picture of the psychology of attention.
Attention is preparatory, selective, mobile, highly conscious. To
attend to a thing is to be keenly conscious of that thing, it is to
respond to that thing and disregard other things, and it is to expect
something more from that thing.

Attention is, in a word, exploratory. To attend is to explore, or to
start to explore. Primitive attention amounts to the same as the
instinct of exploration. Its natural stimulus is anything novel or
sudden, its "emotional state" is curiosity or expectancy, and its
instinctive reaction consists {245} of exploratory movements. Its
inherent impulse is to explore, examine, or await.

Attention belongs fundamentally among the native forms of behavior.
The child does not have to learn to attend, though he must learn to
attend to many things that do not naturally get his attention. Some
stimuli naturally attract attention, and others attract attention only
because of previous experience and training. In considering the whole
subject of attention, then, we shall in part be dealing with native
responses, and in part with responses that are acquired. But the great
laws of attention, which will come to light in the course of the
chapter, are at the same time general laws of reaction, and belong
under the head of native characteristics.


The Stimulus, or What Attracts Attention

We can attend to anything whatever, but are more likely to attend to
some things than to others. As stimuli for attention, some objects are
much more effective than others, and the question is, in what way one
object has the advantage over another. There are several ways, several
"factors of advantage", we may call them.

_Change_ is the greatest factor of advantage. A steady noise ceases
after a while to be noticed, but let it change in any respect and
immediately it arrests attention. The ticking of the clock is a good
example: as long as it keeps uniformly on, it is unnoticed, but if it
should suddenly beat faster or louder or in a different key, or even
if it should stop altogether, it would "wake us up" with a start. The
change in the stimulus must not be too gradual if it is to be
effective, it must have a certain degree of suddenness. It may be a
change in intensity, a becoming suddenly stronger or weaker; or it may
be change in quality, as in tone, or {246} color, or odor; or it may
be a change in position, a movement in space. When one who is holding
our arm gives it a sudden squeeze to attract our attention, that is a
change of intensity; when we step from the bank into the water, the
sudden change from warmth to cold, that gets our attention without
fail, is a change of quality; and something crawling on the skin
attracts attention by virtue of its motion. Anything moving in the
field of view is also an unfailing stimulus to attention.

_Strength_, or high intensity of a stimulus, is another important
factor of advantage. Other things being equal, a strong stimulus will
attract attention before a weak one. A loud noise has the advantage
over a low murmur, and a bright flash of light over a faint twinkle.

In the case of visible objects, size has about the same effect as
intensity. The large features of the landscape are noticed before the
little details. The advertiser uses large type, and pays for big space
in the newspaper, in the effort to attract the attention of the
reader.

  [Footnote: Often he pays more than the space is worth; at least
  doubling the size of his "ad" will not, on the whole, double the
  amount of attention he gets, or the number of readers whose
  attention he will catch. The "attention value" of an advertisement
  has been found by Strong to increase, not as fast as the increase in
  space, but about as the square root of the space occupied.]

Another similar factor is _repetition_. Cover a billboard with several
copies of the same picture, and it attracts more attention than a
single one of the pictures would. Repeat a "motive" in the decoration
of a building, and it is more likely to be noticed. Repeat a cry or
call several times, and after a while it may be noticed, though not at
first. The "summation of stimuli" has much the same effect as
increasing the intensity of a single stimulus.

If, however, a stimulus is repeated or continued for a long time, it
will probably cease to hold attention, because of its {247} monotony,
or, in other words, because it lacks the element of change.

_Striking quality_ is an advantage, quite apart from the matter of
intensity. Saturated colors, though no stronger in intensity of light
than pale colors, are stronger stimuli for attention. High notes are
more striking than low. Itch, tickle and pain get attention in
preference to smooth touch. "Striking" cannot be defined in physical
terms, but simply refers to the fact that some kinds of stimulus get
attention better than others.

_Definite form_ has the advantage over what is vague. A small, sharply
defined object, that stands out from its background, attracts the eye
more than a broad, indefinite expanse of light such as the sky. In the
realm of sound, "form" is represented by rhythm or tune, and by other
definite sequences of sound, such as occur in the jingles that catch
the little child's ear.

The factors of advantage so far mentioned are native, and a stimulus
possessing one or more of them is a natural attention-stimulus. But
the individual also learns what is worth noticing, and what is not,
and thus forms _habits of attention_, as well as habits of
inattention. The automobile driver forms the habit of attending to the
sound of his motor, the botanist forms the habit of noticing such
inconspicuous objects as the lichens on the tree trunks. On the other
hand, any one forms the habit of not noticing repeated stimuli that
have no importance for him. Move into a house next the railroad, and
at first you notice every train that passes; even at night you awake
with a start, dreaming that some monster is pursuing you; but after a
few days the trains disturb you very little, night or day. The general
rule covering attention habits is this: anything that you have to work
with, or like to play with, acquires the power to attract your
attention, while anything that you do nothing {248} with loses
whatever hold on your attention it may have possessed by virtue of its
intensity, quality, etc.

Besides these permanent habits of attention, there are temporary
adjustments determined by the _momentary interest_ or desire. Stimuli
relevant to the momentary interest have an unwonted hold upon
attention, while things out of line with this interest may escape
attention altogether, even though the same things would ordinarily be
noticed. What you shall notice in the store window is governed by what
you are looking for as much as by the prominence of the object in the
total display. When you are angry with a person, you notice bad points
about him that you usually overlook, and any aroused desire adjusts or
"sets" attention in a similar way. The desire or interest of the
moment _facilitates_ attention to certain stimuli and _inhibits_
attention to others, and is thus an important factor of advantage.

The interest of the moment is often represented by a question. Ask
yourself what spots of red there are in the field of view, and
immediately various red spots jump out and strike the eye; ask
yourself what pressure sensations you are getting from the skin, and
immediately several obtrude themselves. A question sets attention
towards whatever may furnish an answer.

To sum up, we may say that three general factors of advantage
determine the power of any stimulus to attract attention. There is the
native factor, consisting of change, intensity, striking quality, and
definite form; there is the factor of habit, dependent on past
experience; and there is the factor of present interest and desire.


The Motor Reaction in Attention

Attention is obviously a reaction of the individual to the stimulus
that gets his attention; and it is in part a motor {249} reaction. The
movements that occur in attending to an object are such as to afford a
better view of it, or a better hearing of it, or, in general, such as
to bring the sense organs to bear on it as efficiently as possible.

We may distinguish two sorts of motor reaction that occur in
attention: the general attentive attitude, and the special adjustments
of the sense organs. An audience absorbed in a speech or musical
performance gives a good picture of the general _attentive attitude_.
You notice that most people look fixedly towards the speaker, as if
listening with their eyes, and that many of them lean forward as if it
were important to get just as close as possible. All the little
restless movements cease, so that you could "hear a pin drop", and at
the tensest moments even the breath is checked. The attitude of
attention is one of tense immobility, with the whole body oriented
towards the object of attention. When the object of attention is
something not present but thought of, a somewhat similar rigid
attitude is assumed; the body is apt to lean forward, the neck to be
held stiff, and the eyes to "stare at vacancy", i.e., to be fixed on
some convenient object as a mere resting place, while attention is
fixed outside the visual field altogether.

But we spoke of attention as mobile, and it would be strange if its
mobility did not show itself in the motor reaction. It does in fact
show itself in the _sense organ adjustments_ which amount to
exploratory reactions. Attention to an object in the hand is shown by
"feeling of it", to a substance in the mouth by tasting movements, to
an odor by sniffing movements, to a sound by cocking the head and
turning the eyes towards the source of sound. The most instructive of
this type of attention-reactions are those of the eyes. The eye is
focused on the object that arouses attention, the lens being
accommodated for its distance by the action of the little ciliary
muscle inside the {250} eyeball; the two eyes are converged upon the
object, so that the light from it strikes the fovea or best part of
each retina; and the eyes are also turned up, down or sidewise, so as,
again, to receive the light from the object upon the fovea.

This last class of eye movements is specially instructive and shows
specially well the mobility of attention. Let a bright or moving
object appear somewhere in the field of view--immediately the eyes
turn towards it with a quick jump, fixate it for a few seconds and
then jump elsewhere unless the object is found to be specially
significant. Watch the eyes of one who is looking at a picture or
scene of any sort, and you will see his eyes jumping hither and
thither, as his attention shifts from one part of the scene to
another. Ask him to abstain from this jumpy movement and let his eyes
"sweep over" the scene, and he will confidently try to follow your
instructions, but if you watch his eyes you will find them still
jumping. In fact, "sweeping the glance" is a myth. It cannot be done.
At least, there is only one case in which it can be done, and that is
when there is a moving object to look at. Given an object moving at a
moderate speed across the field of view, and the eyes can follow it
and keep pace with it pretty accurately. But without the moving object
as stimulus, the eyes can only execute the jump movement. There are
thus two types of exploratory eye movement: the "jump" in passing from
one object to another, and the "pursuit movement" in examining a
moving object.

In reading, the eye moves by a series of short jumps from left to
right along the first line of print, makes a long jump back to the
beginning of the second line and another series of short jumps along
that line, and so on. To appreciate the value of this jerky movement,
we need to understand that each short jump occupies but a thirtieth to
a fiftieth {251} of a second, while the "fixation pauses" between
jumps last much longer, with the result that over ninety per cent. of
the time spent on a line of print is fixation time, and less than ten
per cent, is occupied in jumping from one fixation to the next. Now,
it has been found that nothing of any consequence is seen during the
eye jumps, and that the real seeing takes place only during the
fixations. The jump movement, therefore, is simply a means of passing
from one fixation to another with the least possible loss of time.

The eye sees an object distinctly only when at rest with respect to
the object. If the object is still, the eye must be still to see it
distinctly, and to see its different parts must fixate one after the
other, jumping from one part to another. But if the object is in
motion, the eye may still be able to see it distinctly by means of the
pursuit movement, which is a sort of moving fixation.


The Shifting of Attention

Eye movement affords a good picture of the mobility of attention.
Ordinarily the eye shifts frequently from one part of the field of
view to another. When simply exploring a scene, it shifts about in
what seems an indiscriminate way, though really following the
principle of deserting each object as soon as it has been examined,
and jumping to that other object which next has the advantage on
account of movement, brightness, color, definite form, or habit of
attention. In reading, however, the eye is governed by a definite
interest, and moves consecutively along the series of words, instead
of shifting irregularly about the page.

A moving object, or an object that is doing something, or even a
complex object that presents a number of parts to be examined in turn,
can hold the eye for some time. But it is almost impossible to hold
the eye fixed for any length of time on a simple, motionless,
unchanging object.

{252}

Attention is mobile because it is exploratory; it continually seeks
something fresh for examination. In the presence of a complex of
sights and sounds and touch stimuli, it tends to shift every second or
two from one part of the situation to another. Even if you are lying
in bed with your eyes closed, the movement of attention still appears
in the rapid succession of thoughts and images, and some shift usually
occurs as often as once a second.

A few simple experiments will serve to throw the shifting of attention
into clearer relief. Look fixedly at a single letter written on a
blank sheet of paper, and notice how one part after another of the
letter stands out; notice also that attention does not stick
absolutely to the letter, since thoughts obtrude themselves at
intervals.

  [Illustration:

    O O O
     O O
    O O O
     O O
    O O O

  Fig. 42.--A dot figure, from Sanford. Look steadily at it.]


Or, make a "dot figure", composed of six or eight or more dots
arranged either regularly or irregularly, and look steadily at the
collection. Probably you will find that the dots seem to fall into
figures and groups, and that the grouping changes frequently.
Objectively, of course, the dots are grouped in one way as much as
another, so that any particular grouping is your own doing. The
objective stimulus, in other words, is capable of arousing several
grouping reactions on your part, and does arouse different reactions
one after another

Shifting also appears in looking at an {253} "ambiguous figure", drawn
so as to represent equally well a solid object in either of two
different positions. The transparent cube, showing near and far edges
alike, is a good example. Look steadily at such a drawing, and the
cube will appear to shift its position from time to time. Numerous
such figures can be constructed; the most celebrated is the ambiguous
staircase. Look steadily at it, and suddenly you see the under side of
a flight of stairs, instead of the upper; and if you keep on looking
steadily, it shifts back and forth between these two positions.


[Illustration: Fig. 43.--The ambiguous cube figure.]


[Illustration: Fig. 44.--The ambiguous staircase figure.]


A still more striking case of shifting goes by the name of "binocular
rivalry", and occurs when colors or figures that we cannot combine
into a single picture are presented, {254} one to one eye, and the
other to the corresponding part of the other retina. Hold red glass
close in front of one eye and blue before the other, and look through
both at once towards a bright background, and you will see red part of
the time and blue part of the time, the two alternating as in the case
of ambiguous figures.


[Illustration: Fig. 45.--Another ambiguous figure, which can be seen
in three ways.]


The stereoscope is a great convenience in applying inconsistent
stimuli to the two eyes, and by aid of this instrument a great variety
of experiments can be made. It is thus found that, if the field before
one eye is a plain color, while the other, of a different color, has
any little figure on it, this figure has a great advantage over the
rival plain color and stays in sight most of the time. Anything moving
in one field has a similar advantage, and a bright field has the
advantage over a darker one. Thus the same factors of advantage hold
good in binocular rivalry as in native attention generally.

A different kind of shifting appears in what is called "fluctuation of
attention". Make a light gray smudge on a white sheet of paper, and
place this at such a distance that the gray will be barely
distinguishable from the white {255} background. Looking steadily at
the smudge, you will find it to disappear and reappear periodically.
Or, place your watch at such a distance that its ticking is barely
audible, and you will find the sound to go out and come back at
intervals. The fluctuation probably represents periodic fatigue and
recovery at the brain synapses concerned in observing the faint
stimulus.

Shiftings of the fluctuation type, or of the rivalry type either, are
not to be regarded as quite the same sort of thing as the ordinary
shiftings of attention. The more typical movement of attention is
illustrated by the eye movements in examining a scene, or by the
sequence of ideas and images in thinking or dreaming. Rivalry and
fluctuation differ from this typical shifting of attention in several
ways:

(1) The typical movement of attention is quicker than the oscillation
in rivalry or fluctuation. In rivalry, each appearance may last for
many seconds before giving way to the other, whereas the more typical
shift of attention occurs every second or so. In fact, during a
rivalry or fluctuation experiment, you may observe thoughts coming and
going at the same time, and at a more rapid rate than the changes in
the object looked at. Attention does not really hold steady during the
whole time that a single appearance of an ambiguous figure persists.

(2) Rivalry shifts are influenced very little, if at all, by the
factor of momentary desire or interest, and are very little subject to
control.

(3) In rivalry, the color that disappears goes out entirely, and in
looking at a dot figure or ambiguous figure you get the same effect,
since the grouping or appearance that gives way to another vanishes
itself for the time being. But when, in exploring a scene with the
eyes, you turn from one object to another, the object left behind
simply retires to the background, without disappearing altogether;
and, {256} in the same way, when attention shifts from one noise to
another, the first noise does not lapse altogether but remains vaguely
heard. Or when, in thinking of a number of people, one after another
comes to mind, the first one does not go out of mind altogether when
attention moves to the next, but remains still vaguely present for a
few moments.


Laws of Attention and Laws of Reaction in General

Shifting occurs also in reflex action. Let two stimuli be acting at
once, the one calling for one reflex and the other for the opposed
reflex (as flexion and extension of the same limb), and the result is
that only one of these reactions will occur at the same time, the
other being completely inhibited; but the inhibited reflex gets its
turn shortly, provided the two stimuli continue to act, and, in fact,
the two reactions may alternate in a way that reminds us of binocular
rivalry or ambiguous figures. Three fundamental laws of reaction here
come to light.

(1) The _law of selection_: of two or more inconsistent responses to
the same situation (or complex of stimuli), only one is made at the
same time.

(2) The _law of advantage_: one of the alternative responses has an
initial advantage over the others, due to such factors as intensity
and change in the stimulus, or to habits of reaction.

(3) The _law of shifting_: the response that has the initial advantage
loses its advantage shortly, and an alternative response is made,
provided the situation remains the same.

These three laws hold good of reactions at all levels, from reflex
action to rational thinking.

The mobility of attention obeys these same laws; only, attention is
livelier and freer in its movements than reflex action or than the
shifting in rivalry. Attention is more mobile and less bound to rigid
rules.


{257}

Sustained Attention

The mobility of attention is only half the story. When we speak, for
instance, of a student as having good powers of attention, we are not
thinking of mobility but rather of the opposite.

Eye movement, which we employed before as a picture of the movement of
attention, affords also a picture of sustained attention. Remember how
the eye moves in reading. Every second it shifts, but still it keeps
to the line of print. Just so, attention keeps moving forward in the
story we are reading, but sticks to the story. The more absorbed we
are in the story, the more rapidly we read. Attention is sustained
here, and still it moves. Sustained attention is not glued to one
point, by any means, but is simply confined to a given object or
theme, within which its motion may be as lively as ever.

What is it, then, that sustains attention? Evidently it is the factor
of present desire or interest, already mentioned. It is a
reaction-tendency, aroused to activity by some stimulus or other,
unable to reach its goal instantly, but persisting in activity for a
while and facilitating responses that are in its line, while
inhibiting others. Such a tendency facilitates response, i.e.,
attention, to certain stimuli, and inhibits attention to others, thus
causing them to be overlooked and neglected.

For the student, the ideal attention-sustainer is an interest in the
matter presented. If, however, he cannot get up any absorbing interest
in the subject-matter at once, he may generate the necessary motive
force by taking the lesson as a "stunt", as something to be mastered,
a spur to his self-assertion. In the old days, fear was often the
motive force relied upon in the schoolroom, and the switch hanging
{258} behind the efficient teacher's desk was the stimulus to
sustained attention. There must be _some_ tendency aroused if
attention is to be sustained. The mastery impulse is certainly
superior to fear for the purpose, but better than either is a genuine
interest in the subject studied.

In order to get up a genuine interest in a subject--an objective or
inherent interest--it is usually necessary to penetrate into the
subject for some little distance. The subject may not appeal to any of
our native impulses, or to any interest that has been previously
acquired, and how then are we to hold attention to it long enough to
discover its inherent interest? Curiosity will give us a start, but is
too easily satisfied to carry us far. Fear of punishment or
disapproval, hope of reward or praise, being put on our mettle, or
realizing the necessity of this subject for our future success, may
keep us going till we find the subject attractive in itself.

So, when the little child is learning to read, the printed characters
have so little attractiveness in themselves that he naturally turns
away from them after a brief exploration. But, because he is scolded
when his mind wanders from those marks, because other children make
fun of his blunders, because, when he reads correctly, he feels the
glow of success and of applause, he does hold himself to the printed
page till he is able to read a little, after which his interest in
what he is reading is sufficient, without extraneous motives, to keep
his nose between the covers of the story book more, perhaps, than is
good for him. The little child, here, is the type of the successful
student.

Attention to a subject thus passes through three stages in its
development. First comes the instinctive exploratory sort of
attention, favored by the native factors of advantage. Next comes the
stage of forced attention, driven by {259} extraneous motives, such as
fear or self-assertion. Finally arrives the stage of objective
interest. In the first and last stages attention is spontaneous, in
the middle stage forced. The middle stage is often called that of
voluntary attention, since effort has to be exerted to sustain
attention, while the first and last stages, being free from effort,
may be called involuntary.


Distraction

Distraction is an important topic for consideration in connection with
sustained attention. A distraction is a stimulus that attracts
attention away from the thing to which we mean to attend. There are
always competing stimuli, and the various factors of advantage,
especially desire or interest, determine which stimulus shall get
attention at any moment.

In the excited insane condition known as "mania" or the "manic state",
the patient is excessively distractible. He commences to tell you
something, all interest in what he has to say, but, if you pull out
your watch while he is talking, he drops his story in the middle of a
sentence and shifts to some remark about the watch. He seems to have
no impulse persistent enough to hold his thoughts steady. There are
contrary insane conditions in which it is almost impossible to
distract the patient from his own inner broodings, so much is he
absorbed in his own troubles.

Distraction is a favorite topic for experiment in the laboratory. The
subject is put to work adding or typewriting, and works for a time in
quiet, after which disturbances are introduced. A bell rings, a
phonograph record is played, perhaps a perfect bedlam of noise is let
loose; with the curious result that the subject, only momentarily
distracted, accomplishes more work rather than less. The distraction
has acted as a stimulus to greater effort, and by this effort {260} is
overcame. This does not always happen so in real life, but it shows
the possibilities of sustained attention.

There are several ways of overcoming a distraction. First, greater
energy may be thrown into the task one is trying to perform. The extra
effort is apt to show itself in gritting the teeth, reading or
speaking aloud, and similar muscular activity which, while entirely
unnecessary for executing the task in hand, helps by keeping the main
stream of energy directed into the task instead of toward the
distracting stimuli. Effort is necessary when the main task is
uninteresting, or when the distraction is specially attractive, or
even when the distraction is something new and strange and likely to
arouse curiosity. But one may grow accustomed or "adapted" to an
oft-recurring distraction, so as to sidetrack it without effort; in
other words, a habit of inattention to the distracting stimulus may be
formed. There is another, quite different way of overcoming a
distraction, which works very well where it can be employed, and that
is to couple the distraction to the main task, so as to deal with both
together. An example is seen in piano playing. The beginner at the
piano likes to play with the right band alone, because striking a note
with the left hand distracts him from striking the proper note with
the right. But, after practice, he couples the two hands, strikes the
bass note of a chord with the left hand while his right strikes the
other notes of the same chord, and much prefers two-handed to
one-handed playing. In short, to overcome a distraction, you either
sidetrack it or else couple it to your main task.


Doing Two Things at Once

The subject of distraction brings to mind the question that is often
asked, "Can any one do two things at once?" In this form, the question
admits of but one answer, for we {261} are always doing at least two
things at once, provided we are doing anything else besides breathing.
We have no trouble in breathing and walking at the same time, nor in
seeing while breathing and walking, nor even in thinking at the same
time. But breathing, walking, and seeing are so automatic as to
require no attention. The more important question then, is whether we
can do two things at once, when each demands careful attention.

The redoubtable Julius Caesar, of happy memory, is said to have been
able to dictate at once to several copyists. Now, Caesar's copyists
were not stenographers, but wrote in long-hand, so that he could speak
much faster than they could write. What he did, accordingly, was
undoubtedly to give the first copyist a start on the first letter he
wished to send, then turn to the second and give him a start on the
second letter, and so on, getting back to the first in time to keep
him busy. Quite an intellectual feat, certainly! But not a feat
requiring absolutely simultaneous attention to several different
matters. In a small way, any one can do something of the same kind. It
is not impossible to add columns of numbers while reciting a familiar
poem; you get the poem started and then let it run on automatically
for a few words while you add a few numbers, switch back to the poem
and then back to the adding, and so on. But in all this there is no
doing of two things, attentively, at the same instant of time.

You may be able, however, to combine two acts into a single
cooerdinated act, in the way just described under the head of
distraction, and give undivided attention to this compound act.


The Span of Attention

Similar to the question whether we can attentively perform more than a
single act at a time is the question of {262} how many different
objects we can attend to at once. The "span of attention" for objects
of any given kind is measured by discovering how many such objects can
be clearly seen, or heard, or felt, in a single instant of time.
Measurement of this "span" is one of the oldest experiments in
psychology. Place a number of marbles in a little box, take a single
peek into the box and see if you know how many marbles are there. Four
or five you can get in a single glance, but with more there you become
uncertain.

In the laboratory we have "exposure apparatus" for displaying a card
for a fifth of a second or less, just enough time for a single glance.
Make a number of dots or strokes on the card and see whether the
subject knows the number on sight. He can tell four or five, and
beyond that makes many mistakes.

Expose letters not making any word and he can read about four at a
glance. But if the letters make familiar words, he can read three or
four words at a glance. If the words make a familiar phrase, he gets a
phrase of several words, containing as many as twenty letters, at a
single glance.

Expose a number of little squares of different colors, and a
well-trained subject will report correctly as many as five colors,
though he cannot reach this number every time.


Summary of the Laws of Attention

Bringing together now what we have learned regarding the higher and
more difficult forms of attention, as revealed by sustained attention
and work under distraction, by the span of attention and by trying to
do two things at once, we find the previously stated three laws of
attention further illustrated, and a couple of new laws making their
appearance.

(1) The _law of selection_ still holds good in these more {263}
difficult performances, since only one attentive response is made at
the same instant of time. Automatic activities may be simultaneously
going on, but any two attentive responses seem to be inconsistent with
each other, so that the making of one excludes the other, in
accordance with the general law of selection.

What shall we say, however, of reading four disconnected letters at
the same time, or of seeing clearly four colors at the same time?
Here, it would seem, several things are separately attended to at
once. The several things are similar, and close together, and the
responses required are all simple and much alike. Such responses,
under such very favorable conditions, are perhaps, then, not
inconsistent with each other, so that two, three, or even four such
attentive responses may be made at the same time.

(2) The _law of advantage_ holds good, as illustrated by the fact that
some distractions are harder to resist than others.

(3) The _law of shifting_ holds good, as illustrated by the constant
movement of attention, even when it is "sustained", and by the
alternation between two activities when we are trying to carry them
both along simultaneously.

(4) The _law of sustained attention_, or of _tendency_ in attention,
is the same old law of tendency that has shown itself repeatedly in
earlier chapters. A tendency, when aroused to activity, facilitates
responses that are in its line and inhibits others. A tendency is thus
a strong factor of advantage, and it limits the shifting of attention.

(5) A new law has come to light, the _law of combination_, which reads
as follows: _a single response may be made to two or more stimuli_;
or, _two or more stimuli may arouse a single joint response_.

Even though, in accordance with the law of selection, only one
attentive response is made at the same time, more than {264} one
stimulus may be dealt with by this single attentive response. Groups
of four dots are grasped as units, familiar words are grasped as
units. Notice that these units are our own units, not external units.
Physically, a row of six dots is as much a unit as a row of four, but
we grasp the four as a unit in a way that we cannot apply to the six.
Physically, six letters are as much a unit when they do not form a
word as when they do; but we can make a unitary response to the six in
the one case and not in the other. The response is a unit, though
aroused by a number of separate stimuli.

The law of combination, from its name, is open to a possible
misconception, as if we reached out and grasped and combined the
stimuli, whereas ordinarily we do nothing to the stimuli, except to
see them and recognize them, or in some such way respond to them. The
combination is something that happens _in us_; it is our response. If
the expression were not so cumbersome, we might more accurately name
this law that of "unitary response to a plurality of stimuli".

Sometimes, indeed, we do make an actual motor response to two or more
stimuli, as when we strike a chord of several notes on the piano. The
law of combination still holds good here, since the movements of the
two hands are cooerdinated into a single act, which is thought of as a
unit ("striking a chord"), attended to as a unit, and executed as a
unit. Such cooerdinated movements may be called "higher motor units",
and we shall find much to say regarding them when we come to the
subject of learned reactions. The law of combination, all in all, will
be found later to have extreme importance in learned reactions.

Passing now to another side of the study of attention, we shall
immediately come across a sixth law to add to our list.

{265}

Attention and Degree of Consciousness

Up to this point, the introspective side of the psychology of
attention has not been considered. One of the surest of all
introspective observations belongs right here, to the effect that we
are more conscious of that to which we are attending than of anything
else. Of two stimuli acting at once upon us, we are the more conscious
of that one which catches our attention; of two acts that we perform
simultaneously, that one is more conscious that is performed
attentively.

We need not be entirely unconscious of the act or the stimulus to
which we are not attending. We may be dimly conscious of it. There are
degrees of consciousness. Suppose, for example, you are looking out of
the window while "lost in thought". You are most conscious of the
matter of your thoughts, but conscious to a degree of what you see out
of the window. Your eyes are focused on some particular object
outside, and you are more conscious of this than of other objects seen
in indirect vision, though even of these last you are not altogether
unconscious. Consciousness shades off from high light to dim
background.

The "field of attention" is the maximum or high light of
consciousness; it comprises the object under attentive observation,
the reaction attentively performed. The "field of consciousness"
includes the field of attention and much besides. It includes objects
of which we are vaguely aware, desires active but not clearly
formulated, feelings of pleasantness or unpleasantness, of tension,
excitement, confidence, etc.

Apparently the field of consciousness shades off gradually into the
field of unconscious activity. Some physiological processes go on
unconsciously, and very habitual movements may be almost or entirely
unconscious. The boundary {266} between what is vaguely conscious and
what is entirely unconscious is necessarily very vague itself, but the
probability is that the field of consciousness is broader than we
usually suspect, and that many activities that we ordinarily think of
as unconscious, because we do not observe them at the time nor
remember them later, lie really near the margin of the field of
consciousness, but inside that field. "Unconscious motives", such as
spite or pride often seem to be, are probably vaguely conscious rather
than unconscious. We shall return to the fascinating topic of the
unconscious at the close of the book.

Degree of consciousness does not always tally with intensity of
sensation or energy of muscular action. You may be more conscious of a
slight but significant sound than of much louder noises occurring at
the same time. You may be more conscious of a delicate finger movement
than of a strong contraction of big muscles occurring at the same
time. Degree of consciousness goes with degree of mental activity. Of
all the reactions we are making at the same time--and usually there
are several--the most active in a mental way is the most conscious.
The slight sound arouses intense mental response because it means
something of importance--like the faint cry of the baby upstairs,
noticed instead of the loud noises of the street. The delicate finger
movement aims at some difficult result, while the big muscles may be
doing their accustomed work automatically.

It is not always the most efficient mental process that is most
conscious; indeed, practising an act makes it both more efficient and
less conscious. It is, rather, the less efficient processes that
require attention, because they require mental work to keep them going
straight.

Our sixth law of attention, emerging from this introspective study, is
naturally of a different style from the remainder of the list, which
were objectively observed; yet it {267} is no less certain and perhaps
no less significant. It may be called:

(6) The _law of degrees of consciousness_, and thus stated: _An
attentive response is conscious to a higher degree than any
inattentive response made at the same time_. An inattentive response
may be dimly conscious or, perhaps, altogether unconscious. The less
familiar the response, and the higher it stands in the scale of mental
performances, the more attentive it is, and the more conscious.


The Management of Attention

Attentive observation is more trustworthy than inattentive, and also
gives more facts. Attentive movement is more accurate than
inattentive, and may be quicker as well. Attentive study gives quicker
learning than inattentive, and at the same time fixes the facts more
durably.

Shall we say, then, "Do everything attentively"? But that is
impossible. We sense so many stimuli at once that we could not
possibly attend to all of them. We do several things at once, and
cannot give attention to them all. A skilful performance consists of
many parts, and we cannot possibly give careful attention to all the
parts. Attention is necessarily selective, and the best advice is, not
simply to "be attentive", but to attend to the right things.

In observation, the best plan is obviously to decide beforehand
exactly what needs to be observed, and then to focus attention on this
precise point. That is the principle underlying the remarkably sure
and keen observation of the scientist. Reading may be called a kind of
observation, since the reader is looking for what the author has to
tell; and the rule that holds for other observation holds also for
reading. That is to say that the reader finds the most when he knows
just what he is looking for. We can learn {268} something here from
story-reading, which is the most efficient sort of reading, in the
sense that you get the point of the story better than that of more
serious reading matter, the reason being that attention is always
pressing forward in the story, looking for something very definite.
You want to know how the hero gets out of the fix he is in, and you
press forward and find out with great certainty and little loss of
time. The best readers of serious matter have a similar eagerness to
discover what the author has to say; they get the author's question,
and press on to find his answer. Such readers are both quick and
retentive. The dawdling reader, who simply spends so much time and
covers so many pages, in the vague hope that something will stick,
does not remember the point because he never got the point, and never
got it because he wasn't looking for it.

In skilled movement, or skilled action of any sort, the best rule is
to fix attention on the end-result or, if the process is long, on the
result that immediately needs to be accomplished. "Keep your eye on
the ball" when the end just now to be achieved is hitting the ball.
Attention to the details of the process, though necessary in learning
a skilled movement, is distracting and confusing after skill has been
acquired. The runner does not attend to his legs, but to the goal or,
if that is still distant, to the runner just ahead of him.


Theory of Attention

The chief facts to take account of in attempting to form a conception
of the brain action in attention are mobility, persistence in spite of
mobility, and focusing.

The mobility of attention must mean that brain activities are in
constant flux, with nerve currents continually shooting hither and
thither and arousing ever fresh groups of neurones; but sustained
attention means that a brain {269} activity (representing the desire
or interest or reaction-tendency dominant at the time) may persist and
limit the range of the mobile activities, by facilitating some of
these and inhibiting others.

The "focusing" of mental activity is more difficult to translate into
neural terms. The fact to be translated is that, while several mental
activities may go on at once, only one occupies the focus of
attention. This must mean that, while several brain activities go on
at once, one is superior in some way to the rest. The superiority
might lie in greater intensity of neurone action, or in greater
extent; that is, one brain activity is bigger in some way than any
other occurring at the same time--bigger either because the neurones
in it are working more energetically or because it includes a larger
number of active neurones.

But why should not two equally big brain activities sometimes occur at
the same moment, and attention thus be divided? The only promising
hypothesis that has been offered to explain the absence of divided
attention is that of "neurone drainage", according to which one or the
other of two neurone groups, simultaneously aroused to activity,
drains off the energy from the other, so putting a quietus on it.
Unfortunately, this hypothesis explains too much, for it would make it
impossible for minor brain activities to go on at the same time as the
major one, and that would mean that only one thing could be done at a
time, and that the field of consciousness was no broader than the
field of attention. On the whole, we must admit that we do not know
exactly what the focusing of attention can mean in brain terms.

{270}

EXERCISES

1. Outline the chapter, in the form of a number of "laws", putting
   under each law the chief facts that belong there.

2. See if you can verify, by watching another person's eyes, the
   statements made on page 250 regarding eye movements.

3. Choose a spot where there is a good deal going on, stay there
   for five minutes and jot down the things that attract your
   attention. Classify the stimuli under the several "factors of
   advantage".

4. Mention some stimulus to which you have a habit of attention,
   and one to which you have a habit of inattention.

5. Close the eyes, and direct attention to the field of cutaneous
   and kinesthetic sensations. Do sensations emerge of which you are
   ordinarily only dimly conscious? Does shifting occur?

6. Of the several factors of advantage, which would be most effective
   in catching another person's attention, and which in holding his
   attention?

7. How does attention, in a blind person, probably differ from that
   of a seeing person?

8. Doing two things at once. Prepare several columns of one-place
   numbers, ten digits in a column. Try to add these columns, at the
   same time reciting a familiar poem, and notice how you manage it,
   and how accurate your work is.

9. Consider what would be the best way to secure sustained
   attention to some sort of work from which your mind is apt to wander.



REFERENCES

Walter B. Pillsbury gives a full treatment of the subject in his book
on _Attention_, 1908, and a condensed account of the matter in Chapter
V of his _Essentials of Psychology_, 2nd edition, 1920.

Another full treatment is that of Titchener, in his _Textbook of
Psychology_, 1909, pp. 265-302.

On the topic of distraction, see John J. B. Morgan's _Overcoming of
Distraction and Other Resistances_, 1916.

{271}


CHAPTER XII

INTELLIGENCE

HOW INTELLIGENCE IS MEASURED, WHAT IT CONSISTS IN AND EVIDENCE OF ITS
BEING LARGELY A MATTER OF HEREDITY

Before leaving the general topic of native traits and passing to the
process of learning or acquiring traits, we need to complete our
picture of the native mental constitution by adding intelligence to
reflex action, instinct, emotion, feeling, sensation and attention.
Man is an intelligent animal by nature. The fact that he is the most
intelligent of animals is due to his native constitution, as the fact
that, among the lower animals, some species are more intelligent than
others is due to the native constitution of each species. A rat has
more intelligence than a frog, a dog than a rat, a monkey than a dog,
and a man than a monkey, because of their native constitutions as
members of their respective species.

But the different individuals belonging to the same species are not
all equal in intelligence, any more than in size or strength or
vitality. Some dogs are more intelligent than others, and the same is
notably true of men. Now, are these differences between members of the
same species due to heredity or environment? This question we can
better approach after considering the methods by which psychologists
undertake to measure intelligence; and an analysis of these methods
may also serve to indicate what is included under the term
"intelligence".

{272}

Intelligence Tests

Not far from the year 1900 the school authorities of the city of
Paris, desiring to know whether the backwardness of many children in
school resulted from inattention, mischievousness and similar
difficulties of a moral nature, or from genuine inability to learn,
put the problem into the hands of Alfred Binet, a leading psychologist
of the day; and within a few years thereafter he and a collaborator
brought out the now famous Binet-Simon tests for intelligence. In
devising these tests, Binet's plan was to leave school knowledge to
one side, and look for information and skill picked up by the child
from his elders and playmates in the ordinary experience of life.
Further, Binet wisely decided not to seek for any _single_ test for so
broad a matter as intelligence, but rather to employ many brief tests
and give the child plenty of chances to demonstrate what he had
learned and what he could do. These little tests were graded in
difficulty from the level of the three-year-old to that of the
twelve-year-old, and the general plan was to determine how far up the
scale the child could successfully pass the tests.

These were not the first tests in existence by any means, but they
were the first attempt at a measure of general intelligence, and they
proved extraordinarily useful. They have been added to and revised by
other psychologists, notably by Terman in America, who has extended
the scale of tests up to the adult level. A few samples from Terman's
revision will give an idea of the character of the Binet tests.

  From the tests for three-year-olds: Naming familiar objects--the
  child must name correctly at least three of five common objects that
  are shown him.

  Six-year test: Finding omissions in pictures of faces, from which
  the nose, or one eye, etc., is left out. Four such pictures are
  shown, and three correct responses are required to pass the test.

  Eight-year test: Tell how wood and coal are alike; and so with three
  other pairs of familiar things; two out of four correct responses
  are required to pass the test.

{273}

  Twelve-year test: Vocabulary test--rough definitions showing the
  child's understanding of forty words out of a standard list of one
  hundred.

The question may be raised, "Why such arbitrary standards-three out of
five required here, two out of four there, forty out of a hundred the
next time?" The answer is that the tests have been standardized by
actual trial on large numbers of children, and so standardized that
the average child of a given age can just barely pass the tests of
that age.

Intelligence is measured by Binet on a scale of _mental age_. The
average child of, let us say, eight years and six months is said to
have a mental age of eight years and six months; and any individual
who does just as well as this is said to have this mental age, no
matter what his chronological age may be. The average child of this
age passes all the tests for eight years and below, and three of the
six tests for age nine; or passes an equivalent number of tests from
the total series. Usually there is some "scatter" in the child's
successes, as he fails in a test here and there below his mental age,
and succeeds here and there above his mental age, but the failures
below and the successes above balance each other in the average child,
so that he comes out with a mental age equal to his chronological age.

  [Footnote: The Binet scale, it must be understood, is an instrument
  of precision, not to be handled except by one who has been
  thoroughly trained in its use. It looks so simple that any student
  is apt to say, "Why, I could give those tests!" The point is that he
  couldn't--not until he knew the tests practically by heart, not till
  he had standardized his manner of conducting them to agree perfectly
  with the prescribed manner and till he knew how to score the varying
  answers given by different children according to the scoring system
  that goes with the tests, and not till, by experience in handling
  children in the tests, he was able to secure the child's confidence
  and get him to do his best, without, however, giving the child any
  assistance beyond what is prescribed. Many superior persons have
  looked down on the psychological examiner with his (or her)
  assortment of little tests, and have said, "Certainly no special
  training is necessary to give these tests. You simply want to find
  out whether the child can do these stunts. I can find out as well as
  you." They miss the point altogether. The question is not whether
  the child can do these stunts (with an undefined amount of
  assistance), but whether he _does_ them under carefully prescribed
  conditions. The child is given two, three or four dozen chances to
  see how many of them he will accept; and the whole scale has been
  standardized by try-out on many children of each age, and so adapted
  that when given according to instructions, it will give a correct
  measure of the child's mental age. But when given by superior
  persons in ignorance of its true character, it gives results very
  wide of the mark. So much by way of caution.]

{274}

If a child's mental age is the same as his chronological age, he is
just average, neither bright nor dull. If his mental age is much above
his chronological, he is bright; if much below, dull. His degree of
brightness or dullness can be measured by the number of years his
mental age is above or below his chronological age. He is, mentally,
so many years advanced or retarded.

Brightness or dullness can also be measured by the _intelligence
quotient_, which is employed so frequently that it is customarily
abbreviated to "IQ". This is the mental age divided by the
chronological, and is usually expressed in per cent. The IQ of the
exactly average child, of any age, is 1, or 100 per cent. The IQ of
the bright child is above 100 and of the dull child below 100. About
sixty per cent. of all children have an IQ between 90 and 110, twenty
per cent, are below 90 and twenty per cent, above 110. The following
table gives the distribution in somewhat greater detail:

IQ below 70,  1%
IQ    70-79,  5%
IQ    80-89, 14%
IQ    90-99, 30%
IQ  100-109, 30%
IQ  110-119, 14%
IQ  120-129,  5%
IQ over 129,  1%
             ---
             100

{275}

For convenience, those with IQ under 70 are sometimes labeled
"feeble-minded", and the others, in order, "borderline", "low normal",
"average" (from 90 to 110), "superior", "very superior", "exceedingly
superior"; but this is arbitrary and really unscientific, for what the
facts show is not a separation into classes, but a continuous
gradation from one extreme to the other. The lower extreme is near
zero, and the upper extreme thus far found is about 180.

While the mental age tells an individual's intellectual level at a
given time, the IQ tells how fast he has progressed. An IQ of 125
means that he has picked up knowledge and skill 25 per cent. faster
than the average individual--that he has progressed as far in four
years as the average child does in five, or as far in eight as the
average does in ten, or as far in twelve as the average does in
fifteen. The IQ usually remains fairly constant as the child grows
older, and thus represents his rate of mental growth. It furnishes a
pretty good measure of the individual's intelligence.


Performance Tests

Since, however, the Binet tests depend greatly on the use of language,
they are not fair to the deaf child, nor to the child with a speech
defect, nor to the foreign child. Also, some persons who are clumsy in
managing the rather abstract ideas dealt with in the Binet tests show
up better in managing concrete objects. For all such cases,
_performance tests are useful. Language plays little part in a
performance test_, and concrete objects are used. The "form board" is
a good example. Blocks of various simple shapes are to be fitted into
corresponding holes in a board; the time of performance is measured,
and the errors (consisting in trying to put a block into a differently
shaped hole) are also counted. To the normal adult, this task seems
too simple {276} to serve as a test for intelligence, but the young
child finds it difficult, and the mentally deficient adult goes at it
in the same haphazard way as a young child, trying to force the square
block into the round hole. He does not pin himself down to the one
essential thing, which is to match blocks and holes according to
shape.

Another good performance test is the "picture completion". A picture
is placed before the child, out of which several square holes have
been cut. These cut-out pieces are mounted on little blocks, and there
are other similar blocks with more or less irrelevant objects pictured
on them. The child must select from the whole collection of little
blocks the one that belongs in each hole in the picture. The better
his understanding of the picture, the better his selection.


Group Testing

The tests so far described, because they have to be given to each
subject individually, require a great deal of time from the trained
examiner, and tests are also needed which can be given to a whole
group of people at once. For persons who can read printed directions,
a group test can easily be conducted, though much preliminary labor is
necessary in selecting and standardizing the questions used. Group
testing of foreigners, illiterates, and young children is more
difficult, but has been accomplished, the directions being conveyed
orally or by means of pantomime.

The first extensive use of group intelligence tests was made in the
American Army during the Great War. A committee of the American
Psychological Association prepared and standardized the tests, and
persuaded the Army authorities to let them try them out in the camps.
So successful were these tests--when supplemented, in doubtful cases,
by individual tests--that they were adopted in the receiving {277}
camps; and they proved very useful both in detecting those individuals
whose intelligence was too low to enable them to learn the duties of a
soldier, and those who, from high intelligence, could profitably be
trained for officers.

The "Alpha test", used on recruits who could read, consisted of eight
pages of questions, each page presenting a different type of problem
for solution. On the first page were rows of circles, squares, etc.,
to which certain things were to be done in accordance with spoken
commands. The subject had to attend carefully to what he was told to
do, since he was given each command only once, and some of the
commands called for rather complicated reactions. The second page
consisted of arithmetical problems, ranging from very simple at the
top of the page to more difficult ones below, though none of them went
into the more technical parts of arithmetic. One page tested the
subject's information on matters of common knowledge; and another
called for the selection of the best of three reasons offered for a
given fact, as, for example, "Why is copper used for electric wires?
Because--it is mined in Montana--it is a good conductor--it is the
cheapest metal." Another page presented disarranged sentences (as,
"wet rain always is", or "school horses all to go"), to be put
straight mentally, and indicated on the paper as true or false.

Many group tests are now in use, and among them some performance
tests. In the latter, pictures are often employed; sometimes the
subject has to complete the picture by drawing in a missing part,
sometimes he has to cancel from the picture a part that is
superfluous. He may have to draw a pencil line indicating the shortest
path through a maze, or he may have to continue a series of marks
which starts off according to a definite plan. The problems set him
under each class range from very easy to fairly difficult.

{278}

Some Results of the Intelligence Tests

The principal fact discovered by use of standardized intelligence
tests is that the tests serve very well the purpose for which they
were intended. In expert hands they actually give a fairly reliable
measure of the individual's intelligence. They have located the
trouble in the case of many a backward school child, whose
intelligence was too low to enable him to derive much benefit from the
regular school curriculum. His schooling needed to be adjusted to his
intelligence so as to prepare him to do what he was constitutionally
able to do.

On the other hand, it sometimes happens that a child who is
mischievous and inattentive in school, and whose school work is rather
poor, tests high in intelligence, the trouble with him being that the
work set him is below his mental level and therefore unstimulating.
Such children do better when given more advanced work. The
intelligence tests are proving of great service in detecting boys and
girls of superior intelligence who have been dragging along, forming
lazy habits of work, and not preparing for the kind of service that
their intelligence should enable them to give.

Some results obtained by the "Alpha test" are given in the following
table, and in the diagram which restates the facts of the table in
graphic form. The Alpha test included 212 questions in all, and a
correct answer to any question netted the subject one point. The
maximum score was thus 212 points, a mark which could only be obtained
by a combination of perfect accuracy and very rapid work (since only a
limited time was allowed for each page of the test). Very seldom does
even a very bright individual score over 200 points. The table shows
the approximate per cent, of individuals scoring between certain
limits; thus, {279} of men drafted into the Army, approximately 8 per
cent. scored below 15 points, 12 per cent. scored from 16 to 29
points, etc. Of college freshmen, practically none score below 76
points, 1 per cent. score from 76 to 89 points, etc.


             Per cent. of     Per cent. of
             drafted men      college freshmen
             making these     making these
             Scores           Scores
Scores
0-14 points     3              0

15-29          12              0

30-44          15              0

45-59          16              0

60-74          13              0

75-89          11              1

90-104          9              4

105-119         7              8

120-134         6             14

135-149         4             23

150-164         2             24

165-179         1.3           13

180-194         0.5            7

195-212         0.2            1
              -----          ---
              100            100


The "drafted men", consisting of men between the ages of twenty-one
and thirty-one, fairly represent the adult male white population of
the country, except in two respects. Many able young men were not
included in the draft, having previously volunteered for officers'
training camps or for special services. Had they been included, the
percentages making the higher scores would have gone up slightly. On
the other hand, many men of very low intelligence never reached the
receiving camps at all, being inmates of institutions for the
feebleminded or excluded from the draft because of known mental
deficiency; and, of those who reached {280} the camps, many, being
illiterate, did not take the Alpha test. It is for this reason that
the graph for drafted men stops rather short at the lower end; to
picture fairly the distribution of intelligence, it should taper off
to the left, beyond the zero of the Alpha test.


[Illustration: Fig. 46.--Distribution of the scores of drafted men,
and also of college freshmen, in the Alpha test. The height of the
broken line above the base line is made proportional to the percent of
the group that made the score indicated just below along the base
line. (Figure text: army median--65, freshman median--150)]


College freshmen evidently are, as they should be, a highly selected
group in regard to intelligence. The results obtained at different
colleges differ somewhat, and the figures here given represent an
approximate average of results obtained at several colleges of high
standing. The median {281} score for freshmen has varied, at different
colleges, from 140 to 160 points.

  [Footnote: The "median" is a statistical measure very similar to the
  average; but, while the average score would be obtained by adding
  together the scores of all the individuals and dividing the sum by
  the number of individuals tested, the median is obtained by
  arranging all the individual scores in order, from the lowest to the
  highest, and then counting off from either end till the middle
  individual is reached; his score is the median. (If the number of
  individuals tested is an even number, there are two middle
  individuals, and the point midway between them is taken as the
  median.) Just as many individuals are below the median as above it.
  The median is often preferred to the average in psychological work,
  not only because it is more easily computed, but because it is less
  affected by the eccentric or unusual performances of a few
  individuals, and therefore more fairly represents the whole
  population.]

It will be noticed in the graph that none of the freshmen score as low
as the median of the drafted men. All of the freshmen, in fact, lie
well above the median for the general population. A freshman who
scores below 100 points finds it very difficult to keep up in his
college work. Sometimes, it must be said, a freshman who scores not
much over 100 in the test does very well in his studies, and sometimes
one who scores very high in the test has to be dropped for poor
scholarship, but this last is probably due to distracting interests.

No such sampling of the adult female population has ever been made as
was afforded by the draft, and we are not in a position to compare the
average adult man and woman in regard to intelligence. Boys and girls
under twelve average almost the same, year by year, according to the
Binet tests. In various other tests, calling for quick, accurate work,
girls have on the average slightly surpassed boys of the same age, but
this may result from the fact that girls mature earlier than boys;
they reach adult height earlier, and perhaps also adult intelligence.
College women, in the Alpha test, score on the average a few points
below college men, but this, on the other hand, may be due to the fact
that the Alpha test, being prepared for men, includes a few questions
that lie rather outside the usual range of women's interests. On the
whole, tests have given very little evidence of any significant
difference between the general run of intelligence in the two sexes.


Limitations of the Intelligence Tests

Tests of the Binet or Alpha variety evidently do not cover the whole
range of intelligent behavior. They do not test {282} the ability to
manage carpenter's or plumber's tools or other concrete things, they
do not test the ability to manage people, and they do not reach high
enough to test the ability to solve really big problems.

Regarding the ability to manage concrete things, we have already
mentioned the performance tests, which provide a necessary supplement
to the tests that deal in ideas expressed in words. It is an
interesting fact that some men whose mental age is below ten,
according to the Binet tests, nevertheless have steady jobs, earn good
wages, and get on all right in a simple environment. There are many
others, with a mental age of ten or eleven, who cannot master the
school work of the upper grades, and yet become skilled workmen or
even real artists. Now, it takes mentality to perform skilled or
artistic work; only, the mentality is different from that demanded by
what we call "intellectual work".

Managing people requires tact and leadership, which are obviously
mental traits, though not easily tested. It is seldom that a real
leader of men scores anything but high in the intelligence tests, but
it more often happens that an individual who scores very high in the
tests has little power of leadership. In part this is a matter of
physique, or of temperament, rather than of intelligence, but in part
it is a matter of _understanding_ people and seeing how they can be
influenced and led.

Though the intelligence tests deal with "ideas", they do not, as so
far devised, reach up to the great ideas nor make much demand on the
superior powers of the great thinker. If we could assemble a group of
the world's great authors, scientists and inventors, and put them
through the Alpha test, it is probable that they would all score high,
but not higher than the upper ten per cent, of college freshmen. Had
their IQ's been determined when they were children, {283} probably all
would have measured over 180 and some as high as 200, but the tests
would not have distinguished these great geniuses from the gifted
child who is simply one of a hundred or one of a thousand.


The Correlation of Abilities

There is no opposition between "general intelligence", as measured by
the tests, and the abilities to deal with concrete things, with
people, or with big ideas. Rather, there is a considerable degree of
correspondence. The individual who scores high in the intelligence
tests is likely, but not certain, to surpass in these respects the
individual who scores low in the tests. In technical language, there
is a "positive correlation" between general intelligence and ability
to deal with concrete things, people and big ideas, but the
correlation is not perfect.

_Correlation_ is a statistical measure of the degree of
correspondence. Suppose, for an example, we wish to find out how
closely people's weights correspond to their heights. Stand fifty
young men up in single file in order of height, the tallest in front,
the shortest behind. Then weigh each man, and shift them into the
order of their weights. If no shifting whatever were needed, the
correlation between height and weight would be perfect. Suppose the
impossible, that the shortest man was the heaviest, the tallest the
lightest, and that the whole order needed to be exactly reversed; then
we should say that the correlation was perfectly inverse or negative.
Suppose the shift from height order to weight order mixed the men
indiscriminately, so that you could not tell _anything_ from a man's
position in the height order as to what his position would be in the
weight order; then we should have "zero correlation". The actual
result, however, would be that, while the height order would be {284}
somewhat disturbed in shifting to the weight order, it would not be
entirely lost, much less reversed. That is, the correlation between
height and weight is positive but not perfect.

Statistics furnishes a number of formulae for measuring correlations,
formulae which agree in this, that perfect positive correlation is
indicated by the number + 1, perfect negative correlation by the
number - 1, and zero correlation by 0. A correlation of +.8 indicates
close positive correspondence, though not perfect correspondence; a
correlation of +.3 means a rather low, but still positive,
correspondence; a correlation of -.6 means a moderate tendency towards
inverse relationship.

The correlation between two good intelligence tests, such as the Binet
and the Alpha, comes out at about +.8, which means that if a fair
sample of the general population, ranging from low to high
intelligence, is given both tests, the order of the individuals as
measured by the one test will agree pretty closely with the order
obtained with the other test. The correlation between a general
intelligence test and a test for mechanical ability is considerably
lower but still positive, coming to about +.4. Few if any real
negative correlations are found between different abilities, but low
positive or approximately zero correlations are frequent between
different, rather special abilities.

In other words, there is no evidence of any antagonism between
different sorts of ability, but there is plenty of evidence that
different special abilities may have little or nothing in common.

  [Footnote]
  Possibly some readers would like to see a sample of the
  statistical formulae by which correlation is measured. Here is one
  of the simplest. Number the individuals tested in their order as
  given by the first test, and again in their order as given by the
  second test, and find the difference between each individual's two
  rank numbers. If an individual who ranks no. 5 in one test ranks no.
  12 in the other, the difference in his rank numbers is 7. Designate
  this difference by the letter D. and the whole number of individuals
  tested by n. Square each D, and get the sum of all the squares,
  calling this sum "sum of D2[squared]". Then the correlation is given
  by the formula,

  1 - ( ( 6 X sum of D[squared] ) / (n x ( n[squared] - 1)) )

  As an example in the use of this formula, take the following:



  Individuals   Rank of each    Rank of each    D     D[squared]
  tested        individual in   individual in
                first test      second test

  Albert            3               5           2       4

  George            7               6           1       1

  Henry             5               3           2       4

  James             2               1           1       1

  Stephen           1               4           3       9

  Thomas            4               2           2       4

  William           6               7           1       1


  n = 7

  sum of D[squared] = 24

  n[squared] - 1 =    48

  6 x sum of D[squared] = 144

  6 x sum of D[squared] / n ( n[squared] - 1 )

  = 1 - 144/(7 x 48)

  = +.57

  In order to get a full and true measure of the correlation between
  two tests, the following precautions are necessary:

  (1) The _same individuals_ must be given both tests.

  (2) The number of individuals tested must be as great as 15 or 20,
  preferably more.

  (3) The individuals should be a fair sample of the population in
  regard to the abilities tested; they should not be so selected as to
  represent only a small part of the total range of ability.

  (4) The tests should be thorough enough to determine each
  individual's rank in each test, with a high degree of certainty.
  Sloppy testing gives a correlation nearer zero than it should be,
  because it "pies" the true orders to some extent.
  [End footnote]

{285}

General Factors in Intelligence

If now we try to analyze intelligence and see in what it consists, we
can best proceed by reviewing the intelligence tests, and asking how
it is that an individual succeeds in them. Passing the tests is a very
specific instance of {286} intelligent behavior, and an analysis of
the content of the tests should throw some light on the nature of
intelligence.

The first thing that strikes the eye in looking over the tests is that
they call for so many different reactions. They call on you to name
objects, to copy a square, to tell whether a given statement is true
or false, to tell wherein two objects are alike or different. The
first impression, then, is that intelligence consists simply in doing
a miscellaneous lot of things and doing them right.

But can we not state in more general terms how the individual who
scores high in the tests differs from one who scores low? If you
survey the test questions carefully, you begin to see that the person
who passes them must possess certain general characteristics, and that
lack of these characteristics will lead to a low score. We may speak
of these characteristics as "general factors" in intelligent behavior.

First, the tests evidently require the use of past experience. They
call, not for instinctive reactions, but for previously learned
reactions. Though the Binet tests attempt to steer clear of specific
school knowledge, they do depend upon knowledge and skill picked up by
the child in the course of his ordinary experience. They depend on the
ability to learn and remember. One general factor in intelligence is
therefore _retentiveness_.

But the tests do not usually call for simple memory of something
previously learned. Rather, what has been previously learned must be
applied, in the test, to a more or less novel problem. The subject is
asked to do something a little different from anything he has
previously done, but similar enough so that he can make use of what he
has learned. He has to _see the point_ of the problem now set him, and
to _adapt_ what he has learned to this novel situation. Perhaps
"seeing the point" and "adapting oneself to {287} a novel situation"
are to be held apart as two separate general factors in intelligence,
but on the whole it seems possible to include both under the general
head, _responsiveness to relationships_, and to set up this
characteristic as a second general factor in intelligence.

In the form board and picture completion tests, this responsiveness to
relationships comes out clearly. To succeed in the form board, the
subject must respond to the likeness of shape between the blocks and
their corresponding holes. In picture completion, he must see what
addition stands in the most significant relationship to the total
picture situation. In telling how certain things are alike or
different, he obviously responds to relationships; and so also in
distinguishing between good and poor reasons for a certain fact. This
element of response to relationships occurs again and again in the
tests, though perhaps not in the simplest, such as naming familiar
objects.

Besides these two intellectual factors in intelligent behavior, there
are certain moral or impulsive factors. One is _persistence_, which is
probably the same thing as the mastery or self-assertive instinct. The
individual who gives up easily, or succumbs easily to distraction or
timidity, is at a disadvantage in the tests or in any situation
calling for intelligent behavior.

But, as we said before, in discussing the instincts, excessive
stubbornness is a handicap in meeting a novel situation, which often
cannot be mastered by the first mode of response that one makes to it.
Some giving up, some _submissiveness_ in detail along with persistence
in the main effort, is needed. The too stubborn young child may waste
a lot of time trying with all his might to force the square block into
the round hole, and so make a poorer score in the test, than if he had
given up his first line of attack and tried something else.
Intelligent behavior must perforce {288} often have something of the
character of "trial and error", and trial and error requires both
persistence in the main enterprise and a giving up here in order to
try again there.

Finally, the instinct of _curiosity_ or exploration is evidently a
factor in intelligence. The individual who is stimulated by novel
things to explore and manipulate them will amass knowledge and skill
that can later be utilized in the tests, or in intelligent behavior
generally.


Special Aptitudes

We distinguish between the general factors in intelligence, just
mentioned, and special aptitudes for dealing with colors, forms,
numbers, weights etc. A special aptitude is a specific responsiveness
to a certain kind of stimulus or object. The special aptitudes are
factors in intelligent behavior--as we may judge from the content of
the intelligence tests--only, the tests are so contrived as not to
depend too much on any one or any few of the special aptitudes.
Arithmetical problems alone would not make a fair test for
intelligence, since they would lay undue stress on the special
aptitude for number; but it is fair enough to include them along with
color naming, weight judging, form copying, and word remembering, and
so to give many special aptitudes a chance to figure in the final
score.

There are tests in existence for some special aptitudes: tests for
color sense and color matching, for musical ability, for ability in
drawing, etc.; but as yet we have no satisfactory list of the special
aptitudes. They come to light when we compare one individual with
another, or one species with another. Thus, while man is far superior
to the dog in dealing with colors, the dog is superior in dealing with
odors. Man has more aptitude for form, but some animals are fully his
equal in sense of location and ability to find {289} their way. Man is
far superior in dealing with numbers and also with tools and
mechanical things. He is superior in speech, in sense of rhythm, in
sense of humor, in sense of pathos. Individual human beings also
differ markedly in each of these respects. They differ in these
special directions as well as in the "general factors" of
intelligence.


Heredity of Intelligence and of Special Aptitudes

Let us now return to the question raised at the very outset of the
chapter, whether or not intelligence is a native trait. We then said
that the differing intelligence of different species of animals must
be laid to their native constitutions, but left the question open
whether the differing intelligence of human individuals was a matter
of heredity or of environment.

Intelligence is of course quite different from instinct, in that it
does not consist in ready-made native reactions. The intelligence of
an individual at any age depends on what he has learned previously.
But the factors in intelligent behavior--retentiveness, responsiveness
to relationships, persistence, etc.--may very well be native traits.

But what _evidence_ is there that the individual's degree of
intelligence is a native characteristic, like his height or color of
hair? The evidence is pretty convincing to most psychologists.

First, we have the fact that an individual's degree of intelligence is
an inherent characteristic, in the sense that it remains with him from
childhood to old age. Bright child, bright adult; dull child, dull
adult. That is the rule, and the exceptions are not numerous enough to
shake it. Many a dull child of well-to-do parents, in spite of great
pains taken with his education, is unable to escape from his inherent
limitations. The intelligence quotient remains fairly {290} constant
for the same child as he grows up, and stands for an inherent
characteristic of the individual, namely, the rate at which he
acquires knowledge and skill. Give two children the same environment,
physical and social, and you will see one child progress faster than
the other. Thus, among children who grow up in the same community,
playing together and going to the same schools, the more rapid mental
advance of some than of others is due to differences in native
constitution, and the IQ gives a measure of the native constitution in
this respect. There are exceptions, to be sure, depending on physical
handicaps such as deafness or disease, or on very bad treatment at
home, but in general the IQ can be accepted as representing a fact of
native constitution.

Another line of evidence for the importance of native constitution in
determining degrees of intelligence comes from the study of mental
resemblance among members of the same family. Brothers or sisters test
more alike than children taken at random from a community, and twins
test more alike than ordinary brothers and sisters. Now, as the
physical resemblance of brothers or sisters, and specially of twins,
is accepted as due to native constitution, we must logically draw the
same conclusion from their mental resemblance.

The way feeble-mindedness runs in families is a case in point. Though,
in exceptional instances, mental defect arises from brain injury at
the time of birth, or from disease (such as cerebrospinal meningitis)
during early childhood, in general it cannot be traced to such
accidents, but is inherent in the individual. Usually mental defect or
some similar condition can be found elsewhere in the family of the
mentally defective child; it is in the family stock. When both parents
are of normal intelligence and come from families with no mental
abnormality in any ancestral line, it is practically unknown that they
should have a feeble-minded {291} child; but if mental deficiency has
occurred in some of the ancestral lines, an occasional feeble-minded
child may be born even of parents who are themselves both normal. If
one parent is normal and the other feeble-minded, some of the children
are likely to be normal and others feeble-minded; but if both parents
are feeble-minded, it is said that all the children are sure to be
feeble-minded or at least dull.

These facts regarding the occurrence of feeble-mindedness cannot be
accounted for by environmental influences, especially the fact that
some children of the same family may be definitely feeble-minded and
others normal. We must remember that children of the same parents need
not have precisely similar native constitutions; they are not always
alike in physical traits such as hair color or eye color that are
certainly determined by native constitution.

The special aptitudes also run in families. You find musical families
where most of the children take readily to music, and other families
where the children respond scarcely at all to music, though their
general intelligence is good enough. You find a special liking and
gift for mathematics cropping out here and there in different
generations of the same family. No less significant is the fact that
children of the same family show ineradicable differences from one
another in such abilities. In one family were two brothers, the older
of whom showed much musical ability and came early to be an organist
and composer of church music; while the younger, possessing
considerable ability in scholarship and literature, was never able to
learn to sing or tell one tune from another. Being a clergyman, he
desired very much to be able to lead in singing, but he simply could
not learn. Such obstinate differences, persisting in spite of the same
home environment, must depend on native constitution.

Native constitution determines mental ability in two respects. It
fixes certain limits which the individual cannot {292} pass, no matter
how good his environment, and no matter how hard he trains himself;
and, on the positive side, it makes the individual responsive to
certain stimuli, and so gives him a start towards the development of
intelligence and of special aptitudes.


Intelligence and the Brain

There is certainly some connection between the brain and intelligent
behavior. While the spinal cord and brain stem vary according to the
size of the body, and the cerebellum with the motility of the species
of animal, the size of the cerebrum varies more or less closely with
the intelligence of the species. It does vary also with bodily size,
as illustrated by the whale and elephant, which have the largest
cerebrum of all animals, including man. But the monkey, which shows
more intelligence than most animals, has also a very large cerebrum
for his size of body; and the chimpanzee and gorilla, considerably
surpassing the ordinary monkeys in intelligence, have also a much
larger cerebrum. The cerebrum of man, in proportion to the size of his
body, far surpasses that of the chimpanzee or gorilla.

The cerebrum varies considerably in size from one human individual to
another. In some adults it is twice as large as in others, and the
question arises whether greater intelligence goes with a larger brain.
Now, it appears that an extremely small cerebrum spells idiocy; not
all idiots have small brains, but all men with extremely small brains
are idiots. The brain weight of quite a number of highly gifted men
has been measured in post-mortem examination, and many of these gifted
men have had a very large cerebrum. On the whole, the gifted
individual seems to have a large brain, but there are exceptions, and
the relationship between brain size and intelligence cannot be very
close. Other factors must enter, one factor being undoubtedly the
fineness {293} of the internal structure of the cortex. Brain function
depends on dendrites and end-brushes, forming synapses in the cortex,
and such minute structures make little impression on the total brain
weight.

While intelligence is related to the cerebrum as a whole, rather than
to any particular "intelligence center", there is some likelihood that
the special aptitudes are related to special parts of the cortex,
though it must be admitted that few aptitudes have as yet been
localized. The pretended localizations of phrenology are all wrong.
But we do know that each sense has its special cortical area, and that
adjacent to these sensory areas are portions of the cortex intimately
concerned in response to different classes of complex stimuli. Near
the auditory center the cortex is concerned in recognizing spoken
words, and in following music; near the visual center it is concerned
in recognizing printed words, in recognizing seen objects, in finding
one's way by the sense of sight, etc. These special aptitudes thus
have a fairly definite cortical localization, and possibly others have
also.

Examined microscopically, the cortex shows differences of structure in
different parts, and to the structural differences probably correspond
differences of function. Now it is practically impossible that such a
function as attention or memory should have any localized cortical
center, for these are general functions. The instincts are specialized
enough to have local centers, but none have so far been localized.
What has been localized is of the nature of special aptitudes.

{294}

EXERCISES

1. Outline the chapter.

2. Pick out the true statements from the following list:

  (a) Man is the most intelligent of animals.

  (b) Intelligence depends on the development of the cerebellum.

  (c) It has not been found possible to use any single
      performance as a reliable index of intelligence.

  (d) Children of different mental ages may have the same IQ.

  (e) A child with a mental age of 10 years can do all the tests
      for 10 years and below, but none of those for the higher ages.

  (f) The intelligence tests depend wholly on accurate response
      and not at all on speed of reaction.

  (g) If intelligence tests depended upon previous training, they
      could not be measures of native intelligence.

  (h) High correlation between the test scores of brothers and
      sisters is a fact that tends to indicate the importance of
      heredity in determining intelligence.

  (i) The "general factors" in intelligence are the same as the
      instincts.

  (j) Feeble-minded individuals include all those who are below
      the average intelligence.

3. It is found that eminent men very often have eminent brothers,
   uncles and cousins. How would this fact be explained?

4. It is also found that the wives of eminent men often have eminent
   relatives. How would this fact be explained?

5. How could it happen that a boy of 9, in the third school grade,
   with an IQ of 140, should be mischievous and inattentive? What
   should be done with him?

6. If a boy of 12, by industrious work, does pretty well in the
   fourth grade, why should we not accept the teacher's estimate of
   him as a "fairly bright boy"?

7. How might the brain of an idiot be underdeveloped, aside from
   the matter of the number of nerve cells in the cortex?

8. Can it be that high intelligence is a disadvantage in any form
   of industrial work, and, if so, how?

9. Show how "general intelligence" and "special aptitudes" may
   work together to give success in some special line of work.

{295}

REFERENCES

For the Binet tests and some results obtained by their use, see Louis
M. Terman, _The Measurement of Intelligence_, 1916.

The group tests used in the American Army during the War are described
in detail In Vol. 15 of the _Memoirs of the National Academy of
Sciences_, 1921, edited by Robert M. Yerkes. This large book describes
the work of preparing and standardizing the tests, and also gives some
results bearing on the Intelligence of different sections of the
population. Some of the interesting results appear on pp. 507, 522,
528, 537, 693, 697, 705, 732, 743, 799, 815, 819, 829, 856 and 869.

For briefer treatments of the subject, see Walter S. Hunter's _General
Psychology_, 1919, pp. 36-58, and W. B. Pillsbury's _Essentials of
Psychology_, 2nd edition, 1920, pp. 388-407.

For the poor results obtained in attempting to judge intelligence from
photographs, see an illustrated article by Rudolph Pintner, in the
_Psychological Review_ for 1918, Vol. 25, pp. 286-296.

For a study of one of the special aptitudes, see C. E. Seashore's
_Psychology of Musical Talent_, 1919.

For a comprehensive survey of test methods and results, see the two
volumes of Whipple's _Manual of Mental and Physical Tests_, 2nd
edition, 1914, 1915.

{296}


CHAPTER XIII

LEARNING AND HABIT FORMATION

THE DEPENDENCE OF ACQUIRED REACTIONS UPON INSTINCT AND REFLEX ACTION,
AND THE MODIFICATION OF NATIVE REACTIONS BY EXPERIENCE AND TRAINING.


Already, in considering intelligence, we have partially rounded the
corner from native to acquired traits, and now, fairly around the
corner, we see ahead of us a long straight stretch of road. For there
is much to say regarding acquired traits and regarding the process of
acquisition. All knowledge is acquired, the whole stock of ideas, as
well as motor skill, and there are acquired motives in addition to the
native motive forces that we called instincts, and acquired likes and
dislikes in addition to those that are native; so that, all in all,
there are thousands on thousands of acquired reactions, and the daily
life of the adult is made up of these much more than of strictly
native reactions.

It will take us several chapters to explore this new territory that
now lies before us, a chapter on acquiring motor habits and skill, a
chapter on memory, a chapter on acquired mental reactions, and a
chapter devoted to the general laws that hold good in this whole
field. Our general plan is to proceed from the simple to the complex,
generalizing to some extent as we go, but leaving the big
generalizations to the close of the discussion, where we shall see
whether the whole process of acquiring reactions of all sorts cannot
be summed up in a few general laws of acquisition, or "laws of
association" as they are traditionally called. On reaching that {297}
goal, the reader may well come back, with the general laws in mind,
and see how well they fit in detail all the instances of acquired
responses that we are about to describe. We might have begun by
stating the general laws, but on the whole it will be better to
proceed "inductively", beginning with the observed facts and working
up to the general laws.


Acquired Reactions Are Modified Native Reactions

Though we have "turned a corner" in passing from native traits to
acquired, it would be a mistake to suppose we had left what is native
altogether behind. It would be a mistake to suppose that the
individual outgrew and left behind his native reactions and acquired
an entirely new outfit. The reactions that he acquires--or _learns_,
as we speak of acquisition in the sphere of reactions--develop out of
his native reactions. Consider this: how is the individual ever going
to learn a reaction? Only by reacting. Without native reactions, he
would be entirely inactive at the outset, and would never make a start
towards any acquisition. His acquired reactions, then, are his native
reactions modified by use.

The vast number of motor acts that the individual acquires are based
upon the reflexes. They are modified reflexes. The simplest kind of
modification is the mere _strengthening_ of an act by exercise. By his
reflex breathing and crying, the new-born baby exercises his lungs and
breathing muscles and the nerve centers that control them, with the
result that his breathing becomes more vigorous, his crying louder.
The strengthening of a reaction through exercise is a fundamental
fact.

But we should scarcely speak of "learning" if the only modification
consisted in the simple strengthening of native reactions, and at
first thought it is difficult to see how the {298} exercise of any
reaction could modify it in any other respect. But many reflexes are
not perfectly fixed and invariable, but allow of some free play, and
then exercise may fix or stabilize them, as is well illustrated in the
case of the pecking response of the newly hatched chick. If grains are
strewn before a chick one day old, it instinctively strikes at them,
seizes them in its bill and swallows them; but, its aim being poor and
uncertain, it actually gets, at first, only a fifth of the grains
pecked at; by exercise it improves so as to get over half on the next
day, over three-fourths after another day or two, and about 86 percent
(which seems to be its limit) after about ten days of practice.
Exercise has here modified a native reaction in the way of making it
more definite and precise, by strengthening the accurate movement as
against all the variations of the pecking movement that were made at
the start. Where a native response is variable, exercise tends towards
constancy, and so towards the _fixation_ of definite habits.

A reflex may come to be _attached_ to a new stimulus, that does not
naturally arouse it. A child who has accidentally been pricked with a
pin, and of course made the flexion reflex in response to this natural
stimulus, will make this same reaction to the sight of a pin
approaching his skin. The seen pin is a _substitute stimulus_ that
calls out the same response as the pin prick. This type of
modification gives a measure of control over the reflexes; for when we
pull the hand back voluntarily, or wink at will, or breathe deeply at
will, we are executing these movements without the natural stimulus
being present.

Voluntary control includes also the ability to omit a response even if
the natural stimulus is present. Holding the breath, keeping the eyes
wide open in spite of the tendency to wink, not swallowing though the
mouth is full of saliva, holding the hand steady when it is being
pricked, and many {299} similar instances of control over reflexes are
cases of _detachment_ of a native reaction from its natural stimulus.
Not "starting" at a sudden sound to which we have grown used and not
turning the eyes to look at a very familiar object, are other
instances of this detachment.

The _substitute response_ is another modification to be placed
alongside of the substitute stimulus. Here a natural stimulus calls
out a motor response different from its natural response. The muttered
imprecation of the adult takes the place of the child's scream of
pain. The loose holding of the pen between the thumb and the first two
fingers takes the place of the child's full-fisted grasp.

Finally, an important type of modification consists in the
_combination_ of reflex movements into larger cooerdinations. One hand
grasps an object, while the other hand pulls, pushes or strikes it.
Or, both hands grasp the object but in different ways, as in handling
an ax or shovel. These cases illustrate simultaneous cooerdination, and
there is also a serial cooerdination, in which a number of simple
instinctive movements become hitched together in a fixed order.
Examples of this are seen in dancing, writing a word, and, most
notably, in speaking a word or familiar phrase.

In these ways, by strengthening, fixing and combining movements, and
by new attachments and detachments between stimulus and response, the
instinctive motor activity of the baby passes over into the skilled
and habitual movement of the adult.


Acquired Tendencies

In the sphere of _impulse_ and _emotion_ the same kinds of
modification occur. Detachment of an impulse or emotion from its
natural stimulus is very much in evidence, since {300} what frightens
or angers or amuses the little child may have no such power with the
adult. One little boy of two could be thrown into gales of laughter by
letting a spoon drop with a bang to the floor; and you could repeat
this a dozen times in quick succession and get the response every
time. But this stimulus no longer worked when he had advanced to the
age of four.

The emotions get attached to substitute stimuli. Amusement can be
aroused in an older child by situations that were not at all amusing
to the baby. New objects arouse fear, anger, rivalry or curiosity. The
emotions of the adult--with the exception of sex attraction, which is
usually very weak in the child--are the emotions of the child, but
they are aroused by different stimuli.

Not only so, but the emotions express themselves differently in the
child and the adult. Angry behavior is one thing in the child, and
another thing in the adult, so far as concerns external motor action.
The child kicks and screams, where the adult strikes with his fist, or
vituperates, or plots revenge. The internal bodily changes in emotion
are little modified as the individual grows up--except that different
stimuli arouse them--but the overt behavior is greatly modified;
instead of the native reactions we find substitute reactions.

A little girl of three years, while out walking in the woods with her
family, was piqued by some correction from her mother, but, instead of
showing the instinctive signs of temper, she picked up a red autumn
leaf and offered it to her mother, with the words, very sweetly
spoken, "Isn't that a pretty leaf?" "Yes," said her mother,
acquiescently. "Wouldn't you like to have that leaf?" "Yes, indeed."
"I'll throw it away!" (in a savage tone of voice, and with a gesture
throwing the leaf away). Here we have an early form of substitute
reaction, and can glimpse how such {301} reactions become attached to
the emotions. The natural outlet for the child's anger was blocked,
probably because previous outbursts of rage had not had satisfactory
consequences, so that the anger was dammed up, or "bottled up", for
the instant, till the child found some act that would give it vent.
Now supposing that the substitute reaction gave satisfaction to the
child, we can well imagine that it would become attached to the angry
state and be used again in a similar case. Thus, without outgrowing
the emotions, we may outgrow emotional behavior that is socially
unacceptable.

Emotions are also combined, much as reflexes are combined. The same
object which on one occasion arouses in us one emotion may arouse
another emotion on another occasion, so that eventually, whenever we
see that object, we respond by a blend of the two emotions. Your chief
may terrify you on some occasions, at other times amaze you by his
masterly grasp on affairs, and again win your affection by his care
for your own welfare; so that your attitude toward "the boss" comes to
be a blend of fear, admiration and gratitude. Religion and patriotism
furnish good examples of compound emotions.

Well, then, adult behavior compared with the instinctive behavior of
the little child shows these several types of modification. This is
interesting, but it is not all we wish to know. We want to know how
the modification comes about; that is, we want to get an insight into
the process of learning. Scientifically, this is one of the most
fascinating topics in psychology--how we learn, how we are molded or
modified by experience--and practically, it is just as important,
since if we wish to educate, train, mold, improve ourselves or others,
it is the _process_ of modification that we must control; and to
control it we must understand it.

To understand it we must watch the process itself; and {302} therefore
we turn to studies that trace the course of events in human and animal
learning.


Animal Learning

Animals do learn, all the vertebrates, at least, and many of the
invertebrates. They often learn more slowly than men, but this is an
advantage for our present purpose, since it makes the learning process
easier to follow. Mere anecdotes of intelligent behavior in animals
are of little value, but experimental studies, in which the animal's
progress is followed, step by step, from the time when he is
confronted with a perfectly novel situation till he has mastered the
trick, have now been made in great numbers, and a few typical
experiments will serve as a good introduction to the whole subject of
learning.


The negative adaptation experiment.

Apply a harmless and meaningless stimulus time after time; at first
the animal makes some instinctive exploring or defensive reaction; but
with continued repetition of the stimulus, he ceases after a while to
respond. The instinctive reaction has been detached from one of its
natural stimuli.

Even in unicellular animals, negative adaptation can be observed, but
in them is only temporary, like the "sensory adaptation" described in
the chapter on sensation. Stop the stimulus and the original
responsiveness returns after a short time. Nothing has been learned,
for what is learned remains after an interval of rest.

In higher animals, permanent adaptation is common, as illustrated by a
famous experiment on a spider. While the spider was in its web, a
tuning fork was sounded, and the spider made the defensive reaction of
dropping to the ground. It climbed back to its web, the fork was
sounded again, the spider dropped again; but after several {303}
repetitions in quick succession, the spider ceased to respond. Next
day, to be sure, it responded as at first; but after the same
performance had been repeated on several days, it ceased permanently
to respond to this stimulus.

Negative adaptation is common in domestic animals, as well as in men.
The horse "gets used" to the harness, and the dog to the presence of a
cat in the house. Man grows accustomed to his surroundings, and to
numerous unimportant sights and sounds.


The conditioned reflex experiment.

Put into a dog's mouth a tasting substance that arouses the flow of
saliva, and at the same instant ring a bell; and repeat this
combination of stimuli many times. Then ring the bell alone, and the
saliva flows in response to the bell. The bell is a _substitute
stimulus_, which has become attached to the salivary response by dint
of having been often given along with the natural stimulus that
arouses this response. At first thought, this is very weird, but do we
not know of similar facts in every-day experience? The dinner bell
makes the mouth water; the sight of food does the same, even the name
of a savory dish will do the same.

Quite possibly, the learning process by which the substitute stimulus
becomes attached to the salivary reaction is more complex in man's
case. He may _observe_ that the dinner bell means dinner, whereas the
dog, we suppose, does not definitely observe the connection of the
bell and the tasting substance. What the experiment shows is that a
substitute stimulus can become attached to a reaction under very
simple conditions.

A conditioned reflex experiment on a child deserves mention. A young
child, confronted with a rabbit, showed no fear, but on the contrary
reached out his hand to take the rabbit. At this instant a loud
rasping noise was produced just behind the child, who quickly withdrew
his hand with {304} signs of fear. After this had been repeated a few
times, the child shrank from the rabbit and was evidently afraid of
it. Probably it is in this way that many fears, likes and dislikes of
children originate.


The signal experiment.

Place a white rat before two little doors, both just alike except that
one has on it a yellow circle. The rat begins to explore. If he enters
the door with the yellow sign, he finds himself in a passage which
leads to a box of food; if he enters the other door he gets into a
blind alley, which he explores, and then, coming out, continues his
explorations till he reaches the food box and is rewarded. After this
first trial is thus completed, place him back at the starting point,
and he is very apt to go straight to the door that previously led to
the food, for he learns simple locations very quickly. But meanwhile
the experimenter may have shifted the yellow sign to the other door,
connected the passage behind the marked door with the food box, and
closed off the other passage; for the yellow disc in this experiment
always marks the way to the food, and the other door always leads to a
blind alley. The sign is shifted irregularly from one door to the
other. Whenever the rat finds himself in a blind alley, he comes out
and enters the other door, so finally getting his reward on every
trial. But for a long time he seems incapable of responding to the
yellow signal. However, the experimenter is patient; he gives the rat
twenty trials a day, keeping count of the number of correct responses,
and finds the number to increase little by little, till after some
thirty days every response is correct and unhesitating. The rat has
learned the trick.

He learns the trick somewhat more rapidly if punishment for incorrect
responses is added to reward for correct responses. Place wires along
the floor of the two passages, and switch an electric current into the
blind alley, behind {305} the door that has no yellow circle on it.
When the rat enters the blind alley and gets a shock, he makes a
prompt avoiding reaction, scampering back to the starting point and
cowering there for some time; eventually he makes a fresh start,
avoids the door that led to the shock and therefore enters the other
door, though apparently without paying any attention to the yellow
sign, since when, on the next trial, the sign is moved, he avoids the
_place_ where he got the shock, without reference to the sign. But in
a series of trials he learns to follow the sign.

Learning to respond to a signal might be classified under the head of
substitute stimulus, since the rat learns to respond to a stimulus,
the yellow disk, that at first left him unmoved. But more careful
consideration shows this to be, rather, a case of substitute response.
The natural reaction of a rat to a door is to enter it, not to look at
its surface, but the experiment forces him to make the preliminary
response of attending to the appearance of the door before entering
it. The response of attending to the surface of the door is
substituted for the instinctive response of entering. Otherwise put:
the response of finding the marked door and entering that is
substituted for the response of entering any door at random.


The maze experiment.

An animal is placed in an enclosure from which it can reach food by
following a more or less complicated path. The rat is the favorite
subject for this experiment, but it is a very adaptable type of
experiment and can be tried on any animal. Fishes and even crabs have
mastered simple mazes, and in fact to learn the way to a goal is
probably possible for any species that has any power of learning
whatever. The rat, placed in a maze, explores. He sniffs about, goes
back and forth, enters every passage, and actually covers every square
inch of the maze at least once; and in the course of these
explorations {306} hits upon the food box. Replaced at the starting
point, he proceeds as before, though with more speed and less dallying
in the blind alleys. On successive trials he goes less and less deeply
into a blind alley, till finally he passes the entrance to it without
even turning his head. Thus eliminating the blind alleys one after
another, he comes at length to run by a fixed route from start to
finish.


[Illustration: Fig. 47.--(From Hicks.) Ground plan of a maze used in
experiments on the rat. The central square enclosure is the food box.
The dotted line shows the path taken by a rat on Its fourth trial,
which occupied 4 minutes and 2 seconds.]


At first thought, the elimination of useless moves seems to tell the
whole story of the rat's learning process; but careful study of his
behavior reveals another factor. When the rat approaches a turning
point in the maze, his course bends so as to prepare for the turn; he
does not simply advance to the turning point and then make the turn,
but several steps before he reaches that point are organized or
cooerdinated into a sort of unit.

{307}

  [Illustration: Fig. 48.--(From Watson.) Learning curve for the rat
  in the maze. This is a composite or average, derived from the
  records of four animals. The height of the heavy line above the base
  line, for any trial, indicates the number of minutes consumed in
  that trial in passing through the maze and reaching the food box.
  The gradual descent of the curve indicates the gradual decrease in
  time required, and thus pictures the progress of the animals in
  learning the maze.]


The combination of steps into larger units is shown also by certain
variations of the experiment. It is known that the rat makes little
use of the sense of sight in learning the maze, guiding himself mostly
by the muscle sense. Now if the maze, after being well learned, is
altered by shortening one of the straight passages, the rat runs full
tilt against the new end of the passage, showing clearly that he was
proceeding, not step by step, but by _runs_ of some length. Another
variation of the experiment is to place a rat that has learned a maze
down in the midst of it, instead of at {308} the usual starting point.
At first he is lost, and begins exploring, but, hitting on a section
of the right path, he gets his cue from the "feel" of it, and races
off at full speed to the food box. Now his cue could not have been any
single step or turn, for these would all be too much alike; his cue
must have been a familiar _sequence_ of movements, and that sequence
functions as a unit in calling out the rest of the habitual movement.


[Illustration: Fig. 49.--(From Watson.) A puzzle box. The animal must
here reach his paw out between the bars and raise the latch, _L_. A
spring then gently opens the door.]


In short, the rat learns the path by _elimination_ of false reactions
and by _combination_ of single steps and turns into larger
reaction-units.


The puzzle-box experiment.

Place a hungry young cat in a strange cage, with a bit of fish lying
just outside, and you are sure to get action. The cat extends his paw
between the slats but cannot reach the fish; he pushes his nose
between the slats but cannot get through; he bites the slats, claws at
anything small, shakes anything loose, and tries every part of the
cage. Coming to the button that fastens {309} the door, he attacks
that also, and sooner or later turns the button, gets out, and eats
the fish. The experimenter, having noted the time occupied in this
first trial, replaces the cat, still hungry, in the cage, and another
bit of fish outside. Same business, but perhaps somewhat quicker
escape. More trials, perhaps on a series of days, give gradually
decreasing times of escape. The useless reactions are gradually
eliminated, till finally the cat, on being placed in the cage, goes
instantly to the door, turns the button, goes out and starts to eat,
requiring but a second or two for the whole complex reaction. Perhaps
15 or 20 trials have been required to reach this stage of prompt,
unerring response. The course of improvement is rather irregular, with
ups and downs, but with no sudden shift from the varied reaction of
the first trial to the fixed reaction of the last. The learning
process has been gradual.

This is the typical instance of learning by "trial and error", which
can be defined as varied reaction with gradual elimination of the
unsuccessful responses and fixation of the successful one. It is also
a case of the substitute response. At first, the cat responds to the
situation by reaching or pushing straight towards the food, but it
learns to substitute for this most instinctive response the less
direct response of going to another part of the cage and turning a
button.

The cat in this experiment is evidently trying to get out of the cage
and reach the food. The situation of being confined in a cage while
hungry arouses an impulse or tendency to get out; but this tendency,
unable at once to reach its goal, is dammed up, and remains as an
inner directive force, facilitating reactions that are in the line of
escape and inhibiting other reactions. When the successful response is
hit upon, and the door opened, the dammed-up energy is discharged into
this response; and, by repetition, {310} the successful response
becomes closely attached to the escape-tendency, so as to occur
promptly whenever the tendency is aroused.

There is no evidence that the cat reasons his way out of the cage. His
behavior is impulsive, not deliberative. There is not even any
evidence that the cat clearly observes how he gets out. If he made a
clean-cut observation of the manner of escape, his time for escaping
should thereupon take a sudden drop, instead of falling off gradually
and irregularly from trial to trial, as it does fall off. Trial and
error learning is learning by doing, and not by reasoning or
observing. The cat learns to get out by getting out, not by seeing how
to get out.


Summary of Animal Learning

Let us take account of stock at this point, before passing to human
learning, and attempt to generalize what we have observed in animals
of the process of learning.

(1) _Elimination_ of a response, which means _detachment_ of a
response from the stimulus that originally aroused it, occurs in three
main cases:

  (a) Elimination occurs most quickly when the response brings actual
  _pain_; the animal makes the avoiding reaction to the pain and
  quickly comes to make this response to the place where the pain
  occurred; and thus the positive reaction to this place is
  eliminated.

  (b) Elimination occurs more gradually when the response, without
  resulting in actual pain, brings _failure_ or delay in reaching a
  goal towards which the animal is tending. The positive response of
  entering and exploring a blind alley grows weaker and weaker, till
  the blind alley is neglected altogether.

  (c) Elimination of a response also occurs, slowly, through _negative
  adaptation_ to a stimulus that is harmless and also useless.

{311}

(2) New _attachments_ or _linkages_ of stimulus and response occur in
two forms, which are called "substitute stimulus" and "substitute
response".

     [Footnote: The writer hopes that no confusion will be caused by
     his use of several words to express this same meaning.
     "Attachment of stimulus and response", "linkage of stimulus and
     response", "connection between stimulus and response", and "bond
     between stimulus and response", all mean exactly the same; but
     sometimes one and sometimes another seems to bring the meaning
     more vividly to mind.]

  (a) _Substitute stimulus_ refers to the case where the natural
  response is not itself modified, but becomes attached to another
  stimulus than the one that originally aroused it. This new linkage
  can sometimes be established by simply giving the original stimulus
  and the substitute stimulus at the same time, and doing so
  repeatedly, as in the conditioned reflex experiment.

  (b) _Substitute response_ refers to the case where the stimulus
  remaining as it originally was, a new reaction is attached to it in
  place of the original response. The conditions under which this
  takes place are more complex than those that give the substitute
  stimulus. A tendency towards some goal must first be aroused, and
  then blocked by the failure of the original response to lead to the
  goal. The dammed-up tendency then facilitates other responses, and
  gives trial and error behavior, till some one of the trial responses
  leads to the goal; and this successful response is gradually
  substituted for the original response, and becomes firmly attached
  to the situation and tendency.

(3) New _combinations of responses_ occur, giving higher motor units.


Human Learning

To compare human and animal learning, and notice in what ways the
human is superior, cannot but throw light on the whole problem of the
process of learning. It is obvious {312} that man learns more quickly
than the animals, that he acquires more numerous reactions, and a much
greater variety of reactions; but the important question is how he
does this, and how his learning process is superior.

We must first notice that all the forms of learning displayed by the
animal are present also in the human being. Negative adaptation is
important in human life, and the conditioned reflex is important, as
has already been suggested. Without negative adaptation, the adult
would be compelled to attend to everything that aroused the child's
curiosity, to shrink from everything that frightened the child, to
laugh at everything that amused the child. The conditioned reflex type
of learning accounts for a host of acquired likes and dislikes. Why
does the adult feel disgust at the mere sight of the garbage pail or
the mere name of cod liver oil? Because these inoffensive visual and
auditory stimuli have been associated, or paired, with odors and
tastes that naturally aroused disgust.

The signal experiment is duplicated thousands of times in the
education of every human being. He learns the meaning of signs and
slight indications; that is, he learns to recognize important facts by
aid of signs that are of themselves unimportant. We shall have much to
say on this matter in a later chapter on perception. Man learns signs
more readily than such an animal as the rat, in part because the human
being is naturally more responsive to visual and auditory stimuli. Yet
the human being often has trouble in learning to read the signs
aright. He assumes that a bright morning means good weather all day,
till, often disappointed, he learns to take account of less obvious
signs of the weather. Corrected for saying, "You and me did it", he
adopts the plan of always saying "you and I", but finds that this
quite unaccountably brings ridicule on him at times, so that gradually
he _may_ come to say the one or the {313} other according to obscure
signs furnished by the structure of the particular sentence. The
process of learning to respond to obscure signs seems to be about as
follows: something goes wrong, the individual is brought to a halt by
the bad results of his action, he then sees some element in the
situation that he had previously overlooked, responds to this element,
gets good results, and so--perhaps after a long series of
trials--comes finally to govern his action by what seemed at first
utterly insignificant.

Trial and error learning, though often spoken of as characteristically
"animal", is common enough in human beings. Man learns by impulsively
doing in some instances, by rational analysis in others. He would be
at a decided disadvantage if he could not learn by trial and error,
since often the thing he has to manage is very difficult of rational
analysis. Much motor skill, as in driving a nail, is acquired by
"doing the best you can", getting into trouble, varying your
procedure, and gradually "getting the hang of the thing", without ever
clearly seeing what are the conditions of success.


Human Compared With Animal Learning

Fairly direct comparisons have been made between human and animal
learning of mazes and puzzles. In the maze, the human subject has an
initial advantage from knowing he is in a maze and has to master it,
while the rat knows no more than that he is in a strange place, to be
explored with caution on the odd chance that it may contain something
eatable, or something dangerous. But, after once reaching the food
box, the rat begins to put on speed in his movements, and within a few
trials is racing through the maze faster than the adult man, though
not so fast as a child. Adults are more circumspect and dignified,
they make less speed, cover less distance, but also make fewer false
moves {314} and finish in less time. That is in the early trials;
adults do not hold their advantage long, since children and even rats
also reach complete mastery of a simple maze in ten or fifteen trials.

The chief point of superiority of adults to human children, and of
these to animals, can be seen in the adjacent table. It is in the
_first trial_ that the superiority of the adults shows most clearly.
They get a better start, and adapt themselves to the situation more
promptly. Their better start is due to (1) better understanding of the
situation at the outset, (2) more plan, (3) less tendency to "go off
on a tangent", i.e., to respond impulsively to every opening, without
considering or looking ahead. The adult has more inhibition, the child
more activity and responsiveness; the adult's inhibition stands him in
good stead at the outset, but the child's activity enables him to
catch up shortly in so simple a problem as this little maze.

  AVERAGE NUMBER OF ERRORS MADE, IN EACH TRIAL IN
  LEARNING A MAZE, BY RATS, CHILDREN AND ADULT MEN

  (From Hicks and Carr)


  Trial
  No.   Rats  Children  Adults

   1     53      35       10
   2     45       9       15
   3     30      18        5
   4     22      11        2
   5     11       9        6
   6      8      13        4
   7      9       6        2
   8      4       6        2
   9      9       5        1
  10      3       5        1
  11      4       1        0
  12      5       0        1
  13      4       1        1
  14      4       0        1
  15      4       1        1
  16      2       0        1
  17      1       0        1


  The table reads that, on the first trial in the maze, the rats
  averaged 53 errors, the children 35 errors, and the adults 10
  errors, and so on. An "error" consisted in entering a blind alley or
  in turning back on {315} the course. The subjects tested consisted
  of 23 rats, five children varying in age from 8 to 18 years, and
  four graduate students of psychology. The human maze was much larger
  than those used for the rats, but roughly about the same in
  complexity. Since rats are known to make little use of their eyes in
  learning a maze, the human subjects were blindfolded. The rats were
  rewarded by food, the others simply by the satisfaction of success.


The puzzle boxes used in experiments on animal learning are too simple
for human adults, but mechanical puzzles present problems of
sufficient difficulty. The experimenter hands the subject a totally
unfamiliar puzzle, and notes the time required by the subject to take
it apart; and this is repeated in a series of trials till mastery is
complete. In addition to taking the time, the experimenter observes
the subject's way of reacting, and the subject endeavors at the end of
each trial to record what he has himself observed of the course of
events.

The human subject's behavior in his first trial with a puzzle is often
quite of the trial and error sort. He manipulates impulsively; seeing
a possible opening he responds to it, and meeting a check he backs off
and tries something else. Often he tries the same line of attack time
and time again, always failing; and his final success, in the first
trial, is often accidental and mystifying to himself.

On the second trial, he may still be at a loss, and proceed as before;
but usually he has noticed one or two facts that help him. He is most
likely to have noticed _where_ he was in the puzzle when his
accidental success occurred; for it appears that _locations_ are about
the easiest facts to learn for men as well as animals. In the course
of a few trials, also, the human subject notices that some lines of
attack are useless, and therefore eliminates them. After a time he may
"see into" the puzzle more or less clearly, though sometimes he gets a
practical mastery of the handling of the puzzle, while still obliged
to confess that he does not understand it at all.

{316}

Insight, when it does occur, is of great value. Insight into the
general principle of the puzzle leads to a better general plan of
attack, and insight into the detailed difficulties of manipulation
leads to smoother and defter handling. The human "learning curve" (see
Figure 50) often shows a prolonged stretch of no improvement, followed
by an abrupt change to quicker work; and the subject's introspections
show that 76 per cent, or more of these sudden improvements followed
immediately after some fresh insight into the puzzle.


[Illustration: Fig. 50.--(From Ruger.) Curve for human learning of a
mechanical puzzle. Distance above the base line represents the time
occupied in each trial, the successive trials being arranged in order
from left to right. A drop in the curve denotes a decrease in time,
and thus an improvement. At _X_, the subject saw something about the
puzzle that he had not noticed before and studied it out with some
care, so increasing his time for this one trial, but bringing the time
down thereafter to a new and steady level.]


The value of insight appears in another way when the subject, after
mastering one puzzle, is handed another involving the same principle
in a changed form. If he has seen the principle of the first puzzle,
he is likely to carry over this knowledge to the second, and master
this readily; {317} but if he has simply acquired motor skill with the
first puzzle, without any insight into its principle, he may have as
hard a time with the second as if he had never seen the first.


Learning by Observation

"We learn by doing" is a true proverb, in the sense that we acquire a
reaction by making just that reaction. We must make a reaction in
order to get it really in hand, so that the proverb might be
strengthened to read, "To learn, we must do". But we should make it
false if we strengthened it still further and said "We learn _only_ by
doing". For human beings, at least, learn also by observing.

The "insight" just spoken of consists in observing some fact--often
some relationship--and the value of insight in hastening the process
of learning is a proof that we learn by observation as well as by
actual manipulation. To be sure, observation needs to be followed by
manipulation in order to give practical mastery of a thing, but
manipulation without observation means slow learning and often yields
nothing that can be carried over to a different situation.

Learning by observation is typically human. The adult's superiority in
tackling a maze may be summed up by saying that he observes more than
the child--much more than the animal--and governs his behavior by his
observations. The enormous human superiority in learning a simple
puzzle, of the sort used in experiments on animals, arises from seeing
at once the key to the situation.

A chimpanzee--one of the most intelligent of animals--was tested with
a simple puzzle box, to be opened from outside by turning a button
that prevented the door from opening. The device was so simple that
you would expect the animal to see into it at once. A banana was put
into the box and the door fastened with the button. The {318}
chimpanzee quickly found the door, and quickly found the button, which
he proceeded to pull about with one hand while pulling the door with
the other. Without much delay, he had the button turned and the door
open. After about three trials, he had a practical mastery of the
puzzle, showing thus considerable superiority over the cat, who would
more likely have required twelve or fifteen trials to learn the trick.
But now a second button was put on a few inches from the first, both
being just alike and operating in the same way. The chimpanzee paid no
attention to this second button, but turned the first one as before,
and when the door failed to open, kept on turning the first button,
opening it and closing it and always tugging at the door. After a
time, he did shift to the second button, but as he had left the first
one closed, his manipulation of the second was futile. It was a long,
hard job for him to learn to operate both buttons correctly; and the
experiment proved that he did not observe how the button kept the door
from opening, but only that the button was the thing to work with in
opening the door. At one time, indeed, in order to force him to deal
with the second button, the first one was removed, but he still went
to the place where it had been and fingered about there. What he had
observed was chiefly the place to work at in order to open the door.
We must grant that animals observe locations, but most of their
learning is by doing and not by observing.

Here is another experiment designed to test the ability of animals to
learn by observation. The experimenter takes two cats, one having
mastered a certain puzzle box, the other not, and places the untrained
cat where it can watch the trained one do its trick. The trained cat
performs repeatedly for the other's benefit, and is then taken away
and the untrained cat put into the puzzle box. But he has derived no
benefit from what has gone on before his eyes, and must learn by trial
{319} and error, the same as any other cat; he does not even learn any
more quickly than he otherwise would have done.

The same negative results are obtained even with monkeys, but the
chimpanzee shows some signs of learning by observation. One chimpanzee
having learned to extract a banana from a long tube by pushing it out
of the further end with a stick which the experimenter had kindly left
close by, another chimpanzee was placed where he could watch the first
one's performance and did watch it closely. Then the first animal was
taken away and the second given a chance. He promptly took the stick
and got the banana, without, however, imitating the action of the
first animal exactly, but pulling the banana towards him till he could
reach it. This has been called learning by imitation, but might better
be described as learning by observation.

Such behavior, quite rare among animals, is common in human children,
who are very observant of what older people do, and imitate them on
the first opportunity, though often this comes after an interval. The
first time a child speaks a new word is usually not right after he has
heard it. When, on previous occasions, he has heard this word, he has
not attempted to copy it, but now he brings it out of himself. He has
not acquired the word by direct imitation, evidently, but by what has
been called "delayed imitation", which consists in observation at the
time followed later by attempts to do what has been observed.
Observation does not altogether relieve the child of the necessity of
learning by trial and error, for often his first imitations are pretty
poor attempts; but observation gives him a good start and hastens the
learning process considerably. "Learning by imitation", then, is, more
properly, "learning by observation followed by trial and error" and
the reason so little of it appears in animals is their lack of
observation.

_Learning by thinking_ depends on observation, since in {320} thought
we make use of facts previously observed. Seldom, unless in the
chimpanzee and other manlike apes, do we see an animal that appears to
be thinking. The animal is always doing, or waiting, or sleeping. He
seems too impulsive to stop and think. But a man may observe something
in the present problem that calls previous observations to mind, and
by mentally combining observations made at different times may figure
out the solution before beginning motor manipulation. Usually,
however, some manipulation of the trial and error sort is needed
before the thought-out solution will work perfectly.

Sometimes mental rehearsal of a performance assists in learning it, as
we see in the beginner at automobile driving, who, while lying in bed
after his first day's experience, mentally goes through the motions of
starting the engine and then the car, and finds that this "absent
treatment" makes the car easier to manage the next day.

In summing up the points of superiority of human over animal learning,
we may note that--

1. Man is perhaps a quicker learner, anyway, without regard to his
better methods of learning. This, however, is open to doubt, in view
of the very rapid learning by animals of such reactions as the
avoidance of a place where they have been hurt.

2. Man is a better observer, and this is the great secret of his quick
learning. He is especially strong in observing relationships, or
"principles" as we often call them.

3. He has more control over his impulses, and so finds time and energy
for observing and thinking.

4. He is able to work mentally with things that are not present; he
remembers things he has seen, puts together facts observed at
different times, thinks over problems that are not actually
confronting him at the moment, and maps out plans of action.

{321}


The Learning of Complex Practical Performances

A great deal of light has been thrown on the learning process by
psychological studies of the course of improvement in mastering such
trades as telegraphy and typewriting.

A student of telegraphy was tested once a week to see how rapidly he
could send a message, and also how rapidly he could "receive a message
off the wire", by listening to the clicking of the sounder. The number
of letters sent or received per minute was taken as the measure of his
proficiency. This number increased rapidly in the first few weeks, and
then more and more slowly, giving a typical learning curve, or
"practice curve", as it is also called.


[Illustration: Fig. 51.--(From Bryan and Harter.) Practice curve of
student W. J. R. in learning telegraphy. The height of the curve
indicates the number of letters sent or received per minute. Therefore
a rise of the curve here indicates improvement.]


The curve for sending, aside from minor irregularities, rose with a
fairly smooth sweep, tapering off finally towards the "physiological
limit", the limit of what the nerves and muscles of this individual
could perform.

  [Footnote: A good example of the physiological limit is seen in the
  hundred yard dash, since apparently no one, with the best of
  training, can lower the record much below ten seconds; and any given
  individual's limit may be considerably worse than this, according to
  his build, muscular strength and quickness of nerve centers. The
  simple reaction gives another good example; every one has his limit,
  beyond which no amount of training will lower his reaction time; the
  neuromuscular system simply will not work any faster.]


The receiving {322} curve rose more slowly than the sending curve, and
flattened out after about four months of practice, showing little
further improvement for the next two months. This was a discouraging
time for the student, for it seemed as if he could never come up to
the commercial standard. In fact, many learners drop out at this
stage. But this student persisted, and, after the long period of
little improvement, was gratified to find his curve going up rapidly
again. It went up rapidly for several months, and when it once more
tapered off into a level, he was well above the minimum standard for
regular employment.

Such a flat stretch in a practice curve, followed by a second
rise--such a period of little or no improvement, followed by rapid
improvement--is called a "plateau". Sometimes due to mere
discouragement, or to the inattention that naturally supervenes when
an act becomes easy to perform, it often has a different cause. It
may, in fact, represent a true physiological limit for the act as it
is being performed, and the subsequent rise to a higher level may
result from _improved methods_ of work. That was probably the case
with the telegrapher.

  [Footnote: A plateau of this sort is present in the learning curve
  for mastery of a puzzle, given on p. 316.]

The telegrapher acquires skill by improving his methods, rather than
by simply speeding up. He acquires methods that he didn't dream of at
first. At the start, he must learn the alphabet of dots and dashes.
This means, for purposes of sending, that he must learn the little
rhythmical pattern of finger movements that stands for each letter;
and, for purposes of receiving, that he must learn the rhythmical
{323} pattern of clicks from the sounder that stands for a letter.
When he has learned the alphabet, he is able to send and receive
slowly. In sending, he spells out the words, writing each letter as a
separate act. In receiving, at this early stage, he must pick out each
separate letter from the continuous series of clicks that he hears
from the sounder. By degrees, the letters become so familiar that he
goes through this spelling process easily; and, doing now so much
better than at the outset, he supposes he has learned the trade, in
its elements, and needs only to put on more speed.

But not at all! He has acquired but a small part of the necessary
stock-in-trade of the telegrapher. He has his "letter habits", but
knows nothing as yet of "word habits". These gradually come to him as
he continues his practice. He comes to know words as units, motor
units for sending purposes, auditory units for receiving. The
rhythmical pattern of the whole word becomes a familiar unit. Short,
much used words are first dealt with as units, then more and more
words, till he has a large vocabulary of word habits. A word that has
become a habit need not be spelled out in sending, nor laboriously dug
out letter by letter in receiving; you simply think the word "train",
and your finger taps it out as a connected unit; or, in receiving, you
recognize the characteristic pattern of this whole series of clicks.
When the telegrapher has reached this word habit stage, he finds the
new method far superior, in both speed and sureness, to the letter
habit method which he formerly assumed to be the whole art of
telegraphy. He does not even stop with word habits, but acquires a
similar control over familiar phrases.


Higher Units and Overlapping

The acquisition of skill in telegraphy consists mostly in learning
these _higher units_ of reactions. It is the same in {324} learning to
typewrite. First you must learn your alphabet of letter-striking
movements; by degrees you reduce these finger movements to firm
habits, and are then in the letter-habit stage, in which you spell out
each word as you write it. After a time, you write a familiar word
without spelling it, by a cooerdinated series of finger movements; you
write by word units, and later, in part, by phrase units; and these
higher units give you speed and accuracy.

Along with this increase in the size of the reaction-units employed
goes another factor of skill that is really very remarkable. This is
the "overlapping" of different reactions, a species of doing two or
more things at once, only that the two or more reactions are really
parts of the same total activity. The simplest sort of overlap can be
illustrated at an early stage in learning to typewrite. The absolute
beginner at the typewriter, in writing "and", pauses after each letter
to get his bearings before starting on the next; but after a small
amount of practice he will locate the second letter on the keyboard
while his finger is still in the act of striking the first letter.
Thus the sensory part of the reaction to the second letter commences
before the motor part of reacting to the first letter is finished; and
this overlap does away with pauses between letters and makes the
writing smoother and more rapid.

With further practice in typewriting, when word habits and phrase
habits are acquired, overlap goes to much greater lengths. One expert
kept her eyes on the copy about four words ahead of her fingers on the
keyboard, and thus was reacting to about four words at the same time:
one word was just being read from the copy, one word was being
written, and the two words between were being organized and prepared
for actual writing. The human typewriting mechanism, consisting of
eye, optic nerve, parts of the brain and cord, motor nerves and
muscles, works somewhat like one of {325} those elaborate machines
which receive raw material steadily at one end perform a series of
operations upon it, and keep turning out finished product at the other
end.

All this is very remarkable, but the same sort of overlapping and
working with large units can be duplicated in many linguistic
performances that every one makes. In reading aloud, the eyes keep
well ahead of the voice, and seeing, understanding and pronouncing are
all applied simultaneously to different words of the passage read. In
talking, the ideas keep developing and the spoken words tag along
behind.


[Illustration: Fig. 52.--(From Book.) Practice curve of a young man
learning to typewrite. Each point on the "curve" represents a daily
record in number of strokes per minute. With improvement, the curve
rises.]


In telegraphy and typewriting, it is almost inevitable that the
learner should start with the alphabet and proceed to gradually larger
units. But in learning to talk, or to read, the process goes the other
way. The child understands spoken words and phrases before breaking
them up into their elementary vocal sounds; and he can better be
taught to read by beginning with whole words, or even with whole {326}
sentences, than by first learning the alphabet and laboriously
spelling out the words. In short, the learning process often takes its
start with the higher units, and reaches the smaller elements only for
the purpose of more precise control.


Moderate Skill Acquired in the Ordinary Day's Work

Merely repeating a performance many times does not give the high
degree of skill that we see in the expert telegrapher or typist.
Ordinarily, we practise much less assiduously, are much less zealous,
and have no such perfect measure of the success of our work. For
"practice to make perfect", it must be strongly motivated, and it must
be sharply checked up by some index or measure of success or failure.
If the success of a performance can be measured, and chalked up before
the learner's eyes in the form of a practice curve, so that he can see
his progress, this acts as a strong incentive to rapid improvement.

Ordinarily, we have no clear indication of exactly how well we are
doing, and are satisfied if we get through our job easily and without
too much criticism and ridicule from people around. Consequently we
reach only a moderate degree of skill, nowhere near the physiological
limit, and do not acquire the methods of the real expert.

This is very true of the manual worker. Typesetters of ten or more
years' experience were once selected as subjects for an experiment on
the effects of alcohol, because it was assumed that they must have
already reached their maximum skill. In regard to alcohol, the result
was that this drug caused a falling off in speed and accuracy of
work--but that is another story. What we are interested in here is the
fact that, as soon as these long-practised operators found themselves
under observation, and their work measured, they all began to improve
and in the course of a couple of weeks {327} reached quite a new level
of performance. Their former level had been reasonably satisfactory
under workaday conditions, and special incentive was needed to make
them approach their limit.

A similar condition of affairs has been disclosed by "motion studies"
in many kinds of manual work; the movements of the operative have been
photographed or closely examined by the efficiency expert, and
analyzed to determine whether there are any superfluous movements that
could be eliminated, and whether a different method of work would be
economical of time and effort. Usually, superfluous motion has been
found and considerable economy seen to be possible. There is evidently
no law of learning to the effect that continued repetition of a
performance necessarily makes it perfect in speed, ease, or adaptation
to the task in hand. What the manual worker attains as the result of
prolonged experience is a passable performance, but not at all the
maximum of skill.

The brain worker has little to brag of as against the manual worker.
He, too, is only moderately efficient in doing his particular job.
There are brilliant exceptions--bookkeepers who add columns of figures
with great speed and precision, students who know just how to put in
two hours of study on a lesson with the maximum of effect, writers who
always say just what they wish to say and hit the nail on the head
every time--but the great majority of us are only passable. We need
strong incentive, we need a clear and visible measure of success or
failure, we need, if such a thing were possible, a practice curve
before us to indicate where we stand at the present moment with
respect to our past and our possible future.

{328}

Habit

A habit is contrasted with a reflex, in that the reflex is native, the
habit acquired; but both are alike in being prompt and automatic
reactions. The best antithesis to a habit is the response of a person
to a novel situation, where neither nature nor previous experience
gives him a ready response. The new response is exploratory and
tentative, while habit is fixed and definite. The new response is
variable, the habit regular. The new response is slow and uncertain,
the habit fairly quick and accurate. The new response is attended by
effort and strained attention, the habit is easy and often only
half-conscious. The new response is apt to be unsatisfying to the one
who makes it, while habit is comfortable and a source of satisfaction.

To break a habit is most uncomfortable. Nature--at least that "second
nature" which is habit--calls aloud for the customary performance.
Strenuous effort is required to get out of the rut, and the slipping
back into the rut which is almost sure to occur in moments of
inadvertence is humiliating. Result--usually the habit sticks.

But if the habit simply must be broken? Breaking a habit is forming a
counter-habit, and the more positive the counter-habit the better for
us. This counter-habit must not be left to form itself, but must be
practised diligently. Strong motivation is necessary, no half-hearted
acquiescence in somebody else's injunction to get rid of the habit. We
must adopt the counter-habit as ours, and work for a high standard of
skill in it. For example, if we come to realize that we have a bad
habit of grouchiness with our best friends, it is of little use merely
to attempt to deaden this habit; we need to aim at being a positive
addition to the company whenever we are present, and to practise the
art of being good company, checking up our efforts to be sure we are
hitting {329} the right vein, and persisting in our self-training till
we become real artists. It takes some determination for a grouchy
individual to make such a revolution in his conduct; his
self-assertion resists violently, for the grouchiness is part and
parcel of himself and he hates to be anything but himself. He must
conceive a new and inspiring ideal of himself, and start climbing up
the practice curve towards the new ideal.

{330}

EXERCISES

1. Outline the chapter.

2. Which of the acts performed in eating breakfast are instinctive,
   which are matters of habit, and which are partly the one and partly
   the other?

3. Compare your mental attitude in approaching an unfamiliar and
   a familiar task.

4. How does the performance of the expert in swimming or dancing, etc.,
   differ from the performance of the beginner? Analyze out the points
   of superiority.

5. Show that the element of trial and error is present in (a) the
   child's learning to pronounce a word, and (b) learning "how to
   take" a person so as to get on well with him.

6. Why is it that our handwriting, though exercised so much, is apt
   to grow worse rather than better, while on the contrary our
   spelling is apt to improve?

7. How would you rate your efficiency in study? Is it near your
   physiological limit, on a plateau, or in a stage of rapid
   improvement?

8. A practice experiment. Take several pages of uniform printed
   matter, and mark it off into sections of 15 lines. Take your time
   for marking every word in one section that contains both e and r.
   The two letters need not be adjacent, but must both be present
   somewhere In the word. Having recorded your time for this first
   section, do the same thing with the next section, and so on for 12
   sections. What were you able to observe, introspectively, of your
   method of work and changes with practice. From the objective
   observations, construct a practice curve.

9. Write brief explanations of the following terms:
     practice
     habit
     higher unit
     overlapping
     plateau
     physiological limit
     insight
     trial and error
     negative adaptation
     substitute stimulus
     substitute response
     conditioned reflex

{331}

REFERENCES

Thorndike's _Animal Intelligence, Experimental Studies,_ 1911, reports
his own pioneer work in this field. See also Chapter X in the same
author's _Educational Psychology, Briefer Course_, 1914.

For other reviews of the work on animal learning, see Watson's
_Behavior_, 1914, pp. 184-250; also Washburn's _Animal Mind_, 2nd
edition, 1917, pp. 257-312.

For human learning and practice, see Thorndike's _Educational
Psychology, Briefer Course_, 1914, Chapters XIV and XV; also Starch's
_Educational Psychology_, 1919, Chapter XI.

For an experiment showing the acquisition of fears by a child, see
Watson and Raynor, "Conditioned Emotional Reactions", in the _Journal
of Experimental Psychology_, 1920, Vol. 3, pp. 1-14.

James's chapter on "Habit", in his _Principles of Psychology_, 1890,
Vol. I, is a classic which every one should read.


{332}

CHAPTER XIV

MEMORY

HOW WE MEMORIZE AND REMEMBER, AND IN WHAT
RESPECTS MEMORY CAN BE MANAGED AND IMPROVED

So much depends on a good memory in all walks of life, and especially
in brain work of any sort, that perhaps it is no wonder that many
students and business and professional men become worried about their
memories and resort to "memory training courses" in the hope of
improvement. The scientific approach to this very practical problem
evidently lies through a careful study of the way in which memory
works, and the general problem may be expressed in the question, how
we learn and remember. This large problem breaks up, on analysis, into
four subordinate questions: how we commit to memory, how we retain
what has been committed to memory, how we get it back when we want it,
and how we know that what we now get back is really what we formerly
committed to memory. In the case of a person's name which we wish to
remember, how do we "fix it in mind", how do we carry it around with
us when we are not thinking of it, how do we call it up when needed,
and what assures us that we have called up the right name? The four
problems may be named those of

  (1) Memorizing, or learning,
  (2) Retention
  (3) Recall
  (4) Recognition

{333}

The Process of Memorizing

As memorizing is one sort of learning, what we have found in the
preceding chapter regarding the learning process should throw light on
our present problem. We found animals to learn by doing, and man by
doing and also by observation or observation combined with doing.
Observation is itself a form of doing, a mental reaction as
distinguished from a purely passive or receptive state; so that
learning is always active. Observation we found to be of great
assistance, both by way of hastening the learning process, and by way
of making what is learned more available for future use. Our previous
studies of learning thus lead us to inquire whether committing to
memory may not consist partly in rehearsing what we wish to learn, and
partly in observing it. Learning by rote, or by merely repeating a
performance over and over again, is, indeed, a fact; and observant
study is also a fact.

Let us see how learning is actually done, as indicated by laboratory
experiments. The psychologist experiments a great deal with the
_memorizing of nonsense material_, because the process can be better
observed here, from the beginning, than when sensible material is
learned. Suppose a list of twenty one-place numbers is to be studied
till it can be recited straight through. The learner may go at it
simply by "doing", which means here by reading the list again and
again, in the hope that it will finally stick. This pure rote learning
will perhaps do the job, but it is slow and inefficient. Usually the
learner goes to work in quite a different way. He observes various
facts about the list. He notices what numbers occur at the beginning
and end, and perhaps in other definite positions. He may group the
digits into two-place or three-place numbers, and notice the
characteristics of these. Any familiar combinations that {334} may
occur, such as 1492, he is likely to spy and remember. Lacking these,
he can at least find similar and contrasting number-groups.

For example, the list

  5 7 4 0 6 2 7 3 5 1 4 0 9 2 8 6 3 8 0 1,

which at first sight seemed rather bare of anything characteristic,
was analyzed in a way partly indicated by the commas and semicolons,

  5, 74, 0; 62, 73; 5140; 9, 286; 380, 1,

and memorized easily. These observed facts transformed the list from a
shapeless mass into something having definite characteristics, and the
observed characteristics stuck in mind and held the rest together.

Lists of nonsense syllables, such as

  wok  pam  zut  bip  seg  ron  taz  vis  lab  mer  koj  yad

are apt to be learned largely by observation of similarities and
contrasts, by reading meanings into the syllables, and by grouping
into pairs and reading rhythmically. Grouping reduces the twelve
syllables to six two-syllabled nonsense words, some of which may
suggest meaningful words or at least have a swing that makes them easy
to remember. Perhaps the first syllable of every pair is accented, and
a pause introduced after each pair; such devices assist memorizing.

The rhythmical and other _groups_ that are found or made by the
learner in memorizing nonsense lists are, in effect, "higher units",
and have much the same value as the higher units of telegraphy or
typewriting. One who learns many lists in the course of a laboratory
experiment develops a {335} regular system of grouping. First he reads
the list through, in groups of two, three or four items, noticing each
group as a whole; later, he notices the items in each group and how
they are related to each other. He also notices the interrelations of
different groups, and the position of each group in the total series.
All this is quite different from a mere droning along through the
items of the list; it is much more active, and much more observant.

Very interesting are the various ways in which the learner attacks a
list of nonsense syllables, numbers, or disconnected words. He goes to
work something like the cat trying to escape from a strange cage. He
proceeds by a sort of trial and error observation; he keeps looking
for something about the list that will help to fix it. He sees
something that promises well for a moment, then gives it up because he
sees something better. He notices positions, i.e., connects items with
their position in the list. He finds syllables that stand out as
peculiar in some way, being "odd", "fuzzy", smooth, agreeable,
disagreeable, or resembling some word, abbreviation or nickname. He
notes resemblances and contrasts between different syllables. He also
finds groups that resemble each other, or that resemble words.

Besides what he actually finds in the list, he imports _meanings_,
more or less far-fetched, into the list. He may make a rhythmical line
of verse out of it; he may make a story out of it. In short, he both
explores the list as it stands and manipulates it into some shape that
promises to be rememberable.

His line of attack differs according to the particular test that is
later to be made of his memory. Suppose he is shown a number of
pictures, with the understanding that later those now shown are to be
mixed with others, and that he must then pick out those now
shown--then he simply examines each picture for something
characteristic. But {336} suppose each picture is given a name, and he
must later tell the name of each--then he seeks for something in the
picture that can be made to suggest its name. Or suppose, once more,
that the pictures are spread out before him in a row, and he is told
that they will later be mixed and he be required to rearrange them in
the same order in which they are now shown--then he seeks for
relationships between the several pictures. His process of memorizing,
always observant, exploratory and manipulatory, differs in detail
according to the memory task that he expects later to perform.

For another example, suppose an experiment is conducted by the method
of "paired associates". The subject is handed a list of pairs of
words, such as

  soprano     emblem
  grassy      concise
  nothing     ginger
  faraway     kettle
  shadow      next
  mercy       scrub
  hilltop     internal
  recite      shoestring
  narrative   thunder
  seldom      harbor
  jury        eagle
  windy       occupy
  squirm      hobby
  balloon     multiply
  necktie     unlikely
  supple      westbound
  obey        inch
  broken      relish
  spellbound  ferment
  desert      expect

He must learn to respond with the second word of each pair when the
first word of the pair is given. What he does, in learning this
lesson, is to take each pair of words as a unit, and try to find
something in the pair that shall make it a firm unit. It may be simply
the peculiar sound or look of a pair that he notes, or it may be some
connection {337} of meaning. Perhaps the pair suggests an image or a
little story. After a few readings, he has the pairs so well in hand
that he can score almost one hundred per cent., if tested immediately.

But now suppose the experimenter springs a surprise, by asking the
subject, as far as possible, to recite the pairs in order, or to tell,
after completing one pair, what was the first word of the next pair.
The subject can do very little at this, and protests that the test is
not fair, since he "paid no attention to the order of the pairs, but
concentrated wholly on each pair separately". Had he expected to
recite the whole list of pairs in order, he would have noticed the
relationship of successive pairs, and perhaps woven them into a sort
of continued story.

In memorizing _connected passages_ of prose or poetry, the "facts
observed" are the general sense and drift of the passage, the meanings
of the parts and their places in the general scheme, the grammatical
structure of the sentences and phrases, and the author's choice of
particular words. Memorizing here is the same general sort of
observant procedure as with nonsense material, greatly assisted by the
familiar sequences of words and by the connected meaning of the
passage, so that a connected passage can be learned in a fraction of
the time needed to memorize an equally long list of unrelated words.
No one in his senses would undertake to memorize an intelligible
passage by the pure rote method, for this would be throwing away the
best possible aid in memorizing; but you will find students who fail
to take full advantage of the sense, because, reading along passively,
they are not on the alert for general trends and outlines. For fixing
in mind the sense of a passage, the essential thing is to see the
sense. If the student gets the point with absolute clearness, he has
pretty well committed it to memory.

{338}

Short-circuiting.

The peculiarities of words or syllables in a list or passage that is
being memorized, the relationships observed among the parts, and the
meanings suggested or imported into the material, though very useful
in the early stages of memorizing, tend to drop out of mind as the
material becomes familiar. A pair of syllables, "lub--mer", may have
first been associated by turning them into "love mother", but later
this meaning fades out, and the two syllables seem simply to belong
together in their own right. A pair of words, like "seldom--harbor",
that were first linked together by the intermediary thought of a boat
that seldom came into the harbor, become directly bound together as
mere words. A short-circuiting occurs, indirect attachments giving way
to direct. Even the outline and general purpose of a connected passage
may fade out of mind, when the passage becomes well learned, so that
it may be almost impossible for a schoolboy, who has learned his
little speech by heart, to deliver it with any consciousness of its
real meaning. A familiar act flattens out and tends to become
automatic and mechanical.


Economy in Memorizing

Memorizing is a form of mental work that is susceptible of management,
and several principles of scientific management have been worked out
that may greatly assist in the learning of a long and difficult
lesson. The problem has been approached from the angle of economy or
efficiency. Suppose a certain amount of time is allowed for the study
of a lesson, how can this time be best utilized?

The first principle of economy has already been sufficiently
emphasized: observant study, directed towards the finding of
relationships and significant facts, is much more efficient than mere
dull repetition.

{339}

The value of recitation in memorizing.

"Recitation" here means reciting to oneself. After the learner has
read his lesson once or twice, he may, instead of continuing simply to
read it, attempt to recite it, prompting himself without much delay
when he is stuck, and verifying his recitation by reference to the
paper. The question is whether this active reciting method of study is
or is not economical of time in memorizing, and whether or not it
fixes the lesson durably in memory. The matter has been thoroughly
tested, and the answer is unequivocally in favor of recitation. The
only outstanding question is as to how soon to start attempting to
recite, and probably no single answer can be given to this question,
so much depends on the kind of material studied, and on peculiarities
of the individual learner. Where the sense rather than the exact
wording of a lesson has to be learned, it is probably best to recite,
in outline, after the first reading, and to utilize the next reading
for filling in the outline.

The results of one series of experiments on this matter are summarized
in the adjoining table.


THE VALUE OF RECITATION IN MEMORIZING (from Gates)

Material studied   16 nonsense syllables       5 short biographies,
                                               totalling about 170 words

                  Per cent, remembered          Per cent. remembered

                 immediately   after 4 hours    immediately   after 4 hours


All time devoted
to reading             35           15              35            16

1/5 of time devoted
to recitation          50           26              37            19

2/5 of time devoted
to recitation          54           28              41            25

3/5 of time devoted
to recitation          57           37              42            26

4/5 of time devoted
to recitation          74           48              42            26


  The time devoted to study was in all cases 9 minutes, and this time
  was divided between reading and recitation in different proportions
  as stated in the first column at the left. Reading down the next
  column, {340} we find that when nonsense syllables were studied and
  the test was conducted immediately after the close of the study
  period, 35 per cent. were remembered when all the study time had
  been devoted to reading, 50 per cent, when the last 1/5 of the study
  time had been devoted to recitation, 54 per cent when the last 2/5
  of the time had been devoted to recitation; and so on. The next
  column shows the per cents. remembered four hours after the study
  period. Each subject in these experiments had before him a sheet of
  paper containing the lesson to be studied, and he simply read it
  till the experimenter gave a signal to recite, after which the
  subject recited the lesson to himself as well as he could, prompting
  himself from the paper as often as necessary, and proceeded, thus
  till the end of the study period. The subjects in these particular
  experiments were eighth grade children; adult subjects gave the same
  general results.


Three facts stand out from the table: (1) Reading down the columns, we
see that recitation was always an advantage. (2) The advantage was
more marked in the test conducted four hours after study than in the
test immediately following the study. To be sure, there is always a
falling off from the immediate to the later test; there is bound to be
some forgetting when the lesson has been studied for so short a time
as here; but the forgetting proceeds more slowly after recitation than
after all reading. Recitation fixes the matter more durably. (3) The
advantage of recitation is less marked in the meaningful material than
in case of nonsense syllables, though it is marked in both cases. The
reason is that meaningful material can better be read observantly,
time after time, than is possible with nonsense material. Continued
reading of nonsense material degenerates into a mere droning, while in
repeatedly reading meaningful material the learner who is keenly
interested in mastering the passage is sure to keep his mind ahead of
his eyes to some extent, so that his reading becomes half recitation,
after all.

Whence comes the advantage of recitation? It has a twofold advantage:
it is more stimulating, and it is more satisfying. When you know you
are going to attempt recitation at once, you are stimulated to observe
positions, peculiarities, relationships, and meanings, and thus your
study {341} goes on at a higher level than when the test of your
knowledge is still far away, with many readings still to come. You are
also stimulated to manipulate the material, by way of grouping and
rhythm.

On the side of satisfaction, recitation shows you what parts of the
lesson you have mastered and gives you the glow of increasing success.
It shows you exactly where you are failing and so stimulates to extra
attention to those parts of the lesson. It taps the instincts of
exploration, manipulation, and mastery much more effectively than
continued re-reading of the same lesson can do. The latter becomes
very uninteresting, monotonous and fatiguing.

Perhaps, after all, the greatest advantage of reciting is that it
makes you do, in learning, the very act that you have later to perform
in the test; for what you have finally to do is to recite the lesson
without the book. When reading, you are doing something different; and
if it were altogether different, it probably would not help you at all
towards success in the test. But since intelligent reading consists
partly in anticipating and outlining as you go, it is a sort of half
recitation, it is halfway doing what you are trying to learn to do.
Memorizing consists in performing an act, now, with assistance, that
you later wish to perform without assistance; and recitation first
stimulates you to fashion the act conformably to the object in view,
and then exercises you in performing that act.


Spaced and unspaced repetition.

Another question on the economical management of memorizing: Is it
better to keep steadily going through the lesson till you have it, or
to go through it at intervals? If you were allowed a certain time, and
no more, in which to prepare for examination on a certain memory
lesson, how could the study time be best distributed? This question
also has received a very definite answer.

{342}

Spaced repetitions are more effective than unspaced. In an experiment
of Pieron, a practised subject went through a list of twenty numbers
with an interval of only thirty seconds between readings, and needed
eleven readings to master the list. But a similar list, with
five-minute intervals, was mastered in six readings; and the number of
readings went down to five with an interval of ten minutes, and
remained the same for longer intervals up to two days. With this
particular sort of lesson, then, ten minutes was a long enough
interval, and two days not too long, to give the greatest economy of
time spent in actual study.

In a somewhat different experiment in another laboratory, lists of
nonsense syllables were studied either two, four, or eight times in
immediate succession, and this was repeated each day till a total of
twenty-four readings had been given to each list; then, one day after
the last reading of each list, the subjects were tested as to their
memory of it. The result appears in the adjoining table.


EFFECT OF SPACED STUDY ON ECONOMY OF MEMORIZING (From Jost)

  Distribution of
  the 24 readings                 Total score    Total score
                                  of Mr. B.      of Mr. M.
  8 readings a day for  3 days        18            7

  6 readings a day for  4 days        39           31

  2 readings a day for 12 days        58           55



The widest distribution gave the best score. Undoubtedly, then, if you
had to memorize a poem or speech, you would get better value for time
spent if you read it once or twice at a time, with intervals of
perhaps a day, than if you attempted to learn it at one continuous
sitting. What exact spacing would give the very greatest economy would
depend on the length and character of the lesson.

Spaced study also fixes the matter more durably. Every student knows
that continuous "cramming" just before an {343} examination, while it
may accomplish its immediate purpose, accomplishes little for
permanent knowledge.

When we say that spaced repetitions give best results in memorizing,
that does not mean that study generally should be in short periods
with intervals of rest; it says nothing one way or the other on that
question. The probability is, since most students take a certain time
to get well "warmed up" to study, that fairly long periods of
consecutive study would yield larger returns than the same amount of
time divided into many short periods. What we have been saying here is
simply that repetition of the _same material_ fixes it better in
memory, when an interval (not necessarily an empty interval) elapses
between the repetitions.


Whole versus part learning.

In memorizing a long lesson, is it more economical to divide it into
parts, and study each part by itself till mastered, or to keep the
lesson entire and always go through the whole thing? Most of us would
probably guess that study part by part would be better, but
experimental results have usually been in favor of study of the whole.

If you had to memorize 240 lines of a poem, you would certainly be
inclined to learn a part at a time; but notice the following
experiment. A young man took two passages of this length, both from
the same poem, and studied one by the whole method, the other by the
part method, in sittings of about thirty-five minutes each day. His
results appear in the table.

LEARNING PASSAGES OF 240 LINES, BY WHOLE AND PART METHODS
(Pyle and Snyder)

  Method of study                Number of days     Total number of
                                   required        minutes required

  30 lines memorized per day,
  then whole reviewed till it
  could be recited                      12              431

  3 readings of whole per day
  till it could be recited              10              348


{344}

Here there was an economy of eighty-three minutes, or nearly twenty
per cent., by using the whole method as against the part method.
Similar experiments have regularly given the same general result.

However, the matter is not quite so simple, as, under certain
conditions, the results tend the other way. Let us consider a very
different type of learning test. A "pencil maze", consisting of
passages or grooves to be traced out with a pencil, while the whole
thing was concealed from the subject by a screen, was so arranged that
it could be divided into four parts and each part learned separately.
Four squads of learners were used. Squads A and B learned the maze as
a whole, squads C and D part by part. Squads A and C learned by spaced
trials, two trials per day. Squad B learned the whole thing at one
sitting; while squad D, which came off best of all, learned one part a
day for four days, and on the fifth day learned to put the parts
together. The results appear in the adjoining table, which shows the
average time required to master the maze by each of the four methods.


PART AND WHOLE LEARNING, SPACED AND UNSPACED,
IN THE PENCIL MAZE (From Pechstein)

                         Spaced trials      Unspaced trials

Whole learning            A  641 seconds     B 1250 seconds

Part learning             C 1220 seconds     D  538 seconds


When the trials were spaced, the whole method was much the better; but
when the trials were bunched, the part method was much the better;
and, on the whole, the unspaced part learning was the best of all.
Thus the result stands in apparent contradiction with two accepted
laws: that of the advantage of spaced learning, and that of the
advantage of whole learning.

This contradiction warns us not to accept the "laws" {345} too
blindly, but rather to analyze out the factors of advantage in each
method, and govern ourselves accordingly. Among the factors involved
are the following four:

(1) The factor of interest, confidence and visible accomplishment--the
emotional factor, we might call it. This is on the side of part
learning, especially with beginners, who soon feel out of their depth
when wading into a long lesson, and lose hope of ever learning it in
this way. This factor is also largely on the side of unspaced as
against spaced learning, when the part studied is of moderate length
and when there are recitations to keep up the interest; for when the
learner sees he is getting ahead, he would rather keep right on than
wait for another day to finish. To have a task that you can hope to
accomplish at once, and to attack it with the intention of mastering
it at once, is very stimulating.

(2) The factor of recency, of "striking while the iron is hot". When
an act has just been successfully performed it can easily be repeated,
and when a fact has just been observed it can readily be put to use.
This factor is clearly on the side of unspaced learning; and it is
also on the side of part learning, since by the time you have gone
through the whole long lesson and got back to where you are now, the
recency value of what you have just now accomplished will have
evaporated.

(3) The factor of meaning, outlining and broad relationships. This is
on the side of whole learning, for it is when you are going through
the whole that you catch its general drift, and see the connections of
the several parts and their places in the whole. This factor is so
important as to outweigh the preceding two in many cases, especially
with experienced learners dealing with meaningful material. Even if
you should prefer the part method, you would be wise to begin by a
careful survey of the whole.

{346}

(4) The factor of permanency. This is something "physiological", and
it is on the side of spaced learning. The muscles profit more by
exercise with intervals of rest than by a large amount of continuous
exercise, and no athlete would think for a moment of training for a
contest of strength by "cramming" for it. Apparently the neurones obey
the same law as the muscles, and for that reason spaced learning gives
more durable results than unspaced.


Unintentional Learning

What we have been examining is intentional memorizing, with the "will
to learn" strongly in the game. The assertion has sometimes been made
that the will to learn is necessary if any learning is to be
accomplished. We must look into this matter, for it has an important
bearing on the whole question of the process of learning.

There is a famous incident that occurred in a Swiss psychological
laboratory, when a foreign student was supposed to be memorizing a
list of nonsense syllables. After the list had been passed before him
many times without his giving the expected signal that he was ready to
recite, the experimenter remarked that he seemed to be having trouble
in memorizing the syllables. "Oh! I didn't understand that I was to
learn them", he said, and it was found that, in fact, he had made
almost no progress towards learning the list. He had been observing
the separate syllables, with no effort to connect them into a series.

Another incident: subjects were put repeatedly through a "color naming
test", which consisted of five colors repeated in irregular order, the
object being to name the one hundred bits of color as rapidly as
possible. After the subjects had been through this test over two
hundred times, you would think they could recite it from memory; but
not {347} at all! They had very little memory of the order of the bits
of color. Their efforts had been wholly concentrated upon naming the
bits as seen, and not in connecting them into a series that could be
remembered.

The experiment described a few pages back on "paired associates" is
another case in point. The subjects memorized the pairs, but made no
effort to connect the pairs in order, and consequently were not able
later to remember the order of the pairs.

Many somewhat similar experiments have been performed, with the object
of measuring the reliability of the testimony of eye-witnesses; and it
has been found that testimony is very unreliable except for facts that
were specifically noted at the time. Enact a little scene before a
class of students who do not suspect that their memory of the affair
is later to be tested, and you will find that their memory for many
facts that were before their eyes is hazy, absent, or positively
false.

These facts all emphasize the importance of the will to learn. But let
us consider another line of facts. An event occurs before our eyes,
and we do notice certain facts about it, not with any intention of
remembering them later, but simply because they arouse our interest;
later, we recall such facts with great clearness and certainty. Or, we
hear a tune time after time, and gradually come to be able to sing it
ourselves, without ever having attempted to memorize it. Practically
all that the child learns in the first few years of his life, he
learns without any "will to learn".

What is the difference between the case where the will to learn is
necessary, and the case where it is unnecessary? The difference is
that in the one case we observe facts for the purpose of committing
them to memory, and in the other case we observe the facts without any
such intention. In both cases we remember what we have definitely
observed, {348} and fail to remember what we have not observed.
Sometimes, to be sure, it is not so much observation as doing that is
operative. We may make a certain reaction with the object of learning
it so as to make it later, or we may make the reaction for some other
reason; but in either case we learn it.

What is essential, then, is not the will to learn, but the doing and
observing. The will to learn is sometimes important, as a directive
tendency, to steer doing and observing into channels relevant to the
particular memory task that we need to perform. But committing to
memory seems not to be any special form of activity; rather, it
consists of reactions that also occur without any view to future
remembering. Not only do we learn _by_ doing and observing, but doing
and observing _are_ learning.


Retention

We come now to the second of our four main problems, and ask how we
retain, or carry around inside of us, what we have learned. The answer
is, not by any process or activity. Retention is a resting state, in
which a learned reaction remains until the stimulus arrives that can
arouse it again. We carry around with us, not the reaction, but the
machinery for making the reaction.

Consider, for example, the retention of motor skill. A boy who has
learned to turn a handspring does not have to keep doing it all the
time in order to retain it. He may keep himself in better form by
reviewing the performance occasionally, but he retains the skill even
while eating and sleeping. The same can be said of the retention of
the multiplication table, or of a poem, or of knowledge of any kind.
The machinery that is retained consists very largely in brain
connections. Connections formed in the process of {349} learning
remain behind in a resting condition till again aroused to activity by
some appropriate stimulus.

But the machinery developed in the process of learning is subject to
the wasting effects of time. It is subject to the law of "atrophy
through disuse". Just as a muscle, brought by exercise into the pink
of condition, and then left long inactive, grows weak and small, so it
is with the brain connections formed in learning. With prolongation of
the condition of rest, the machinery is less and less able to
function, till finally all retention of a once-learned reaction may be
lost.

But _is_ anything once learned ever completely forgotten and lost?
Some say no, being strongly impressed by cases of recovery of memories
that were thought to be altogether gone. Childhood experiences that
were supposed to be completely forgotten, and that could not at first
be recalled at all, have sometimes been recovered after a long and
devious search. Sometimes a hypnotized person remembers facts that he
could not get at in the waking state. Persons in a fever have been
known to speak a language heard in childhood, but so long disused as
to be completely inaccessible in the normal state. Such facts have
been generalized into the extravagant statement that nothing once
known is ever forgotten. For it is an extravagant statement. It would
mean that all the lessons you had ever learned could still be recited,
if only the right stimulus could be found to arouse them; it would
mean that all the lectures you ever heard (and attended to) are still
retained, that all the stories you ever read are still retained, that
all the faces you ever noticed are still retained, that all the scenes
and happenings that ever got your attention could still be revived if
only the right means were taken to revive them. There is no evidence
for any such extreme view.

The modern, scientific study of this matter began with {350}
recognizing the fact that there are _degrees of retention_, ranging
all the way from one hundred per cent, to zero, and with the invention
of methods of measuring retention. Suppose you have memorized a list
of twenty numbers some time ago, and kept a record of the time you
then took to learn it; since when you have not thought of it again.


[Illustration: Fig. 53.--(From Ebbinghaus.) The curve of forgetting.
The curve sinks at first rapidly, and then slowly, from the 100 per
cent line towards the zero line, 100 per cent. here meaning perfect
retention, and 0 no retention.]


On attempting now to recite it, you make no headway and are inclined
to think you have entirely forgotten it. But, finding the list again,
you _relearn_ it, and probably find that your time for relearning is
less than the original learning time--unless the lapse of time has run
into months. Now consider--if no time at all were needed for
relearning, because the list could be recited easily without, your
retention would be one hundred per cent. If, on the contrary, it took
you just as long now to relearn as it did originally to learn, the
retention would be zero. If it takes you now two-thirds as long to
relearn as it originally took to learn, then {351} one-third of the
work originally done on the list does not have to be done over, and
_this saving is the measure of retention_.

By the use of this method, the curve of retention, or curve of
forgetting, as it is also called, has been determined. It is a curve
that first goes down steeply, and then more and more gradually, till
it approximates to zero; which means that the loss of what has been
learned proceeds rapidly at first and then more and more slowly.

The curve of forgetting can be determined by other methods besides the
saving method--by the recall method or by the recognition method; and
data obtained by these methods are given in the adjoining tables. It
will be seen that the different methods agree in showing a curve that
falls off more rapidly at first than later. More is lost in the first
hour than in the second hour, and more in the first week than in the
second week. Few of the experiments have been continued long enough to
bring the curve actually to the zero line, but it has come very close
to that line in tests conducted after an interval of two to four
months.


PER CENT. OF WORDS RECOGNIZED AT DIFFERENT INTERVALS AFTER BEING SEEN
(From Strong)

  Interval between       Per cent. recognized with
  exposure and test      certainty and correctness

   15 secs.               84

    5 min.                73

   15 min.                62

   30 min.                58

    1 hour                56

    2 hours               50

    4 hours               47

    8 hours               40

   12 hours               38

    1 day                 29

    2 days                24

    4 days                19

    7 days                10


  The subject read a list of 20 disconnected words once through,
  giving careful attention to each word. Immediately at the close of
  the reading he performed an example in mental arithmetic, to prevent
  his reviewing the list of words mentally. After an interval, he was
  shown these {352} twenty words mixed with twenty others, and had to
  pick out those he surely recognized as having been shown before.
  Many lists were used, for testing after the different intervals.
  Five adult subjects took part in the experiment, and in all 15 lists
  were used with each interval; the per cents. given in the table are
  the averages for the 15 lists.


  THE PER CENT. OF ERROR IN RECALLING DETAILS OF A
  PICTURE AFTER DIFFERENT INTERVALS OF TIME
  (From Dallenbach)

  Time of test              Per cent, of error      Per cent of error
                            in spontaneous          in answering
                            recall                  questions regarding
 		                                    the picture

  Immediately after exposure     10                      14

  After  5 days                  14                      18

  After 15 days                  18                      20

  After 46 days                  22                      22


  The picture was placed in the subject's hands, and he examined it
  for one minute, at the end of which time he wrote down as complete a
  description of the picture as possible, and then answered a set of
  sixty questions covering all the features of the picture. After five
  days he was retested in the same way, and again after fifteen days,
  etc. In one respect this is not a typical memory experiment, since
  the test after five days would revive the subject's memory of the
  picture and slacken the progress of forgetting. The experiment
  corresponds more closely to the conditions of ordinary life, when we
  do recall a scene at intervals; or it corresponds to the conditions
  surrounding the eye-witness of a crime, who must testify regarding
  it, time after time, before police, lawyers and juries. However, the
  subjects in this experiment realized at the time that they were to
  be examined later, and studied the picture more carefully than the
  eye-witness of a crime would study the event occurring before his
  eyes; so that the per cent. of error was smaller here than can be
  expected in the courtroom.


It must be understood that this classical curve of forgetting only
holds good, strictly, for material that has _barely_ been learned.
Reactions that have been drilled in thoroughly and repeatedly fall off
very slowly at first, and the further course of the curve of
forgetting has not been accurately followed in their case. A typist
who had spent perhaps two hundred hours in drill, and then dropped
typewriting for a year, recovered the lost ground in less than an hour
of fresh practice, so that the retention, as measured by the saving
method, was over ninety-nine per cent.

Somewhat different from the matter of the curve of forgetting is the
question of the _rate of forgetting_, as {353} dependent on various
conditions. The rate of forgetting depends, first, on the thoroughness
of the learning, as we have just seen. It depends on the kind of
material learned, being very much slower for meaningful than for
nonsense material, though both have been learned equally well. Barely
learned nonsense material is almost entirely gone by the end of four
months, but stanzas of poetry, just barely learned, have shown a
perceptible retention after twenty years.

Very fortunately, the principles of economy of memorizing hold good
also for retention. Forgetting is slower when relationships and
connections have been found in the material than when the learning has
been by rote. Forgetting is slower after active recitation than when
the more passive, receptive method of study has been employed.
Forgetting is slower after spaced than after unspaced study, and
slower after whole learning than after part learning.

An old saying has it that quick learning means quick forgetting, and
that quick learners are quick forgetters. Experiment does not wholly
bear this out. A lesson that is learned quickly because it is clearly
understood is better retained than one which is imperfectly understood
and therefore slowly learned; and a learner who learns quickly because
he is on the alert for significant facts and connections retains
better than a learner who is slow from lack of such alertness. The
wider awake the learner, the quicker will be his learning and the
slower his subsequent forgetting; so that one is often tempted to
admonish a certain type of studious but easy-going person, "for
goodness' sake not to dawdle over his lessons", with any idea that the
more time he spends with them the longer he will remember them. More
gas! High pressure gives the biggest results, provided only it is
directed into high-level observation, and does not simply generate
fear and worry and a rattle-brained frenzy of rote learning.

{354}

Recall

Having committed something to memory, how do we get it back when we
want it? To judge from such simple cases as the animal's performance
of a previously learned reaction, all that is necessary is a
_stimulus_ previously linked with the response. How, for example,
shall we get the cat to turn the door-button, this being an act that
the cat has previously learned? Why, we put the cat into the same
cage, i.e., we supply the stimulus that has previously given the
reaction, and trust to it to give the same reaction again. The
learning process has attached this reaction to this stimulus. Now can
we say the same regarding material committed to memory by the human
subject? Is recall a species of learned reaction that needs only the
linked stimulus to arouse it?

If you have learned and still retain a list of numbers or syllables,
you can recite it on thinking of it, on hearing words that identify it
in your mind, or on being given the first few items in the list as a
start. The act of reciting the list became linked, during the
learning, with the thought of the list, with words signifying this
particular list, and with the first items of the list; therefore,
these stimuli can now arouse the reaction of reciting the list. As you
advance into the list, reciting it, the parts already recited act as
stimuli to keep you going forward. In the same way, if you have
memorized Hamlet's soliloquy, this title serves as the stimulus to
make you recall the beginning of the speech and that in turn calls up
the next part and so on; or, if you have analyzed the speech into an
outline, the title calls up the outline and the outline acts as the
stimulus to call up the several parts that were attached to the
outline in the process of memorization. When one idea calls up
another, the first acts as a stimulus and the second is a {355}
response previously attached to this stimulus. In general, then,
recall is a learned response to a stimulus.

There is an exceptional case, where recall seems to occur without any
stimulus. This form of recall goes by the name of _perseveration_, and
a good instance of it is the "running of a tune in the head", shortly
after it has been heard. Another instance is the vivid flashing of
scenes of the day before the "mind's eye" as one lies in bed before
going to sleep. It appears as if the sights or sounds came up of
themselves and without any stimulus. Possibly there is some vague
stimulus which cannot itself be detected. Only a slight stimulus would
be needed, because these recent and vivid experiences are so easily
aroused.


Difficulties in recall.

Sometimes recall fails to materialize when we wish it and have good
reason for expecting it. We know this person's name, as is proved by
the fact that we later recall it, but at the moment we cannot bring it
up. We know the answer to this examination question, but in the heat
of the examination we give the wrong answer, though afterwards the
right answer comes to mind. This seldom happens with thoroughly
learned facts, but frequently with facts that are moderately well
known. Some sort of inhibition or interference blocks recall.

One type of interference is emotional. Fear may paralyze recall.
Anxious self-consciousness, or stage fright, has prevented the recall
of many a well-learned speech, and interfered with the skilful
performance of many a well-trained act.

Distraction is an interference, since it keeps the stimulus from
exerting its full effect. Sometimes the stimulus that is present has
been linked with two or more responses, and these get in each other's
way; as you will sometimes hear a speaker hesitate and become confused
from having two ways {356} of expressing the same thought occur to him
at almost the same instant.


Helps in recall.

There are no sure rules for avoiding these intricate interferences;
and, in general, recall being a much less manageable process than
memorizing, we do not have anything like the same mass of practical
information regarding it. One or two suggestions have some value,
however.

(1) Give the stimulus a good chance. Look squarely at the person whose
name you wish to recall, avoiding doubt as to your ability to recall
it; for doubt is itself a distraction. Put yourself back into the time
when you formerly used this person's name. In extemporaneous speaking,
go ahead confidently, avoid worry and self-consciousness, and, full of
your subject, trust to your ideas to recall the words as needed. Once
carried away with his subject, a speaker may surprise himself by his
own fluency.

(2) Drop the matter for a while, and come back to it afresh.
Sometimes, when you cannot at once recall a name, it does no good to
keep doggedly hunting, while half an hour later you get it without the
least trouble. The explanation of this curious phenomenon is found in
interference and the dying out of interference. At your first attempt
to recall the name, you simply got on the wrong track, and thus gave
this wrong track the "recency" advantage over the right track; but
this temporary advantage fades out rapidly with rest and leaves the
advantage with the track most used in the past.

The rule to drop a matter when baffled and confused, and take it up
again when fresh, can be used in more complex cases than hunting for a
name. When, in trying to solve any sort of problem, you find yourself
in a rut, about the only escape is to back off, rest up, and make an
entirely fresh start.

{357}

Recognition

The fourth question propounded at the beginning of the chapter, as to
how we can know that the fact now recalled is what we formerly
committed to memory and now wish to recall, is part of the larger
question of how we recognize. What we recognize includes not only
facts recalled, but also facts not recalled but presented a second
time to the senses. Recognition of objects seen, heard, touched, etc.,
is the most rudimentary form of memory. The baby shows signs of
recognizing persons and things before he shows signs of recall. A
little later, he recognizes and understands words before he begins to
speak (recall) them; and everybody's vocabulary of recognized words
remains much greater than his speaking vocabulary. We recognize faces
that we could not recall, and names that we could not recall. In
short, recognition is easier than recall.

Consequently any theory of recognition that makes it depend on recall
can scarcely be correct. One such theory held that an object is
recognized by recalling its original setting in past experience; an
odor would be recognized by virtue of recalling the circumstances
under which it was formerly experienced. Now sometimes it does happen
that an odor which seems familiar, but cannot be identified, calls up
a past experience and thus is fully recognized; but such "indirect
recognition" is not the usual thing, for direct recognition commonly
takes place before recall of the past experience has time to occur.
You see a person, and know him at once, though it may require some
moments before you can recall where and when you have seen him before.

Recognition may be more or less complete. At its minimum, it is simply
a "feeling of familiarity" with the object; at its maximum it is
locating the object precisely in your autobiography. You see a man,
and say, "He looks {358} familiar, I must have seen him somewhere",
and then it dawns on you, "Oh! yes, now I know exactly who he is; he
is the man who . . ." Between these extremes lie various degrees of
recognition. This man seems to be some one seen recently, or a long,
long time ago, or at the seashore, or as a salesman in a store; or as
some one you looked up to, or felt hostility towards, or were amused
at; and often these impressions turn out to be correct, when you
succeed in fully recognizing the person. These impressions resemble
the first signs of recognition in the baby's behavior; you say that
the baby remembers people because he smiles at one who has pleased him
before, and shrinks from one who has displeased him.


Recognition described in terms of stimulus and response.

Recognition is a form of learned response, depending on previous
reaction to the object recognized. To recognize an object is to
respond to it as we responded before--except for the feeling of
familiarity, which could not occur the first time we saw the object.
But notice this: though the object is the same identical object it was
before, it may have changed somewhat. At least, its setting is
different; this is a different time and perhaps a different place, and
the circumstances are bound to be more or less different. In spite of
this difference in the situation, we make the same response as before.

Now, the response we made to the object in its original setting was a
response to the whole situation, object _plus_ setting; our response
to the object was colored by its setting. When we now recognize the
object, we make the same response to the object in a different
setting; the response originally called out by the object _plus_ its
setting is now aroused by the object alone. Consequently we have an
uneasy feeling of responding to a situation that is not present. {359}
This uneasy feeling is the feeling of familiarity in its more haunting
and "intriguing" form.

We see some one who seems familiar and who arouses a hostile attitude
in us that is not accounted for in the least by his present actions.
We have this uneasy feeling of responding to a situation that is not
present, and cannot rest till we have identified the person and
justified our hostile attitude.

Or, we see some one who makes us feel as if we had had dealings with
him before in a store or postoffice where he must have served us; we
find ourselves taking the attitude towards him that is appropriate
towards such a functionary, though there is nothing in his present
setting to arouse such an attitude. Or, we see some one in the city
streets who seems to put us back into the atmosphere of a vacation at
the seashore, and by searching our memory we finally locate him as an
individual we saw at such and such a resort. At other times, the
feeling of familiarity is rather colorless, because the original
situation in which the person was encountered was colorless; but we
still have the feeling of responding to something that is not present.
We make, or start to make, the same response to the person that we
originally made to him _plus_ his setting, and this response to
something that is not there gives the feeling of familiarity.

When we see the same person time after time in the same setting, as
when we go into the same store every morning and buy a paper from the
same man, we cease to have any strong feeling of familiarity at sight
of him, the reason being that we are always responding to him in the
same setting, and consequently have no feeling of responding to
something that is not there. But if we see this same individual in a
totally different place, he may give us a queer feeling of
familiarity. When we see the same person time after time {360} in
various settings, we end by separating him from his surroundings and
responding to him alone, and therefore the familiarity feeling
disappears.

Complete recognition, or "placing" the object, involves something more
than these feelings and rudimentary reactions. It involves the recall
of a context or scheme of events, and a fitting of the object into the
scheme.


Memory Training

The important question whether memory can be improved by any form of
training breaks up, in the light of our previous analysis, into the
four questions, whether memorizing can be improved, whether the power
of retention can be improved, whether recall can be improved, and
whether recognition can be improved. As to recognition, it is
difficult to imagine how to train it; the process is so elusive and so
direct. It has been found, however, that practice in recognizing a
certain class of objects improves one's standards of judgment as to
whether a feeling of familiarity is reliable or not; it enables one to
distinguish between feelings that have given correct recognitions and
the vaguer feelings that often lead one astray.

As to recall, certain hints were given above as to the efficient
management of this process, and probably practice in recalling a
certain sort of facts, checked up by results, would lead to
improvement.

As to retention, since this is not a performance but a resting state,
how could we possibly go about to effect an improvement? One
individual's brain is, to be sure, more retentive than another's; but
that seems a native trait, not to be altered by training.

On the other hand, the process of committing to memory, being a
straightforward and controllable activity, is {361} exceedingly
susceptible to training, and it is there, for the most part, that
memory training should be concentrated in order to yield results. It
does yield marked results. In the laboratory, the beginner in learning
lists of nonsense syllables makes poor work of it. He is emotionally
wrought up and uncertain of himself, goes to work in a random way
(like any beginner), perhaps tries to learn by pure rote or else
attempts to use devices that are ill-adapted to the material, and has
a slow and tedious job of it. With practice in learning this sort of
material, he learns to observe suitable groupings and relationships,
becomes sure of himself and free from the distraction of emotional
disturbance, and may even come to enjoy the work. Certainly he
improves greatly in speed of memorizing nonsense syllables. If,
instead, he practises on Spenser's "Faery Queen", he improves in that,
and may cut down his time for memorizing a twelve-line stanza from
fifteen minutes to five. This improvement is due to the subject's
finding out ways of tackling this particular sort of material. He gets
used to Spenser's style and range of ideas. And so it is with any kind
of material; practice in memorizing it brings great improvement in
memorizing that particular material.

Whether practice with one sort of material brings skill that can be
"transferred", or carried over to a second kind of material, is quite
another question. Usually the amount of _transfer_ is small compared
with the improvement gained in handling the first material, or
compared with the improvement that will result from specific training
with the second kind. What skill is transferred consists partly of the
habit of looking for groupings and relationships, and partly in the
confidence in one's own ability as a memorizer. It is really worth
while taking part in a memory experiment, just to know what you can
accomplish after a little training. Most persons who complain of poor
memory would be {362} convinced by such an experiment that their
memory was fundamentally sound. But these laboratory exercises do not
pretend to develop any general "power of memory", and the much
advertised systems of memory training are no more justified in such a
claim. What is developed, in both cases, is skill in memorizing
certain kinds of material so as to pass certain forms of memory test.

One who suffers from poor memory for any special material, as names,
errands, or engagements, probably is not going to work right in
committing the facts to memory; and if he gives special attention to
this particular matter, keeping tab on himself to see whether he
improves, he is likely to find better ways of fixing the facts and to
make great improvement. It was said of a certain college president of
the older day that he never failed to call a student or alumnus by
name, after he had once met the man. How did he do it? He had the
custom of calling each man in the freshman class into his office for a
private interview, during which, besides fatherly advice, he asked the
man personal questions and studied him intently. He was interested in
the man, he formed a clear impression of his personality, and to that
personality he carefully attached the name. Undoubtedly this able
scholar was possessed of an unusually retentive memory; but his memory
for names depended largely on his method of committing them to memory.

Contrast this with the casual procedure of most of us on being
introduced to a person. Perhaps we scarcely notice the name, and make
no effort to attach the name to the personality. To have a good memory
for names, one needs to give attention and practice to this specific
matter. It is the same with memory for errands; it can be specifically
trained. Perhaps the best general hint here is to connect the errand
beforehand in your mind with the {363} place where you should think,
during the day, to do the errand.

Often some little _mnemonic system_ will help in remembering
disconnected facts, but such devices have only a limited field of
application and do not in the least improve the general power of
memory. Some speakers, in planning out a speech, locate each
successive "point" in a corner of the hall, or in a room of their own
house; and when they have finished one point, look into the next
corner, or think of the next room, and find the following point there.
It would seem that a well-ordered discourse should supply its own
logical cues so that such artificial aids would be unnecessary.

In training the memory for the significant facts that constitute the
individual's knowledge of his business in life, the best rule is to
systematize and interrelate the facts into a coherent whole. Thus, a
bigger and stronger stimulus is provided for the recall of any item.
This, along with the principles of "economy" in memorizing, is the
best suggestion that psychology has to make towards memory
improvement.

{364}

EXERCISES

1. In outlining the chapter, regroup the material so as to separate
   the practical applications from the description of memory
   processes. This gives you two main heads: A. Memory processes, and
   B. The training and management of memory. Each of these main heads
   should be divided into four sub-heads: Memorizing, retention, etc.,
   and the information contained in the chapter grouped under these
   sub-heads.

2. Disorders of memory can be classified under the four heads of
   disorders of learning, of retention, of recall and of recognition.
   Where would you place each of the following?

  (a) Aphasia, where, through brain injury, the subject's
      vocabulary is very much reduced.

  (b) The condition of the very old person, who cannot remember
      what has happened during the day, though he still remembers
      experiences of his youth.

  (c) The "feeling of having been there before", in which you have
      a weird impression that what is happening now has happened in
      just the same way before, as if events were simply repeating
      themselves.

  (d) The loss of memory which sometimes occurs after a physical
      or emotional shock, or after a fever, and which passes away
      after a time.

3. How fully can you recall what happened on some interesting
   occasion when you were a child of 5-8 years? Dwell on the
   experience, and see whether you get back more than at first seemed
   possible. Try the same with an experience of five years ago.

4. If a student came to you for advice, complaining of poor memory,
   and said that though he put hours and hours on a lesson and read it
   over many times, still he failed on it, what questions would you
   ask regarding his method of study, and what suggestions would you
   offer?

5. An experiment on memorising lists of numbers. Prepare several
   lists of 20 digits, and shuffle them; draw out one and take your
   time for learning it to the point of perfect recitation. Write an
   introspective account of the process. Repeat with a second list

6. An experiment in memorizing word-pairs. Prepare 20 pairs of
   words as follows: take 20 cards or slips of paper, and write a
   different word on each. Then turn them over, shuffle, and write
   another word on the back of each. Thus, though you may know what
   words you have written, you do not how how they are paired; and now
   your job is to learn the pairs. Note starting time, take the first
   card and look at both {365} sides, and study the pair of words on
   this card for about 5 seconds, passing then to the second card, and
   so on through the pack. Shuffle the pack, take the top card and
   give yourself about 5 seconds to recall the word on the reverse,
   then turning the card over and reading it. Proceed in this way
   through the pack, shuffle again, and repeat. Continue thus till you
   score 100 per cent. Note total time required, and report on process
   of memorizing.

7. Memorizing a series of related words. Prepare a list of 40
   words, as follows: first write the numbers 1 to 40 in a column;
   then write any word for No. 1; for No. 2, write some word closely
   related to No. 1; for No. 3 some word closely related to No. 2; and
   so on. Your list, for example, might begin like this: house, roof,
   chimney, soot, fire, coal, mine, miner, strike, arbitration, etc.
   Having finished writing your list, cover it and see how much of it
   you can recite without further study, and how long it takes you to
   complete the memorizing. Explain the results obtained.

8. Plot the curve of forgetting from the following data, which give
   the per cent, of retention of stanzas of a poem at different
   intervals after the end of memorizing.

     after  1 day  79%
     after  2 days 67%
     after  6 days 42%
     after 14 days 30%
     after 30 days 24%


REFERENCES

Ebbinghaus, _On Memory_, 1885, translated by Ruger and Bussenius,
1918. This is the pioneer experimental study of memory, and is still
worth reading, and is not specially hard reading.

James's chapter on Memory, in Vol. I of his _Principles of
Psychology_, 1890, is still one of the best references, and contains
some important remarks on the improvement of memory.

Of the numerous special studies on memory, mention may be made of that
by Arthur I. Gates, _Recitation as a Factor in Memorizing_, 1917,
which, on pp. 65-104, gives a valuable account of the various devices
used by one who is memorizing.

For the psychology of testimony, see G. M. Whipple's article on "The
Obtaining of Information: Psychology of Observation and Report", in
the _Psychological Bulletin_ for 1918, Vol. 15, pp. 217-248,
especially pp. 233-248. See also a popularly written account of the
matter by Muensterberg, in _On the Witness Stand_, 1908, pp. 15-69.

{366}


CHAPTER XV

ASSOCIATION AND MENTAL IMAGERY

SOMETHING ABOUT THINKING AS RELATED TO MEMORY

Memory plays a part, not only in "memory work", and not only in
remembering particular past experiences, but in all sorts of thinking.
Recall furnishes the raw material for thought. A large share of any
one's daily work, whether it be manual or mental, depends on the
recall of previously learned reactions. Most of the time, though we
are not exactly trying to remember facts committed to memory, we are
recalling what we have previously learned, and utilizing the recalled
material for our present purposes. For example, in conversation we
recall words to express our meaning, and we recall the meanings of the
words we hear. In adding a column of figures, we recall the sums of
the numbers. In cooking a meal, we recall the ingredients of the dish
we wish to prepare, and the location of the various materials and
utensils required for our purpose. In planning a trip, we recall
places and routes. Any sort of problem is solved by means of recalled
facts put together in a new way. A writer in constructing a story puts
together facts that he has previously noted, and any work of the
imagination consists of materials recalled from past experience and
now built into a new composition.


What Can Be Recalled

If recall is so important in thinking and acting, it is worth while to
make a survey of the materials that recall {367} furnishes. In
general, using the term "recall" rather broadly, we say that any
previously learned reaction may be recalled. Writing _movements_ may
be said to be recalled when we write, and speech movements when we
speak. "Higher units", like the word habits and phrase habits of the
telegrapher and typist, are in a broad sense recalled whenever they
are used. The typist does not by any means recall the experience of
learning a higher unit, but he calls into action again the response
that he has learned to make. In the same way, the word habits and
phrase habits of vocal speech are called into action, i.e., recalled,
whenever we speak.

Besides these motor reactions, _tendencies_ to reaction can be
recalled. The attitude of hostility that may have become habitual in
us towards a certain person, or towards a certain task, is called into
activity at the mention of that person or task. The acquired interest
in architecture that we may have formed by reading or travel is
revived by the sight of an ambitious group of buildings. A slumbering
purpose may be recalled into activity by some relevant stimulus.

Observed _facts_ can be recalled, and this is the typically human form
of recall. In animals, we see the recall of tendencies and of learned
movements, but no clear evidence of the recall of observed facts. To
be recalled with certainty, a fact must have been definitely noted
when it was before us. If we have definitely noted the color of a
person's eyes, we are in a position to testify that his eyes are
brown, for example; otherwise, we may say that we think probably his
eyes are brown; because we have certainly noticed that he is dark, and
the dark eyes fit best into this total impression.

We say that a fact is recalled when we think of it without its being
present to the senses. While the original {368} observation of the
fact was a response to a sensory stimulus, the recall of it is a
response to some other stimulus, some "substitute stimulus". When John
is before me, I observe that his eyes are brown in response to a
visual stimulus; but I later recall this fact in response simply to
the name "John", or in response to the question as to what is the
color of John's eyes. I see what a square is by seeing squares and
handling them, and later I get this idea simply in response to the
word "square" in conversation or reading.


Memory Images

Now, can _sensations_ be recalled, can they be aroused except by their
natural sensory stimuli? Can you recall the color blue, or the sound
of a bugle, or the odor of camphor, or the feel of a lump of ice held
in the hand? Almost every one will reply "Yes" to some at least of
these questions. One may have a vivid picture of a scene before the
"mind's eye", and another a realistic sound in the "mind's ear", and
they may report that the recalled experience seems essentially the
same as the original sensation. Therefore, sensory reactions are no
exception to the rule of recall by a substitute stimulus.

A sensation or complex of sensations recalled by a substitute stimulus
is called a "mental image" or a "memory image".

Individuals seem to differ in the vividness or realism of their memory
images--the likeness of the image to an actual sensation--more than in
any other respect. Galton, in taking a sort of census of mental
imagery, asked many persons to call up the appearance of their
breakfast table as they had sat down to it that morning, and to
observe how lifelike the image was, how complete, how adequate in
respect to color, how steady and lasting, and to compare {369} the
image in these respects with the sensory experience aroused by the
actual presence of the scene. Some individuals reported that the image
was "in all respects the same as an original sensation", while others
denied that they got anything at all in the way of recalled sensation,
though they could perfectly well recall definite facts that they had
observed regarding the breakfast table. The majority of people gave
testimony intermediate between these extremes.

Individuals differ so much in this respect that they scarcely credit
each other's testimony. Some who had practically zero imagery held
that the "picture before the mind's eye" spoken of by the poets was a
myth or mere figure of speech; while those who were accustomed to
vivid images could not understand what the others could possibly mean
by "remembering facts about the breakfast table without having any
image of it", and were strongly tempted to accuse them of poor
introspection, if not worse. It is true that in attempting to study
images, we have to depend altogether on introspection, since no one
can objectively observe another person's memory image, and therefore
we are exposed to all the unreliability of the unchecked introspective
method. But at the same time, when you cross-question an individual
whose testimony regarding his imagery is very different from yours,
you find him so consistent in his testimony and so sure he is right,
that you are forced to conclude to a very real difference between him
and yourself. You are forced to conclude that the power of recalling
sensations varies from something like one hundred per cent, down to
practically zero.

Individuals may also differ in the _kind_ of sensation that they can
vividly recall. Some who are poor at recalling visual sensations do
have vivid auditory images, and others who have little of either
visual or auditory imagery call up {370} kinesthetic sensations
without difficulty. When this was first discovered, a very pretty
theory of "imagery types" was built upon it. Any individual, so it was
held, belonged to one or another type: either he was a "visualist",
thinking of everything as it appears to the eyes, or he was an
"audile", thinking of everything according to its sound, or he was a
"motor type", dealing wholly in kinesthetic imagery, or he might, in
rare cases, belong to the olfactory or gustatory or tactile type.


[Illustration: Fig. 54.--Individual differences in mental imagery.
According to the type theory, every individual has a place in one or
another of the distinct groups, visual, auditory, tactile,
kinesthetic, or olfactory. According to the facts, the majority, of
individuals cluster in the middle space, and form a single large
group, though some few are extremely visual, or auditory, etc., in
their imagery. (Figure text: according to the type theory, according to
the facts)]


But the progress of investigation showed, first, that a "mixed type"
must also be admitted, to provide for individuals who easily called up
images of two or more different senses; and, later on, that the mixed
type was the most common. In fact, it is now known to be very unusual
for an individual to be confined to images of a single sense. Nearly
every one gets visual images more easily and frequently than those of
any other sense, but nearly every one has, from time to time,
auditory, kinesthetic, tactile and olfactory images. So that the
"mixed type" is the only real type, the extreme visualist or audile,
etc., being exceptional and not typical.

{371}

Limitations of Imagery

Recalled sensations are commonly inferior to their originals, both in
the enjoyment they afford and in the use that can be made of them.
They are likely to be inferior in several respects.

(1) An image has usually less color, or tone--less body, realism and
full sensory quality--than a sensation aroused by its appropriate
peripheral stimulus. While you may be able to call up a fairly good
image of your absent friend's face, the actual presence of your friend
would be more satisfactory, just as a sensory experience. You may be
able to run over a piece of music "in your head", and if your auditory
imagery is strong you may even run over an orchestral piece, and get
the tone quality of the various instruments; but, after all, such a
mental concert is an imperfect substitute for a real orchestra. You
enjoy a real whiff of the sea more than the best olfactory image you
can summon. There is something lacking in these recalled sensations,
and the trouble seems to be that they are not sensations enough; they
lack sensory body.

(2) Images are apt to be sketchy and lacking in detail, and also
narrow and lacking in background.

(3) Images are apt to be unsteady and fleeting, as compared with
actual sensations. Where the peripheral stimulus, continuing, keeps
the sensation going, the substitute stimulus that recalls a sensation
is not so effective in this respect, any more than in giving body and
detail. In all these respects, an image is less enjoyable and
satisfying than an actual sensation.

(4) On the more practical side, images are inferior to the actual
presence of an object, in that we cannot utilize the image as a source
of new information. {372} We _cannot observe facts_ in the image of a
thing that we have not observed in the actual presence of the thing.

At one of the universities, there is a beautiful library building,
with a row of fine pillars across the front, and the students pass
this building every day and enjoy looking at it. It has long been a
favorite experiment in the psychology classes at that university to
have the students call up an image of the library, and to have them
state how clear their image is, how complete and how vivid. Then they
are asked to count the pillars from their image, and to tell what kind
of capitals the pillars have, and whether the shafts are plain or
fluted. But at this point the students begin to object. "We have never
counted those pillars, and cannot be expected to know the number now."
In fact, few of them give the correct number, and those who have
reported clear and vivid images are little better off in this respect
than those whose images are dim and vague.

The image, then, does not give you facts that you did not observe in
the presence of the object. The substitute stimulus, which now recalls
the image, only recalls responses which you made when the real object
was the stimulus. If you looked at the object simply to get its
general appearance, the general appearance is all you can recall. If
you noted the color of the object, you can probably recall the color.
If you noted such details as the number of pillars, you can recall
these details. But the substitute stimulus that now arouses the image
is by no means the equivalent of the original peripheral stimulus in
making possible a variety of new reactions. Its only linkage is with
reactions actually made by you in response to the real object. The
substitute stimulus, such as the name of a building, became linked
with responses actually made by you, not with responses that you
simply might have made, when the object was present. This important
fact is closely related to the {373} unreliability of testimony that
was mentioned before under the head of "unintentional memory".
[Footnote: See pp. 346-348.] Facts recalled are facts previously
observed.

It is true, of course, that recalled facts can be compared and new
facts be observed by the comparison. We may recall how John looks, and
how James looks, and note the fact, not previously observed, that they
look alike. A great deal can be inferred in this way by a person who
is sitting in his room far from the objects thought about. But this
noting of the relationships of different objects is a very different
matter from observing what is there, in a single object or scene. What
is there can only be observed when you are there.


The Question of Non-Sensory Recall

Many observed facts are not strictly facts of sensation, though
observed by means of the senses. Let us suppose, for an example, that
your attention is caught by the bright green new leaves at the tips of
the branches of an evergreen tree in summer, and that you notice also
the darker green of the older leaves further back along the branches,
and, exploring deeper, find leaves that are dead and brown, while
still further in they have all fallen off, leaving bare branches
reaching back to the trunk; so that you finally "see" how the tree is
constructed, as a hollow cone of foliage supported by an interior
framework of branches. All this has meant a lot of different reactions
on your part, and the final "seeing" of how the tree is constructed
would scarcely be called a sensation, since it has required mental
work beyond that of simply seeing the tree. It is a response
additional to the strictly sensory response of seeing the tree.

Now the question is whether this additional response can be recalled,
without recalling at the same time the primary {374} response of
seeing the tree. Can we recall the fact observed about the tree
without at the same time seeing the tree "in the mind's eye"? Must we
necessarily have an image of the tree when we recall the way the tree
is constructed?

Since getting the general sensory appearance of the tree, and
observing the way it is constructed, are two different responses, it
seems quite conceivable that either fact should be recalled without
the other; and no one doubts that the sensory appearance of the tree
can be recalled without the other observed fact coming up along with
it. But many authorities have held that the non-sensory fact could not
be recalled alone; in other words, they have held that every recalled
fact comes as a sensory image, or with a sensory image. Persons with
ready visual imagery are of course likely to get a visual image with
any fact they may recall. But persons whose visual imagery is hard to
arouse say that they recall facts without any visual image. I who
write these words, being such a person, testify that while I have been
writing and thinking about that tree I have not seen it before my
mind's eye.

It is true, however, that I have had images during this time--auditory
images of words expressing the facts mentioned. Another individual
might have had kinesthetic images instead of either visual or
auditory. But can there be a recall of fact without _any_ sensory
image?

On this question, which has been called the question of "imageless
thought", though it might better be called that of "imageless recall",
controversy has raged and is not yet at rest, so that a generally
accepted conclusion cannot be stated. But the best indications are to
the effect, first, that vague and fleeting images, especially of the
kinesthetic sort, are often present without being detected except by
very fine introspection, some image being pretty sure to come up every
few seconds when we are engaged in silent thought or {375} recall;
but, second, that images are not present every second of the time, and
that at the instant when a non-sensory fact is recalled it is apt to
be alone.


Hallucinations

Since a vivid mental image may be "in all respects the same as an
actual sensation", according to the testimony of some people, the
question arises how, then, an image is distinguished from a sensation.
Well, the image does not usually fit into the objective situation
present to the senses. But if it does fit, or if the objective
situation is lost track of, then, as a matter of fact, the image may
be taken for a sensation.

You see some beautiful roses in the florist's window, and you _smell_
them; the odor fits into the objective situation very well, till you
notice that the shop door is shut and the window glass impervious to
odors, from which you conclude that the odor must have been your
image.

You are lost in thought of an absent person, till, forgetting where
you are, you seem to see him entering the door; he "fits" well enough
for an instant, but then the present situation forces itself upon you
and the image takes its proper place.

You are half asleep, almost lost to the world, and some scene comes
before you so vividly as to seem real till its oddity wakens you to
the reality of your bedroom. Or you are fully asleep, and then the
images that come are dreams and seem entirely real, since contact with
the objective situation has been broken.

Images taken for real things are common in some forms of mental
disorder. Here the subject's hold on objective fact is weakened by his
absorption in his own desires and fears, and he hears reviling voices
and smells suspicious {376} odors or sees visions that are in line
with his desires and fears.

Such false sensations are called "hallucinations". An hallucination is
an image taken for a sensation, a recalled fact taken for a present
objective fact. It is a sensory response, aroused by a substitute
stimulus, without the subject's noticing that it is thus aroused
instead of by its regular peripheral stimulus.


Synesthesia.

Quite a large number of people are so constituted as to hear sounds as
if colored, a deep tone perhaps seeming dark blue, the sound of a
trumpet a vivid red, etc. Each vowel and even each consonant may have
its own special color, which combine to give a complex color scheme
for a word. Numbers also may be colored. This colored hearing is the
commonest form of "synesthesia", which consists in responding to a
stimulus acting on one sense, by sensations belonging to a different
sense. Whether the persons so constituted as to respond in this way
are constituted thus by nature or by experience is uncertain, though
the best guess is that the extra sensations are images that have
become firmly attached to their substitute stimuli during early
childhood.


Free Association

Mental processes that depend on recall are called "associative
processes", since they make use of associations or linkages previously
formed. When some definite interest or purpose steers the associative
processes, we speak of "controlled association", contrasting this with
the "free association" that occurs in an idle mood, when one thought
simply calls up another with no object in view and no more than
fleeting desires to give direction to the sequence of thoughts.

_Revery_ affords the best example of free association. I {377} see my
neighbor's dog out of my window, and am reminded of one time when I
took charge of that dog while my neighbor was away, and then of my
neighbor's coming back and taking the dog from the cellar where I had
shut him up; next of my neighbor's advice with respect to an
automobile collision in which I was concerned; next of the stranger
with whom I had collided, and of the stranger's business address on
the card which he gave me; next comes a query as to this stranger's
line of business and whether he was well-to-do; and from there my
thoughts switch naturally to the high cost of living.

This is rather a drab, middle-aged type of revery, and youth might
show more life and color; but the linkages between one thought and the
next are typical of any revery. The linkages belong in the category of
"facts previously observed". I had previously observed the ownership
of this dog by my neighbor, and this observation linked the dog and
the neighbor and enabled the dog to recall the neighbor to my mind.
Most of the linkages in this revery are quite concrete, but some are
rather abstract, such as the connection between being well-to-do (or
not) and the high cost of living; but, concrete or abstract, they are
connections previously observed by the subject. Sometimes the linkage
keeps the thoughts within the sphere of the same original experience,
and sometimes switches them from one past experience to another, or
even away from any specific past experience to general considerations;
yet always the linkage has this character, that the item that now acts
as stimulus has been formerly combined in observation with the other
item that now follows as the response. One fact recalls another when
the two have been previously observed as belonging together.

But suppose, as is commonly the case, that the fact now present in my
mind has been linked, in different past {378} experiences, with
several different facts. Then two questions demand our attention:
whether all these facts are recalled; and, if not, what gives the
advantage to the fact actually recalled over the others that are not
recalled.

The answer to the first question is plain. The fact first present in
mind does not call up all the associated facts, but usually only one
of them, or at least only one at a time. My neighbor, in the example
given, though previously associated with a dozen other facts, now
calls up but two of these facts, and those two not simultaneously but
one after the other. We see a law here that is very similar to a law
stated under the head of attention. There, we said that of all the
objects before us that might be noticed only one was noticed at a
time; and here we say that of all the objects that might be recalled
to mind by association only one is recalled at a time. Both statements
can be combined into the one general "law of reaction" which was
mentioned before, that of all the responses linked to a given stimulus
(or complex of stimuli) only one is actually aroused at the same
instant, though several may be aroused in succession, provided the
stimulus continues.

In revery, the stimulus usually does not continue. The first fact
thought of gives way to the fact that it recalls, and that to one that
it recalls in turn, and so on, without much dwelling on any fact. But
if we do dwell on any fact--as upon the thought of a certain
person--then this stimulus, continuing to act, calls up in succession
quite a number of associated facts.

If, then, only one of the several facts associated with the stimulus
is recalled at once, our second question presents itself, as to what
are the factors of advantage that cause one rather than another of the
possible responses to occur. The fact first in mind might have called
up any one of several facts, having been linked with each of them in
past {379} experience; and we want to know why it recalls one of these
facts rather than the rest.

The factors of advantage in recall are the factors that determine the
strength of linkage between two facts; and they are:

  the _frequency_ with which the linkage has occurred;
  the _recency_ with which it has occurred; and
  the _intensity_ with which it has occurred.

If I have frequently observed the connection of two facts, the linkage
between them is strong; if I have recently observed their connection,
the linkage between them is strong till the "recency value" dies away;
and if my observation of the connection of the two facts was a vivid
experience, or intense reaction, then, also, the linkage between them
is strong. If these three factors of advantage work together in favor
of the same response, then that response is sure to occur; but if the
three factors pull different ways, we should have to figure out the
balance of advantage before we could predict which of the possible
responses would actually be made. Naturally enough, even the skilful
psychologist is often unable to strike the balance between the three
factors. He does know, however, and all of us know in a practical way,
that strong recency value offsets a lot of frequency; so that a mere
vague allusion to a very recent topic of conversation can be depended
on to recall the right facts to the hearer's mind, even though they
lie outside of his habitual line of interest. "James", by virtue of
frequency, means your brother or friend; but after the lecturer has
been talking about the psychologist James, repetition of this name
infallibly recalls the psychologist to mind.

Besides frequency, recency and intensity, there is, indeed, another
factor to be taken into account; and that is the {380} present state
of the subject's mind. If he is unhappy, unpleasant associations have
the advantage; if happy, pleasant. If he is absorbed in a given
matter, facts related to that matter have the advantage. Frequency,
recency and intensity summarize the _history_ of associations, and
measure their strength as dependent on their history; but the present
state of mind is an additional directive factor, and when it has much
to do with recall, we speak of directed or controlled association.

Before we pass to the topic of controlled association, however, there
is another form of free association, quite different from revery, to
be examined. There is an experiment, called the _free association
test_, in which the subject is given a series of words as stimuli, and
is asked to respond to each word by speaking some other word, the
first that is recalled by the stimulus. No special kind of word need
be given in response, but simply the _first word recalled_. Though
this is called free association, it is controlled to the extent that
the response must be a word, and the result is very different from
revery. Instead of the recall of concrete facts from past experience,
there is recall of words. If you give the subject the stimulus word,
"table", his response is "chair" or "dinner", etc., and often he does
not think of any particular table, but simply of the word. Words are
so often linked one with another that it is no wonder that one recalls
another automatically. What particular word shall be recalled depends
on the frequency, recency and intensity of past linkage.

Though this form of test seems so simple as almost to be silly, it is
of use in several ways. When a large number of stimulus words are
used, and the responses classified, some persons are found to favor
linkages that have a personal significance--"egocentric responses",
these are called--while other persons run to connections that are
{381} impersonal and objective. Thus the test throws some light on the
individual's _habits_ of attention. The test has also a "detective"
use, based upon the great efficacy of the factor of _recency_; you may
be able by it to tell whether an individual has recently had a certain
matter in mind. If he happens to be an individual who has recently
committed some crime, properly selected stimulus words will lead him
to recall the scene of the crime, and thus to make responses that
betray him, unless he checks them and so arouses suspicion by his
hesitation. Another use of the test is for unearthing a person's
emotional "complexes", which of course possess a high _intensity_
value. If the subject shows hesitation and embarrassment in responding
to words referring to money, the indication is that he is emotionally
disturbed over the state of his finances. One person who consulted a
doctor for nervousness made peculiar responses to stimulus words
relating to the family, and was discovered to be much disturbed over
his family's opposition to his projected marriage. The free
association test is useful rather as giving the experienced
psychologist hints to be followed up than as furnishing sure proof of
the contents of the subject's mind.


Controlled Association

There is a controlled association test conducted like this one in free
association, except that the subject is required to respond to each
stimulus word by a word standing in a specified relation to it. To one
series of words he must respond by saying their opposites; to another,
by mentioning a part of each object named; to another series,
consisting of names of countries, he must respond by naming as quickly
as possible the capital of each country named; and there are many
tests of this sort, each dealing with some class of relationships
which, being often observed, are easily handled {382} by a person of
normal intelligence. The intelligent subject makes few errors in such
a test, and responds in very quick time. Indeed, the remarkable fact
is that he takes less time to respond in an easy controlled
association test than in the free association test; which shows that
the "control" acts not simply to limit the response, but also to
_facilitate_ it.

The "control" here is often called by the name of "mental set". It is
a good example of a "reaction tendency". On being told you are to give
opposites, you somehow set or adjust your mental machinery for making
this type of response. The mental set thus thrown into action
facilitates responses of the required type, while inhibiting other
responses that would readily occur in the absence of any directive
tendency. If the word "good" came as a stimulus word in a free
association test, it might easily arouse the responses, "good day",
"good night", "good boy", "good better", and many besides, since all
of these combinations have been frequently used in the past; and the
balance of frequency, recency and intensity might favor any one of
these responses. But when the subject is set for opposites, the
balance of these factors has little force as against the mental set.
The mental set for opposites favors the revival of such combinations
as "new--old", "good--bad", and such others of this class as have been
noted and used in the subject's past experience.

Mental set is a selective factor, a factor of advantage. It does not
supersede the previously formed associations, or work independently of
them, but selects from among them the one which fits the present task.
Does it get in its work after recall has done its part, or before?
Does it wait till recall has brought up a number of responses, and
then pick out the one that fills the bill? No, it often works much too
quickly for that, giving the right response instantly; and
introspection is often perfectly clear that none but the right {383}
response is recalled at all. The selective influence of the mental set
is exerted _before recall_; it facilitates the right recall and
inhibits recall of any but the right response.

In controlled association, as in free association, only one of the
facts previously linked with the stimulus is recalled at a time; but
while in free association the factors of frequency, recency and
intensity of past linkage determine which of the many possible facts
shall be recalled, in controlled association the additional factor of
mental set is present and has a controlling influence in determining
which fact shall be recalled. Thus, in an opposites test, the stimulus
word "good" promptly calls up the pair "good--bad", because the mental
set for opposites gives this response a great advantage over "good
night" and other responses which may have a very strong linkage with
the stimulus word.

The mental set is itself a response to a stimulus. It is an inner
response thrown into activity by some stimulus, such as the stimulus
of being asked to give the opposites of a series of words that are
presently to be shown or spoken. This inner response of getting ready
for the task can be introspectively observed by a person who is new to
this type of test. It may take the form of mentally running over
examples of opposites--or whatever kind of responses are to be called
for--or it may take the form of calling up some image or diagram or
gesture that symbolizes the task. A visual image of the nose on the
face may serve as a symbol of the part-whole relationship, a small
circle inside a larger one may symbolize the relation of an object to
a class of objects, and gesturing first to the right and then to the
left may symbolize the relationship of opposites. But as the subject
grows accustomed to a given task, these conscious symbols fade away,
and nothing remains except a general "feeling of readiness" or of
"knowing what you are {384} about". The mental set remains in force,
however, and is no less efficient for becoming almost unconscious.


Examples of Controlled Association

Dwelling so long on the test for controlled association may have
created the impression that this is a rather artificial and unusual
type of mental performance; but in reality controlled association is a
very representative mental process, and enters very largely into all
forms of mental work. This is true in arithmetical work, for example.
A pair of numbers, such as 8 and 3, has been linked in past experience
with several responses; it means 83, it means 11, it means 5, and it
means 24. But if you are adding, it means 11, and no other response
occurs; if you are multiplying, it means 24, and only that response
occurs. The mental set for multiplying facilitates the responses of
the multiplication table and inhibits those of the addition table,
while the mental set for adding does the reverse. Rapid adding or
multiplying would be impossible without an efficient mental set. Thus
in arithmetic, as in the tests, the mental set is an inner response to
the _task_.

In reading, there is a mental set which is an inner response to the
_context_, and which determines which of the several well-known
meanings of a word shall actually be called to mind when the word is
read. Presented alone, a word may call up any of its meanings,
according to frequency, etc.; but in context it usually brings to mind
just the one meaning that fits the context. The same is true of
conversation.

The objective _situation_ arouses a mental set that controls both
thought and action. The situation of being in church, for example,
determines the meanings that are got from the words heard, and
controls the motor behavior to {385} fit the occasion. The subject,
observing the situation, adjusts himself to it, perhaps without any
conscious effort, and his adjustment facilitates appropriate mental
and motor reactions, while inhibiting others.

A _problem_ arouses a mental set directed towards solution of the
problem. A difficult problem, however, differs from a context or
familiar task or situation in this important respect, that the
appropriate response has not been previously linked with the present
stimulus, so that, in spite of ever so good a mental set, the right
response cannot immediately be recalled. One must _search_ for the
right response. Still, the mental set is useful here, in directing the
search, and keeping it from degenerating into an aimless running
hither and thither. Problem solution is so different a process from
smooth-running controlled association that it deserves separate
treatment, which will be given it a few chapters further on, under the
caption of reasoning.

{386}

EXERCISES

1. Outline the chapter.

2. The rating of images belonging under different senses. Try to
   call up the images prescribed below, and rate each image according
   to the following scale:

  _3. . . . The image is practically the same as a sensation, as bright,
            full, incisive, and, in short, possessed of genuine
            sensory quality_.

  _2. . . . The image has a moderate degree of sensory quality_.

  _1. . . . The image has only faint traces of sensory quality_.

  _0. . . . No sensory image is called up, though there was a
            recall of the fact mentioned_.

  Call up visual images of: a friend's face, a sun flower, a white
  house among trees, your own signature written in ink.

  Call up auditory images of: the sound of your friend's voice, a
  familiar song, an automobile horn, the mewing of a cat.

  Call up olfactory images of: the odor of coffee, of new-mown hay, of
  tar, of cheese.

  Call up gustatory images of: sugar, salt, bitter, acid.

  Call up cutaneous images of: the feel of velvet, a lump of ice, a
  pencil held against the tip of your nose, a pin pricking your
  finger.

  Call up kinesthetic imagery of: lifting a heavy weight, reaching up
  to a high shelf, opening your mouth wide, kicking a ball.

  Call up organic imagery of: feeling hungry, feeling thirsty, feeling
  nausea, feeling buoyant.

  In case of which sense do you get the most lifelike imagery, and in
  case of which sense the least. By finding the average rating given
  to the images of each sense, you can arrange the senses in order,
  from the one in which your imagery rates highest to the one in which
  it rates lowest. It may be best to try more cases before reaching a
  final decision on this matter.

3. Verbal imagery. When you think of a word, do you have a visual,
   auditory, or kinesthetic image of it--or how does it come?

4. In reading, notice how much imagery of objects, persons, scenes,
   sounds, etc., occurs spontaneously.

5. Analysis of a revery. Take any object as your starting point,
   and let your mind wander from that wherever it will for a minute.
   {387} Then review and record the series of thoughts, and try to
   discover the linkages between them.

6. Free association experiment. Respond to each one of a list of
   disconnected words by saying the first word suggested by it. Use
   the following list: city, war, bird, potato, day, ocean, insect,
   mountain, tree, roof.

7. Controlled association, (a) Use the same list of stimulus words
   as above, but respond to each by a word meaning the _opposite_ or
   at least something contrasting, (b) Repeat, naming a _part_ of the
   object designated by each of these same words, (c) Repeat again,
   naming an _instance_ or variety of each of the objects named. Did
   you find wrong responses coming up, or did the mental set exclude
   them altogether?

8. Write on a sheet of paper ten pairs of one-place numbers, each
   pair in a little column with a line drawn below, as in addition or
   multiplication examples. See how long it takes you to _add_, and
   again how long it takes to _multiply_ all ten. Which task took the
   longer, and why? Did you notice any interference, such as thinking
   of a sum when you were "set" for products?

9. Free association test for students of psychology. Respond to
   each of the following stimulus words by the first word suggested by
   it of a psychological character:

   conditioned
   objective
   gregarious
   delayed
   correlation
   fear
   negative
   end-brush
   mastery
   rat
   pyramidal
   submission
   stimulus
   semicircular
   feeling-tone
   substitute
   kinesthetic
   primary
   axon
   advantage
   tension
   synapse
   field
   blend
   autonomic
   quotient
   rod
   retention
   limit
   fovea
   nonsense
   apraxia
   saturated
   higher
   thalamus
   red-green
   paired
   organic
   complementary
   economy
   tendency
   after
   exploration
   preparatory
   basilar
   recency
   native
   fluctuation
   curve
   endocrine
   dot
   perseveration
   expressive
   Binet
   synesthesia
   James-Lange
   frontal
   facilitation
   flexion
   overlapping

{388}

REFERENCES

On imagery, synesthesia, etc., see Gallon's _Inquiries into Human
Faculty and Its Development_, 1883, pp. 57-112; and for more recent
studies of imagery see G. H. Betts on _The Distribution and Function
of Mental Imagery_, 1909, and Mabel R. Fernald on _The Diagnosis of
Mental Imagery_, 1912.

On the diagnostic use of the association test, an extensive work is
that of C. G. Jung, _Studies in Word-Association_, translated by Eder,
1919.


{389}


CHAPTER XVI

THE LAWS OF ASSOCIATION

AN ATTEMPT TO REDUCE THE LEARNING PROCESS TO ITS ELEMENTS


This is a very serious occasion. What we now have before us is one of
the great outstanding problems of psychology, a problem that has come
down through the ages, with succeeding generations of psychological
thinkers contributing of their best to its solution; and our task is
to attack this problem afresh in the light of modern knowledge of the
facts of learning and memory. We wish to gather up the threads from
the three preceding chapters, which have detailed many facts regarding
learned reactions of all sorts, and see whether we cannot summarize
our accumulated knowledge in the form of a few great laws. We wish
also to relate our laws to what is known of the brain machinery.


The Law of Exercise

Of one law of learning, we are perfectly sure. There is no doubt that
the exercise of a reaction strengthens it, makes it more precise and
more smooth-running, and gives it an advantage over alternative
reactions which have not been exercised. Evidence for these statements
began to appear as soon as we turned the corner into this part of our
subject, and has accumulated ever since. This law is sometimes called
the "law of habit", but might better be called the "law of improvement
of a reaction through exercise", or, more briefly, the "law of
exercise".

{390}

The law of exercise is very broad in its scope, holding good of life
generally and not alone of mental life. Exercise of a muscle develops
the muscle, exercise of a gland develops the gland; and, in the same
way, exercise of a mental reaction strengthens the machinery used in
making that reaction.

Let us restate the law in terms of stimulus and response. _When a
given stimulus arouses a certain response, the linkage between that
stimulus and that response is improved by the exercise so obtained_,
and thereafter the stimulus arouses the response more surely, more
promptly, more strongly than before.

Under the law of exercise belong several _sub-laws_ already familiar
to us.

1. The law of _frequency_ refers to the cumulative effect of repeated
exercise. The practice curve gives a picture of this sub-law, showing
how improvement with repeated exercise of a performance is rapid at
first and tapers off into the physiological limit, beyond which level
more repetition cannot further improve the performance. The
superiority of "spaced study" over unspaced means that exercise is
more effective when rest periods intervene between the periods of
exercise; as this is notoriously true of muscular exercise, it is not
surprising to find it true of mental performances as well.

2. The law of _recency_ refers to the gradual weakening of the
machinery for executing a reaction when no longer exercised; it is the
general biological law of "atrophy through disuse" applied to the
special case of learned reactions. As exercise improves the linkage
between stimulus and response, so disuse allows the linkage to
deteriorate. This law is pictured more completely and quantitatively
in the curve of forgetting.

Really, there are two laws of recency, the one being a {391} law of
retention, the other a law of momentary warming up through exercise.
The law of retention, or of forgetting, is the same as atrophy through
disuse. The warming-up effect, well seen in the muscle which is
sluggish after a long rest but becomes lively and responsive after a
bit of exercise, [Footnote: See p. 73.] appears also in the fact that
a skilled act needs to be done a few times in quick succession before
it reaches its highest efficiency, and in the fact of "primary
memory", the lingering of a sensation or thought for a few moments
after the stimulus that aroused it has ceased. Primary memory is not
strictly memory, since it does not involve the recall of facts that
have dropped out of mind, but just a new emphasis on facts that have
not yet completely dropped out. Warming up is not a phenomenon of
learning, but it is a form of recency, and is responsible for the very
strong "recency value" that is sometimes a help in learning,
[Footnote: See p. 345.] and sometimes a hindrance in recall.
[Footnote: See p. 356.]

3. The law of _intensity_ simply means that vigorous exercise
strengthens a reaction more than weak exercise. This is to be
expected, but the question is, in the case of mental performances, how
to secure vigorous exercise. Well, by active recitation as compared
with passive reception, by close attention, by high level observation.
In active recitation, the memorizer strongly exercises the performance
that he is trying to master, while in reading the lesson over and over
he is giving less intense exercise to the same performance.


The Law of Effect

We come now to a law which has not so accepted a standing as the law
of exercise, and which may perhaps be another sub-law under that
general law. The "law of effect" may, however, be regarded simply as a
generalized statement of {392} the facts of learning by trial and
error. The cat, in learning the trick of escaping from a cage by
turning the door-button, makes and therefore exercises a variety of
reactions; and you might expect, then, in accordance with the law of
exercise, that all of these reactions would be more and more firmly
linked to the cage-situation, instead of the successful reaction
gradually getting the advantage and the unsuccessful being eliminated.
The law of effect, stated as objectively as possible, is simply that
the successful or unsuccessful outcome or _effect_ of a reaction
determines whether it shall become firmly linked with the stimulus, or
detached from the stimulus and thus eliminated. _The linkage of a
response to a stimulus is strengthened when the response is a success,
and weakened when the response is a failure_.

Success here means reaching the goal of an awakened desire or
_reaction-tendency_, and failure means being stopped or hindered from
reaching the goal. Since success is satisfying and failure unpleasant,
the law of effect is often stated in another form: a response that
brings satisfaction is more and more firmly attached to the situation
and reaction-tendency, while a response that brings pain or
dissatisfaction is detached.

The law of effect is a statement of fact, but the question is whether
it is an ultimate fact, or whether it can be explained as a special
case of the law of exercise. Some have suggested that it is but a
special case of the sub-law of frequency; they call attention to the
fact that the successful response must be made at every trial, since
the trial continues till success is attained, whereas no one
unsuccessful response need be made at every trial; therefore in the
long run the successful response must gain the frequency advantage.
But there is a very ready and serious objection to this argument; for
it may and does happen that an unsuccessful response is repeated
several times during a single {393} trial, while the successful
response is never made more than once in a single trial, since success
brings the trial to a close; and thus, as a matter of fact, frequency
often favors the unsuccessful response--which, nevertheless, loses out
in competition with the successful response.

Can the law of effect be interpreted as an instance of the sub-law of
recency? The successful reaction always occurs at the end of a trial,
and is the most recent reaction at the beginning of the next trial.
This recency might have considerable importance if the next trial
began instantly (as in unspaced learning), but can have no importance
when so long as interval as a day is left between trials; for
evidently the recency of twenty-four hours plus ten seconds is not
effectively different from that of an even twenty-four hours. Recency,
then, does not explain the law of effect.

Can it be explained as an instance of the sub-law of intensity? An
animal, or man, who sees success coming as he is making the reaction
that leads directly to success, throws himself unreservedly into this
reaction, in contrast with his somewhat hesitant and exploratory
behavior up to that time. The dammed-up energy of the
reaction-tendency finds a complete outlet into the successful
reaction, and therefore the successful reaction is more intensely
exercised than the unsuccessful. This seems like a pretty good
explanation, though perhaps not a complete explanation.


Limitations of the Law of Exercise

The law of exercise, with all its sub-laws, is certainly fundamental
and universal; it is always in operation whenever anything is learned;
and yet, just by itself, it goes only halfway towards accounting for
learned reactions. For a reaction to be exercised, it must be _made_,
and the law of exercise presupposes that it is made, and does not
attempt to account for its being made in the first place.

{394}

The law of exercise does not cover the formation of new linkages, but
only the strengthening of linkages that are already working. It does
not explain the attachment of a response to some other than its
natural stimulus, nor the combination, of responses into a higher
unit, nor the association of two facts so that one later recalls the
other. We learn by doing, but how can we do anything new so as to
start to learn? We learn by observing combinations of facts, but how
in the first place do we combine the facts in our minds?

How, for example, can we learn to respond to the sight of the person
by saying his name? Evidently, by exercising this linkage of stimulus
and response. But how did we ever make a start in responding thus,
since there is nothing about the person's looks to suggest his name?
The name came to us through the ear, and the face by way of the eye;
and if we repeated the name, that was a response to the auditory
stimulus and not to the visual. How has it come about, then, that we
later respond to the visual stimulus by saying the name?

In short, the more seriously we take the law of exercise, the more we
feel the need of a supplementary law to provide for the first making
of a reaction that then, by virtue of exercise, is strengthened.

This is the problem that occupied the older writers on psychology when
they dealt with "association"; and their solution of the problem was
formulated in the famous "laws of association". The laws of
association were attempts to explain how facts got associated, so that
later one could recall another.

These laws have a long history. From Aristotle, the ancient Greek who
first wrote books on psychology, there came down to modern times four
laws of association. Facts become associated, according to Aristotle,
when they are {395} contiguous (or close together) in space, or when
they are contiguous in time, or when they resemble each other, or when
they contrast with each other. The psychologists of the earlier modern
period, in the eighteenth and first part of the nineteenth centuries,
labored with very good success to reduce these four laws to one
comprehensive law of association. Contiguity in space and in time were
combined into a law of association by _contiguity in experience_,
since evidently mere physical contiguity between two objects could
establish no association between them in any one's mind except as he
experienced them together.


Association by Similarity

Continuing their simplification of the laws of association, these
older psychologists showed that resemblance and contrast belonged
together, since to be similar things must have something in common,
and to be contrasted also two things must have something in common.
You contrast north with south, a circle and a square, an automobile
and a wheelbarrow; but no one thinks of contrasting north with a
circle, south with an automobile, or a square and a wheelbarrow,
though these pairs are more incongruous than the others. Things that
are actually associated as contrasting with each other have something
in common; and therefore association by contrast could be included
under association by similarity. Thus the four laws had been reduced
to two, association by contiguity and association by similarity.

The final step in this reduction was to show that association by
similarity was a special case of association by contiguity. To be
similar, two things must have something in common, and this common
part, being contiguous with the remainder of each of the two things,
establishes an indirect contiguity between the two things, a {396}
sort of contiguity bridge between them. One thing has the parts or
characteristics, A B X Y, and the similar thing has the parts or
characteristics, C D X Y; and thus X Y, when seen in the second thing,
call up A B, with which they are contiguous in the first thing.

A stranger reminds me of my friend because something in the stranger's
face or manner has been met with before in my friend; it has been
contiguous with my friend, and recalls him by virtue of this
contiguity. The stranger, as a whole individual, has never been
contiguous with my friend, but some characteristic of the stranger has
been thus contiguous. In association by similarity, it is not the
whole present object that arouses recall of the similar object, but
some _part_ of the present object. This kind of association is
important in thinking, since it brings together facts from different
past experiences, and thus assembles data that may be applied to a new
problem. If every new object or situation could only be taken as a
whole, it could not remind me of anything previously met; and I should
be like an inexperienced child in the presence of each new problem;
but, taken part by part, the novel situation has been met with before,
and can be handled in the light of past experience.

Exactly what there is in common between two similar faces or other
objects cannot always be clearly made out; but the common
characteristic is there, even if not consciously isolated, and acts as
an effective stimulus to recall.


Association by Contiguity

This reduction of all the laws of association to one great law was no
mean achievement; and the law of association by contiguity in
experience holds good. If one thing recalls another to your mind, you
can be sure that the two {397} have been contiguous in your
experience, either as wholes or piecemeal. For two things to become
associated, they must be experienced together.

Yes, the law holds good, when thus stated--but notice that the
statement is virtually negative. It says, in effect, that two things
do _not_ become associated _unless_ they are contiguous in experience.
If it were turned about to read that two things do become associated
if they are contiguous in experience, it would no longer be a true
law, for the exceptions would then be extremely numerous.

The memory and testimony experiments have brought many exceptions to
light. Show a person twenty pictures in a row, and let him examine
each one in turn so closely that he can later recognize every one of
them; and still he will not have the adjacent pictures so associated
that each one can call up the next in order. To accomplish his last
task, he has to observe the order specifically; it is not enough that
he simply experiences pictures together. Or, again, read to a person
twenty pairs of words, asking him to notice the pairs so that later he
can respond by the second word of any pair when the first word is
given him; and read the list through three or four times, so that he
shall be able to make almost a perfect score in the expected test;
still he will have formed few associations between the contiguous
pairs, and will make a very low score if you ask him to recite the
pairs in order. Many similar experiments have yielded the same general
result--contiguity in experience and still no association.

The law of association by contiguity is unsatisfactory from a modern
standpoint because it treats only of the stimulus, and says nothing
about the response. It states, quite truly, that stimuli must be
contiguous in order that an association between them may be formed,
but it neglects to state that the association, being something in us,
must {398} be formed by our reaction to the stimuli. It is especially
necessary to consider the response because, as we have just seen, the
response is not always made and the association, therefore, not always
formed. Only if the stimuli are contiguous, can the associating
response be aroused, but they do not infallibly arouse it even if they
are contiguous.

The law of contiguity is incomplete, also, because it is not
applicable to the association of two motor acts into a cooerdinated
higher unit, or of the combination of two primary emotions into a
higher emotional unit.

In a word, the time-honored law of association is no longer
satisfactory because it does not fit into a stimulus-response
psychology. It comes down from a time when the motor side of mental
performances was largely overlooked by psychology, and when the
individual was pictured as being passively "impressed" with the
combinations of facts that were presented to his senses.


The Law of Combination

What we need, then, as an improvement on the old law of association by
contiguity, and as a supplement to the law of exercise, is some law
governing the response to two or more contiguous stimuli. Now we
already have such a law, which we put to some use in studying
attention, [Footnote: See pp. 268-264.] and called the law of
"combination", or of "unitary response to a plurality of stimuli". We
had better fetch that law out again and put it in good repair, and see
whether it is adequate for the job that we now have on hand. In a very
general, abstract form, the law of combination read that "two or more
stimuli may arouse a single joint response". Let us add a single word,
which had not risen above the horizon when we formulated the law
before, and say that {399} _two or more contiguous stimuli may arouse
a single joint response_.

That seems very little to say; can we possibly go far with so simple a
statement? Well, let us see. In saying that two or more stimuli arouse
a single response, we imply that _there is already some rudimentary
linkage between each stimulus and their common response, and that this
linkage is used in arousing the response_. Now bring in our trusty law
of exercise, and we see that the use, or exercise, of such a linkage
may strengthen it to such an extent that, _later, a single one of the
stimuli may arouse the response which was originally aroused by the
whole collection of stimuli_.

Does that promise any better? Probably it requires further discussion
and exemplification before its value can be appreciated. Let us, then,
first discuss it a bit, and then apply it to the explanation of the
chief varieties of learned reaction that have come to our attention.

The law of combination attempts to show how it comes about that a
stimulus, originally unable to arouse a certain response, acquires the
power of arousing it; and the law states that this occurs only when
the originally ineffective stimulus is combined with others which can
and do arouse the response. The ineffective stimulus, being one of a
combination of stimuli which collectively arouse the response,
participates to some slight degree in arousing that response and may
thus become effectively linked with the response.

Notice an assumption underlying the law of combination. Evidently a
stimulus could not take part in arousing a response unless there were
some pre-existing linkage between it and the response. This linkage
may however be extremely loose and feeble, and wholly incapable by
itself of arousing the response. The assumption of pre-existing loose
linkage between almost any stimulus and almost any response is
justified by the facts of playful behavior and trial and error {400}
behavior. In addition to the close reflex connections provided in the
native constitution, and in addition also to the close connections
formed in previous training, there are at any time, and especially in
childhood and youth, a vast number of loose connections. These are too
weak to operate singly, until they have cooeperated in producing a
response, and thus been individually strengthened, after which they
may be able singly to produce the response.

The law of combination, then, as applied to learning, includes four points:

  (a) A collection of stimuli may work together and arouse a single
      response.

  (b) This is possible because of pre-existing loose linkage between
      the separate stimuli and the response.

  (c) When any stimulus, working together with others, helps to arouse
      a response, its linkage with that response is strengthened by
      exercise.

  (d) The linkage may be sufficiently strengthened so that a single
      stimulus can arouse the response without help from the other
      stimuli that were originally necessary.

Having now abundantly stated and reiterated the law of combination in
the abstract, let us turn to concrete instances of learned reactions,
and see how the law takes care of them. We have already classified a
large share of all the concrete instances under a few main heads, as
substitute stimulus, substitute response, combination (or association)
of stimuli, and combination of responses. We shall presently find it
possible to reduce these four classes to two, since the association of
two objects, by virtue of which one of them later recalls the other,
is a rather complicated case of substitute stimulus, while the
combination of movements into a higher unit is a complicated case of
substitute response.

  [Footnote: To distinguish between "substitute stimulus" and
  "substitute response" is, in strict logic, like distinguishing
  between "inside out" and "outside in." Whenever there is a
  substitute stimulus there is also a substitute response, of course,
  since this stimulus, in being substituted for another, gets that
  other's response in place of its own original response; and in the
  same way, you can always find substitute stimulus in any instance of
  substitute response; for, in being substituted for another, a
  response gets that other's stimulus in place of its own original
  stimulus. For all that, the distinction between the two main cases
  of learning is of some importance, since sometimes the changed
  stimulus, and sometimes the changed response, is the interesting
  fact.]

{401}

I. SUBSTITUTE STIMULUS EXPLAINED BY THE LAW OF COMBINATION

Here the response, without being itself essentially changed, becomes
attached to a new stimulus. We distinguish two cases under the general
head of substitute stimulus. In the one case, the substitute stimulus
was originally extraneous, and unnecessary for arousing the response,
while in the other case it was originally necessary as part of a team
of stimuli that aroused the response.


A. Substitute Stimulus Originally Unnecessary for Arousing the
Response

1. Conditioned reflex.

This is the very simplest case belonging under the law of combination.
The dog that responded to the bell by a flow of saliva, after the bell
plus a tasting substance had acted together on him time after time, is
the typical instance; and another good instance is that of the little
child who was "taught" to shrink from a rabbit by the sounding of a
harsh noise along with the showing of the rabbit. [Footnote: See p.
303.] The explanation of all instances of conditioned reflex is the
same. We have an effective stimulus acting, i.e., a stimulus strongly
linked with the response; and we also have acting an ineffective
stimulus, which gets drawn into the same reaction. The effective
stimulus determines what response shall be made, and the other
stimulus finds an outlet {402} into that response, being, as it seems,
attracted towards the activated response, sucked into it. The weak
linkage from the ineffective stimulus to the response, being thus used
and strengthened, later enables this stimulus to arouse the response
single-handed.

This sort of thing is best presented in a diagram. A full line in the
diagram denotes a linkage strong enough to work alone, while a dotted
line denotes a weak linkage. Letters stand for stimuli and responses.
In the diagram for conditioned reflex, A is the original effective
stimulus (the rasping noise in the instance of the child and the
rabbit), and B is the ineffective stimulus (the sight of the rabbit).
R is the shrinking response, linked strongly to the stimulus A and
only weakly to the stimulus B, which has several other linkages fully
as good as the linkage B-R. But A arouses the response R; and R, being
thus activated, draws on B and brings the linkage B-R into use. After
this has occurred a number of times, the linkage B-R has been so
strengthened by repeated exercise that it can operate alone, so that
the rabbit brings the shrinking response even in the absence of A, the
noise.


[Illustration: Fig. 55.--Attachment of the substitute stimulus in the
case of the conditioned reflex.]


At first, the child shrinks from the noise, but, the rabbit being
before his eyes, he incidentally shrinks from the rabbit as well. He
really shrinks in response to all the stimuli acting on him at that
moment. He shrinks from the whole situation. He makes a unitary
response to the whole collection of contiguous stimuli, and thus
exercises the linkage between each stimulus and their joint response.
The {403} linkage between rabbit and shrinking is later strong enough
to work alone. It is a clear case of the law of combination.


2. Learning the names of things.

A child who can imitate simple words that he hears is shown a penny
and the word "penny" is spoken to him. To this combination of stimuli
he responds by saying the word. This is primarily a response to the
auditory stimulus, since the sight of the penny, though it might
probably have aroused some response, and even some vocal response from
the child, had no strong linkage with this particular vocal response.
But the auditory stimulus determined the response, and attracted the
visual stimulus into this particular channel of saying "penny". The
linkage from the sight of the penny to the saying of this word being
thus strengthened by exercise, the seen penny later gives the right
vocal response, without any auditory stimulus to assist.


  [Illustration: Fig. 56.--Linkage of a name to an object. The diagram
  is arranged to illustrate the formation of a linkage from the sight
  of the object to saying its name. A very similar diagram would
  illustrate the linkage from the name to the thought or image of the
  object. The acquiring of mental images seems to be essentially the
  same process as the acquiring of conditioned reflexes, and of names.
  (Figure text: object seen, various possible responses, name heard,
  name spoken)]


{404}

B. Substitute Stimulus Originally an Essential Member Of A Team of
Stimuli That Aroused the Response

1. Observed grouping or relationship.

"Learning by observation" is a very important human accomplishment,
and we found many evidences of its importance in our study of the
process of memorizing. The facts observed, which assist memory so
greatly, are usually relations or groups.


[Illustration: Fig. 57.--The formation of an association between two
objects by observing their grouping or relationship. (Figure text:
response of observing the Group A B, thought of Group A B)]


Evidently the observation of a group of things is a response to a
collection of stimuli, and could not originally be aroused by any one
of the stimuli alone. The same is true of observing a relationship;
the observation is a response to two things taken together, and not,
originally, to either of the two things taken alone. In spite of this,
a single one of the things may later call to mind the relationship, or
the group; that is, it arouses the response originally made to the
pair or group of stimuli. The single stimulus has been substituted for
the team that originally aroused the response. Its linkage with the
response has been so strengthened by exercise as to operate
effectively without assistance.

For example, in learning pairs of words in a "paired {405} associates
experiment", [Footnote: See p. 336.] the subject is apt to find some
relation between the words forming a pair, even though they are
supposed to be "unrelated words". When he has thus learned the pair,
either of the words in it will recall the observed relation and the
other word of the pair. Sometimes, after a long interval especially,
the relation is recalled without the other word. One subject fixed the
pair, "windy--occupy", by thinking of a sailor occupying a windy perch
up in the ropes. Some weeks later, on being given the word "windy", he
recalled the sailor on the perch, but could not get the word "occupy".
That is, he made the same response to "windy" that he had originally
made to "windy--occupy", but did not get the response completely
enough to give the second word.

In the typical cases of _association by contiguity_ when one object
reminds us of another that was formerly experienced together with it,
the law of combination comes in as just described. The two objects
were observed to be grouped or related in some way, or some such
unitary response was made to the two objects taken together, and this
response became so linked to each of the objects that later a single
one of them arouses this unitary response and recalls the other
object. In the free association test, [Footnote: See p. 380.] the
stimulus word "dimple" calls up the previously made response of seeing
a dimple in a cheek, and so leads to the word "cheek". In a controlled
association test, where opposites are required, the stimulus word
"mythical" arouses the previously made observation of the antithesis
of mythical and historical, and so leads to the motor response of
saying the latter word.

  [Footnote: When, however, this indirect linkage between stimulus and
  motor response is frequently exercised, short-circuiting takes place
  (see p. 338), and the stimulus word arouses the motor response
  directly. Short-circuiting follows the law of combination very
  nicely. Let a stimulus S arouse an idea I and this in turn a motor
  act M. S--I--M represents the linkages used. But undoubtedly there
  is a weak pre-existing linkage directly across from S to M, and this
  gets used to a slight degree, strictly according to the conditioned
  reflex diagram, with I playing the part of the effective stimulus in
  arousing M, and S the part of the originally ineffective stimulus.
  By dint of being exercised in this way, the linkage S--M becomes
  strong enough to arouse the motor response directly, and I is then
  very likely to be left out altogether.]


{406}

2. Response by analogy and association by similarity.

When an object reminds me of a similar object, that is association by
similarity. But suppose I actually take the object to be the similar
object, and behave towards it accordingly; then my reaction is called
"response by analogy". Once, when far from home, I saw a man whom I
took to be an acquaintance from my home town, and stepped up to him,
extending my hand. He did not appear very enthusiastic, and informed
me that, in his opinion, I had made a mistake. This was response by
analogy, but if I had simply said to myself that that man looked like
my acquaintance, that would have been association by similarity.
Really, association by similarity is the more complex response, for it
involves response to the points of newness in the present object, as
well as to the points of resemblance to the familiar object, whereas
response by analogy consists simply in responding to the points of
resemblance.

Response by analogy often appears in little children, as when they
call all men "papa"' or as when they call the squirrel a "kitty" when
first seen. If they call it a "funny kitty", that is practically
association by similarity, since the word "funny" is a response to the
points in which a squirrel is different from a cat, while the word
"kitty" is a response to the points of resemblance.

But response by analogy is not always so childish or comic as the
above examples might seem to imply. When we respond to a picture by
recognizing the objects depicted, that is response by analogy, since
the pictured object is only {407} partially like the real object; a
bare outline drawing may be enough to arouse the response of "seeing"
the object. Other instances of response by analogy will come to light
when, in the next chapter, we come to the study of perception.


[Illustration:  Fig. 58.--Response by analogy. The letters, A, B, X,
Y, represent the several stimuli that make up the original object, and
each of them becomes well linked with their common response (seeing
the object, and perhaps naming it). When the linkage between X and Y
and the response has become strong, a similar object, presenting X and
Y along with other new stimuli, C and D, appears, and arouses the old
response, by virtue of the now-effective linkage from X and Y to this
response.]


[Illustration: Fig. 59.--Association by similarity. Everything here as
in the previous diagram, except that C and D get a response in
addition to that aroused by X and Y, and so the new object is seen to
be new, while at the same time it recalls the old object to mind.]


The machinery of response by analogy is easily understood by aid of
the law of combination. A complex object, presenting a number of parts
and characteristics, arouses the response of seeing and perhaps naming
the object. This is a unitary response to a collection of stimuli, and
each of the parts or characteristics of the object participates in
arousing the response, and the linkage of each part with the response
is thus strengthened. Later, therefore, the whole identical object is
not required to arouse this same {408} response, but some of its parts
or characteristics will give the response, and they may do this even
when they are present in an object that has other and unfamiliar parts
and characteristics.

The machinery of association by similarity is the same, with the
addition of a second response, called out by the new characteristics
of the present object.


II. SUBSTITUTE RESPONSE EXPLAINED BY THE LAW OF COMBINATION

The substitute response machinery is more complicated than that of the
substitute stimulus, as it includes the latter and something more.
What that something more is will be clear if we ask ourselves why a
substitute response should ever be made. Evidently because there is
something wrong with the original response; if that were entirely
satisfactory, it would continue to be made, and there would be no room
for a substitute. The original response being unsatisfactory to the
individual, how is he to find a substitute? Only by finding some
stimulus that will arouse it. This is where trial and error come in,
consisting in a search for some extra stimulus that shall give a
satisfactory response.

Suppose now that the extra stimulus has been found which arouses a
satisfactory substitute response. The original stimulus, or the
reaction-tendency aroused by it, still continuing, participates in
arousing the substitute response, playing the part of the originally
ineffective stimulus in the conditioned reflex. Thus the original
stimulus becomes strongly linked with the substitute response.

The process of reaching a substitute response thus includes three
stages: (a) original response found unsatisfactory, (b) new stimulus
found which gives a satisfactory substitute response, (c) attachment
of the substitute response to the original stimulus.

{409}

There are two main cases under the general head of substitute
response. In one case, the substitute response is essentially an old
response, not acquired during the process of substitution, but simply
substituted, as indicated just above, for the original response to the
situation. This represents the common trial and error learning of
animals. The second case is that where the substitute response has to
be built up by combination of old responses into a higher unit.


C. Substitute Response, but not in Itself a New Response

I. Trial and error.

Our much-discussed instance of the _cat in the cage_ need not be
described again, but may simply be illustrated by a diagram.


[Illustration: Fig. 60.--How the cat learns the trick of escaping from
the cage by unlatching the door. S is the situation of being shut up
in a cage, and T is the tendency to get out. R1 is the primary
response aroused by this tendency, which response meets with failure,
not leading to the end-result of the tendency. Responses are then made
to various particular stimuli about the cage, and one of these
stimuli, the door-latch, X, gives the response R2 which leads to the
end-result. Now the response R2 was in part aroused by T, and its
pre-existing weak linkage with T is so strengthened by exercise that
T, or we may say S, comes to give the correct response without
hesitation.]

{410}

2. Learning to balance on a bicycle.

When the beginner feels the bicycle tipping to the left, he naturally
responds by leaning to the right, and even by turning the wheel to the
right. Result unsatisfactory--strained position and further tipping to
the left. As the bicyclist is about to fall, he saves himself by a
response which he has previously learned in balancing on his feet; he
extends his foot to the left, which amounts to a response to the
ground on the left as a good base of support. Now let him sometime
respond to the ground on his left by turning his wheel that way, and,
to his surprise and gratification, he finds the tipping overcome, and
his balance well maintained. The response of turning to the left,
originally made to the ground on the left (but in part to the
tipping), becomes so linked with the tipping as to be the prompt
reaction whenever tipping is felt. The diagram of this process would
be the same as for the preceding instance.


D. Substitute Response, the Response Being a Higher Motor Unit

1. The brake and clutch combination in driving an automobile.

This may serve as an instance of _simultaneous cooerdination_, since
the two movements which are combined into a higher unit are executed
simultaneously. The beginner in driving an automobile often has
considerable trouble in learning to release the "clutch", which,
operated by the left foot, ungears the car from the engine, and so
permits the car to be stopped without stopping the engine. The foot
brake, operated by the right foot, is comparatively easy to master,
because the necessity for stopping the car is a perfectly clear and
definite stimulus. Now, when the beginner gets a brake-stimulus, he
responds promptly with his right foot, but neglects to employ his left
foot on the clutch, because he has no effective clutch-stimulus; there
is nothing {411} in the situation that reminds him of the clutch.
Result, engine stalled, ridicule for the driver. Next time, perhaps,
he _thinks_ "clutch" when he gets the brake-stimulus, and this
thought, being itself a clutch-stimulus, arouses the clutch-response
simultaneously with the brake-response. After doing this a number of
times, the driver no longer needs the thought of the clutch as a
stimulus, for the left foot movement on the clutch has become
effectively linked with the brake-stimulus, so that any occasion that
arouses the brake-response simultaneously arouses the clutch response.


[Illustration: Fig. 61.--Combining clutch-response with
brake-response. At first, the brake-stimulus has only a weak linkage
with the clutch-response, and an extra stimulus has to be found to
secure the clutch-response. But whenever the clutch-response is made
while the brake-stimulus is acting, the weak linkage between these two
is exercised, till finally the brake-stimulus is sufficient to give
the clutch-response, along with the brake-response.]


The combination of two responses is effected by linking both to the
same stimulus; thus the two become united into a cooerdinated higher
motor unit.


2. The word-habit in typewriting furnishes an example of _successive
cooerdination_, the uniting of a sequence of movements into a higher
unit. [Footnote: See p. 324.] The beginner has to spell out {412} the
word he is writing, and make a separate response to each letter; but
when he has well mastered the letter-habits, and, still unsatisfied,
is trying for more speed, it happens that he thinks ahead while
writing the first letter of a word, and _prepares_ for the second
letter. In effect, he commences reacting to the second letter while
still writing the first. This goes further, till he anticipates the
series of letters forming a short word while still at the beginning of
the word. The letter movements are thus linked to the thought of the
word as a whole, and the word becomes an effective stimulus for
arousing the series of letter movements.


[Illustration: Fig. 62.--Learning a word-habit in typewriting. At
first, besides the stimulus of the word, "_and_" it is necessary also
to have the stimulus "_a_" in order to arouse the response of writing
a, the stimulus "_n_" in order to arouse the writing of n, and the
stimulus "_d_" in order to arouse the writing of d. Yet the stimulus
"_and_" is present all this time, and its weak linkages with the
writing movements are used and strengthened, so that finally it is
sufficient, by itself, to arouse the whole series of writing
movements.]


Many other instances of learning can be worked out in the same way,
and there seems to be no difficulty in {413} interpreting any of them
by the law of combination. Even "negative adaptation" can possibly be
interpreted as an instance of substitute response; some slight and
easy response may be substituted for the avoiding reaction or the
attentive reaction that an unimportant stimulus at first arouses,
these reactions being rather a nuisance when they are unnecessary. On
the whole, the law of combination seems to fill the bill very well. It
explains what the law of exercise left unexplained. It always brings
in the law of exercise as an ally, and, in explaining substitute
response, it brings in the law of effect, which however, as we saw
before, may be a sub-law under the law of exercise. These two, or
three laws, taken together, give an adequate analysis of the whole
process of learning.


The Law of Combination in Recall

Unitary response to multiple stimuli is important in recall as well as
in learning. The clearest case of this is afforded by "controlled
association". [Footnote: See p. 381.]

In an opposites test, the response to the stimulus word "long" is
aroused partly by this stimulus word, and partly by the "mental set"
for opposites. There are two lines of influence, converging upon the
response, "long--short" (of which only the word "short" may be
spoken): one line from the stimulus word "long", and the other from
the mental set for pairs of opposite words. The mental set for
opposites tends to arouse any pair of opposites; the word "long" tends
to arouse any previously observed group of words of which "long" is a
part. The mental set, an internal stimulus, and the stimulus word
coming from outside, converge or combine to arouse one particular
response.

The mental set for adding has previously exercised {414} linkages with
the responses composing the addition table, while the mental set for
multiplication has linkages with the responses composing the
multiplication table. When the set for adding is active, a pair of
numbers, seen or heard, together with this internal stimulus of the
mental set, arouses the response that gives the sum; but when the
multiplying set is active, the same pair of numbers gives the product
as the response. All thinking towards any goal is a similar instance
of the law of combination.


The Laws of Learning in Terms of the Neurone

We have good evidence that the brain is concerned in learning and
retention. Loss of some of the cortex through injury often brings loss
of learned reactions, and the kind of reactions lost differs with the
part of the cortex affected. Injury in the occipital lobe brings loss
of visual knowledge, and injury in the neighborhood of the auditory
sense-center brings loss of auditory knowledge.

Injury to the retina or optic nerve, occurring early in life, results
in an under-development of the cortex in the occipital lobe. The nerve
cells remain small and their dendrites few and meager, because they
have not received their normal amount of exercise through stimulation
from the eye.

Exercise, then, has the same general effect on neurones that it has on
muscles; it causes them to grow and it probably also improves their
internal condition so that they act more readily and more strongly.
The growth, in the cortex, of dendrites and of the end-brushes of
axons that interlace with the dendrites, must improve the synapses
between one neurone and another, and thus make better conduction paths
between one part of the cortex and another, and also between the
cortex and the lower sensory and motor centers.

The law of exercise has thus a very definite meaning when {415}
translated into neural terms. It means that the synapses between
stimulus and response are so improved, when traversed by nerve
currents in the making of a reaction, that nerve currents can get
across them more easily the next time.


[Illustration: Fig. 63.--The law of exercise in terms of synapse. A
nerve current is supposed to pass along this pair of neurones in the
direction of the arrow. Every time it passes, it exercises the
end-brush and dendrites at the synapse (for the "passage of a nerve
current" really means activity on the part of the neurones through
which it passes), and the after-effect of this exercise is growth of
the exercised parts, and consequent improvement of the synapse as a
linkage between one neurone and the other. Repeated exercise may
probably bring a synapse from a very loose condition to a state of
close interweaving and excellent power of transmitting the nerve
current.]


The more a synapse is used, the better synapse it becomes, and the
better linkage it provides between some stimulus and some response.
The cortex is the place where linkages are made in the process of
learning, and it is there also that forgetting, or atrophy, takes
place through disuse. Exercise makes a synapse closer, disuse lets it
relapse into a loose and poorly conducting state.

The law of combination, also, is readily translated into {416} neural
terms. The "pre-existing loose linkages" which it assumed to exist
undoubtedly do exist in the form of "association fibers" extending in
vast numbers from any one part of the cortex to many other parts.
These fibers are provided by native constitution, but probably
terminate rather loosely in the cortex until exercise has developed
them. They may be compared to telephone wires laid down in the cables
through the streets and extending into the houses, but still requiring
a little fine work to attach them properly to the telephone
instruments.


[Illustration: Fig. 64.--Diagram for the learning of the name of an
object, transformed into a neural diagram. The vocal movement of
saying the name is made in response to the auditory stimulus of
hearing the name, but when the neurone in the "speech center" is thus
made active, it takes up current also from the axon that reaches it
from the visual center, even though the synapse between this axon and
the speech neurone is far from close. This particular synapse between
the visual and the speech centers, being thus exercised, is left in an
improved condition. Each neurone in the diagram represents hundreds in
the brain, for brain activities are carried on by companies and
regiments of neurones. (Figure text: object seen, visual center name
heard, auditory center, speech center, name spoken)]


The diagrams illustrating different cases under the law of combination
can easily be perfected into neural diagrams, though, to be sure, any
diagram is ultra-simple as compared with the great number of neurones
that take part in even a simple reaction.

The reader will be curious to know now much of this neural
interpretation of our psychological laws is observed fact, and how
much speculation. Well, we cannot as yet {417} observe the brain
mechanism in actual operation--not in any detail. We have good
evidence, as already outlined, for growth of the neurones and their
branches through exercise.


[Illustration: Fig. 65.--Control, in multiplying. The visual stimulus
of two numbers in a little column, has preformed linkages both with
the adding response and with that of multiplying. But the mental set
for adding being inactive at the moment, and that for multiplying
active (because the subject means to multiply), the multiplying
response is facilitated.]


We have perfectly good evidence of the law of "unitary response to
multiple stimuli" from the physiological study of reflex action; and
we have perfectly good anatomical evidence of the convergence and
divergence of neural paths of connection, as required by the law of
combination. The association fibers extending from one part to another
of the cortex are an anatomical fact. [Footnote: See p. 56.]
Facilitation is a fact, and that means that a stimulus which could not
of itself arouse a response can cooeperate with another stimulus that
has a direct connection with that response, and reinforce its effect.
In short, all the elements required for a neural law of combination
are known facts, and the only matter of doubt is whether we have built
these elements together aright in our interpretation. It is not pure
speculation, by any means.

{418}


EXERCISES

1. Outline the chapter, in the form of a list of laws and sub-laws.

2. Review the instances of learning cited in Chapters XIII-XV,
   and examine whether they are covered and sufficiently accounted for
   by the general laws given in the present chapter.

3. Draw diagrams, like those given in this chapter, for the simpler
   cases, at least, that you have considered in question 2.

4. Show that response by analogy is important in the development
   of language. Consider metaphor, for example, and slang, and the
   using of an old word in a new sense (as in the case of
   'rail-road').


REFERENCES

William James devoted much thought to the problem of the mechanism of
learning, habit, association, etc., and his conclusions are set forth
in several passages in his _Principles of Psychology_, 1890, Vol. I,
pp. 104-112, 554-594, and Vol. II, pp. 578-592.

Another serious consideration of the matter is given by William
McDougall in his _Physiological Psychology_, 1905, Chapters VII and
VIII.

See also Thorndike's _Educational Psychology, Briefer Course_, 1914,
Chapter VI.

On the whole subject of association, see Howard C. Warren, _A History
of the Association Psychology_, 1921.


{419}

CHAPTER XVII

PERCEPTION

MENTAL LIFE CONSISTS LARGELY IN THE DISCOVERY OF FACTS NEW TO THE
INDIVIDUAL, AND IN THE RE-DISCOVERY OF FACTS PREVIOUSLY OBSERVED


You will remember the case of John Doe, who was brought before us for
judgment on his behavior, as to how far it was native and how far
acquired. We have since that time been occupied in hearing evidence on
the case, and after mature consideration have reached a decision which
we may formulate as follows: that this man's behavior is primarily
instinctive or native, but that new attachments of stimulus and
response, and new combinations of responses, acquired in the process
of learning, have furnished him with such an assortment of habits and
skilled acts of all sorts that we can scarcely identify any longer the
native reactions out of which his whole behavior is built. That
decision being reached, we are still not ready to turn the prisoner
loose, but wish to keep him under observation for a while longer, in
order to see what use he makes of this vast stock of native and
acquired reactions. We wish to know how an individual, so equipped,
behaves from day to day, and meets the exigencies of life. Such, in
brief, is the task we have still before us.

Accordingly, one fine morning we enter our prisoner's sleeping
quarters, and find him, for once, making no use of his acquired
reactions, as far as we can see, and utilizing but a small fraction of
his native reactions. He is, in short, asleep. We ring a bell, and he
stirs uneasily. We {420} ring again, and he opens his eyes sleepily
upon the bell, then spies us and sits bolt upright in bed. "Well, what
. . ." He throws into action a part of his rather colorful vocabulary.
He evidently sees our intrusion in an unfavorable light at first, but
soon relaxes a little and "supposes he must be late for breakfast".
Seeing our stenographer taking down his remarks, he is puzzled for a
moment, then breaks into a loud laugh, and cries out, "Oh! This is
some more psychology. Well, go as far as you like. It must have been
your bell I heard in my dream just now, when I thought I saw a lot of
cannibals beating the tom-tom". Having now obtained sufficient data
for quite a lengthy discussion, we retire to our staff room and
deliberate upon these manifestations.

"The man perceives", we agree. "By the use of his eyes and ears he
discovered facts, and interpreted them in the light of his previous
experience. In knowing the facts, he also got adjusted to them and
governed his actions by them. But notice--a curious thing--how his
perception of the facts progressed by stages from the vague and
erroneous to the correct and precise. Before he was fully awake, he
mistook the bell for a tom-tom; then, more fully aroused, he knew the
bell. Ourselves he first saw as mere wanton intruders, then as
cheerful friends who wished him no ill; finally he saw us in our true
character as investigators of his behavior."

Following our man through the day's work and recreation, we find a
large share of his mental activity to consist in the perception of
facts. We find that he makes use of the facts, adjusting himself to
them and also shaping them to suit himself. His actions are governed
by the facts perceived, at the same time that they are governed by his
own desires. Ascertaining how the facts stand, he takes a hand and
manipulates them. He is constantly coming to know {421} fresh facts,
and constantly doing something new with them. His life is a voyage of
discovery, and at the same time a career of invention.

Discovery and invention!--high-sounding words, still they are
applicable to everyday life. The facts observed may not be absolutely
new, but at least they have always to be verified afresh, since action
needs always to take account of present reality. The invention may be
very limited in scope, but seldom does an hour pass that does not call
for doing something a little out of the ordinary, so as to escape from
a fresh trap or pluck fruit from a newly discovered bough. All of our
remaining chapters might, with a little forcing, be pigeonholed under
these two great heads. Discovery takes its start with the child's
instinctive exploratory activity, and invention with his manipulation,
and these two tendencies, perhaps at bottom one, remain closely
interlinked throughout.


Some Definitions

_Perception_ is the culmination of the process of discovery. Discovery
usually requires exploration, a search for facts; and it requires
attention, which amounts to finding the facts or getting them
effectively presented; and perception then consists in knowing the
presented facts.

When the facts are presented to the senses, we speak of "sense
perception". If they are presented to the eye, we speak of visual
perception; if to the ear, of auditory perception, etc. But when we
speak of a fact as being "presented" to the eye or ear, we do not
necessarily mean that it is directly and completely presented; it may
only be indicated. We may have before the eyes simply a _sign_ of some
fact, but perceive the fact which is the _meaning_ of the sign. We
look out of the window and "see it is wet to-day", though wetness is
something to be felt rather than seen; {422} having previously
observed how wet ground looks, we now respond promptly to the visual
appearance by knowing the indicated state of affairs. In the same way,
we say that we "hear the street car", though a street car, we must
admit, is not essentially a noise. What we hear, in strictness, is a
noise, but we respond to the noise by perceiving the presence of the
car. Responding to a stimulus presented to one sense by perceiving a
fact which could only be directly presented to another sense is
exemplified also by such common expressions as that the stone "looks
heavy", or that the bell "sounds cracked". or that the jar of fruit
"smells sour". Sense perception, then, is responding to a stimulus by
knowing some fact indicated by it either directly or indirectly.
Perception that is not sense perception occurs when the fact perceived
is not even indirectly presented to the senses at the moment. The fact
is then presented by recall; yet the fact in question is not recalled.
Recall not only gives you facts previously perceived, but may provide
the data, the stimulus, for fresh perception. Putting together two
recalled facts, you may perceive a further fact not previously known.
Remembering that you took your umbrella to the office this morning in
the rain, that it was fine when you left the office, and that you
certainly did not have the umbrella when you reached home, you
perceive that you must have left it at the office. Reading in the
paper of preparations for another polar expedition, and remembering
that both poles have already been discovered, you perceive that there
is something more in polar exploration than the mere race for the
pole. Perception of this sort amounts to "reasoning", and will be
fully considered in another chapter, while here we shall focus our
attention on sense perception.

{423}

The Difference Between Perception and Sensation

If sense perception is a response to a sensory stimulus, so is
sensation, and the question arises whether there is any genuine
difference between these two. In the instance of "hearing the street
car", the difference is fairly obvious; hearing the noise is
sensation, while knowing the street car to be there is perception.

Sensation is the first response aroused by a stimulus, or at least the
first response that is conscious. Perception is a second response,
following the sensation, and being properly a direct response to the
sensation, and only an indirect response to the physical stimulus. The
chain of events is: stimulus, response of the sense organ and sensory
nerve, first cortical response which is sensation, second cortical
response which is perception.

Conscious sensation is the response of the part of the cortex that
first receives the nerve current from the sense organ stimulated, the
response of the "sensory area" for the particular sense stimulated.
When the eye is stimulated, the nerve current first reaches a small
portion of the occipital lobe, called the visual sensory area. Without
that area there is no visual sensation. When the ear is stimulated,
the conscious sensation is the response of a small portion of the
temporal lobe called the auditory sensory area, and without this area
there is no auditory sensation. But the presence of the visual sensory
area is not enough to give the visual perception of facts, nor is the
presence of the auditory sensory area enough to give auditory
perception. The cortical regions _adjacent_ to the sensory areas are
necessary for perception; if they are destroyed, the individual may
still see, but not know the objects seen; or may still hear, but not
recognize the words or tunes that he hears. If the cortical area
destroyed is in the parietal {424} lobe, adjacent to the sensory area
for the cutaneous and kinesthetic senses, he may still "feel" objects,
but without being able to distinguish an apple from a lump of coal, or
a folded newspaper from a tin pail.

Sense perception, then, is a response of areas adjacent to the sensory
areas, and this response is aroused by nerve currents coming along
"association fibers" from the sensory areas which are first aroused
from the sense organs.

The whole chain of events, from the time the stimulus reaches the
sense organ to the time the fact is perceived, occupies only a fifth
or even a tenth of a second in simple cases, and the interval between
the beginning of the sensation to the beginning of the perception is
not over a twentieth when the fact is easily perceived. Since the
sensation usually lasts for longer than this, it overlaps the
perception in time, and the two conscious responses are so _blended_
that it is difficult or impossible for introspection to separate them.

But when an unusual fact is presented, perception may lag, though
sensation occurs promptly. We may be baffled and confused for an
instant, and have sensation without any definite perception; or, more
often, we make a rapid series of _trial and error perceptions_. In one
instance, a noise was first heard as distant thunder, and then,
correctly, as somebody walking on the floor above. In another case, a
faint sound was first taken for a bird singing, then for a distant
locomotive whistle, and finally for what it was, the tinny noise of a
piece of metal carried in the hand and brushing against the overcoat
as the person walked; this series occupied not over five seconds. On
touching an object in the dark, you may feel it as one thing and
another till some response is aroused that fits the known situation
and so satisfies you. Such trial and error perception can be observed
very frequently if one is on the watch for {425} psychological
curiosities; and it justifies the distinction between sensation and
perception, since the sensation remains virtually unchanged while
perception changes.

Another sort of shifting perception is seen in looking steadily at the
"ambiguous figures" which were considered in the chapter on attention,
the cube, staircase, and others; and the "dot figures" belong here as
well. [Footnote: See p. 252.] In these cases the stimulus arouses two
or more different perceptions, alternately, while the sensation
remains almost or quite unchanged.


Perception and Image

The experiment with ambiguous figures also gives an answer to the
question whether perception consists in the addition of recalled
memory images to the sensations aroused by the present stimulus. If
that were so, you should, when you see the upper side of the flight of
stairs, see them as wooden stairs or stone stairs, as carpeted or
varnished, with shadows on them such as appear on a real flight of
stairs, with a railing, or with some other addition of a similar
nature; and, when the appearance changes to that of the under side of
a flight of stairs, the colors, shadows, etc., should change as well.
The usual report is that no such addition can be detected, and that
the subject sees no filling-in of the picture, but simply the bare
lines--only that they seem at one moment to be the bare outline of the
upper side, and at another moment an equally bare outline of the lower
side, of a flight of stairs.

So again, when you "hear the street car", you do not ordinarily, to
judge from the reports of people who have been asked, get any visual
or kinesthetic image of the car, but you simply know the car is there.
You will quite {426} possibly get some such image, if you _dwell_ on
the fact of the car's being there, just as some persons, in talking to
a friend over the telephone, have a visual image of the friend. There
is no reason why such images should not be aroused, but the question
is whether they are essential to perception of the fact, and whether
they occur before or after the fact is perceived. Often they do not
occur, and often, when they do occur, they follow the perception of
the fact, being aroused by that perception and not constituting it.

Sometimes images are certainly aroused during the perception of a
fact, and, blending with the present rather vague sensation, add color
and filling to the picture.

Here is an instance of this which I once observed in myself, in spite
of the infrequency of my visual images. Approaching a house through a
wide field one winter night, and seeing a lamp shining out of a window
towards me, I seemed to see the yellowish light touching the high
spots in the grass around. I was surprised that the lamp should carry
so far, and the next instant saw that the light spots on the ground
were small patches of snow, lighted only from the clouded sky; and at
this the yellow tinge of the spots vanished. I must have read the
yellow color into them to fit the lamplight. The yellow was an image
blending with the actual sensation. Colors tacked on to a seen object
in this way are sometimes called "memory colors".

When this instance is considered carefully, however, it does not by
any means indicate that the image produced the perception. I responded
to the pair of stimuli--lamp shining towards me and light spots around
me--by perceiving the spots as lighted by the lamp; and the color
followed suit. I next saw the spots as snow, and the color vanished.
It was a case of trial and error perception, with color images
conforming to the perception.

Perception does not essentially consist in the recall of {427} images,
but is a different sort of response--what sort, we have still to
consider.


Perception and Motor Reaction

Possibly, we may surmise, perception is a motor response, completely
executed or perhaps merely incipient, or at least a readiness for a
certain motor response. This guess is not quite so wild as our
customary sharp distinction between knowing and doing might lead us to
think. When we say that reacting to a thing in a motor way is quite
different from merely seeing the thing, we forget how likely the child
is to do something with any object as soon as he sees what it is. We
forget also how common it is for a person, in silently reading a
word--which is perceiving the word--to whisper it or at least move his
lips. To be sure, persons who read a great deal usually get over this
habit, as the child more and more inhibits his motor response to many
seen objects. But may it not be that the motor response is simply
reduced to a minimum? Or, still better, may it not be that perceiving
an object amounts to _getting ready_ to do something with it? May not
seeing a word always be a getting ready to say it, even if no actual
movement of the vocal organs occurs? May not seeing an orange consist
in getting ready to take it, peel it, and eat it? May not perceiving
our friend amount to the same thing as getting ready to behave in a
friendly manner, and perceiving our enemy amount to the same thing as
getting on our guard against him? According to this view, perception
would be a response that adjusted the perceiver to the fact perceived,
and made him ready to do something appropriate.

In spite of the attractiveness of this theory of perception, it is
probably not the real essence of the matter. Just as perception may
change while sensation remains the same, so there may be a hesitation
between two motor responses {428} to an object, without any change in
the way it is perceived; and just as a block may occur between
sensation and perception, so also may one occur between perception of
a fact and the motor response. In other words, perception of a fact
may not spell complete readiness to act upon it. The best example of
this is afforded again by cases of localized brain injuries.

It happens, in motor aphasia, that the subject hears and understands a
spoken word--fully perceives it--and yet cannot pronounce it himself.
And at that, there need be no paralysis of the speech organs. The
brain injury has affected the motor speech-cooerdinating machinery, and
deprived the individual of the power to get ready for speaking a word,
even though he perceives it.

Analogous disabilities occur in respect to other movements. It may
happen, through injury somewhere near the motor area, though not
precisely in that area, that one who clearly perceives a seen object
is still quite incapable of handling it. He knows the object, and he
knows in an abstract way what to do with it, but how to go about it he
cannot remember. This type of disturbance is called "motor apraxia",
and, like motor aphasia, it proves that there is a preparation that
follows perception and still precedes actual movement. Paralysis of
the motor area is different; then, the subject both perceives the
object, and gets all ready to act upon it; only, the movement does not
occur.

The truth seems to be that a series of four responses occurs in the
brain, in the process of making a skilled movement dealing with a
perceived object. First, sensation; second, perception of the object;
third, cooerdinating preparation for the act; and fourth, execution of
the act by the motor area arousing the lower motor centers and through
them the muscles. The first response is like receiving signals {429}
or code messages; the second deciphers the messages and knows the
state of affairs; the third plans action; and the fourth sends out
orders to the agents that perform the action.

The distinction between perception and preparation for action is
sometimes rather difficult to draw. The twelve o'clock whistle means
time to drop your tools, and it is hard to draw a line between knowing
the fact and beginning the act. On the other hand, when my watch tells
me the noon hour is almost over, some little time may be required
before I get into motion. Where there is no block or inhibition, the
chain of responses runs off with such speed as to seem a single
response. But a block may occur at any one of several places. It may
check the actual movement, as in the "delayed reaction", [Footnote:
See p. 76.] and in cases where we itch to do something yet check
ourselves. Here the preparation occurs, but the execution is checked.
Sometimes the block occurs between perception and preparation, when we
know a fact but find nothing to do about it or hesitate between two
ways of acting. Sometimes, also, the block occurs between sensation
and perception; a sudden loud noise will sometimes throw a person into
a momentary state of confusion during which he is unable to recognize
the noise.

Blocking of response at different stages can be illustrated very well
in the case of anger. The irritating stimulus gives a prompt fighting
reaction, unless checked at some stage. When the check prevents me
from actually striking the offending person, but leaves me clenching
my fist and gnashing my teeth, the chain of responses has evidently
gone as far as readiness for action, and been blocked between that
stage and the stage of execution. Probably the inhibitory influence
here is anticipation of bad consequences. The block may occur one
stage further back, when I say to myself that {430} I mustn't let
myself get "all riled up" since it will spoil my morning's work; here,
instead of substituting the clenched fist for actual fighting, I
substitute a bored or contemptuous attitude for the pugnacious
attitude. All this time I still am conscious of the offense done me.
But suppose something leads me to try to look at the other person's
behavior from his own point of view--then I perceive it in a different
light, and it may no longer appear a personal offense to myself. I
here get a substitute perception.

The process of blocking and substituting is the same process that we
have seen in trial and error.[Footnote: See p. 408.] The response
proving unsatisfactory, or promising to be unsatisfactory, is checked
and a substitute response found. Other elements in the situation get a
chance to exert their influence on the reaction. If perception of a
fact were absolutely the same as preparing a motor act, we could not
look over the situation, perceiving one fact after another, and
letting our adjustment for action depend on the total situation
instead of on the separate facts successively observed; nor could we
perceive one fact while preparing the motor response to another fact,
as is actually done in telegraphy, typewriting, reading aloud, and
many other sorts of skilled action. In reading aloud, the eyes on the
page keep well ahead of the voice; while one word is being pronounced,
the next word is being prepared for pronouncing, and words still
further ahead are in process of being perceived.

We conclude, accordingly, that perception of an object is not
absolutely the same thing as motor response to the object, nor even as
motor readiness to respond, although the transition from perception to
motor readiness may be so quick that the whole reaction seems a unit.
In reality, perception of the object precedes the motor adjustment,
and is one factor in determining that adjustment.

{431}

What Sort of Response, Then, Is Perception?

We can say this, that perception is knowing the fact, as distinguished
from readiness to act. We can say that perception is an adjustment to
facts as they are, while motor adjustment is a preparation for
changing the facts. Perception does not alter the facts, but takes
them as they are; movement alters the facts or produces new facts. We
can say that perception comes in between sensation and motor
preparation. But none of these statements is quite enough to satisfy
us, if we wish to know something of the machinery of perception. What
is the stimulus in perception, and what is the nature of the response?

It takes a collection of stimuli to arouse a perception. This
collection is at the same time a selection from among the whole mass
of sensory stimuli acting at any moment on the individual. Perception
is thus a fine example both of the "law of selection" and of the "law
of combination". [Footnote: See pp. 256, 263.] Perception is at once a
_combining_ response and an _isolating_ response.

We perceive a face--that means that we take the face as a unit, or
make a unitary response to the multiple stimuli coming from the face.
At the same time, in perceiving the face, we isolate it from its
background, or disregard the numerous other stimuli that are
simultaneously acting upon us. If we proceed to examine the face in
detail, we may isolate the nose and perceive that as a whole. We might
isolate still further and perceive a freckle on the nose, taking that
as a whole, or even observing separately its location, diameter, depth
of pigmentation, etc. Even if we went so far as to observe a single
speck of dust on the skin, in which case isolation would about reach
its maximum, combination would still stay in the game, for we should
either note {432} the location of the speck--which would involve
relating it to some part of the face--or we should contrast it with
the color of the skin, or in some similar way take the single stimulus
in relation with other present stimuli. Perception is always a unitary
response to an isolated assemblage of stimuli.

Consider these two opposite extremes: taking in the general effect of
the view from a mountain top, and perceiving the prick of a pin. In
the first case, combination is very much in evidence, but where is the
isolation? There is isolation, since internal bodily sensations, and
very likely auditory and olfactory sensations as well, are present but
do not enter into the view. In the case of the pin prick, isolation is
evident, but where does combination come in? It would not come into
the mere reflex of pulling the hand away, but perceiving the pin means
something more than reflex action. It means locating the sensation, or
noticing its quality or duration or something of that sort, and so
contrasting it with other sensations or relating it to them in some
way. To perceive one stimulus as related to another is to respond to
both together.

But in describing perception as a unitary response to an isolated
assemblage of stimuli, we have not differentiated it from a motor
response, for that, too, is often aroused by a few (or many) stimuli
acting together. What more can we say? In neural terms, we can only
repeat what was said before, that perception is the next response
after sensation, being a direct response to a certain combination of
sensations, and being in its turn the stimulus, or part of the
stimulus, that arouses a motor adjustment, as it may also be the
stimulus to recall of previously observed facts. In more psychological
terms, we can say that sense perception is closely bound up with
sensation, so that we seem to see the fact, or hear it, etc.; we
perceive it as present to the {433} senses, rather than as thought of
or as anticipated. Motor readiness is anticipatory, perception
definitely objective. Motor readiness is an adjustment for something
yet to be, while perception is an adjustment to something already
present.


Practised Perception

A fact perceived for the first time must needs be attended to, in
order that it may be perceived. That is, the first and original
perception of a fact is a highly conscious response. But the
perception of a fact, like any other form of response, becomes easy
with practice; the linkage of stimulus and response becomes stronger
and stronger, till finally the stimulus arouses the perceptive
response almost automatically. The familiar fact is perceived without
receiving close attention, or even without receiving any attention.
While your attention is absorbed in reading or thinking, you may
respond to the sight of the flower in a vase on your table by knowing
it to be there, you may respond to the noise of the passing street car
by knowing what that is, and you may respond to the contact of your
foot with the leg of the chair by dimly knowing what that object is. A
great deal of this inattentive perception of familiar facts is always
going on. Aside from sensation and from some of the reflexes, the
perception of familiar facts is the most practised and the easiest of
all responses.

The laws and sub-laws of learning apply perfectly to practised
perception. The more frequently, the more recently, and the more
intensely a given fact has been perceived, the more readily is it
perceived again. The more a given fact is in line with the mental set
of the moment, the more readily is it perceived. Sometimes it is so
readily perceived that we think we see it when it isn't there. If you
are hunting for a lost knife, anything remotely resembling {434} a
knife will catch your eye and for an instant be perceived as the
missing object.

The principle of _substitute stimulus_ applies remarkably well to
practised perception. The first time you perceive an object, you
observe it attentively, and expose your perceptive apparatus to the
whole collection of stimuli that the object sends your way. The next
time you need not observe it so attentively, for you make the same
perceptive response to a _part_ of the original collection of stimuli.
The response originally aroused by the whole collection of stimuli is
later aroused by a fraction of this collection. The stimulus may be
_reduced_ considerably, and still arouse the perception of the same
fact. A child is making the acquaintance of the dog. The dog barks,
and the child watches the performance. He not only sees the dog, and
hears the noise, but he _sees_ the dog _bark_, and _hears_ the dog
_bark_. This original perception is a unitary response to the
combination of sight and sound. Thereafter he does not require both
stimuli at once, but, when he hears this noise, he perceives the dog
barking, and when he sees the dog he sees an object that can bark. In
the same way, a thousand objects which furnish stimuli to more than
one of the senses are perceived as units, and, later, need only act on
a single sense to be known.

The stimulus, instead of being reduced, may be _modified_, and still
arouse the same perception as before. A face appears in the baby's
field of view, but away across the room so that it is a very small
object, visually. The face approaches and gradually becomes a larger
visual object, and the light and shadow upon it change from moment to
moment, but it remains nearly enough the same to arouse essentially
the same perception in the child. He comes to know the face at various
distances and angles and under various lights.

{435}

Again, the child holds a block in his hands, and looks at it square
on, so that it is really a rectangle in his field of view. He turns it
slightly, and now it is no longer visually a rectangle, but an oblique
parallelogram. But the change is not enough to abolish the first
perception; he sees it as the same object as before. By dint of many
such experiences, we see a book cover or a door as a rectangle, no
matter at what angle we may view it, and we know a circle for a circle
even though at most angles it is really an ellipse in the field of
view. A large share of practised perceptions belong under the head of
"response by analogy",[Footnote: See p. 406.] since they consist in
making the same response to the present stimulus that has previously
been made to a similar but not identical stimulus. If every modified
stimulus gave a new and different perception, it would be a slow job
getting acquainted with the world. A thing is never twice the same, as
a collection of stimuli, and yet, within wide limits, it is always
perceived as the same thing.


Corrected Perception

Response by analogy, however, often leads us astray, in making us
perceive a new object as essentially the same as something already
familiar. First impressions of a new object or acquaintance often need
revision, because they do not work well. They do not work well because
they are rough and ready, taking the object in the lump, with scant
attention to details which may prove to be important. It is easy to
follow the law of combination and respond to a whole collection of
stimuli, but to break up the collection and isolate out of it a
smaller collection to respond to--that is something we will not do
unless forced to it. Isolation and discrimination are uphill work.
When they occur, it is {436} because the rough and ready response has
proved unsatisfactory,

_Substitute response_ is the big factor in corrected perception, as
substitute stimulus is in practised perception. When our first
perception of an object gets us into difficulties, then we are forced
to attend more closely and find something in the object that can serve
as the stimulus to a better response. This is the process by which we
isolate, analyze, discriminate.

Our old friend, the white rat, learned to enter a door only if it bore
a yellow sign. [Footnote: See p. 304.] It was uphill work for him,
hundreds of trials being required before the discriminating response
was established; but he learned it finally. At the outset, a door was
a door to the rat, and responded to as such, without regard to the
sign. Whenever he entered a door without the sign, he got a shock, and
scurried back; and before venturing again he looked all around,
seeking, we may say, a stimulus to guide him; incidentally, he looked
at the yellow disk, and this stimulus, though inconspicuous and feeble
to a rat, finally got linked up with the entering response. The
response of first finding and then following the sign had been
substituted for the original response of simply entering.

In the same way the newly hatched chick, which at first pecks at all
small objects, caterpillars included, learns to discriminate against
caterpillars. In a practical sense, the chick, like the rat, learns to
distinguish between stimuli that at first aroused the same response.
It is in the same way that the human being is driven to discriminate
and attend to details. He is brought to a halt by the poor results of
his first rough and ready perception, scans the situation, isolates
some detail and, finding response to this detail to bring satisfactory
results, substitutes response to this {437} detail for his first
undiscriminating response to the whole object.

The child at first treats gloves as alike, whether rights or lefts,
but thus gets into trouble, and is driven to look at them more sharply
till he perceives the special characteristics of rights and lefts. He
could not describe the difference, to be sure, but he sees it well
enough for his purposes. If you ask an older person to describe this
difference, and rally him on his inability to do so, he is thus driven
to lay them side by side and study out the difference still more
precisely.

The average non-mechanical person, on acquiring an automobile, takes
it as a gift of the gods, a big total thing, simply to sit in and go.
He soon learns certain parts that he must deal with, but most of the
works remain a mystery to him. Then something goes wrong, and he gets
out to look. "What do you suppose this thing is here? I never noticed
it before". Tire trouble teaches him about wheels, engine trouble
leads him to know the engine, ignition trouble may lead him to notice
certain wires and binding-posts that were too inconspicuous at first
to attract his attention. A car becomes to him a thing with a hundred
well-known parts, instead of just one big totality.

Blocked response, closer examination, new stimulus isolated that gives
satisfactory response--such is, typically, the process of analytic
perception.


Sensory Data Serving as Signs of Various Sorts of Fact

Among facts perceived, we may list things and events, and their
qualities and relations. Under "things" we here include persons and
animals and everything that would ordinarily be called an "object".
Under "events", we include movement, change and happenings of all
sorts. Under {438} "qualities" we may include everything that can be
discovered in a thing or event taken by itself, and under "relations"
anything that can be discovered by comparing or contrasting two things
or events. The "groups" that we have several times spoken of as being
observed would here be included under "things"; but the strict logic
of the whole classification is not a matter of importance, as the only
object in view is to call attention to the great variety of facts that
are perceived.

Now the question arises, by what signs or indications these various
facts are perceived. Often, as we have seen, the fact is by no means
fully presented to the senses, and often it is far from easy for the
perceiver to tell on what signs the perception depends. He knows the
fact, but how he knows it he cannot tell. A large part of the very
extensive experimental investigation of perception has been concerned
with this problem of ferreting out the signs on which the various
perceptions are based, the precise stimuli to which the perceptions
respond.

For example, we can examine objects by feeling of them with a stick
held in the hand, and thus perceive their roughness or smoothness; but
how do we sense these facts? It seems to us as if we felt them with
the end of the stick, but that is absurd, since there are no sense
organs in the stick. It must be that we perceive the roughness by
means of sensations arising in the hand and arm, but to identify these
sensations is a much harder task than to discover the objective fact
of roughness.

Again, we distinguish the tones of two musical instruments by aid of
their overtones, but elaborate experiments were required to prove
this, since ordinarily we do not distinguish the overtones, and could
simply say that the instruments sounded differently, and let it go at
that.

Once more, consider our ability to perceive time intervals; {439} and
to distinguish an interval of a second from one of a second and a
quarter. How in the world can any one perceive time? Time is no force
that could conceivably act as a stimulus to a sense organ. It must be
some change or process that is the stimulus and that serves as the
indication of duration. Most likely, it is some muscular or internal
bodily change, but none of the more precise suggestions that have been
offered square with all the facts. It cannot be the movements of
breathing that give us our perception of time, for we can hold our
breath and still distinguish one short interval from another. It
cannot be the heart beat, for we can beat time in a rhythm that cuts
across the rate of the heart beat. When a singer is accompanying
himself on the piano, keeping good time in spite of the fact that the
notes are uneven in length, and meanwhile using his feet on the
pedals, what has he got left to beat time with? No one has located the
stimulus to which accurate time perception responds, though, in a
general way, we are pretty sure that change of one sort or another is
the datum. With longer intervals, from a minute to several hours, the
sign of duration is probably the amount happening in the interval, or
else such progressive bodily changes as hunger and fatigue.


The Perception of Space

Stimuli for the perception of location are provided by all the senses.
We perceive a taste as in the mouth, thirst as in the throat, hunger
pangs as in the stomach. To a familiar odor we may respond by knowing
the odorous substance to be close at hand. To stimulation of the
semi-circular canals we respond by knowing the direction in which we
are being turned.

We respond to sounds by knowing the direction from which they come,
and the distance from which they come; {440} but it must be confessed
that we are liable to gross errors here. To perceive the distance of
the sounding body we have to be familiar with the sound at various
distances, and our perception of distance is based on this knowledge.
As to the direction of sound, experiment has proved that we do little
more than distinguish between right and left; we are all at sea in
attempting to distinguish front from back or up from down. Apparently
the only datum we have to go by is the different stimulation given the
two ears according as the sound comes from the right or left.

The remaining senses, the cutaneous, the kinesthetic and the visual,
afford much fuller data for the perception of spatial facts. Movements
of the limbs are perceived quite accurately as to direction and
extent.

A cutaneous stimulus is located with fair exactness, though much less
exactly on such regions as the back than on the hands or lips. If you
were asked how you distinguished one point from another on the back of
the hand, you could only answer that they felt different; and if you
were further asked whether a pencil point applied to the two points of
the skin did not feel the same, you would have to acknowledge that it
did feel the same, except that it was felt in a different place. In
other words, you would not be able to identify the exact data on which
your perception of cutaneous position is based. Science has done no
better, but has simply given the name of "local sign" to the
unanalyzed sensory datum that gives a knowledge of the point
stimulated.

In handling an object, as also in walking and many other movements,
the cutaneous and kinesthetic senses are stimulated together, and
between them furnish data for the perception of many spatial facts,
such as the shape of an object examined by the hand. The spherical
shape is certainly better perceived by this combination of tactile and
kinesthetic {441} sensations than by vision, and the same is probably
true of many similar spatial facts. That is, when we see a round ball,
the visual stimulus is a substitute for the tactile and cutaneous
stimuli that originally had most to do with arousing this perception.

In part by this route of the substitute stimulus, the sense of vision
comes to arouse almost all sorts of spatial perceptions. Of itself,
the retina has "local sign" since we can tell where in the field of
view a seen object is, i.e., in what direction it is from us. This
visual perception of location is so much more exact than the cutaneous
or kinesthetic that it cannot possibly be derived from them; and the
same is true of the visual perception of difference in length, which
is one of the most accurate forms of perception. The retina must of
itself afford very complete stimuli for the perception of location and
size, as far as these are confined to the two dimensions, up-down and
right-left. But, when you stop to think, it seems impossible that the
retina should afford any data for perceiving distance in the
front-back dimension.

The retina is a screen, and the stimulus that it gets from the world
outside is like a picture cast upon a screen. The picture has the
right-left and up-down dimensions, but no front-back dimension. How,
then, does it come about, as it certainly does, that we perceive by
aid of the eye the distance of objects from us, and the solidity and
relief of objects? This problem in visual perception has received much
attention and been carried to a satisfactory solution.

Consider, first, what stimuli indicative of distance and relief could
affect a single motionless eye. The picture on the retina could then
be duplicated by a painter on canvas, and the signs of distance
available would be the same in the two cases. The painter uses
foreshortening, making a man in the picture small in proportion to his
distance away; {442} and in the same way, when any familiar object
casts a small picture on the retina, we perceive the object, not as
diminished in size, but as far away. The painter colors his near hills
green, his distant ones blue, and washes out all detail in the
latter--"aerial perspective", he calls this. His distant hill peeks
from behind his nearer one, being partially covered by it. His shadows
fall in a way to indicate the relief of the landscape. These signs of
distance also affect the single resting eye and are responded to by
appropriate spatial perceptions.

Now let the single eye move, with the head, from side to side: an
index of the distance of objects is thus obtained, additional to all
the painter has at his disposal, for the distant objects in the field
of view now seem to move with the eye, while the nearer objects slide
in the opposite direction. How much this sign is ordinarily made use
of in perceiving distance is not known; it is believed not to be used
very much, and yet it is the most delicate of all the signs of
distance. The reason why it may not be much used by two-eyed people is
that another index almost as delicate and handier to use is afforded
by binocular vision.

When both eyes are open, we have a sign of distance that the painter
does not use, though it is used in stereoscope slides. The right and
left eyes get somewhat different views of the same solid object, the
right eye seeing a little further around the object to the right, and
the left eye to the left. The disparity between the two retinal
images, due to the different angles at which they view the object, is
greatest when the object is close at hand, and diminishes to
practically zero when it is a few hundred feet away. This disparity
between the two retinal images is responded to by perception of the
distance and relief of the object.

It will be recalled [Footnote: See pp. 253-254.] that when two utterly
inconsistent {443} views are presented to the two eyes, as a red field
to one and a green field to the other, the visual apparatus balks and
refuses to see more than one at a time--the binocular rivalry
phenomenon. But when the disparate views are such as are presented to
the two eyes by the same solid object, the visual apparatus (following
the law of combination) responds to the double stimulation by getting
a single view of an object in three dimensions.


Esthetic Perception

Beauty, humor, pathos and sublimity can be perceived by the senses,
though we might debate a long time over the question whether these
characteristics are really objective, or merely our own feelings
aroused by the objects, and then projected into them. However that may
be, there is no doubt that the ability to make these responses is
something that can be trained, and that some people are blind and deaf
to beauty and humor that other people clearly perceive. Many a one
fails to see the point of a joke, or is unable to find any humor in
the situation, which are clearly perceived by another. Many a one sees
only a sign of rain in a great bank of clouds, only a weary climb in
the looming mountain.

  "A primrose by the river's brim
  A yellow primrose was to him.
  And it was nothing more."

It would not be quite fair to describe such a one as lacking in
feeling; he probably has, on sufficient stimulus, the same feelings as
another man, and it would be more exact to say that he is lacking in
perception of certain qualities and relations. He probably tends, by
nature and training, to practical rather than esthetic perception. To
see any {444} beauty in a new style of music or painting, or to sense
the humor in a new form of humorous writing, you need to be initiated,
to be trained in observing the precise qualities and relations that
are depended on for the esthetic effect. A complex situation presents
almost an unlimited range of facts that may be perceived; no one
perceives them all, and which he shall perceive depends on his nature
and training, as well as on his attitude or mental set at the moment
when the situation is presented.

Psychology has not by any means been idle in this field of esthetics;
it has developed experimental methods for determining the preferences
of individuals and of social groups. But it must be confessed that the
results offer little that can be succinctly summarized.

One curious result is that even the very simplest objects can produce
an esthetic effect. You would scarcely suppose, for example, that a
mere rectangle could produce any esthetic effect, or that it would
make any difference what exact proportions the rectangle possessed;
and yet it is found that some rectangles are preferred to others, and
that the popular choice falls upon what the art theorists have long
known as the "golden section", a rectangle with a width about
sixty-two per cent, of its length. Also, however much you may like
symmetry, you would scarcely suppose that it could make much
difference where, on a horizontal line, a little cross line should be
erected; and yet nearly every one, on being tested, will agree that
the middle is the best point. These are merely a couple of sample
results from the numerous studies in this field.


Social Perception

By the senses we perceive the motives and intentions of other people,
their sincerity, goodness, intelligence, and {445} many other traits.
We see them angry or bored, amused, full of energy. To be sure, none
of these human characteristics is directly and fully sensed, but that
is the case also with many characteristics of inanimate objects which,
nevertheless, we perceive by aid of the senses. We perceive anger or
sincerity in much the same way that we perceive moisture or smoothness
by the eye. To experience the anger of another person is a complex
experience, but a single element from this experience may come to
serve as the sign of the whole condition. A good share of the child's
undirected education consists in learning to perceive the intentions
and characteristics of other people by aid of little signs. He learns
to read the signs of the weather in the family circle, and he learns
in some measure to be a judge of men.

I once saw an instructive little incident, in which an older boy
suddenly grabbed the cap from a little boy's head, and held it out to
the driver of a passing automobile, as if giving it to him. The man
saw the joke, and drove on laughing, but the little boy took it
seriously and was quite worried for fear the man would carry off his
cap. An older child would have "seen into" the situation readily; he
could not have been teased in that way. Many social situations which
are "all Greek" to a little child are understood readily by an older
person.

It would be very valuable if psychology could succeed in analyzing out
the signs by which such a trait as intelligence or "will power" is
perceived, so as to reduce such perception to a science; but it is
very doubtful if this can be done. Some persons who probably have
themselves a keen perception of such traits have put forward systems,
based upon the shape of the face, etc. They probably think they
perceive human traits according to their systems, but the systems fail
in other hands, and are undoubtedly {446} fallacious. No good judge of
character really goes by the shape of the face; he goes by little
behavior signs which he has not analyzed out, and therefore cannot
explain to another person.

You can tell very little regarding a person's intelligence from his
photograph. This has now been pretty well established. Photographs of
persons of various degrees of intelligence are placed before those who
are reputed to be good judges, and their estimates compared with the
test ratings, and there is no correspondence. You might just as well
look at the back of the photograph as at the front.

Even with the person before you, you are likely to commit great
errors. This sort of incident has happened. A young woman is brought
before the court for delinquency, and the psychologist who has tested
her testifies that she is of low intelligence. But the young woman is
good-looking and graceful in her speech and manners, and so impresses
the judge that he dismisses as "absurd" the notion of her being
feeble-minded. He sets her free, on which she promptly gets into
trouble again. Apparently the only way to perceive intelligence is to
see a person in action, preferably under standard conditions, where
his performance can be measured; that is to say, in an intelligence
test.


Errors of Perception

The grocer needs to be assured of the accuracy of his scales, and the
chemist of the high accuracy of his chemical balance; the surveyor
needs to know about the errors that may creep into the process of
measuring the length of a line or angle. All of them, using
instruments to assist in accurate perception of facts, are concerned
about the accuracy of their instruments. Now, we all use the senses in
perceiving facts, and "errors of sense" therefore concern us {447}
all. Some of the errors committed in sense perception can be laid at
the door of the senses, and some rather belong in the sphere of
perception proper.

If you come out of a cold room into a warm room, the latter seems
warmer than it is; and if you come out of a dark room into a light
room, the latter seems brighter than it is. These errors, due to
adaptation of the temperature sense and of the retina, are properly
classed as errors of sense.

If you are taking a child's temperature with a "minute thermometer",
it is best to use your watch to tell you when the minute is up, for
the minute, when you are simply waiting for it to pass, seems very
long. But if you are "working against time", a minute seems short. The
professor is shocked when the closing bell rings, and thinks that
certainly the hour cannot be up; but some of the students have been
consulting their watches for quite a long while, being sure the hour
must be nearly over. These are scarcely errors of sense, but they are
errors of perception.

Where we tend to err in one certain direction from the truth, as in
the examples just cited, psychology speaks of a "constant error", and
evidently the knowledge of such constant errors is of importance
wherever the facts are of importance. In a court of law, a witness
often has to testify regarding the length of time occupied by some
event, and a knowledge of the constant errors in time perception would
therefore be of considerable legal importance. They would need to be
worked out in considerable detail, since they differ according to the
desires and attitude of the witness at the time of the event.

Besides constant errors, there are accidental or variable errors, due
to slight momentary causes. Both constant and variable errors can be
illustrated by a series of shots at a target. The variable error is
illustrated by the scatter of {448} the hits, and the constant error
by the excess of hits above the bull's-eye, or below, or to the right
or left. The constant error can be corrected, once you know what it
is; if results show that you tend to shoot too high, you can
deliberately aim lower. But the variability of any performance cannot
be eliminated except by long practice, and not altogether even then.


[Illustration:  Fig. 66.--Constant error and scatter in hitting at a
target. The little circle was the target, but the center of the actual
distribution of the attempts lies at the cross, which was drawn in
afterwards. The constant error could be stated by saying that the
center of distribution was so far from the target, and in such and
such a direction. The scattering of the attempts can be measured
also.]


Experimental psychology has taken great pains in measuring the
accuracy of different sorts of perception. How small a difference in
length can be perceived by the eye, how small a difference of weight
by the hand--these are sample problems in this line.

For example, to measure the fineness with which weights can be
perceived when "hefted" in the hand, you take two objects that are
alike in size and appearance but differing slightly in weight, and
endeavor to decide which is the heavier just by lifting them. You try
repeatedly and keep track of the number of errors, using this number
as a measure of the accuracy of perception. Now, if one weight were
twice as heavy as the other (one, for example, weighing 100 grams
{449} and the other 200), you would never make an error except through
carelessness; but if one were 100 and the other 120 grams, you would
make an occasional error, and the number of errors would increase as
the difference was decreased; finally, comparing 100 and 101 grams,
you would get almost as many wrong as right, so that your perception
of that small difference would be extremely unreliable.


  ERRORS IN PERCEIVING SMALL DIFFERENCES
  OF WEIGHT (From Warner Brown)

  Difference 20  16  12   8   4   8   2   1 grams

  Errors      1   2   5  18  28  81  89  44 per hundred trials

  The weights were in the neighborhood of 100 grams; each weight was
  compared with the 100-gram weight, and each such pair was lifted and
  judged 1400 times. Notice that the per cent of errors gradually
  increases as the difference becomes smaller.


The smaller the difference between two stimuli, the more numerous the
errors in perceiving it, or, the less perceptible it is, and there is
no sharp line between a difference that can be perceived and one that
is too small to be perceived. That is the first great result from the
study of the perception of small differences.

The second great result is called _Weber's law_, which can be stated
as follows: In the same sort of perception, equal relative (not
absolute) differences are equally perceptible. For example, from the
preceding table we see that 28 per cent. of errors are made in
comparing weights of 100 and 104 grams; then, according to Weber's
law, 28 per cent, of errors would also be made in comparing 200 grams
with 208, or 500 with 520, or 1000 with 1040 grams, or any pair of
weights that stood to each other in the ratio of 100 to 104. Weber's
law is only approximately true for the perception of weights, since
actually fewer errors are committed in comparing 500 and 520 than in
comparing 100 and 104 grams; but the discrepancy is not extremely
great here, and in {450} some other kinds of perception, as especially
in comparing the brightness of lights or the length of seen lines, the
law holds good over a wide range of stimuli and only breaks down near
the upper and lower extremes. We are familiar, in ordinary life, with
the general truth of Weber's law, since we know that an inch would
make a much more perceptible addition to the length of a man's nose
than to his height, and we know that turning on a second light when
only one is already lit gives a much more noticeable increase in the
light than if we add one more light when twenty are already burning.

A third great result of this line of study is that different sorts of
perception are very unequal in their fineness and reliability.
Perception of brightness is about the keenest, as under favorable
conditions a difference of one part in one hundred can here be
perceived with very few errors. Visual perception of length of line is
good for about one part in fifty, perception of lifted weight for
about one part in ten, perception of loudness of sound for about one
part in three. But the perception of small differences in the pitch of
musical tones is keener still, only that, not following Weber's law in
the least, it cannot be expressed in the same way. A person with a
good ear for pitch can distinguish with very few errors between two
tones that differ by only one vibration per second, and can perceive
this same absolute difference equally well, whether the total
vibration rate is 200, 400, or 800 vibrations per second.


Illusions

An error of perception is often called an "illusion", though this term
is commonly reserved for errors that are large and curious. When one
who is being awakened by a bell perceives it as a tom-tom, that is an
illusion. An {451} illusion consists in responding to a sensory
stimulus by perceiving something that is not really there. The
stimulus is there, but not the fact which it is taken to indicate.
Illusion is false perception.

The study of illusions is of value, not only as showing how far a
given kind of perception can be trusted, but also as throwing light on
the process of perception. When a process goes wrong, it sometimes
reveals its inner mechanism more clearly than when everything is
running smoothly. Errors of any kind are meat to the psychologist.

Illusions may be classified under several headings according to the
factors that are operative in causing the deception.

1. Illusions due to peculiarities of the sense organs.

Here the stimulus is distorted by the sense organ and so may easily be
taken as the sign of an unreal fact.

Separate the points of a pair of compasses by about three-quarters of
an inch, and draw them across the mouth, one point above it and the
other below; you will get the illusion of the points separating as
they approach the middle of the mouth (where the sensory nerve supply
is greatest), and coming together again as they are drawn to the cheek
at the other side.

Under this same general head belong also after-images and contrast
colors, and also double vision whenever for any reason the two eyes
are not accurately converged upon an object. The fact that a vertical
line appears longer than an equal horizontal is supposed to depend
upon some peculiarity of the retina. Aside from the use of this class
of illusions in the detailed study of the different senses, the chief
thing to learn from them is they so seldom are full-fledged illusions,
because they are ignored or allowed for, and not taken as the signs of
facts. An after-image would constitute a genuine illusion if it were
taken for some real {452} thing out there; but as a matter of fact,
though after-images occur very frequently--slight ones practically
every time the eyes are turned--they are ignored to such an extent
that the student of psychology, when he reads about them, often thinks
them to be something unusual and lying outside of his own experience.
The same is true of double images. This all goes to show how strong is
the tendency to disregard mere sensation in the interest of getting
objective facts.

2. Illusions due to preoccupation or mental set.

When an insane person hears the creaking of a rocking-chair as the
voice of some one calling him bad names, it is because he is
preoccupied with suspicion. We might almost call this an
hallucination,[Footnote: See p. 375.] since he is projecting his own
auditory images and taking them for real sensations; it is, at any
rate, an extreme instance of illusion. In a milder form, similar
illusions are often momentarily present in a perfectly normal person,
as when he is searching for a lost object and thinks he sees it
whenever anything remotely similar to the desired object meets his
eyes; or as when the mother, with the baby upstairs very much on her
mind, imagines she hears him crying when the cat yowls or the
next-door neighbors start their phonograph. The ghost-seeing and
burglar-hearing illusions belong here as well. The mental set
facilitates responses that are congruous with itself.

3. Illusions of the response-by-analogy type.

This is probably the commonest source of everyday illusions, and the
same principle, as we have seen, is operative in a host of correct
perceptions. Perceiving the obliquely presented rectangle as a
rectangle is an example of correct perception of this type. Perceiving
the buzzing of a fly as an aeroplane is the same sort of response only
that it happens to be incorrect. If the present stimulus has something
in {453} common with the stimulus which has in the past aroused a
certain perception, we may make the same response now as we did
before--especially, of course, if the present mantel set favors this
response.


[Illustration: Fig. 67.--The Ladd-Franklin illusion of monocular
perspective. Close one eye, and hold the book so that the other eye is
at the common center from which the lines radiate; this center is
about 5 inches from the figure. Hold the book horizontally, and just a
little below the eye.]


A good instance of this type is the "proofreader's illusion", so
called, perhaps, because the professional proofreader is less subjcet
to it than any one else. The one most subject to it is the author of a
book, for whom it is almost impossible to find every misspelled word
and other typographical error in reading the proof. Almost every book
comes out with a few such errors, in spite of having been scanned
repeatedly by several people. A couple of misprints have purposely
been left in the last few lines for the reader's benefit. If the word
as printed has enough resemblance to the right word, it arouses the
same percept and enables the reader to get the sense and pass on
satisfied. {454} Before we began to pore over books and pictures, the
lines that we saw usually were the outlines of solid objects, and now
it requires only a bare diagram of lines to arouse in us the
perception of a solid object seen in perspective. An outline drawing,
like those of the cube and staircase used to illustrate ambiguous
perspective, is more readily seen as a solid object than as a flat
figure.


[Illustration: Fig. 68.--Aristotle's illusion.]


Another illusion of this general type dates away back to Aristotle.
Cross two fingers, perhaps best the second and third, and touch a
marble with the crossed part of both fingers, and it seems to be two
marbles; or, you can use the side of your pencil as the stimulus. In
the customary position of the fingers, the stimuli thus received would
mean two objects.

A much more modern illusion of the same general type is afforded by
the moving pictures. The pictures do not actually show an object in
motion; they simply show the object in a series of motionless
positions, caught by instantaneous photography. The projector shows
the series of snap-shots in rapid succession, and conceals them by a
shutter while they are shifted, so as to avoid the blur that would
occur if the picture were itself moved before the eyes. But the series
of snap-shots has so much in common with the visual stimulus got from
an actually present moving object that we make the same perceptive
response. {455} The same illusion in a rudimentary form can be
produced by holding the forefinger upright three or four inches in
front of the nose, and looking at it while winking first the one eye
and then the other. Looked at with the right eye alone it appears to
be more to one side and looked at with the left eye alone it appears
to be more to the other side; and when the one eye is closed and the
other simultaneously opened, the finger seems actually to move from
one position to the other.


[Illustration: Fig. 69.--The pan illusion. The two pan-shaped outlines
are practically identical, but it is hard to compare the corresponding
sides--hard to isolate from the total figure just the elements that
you need to compare.]


4. Illusions due to imperfect isolation of the fact to be perceived.

Here belong, probably, most of the illusions produced in the
psychological laboratory by odd combinations of lines, etc. A figure
is so drawn as to make it difficult to isolate the fact to be
observed, and when the observer attempts to perceive it, he falls into
error. He thinks he is perceiving one fact, when he is perceiving
another. The best example is the Mueller-Lyer figure, in which two
equal lines are embellished with extra lines at their ends; you are
supposed to perceive the lengths of the two main lines, but you are
very apt to take the whole figure in the rough and perceive the
distances between its chief parts. You do not succeed in isolating the
precise fact you wish to observe.

{456}

The Mueller-Lyer Illusion

The most familiar form of this striking illusion is made with arrow
heads, thus


[Illustration: Inward and outward arrowheads on two equal length lines.]


In attempting to compare the two horizontal lines one is confused so
as to regard the line with outward-extending obliques longer than that
with inward-extending obliques, though, measured from point to point,
they are equal. The same illusion occurs in a variety of similar
figures, such as


[Illustration: Inward and outward arrowheads.]


where the main lines are not drawn, but the distances from point to
point are to be compared; or such as


[Illustration: Inward and outward solid arrowheads.]


where the two distances between points are again to be compared.
Angles, however, are not necessary to give the illusion, as can be
seen in this figure


[Illustration: Half circles with similar spacing.]


or in this


[Illustration: Full circles with similar spacing.]


In the last the lengths to be compared extend (_a_) from the
right-hand rim of circle 1 to the left-hand rim of circle 2, and (_b_)
from this last to the right-hand rim of circle 3. The same illusion
can be got with squares, or even with capital letters as

[Illustration: Upper case E with similar spacing and the center letter
reversed.]


or


[Illustration: Upper case R with similar spacing and the center letter
reversed.]


or


[Illustration: Upper case L E D with similar spacing and the center
letter reversed.]


where the distances between the main vertical lines are to be
compared.

Here is an another form of the same illusion


[Illustration: Two sets of three parallel horizontal lines. In the first
set the center line is longest. In the second set the center line is
shortest, but the same length as the first center line.]


the middle lines being affected by those above and below.

{457}

Though these illusions seem like curiosities, and far from every-day
experience, they really do enter in some degree into almost every
figure that is not perfectly square and simple.


[Illustration: Fig. 70.--The Poggendorf illusion. Are the two obliques
parts of the same straight line?]


Any oblique line, any complication of any sort, is pretty sure to
alter the apparent proportions and directions of the figure. A broad
effect, a long effect, a skewed effect, may easily be produced by
extra lines suitably introduced into a dress, into the front of a
building, or into a design of any sort; so that the designer needs to
have a practical knowledge of this type of illusion.

Extra lines have an influence also upon esthetic perception. The
esthetic effect of a given form may be quite altered by the
introduction of apparently insignificant extra lines.

{458}


[Illustration: Fig. 71.--The barber-pole illusion. The rectangle
represents a round column, around which runs a spiral, starting at
_a_. Which of the lines, 1, 2, 3, 4, and 5, comes closest to being a
continuation of _a?_]


Esthetic perception is very much subject to the law of combination,
and to the resulting difficulty of isolation.

One of the most interesting illusions, not being visual, can {459}
only be described and not demonstrated here.


  [Illustration: Fig. 72.--By aid of this simple figure, the
  Poggendorf and barber-pole illusions can be seen to be instances of
  the Mueller-Lyer illusion, Try to bisect the horizontal line in this
  figure. The oblique line at the right tends to displace the
  right-hand end of the horizontal to the right, while the oblique at
  the left tends to displace the left-hand end of the horizontal also
  to the right. Similar displacements account for the Poggendorf and
  barber-pole illusions.]


  [Illustration: Fig. 73.--The Zoellner illusion. The long lines are
  really parallel. The illusion is increased by holding the figure so
  that these main lines shall be neither vertical nor horizontal. It
  is more difficult to "deceive the eye" in regard to the direction of
  vertical and horizontal lines, than in regard to the direction of
  oblique lines. This illusion must be related in some way to the
  Mueller-Lyer and Poggendorf illusions, since the elements employed in
  constructing the three figures are so much the same.

  If you treat this figure according to the directions given for Fig.
  67, and sight along the obliques, you get an illusion of
  perspective.]


It is called the "size-weight illusion", and may be said to be based
on the old catch, "Which is heavier, a pound of lead or a pound of
feathers?" Of course, we shrewdly answer, a pound's {460} a pound. But
lift them and notice how they feel! The pound of lead feels very much
heavier. To reduce this illusion to a laboratory experiment, you take
two round wooden pill-boxes, one several times as large as the other,
and load them so that they both weigh the same; then ask some one to
lift them and tell which is the heavier. He will have no doubt at all
that the smaller box is the heavier; it may seem two or three times as
heavy. Young children, however, get the opposite illusion,
assimilating the weight to the visual appearance; but older persons
switch over to the contrast effect, and perceive in opposition to the
visual appearance. What seems to happen in the older person is a motor
adjustment for the apparent weights, as indicated by their visual
appearance, with the result that the weight of larger size is lifted
more strongly than the weight of smaller size; so that the big one
comes up easily and seems light, the little one slowly and seems
heavy.


{461}

EXERCISES


1. Outline the chapter.

2. Show that the law of combination accounts both for many
   correct perceptions, and for many illusions.

3. Through which of the senses are spatial facts best perceived?

4. "At first, the baby very likely perceives a ball simply as something
   for him to handle and throw; but, through the medium of blocked
   response, he comes to perceive it more objectively, i.e., as an
   object related to other objects, and not simply related to
   himself." Explain and illustrate this statement.

5. Give an example from the field of auditory perceptions where
   "isolation" is very much in evidence.

6. Can you see any law analogous to Weber's law in the field of
   financial profit and loss? Does a dollar gained or lost _seem_ the
   same amount, without regard to the total amount possessed?

7. Trial and error perception. Go about the room with closed eyes,
   and identify objects by touching them with the hands. Notice
   whether your first impression gives place to corrected impressions.

8. Perception of form by "active" and "passive" touch. With
   the eyes closed, try to distinguish objects of different shapes (a)
   by letting them simply rest upon the skin, and (b) by handling
   them. What senses cooeperate in furnishing data for "active touch"?

9. Binocular parallax, or the differing views of the same solid object
   obtained by the two eyes. Hold a small, three-dimensional object a
   foot in front of the face, and notice carefully the view of it
   obtained by each eye separately. A pencil, pointing towards the
   face, gives very different views. What becomes of the two monocular
   views when both eyes are open at once?

10. Binocular compared with monocular perception of "depth"
    or distance away. Take a pencil in each hand, and bring the points
    together a foot in front of the face, while only one eye is open.
    When the points seem to be nearly touching, open the other eye,
    and see whether the two points still seem to be close together.
    Repeat.


REFERENCES

Discussions of perception that are in some respects fuller than the
present chapter can be found in C. H. Judd's _Psychology, General
Introduction_, 2nd edition, 1917, pp. 162-194; in Titchener's
_Textbook of Psychology_, 1909, pp. 303-373; and in Warren's _Human
Psychology_, 1919, pp. 232-269.


{462}


CHAPTER XVIII

REASONING

THE PROCESS OF MENTAL, AS DISTINGUISHED FROM MOTOR EXPLORATION

We are still on the general topic of "discovery". Indeed, we are still
on the topic of perception; we come now to that form of perception
which is different from sense perception. The reasoner is an explorer,
and the culmination of his explorations is the perception of some fact
previously unknown to him.

Reasoning might be described as mental exploration, and distinguished
from purely motor exploration of the trial and error variety. Suppose
you need the hammer, and go to the place where it is kept, only to
find it gone. Now if you simply proceed to look here and there,
ransacking the house without any plan, that would be motor
exploration. But if, finding this trial and error procedure to be
laborious and almost hopeless, you sit down and think, "Where can that
hammer be? Probably where I used it last!" you may recall using it
for a certain purpose, in a certain place, go there and find it. You
have substituted mental exploration of the situation for purely motor
exploration, and saved time and effort. Such instances show the use of
reasoning, and the part it plays in behavior.

The _process_ of reasoning is also illustrated very well in these
simple cases. It is an exploratory process, a searching for facts. In
a way, it is a trial and error process. If you don't ransack the
house, at least you ransack your memory, in search for facts that will
assist you. You recall this fact {463} and that, you turn this way and
that, mentally, till some fact is recalled that serves your need. No
more in reasoning than in motor exploration can you hope to go
straight to the desired goal.


Animal and Human Exploration

Is man the only reasoning animal? The experimental work on animal
learning, reviewed in one of our earlier chapters, was begun with this
question in mind. Previous evidence on this point had been limited to
anecdotes, such as that of the dog that was found opening a gate by
lifting the latch with his nose, and was supposed to have seen men
open the gate in this way, and to have _reasoned_ that if a man could
do that, why not a dog? The objection to this sort of evidence is that
the dog's manner of acquiring the trick was not observed. Perhaps he
reasoned it out, and perhaps he got it by accident--you cannot tell
without watching the process of learning. You must experiment, by
taking a dog that does not know the trick, and perhaps first "showing
him" how to open the gate by lifting the latch; but it was found that
dogs and cats, and even monkeys, could not learn the trick in this
way. If, however, you placed a dog in a cage, the door of which could
be opened by lifting a latch, and motivated the dog strongly by having
him hungry and placing food just outside, then the dog went to work by
trial and error, and lifted the latch in the course of his varied
reactions; and if he were placed back in the cage time after time, his
unsuccessful reactions were gradually eliminated and the successful
reaction was firmly attached to the situation of being in that cage,
so that he would finally lift the latch without any hesitation.

The behavior of the animal does not look like reasoning. For one
thing, it is too impulsive and motor. The typical {464} attitudes of
the reasoner, whether "lost in thought" or "studying over things", do
not appear in the dog, or even in the monkey, though traces of them
may perhaps be seen in the chimpanzee and other manlike apes. Further,
the animal's learning curve fails to show sudden improvements such as
in human learning curves follow "seeing into" the problem. In short,
there is nothing to indicate that the animal recalls facts previously
observed or sees their bearing on the problem in hand. He works by
motor exploration, instead of mental. He does not search for
"considerations" that may furnish a clue.

The behavior of human beings, placed figuratively in a cage, sometimes
differs very little from that of an animal. Certainly it shows plenty
of trial and error and random motor exploration; and often the puzzle
is so blind that nothing but motor exploration will bring the
solution. What the human behavior does show that is mostly absent from
the animal is (1) attentive studying over the problem, scrutinizing it
on various sides, in the effort to find a clue; (2) thinking,
typically with closed eyes or abstracted gaze, in the effort to recall
something that may bear on the problem; and (3) sudden "insights" when
the present problem is seen in the light of past experience.

Though reason differs from animal trial and error in these respects,
it still is a tentative, try-and-try-again process. The right clue is
not necessarily hit upon at the first try; usually the reasoner finds
one clue after another, and follows each one up by recall, only to get
nowhere, till finally he notices a sign that recalls a pertinent
meaning. His exploration of the situation, though carried on by aid of
recalled experience instead of by locomotion, still resembles finding
the way out of a maze with many blind alleys. In short, reasoning may
be called a trial and error process in the sphere of mental reactions.

{465}

The reader familiar with geometry, which is distinctly a reasoning
science, can readily verify this description. It is true that the
demonstrations are set down in the book in a thoroughly orderly
manner, proceeding straight from the given assumption to the final
conclusion; but such a demonstration is only a dried specimen and does
not by any means picture the living mental process of reasoning out a
proposition. Solving an "original" is far from a straight-forward
process. You begin with a situation (what is "given") involving a
problem (what is to be proved), and, studying over this lay-out you
notice a certain fact which looks like a clue; this recalls some
previous proposition which gives the significance of the clue, but
often turns out to have no bearing on the problem, so that you shift
to another clue; and so on, by what is certainly a trial and error
process, till some fact noted in the situation plus some knowledge
recalled by this fact, taken together, reveal the truth of the
proposition.


Reasoning Culminates in Inference

When you have described reasoning as a process of mental exploration,
you have told only half the story. The successful reasoner not only
seeks, but finds. He not only ransacks his memory for data bearing on
his problem, but he finally "sees" the solution clearly. The whole
exploratory process culminates in a perceptive reaction. What he
"sees" is not presented to his senses at the moment, but he "sees that
something _must_ be so". This kind of perception may be called
_inference_.

To bring out distinctly the perceptive reaction in reasoning, let us
cite a few very simple cases. Two freshmen in college, getting
acquainted, ask about each other's fathers and find that both are
alumni of this same college. "What class was your father in?" "In the
class of 1900. And {466} yours?" "Why, he was in 1900, too. Our
fathers were in the same class; they must know each other!" Here two
facts, one contributed by one person and the other by another person,
enable both to perceive a third fact which neither of them knew
before. Inference, typically, is a response to two facts, and the
response consists in perceiving a third fact that is bound up in the
other two.

You do not infer what you can perceive directly by the senses. If Mary
and Kate are standing side by side, you can _see_ which is the taller.
But if they are not side by side, but Mary's height is given as so
much and Kate's as an inch more, then from these two facts you know,
by inference, that Kate is taller than Mary.

"Have we set the table for the right number of people?" "Well, we can
see when the party comes to the table." "Oh! but we can tell now by
counting. How many are there to be seated? One, two, three--fifteen in
all. Now count the places at table--only fourteen. You will have to
make room for one more." This reducing of the problem to numbers and
then seeing how the numbers compare is one very simple and useful kind
of inference.

Indirect comparison may be accomplished by other similar devices. I
can reach around this tree trunk, but not around that, and thus I
perceive that the second tree is thicker than the first, even though
it may not look so. If two things are each found to be equal to a
third thing, then I see they must be equal to each other; if one is
larger than my yardstick and the other smaller, then I see they must
be unequal.

Of the two facts which, taken together, yield an inferred fact, one is
often a general rule or principle, and the inference then consists in
seeing how the general rule applies to a special case. A dealer offers
you a fine-looking diamond ring for five dollars, but you recall the
rule that "all genuine diamonds are expensive", and perceive that this
{467} diamond must be an imitation. This also is an instance of
indirect comparison, the yardstick being the sum of five dollars; this
ring measures five dollars, but any genuine diamond measures more than
five dollars, and therefore a discrepancy is visible between this
diamond and a genuine diamond. You can't see the discrepancy by the
eye, but you see it by way of indirect comparison, just as you
discover the difference between the heights of Mary and Kate by aid of
the yardstick.

If all French writers are clear, then Binet, a French writer, must be
clear. Here "French writers" furnish your yardstick. Perhaps it would
suit this case a little better if, instead of speaking of indirect
comparison by aid of a mental yardstick, we spoke in terms of
"relations". When you have before your mind the relation of A to M,
and also the relation of B to M, you may be able to see, or infer, a
relation between A and B. M is the common point of reference to which
A and B are related. Binet stands in a certain relation to "French
writers", who furnish the point of reference; that is, he is one of
them. Clear writing stands in a certain relation to French writers,
being one of their qualities; from which combination of relations we
perceive clear writing as a quality of Binet.

Just as an illusion is a false sense perception, so a false inference
is called a "fallacy". One great cause of fallacies consists in the
confused way in which facts are sometimes presented, resulting in
failure to see the relationships clearly. If you read that

  "Smith is taller than Brown; and
  Jones is shorter than Smith; and therefore
  Jones is shorter than Brown,"

the mix-up of "taller" and "shorter" makes it difficult to get the
relationships clearly before you, and you are likely {468} to make a
mistake. Or again, if Mary and Jane both resemble Winifred, can you
infer that they resemble each other? You are likely to think so at
first, till you notice that resemblance is not a precise enough
relation to serve for purposes of indirect comparison. Mary may
resemble Winifred in one respect, and Jane may resemble her in another
respect, and there may be no resemblance between Mary and Jane.

Or, again,

  "All French writers are clear; but
  James was not a French writer; and therefore
  James was not a clear writer,"

may cause some confusion from failure to notice that the relation
between French writers and clear writing is not reversible so that we
could turn about and assert that all clear writers were French.

The reasoner needs a clear head and a steady mental eye; he needs to
look squarely and steadily at his two given statements in order to
perceive their exact relationship. Diagrams and symbols often assist
in keeping the essential facts clear of extraneous matter, and so
facilitate the right response.

To sum up: the process of reasoning culminates in two facts being
present as stimuli, and the response, called "inference", consists in
perceiving a third fact that is implicated in the two stimulus-facts.
It is a good case of the law of combination, and at the same time it
is a case where "isolation" is needed, otherwise the response will be
partly aroused by irrelevant stimuli, and thus be liable to error.


Varieties of Reasoning

Reasoning as a whole is a process of mental exploration culminating in
inference. Now, without regard to possible {469} variations of the
perceptive response of inference, there are at least different
varieties of the exploratory process leading up to inference. The
situation that arouses reasoning differs from one case to another, the
motive for engaging in this rather laborious mental process differs,
and the order of events in the process differs. There are several main
types of reasoning, considered as a process of mental exploration.


1. Reasoning out the solution of a practical problem.

A "problem" is a situation for which we have no ready and successful
response. We cannot successfully respond by instinct or by previously
acquired habit. We must _find out_ what to do. We explore the
situation, partly by the senses and actual movement, partly by the use
of our wits. We observe facts in the situation that recall previous
experiences or previously learned rules and principles, and apply
these to the present case. Many of these clues we reject at once as of
no use; others we may try out and find useless; some we may think
through and thus find useless; but finally, if our exploration is
successful, we observe a real clue, recall a pertinent guiding
principle, and see the way out of our problem.

Two boys went into the woods for a day's outing. They climbed about
all the morning, and ate their lunch in a little clearing by the side
of a brook. Then they started for home, striking straight through the
woods, as they thought, in the direction of home. After quite a long
tramp, when they thought they should be about out of the woods, they
saw clear space ahead, and, pushing forward eagerly, found themselves
in the same little clearing where they had eaten their lunch!
Reasoning process No. 1 now occurred: one of the boys _recalled_ that
when traversing the woods without any compass or landmark, the
traveller is very likely to go in a circle; inference, "That is what
we have done and {470} we probably shall do the same thing again if we
go ahead. We may as well sit down and think it over."

Mental exploration ensued. "How about following the brook?" "That
won't do, for it flows down into a big swamp that we couldn't get
through". "How about telling directions by the sun?" "But it has so
clouded over that you can't tell east from west, or north from south."
"Yes, those old clouds! How fast they are going! They seem to go
straight enough." "Well, say! How about following the clouds? If we
keep on going straight, in any direction, for a couple of hours, we
shall surely get out of the woods somewhere." This seems worth trying
and actually brings the boys out to a road where they can inquire the
way home.

What we find in this case is typical of problem solution. First, a
desire is aroused, and it facilitates the observation and recall of
facts relevant to itself. One pertinent fact is observed, another
pertinent fact, or rule, is recalled; and in these two taken together
the key to the problem is found.


2. Rationalization or self-justification.

While in the preceding case reasoning showed what to do, here it is
called upon to justify what has been done, or what is going to be done
anyway. The question is, what reason to assign for the act; we feel
the need of meeting criticism, either from other people or from
ourselves. The real motive for the act may be unknown to ourselves, as
it often is unless we have made a careful study of motives; or, if
known, it may not be such as we care to confess. We require a
_reasonable_ motive, some acceptable general principle that explains
our action.

A child is unaccountably polite and helpful to his mother some day,
and when asked about it replies that he simply wants to help--while
his real motive may have been to score against his brother or sister,
who is to some extent his rival.

{471}

If I have work requiring attention but want to go to the game, I
should certainly be lacking in reasoning ability if I could not find
something in the situation that made my attendance at the game
imperative. I am stale, and the game will freshen me up and make me
work better afterward. Or, I am in serious danger of degenerating into
a mere "grind", and must fight against this evil tendency. Or, my
presence at the game is necessary in order to encourage the team.

Thus, aspects of the situation that are in line with our desire bob to
the surface and suggest acceptable general principles that make the
intended action seem good and even necessary. Finding excuses for acts
already performed is a reasoning exercise of the same sort. Man is a
rationalizing animal as well as a rational animal, and his
self-justifications and excuses, ludicrous though they often are, are
still a tribute to his very laudable appreciation of rationality.


3. Explanation.

This form of reasoning, like the preceding, takes its start with
something that raises the question, "Why?" Only, our interest in the
question is objective rather than subjective. It is not our own
actions that call for explanation, but some fact of nature or of human
behavior. Why--with apologies to the Southern Hemisphere!--is it so
cold in January? The fact arouses our curiosity. We search the
situation for clues, and recall past information, just as in the
attempt to solve a practical problem. "Is it because there is so much
snow in January?" "But what, then, makes it snow? This clue leads us
in a circle." "Perhaps, then, it is because the sun shines so little
of the time, and never gets high in the sky, even at noon." That is a
pretty good clue; it recalls the general principle that, without a
continued supply of heat, cold is inevitable. To explain a phenomenon
is to deduce it from {472} an accepted general principle; to
understand it is to see it as an instance of the general principle.
Such understanding is very satisfactory, since it rids you of
uncertainty and sometimes from fear, and gives you a sense of power
and mastery.


4. Application.

The reasoning processes discussed up to this point have taken their
start with the particular, and have been concerned in a search for the
general principle that holds good of the given particular case.
Reasoning may also take its start at the other end, in a general
statement, and seek for particular cases belonging under this general
rule. But what can be the motive for this sort of reasoning? What is
there about a general proposition to stimulate exploration?

Several motives may be in play. First, there may be a need for
application of the general principle. Somebody whose authority you
fully accept enunciates a general proposition, and you wish to apply
it to special cases, either for seeing what practical use you can make
of it, or simply to make its meaning more real and concrete to
yourself. Your exploration here takes a different form from that thus
far described. Instead of searching a concrete situation for clues,
and your memory for general principles, you search your memory for
particular cases where the general law should apply. If all animals
are cold-blooded, excepting only birds and mammals, then fish and
frogs and lizards are cold-blooded, spiders, insects, lobsters and
worms; having drawn these inferences, your understanding of the
general proposition becomes more complete.


5. Doubt.

A general proposition may stimulate reasoning because you doubt it,
and wish to find cases where it breaks down. Perhaps somebody makes
the general statement whose authority you do not accept; perhaps he
says it in an assertive way that makes you want to take him down {473}
a peg. Perhaps you are in the heat of an argument with him, so that
every assertion he may make is a challenge. You search your memory for
instances belonging under the doubted general statement, in the hope
of finding one where the general statement leads to a result that is
contrary to fact. "You say that all politicians are grafters. Theodore
Roosevelt was a politician, therefore, according to you, he must have
been a grafter. But he was not a grafter, and you will have to take
back that sweeping assertion."


6. Verification.

This same general type of reasoning, which takes its start with a
general proposition, and explores particular instances in order to see
whether the proposition, when applied to them, gives a result in
accordance with the facts, has much more serious uses; for this is the
method by which a _hypothesis_ is tested in science. A hypothesis is a
general proposition put forward as a guess, subject to verification.
If it is thoroughly verified, it will be accepted as a true statement,
a "law of nature", but at the outset it is only a guess that may turn
out to be either true or false. How shall its truth or falsity be
demonstrated? By deducing its consequences, and testing these out in
the realm of observed fact.

An example from the history of science is afforded by Harvey's
discovery of the circulation of the blood, which was at first only a
hypothesis, and a much-doubted one at that. If the blood is driven by
the heart through the arteries, and returns to the heart by way of the
veins, then the flow of blood in any particular artery must be away
from the heart, and in any particular vein towards the heart. This
deduction was readily verified. Further, there should be little tubes
leading from the smallest arteries over into the smallest veins, and
this discovery also was later verified, when the invention of the
microscope made observation of the capillaries possible. Other
deductions also were verified, {474} and in short all deductions from
the hypothesis were verified, and the circulation of the blood became
an accepted law.

Most hypotheses are not so fortunate as this one; most of them die by
the wayside, since it is much easier to make a guess that shall fit
the few facts we already know than to make one that will apply
perfectly to many other facts at present unknown. A hypothesis is a
great stimulus to the discovery of fresh facts. Science does not like
to have unverified hypotheses lying around loose, where they may trip
up the unwary. It is incumbent on any one who puts forward a
hypothesis to apply it to as many special cases as possible, in order
to see whether it works or not; and if the propounder of the
hypothesis is so much in love with it that he fails to give it a
thorough test, his scientific colleagues are sure to come to the
rescue, for they, on the whole, would be rather pleased to see the
other fellow's hypothesis come to grief. In this way, the rivalry
motive plays a useful part in the progress and stabilizing of science.


Deductive and Inductive Reasoning

When you are sure at the outset of your general proposition, and need
only to see its application to special cases, your reasoning is said
to be "deductive". Such reasoning is specially used in mathematics.
But in natural science you are said to employ "inductive reasoning".
The process has already been described. You start with particular
facts demanding explanation or generalization, and try to find some
accepted law that explains them. Failing in that, you are driven to
guess at a general law, i.e., to formulate a hypothesis that will fit
the known facts. Then, having found such a conjectural general law,
you proceed to deduce its consequences; you see that, _if_ the
hypothesis is true, such and such facts must be true. Next you go out
and see whether these facts are true, and if they are, your hypothesis
{475} is verified to that extent, though it may be upset later. If the
deduced facts are not true, the hypothesis is false, and you have to
begin all over again.

The would-be natural scientist may fail at any one of several points.
First, he may see no question that calls for investigation. Everything
seems a matter-of-course, and he concludes that science is complete,
with nothing left for him to discover. Second, seeing something that
still requires explanation, he may lack fertility in guessing, or may
be a poor guesser and set off on a wild-goose chase. Helmholtz, an
extremely fertile inventor of high-grade hypotheses, describes how he
went about it. He would load up in the morning with all the knowledge
he could assemble on the given question, and go out in the afternoon
for a leisurely ramble; when, without any strenuous effort on his
part, the various facts would get together in new combinations and
suggest explanations that neither he nor any one else had ever thought
of before. Third, our would-be scientific investigator may lack the
clear, steady vision to see the consequences of his hypothesis; and,
fourth, he may lack the enterprise to go out and look for the facts
that his hypothesis tells him should be found.


Psychology and Logic

Psychology is not the only science that studies reasoning; that is the
subject-matter of logic as well, and logic was in the field long
before psychology. Psychology studies the _process_ of reasoning,
while logic checks up the result and shows whether it is valid or not.
Logic cares nothing about the exploratory process that culminates in
inference, but limits itself to inference alone.

Inference, in logical terminology, consists in drawing a conclusion
from two given premises. The two premises are the "two facts" which,
acting together, arouse the {476} perceptive response called
inference, and the "third fact" thus perceived is the conclusion.
[Footnote: The "two facts" or premises need not be true; either or
both may be assumed or hypothetical, and still they may lead to a
valid conclusion, i.e., a conclusion implicated in the assumed
premises.] Logic cares nothing as to how the premises were found, nor
as to the motive that led to the search for them, nor as to the time
and effort required, nor the difficulty encountered; these matters all
pertain to psychology.

Logic sets forth the premises and conclusion in the form of the
"syllogism", as in the old stand-by:

  Major premise: All men are mortal
  Minor premise: Socrates is a man
  Conclusion:    Therefore, Socrates is mortal

The syllogism includes three "terms", which in the above instance are
"Socrates", "mortal", and "man" or "men". Logic employs the letters,
S, P, and M to symbolize these three terms in general. S is the
"subject" (or, we might say, the "object" or the "situation") about
which something is inferred. P is the "predicate", or what is inferred
about S; and M is the "middle term" which corresponds to our
"yardstick" or "point of reference", as we used those words at the
beginning of the chapter. S is compared with P through the medium of
M; or, S and P are both known to be related to M, and therefore (when
the relations are of the right sort) they are related to each other.
It is part of the business of logic to examine what relations are, and
what are not, suitable for yielding a valid inference.

In symbols, then, the syllogism becomes:

  Major premise: M is P
  Minor premise: S is M
  Conclusion:    Therefore, S is P

{477}

Without confounding logic and psychology in the least, we may take
this symbolic syllogism as a sort of map, on which to trace out the
different exploratory processes that we have already described under
the head of "varieties of reasoning". To do so may make these
different processes stand out more distinctly.

In problem-solution, we start with S, a situation unsolved, i.e.,
without any P. P, when found, will be the solution. We explore the
situation, and find in it M; i.e., we observe that S is M. Now M
recalls our previously acquired knowledge that M is P. Having then
before us the two premises, we perceive that S is P, and are saved.

In rationalization or explanation, we know, to start with, that S is
P, and wish to know _why_ this is so. As before, we explore S, find M,
recall that M is P, and see that S, therefore, is P. Our final
conclusion is, really, that S is P because it is M; that January is
cold because it gets little sunlight.

In application, doubt or verification, we start with the major
premise, M is P, and explore our memories for an S which, being M,
should therefore be P according to our hypothesis. If we find an S
which is _not_ P, then our final conclusion is that the major premise
is false.

Reference to our "map" indicates that there might be several other
varieties of reasoning, and there are, indeed, though they are
scarcely as important as those already mentioned. Reasoning sometimes
starts with the observation of P, which means something that might
prove useful on some future occasion. Your attention is caught by
these prominent words in an advertisement, "$100 a week!" That might
come in handy on some future occasion, and you look further to see how
all that money can be attached to S, yourself on some future occasion.
You soon learn that you have only to secure subscriptions for a
certain magazine, {478} and that income may be yours. P is the money,
and M is the occupation that gives the money, while S is yourself
supposedly entering on this occupation and earning the money. This
type of reasoning is really quite common. If we see a person making a
great success of anything, we try to discover how he does it,
reasoning that if we do the same, we shall also be successful; or, if
we see some one come to grief, we try to see how it happened, so as to
avoid his mistake and so the bad consequences of that mistake. We plan
to perform M so as to secure P, or to avoid M in the hope of avoiding
P.

Sometimes, not so rarely, we have both premises handed out to us and
have only to draw the conclusion. More often, we hear a person drawing
a conclusion from only one expressed premise, and try to make out what
the missing premise can be. Sometimes this is easy, as when one says,
"I like him because he is always cheerful", from which you see that
the person speaking must like cheerful persons. But if you hear it
said that such a one "cannot be a real thinker, he is so positive in
his opinions" or that another "is unfeeling and unsympathetic from
lack of a touch of cruelty in his nature", you may have to explore
about considerably before finding acceptable major premises from which
such conclusions can be deduced.

Finally, in asking what are the _qualifications of a good reasoner_ we
can help ourselves once more by reference to the syllogistic map. To
reason successfully on a given topic, you need good major premises,
good minor premises, and valid conclusions therefrom.

(a) A good stock of major premises is necessary, a good stock of rules
and principles acquired in previous experience. Without some knowledge
of a subject, you have only vague generalities to draw upon, and your
reasoning process will be slow and probably lead only to indefinite
conclusions. {479} Experience, knowledge, memory are important in
reasoning, though they do not by any means guarantee success.

(b) The "detective instinct" for finding the right clues, and
rejecting false leads, amounts to the same as sagacity in picking out
the useful minor premises. In problem solution, you have to find both
of your premises, and often the minor premise is the first to be found
and in turn recalls the appropriate major premise. Finding the minor
premise is a matter of observation, and if you fail to observe the
significant fact about the problem, the really useful major premise
may lie dormant, known and retained but not recalled, while false
clues suggest inapplicable major premises and give birth to plenty of
reasoning but all to no purpose. Some persons with abundant knowledge
are ineffective reasoners from lack of a sense for probability. The
efficient reasoner must be a good guesser.

(c) The reasoner needs a clear and steady mental eye, in order to see
the conclusion that is implicated in the premises. Without this, he
falls into confusion and fallacy, or fails, with the premises both
before him, to get the conclusion. The "clear and steady mental eye",
in less figurative language, means the ability to check hasty
responses to either premise alone, or to extraneous features of the
situation, so as to insure that "unitary response" to the combination
of premises which constitutes the perceptive act of inference.


{480}


EXERCISES

1. Outline the chapter.

2. In what respects does the animal's solution of a problem fall
   short of reasoning?

3. Give a concrete instance of reasoning belonging under each of
   the types mentioned in the text.

4. How is it that superstitions such as that of Friday being an
   unlucky day persist? What would be the scientific way of testing
   such a belief?

5. What causes tend to arouse belief, and what to arouse doubt?

6. Introspective study of the process of thinking. Attempt to
   solve some of the following problems, and write down what you can
   observe of the process.

   (a) What is it that has four fingers and a thumb, but no flesh
       or bone?

   (b) Why does the full moon rise about sunset?

   (c) If a book and a postage stamp together cost $1.02, and
       the book costs $1.00 more than the stamp, how much does the
       stamp cost?

   (d) A riddle: "Sisters and brothers have I none, yet this
       man's father is my father's son."

   (e) Prove that a ball thrown horizontally over level ground will
       strike the ground at the same time, no matter how hard it is
       thrown.

   (f) If no prunes are atherogenous, but some bivalves are
       atherogenous, can you conclude that some prunes are not
       bivalves?

   (g) Deduce, as impersonally as possible, the opinion of you
       held by some other person.


REFERENCES

William James, _Principles of Psychology_, 1890, Vol. II, pp. 325-371.
John Dewey, _How We Think_, 1910.


{481}


CHAPTER XIX

IMAGINATION

MENTAL AS DISTINGUISHED FROM MOTOR MANIPULATION


From discovery we now turn to invention, from exploration to manipulation.

The human enterprise of exploration, which we have examined under the
headings of perception and reasoning, as well as earlier under
attention, runs the gamut from simple exploratory movements of the
sense organs in looking and listening, to the elaborate scientific
procedure followed in testing hypotheses and discovering the laws of
nature. Inventive or manipulative activity runs a similar gamut from
the child's play with his toys to the creation of a work of art, the
designing of a work of engineering, the invention of a new machine, or
the organization of a new government. The distinction between the two
lines of activity is that exploration seeks what is there, and
manipulation changes it to something else. Exploration seeks the facts
as they exist, while invention modifies or rearranges the facts. The
two enterprises go hand in hand, however, since facts must be known to
be manipulated, while on the other hand manipulation of an object
brings to light facts about it that could never be discovered by
simple examination. Invention is based on science and also contributes
to the advance of science.

Manipulation and exploration certainly go hand in hand in the little
child's behavior. The baby picks up his new toy, turns it about and
examines it on all sides, shakes it and is pleased if it makes a
noise, drops it and is pleased {482} with its bang on the floor. This
is manipulation, certainly; but it is also a way of exploring the
properties of the toy.


Beginnings of Imagination in the Child

Beginning with grasping, turning, pushing, pulling, shaking and
dropping of objects, the child's manipulation develops in several
directions. One line of development leads to _manual skill_. The child
learns to manage his toys better.

A second line of development is in the direction of
_constructiveness_. Taking things apart and putting them together,
building blocks, assembling dolls and toy animals into "families" or
"parties" setting table or arranging toy chairs in a room, are
examples of this style of manipulation, which calls less for manual
dexterity than for seeing ways in which objects can be rearranged.

_Make-believe_ is a third direction followed in the development of
manipulation. The little boy puts together a row of blocks and pushes
it along the floor, asserting that it is a train of cars. The little
girl lays her doll carefully in its bed, saying "My baby's sick; that
big dog did bite him". This might be spoken of as "manipulating things
according to the meanings attached to them", the blocks being treated
as cars, and the doll as a sick baby.

Perhaps a little later than make-believe to make its appearance in the
child is _story-telling_ the fourth type of manipulation. Where in
make-believe he has an actual object to manipulate according to the
meaning attached to it, in story-telling he simply talks about persons
and things and makes them perform in his story. He comes breathless
into the house with a harrowing tale of being pursued by a
hippopotamus in the woods; or he gives a fantastic account of the
doings of his acquaintances. For this he is sometimes accused of being
a "little liar"--as indeed he {483} probably is when circumstances
demand--and sometimes, more charitably, he is described as being still
unable to distinguish observation from imagination; but really what he
has not yet grasped is the _social_ difference between his
make-believe, which no one objects to, and his story-telling, which
may lead people astray.

Both make-believe and story-telling are a great convenience to the
child, since he is able by their means to manipulate big and important
objects that he could not manage in sober reality. He thus finds an
outlet for tendencies that are blocked in sober reality--blocked by
the limitations of his environment, blocked by the opposition of other
people, blocked by his own weakness and lack of knowledge and skill.
Unable to go hunting in the woods, he can play hunt in the yard;
unable to go to war with the real soldiers, he can shoulder his toy
gun and campaign all about the neighborhood. The little girl of four
years, hearing her older brothers and sisters talk of their school,
has her own "home work" in "joggity", and her own graduation
exercises.


Preliminary Definition of Imagination

In such ways as we have been describing, the little child shows
"imagination", or mental manipulation. In story-telling the objects
manipulated are simply _thought of_; in make-believe, though there is
actual motor manipulation of present objects, the attached _meanings_
are the important matter; and in construction there is apt to be a
_plan_ in mind in advance of the motor manipulation, as when you look
at the furniture in a room and consider possible rearrangements.

The materials manipulated in imagination are usually facts previously
perceived, and to be available for mental {484} manipulation they must
now be recalled; but they are not merely recalled--they are rearranged
and give a new result that may never have been perceived. A typical
product of imagination is composed of parts perceived at different
times and later recalled and combined, as a centaur is composed of man
and horse, or a mermaid of woman and fish. Imagination is like
reasoning in being a mental reaction; but it differs from reasoning in
being manipulation rather than exploration; reasoning consists in
seeing relationships that exist between facts, and imagination in
putting facts into new relationships. These are but rough distinctions
and definitions; we shall try to do a little better after we have
examined a variety of imaginative performances.

"Imagination" and "invention" mean very much the same mental process,
though "imagination" looks rather to the mental process itself, and
"invention" more to the outcome of the process, which is a product
having some degree of novelty and originality.

Imagination, like association and like attention, is sometimes free,
and sometimes controlled. Controlled imagination is directed towards
the accomplishment of some desired result, while free imagination
wanders this way and that, with no fixed aim. Controlled imagination
is seen in planning and designing; free imagination occurs in moments
of relaxation, and may be called "play of the imagination". The free
variety, as the simpler, will be considered first.


Our study will have more point if we first remind ourselves what are
the psychological _problems to be attacked_ in studying any mental
activity. What is the _stimulus_ and what the _response?_ These are
the fundamental questions. But the study of response breaks up into
three subordinate questions, regarding the _tendency_ that is
awakened, regarding the {485} _end-result_ obtained, and regarding the
often complex _process_ or series of responses, that leads to the
end-result.

The response in imagination we have already defined, in a general way,
as mental manipulation, and the end-result as the placing of facts
into new combinations or relationships. The stimulus consists of the
facts, either perceived at the moment or recalled from past
perception, that are now freshly related or combined. The more precise
question regarding the stimulus is, then, as to what sort of facts
make us respond in an inventive or imaginative way; and the more
precise question regarding the end-result is as to what kind of
combinations or new relationships are given to the facts--both pretty
difficult questions. In regard to process, the great question is as to
how any one can possibly escape from the beaten track of instinct and
habit, and do anything new; and in regard to tendency the question is
as to what motives are awakened in inventive activity and what
satisfaction there is in the end-result. This last question, as to
_why_ we imagine, is about the easiest to answer.


Play

Free imagination was spoken of a moment ago as a kind of play; and we
might turn this about and say that play, usually if not always,
contains an element of imagination or invention. Sometimes the child
makes up new games, very simple ones of course, to fit the materials
he has to play with; but even when he is playing a regular game, he
has constantly to adapt himself to new conditions as the
game-situation changes. We may take the child's play as the first and
simplest case of free invention and ask our questions regarding it.
What are the child's play-stimuli (toys), how does he manipulate them,
what end-results does he reach, and what satisfaction does he derive
from {486} playing? We can ask these questions, but it is not so sure
that we can answer them.

_What is a toy?_ Anything to play with. But what characteristics of an
object make it a real toy, which shall actually arouse the play
response? First, it must be such that the child can move it; and
almost anything that he can move serves, one time or another, for a
plaything. But the surest stimulus is a _new_ toy, the element of
novelty and variety being important in arousing manipulation as it is
in arousing exploration. However, to define a toy simply as something
moveable, and also new if possible, fails to satisfy the spirit of
inquiry, and about the only way to progress further is to make a long
list of toys, and classify them from the psychological point of view.
Thus we get the following classes of play-stimuli:

Little models of articles used by adults, such as tools, furniture,
dishes; and we might include here dolls and toy animals. The child's
response to this class of toys is imitative. Some psychologists have
been so much impressed with the imitative play of children and animals
(as illustrated by puppies playing fight), that they have conceived of
all play as a sort of rehearsal for the serious business of life; but
this conception does not apply very well to some of the other sorts of
toy.

Noise-makers: rattle, drum, bell, horn, whistle, fire-cracker.

Things that increase your speed of locomotion, or that move you in
unusual ways, as bicycle, skate, sled, rocking-horse, swing, seesaw,
merry-go-round. Here belong also such sports as hopping, skipping,
jumping, dancing, skipping rope, vaulting, leapfrog, whirling,
somersault. The dizzy sensation resulting from stimulation of the
semicircular canals is evidently pleasant to young children, and some
of their sports seem aimed at securing a good measure of it.

{487}

Things that increase your radius of action; balls to throw or bat, bow
and arrow, sling, mirror used to throw sunlight into a distant
person's eyes; and we might include the bicycle here as well as in the
preceding class.

Things that resist the force of gravity, floating, soaring, balancing,
ascending, instead of falling; or that can be made to behave in this
way. Here we have a host of toys and sports: balloons, soap bubbles,
kites, rockets, boats, balls that bounce, tops that balance while they
spin, hoops that balance while they roll, arrows shot high into the
sky; climbing, walking on the fence, swimming, swinging, seesaw again.

Things that move in surprising ways or that are automatic: toy
windmills, mechanical toys.

Things that can be opened and shut or readjusted in some similar way:
a book to turn the leaves of, a door to swing or to hook and unhook, a
bag or box to pack or unpack, water taps to turn on or off (specially
on).

Plastic materials, damp sand, mud, snow; and other materials that can
be worked in some way, as paper to tear or fold, stones or blocks to
pile, load or build, water to splash or pour; and we might add here
fire, which nearly every one, child or adult, likes to manage.

Finally, playmates should really be included in a list of playthings,
since the presence of a playmate is often the strongest stimulus to
arouse play.

_Such being the stimulus, what is the play response?_ It consists in
manipulating or managing the plaything so as to produce some
interesting result. The hoop is made to roll, the kite to fly, the
arrow to hit something at a distance, the blocks are built into a
tower or knocked down with a crash, the mud is made into a "pie", the
horn is sounded. Many games are variations on pursuit and capture (or
escape): tag, hide-and-seek, prisoner's base, blind {488} man's buff,
football, and we might include chess and checkers here. Wrestling,
boxing, snowballing are variations on attack and defense. A great many
are variations on action at a distance, of which instances have
already been cited from children's toys; in adult games we find here
golf, croquet, bowling, quoits, billiards, shooting. Many games
emphasize motor skill, as skipping ropes, knife, cat's cradle, usually
however with competition in skill between the different players. This
element of manual skill enters of course into nearly all games. Mental
acuteness appears in the guessing games, as well as in chess and many
games of cards. Many games combine several of the elements mentioned,
as in baseball we have action at a distance, pursuit and escape, motor
skill and activity, and a chance for "head work".


The Play Motives

Now, what is the sense of games and toys, what satisfactions do they
provide? What instincts or interests are thrown into activity? There
is no one single "play instinct" that furnishes all the satisfaction,
but conceivably every natural and acquired source of satisfaction is
tapped in one play or another. In the games that imitate fighting,
some of the joy of fighting is experienced, even though no real anger
develops. In the games that imitate pursuit and escape, some of the
joy of hunting and some of the joy of escape are awakened. In the
"kissing games" that used to be common in young people's parties when
dancing was frowned upon, and in dancing itself, some gratification of
the sex instinct is undoubtedly present; but dancing also gives a
chance for muscular activity which is obviously one source of
satisfaction in the more active games. In fact, joy in motor activity
must be counted as one of the most general sources of
play-satisfaction. Another {489} general element is the love of social
activity, which we see in dancing as well as in nearly all games and
sports. Another, akin to the mere joy in motor activity, is the love
of manipulation, with which we began this whole discussion.

The "escape motive" deserves a little more notice. Though you would
say at first thought that no one could seek fear, and that this
instinct could not possibly be utilized in play, yet a great many
amusements are based on fear. The "chutes", "scenic railways", "roller
coasters", etc., of the amusement parks would have no attraction if
they had no thrill; and the thrill means fear. You get some of the
thrill of danger, though you know that the danger is not very real.
Probably the thrill itself would not be worth much, but being quickly
followed by _escape_, it is highly satisfactory. The joy of escape
more than pays for the momentary unpleasantness of fear. The fear
instinct is utilized also in coasting on the snow, climbing, swimming,
or any adventurous sport; in all of which there is danger, but the
skilful player escapes by his own efforts. If he lost control he would
get a tumble; and that is why the sport is exciting and worth while.
He has his fear in check, to be sure, but it is awakened enough to
make the escape from danger interesting. Nothing could be much further
from the truth than to consider fear as a purely negative thing,
having no positive contribution to make to human satisfaction. Though
we try to arrange the serious affairs of life so as to avoid danger as
much as possible, in play we seek such dangers as we can escape by
skilful work. The fascination of gambling and of taking various risks
probably comes from the satisfaction of the fear and escape motive.

But of all the "instincts", it is the self-assertive or masterful
tendency that comes in oftenest in play. Competition, one form of
self-assertion, is utilized in a tremendous number of games and
sports. Either the players compete {490} as individuals, or they
"choose sides" and compete as teams. No one can deny that the joy of
winning is the high light in the satisfaction of play. Yet it is not
the whole thing, for the game may have been worth while, even if you
lose. Provided you can say, "Though I did not win, I played a good
game", you have the satisfaction of having done well, which is the
mastery satisfaction in its non-competitive form.

When the baby gets a horn, he is not contented to have somebody else
blow it for him, but wants to blow it himself; and very pleased he is
with himself when he can make it speak. "See what _I_ can do!" is the
child's way of expressing his feelings after each fresh advance in the
mastery of his playthings. Great is the joy of the boy when he,
himself, can make his top spin or his kite fly; and great is the
girl's joy when she gets the knack of skipping a rope. Great is any
one's joy when, after his first floundering, he comes to ride a
bicycle, and the sense of power is enhanced in this case by covering
distance easily, and so being master of a larger environment. As boys,
I remember, we used to take great delight in the "apple thrower",
which was simply a flexible stick, sharpened at one end to hold a
green apple. With one's arm thus lengthened, the apple could be thrown
to extraordinary distances, and to see our apple go sailing over a
tall tree or striking the ground in the distance, gave a very
satisfying sense of power. All of those toys that enable you to act at
a distance, or to move rapidly, minister to the mastery impulse.
Imitative play does the same, in that it enables the child to perform,
in make-believe, the important deeds of adults. Children like to play
at being grown-up, whether by wearing long dresses or by smoking, and
it makes them feel important to do what the grown-ups do; you can
observe how important they feel by the way they strut and swagger.

{491}

All in all, there are several different ways of gratifying the
self-assertive or mastery impulse in play: always there is the toy or
game-situation to master and manage; often self-importance is
gratified by doing something big, either really or in make-believe;
and usually there is a competitor to beat.


Empathy

There is still another possible way in which play may gratify the
mastery impulse. Why do we like to see a kite flying? Of course, if it
is _our_ kite and we are flying it, the mastery impulse is directly
aroused and gratified; but we also like to watch a kite flown by some
one else, and similarly we like to watch a hawk, a balloon or
aeroplane, a rocket. We like also to watch things that balance or
float or in other ways seem to be superior to the force of gravity.
Why should such things fascinate us? Perhaps because of _empathy_, the
"feeling oneself into" the object contemplated. As "sympathy" means
"feeling with", "empathy" means "feeling into", and the idea is that
the observer projects himself into the object observed, and gets some
of the satisfaction from watching an object that he would get from
_being_ that object. Would it not be grand to be a kite, would it not
be masterful? Here we stand, slaves of the force of gravity, sometimes
toying with it for a moment when we take a dive or a coast, at other
times having to struggle against it for our very lives, and all the
time bound and limited by it--while the kite soars aloft in apparent
defiance of all such laws and limitations. Of course it fascinates us,
since watching it gives us, by empathy, some of the sense of power and
freedom that seems appropriate to the behavior of a kite. Perhaps the
fascination of fire is empathy of a similar sort; for fire is power.

Having thus found the mastery impulse here, there, and {492} almost
everywhere in the realm of play, we are tempted to assume a masterful
attitude ourselves and say, "Look you! We have discovered the one and
only play motive, which is none other than the instinct of
self-assertion". Thus we should be forgetting the importance in play
of danger and the escape motive, the importance of manipulation for
its own sake, and the importance of the mere joy in muscular and
mental activity. Also, we should be overlooking the occasional
presence of laughter, the occasional presence of sex attraction, and
the almost universal presence of the gregarious and other social
motives. Play gratifies many instincts, not merely a single one.

Further, it is very doubtful whether the whole satisfaction of play
activity can be traced to the instincts, anyway, for play may bring in
the native "likes and dislikes", which we saw [Footnote: See p. 180.]
to be irreducible to instinctive tendencies; and it may bring in
acquired likes and interests developed out of these native likes. Play
gives rise to situations that are interesting and attractive to the
players, though the attraction cannot be traced to any of the
instincts. The rhythm of dancing, marching, and of children's
sing-song games can scarcely be traced to any of the instincts.

The sociability of games goes beyond mere gregariousness, since it
calls for acting together and not simply for being together; and at
the same time it goes beyond competition and self-assertion, as is
seen in the satisfaction the players derive from good team work. It is
true that the individual player does not lay aside his self-assertion
in becoming a loyal member of a team; rather, he identifies himself
with the team, and finds in competition with the opposing team an
outlet for his mastery impulse. But at the same time it is obvious
that self-assertion would be still more fully gratified by man-to-man
contests; and therefore the {493} usual preference of a group of
people for "choosing sides" shows the workings of some other motive
than self-assertion. The fact seems to be that cooerdinated group
activity is an independent source of satisfaction.

If the self-assertive impulse of an individual player is too strongly
aroused, he spoils the game, just as an angry player spoils a friendly
wrestling match or snowball fight, and just as a thoroughly frightened
passenger spoils a trip down the rapids, which was meant to be simply
thrilling. The instincts are active in play, but they must not be too
active, for human play is an activity carried on well above the
instinctive level, and dependent on motives that cannot wholly be
analyzed in terms of the instincts.


Day Dreams

Daydreaming is a sort of play, more distinctly imaginative than most
other play. Simply letting the mind run, as in the instances cited
under free association, where A makes you think of B and B of C, and
so on--this is not exactly daydreaming, since there is no "dream", no
castle in the air nor other construction, but simply a passing from
one recalled fact to another. In imaginative daydreaming, facts are
not simply recalled but are rearranged or built together into a story
or "castle" or scheme. A daydream typically looks toward the future,
as a plan for possible doing; only, it is not a serious plan for the
future--which would be controlled imagination--nor necessarily a plan
which could work in real life, but merely play of imagination. If we
ask the same questions here as we did regarding child's play, we find
again that it is easier to define the end-result and the source of
satisfaction in daydreaming than it is to define the stimulus or the
exact nature of the imaginative process.

{494}

Daydreams have some motive force behind them, as can be judged from
the absorption of the dreamer in his dream, and also from an
examination of the end-results of this kind of imagination. Daydreams
usually have a _hero_ and that hero is usually the dreamer's self.
Sometimes one is the conquering hero, and sometimes the suffering
hero, but in both cases the recognized or unrecognized merit of
oneself is the big fact in the story, so that the mastery motive is
evidently finding satisfaction here as well as in other forms of play.
Probably the conquering hero dream is the commoner and healthier
variety. A classical example is that of the milkmaid who was carrying
on her head a pail of milk she had been given. "I'll sell this milk
for so much, and with the money buy a hen. The hen will lay so many
eggs, worth so much, for which I will buy me a dress and cap. Then the
young men will wish to dance with me, but I shall spurn them all with
a toss of the head." Her dream at this point became so absorbing as to
get hold of the motor system and call out the actual toss of the
head--but we are not after the moral just now; we care simply for the
dream as a very true sample of many, many daydreams. Such dreams are a
means of getting for the moment the satisfaction of some desire,
without the trouble of real execution; and the desire gratified is
very often some variety of self-assertion. Sometimes the hero is not
the dreamer's self, but some one closely identified with himself. The
mother is prone to make her son the hero of daydreams and so to
gratify her pride in him.

The "suffering hero" daydream seems at first thought inexplicable, for
why should any one picture himself as having a bad time, as
misunderstood by his best friends, ill-treated by his family, jilted
by his best girl, unsuccessful in his pet schemes? Why should any one
make believe to be worse off than he is; what satisfaction can that
{495} be to him? Certainly, one would say, the mastery motive could
not be active here. And yet--do we not hear children _boasting_ of
their misfortunes? "Pooh! That's only a little scratch; I've got a
real deep cut." My cut being more important than your scratch makes
me, for the moment, more important than you, and gives me a chance to
boast over you. Older people are known sometimes to magnify their own
ailments, with the apparent aim of enhancing their own importance.
Perhaps the same sort of motive underlies the suffering hero daydream.

I am smarting, let us suppose, from a slight administered by my
friend; my wounded self-assertion demands satisfaction. It was a very
little slight, and I should make myself ridiculous if I showed my
resentment. But in imagination I magnify the injury done me, and go on
to picture a dreadful state of affairs, in which my friend has treated
me very badly indeed, and perhaps deserted me. Then I should not be
ridiculous, but so deeply wronged as to be an important person, one to
be talked about; and thus my demand for importance and recognition is
gratified by my daydream.

Usually the suffering hero pictures himself as in the right, and
animated by the noblest intentions, though misunderstood, and thus
further enhances his self-esteem; but sometimes he takes the other
tack and pictures himself as wicked--but as very, very wicked, a
veritable desperado. It may be his self-esteem has been wounded by
blame for some little meanness or disobedience, and he restores it by
imagining himself a great, big, important sinner instead of a small
and ridiculous one. In adolescence, the individual's growing demand
for independence is often balked by the continued domination of his
elders, and he rebelliously plans quite a career of crime for himself.
He'll show them! They won't be so pig-headedly complacent when they
know they have driven him to the bad. You can tell by the looks of
{496} a person whose feelings are hurt that he is imagining something;
usually he is imagining himself either a martyr or a desperado, or
some other kind of suffering hero, often working up into a conquering
hero in the end, when, his self-esteem restored, he is ready to be
friends again. The suffering hero daydream is a "substitute reaction",
taking the place of a fight or some other active self-assertion. The
conquering hero daydream is often motivated in the same way; for
example, our friend the milkmaid would not have been so ready to scorn
the young men with a toss of the head if she had not been feeling her
own actual inferiority and lack of fine clothes. The daydream makes
good, in one way or another, for actual inability to get what we
desire. The desire which is gratified in the play of imagination
belongs very often indeed under the general head of self-assertion;
but when one is in love it is apt to belong under that head. Love
dreams of the agreeable sort need no further motivation; but the
unpleasant, jealous type of love dream is at the same time a suffering
hero dream, and certainly involves wounded self-assertion along with
the sexual impulse. Probably the self-asserting daydream is the
commonest variety, take mankind as a whole, with the love dream next
in order of frequency. But there are many other sorts. There is the
humor daydream, illustrated by the young person who suddenly breaks
into a laugh and when you ask why replies that she was thinking how
funny it would be if, etc., etc. She is very fond of a good laugh, and
not having anything laughable actually at hand proceeds to imagine
something. So, a music lover may mentally rehearse a piece when he has
no actual music to enjoy; and if he has some power of musical
invention, he may amuse himself, in idle moments, by making up music
in his head; just as one who has some ability in decorative design may
fill his idle moments by concocting new designs on paper. {497} When
vacation time approaches, it is hard for any one, student or
professor, to keep the thoughts from dwelling on the good times ahead,
and getting some advance satisfaction. Thus all kinds of desires are
gratified in imagination.



Worry

Do we have fear daydreams, as we have amusements utilizing the fear
and escape motive? Yes, sometimes we imagine ourselves in danger and
plan out an escape. One individual often amuses himself by imagining
he is arrested and accused of some crime, and figuring out how he
could establish an alibi or otherwise prove his innocence. But fear
daydreams also include _worry_, which seems at first to be an
altogether unpleasant state of mind, forced upon us and not indulged
in as most daydreams are. Yet, as the worry is often entirely
needless, it cannot be said to be forced upon a person, but must have
some motive. There must be some satisfaction in it, in spite of all
appearance.

Some abnormal cases of worry suggest the theory that the fear is but a
cloak for unacknowledged desire. Take this extreme case. A young man,
"tied to the apron-strings" of a too affectionate and too domineering
mother, has a strong desire to break loose and be an independent unit
in the world; but at the same time, being much attached to his mother,
he is horrified by this desire. She goes on a railroad journey without
him--just an ordinary journey with no special danger--but all the time
she is away he is in an agony of suspense lest the train may be
wrecked. Such an abnormal degree of worry calls for explanation.
Well--did not the worry perhaps conceal a wish, a wish that the train
_might_ be wrecked? So he would be set free without any painful effort
on his part; and he {498} was a young man who shrank from all effort.
The psychopathologist who studied the case concluded that this was
really the explanation of the worry.

If, however, we take such extreme cases as typical and cynically apply
this conception to all worries, we shall make many mistakes. A student
worries unnecessarily about an examination; therefore, he desires to
fail. A mother worries because her child is late in getting home;
therefore, she wants to be rid of that child. Thus, by being too
psychopathological, we reach many absurd conclusions in everyday life;
for it is the child that is loved that is worried over, and it is the
examination that the student specially wishes to pass that he fears he
has flunked.

Worry is a sort of substitute reaction, taking the place of real
action when no real action is possible. The student has done all he
can do; he has prepared for the examination, and he has taken the
examination; now there is nothing to do except wait; so that the
rational course would be to dismiss the matter from his mind; if he
cannot accomplish that, but must do something, then the only thing he
can do is to speculate and worry. So also the mother, in her
uncertainty regarding her child, is impelled to action, and if she
knew of any real thing to do she would do it and not worry; but there
is nothing to do, except in imagination. Worry is fundamentally due to
the necessity of doing something with any matter that occupies our
mind; it is an imaginative substitute for real action.

But worry may be something of an indoor sport as well. Consider
this--if the mother really believed her child had fallen into the
pond, she would rush to pull him out; but while she is worrying for
fear he may have fallen in, she remains at home. Really she expects to
see him come home any minute, but by conjuring up imaginary dangers
she is getting ready to make his home-coming a great relief instead
{499} of a mere humdrum matter. She is "shooting the chutes", getting
the thrill of danger with escape fully expected.

The normal time for a daydream is the time when there is no real act
to be performed. A strong man uses it as the amusement of an idle
moment and promptly forgets it. But one who is lacking in force,
especially the personal force needed in dealing with other people, may
take refuge in daydreams as a substitute for real doing. Instead of
hustling for the money he needs he may, like Micawber, charm himself
with imagining the good opportunities that may turn up. Instead of
going and making love to the lady of his choice, he shyly keeps away
from her and merely dreams of winning her. He substitutes imaginary
situations for the real facts of his life, and gratifies his mastery
motive by imaginary exploits. He invents imaginary ailments to excuse
his lack of real deeds. He conjures up imaginary dangers to worry
over. All this is abuse of imagination.


Dreams

Let us turn now from daydreams to dreams of the night. These also are
play of imagination, even freer from control and criticism than the
daydream. In sleep the cortical brain functions sink to a low level,
and perhaps cease altogether in the deepest sleep. Most of the dreams
that are coherent enough to be recalled probably occur just after we
have gone to sleep or just before we wake up, or at other times when
sleep is light. At such times the simpler and more practised
functions, such as recall of images, can go on, though criticism, good
judgment, reasoning, and all that sort of delicate and complex
activity, do not occur. Daytime standards of probability, decorum,
beauty, wit, and excellence of any sort are in abeyance; consistency
is thrown to the winds, the scenes being shifted in the middle of a
{500} speech, and a character who starts in as one person merging
presently into somebody else. Dreams follow the definition of
imagination or invention, in that materials recalled from different
contexts are put together into combinations and rearrangements never
before experienced. The combinations are often bizarre and
incongruous.

Perhaps the most striking characteristic of dreams is their seeming
reality while they last. They seem real in spite of their incongruity,
because of the absence of critical ability during sleep. In waking
life, when the sight of one object reminds me of another and calls up
an image of that other, I know that the image is an image, and I know
I have thought of two different things. In sleep the same recall by
association occurs, but the image is forthwith accepted as real; and
thus things from different sources get together in the same dream
scene, and a character who reminds us of another person forthwith
becomes that other person. We are not mentally active enough in sleep
to hold our images apart. Associative recall, with blending of the
recalled material, and with entire absence of criticism, describes the
process of dreaming.

What is the _stimulus_, to which the dream responds? Sometimes there
is an actual sensory stimulus, like the alarm clock or a stomach ache;
and in this case the dream comes under the definition of an illusion;
it is a false perception, more grotesquely false than most illusions
of the day. A boy wakes up one June morning from a dream of the Day of
Judgement, with the last trump pealing forth and blinding radiance all
about--only to find, when fully awake, that the sun is shining in his
face and the brickyard whistle blowing the hour of four-thirty a.m.
This was a false perception. More often, a dream resembles a daydream
in being a _train of thoughts and images_ without much relation to
present sensory stimuli; and then the dream {501} would come under the
definition of hallucination instead of illusion.

Sometimes a sensory stimulus breaks in upon a dream that is in
progress, and is interpreted in the light of this dream. In one
experiment, the dreamer, who was an authoress, was in the midst of a
dream in which she was discussing vacation plans with a party of
friends, when the experimenter disturbed her by declaiming a poem; in
her dream this took the form of a messenger from her publisher,
reciting something about a contract which seemed a little disturbing
but which she hoped (in the dream) would not interfere with her
vacation. Maury, an early student of this topic, was awakened from a
feverish dream of the French Revolution by something falling on his
neck; this, under the circumstances, he took to be the guillotine.

Now, _why_ is a dream? What satisfaction does it bring to the dreamer?
Or shall we say that it is merely a mechanical play of association,
with no motivation behind it? Dreams are interesting while they last,
sometimes fearful, sometimes angry, sometimes amorous, otherwise not
very emotional but distinctly interesting, so that many people hate to
have a dream broken up by awaking. It seems likely, then, that dreams
are like daydreams in affording gratification to desires. They are
"wish-fulfilling", to borrow a term from Freud's theory of dreams,
soon to be considered.

A boy dreams repeatedly of finding whole barrels of assorted
jackknives, and is bitterly disappointed every time to awake and find
the knives gone; so that finally he questions the reality of the
dream, but pinching himself (in the dream) concludes he must be awake
this time. An adult frequently dreams of finding money, first a nickel
in the dust, and then a quarter close by, and then more and more, till
he wakes up and spoils it all. Such dreams are {502} obviously
wish-fulfilling, as are also the sex dreams of sexually abstinent
persons, or the feasting dreams of starving persons, or the polar
explorer's recurring dream of warm, green fields. An eminent
psychologist has given a good account of a dream which he had while
riding in an overcrowded compartment of a European train, with the
window closed and himself wedged in tightly far from the window. In
this uncomfortable situation he dropped asleep and dreamed that he had
the seat next to the window, had the window open and was looking out
at a beautiful landscape. In all these cases _the wish gratified in
the dream is one that has been left unsatisfied in the daytime_, and
this is according to the famous passage, slightly paraphrased, "What a
man hath, why doth he yet dream about?" The newly married couple do
not dream of each other. We seldom dream of our regular work, unless
for some reason we are disturbed over it. The tendencies that are
satisfied during the day do not demand satisfaction in dreams; but any
tendency that is aroused during the day without being able to reach
its conclusion is likely to come to the surface in a dream.

Any sort of desire or need, left unsatisfied in the day, may motivate
a dream. Desire for food, warmth, sex gratification, air, money, etc.,
have been exemplified in dreams already cited. Curiosity may be the
motive, as in the case of an individual, who, having just come to live
in Boston, was much interested in its topography, and who saw one day
a street car making off in what seemed to him a queer direction, so
that he wondered where it could be going and tried unsuccessfully to
read its sign. The next night he dreamed of seeing the car near at
hand and reading the sign, which, though really consisting of nonsense
names, satisfied his curiosity during the dream.

The mastery motive, so prominent in daydreams, can be detected also in
many sleep dreams. There are dreams in {503} which we do big
things--tell excruciatingly funny jokes, which turn out when recalled
next day to be utterly flat; or improvise the most beautiful music,
which we never can recall with any precision, but which probably
amounted to nothing; or play the best sort of baseball. The gliding or
flying dream, which many people have had, reminds one of the numerous
toys and sports in which defiance of gravity is the motive; and
certainly it gives you a sense of power and freedom to be able, in a
dream, to glide gracefully up a flight of stairs, or step with ease
from the street upon the second-story balcony. One dream which at
first thought cannot be wish-fulfilling perhaps belongs under the
mastery motive: The dreamer sees people scurrying to cover, looks up
and sees a thunderstorm impending; immediately he is struck by
lightning and knocked down in the street; but he finds he can rise and
walk home, and seems to have suffered no harm except for a black
blotch around one eye. Now, any man who could take lightning that way
would be proud to wear the scar. So the dream was wish-fulfilling, and
the wish involved was, as often, the self-assertive impulse.

This last dream is a good one, however, for pointing another moral. We
need not suppose that the dreamer was aiming at the denouement from
the beginning of the dream. Dreams have no plot in most instances;
they just drift along, as one thing suggests another. The sight of
people running to cover suggested a thunderstorm, and that suggested
that "I might get struck", as it would in the daytime. Now, the dream
mentality, being short on criticism, has no firm hold on "may be" and
"might be", but slides directly into the present indicative. The
thought of being struck is _being_ struck, in a dream. So we do not
need to suppose that the dreamer pictured himself as struck by
lightning in order to have the satisfaction of coming off {504} whole
and bragging of the exploit. In large measure the course of a dream is
determined by free association; but the mastery motive and other
easily awakened desires act as a sort of bias, facilitating certain
outcomes and inhibiting others.

But there are unpleasant dreams, as well as pleasant. There are fear
dreams, as well as wish dreams. A child who is afraid of snakes and
constantly on the alert against them when out in the fields during the
day, dreams repeatedly of encountering a mass of snakes and is very
much frightened in his sleep. Another child dreams of wolves or
tigers. A person who has been guilty of an act from which bad
consequences are possible dreams that those consequences are realized.
The officer suffering from nervous war strain, or "shell shock", often
had nightmares in which he was attacked and worsted by the enemy.
Since Freud has never admitted that dreams could be fear-motived,
holding that here, as in worry, the fear is but a cloak for a positive
desire, some of his followers have endeavored to interpret these
shell-shock nightmares as meaning a desire to be killed and so escape
from the strain. To be consistent, they would have also to hold that
the child, who of all people is the most subject to terrifying dreams,
secretly desires death, though not avowing this wish even to himself.
This would be pushing consistency rather far, and it is better to
admit that there are real fear dreams, favored by indigestion or
nervous strain, but sometimes occurring simply by the recall of a
fear-stimulus in the same way that anything is recalled, i.e., through
association.

A large share of dreams does not fit easily into any of the classes
already described. They seem too fantastic to have any personal
meaning. Yet they are interesting to the dreamer, and they would be
worth going to see if they could be reproduced and put on the stage.
Isn't that sufficient {505} excuse for them? May they not be simply a
free play of imagination that gives interesting results because of its
very freedom from any control or tendency, and because of the
vividness of dream imagery?


Freud's Theory of Dreams

Just at this point we part company with Freud, whose ideas on dreams
as wish-fulfilments we have been following, in the main. Not that
Freud would OK our account of dreams up to this point. Far from it. It
would seem to him on too superficial a level altogether, dealing as it
does with conscious wishes and with straightforward fulfilments. It
has left out of account the "Unconscious" and its symbolisms. The
Freudian would shake his head at our interpretation of the lightning
dream, and say, "Oh, there is a good deal more in that dream. We
should have to analyze that dream, by letting the dreamer dwell on
each item of it and asking himself what of real personal significance
the stroke of lightning or the scar around the eye suggested to him.
He would never be able by his unaided efforts to find the unconscious
wishes fulfilled in the dream, but under the guidance of the
psychoanalyst, who is a specialist in all matters pertaining to the
Unconscious, he may be brought to realize that his dream is the
symbolic expression of wishes that are unconscious because they have
been suppressed".

The Unconscious, according to Freud, consists of forbidden
wishes--wishes forbidden by the "Censor", which represents the moral
and social standards of the individual and his critical judgment
generally. When the Censor suppresses a wish, it does not peaceably
leave the system but sinks to an unconscious state in which it is
still active and liable to make itself felt in ways that get by the
Censor because they are disguised and symbolic. An abnormal worry
{506} is such a disguise, a queer idea that haunts the nervous person
is another, "hysterical" paralysis or blindness is another.

In normal individuals the dream life is held by Freud to be the chief
outlet for the suppressed wishes; for then the Censor sleeps and "the
mice can play". Even so, they dare not show themselves in their true
shape and color, but disguise themselves in innocent-appearing
symbolism. That lightning may stand for something much more personal.
Let your mind play about that "being knocked down by lightning and
getting up again", and ask yourself what experience of childhood it
calls up.--Well, I remember the last time my father whipped me and I
came through defiant, without breaking down as I always had before on
similar occasions.--Yes, now we are on the track of something. The
lightning symbolizes your father and his authority over you, which as
a child you resented. You were specially resentful at your father's
hold on your mother, whom you regarded as yours, your father being a
rival with an unfair advantage. Your sex impulse was directed towards
your mother, when you were a mere baby, but you soon came to see (how,
Freud has never clearly explained) that this was forbidden, and that
your father stood in the way. You resented this, you hated your
father, while at the same time you may have loved him, too; so this
whole complex and troublesome business was suppressed to the
Unconscious, whence it bobs up every night in disguise. You may dream
of the death of some one, and on analysis that some one is found to
represent your father, whom as a child you secretly wished out of the
way; or that some one may stand for your younger brother, against whom
you, had a standing grudge because he had usurped your place as the
pet of the family. These childish wishes are the core of the
Unconscious and help to motivate all dreams, but more recently
suppressed {507} wishes may also be gratified in dream symbolism. A
man may "covet his neighbor's wife", but this is forbidden, unworthy,
and false to the neighbor who is also his friend. The wish is
disavowed, suppressed, not allowed in the waking consciousness; but it
gratifies itself symbolically in a dream; the neighbor's wife not
appearing at all in the dream, but the neighbor's automobile instead,
which the neighbor cannot run properly, while the dreamer manages it
beautifully.

Freud has claimed the dream as his special booty, and insists that all
dreams are wish-fulfilments, even those that seem mere fantastic play
of imagination, since, as he sees it, no mental activity could occur
except to gratify some wish. Further, he holds, most if not all dreams
are fulfilments of suppressed wishes, and these are either sex or
spite wishes, the spite wishes growing out of the interference of
other people with our sex wishes.

The objection to Freud's theory of dreams is, first, that he fails to
see how easy-running the association or recall mechanism is. It isn't
necessary to look for big, mysterious driving forces, when we know
that A makes you think of B, and B of C, with the greatest ease. The
dreamer isn't laboring, he is idly playing, and his images come
largely by free association, with personal desires giving some steer.

Another objection is that Freud overdoes the Unconscious; suppressed
wishes are usually not so unconscious as he describes them; they are
unavowed, unnamed, unanalyzed, but conscious for all that. It is not
so much the unconscious wish that finds outlet in dreams and
daydreams, as the unsatisfied wish, which may be perfectly conscious.

Another very serious objection to Freud is that he overdoes the sex
motive or "libido". He says there are two main tendencies, that of
self-preservation and that of reproduction, but that the former is
ordinarily not much subject to suppression, while the latter is very
much under the {508} social ban. Consequently the Unconscious consists
mostly of suppressed sex wishes. Evidently, however, Freud's analysis
of human motives is very incomplete. He does not clearly recognize the
self-assertive tendency, which, as a matter of fact, is subjected to
much suppression from early childhood all through life, and which
undoubtedly has as much to do with dreams, as it has with daydreams.
Freud has given an "impressionistic" picture, very stimulating and
provocative of further exploration, but by no means to be accepted as
a true and complete map of the region.


Autistic Thinking

Dreaming, whether awake or asleep, is free imagination. It does not
have to check up with any standard. So long as it is interesting at
the moment and gratifies the dreamer in any way, it serves its
purpose. Sometimes the daydreamer exercises some control, breaking off
a spiteful or amorous dream because he thinks it had better not be
indulged; but in this he ceases to be simply a daydreamer.
Daydreaming, by itself, is an example of what is called "autistic
thinking", which means thinking that is sufficient unto itself, and
not subjected to any criticism. Autistic thinking gratifies some
desire and that is enough for it. It does not submit to criticism from
other persons nor from other tendencies of the individual, nor does it
seek to square itself with the real world.

Autistic thinking, indulged in by every imaginative person in moments
of relaxation, is carried to an absurd extreme by some types of insane
individuals. One type withdraws so completely from reality as to be
inaccessible in the way of conversation, unresponsive to anything that
happens, entirely immersed in inner imaginings. Others, while living
in the world about them, transform it into a make-believe {509} world
by attaching meanings to things and persons as suits themselves. This
institution, in which the subject is confined, is his royal palace,
the doctors are his officials, the nurses his wives, "thousands of
them, the most beautiful women in creation". Or the delusion may take
the line of the "suffering hero", the subject imagining himself a
great man shut up in this place by the machinations of his enemies;
the doctors are spies and enemy agents, and the nurses also act
suspiciously; his food is poisoned, and he is kept in a weak and
helpless condition, all out of fear of him. It is impossible to argue
the patient out of his delusions by pointing out to him how clearly
they conflict with reality; he evades any such test by some
counter-argument, no matter how flimsy, and sticks to his dream or
make-believe.

Autistic thinking is contrasted with realistic thinking, which seeks
to check up with real facts; it may be contrasted also with socialized
thinking, which submits to the criticism of other people; and it may
even be contrasted with self-criticized thinking, in which the
individual scrutinizes what he has imagined, to see whether it is on
the whole satisfactory to himself, or whether it simply gratified a
single or momentary impulse that should be balanced off by other
tendencies.


Invention and Criticism

"Criticism"--the word has been used repeatedly, and it is time it gave
an account of itself. Criticism evidently demands balancing off one
desire by another. One tendency gets criticized by running afoul of
another tendency, one idea by conflicting with another idea. We
concoct a fine joke to play on our friend; but then the thought comes
to us that he may not take it kindly; we don't want to break with our
friend, and so we regretfully throw our promising invention on the
scrap heap. That is self-criticism, the {510} balancing off of one
impulse by another. Self-criticism is obnoxious to the natural man,
who prefers to follow out any tendency that has been aroused till it
reaches its goal; but he learns self-criticism in the hard school of
experience. For plenty of criticism is directed upon the individual
from without.

Criticism is directed upon him by the facts of the real world, so soon
as he tries to act out what he has imagined. Often his invention will
not work, his plan does not succeed, and he is involved in chagrin and
even pain. He must perforce cast away his plan and think up a new one.
At this point the "weak brother" is tempted to give up trying, and
take refuge in autistic thinking, but the stronger individual accepts
the challenge of reality. He sees that an invention is not
satisfactory unless it will really work, and sets about learning what
will work and what not, so accumulating observations that later enable
him to criticize his own ideas, to some extent, before trying them out
on real things.

Criticism is directed upon the individual from the side of other
people, who from the day he first begins to tell his childish
imaginings, are quite free with their objections. Humiliated by this
critical reception of his ideas, the individual may resolve to keep
them to himself for the future, and draw away, again, towards autistic
thinking; or, more forcefully, he may exert himself to find some idea
that will command the approval of other people. If he can take rebuffs
goodnaturedly, he soon finds that social criticism can be a great
help, that two heads are better than one in planning any invention
that needs to work. He accumulates knowledge of what will pass muster
when presented to other people, and thus again learns self-criticism.

Self-criticism is helped by such rules as to "think twice", to "sleep
on it before deciding", to "drop the matter for a time and come back
to it and see whether it still looks {511} the same". When you are all
warmed up over an idea, its recency value gives it such an advantage
over opposing ideas that they have no chance, for the moment, of
making themselves felt in the line of criticism.

I once heard the great psychologist, and great writer, William James,
make a remark that threw some light on his mode of writing. In the
evening, he said, after warming up to his subject, he would write on
and on till he had exhausted the lead he was following, and lay the
paper aside with the feeling, "Good! Good! That's good". The next
morning, he said, it might not seem good at all. This calls to mind
the old advice to writers about its being "better to compose with fury
and correct with phlegm than to compose with phlegm and correct with
fury". The phlegmatic critical attitude interferes considerably with
the enthusiastic inventive activity. Give invention free rein for the
time being, and come around with criticism later.

Some over-cautious and too self-critical persons, though rather
fertile in ideas, never accomplish much in the way of invention
because they cannot let themselves go. Criticism is always at their
elbow, suggesting doubts and alternatives and preventing progress in
the creative activity, instead of biding its time and coming in to
inspect the completed result. For a similar reason, much of the best
inventive work--writing, for example, or painting--is done in
prolonged periods of intense activity, which allow time for invention
to get warmed to its task, when it takes the bit in its teeth and
dashes off at a furious speed, leaving criticism to trail along
behind.

Invention in the service of art or of economic and social needs is
controlled imagination, realistic, socialized, subjected to criticism.
It cannot afford to be autistic, but must meet objective or social
standards. Mechanical inventions must work when translated into
matter-of-fact wood and iron, and {512} must also pass the social test
of being of some use. Social inventions of the order of institutions,
laws, political platforms and slogans, plans of campaign, must "work"
in the sense of bringing the desired response from the public. Social
imagination of the very important sort suggested by the proverbs,
"Seeing ourselves as others see us", or "Putting ourselves in the
other fellow's place"--for it is only by imagination that we can thus
get outside of our own experience and assume another point of
view--must check up with the real sentiments of other people.


The Enjoyment of Imaginative Art

It requires imagination to enjoy art as well as to produce it. The
producer of the work of art puts the stimuli before you, but you must
make the response yourself, and it is an inventive response, not a
mere repetition of some response you have often made. The novelist
describes a character for you, and you must respond by putting
together the items in the description so as to conceive of a character
you have never met. The painter groups his figures before you, but you
must get the point of the picture for yourself. The musical composer
provides a series of chords, but you must get the "hang" of the
passage for yourself, and if he has introduced a novel effect, it may
not be easy to find any beauty in it, at least on the first hearing.

Art, from the consumer's side, is play. It is play of the imagination,
with the materials conveniently presented by the artist. Now, as art
is intended to appeal to a consumer (or enjoyer), the question as to
sources of satisfaction in the enjoyment of art is fundamental in the
whole psychology of art, production as well as consumption.

We have the same questions to ask regarding the enjoyment of a _novel_
as regarding a daydream. Novel-reading is daydreaming with the
materials provided by the {513} author, and gratifies the same
motives. A novel to be really popular must have a genuine hero or
heroine--some one with whom the reader can identify himself. The
frequency of novels in which the hero or heroine is a person of high
rank, or wins rank or wealth in the course of the story, is a sign of
appeal to the mastery motive. The humble reader is tickled in his own
self-esteem by identifying himself for the time with the highborn or
noble or beautiful character in the story. The escape motive also is
relied upon to furnish the excitement of the story, which always
brings the hero into danger or difficulty and finally rescues him,
much to the reader's relief. Love stories appeal, of course, to the
sex impulse, humorous stories to laughter, and mystery stories to
curiosity. Cynical stories, showing the "pillars of society" in an
ignoble light, appeal to the self-assertive impulse of the reader, in
that he is led to apply their teaching to pretentious people whom he
knows about, and set them down a peg, to his own relative advancement.
But here again we have to insist, as under the head of sports and
daydreams, that interests of a more objective kind are also gratified
by a good work of fiction. A story that runs its logical course to a
tragic end is interesting as a good piece of workmanship, and as an
insight into the world. We cannot heartily identify ourselves with
Hamlet or Othello, yet we should be sorry to have those figures erased
from our memories; they mean something, they epitomize world-facts
that compel our attention.


The appeal of art is partly emotional.

A very great work of art, the Apollo Belvedere or the Sistine Madonna,
when you suddenly come upon it in walking through a gallery, may move
you almost or quite to tears. Beautiful music, and not necessarily sad
music either, has the same effect. Why this particular emotion should
be aroused is certainly an enigma. "Crying because you are so happy"
is similar {514} but itself rather inexplicable. In many other cases,
the emotional appeal of art is easily analyzed. The pathetic appeals
straightforwardly to the grief impulse, the humorous to the laughter
impulse, the tragic to fear and escape. The sex motive is frequently
utilized in painting and sculpture as well as in literature.


Art makes also an intellectual appeal.

It is satisfying partly because of this appeal, as is clear when we
remember that many great works of art require mental effort in order
to grasp and appreciate them. You must be wide-awake to follow a play
of Shakespeare; you must puzzle out the meaning of a group painting
before fully enjoying it; you must study some of the detail of a
Gothic cathedral before getting the full effect; music may be too
"classical" for many to grasp and follow. Unless, then, the artist has
made a great mistake, the mental activity which he demands from his
public must contribute to the satisfaction they derive from his works.
If his appeal were simply to their emotions, any intellectual labor
would be a disturbing element. The intellectual appeal is partly to
objective interests in the thing presented, partly to interest in the
workmanship, and partly to the mastery motive in the form of problem
solution.

Perhaps we do not often think of a fine painting or piece of music as
a problem set us for solution, but it is that, and owes part of its
appeal to its being a problem. To "get the hang of" a work of art
requires some effort and attention; if the problem presented is too
difficult for us, the work of art is dry; if too easy, it is tame.

The mastery motive is probably as important in the enjoyment of art as
it is in play and dreaming. It comes in once in the joy of mastering
the significance of the work of art, and again in self-identification
with the fine characters portrayed.

{515}

Empathy in art enjoyment.

At first thought, some forms of art, as architecture, seem incapable
of making the just-mentioned double appeal to the mastery motive.
Architecture can certainly present problems for the beholder to solve,
but how can the beholder possibly identify himself with a tower or
arch? If, however, we remember the "empathy" that we spoke of under
the head of play, we see that the beholder may project himself into
the object, unintentionally of course, and thus perhaps get
satisfaction of his mastery impulse.

Look at a pillar, for example. If the pillar is too massive for the
load supported, it gives you the unsatisfactory impression of doing
something absurdly small for your powers. If on the contrary the
pillar is too slender for the load that seems to rest upon it, you get
the feeling of strain and insecurity; but if it is rightly
proportioned, you get the feeling of a worthy task successfully
accomplished. The pillar, according to empathy, pleases you by
arousing and gratifying your mastery impulse; and many other
architectural effects can be interpreted in the same way.

Empathy can perhaps explain the appeal of the _big_ in art and nature.
In spite of the warnings put forth against thinking of mere bigness as
great or fine, we must admit that size makes a very strong appeal to
something in human nature. The most perfect miniature model of a
cathedral, however interesting and attractive as it rests on the table
before you, fails to make anything like the impression that is made by
the giant building towering above you. Big trees, lofty cliffs, grand
canyons, tremendous waterfalls, huge banks of clouds, the illimitable
expanse of the sea, demonstrate cogently the strong appeal of the big.
Perhaps the big is not necessarily grand, but the grand or sublime
must be big or somehow suggest bigness. The question is, then, what it
is in us that responds to the appeal of the big.

{516}

Perhaps it is the submissive tendency that is aroused. This great
mountain, so far outclassing me that I am not tempted in the least to
compete with it, affords me the joy of willing submission. The escape
motive may come in along with submissiveness--at the first sight of
the mountain a thrill of fear passes over me, but I soon realize that
the mountain will not hurt me in spite of its awe-inspiring vastness;
so that my emotion is blended of the thrill of fear, the relief of
escape, and the humble joy of submission. That is one analysis of the
esthetic effect of bigness.

Empathy suggests a very different analysis. According to this,
projecting myself into the mountain, identifying myself with it, I
experience the sensation of how it feels to be a mountain. It feels
big--I feel big. My mastery impulse is gratified. To decide between
these two opposing interpretations ought to be possible from the
behavior or introspection of a person in the presence of some big
object. If he feels insignificant and humble and bows reverently
before the object, we may conclude that the submissive tendency is in
action; but if the sight of the grand object makes him feel strong and
fine, if he throws out his chest and a gleam comes into his eye, then
everything looks like the mastery motive. Quite possibly, the effect
varies with the person and the occasion.

We have to think of art as a great system or collection of inventions
that owes its existence to its appeal to human nature, and that has
found ways, as its history has progressed, of making its appeal more
and more varied. Art is a type in these respects of many social
enterprises, such as sport, amusement, and even such serious matters
as politics and industry. Each of these is a collection of inventions
that persists because it appeals to human impulses, and each one
appeals to a variety of different impulses.


{517}

The Psychology of Inventive Production

To the consumer, art is play, but to the producer it is work, in the
sense that it is directed towards definite ends and has to stand
criticism according as it does or does not reach those ends. What is
true of the producer of art works is true also of other inventors, and
we may as well consider all sorts of controlled imagination together.

In spite of the element of control that is present in productive
invention, the really gifted inventor seems to make play of his work
to a large extent. Certainly the inventive genius does not always have
his eyes fixed on the financial goal, nor on the appeal which his
inventions are to make to the public. It is astonishing to read in the
lives of inventors what a lot of comparatively useless contrivances
they busied themselves with, apparently from the pure joy of
inventing. One prolific writer said that he "never worked in his life,
only played". The inventor likes to manipulate his materials, and this
playfulness has something to do with his originality, by helping to
keep him out of the rut.

That "necessity is the mother of invention" is only half of the truth;
it points to the importance of a directive tendency, but fails to show
how the inventor manages to leave the beaten path and really invent.
Necessity, or some desire, puts a question, without which the inventor
would not be likely to find the answer; but he needs a kind of
flexibility or playfulness, just because his job is that of seeing
things in a new light. We must allow him to toy with his materials a
bit, and even to be a bit "temperamental", and not expect him to grind
out works of art or other inventions as columns of figures are added.

When inventive geniuses have been requested to indicate their method,
they have been able to give only vague hints. How does the musical
composer, for example, free himself of {518} all the familiar pieces
and bring the notes into a fresh arrangement? All that he can tell
about it is usually that he had an "inspiration"; the new air simply
came to him. Now, of course the air did not really come to him from
outside; he made it, it was his reaction, but it was a quick, free
reaction, of which he could observe little introspectively.

Perhaps the best-studied case of invention is that of the learner in
typewriting, who, after laboriously perfecting his "letter habits" or
responses to single letters by appropriate finger movements on the
keyboard, may suddenly find himself writing in a new way, the word no
longer being spelled out, but being written as a unit by a cooerdinated
series of finger movements. The amazing thing is that, without trying
for anything of the kind, he has been able to break away from his
habit of spelling out the word, and shift suddenly to a new manner of
writing. He testifies that he did not plan out this change, but was
surprised to find himself writing in the new way. He was feeling well
that day, hopeful and ambitious, he was striving for greater speed,
and, while he was completely absorbed in his writing, this new mode of
reaction originated.

We see in this experimentally studied case some of the conditions that
favor invention. Good physical condition, freshness, mastery of the
subject, striving for some result, and "hopefulness". Now, what is
that last? Confidence, enterprise, willingness to "take a chance",
eagerness for action and readiness to break away from routine? Some of
this independent, manipulating spirit was probably there.

A soldier, so wounded as to paralyze his legs but capable of recovery
by training, had advanced far enough to hobble about with a cane and
by holding to the walls. One morning, feeling pretty chipper, he took
a chance and left the wall, cutting straight across the room; and
getting through without a fall, was naturally much encouraged and
{519} maintained this advance. This might be called invention; it was
breaking away from what had become routine, and that is the essential
fact about the inventive reaction. This playful spirit of cutting
loose, manipulating, and rearranging things to suit yourself is
certainly a condition favorable to invention. It does not guarantee a
valuable invention, but it at least helps towards whatever invention
the individual's other qualifications make possible.

Another condition favorable to invention is youth. Seldom does a very
old person get outside the limits of his previous habits. Few great
inventions, artistic or practical, have emanated from really old
persons, and comparatively few even from the middle-aged. On the other
hand, boys and girls under eighteen seldom produce anything of great
value, not having as yet acquired the necessary mastery of the
materials with which they have to deal. The period from twenty years
up to forty seems to be the most favorable for inventiveness.


Imagination Considered in General

Finally, we must return to the question of definition or general
description that was left open near the beginning of the chapter.
There seem to be two steps in the inventive response, one preliminary,
the other strictly inventive. The preliminary step brings the stimuli
to bear, and invention is the response that follows.

Typically, the preliminary stage consists in recall; and association
by similarity, bringing together materials from different past
experiences, is very important as a preliminary to invention. Facts
recalled from different contexts are thus brought together, and
invention consists in a response to such novel combinations of facts.
The two steps in invention are, first, getting a combination of
stimuli, and second, responding to the combination.

{520}

Sometimes it has been said that imagination consists in putting
together material from different sources, but this leaves the matter
in mid-air; recall can bring together facts from different sources and
so afford the stimulus for an imaginative response, but the response
goes beyond the mere togetherness of the stimuli. Thinking of a man
and also of a horse is not inventing a centaur; there is a big jump
from the juxtaposition of the data to the specific arrangement that
imagination gives them. The man plus the horse may give no response at
all, or may give many other responses besides that of a centaur; for
example, a picture of the man and the horse politely bowing to each
other. The particular manipulation, or imaginative response, that is
made varies widely; sometimes it consists in taking things apart
rather than putting them together, as when you imagine how a house
would look with the evergreen tree beside it cut down; always it
consists in putting the data into new relationships.

Imagination thus presents a close parallel to reasoning, where, also,
there are two stages, the preliminary consisting in getting the
premises together and the final consisting in perceiving the
conclusion. The final response in imagination is in general like that
in reasoning; both are _perceptive reactions_; but imagination is
freer and more variable. Reasoning is governed by a very precise aim,
to see the actual meaning of the combined premises; that is, it is
exploratory; while imagination, though it is usually more or less
steered either by a definite aim or by some bias in the direction of
agreeable results, has after all much more latitude. It is seeking,
not a relationship that is there, but one that can be put there.

{521}

EXERCISES

1. Outline the chapter.

2. Make a list of hobbies and amusements that you specially enjoy,
   and try to discover the sources of satisfaction in each.

3. Recall two stories that you specially enjoyed, and try to
   discover the sources of satisfaction in each.

4. How far does the account of daydreams given in the text square
   with your own daydreams, and how far does it seem inadequate?

5. An experiment on the speed of revery or of daydreaming.
   Beginning at a recorded time, by your watch, let your mind wander
   freely for a few moments, stopping as soon as your stream of
   thoughts runs dry. Note the time at the close. Now review your
   daydream (or revery), and tally off the several scenes or
   happenings that you thought of, so as to count up and see how many
   distinct thoughts passed through your mind. How many seconds, on
   the average, were occupied by each successive item?

6. Why do dreams seem real at the time?

7. Analysis of a dream. Take some dream that you recall well, and let
   your thoughts play about it, and about the separate items of
   it--about each object, person, speech, and happening in the
   dream--with the object of seeing whether they remind you of
   anything personally significant. Push the analysis back to your
   childhood, by asking whether anything about the dream symbolizes
   your childish experiences or wishes. To be sure, the psychoanalyst
   would object that the individual cannot be trusted to make a
   complete analysis of his own dream--just as the psychologist would
   object to your accepting the recalled experiences and wishes as
   necessarily standing in any causal relation to your dream--but, at
   any rate, the exercise is interesting.

8. Problems in invention. Solve some of these, and compare the
   mental process with that of reasoning.

  (a) Devise a game to be played by children and adults together,
      to everybody's satisfaction.

  (b) Imagine a weird animal, after the analogy of the centaur.

  (c) Imagine an interesting incident, bringing in an old man,
      a little girl, and a waterfall.

  (d) Design the street plan for an ideal small town, built on
      both sides of a small river.

9. Show how empathy might make us prefer a symmetrical building to
   one that is lop-sided.


{522}


REFERENCES


On the imagination and play of children, see Norsworthy and Whitley's
_Psychology of Childhood_, 1918, Chapters IX and XII.

For Freud's views regarding dreams, see his _Interpretation of
Dreams_, translated by Brill, 1913.

For a view which, though psychoanalytical, diverges somewhat from that
of Freud, see Maurice Nicoll, _Dream Psychology_, 1917; also C. W.
Kimmins, _Children's Dreams_, 1920.

For studies of play, see Edward S. Robinson, "The Compensatory
Function of Make-Believe Play", in the _Psychological Review_ for
1920, Vol. 27, pp. 429-439; also M. J. Reaney, _The Psychology of the
Organized Group Game_, 1916.

On invention, see Josiah Royce, "The Psychology of Invention", in the
_Psychological Review_ for 1898, Vol. 5, pp. 113-144; also F. W.
Taussig's _Inventors and Money-Makers_, 1915.


{523}

CHAPTER XX

WILL

PLANNED ACTION, ACTION IN SPITE OF INTERNAL CONFLICT,
AND ACTION AGAINST EXTERNAL OBSTRUCTION


If the psychologist were required to begin his chapter on the will
with a clean-cut definition, he would be puzzled what to say. He might
refer to the old division of the mind into the "three great faculties"
of intellect, feeling, and will, but would be in duty bound to add at
once that this "tripartite division" is now regarded as rather
useless, if not misleading. It is misleading if it leads us to
associate will exclusively with motor action, for we also have
voluntary attention and voluntary control in reasoning and inventing,
and we have involuntary motor reactions. "Will" seems not to be any
special kind of response, but rather to refer to certain relationships
in which a response may stand to other responses--but this is
certainly too vague a definition to be of use.

"Will" is not precisely a psychological term, anyway, but is a term of
common speech which need not refer to any psychological unit. In
common speech it has various and conflicting meanings. "Since you urge
me", one may say, "I _will_ do this, though much against my _will_."
Let the dictionary define such words. What psychology should do with
them is simply to take them as a mining prospector takes an
outcropping of ore: as an indication that it may pay to dig in the
neighborhood.

{524}

Voluntary and Involuntary Action

About the first thing we strike when we start digging is the
distinction between voluntary and involuntary. A man has committed
homicide, and the question in court is whether he did it "with malice
aforethought", i.e., with full will and intention, whether he did it
in a sudden fit of anger, i.e., impulsively rather than quite
voluntarily, or whether it was an accident and so wholly unintentional
or involuntary. The court wishes to know, since a man who has
committed one sort of homicide is a very different character from one
who has committed another sort; different acts can be expected from
him in the future and different precautions need to be taken
accordingly.

It is a fact, then, that an act may be performed either with or
without foreknowledge--a remarkable fact both ways! An intentional act
is remarkable from the side of physics or chemistry or botany--which
is to say that it is very exceptional in nature at large. On the other
hand, a completely involuntary act is rather exceptional in human
behavior and perhaps in animal behavior as well, for almost always
there is some striving towards an end, some impulse. The simplest
reflexes, to be sure, are completely involuntary. The pupillary
reaction to light is not done with malice aforethought, cannot be so
done. The lid reflex, or wink of the eye, occurs many times in the
course of an hour, without foreknowledge, or after-knowledge for that
matter, though the same movement can be made voluntarily. Sneezing and
coughing are not voluntary in the full sense, but they are distinctly
impulsive, they strive towards desired relief. To sneeze voluntarily
is to sneeze when you don't want to, and to sneeze involuntarily is to
sneeze when you want to--which seems queer, since we usually think of
a voluntary act as one done to further our wishes. The solution of
this puzzle is, {525} of course, that a voluntary sneeze is desired
not because of a direct impulse but to gain some ulterior end, such as
to prove we can do it, or for histrionic purposes--in short, for some
purpose beyond the immediate satisfaction of an impulse.

Thus we may classify acts as wholly involuntary or mechanical, as
impulsive, and as distinctly voluntary or purposive. Or, we may
arrange acts in a scale from those that have no conscious end, through
those aimed directly at an immediate end, up to those done to
accomplish an ulterior end which is imagined beforehand. The last
class of fully voluntary acts belongs under the general head of
manipulation, just as imagination does. We _imagine some change_ to be
produced in the existing situation and then proceed to put our
imagination into effect; and this is a typical voluntary act.

We seldom, however, picture a _complete_ act in imagination before
executing it. Even so simple an act as closing the fist cannot be
completely pictured beforehand; for if you try to imagine how the
closed fist is going to feel and then close it, you will find that you
left out of your image many details of the actual kinesthetic
sensations. What we imagine and intend is _some_ change in the
situation, and we then proceed to execute that change and other
changes incidentally.

Besides the simple reflexes, there is another sort of involuntary and
mechanical action. Through practice and repetition, an act may become
so habitual as to be done automatically, that is, without being
imagined beforehand, and even without conscious impulse. The practised
typist responds in this way to the words he is copying. We should
notice, however, that this does not mean that the total behavior and
state of mind of the typist is mechanical and devoid of impulse. The
typist may write the letters {526} mechanically, and if expert may
write even words in this way, but all the time he is consciously
aiming to copy the passage. His attention and impulse have deserted
the fully mastered details and attach themselves to the larger units.
In the same way, in signing your name you have no conscious intention
or impulse to write each successive letter; but you fully intend to
sign your name.


Development of Voluntary Control

The child's actions are at first impulsive but not voluntary in the
full sense, since obviously he cannot imagine and intend an act till
he has had experience of that act, and he must usually have
experienced doing the act himself before he can effectively imagine
it. At least, this is true of the simpler movements; compound
movements, made up of familiar elements, may be first observed in
other persons and then voluntarily imitated. The child's process of
acquiring voluntary control over a movement is illustrated by the
story of how the baby learned to put his hand in his mouth. He first
made this movement in the course of "aimless" throwing of his arms
about, liked the sensation of the hand in the mouth, tried apparently
to get it there again, and in the course of a few days was able to put
it there at will. The child's "aimless" movements at the start were
probably impulsive, but they were not directed towards any
preconceived end. Then, having observed a desirable result of one
movement, he worked towards that result by trial and error, till
finally he had the necessary movement so closely linked to the thought
of the result as to follow directly upon the thought.

Once brought under voluntary control, a movement becomes with further
repetition habitual and mechanical, and no longer voluntary or even
impulsive. Thus the voluntary {527} performance of an act intervenes
between the native or instinctive doing of it and the later habitual
doing of it. Blowing out a match affords another example of this
course of events. A child can of course blow out, instinctively, when
he has the natural stimulus for strong expiration, but he cannot at
will blow at the lighted match. Being prompted and shown, he comes by
degrees to be able to blow out the match; during the learning stage he
has to try, and the act is voluntary; but with further practice it
becomes involuntary, though it may still be executed as part of a
larger voluntary act, such as preventing a burning match from setting
fire to something on which it has fallen.

A complex act, or series of movements, may be voluntary as a whole,
being directed towards some preconceived result, while the single
movements that constitute the series are mechanical, their particular
results no longer being thought of separately. This is well
illustrated by the instances of typewriting, speaking, and signing the
name, mentioned a moment ago. With practice, the interest in a
performance goes more and more to the final result and deserts the
elements of the act.

It is during the organization of reactions that they require attention
and must be thought of before being executed. Organization goes on and
on, a thoroughly organized reaction being later combined with others
into a still bigger act. New demands constantly made upon the
individual prevent him, however well organized, from ever reaching the
condition of a wholly automatic machine. Will, in the sense of action
aimed at the accomplishment of foreseen results, stays with him to the
end.


Ideomotor Action

Involuntary movement is not always "sensorimotor", which means
directly aroused by a sensory stimulus; oftener {528} it is
"ideomotor", or directly aroused by an idea or thought. It may be so
aroused and still be involuntary. We think of a certain result and our
muscles produce this result, though we did not really mean to do this
act ourselves. The thought arouses the movement because it has
previously been linked with the movement. A thought which has
previously served as the stimulus to an act will tend to have this
effect again, unless inhibited by some contrary stimulus. There is no
need of a definite _consent_ to the act, provided there is nothing
present to inhibit it.

Good examples of ideomotor action can be observed among the audience
at an athletic contest. You are watching one of your team do the pole
vault, for instance, and are so much absorbed in his performance and
so desirous for him to succeed that you identify yourself with him to
a degree. He is rising to clear the high bar, and the thought of his
clearing it, monopolizing your mind and leaving no room for the
inhibitory thought that the performer is down there in the field and
you up here in the stand, causes you to make an incipient leg movement
as if you yourself were vaulting.

Voluntary action, in the fullest sense, occurs when you realize the
situation and are definitely conscious of yourself, that is to say,
when you differentiate yourself clearly out of the total situation,
and not only imagine some change to be made, but think of that change
as to be produced _by you_, without at the same time having any
contrary thought to inhibit actual execution.


Conflict and Decision

It appears that in our "digging" we have now struck another vein, for
here we have the fact of one tendency running contrary to another and
inhibiting it. Conflict of desires and the consequent necessity of
_choosing_ between {529} them, is thus brought vividly to our
attention. Every one would at once agree that "will" and "choice"
belong closely together. The most distinctly voluntary acts occur when
two alternatives are thought of, and one of them is chosen.

Organized as we are by nature, that is to say, on a large scale, but
incompletely--environed as we are, with multitudinous stimuli
constantly playing on us and arousing contrary tendencies--we cannot
hope to escape conflict of motives and the necessity of making
decisions. Every decision made, every conflict resolved, is a step in
the further organization of the individual. It may be a step in a good
direction, or in a bad direction, but it is a step in organizing the
individual's reaction-tendencies into what we call his
_character_--the more or less organized sum total of his native and
acquired tendencies to reaction, with emphasis on those reactions that
affect his life and social relations in a broad way.

The lowest animals, having few reaction tendencies, and being
responsive to only a narrow environment, show little sign of internal
conflict, and when it does occur it is resolved very simply by the
advantage going to one of the opposing tendencies, with perhaps a
shift later to the other, in the way described in our earlier
consideration of attention. [Footnote: See p. 251.] This type of
decision is fundamental. In the behavior of higher animals, we
sometimes detect signs of a longer-persisting conflict, as between
curiosity and fear, when a wild creature seems poised between his
inclination to approach and examine a strange object and his
inclination to run away, veering now towards the one and now towards
the other alternative, and unable, as it seems, to reach a decision.

Conflict between the enterprising tendency to explore, manipulate or
somehow launch forth into the new, and the negative tendencies of
fear, inertia, shyness, etc., is {530} something that recurs again and
again in human experience, as illustrated by making up your mind to
get up in the morning, or to plunge into the cold water, or to speak
up and have your say in a general conversation. There is a _hesitancy_
in such cases, due to a positive and a negative tendency. The conflict
may be resolved in favor of the negative tendency by simple
prolongation of the hesitation till the occasion for action has
passed, or it may be resolved in favor of the positive tendency when
this is strong enough for an instant to enable the individual to
commit himself to the enterprise, after which he usually stays
committed. The positive motive must for an instant be stronger than
the negative, in order to get action.

A somewhat different type of conflict, which may be called
_vacillation_, occurs when two positive tendencies are aroused that
are inconsistent with each other, so that gratification of the one
entails renunciation of the other. Old Buridan's celebrated problem of
the ass, placed equally distant from two equally attractive bundles of
hay, and whether he would starve to death from the exact balance of
the two opposing tendencies, is a sort of parable to fit this case.
Probably the poor ass did not starve--unless he richly deserved his
name--but he may conceivably have ended the very uncomfortable state
of vacillation by running away altogether, as a human being, who is
really more subject to vacillation than any other creature, is
sometimes so much disturbed at having to decide between two
invitations for the same day as to decline both, and go fishing.
Vacillation is certainly a very unpleasant state of mind. We want
action, or else we want peace, but vacillation gives us neither. In
spite of its irksomeness, we seem sometimes almost powerless to end
it, because as soon as we have about decided on the one alternative,
what we shall miss by not choosing the other comes vividly to mind,
and swings the pendulum its way.

{531}

However it comes about that a decision is reached, it usually is
reached, and the curious fact then is that it usually sticks. A
student may vacillate long between the apparently equal attractions of
two colleges, but when he finally decides on one, the advantages of
the other lose their hold on him. Now he is all for one and not at all
for the other. Having identified himself with one college, he has
completely altered the balance of attractions, his self-assertion now
going wholly on the side of the chosen college, and even leading him
to pick flaws in the other as if to reinforce his decision. In other
words, he "rationalizes", justifies, and fortifies his decision, once
he has reached it. Some people, indeed, are abnormally subject to
vacillation and seem never to accept their own decisions as final, but
normally there are strong influences tending to maintain a decision,
once it is made: the unpleasantness of the state of vacillation and
relief at having escaped from it; the satisfaction of having a
definite course of action; and self-assertion, because we have
decided, and now this course of action is _ours_. During vacillation,
neither of the alternatives was identified with ourselves, but now we
have decided and are not going to be so weak as to change. X is our
college now and anything you say against it you say against us. Thus
the person who has decided defends himself energetically against
reopening the question.

The state of indecision and the state of decision seem thus fairly
well understood, but the process of passing from the one to the other
is often obscure. It differs from one case to another. In one case we
find the rational process of deliberation, in which each alternative
is weighed and the decision awarded to the one that promises best.
This is essentially a work of imagination: you imagine that you have
adopted the one alternative, and see how it suits you, then you do the
same with the other alternative. You think each {532} alternative
through to see how satisfactory it will be, balance one against the
other, and choose accordingly. This is ideal, but often impracticable,
since we have not the time for full deliberation, or since we cannot
trust imagination to give us a correct picture, or since we have no
common measure by aid of which to balance off different sorts of
satisfaction. Even when practicable, the deliberate way of reaching a
decision is likely to seem irksome, because of the delay involved and
the natural propensity for impulsive action. Perhaps the most common
process is a sort of partial deliberation, the two alternatives
appealing to us by turns till at some moment one makes a strong enough
appeal to secure action.

Sometimes there is a deadlock, and then we either give up deciding for
the moment, and, sleeping over the matter, find when we next take it
up that one alternative has lost its momentary attractiveness and the
other has the field; or else, feeling the irksomeness and humiliation,
almost, of being unable to make up our mind, we say, "Any decision is
better than none; here goes, then; _this_ is what I will do", so
breaking the deadlock by what seems like an arbitrary toss-up.

At other times, without such a distinct "act of will", and without any
observable change in the attractiveness of either alternative, we
simply find, after awhile, that a decision has emerged, and that we
now know what we are going to do. What has happened in us to bring
about the decision we cannot see, but here we are with a decision made
and perhaps with the act already performed. The two alternatives
remain theoretically equal, but one has somehow got hold of us, while
the other has lapsed.

Then there is the case where we "see the better, but follow the
worse", or are in great danger of so doing. The "worse" is usually
something that appeals to the {533} "old Adam" in us, something that
strongly arouses a primitive instinctive response; while the "better"
is a nobler, more dutiful, or more prudent course. The lower motive
being the stronger, how can it ever be that the higher motive gets the
decision? Well, the fight is not just a contest between these two.
Other motives are drawn into the fray, the whole man is drawn in, and
it is a question which side is the stronger. Fear of ridicule or
criticism, sense of duty, self-respect, ambition, ideals of oneself,
concern for the welfare of another person, loyalty to a social group,
may be ranged on the side of the "weaker" motive and give it the
advantage over the stronger.

_What becomes of the rejected motives?_ If unimportant and s
superficial, they simply lapse into an inactive state and are gradually
forgotten, perhaps recurring to mind once in a while with a faint
tinge of regret, since after all we should have liked to gratify them.
"As a boy, I wanted to be a sailor; well, I would rather like to try
it for once." When a motive is deeply rooted in our nature, it cannot
be so easily eliminated. Sometimes it is simply _deferred_ and remains
dormant, content to bide its time; "there will be time enough for that
later on". Sometimes it is _disguised_ and then gratified, as when an
apparently courteous deed contains an element of spite. Sometimes it
is afforded a _substitute gratification_, as when the boastful boy,
after having his "conceit taken out of him" by his mates, boasts of
his school, profession, town or country. This is often called
"sublimation". Sometimes, though denied, it remains insistent, and
"_defense mechanisms_" have to be devised to keep it down; the "sour
grapes" mechanism is an example, which may be used not only when the
"grapes" are physically out of reach but also when for any reason we
decide to leave them alone.

The psychoanalytic school lays great stress on {534} "suppressed"
desires, holding that they become _unconscious while still remaining
active_, and that they find gratification symbolically in dreams, and
at times break into waking life in a disturbing way.

The most adequate way of handling rejected motives is to _cooerdinate_
them with other, accepted motives--to harness them into teams and put
them to work. This cannot always be done; for example, if a young
woman has two attractive suitors, she might find difficulty in
harnessing them together, and will have to say good-by to one, at
least. But when the boastful boy becomes a loyal and enthusiastic
member of a school, his self-assertive motive is harnessed up with
social motives into a very effective team. Probably a tendency can
only be "sublimated" by being thus combined and cooerdinated with other
strong tendencies.

These various ways of handling a rejected motive could be nicely
illustrated from the case of the sex instinct. It so happens, partly
because modern economic and educational conditions enforce a delay in
marriage--and in part simply because there are so many attractive
people in the world--that the cravings of sex must often be denied.
What becomes of them? Of course the sex instinct is too deep-seated to
be eradicated or permanently to lapse into a dormant state. But the
fascination for particular individuals may so lapse or be forgotten.
Certain people we remember, once in a while, with half-humorous and
certainly not very poignant regret. Deferring the whole matter till
the time is ripe works well with many a youth or maiden. Combined with
social interests, the sex motive finds sublimated satisfaction in a
great variety of amusements, as well as in business associations
between the sexes. Introduce a nice young lady into an officeful of
men, and the atmosphere changes, often for the better,--which means,
certainly, that the sex motive of these men, combined with ordinary
business {535} motives, is finding a sublimated satisfaction. The sex
motive thus enters into a great variety of human affairs. "Defense
mechanisms" are common in combating unacceptable erotic impulses; the
sour grapes mechanism sometimes takes the extreme form of a hatred of
the other sex; but a very good and useful device of this general sort
is to throw oneself into some quite different type of activity, as the
young man may successfully work off his steam in athletics. This is
not sublimation, in any proper use of that term, for athletic sport
does not gratify the sex tendency in the least, but it gratifies other
tendencies and so gratifies the individual. It is the individual that
must be satisfied, rather than any specified one of his tendencies. As
regards cooerdination, the fact was illustrated just above that this
method would not always work; but sometimes it works immensely well.
Here is a young person (either sex), in the twenties, with insistent
sex impulses, tempted to yield to the fascination of some mediocre
representative of the other sex. Such a low-level attachment, however,
militates against self-respect, work, ambition, social sense. Where is
the "cooerdination"? It has to be found; some worthy mate will harness
all these tendencies, stimulating and gratifying sex attraction,
self-respect, ambition, and others besides, and cooerdinating them all
into the complex and decidedly high-grade sentiment of love.


Obstruction and Effort

The term "will" is used to designate the response to external
obstruction as well as the response to internal conflict. In fact,
nothing is so characteristically "will" as the overcoming of
resistance that checks progress towards a desired result. As
"decision" is the response to internal conflict of tendencies, so
"effort" is the response to external {536} resistance encountered in
executing a desire that has been adopted. The obstruction may be
purely physical, as the underbrush that impedes your progress through
the woods; or it may be another person's will running counter to
yours; or it may be of the nature of distraction of attention from the
end in view.

The resistance may also be internal, and consist in your own lack of
skill in executing your intentions, or in the disturbing effect of
some desire which, though rejected, has not gone to sleep but still
pulls you another way than the way you have decided to go.

In all these cases, the individual is moving towards a certain goal,
but encounters obstruction; and his response is effort, or increased
energy put into his movement towards the goal. So long as the tendency
towards a goal finds smooth going, there is not the same determination
that appears as soon as an obstruction is encountered. The "will", in
common usage, will not brook resistance--the "indomitable will".

Now effort and determination, in our chapter on the native impulses,
were put under the head of the assertive or masterful tendency; and it
does seem that "will", in this sense, is almost the same thing as the
instinct of self-assertion. Certainly, in the case of adults, an
obstruction puts the individual "on his mettle", and superimposes the
mastery motive upon whatever motive it may have been that originally
prompted the action.

The mastery motive came clearly to light in an experiment designed to
investigate "will action". The subject of the experiment was first
given a long course of training in responding to certain stimulus
words by other certain words that were constantly paired with them;
and when his habits of response were thus well fixed, his task was
changed so that now he must respond to any word or syllable by any
{537} other that _rhymed_ with it. A series of stimuli now began with
words for which no specific response habit had been formed, and to
these the subject reacted with no great difficulty. But then,
unexpectedly, he got a stimulus word to which he had a fixed habit of
response, and before he could catch himself he had made the habitual
response, and so failed to give a rhyme as he had intended. This check
sometimes made him really angry, and at least it brought him up to
attention with a feeling which he expressed in the words, "I can and
will do this thing". He was thus put on his guard, gave closer
attention to what he was doing, and was usually able to overcome the
counter tendency of habit and do what he meant to do. Some subjects,
who adapted themselves readily and fully to the rhyming task, i.e.,
who got up a good "mental set" for this sort of reaction, made few
errors and did not experience this feeling of effort and
determination; for them the effort was unnecessary; but the average
person needed the extra energy in order to overcome the resistances
and accomplish his intentions.

Other good instances of effort are found in the overcoming of
distraction, described under the head of attention, [Footnote: See p.
259.] and in the work of the beginner at any job. When the beginner
has passed the first cautious, exploratory stage of learning, he
begins to "put on steam". He pounds the typewriter, if that is what he
is learning, spells the words aloud, and in other ways betrays the
great effort he is making.

Ask a child just learning to write why he grasps the pencil so
tightly, why he bends so closely over the desk, why he purses his
lips, knits his brow, and twists his foot around the leg of his chair,
and he might answer, very truly, that it is because he cannot do this
job easily and has to _try hard_. All these unnecessary muscular
movements and tensions {538} show the _access of energy_ that has been
liberated in his brain by the obstruction encountered.

Any learner, once he has mastered the difficulties of the task,
reaches an easy-running stage in which effort is no longer required,
unless for making a record or in some way surpassing himself. With
reference to effort, then, we may speak of three stages of practice:
the initial, exploratory stage, the awkward and effortful stage, and
the skilled and free-running stage. These are identical with the three
stages in the development of attention to a subject, which were
described [Footnote: See p.258] as the stage of spontaneous attention
or curiosity; the stage of forced attention, or effortful attention,
controlled by such motives as fear or self-assertion; and the final
stage of objective interest and absorption in the subject, which is
evidently the same as the free-running condition.

Effort is not a good in itself; it is an unpleasant condition; but it
is a natural response to difficulty and is often necessary in order to
get the individual into the free-running condition which is both
efficient and pleasant. It is often required to get the individual out
of the easy-going condition into the free-running condition, which is
something entirely different. In free-running action there may be even
more energy expended than in effortful action, but it is better
directed and produces no strains and jolts.

Intelligence, in the sense of adaptability and "seeing the point", may
often take the place of effort. Consider the way two different people
react to a sticking door: the one puts in more strength and forces it,
the other by a deft thrust to the side opens it without much extra
force. You can't say absolutely which mode of attack is better, for
your stubborn one may waste his strength on an obstruction that really
cannot be forced, while your clever one may waste his {539} time on a
door that needs only a bit of a push. Persistence _plus_ adaptability
is what efficient activity demands.


Thought and Action

"Men of thought" and "men of action" are sometimes contrasted--which
is hardly fair to either, since the great man of action must have the
imagination to conceive a plan, and must know exactly what he is
aiming to accomplish, while the great thinker must be persistent in
thinking and must get into action by way of writing or somehow making
his thoughts count in the world. But we do find men who are impatient
of thought and want to get into action at once, even without knowing
just what they are about, and other men who seem quite contented to
think and plan, without any definite intention of ever putting their
plans into execution. The former type, the impulsive individual, is
not difficult to understand, his behavior fits in so well with the
primitive trial-and-error sort of activity; but the mere thinker seems
an anomaly, in view of the general psychological principle that
thought tends toward motor action.

In accounting for the inactive thinker, we have to remember, first,
that some inhibition of immediate action is often necessary, in order
to have time to think the matter over; this prudent attitude becomes a
habit with some individuals. Besides, there are the negative motives
of fear, shyness and laziness that tend to deter from the actual
execution of a plan. Hamlet's "conscience" that makes "cowards of us
all", so that "the native hue of resolution is sicklied o'er with the
pale cast of thought, and enterprises of great pith and moment . . .
lose the name of action" turns out, if we look a few lines further
back, to be the "dread of something" unknown, that "puzzles the will,
and makes us rather bear those ills we have than fly to others that we
know not of". {540} Fear--fear of unforeseen consequences, fear of
committing ourselves, fear of ridicule--is one great inhibiter of
action, and inertia is another, since it is much less strenuous to sit
in the armchair and plan than to get out and put the plan into effect.
Besides this, some people who are good at planning come to take so
much pride and satisfaction in the thinking part of an enterprise that
they do not feel the need for action. Moreover, you can "plan" in a
large way, without bothering about details, but once you start to
execute your plan you encounter details and preliminaries which are
apt to rob the enterprise of its zest. Here is where persistence and
effort are needed.

_Abulia_--"no will"--is an abnormal degree of lack of zest for action.
Along with it go timidity and lack of social force, proneness to
rumination and daydreaming, and often a feeling of being compelled to
perform useless acts, such as doing everything three times or
continual washing of the hands. Abulia is not just a comfortable
laziness, but is attended by a sense of humiliation and inferiority.
It shows itself in excessive hesitation and vacillation and in failure
to accomplish anything of consequence. Sometimes the subject expends
much effort, but fails to direct the effort towards the execution of
his purposes. Some authorities have ascribed abulia to inertia or "low
mental tension", some to an overdose of fear and caution, some to the
paralyzing effect of suppressed desires still living in the
"unconscious". Mild degrees of it, such as are not uncommon, seem
sometimes to be due to the hiatus that is bound to exist between the
end one has in view and the means one must take to start towards that
end. One has zest for reaching the goal, but not for the
preliminaries.

An author, whose case was studied because he was accomplishing so
little, was found to follow a daily program about as follows. He would
get up in the morning full of {541} confidence that this was going to
be a good day, with much progress made in his book. Before starting to
write, however, he must first have his breakfast, and then a little
fresh air, just to prepare himself for energetic work. On returning
from his walk, he thought it best to rest for a few moments, and then
one or two other little matters seemed to demand attention; by the
time these were done, the morning was so far gone that there was no
time for a really good effort, so he optimistically postponed the
writing till the afternoon, when the same sort of thing happened, and
the great performance had to be put over till the next day. This man
did better under a regime prescribed by his medical adviser, who
commanded him to write for two hours immediately after rising, and
make this his day's work--no more and no less than two hours. The
definiteness of this task prevented dawdling.

Other writers have noted a curious tendency to "fight shy" of the
passage actually being written and let the thoughts move ahead and
plan out the later passages. Sometimes it is necessary to trick
yourself if you are to get anything done; you say, "I can't write this
properly just now; I'll just sketch out a preliminary draft"--on which
understanding you may be able to write, whereas you could not if you
thought you were writing "for keeps"; but when you have got well
started and warmed to the task, you may find your work good enough to
keep, after all. Judging by these mild cases, abulia may be due partly
to distaste for the details of actual performance, and partly to a
dread of committing oneself to anything that has the stamp of
finality.


Securing Action

No chapter in psychology offers more in the way of practical
applications than this chapter on the will--if we only {542} knew more
on the subject! How to get action, either from yourself, or from
others if you are responsible for their action, is a big practical
problem. A few hints on the matter are suggested by what precedes.

How to get action from yourself--how to liberate your latent energies
and accomplish what you are capable of accomplishing. A definite
purpose is the first requirement; without that one merely drifts, with
no persistency and no great energy. The goal should be something that
appeals vitally to you, and something which you can attain; not too
distant a goal; or, if the ultimate goal is distant, there must be
mileposts along the way which you can take as more immediate goals;
for a goal that can be reached by immediate action enlists more
present effort. The student puts more energy into his study when the
examination is close at hand; and, although this is regrettable, it
reveals a fact in human nature that can be utilized in the management
of yourself or others. A well defined and clearly visible goal is a
much better energy-releaser than vague "good intentions".

The more clearly you can see and measure your approach towards the
goal, the more action; thus it has been found in many different lines
that the "practice curve method" of training gives quicker and better
results than ordinary drill. In the practice curve [Footnote: See p.
321.] you have a picture of your progress; you are encouraged by
seeing how far you have advanced, and stimulated to surpass your past
record, and thus your immediate goal is made very definite. You cannot
do so well when you simply "do your best" as when you set out to reach
a certain level, high enough to tax your powers without being quite
out of reach. You cannot jump so high in the empty air as you can to
clear a bar; and, to secure your very best endeavor, the bar must not
be so low {543} that you can clear it easily, nor so high that you
cannot clear it at all.

The goal should be heartily adopted as _your_ goal, which is to say
that the self-assertive motive should be harnessed into service. The
importance of this motive in securing action is seen in the strong
effect of competition to arouse great activity. The runner cannot make
as good speed when running "against time" as when competing directly,
neck to neck, with other runners. Hence, to get full action from
yourself, find worthy competitors. And for the same reason, accept
responsibility. This puts you on your mettle. To shun competition and
responsibility is characteristic of abulia. Other strong motives, such
as the economic motive or the sex motive (seen in the energetic work
of a young man whose goal is marriage to a certain young woman) can
also be enlisted in many cases. But, for the best results, there
should be, in addition to these extraneous motives, a genuine interest
in the work itself.

Do not say, "I will try". Say, "I will do it". The time for trying, or
effort, is when obstruction is actually encountered. You cannot really
try then, unless you are already fully determined to reach the goal.

Getting action from other people is the business of parents, teachers,
bosses, officers, and to some extent of every one who wishes to
influence another. In war, the problem of "morale" is as important as
the problem of equipment, and it was so recognized by all the armies
engaged in the Great War. Each side sought to keep the morale of its
own soldiers at a high level, and to depress the morale of the enemy.
Good morale means more than willingness for duty; it means "pep", or
positive zest for action. Some of the means used to promote morale
were the following. The soldier must believe in the justness of his
cause; that is, he must make victory his own goal, and be {544}
whole-hearted in this resolve. He must believe in the coming success
of his side. He must be brought to attach himself firmly to the social
group of which he forms a part. He must be so absorbed in the
activities of this group as to forget, in large measure, his own
private concerns. Not only must he be enthusiastic for cause and
country, but he must be strong for his division, regiment and company.
Much depends on the officers that directly command him. He must have
confidence in them, see that they know their business, and that they
are looking out for the welfare of their men as well as expecting much
from them. Competition between companies, regiments, and arms of the
service was a strong force tending towards rapid progress in training
and good service in the field. Interest in the actual technical work
that was being done, and seeing that one's immediate group was
accomplishing something towards the winning of the war was a powerful
spur, while a sense of the uselessness of the work in hand strongly
depressed the morale of a group. "Nothing succeeds like success";
morale was at its best when the army was advancing and seemingly
nearing the goal. Morale was also wonderfully good when the enemy was
advancing, provided your side was holding well with a good prospect of
bringing the enemy to a halt and baffling his offensive. On the other
hand, nothing was so hard on morale as the failure of an ambitious
offensive of one's own side; the sense of futility and hopelessness
then reached its maximum--except, of course, for the case of obviously
approaching defeat. The conditions of trench warfare imposed a strain
on morale: no progress, in spite of the danger and hardship, no chance
to get at the enemy or do anything positive.

The manager of an industrial enterprise has the same problem of morale
to meet. It is his business to get action from people who come into
the enterprise as servants. The {545} main difficulty with the
master-servant relation is that the servant has so little play for his
own self-assertion. The master sets the goal, and the servant has
submissively to accept it. This is not his enterprise, and therefore
he is likely to show little "pep" in his work. He can be driven to a
certain extent by fear and economic want; but better results, and the
best social condition generally, can be expected from such management
as enlists the individual's own will. He must be made to feel that the
enterprise is his, after all. He must feel that he is fairly treated,
and that he receives a just share of the proceeds. He must be
interested in the purposes of the concern and in the operations on
which he is engaged. Best of all, perhaps, some responsibility and
initiative must be delegated to him. When the master, not contented
with setting the main goal, insists on bossing every detail,
continually interfering in the servant's work, the servant has the
least possible chance of adopting the job as _his own_. But where the
master is able, in the first place, to show the servant the objective
need and value of the goal, and to leave the initiative in respect to
ways and means to the servant, looking to him for results, the servant
often responds by throwing himself into the enterprise as if it were
his own--as, indeed, it properly is in such a case.

"Initiative"--that high-grade trait that is so much in demand--seems
to be partly a matter of imagination and partly of will. It demands
inventiveness in seeing what can be done, zest for action, and an
independent and masterful spirit.

The physician who treats "nervous" or neurotic cases has this problem
of getting action from his patients. Strange as it may seem, these
cases, while bemoaning their unfortunate condition, cling to it as if
it had its compensations, and do not wholeheartedly _will to get
well_. They have {546} slumped into the attitude of invalidism, and
need reorientation towards the goal of health and accomplishment. How
to bring this about is the great problem. Much depends here on the
personality of the physician, and different physicians (as well as
mental healers outside the medical profession) employ different
technique with more or less of success. The first necessity is to win
the patient's confidence; after that, some use persuasion, some
suggestion, some psychoanalysis, some (non-medical practitioners) use
metaphysical doctrines designed to lead the patient to "hitch his
wagon to a star". On the intellectual side, these methods agree in
giving the patient a new perspective, in which weakness, ill health
and maladaptation are seen to be small, insignificant and unnecessary,
and health and achievement desirable and according to the nature of
things; while on the side of impulse they probably come together in
appealing to the masterful and self-assertive tendency, either by
putting the subject on his mettle, or by leading him to partake of the
determined, masterful attitude of the physician, or by making him feel
that he is one with the great forces of the universe. Methods that
psychologically are very similar to these are employed by the
clergyman in dealing with morally flabby or maladjusted individuals;
and the courts are beginning to approach the delinquent from the same
angle. All the facts seem to indicate that the way to get action is to
have a goal that "fires the imagination" and enlists the masterful
tendencies of human nature.


The Influence of Suggestion

Can the will of one person be controlled by that of another, through
hypnotism or any similar practice? This question is often asked
anxiously by those who fear that crime or misconduct willed by one
person may be passively executed by another.

{547}

Hypnosis is a sleeplike and passive state that is nevertheless
attentive and concentrated. It appears as if the subject were awake at
just one point, namely at the point of relation with the hypnotizer.
To stimuli from other sources, external or internal, he is
inaccessible. His field of activity is narrowed down to a point,
though at that point he may be intensely active.

The depth of the hypnotic state varies from shallow to profound.
Comparatively few individuals can be deeply hypnotized, but many can
be got into a mild receptive state, in which they accept the
suggestions of the hypnotizer more readily than in the fully awaking
state. The waking person is alert, suspicious, assertive, while the
hypnotized subject is passive and submissive. The subject's
cooeperation is necessary, in general, in order to bring on the
hypnotic state, whether shallow or deep.

The means of inducing hypnosis are many and varied, but they all
consist in shoving aside extraneous thoughts and stimuli, and getting
the subject into a quiet, receptive attitude, with attention sharply
focussed upon the operator.

When the subject is in this state, the "suggestions" of the operator
are accepted with less criticism and resistance than in the fully
waking state. In deep hypnosis, gross illusions and even
hallucinations can be produced. The operator hands the subject a
bottle of ammonia, with the assurance that it is the perfume of roses,
and the subject smells of it with every appearance of enjoyment. The
operator points to what he says is a statue of Apollo in the corner,
and the subject apparently sees one there.

Loss of sensation can also be suggested and accepted. Being assured
that his hand has lost its sensation and cannot feel a pin prick, the
subject allows his hand to be pricked with no sign of pain. Paralysis
of the arm or leg can be similarly suggested and accepted.

{548}

Acts may be suggested and performed. The subject is handed a cardboard
sword with the assurance that that is a sword, and directed to attack
some person present, which he does with the appearance of serious
intent.

Now, however, let the subject be given a real sword with the same
command as before. Result--the subject wakes up! This suggestion was
too much; it aroused dormant tendencies, broadened out the field of
activity, and so produced the waking condition. A suggestion that runs
counter to the subject's organized character and tendencies cannot get
by without arousing them and so awakening the subject. Consequently,
there does not seem to be much real danger of crimes being performed
by innocent persons under hypnosis.

In mild hypnosis, the above striking phenomena are not produced, but
suggestions of curative value may be conveyed, and so taken to heart
that they produce real results. The drowsy state of a child just
falling to sleep can be similarly utilized for implanting suggestions
of value. One little boy had a nervous twitching of the face that was
very annoying. His father, just as the child was dropping off to
sleep, conveyed the suggestion that the child didn't like this
twitching; and this suggestion, repeated night after night, in a few
days caused the twitching almost wholly to disappear.

Suggestion often succeeds in a waking state. In a certain test for
"suggestibility", the task is set of copying a series of lines. The
first line is short, the second longer, the third longer still, the
rest all of the same length, but the more suggestible individual keeps
on making each succeeding line longer. There are, however, various
tests for suggestibility, and an individual who succumbs to one does
not necessarily succumb to another, so that it may be doubted whether
we should baldly speak of one individual as more suggestible than
another.

{549}

Suggestion may be exerted by a person, or by the circumstances. If by
a person, the more "prestige" he enjoys in the estimation of the
subject, the greater his power of suggestion. A prestige person is one
to whom you are submissive. A child is so dependent on older people,
and so much accustomed to "being told", that he is specially
susceptible to prestige suggestion.

Suggestion exerted by the circumstances is about the same as what is
often called "auto-suggestion" or "self-suggestion". A man falls and
hurts his hip, and, finding his leg difficult to move, conceives that
it is paralyzed, and may continue paralyzed for some time.

"Counter-suggestion" applies to cases where a suggestion produces the
result contrary to what is suggested. You suggest to a person that he
should do a certain thing, and immediately he is set against that act,
though, left to himself, he would have performed it. Or, you advance a
certain opinion and at once your hearer takes the other side of the
question. Quite often skilful counter-suggestion can secure action,
from children or adults, which could not be had by positive suggestion
or direct command.

If suggestion succeeds by arousing the submissive tendency,
counter-suggestion succeeds by arousing the assertive tendency.
Suggestion works when it gets response without awakening the
resistance which might be expected, and counter-suggestion when it
arouses so much resistance that the suggestion itself does not have
the influence which might be expected. In terms of stimulus and
response, suggestion works when a particular stimulus (what is
suggested) arouses response without other stimuli being able to
contribute to the response; and counter-suggestion works when a
stimulus (what is suggested, again) is itself prevented from
contributing to the response. In counter-suggestion, response to the
suggestion itself is inhibited, and in positive {550} suggestion
response to other stimuli is inhibited. Both involve narrowness of
response, and are opposed to what we commonly speak of as "good
judgment", the taking of all relevant stimuli into account, and
letting the response be aroused by the combination.

{551}

EXERCISES

1. Outline the chapter.

2. Which of the previous chapters have the closest contacts with
   the present chapter?

3. How does the popular conception of hypnotism differ from the
   scientific?

4. List 8 acts performed during the day, and arrange them in order
   from the most involuntary to the most voluntary.

5. Analyze a complex performance so as to show what in it is voluntary
   and what involuntary.

6. Mention an instance of practice changing a voluntary performance
   into an involuntary, and one of practice changing an involuntary
   performance into a voluntary.

7. If an individual is influenced by two opposing motives, must he
   act according to the stronger of the two?

8. Illustrate, in the case of anger, several ways of dealing with a
   rejected motive. i.e., in what different ways can anger be
   controlled?

9. How would you represent purpose in neural terms? How does
   it compare with "mental set"?


REFERENCES

On the importance of self-assertion (and of submission) in will, and
on the relation of conduct to impulse and to reasoning, see
McDougall's _Social Psychology_, Chapter IX, on "Volition", and
Supplementary Chapter I, on "Theories of Action".

For a practical study of the question, how to secure action, see
Walter Dill Scott's _Increasing Human Efficiency in Business_, 1911.

On hypnotism, see Albert Moll's _Hypnotism_, translated by A. F.
Hopkirk; or James's Chapter XXVII in his _Principles of Psychology_,
1890.

{552}

CHAPTER XXI

PERSONALITY

THE INDIVIDUAL AS A WHOLE, INTEGRATED OR PARTIALLY DISSOCIATED

People differ not only in intelligence and efficiency, but in an
intangible something referred to as "personality". If your
acquaintance is applying for a certain position, and has named you as
one of his references, you will be asked by the appointing officer to
tell what you know of the candidate's experience, his knowledge and
skill in the field where he desires a position, his character and
habits, and his _personality_; and in replying you state, if you
conscientiously can, that the candidate has a pleasing and forceful
personality, that he gets on well with superiors, equals and
inferiors, is cooeperative, energetic, ambitious without being selfish,
clean, modest, brave, self-reliant, cheerful, optimistic,
equal-tempered; and you perhaps include here traits that might also be
classed under the head of "character", as honesty, truthfulness,
industry, reliability, and traits that might be classed under
physique, as good appearance and carriage, commanding presence, a
"strong face", and even neatness and good taste in dress. Here we have
an array of traits that are of great importance to the individual's
success in his work, in his social relationships and in his family
life; and it is a proof of how much remains to be accomplished in
psychology that we cannot as yet present anything like a real
scientific analysis of personality, nor show on what elementary
factors it depends.

{553}

Factors in Personality

If we do attempt some sort of analysis, we have first to notice that
personality depends in part on _physique_. In ordinary life, mental
and physical traits are not sharply distinguished, and probably they
cannot be distinguished except in the abstract. The mere size of a
person affects his attitude towards other people and their attitude
towards him--and it is in such social relations that personality most
clearly stands out. His size affects the individual's behavior in
subtle ways, since the big fellow dominates others easily just by
virtue of his size, and so tends to be good-humored, while the little
fellow is apt to be strenuous and self-assertive. Muscular development
and "looks" also have their effect on personality.

Another factor might, by a sort of play on words, be called
_chemique_. This corresponds to what is often called _temperament_, a
very obscure matter psychologically. We speak of one as having an
excitable temperament, a jovial or a sour temperament. "Disposition"
is another word used in connection with such traits. The ancients
attempted to relate the "four temperaments" to the four great "humors"
or fluids of the body. Thus the "sanguine" individual was one with a
surplus of blood, the "choleric" had a surplus of bile, the
"phlegmatic" a surplus of phlegm, and the "melancholic" a surplus of
black bile or spleen; and any individual's temperament resulted from
the balance of these four. Sometimes a fifth temperament, the nervous,
was admitted, dependent on the "nerve fluid".

This particular chemical derivation of temperament is, of course, out
of date, being based on very imperfect knowledge of physiology; but it
still remains possible that chemical substances carried around in the
body fluids have much to do with the sort of trait that we think of
under {554} the head of temperament. Only that to-day, with some
knowledge regarding the internal secretions of the "endocrine glands",
we should be inclined to connect temperament with them, rather than
with blood, bile, etc. Take, for example, the secretion of the adrenal
glands, that we found to be poured out during fear and anger and to
have so much to do with the bodily condition of readiness for violent
action and probably also with the "stirred-up" emotional state. What
is more likely than that individuals differ in the strength of their
adrenal secretion or in the readiness with which the glands are
aroused to pour it out into the circulation? The excitable individual
might be one with over-active adrenals. And in the same way the
strenuous individual might be one with an unusually active thyroid
gland, since there certainly seems to be some connection between this
gland and the tendency to great activity. There are several other
glands that possibly affect behavior in somewhat similar ways, so that
it is not improbable, though still rather hypothetical, that chemical
substances, produced in these glands, and carried by the blood to the
brain and muscles, have much to do with the elusive traits that we
class under temperament and personality.

Once more, consider the instincts in relation to personality.
Undoubtedly these instinctive tendencies differ in strength in
different individuals. One is more gregarious than another, and this
is an important element in his personality. One is more assertive and
masterful than another, one is more "motherly" than another, more
responsive by tender and protective behavior to the presence of
children or others who need help. One is more prone to laugh than
another, and the "sense of humor" is admitted to be an important
element in personality. And so on through the list; so that
personality can be partially analyzed in terms of instinct.

{555}

Has _intelligence_ anything to do with personality? It certainly has,
in many ways. One who is slow in learning adapts himself poorly to
other persons and remains out of touch with his social environment.
"Tact" depends partly on instinctive liking for society, no doubt, but
partly on the ability to perceive what others want, and on the
imagination to put yourself in their place. High principles require
the ability to reason things out and see them in perspective.
Statistical studies of the rulers of Europe, for a period of several
centuries, show that on the whole those with higher intelligence were
also of better character and personality. Criminals, taken as a whole,
average rather low in intelligence; and it may even be doubted whether
the clever, scheming rascal, who defrauds widows of their money, or
trains feeble-minded boys to pick pockets for him, has, after all, the
brains of the man who can easily see how such schemes could be worked
but decides against them himself because he sees something better
worth doing.

A sense of inferiority, either physical or mental, is apt to affect
the personality unfavorably. It does not necessarily produce humble
behavior; far from that, it often leads to a nervous assertiveness. An
apparently disdainful individual is often really shy and unsure of
himself. Put a man where he can see he is equal to his job and at the
same time is accomplishing something worth while, and you often see
considerable improvement in his personality.


The Self

In a broad, objective sense, the self is the individual, but in a more
subjective sense the self is what the individual knows about himself,
how he conceives himself, how he feels about himself, what he plans
and wishes for himself. It is reasonable to suppose that the newly
born infant does not {556} distinguish himself from other objects.
Perhaps his foot, as he sees it, seems simply an object among others,
like a toy; but he soon learns to connect the visual appearance with
the cutaneous and kinesthetic sensations from the foot, and these
sensations, along with the organic, always retain in large measure the
subjective quality of belonging to the self, whereas sights, sounds,
odors and tastes seem to belong to objects distinct from the self.

If we ask how the child comes to make the distinction between the self
and the not-self, we have to call to mind the assertiveness that
manifests itself very early in the child's behavior--how he resists
being pushed and pulled about, struggles against being held, and in
many ways, more and more complex as he develops, shows that he has a
"will of his own". It is in resisting and overcoming external things
that he comes to distinguish himself from them.

Not only external things, but other _persons_ particularly, have to be
encountered and resisted by the child; and often, too, he has to
submit to them, after a struggle. Probably he distinguishes between
himself and other people even more sharply than between himself and
inanimate things. Ask any one to tell you what he knows about himself,
and he will begin to tell you how he differs from others. Thus the
individual's conception of himself is largely a product of his social
experience.

The self is first known as wish or will, and probably that always
remains the core of any one's conception of himself. That is to say, I
think of myself first of all as wishing, aiming, purposing, resisting,
striving, competing. But I may come to know myself more objectively.
By dint of experience I know something of my limitations. I know I am
not muscular enough to do this, nor mathematical enough to do that,
nor artistic enough to do the other. In this progressive age, some
children even know their own IQ. We {557} have frequent occasion to
measure ourselves against others, or against tasks, and lay some of
the lessons to heart. Though most of us are probably inclined to
overrate ourselves, many will be found to give a pretty exact estimate
of themselves. It is surprising that this should be so, in view of the
tendency to believe what one wishes, and of the deep-seated desire for
superiority or at least against inferiority. It shows that, after all,
there is a good deal of fidelity to fact in our make-up.

The word "self-assertion", which has been used more or less throughout
the book as a name for the native tendency to resist, persist, master,
dominate, display oneself and seek social recognition, can now be seen
to be not entirely a good word for the purpose. It seems to imply that
the self-assertive individual is necessarily conscious of the self.
From what has just been said, it can be seen that this would be
putting the cart before the horse. The self-assertive impulse
precedes, consciousness of self follows and depends on self-assertion.
A true estimate of oneself and one's limitations arises from
self-assertion plus experience of failure and the necessity of giving
up and submitting.

Self-assertion is not identical with selfishness. Selfishness aims to
get, self-assertion to do. Selfish behavior is, however, often
dictated by self-assertion, as when a person wishes to get and have,
in order to be able to show by his possessions what a great man he is.
But sometimes self-assertion squelches selfishness, leading a person
to renounce present gain without hope of later gain in compensation,
just because he sees in such renunciation the best chance for mastery
and proving himself "the captain of his soul".

The "expansion of the self" is an interesting and significant
phenomenon. The individual comes to call things, persons, social
groups, ideas and principles by the name {558} "mine". Now what is
mine is part of me. My self-feeling attaches to my dog; I am proud of
that dog, brag of his exploits, am cast down if I see him outclassed;
and it is the same way with my house, my son, my town, my country. We
spoke of this sort of thing before, under the name of "sublimation of
the self-assertive impulse", and we said then that the sublimation was
made possible by the combination of this impulse with some other
interest. My dog is not entirely myself; he is a dog, and I am
interested in him as a dog; I am interested in other dogs, and like to
watch their antics. But this particular dog means more than another to
me because he is mine; I have expanded myself to include him. In
general, the self is expanded to take in objects that are interesting
in themselves, but which become doubly interesting by being
appropriated and identified in some measure with oneself.


Integration and Disintegration of the Personality

Though the individual is always in one sense a unit, there is a sense
in which he needs to achieve unity. His various native tendencies and
interests do not always pull together, and in fact some necessarily
pull against others. So that we sometimes say of a person that he is
behaving so differently from usual that we should not know he was the
same person. We may speak of one person as being well integrated,
meaning that he is always himself, his various tendencies being so
cooerdinated as to work reasonably well together; whereas of another we
speak as poorly integrated, unstable, an uncertain quantity.
Integration is achieved partly by selection from among conflicting
impulses, partly by cooerdination, partly by judicious treatment of
those impulses that are denied; as was partly explained in the last
chapter.

{559}

The self, expanding socially, may expand in more than one direction,
with the result that the individual has in a sense two or more selves,
one for his business, one for his home; and it may happen that the
instincts and interests dominating the individual in these two
relations are quite different, so that a man who is hard and grasping
in business is kind and generous to his wife and children. "Dr. Jekyll
and Mr. Hyde" gives an extreme picture of such lack of integration, a
picture rather fanciful than drawn from real life.

But we do find in real life cases of _dissociation_ of the
personality, also called cases of double or multiple personality. The
individual passes from one state to another, behaving very differently
in the two states, and usually unable to remember in the primary or
more lasting state what he has done in the secondary state. In the
secondary state he remembers what he did in the primary state, but is
apt to speak of it as if done by another person. In many cases, the
primary state seems limited and hampered, as if the individual were
not his complete self, while the secondary state is a sort of
complement to the first, but decidedly imperfect in itself. Thus in
the primary state the individual may be excessively quiet, while in
the secondary state he is excessively mischievous. It is much as if
some of his reaction-tendencies were forcibly kept apart from the
rest, so that when they did become aroused to activity, the remainder
of the individual went to sleep. The individual seems to function in
fractions, and never as a whole.

Often the secondary state likes to have a name for itself and to be
considered as a secondary personality, as if two persons were
inhabiting the same body--a very forced conception. The secondary
personality will even assert that it stays awake in the background and
watches the primary personality when the latter is active, spying on
it without {560} that personality being aware of it. Thus two
fractions of the individual would be functioning at the same time, but
still not working together as a unit.

This claim of the secondary personality has been experimentally
checked up by Dr. Morton Prince, in the following way. He was able to
cause his subject, a young woman, to pass from the primary to the
secondary state and back again, by a procedure resembling hypnotism.
While she was in the secondary state, he told her that she (the
secondary personality) was to solve an arithmetical problem, the
general nature of which he described to her then and there, while the
actual numbers were not shown till she was put back in the primary
state. He then put her into the primary state for a few moments, and
placed the numbers unobtrusively before her, without the primary
personality seeming to notice them. Put back now into the secondary
state, she instantly shouted out the answer to the problem, and
asserted that she (the secondary personality) had had the answer ready
for some time, and had been impatiently waiting to be brought back and
announce it. This is at least prima facie evidence in favor of Dr.
Prince's view, that two separate fractions of the individual were both
functioning consciously at the same time.

It is weird business, however interpreted, and raises the question
whether anything of the same sort, only milder in degree, occurs in
ordinary experience. Here is one somewhat similar fact that we are all
familiar with: we have two matters in hand at the same time, very
different in their emotional tone, one perhaps a worrisome matter of
business, the other an interesting personal matter; and the shift from
one to the other feels almost like changing personalities. Also, while
busy with one, we may sometimes feel the other stirring, just barely
awake and dimly conscious.

Also, is not something like this true?--A person, very {561}
conscientious in the performance of his duties, always doing what he
is told, feels stirrings of a carefree, independent spirit, as if some
sides of his nature were not finding expression, and in little ways he
gives it expression, not exactly by taking a "moral holiday"
[Footnote: This is one of William James's expressive phrases.] or
going on a spree of some sort, but by venting his impulses just an
instant at a time, so that he scarcely remembers it later, and in such
little ways that other people, also, are scarcely aware of It. He has
a "secondary personality", only it is little developed, and it has its
little place in the conscious life, instead of being dissociated.

In the cases of true dissociation, there was often a violent emotional
shock that started the cleavage. One celebrated case started at 8
years of age, when the subject, a little girl, was thrown to the floor
by a drunken father angered by finding the child asleep in his bed.
From that moment, it would seem that the frolicsome side of childish
behavior was banished from the main personality, and could get into
action only when the main personality relaxed its control and became
dormant; so that thereafter the child alternated between two states,
one very quiet, industrious and conscientious, the other vivacious and
mischievous; and the main personality never remembered what was done
in this secondary, mischievous state. In such cases, it would appear
that the cleavage resulted from a violent thrusting out from the main
personality of tendencies inconsistent with the dominant (here
serious) attitude of that personality.


The Unconscious, or, the Subconscious Mind

Here at last, it may strike the reader, we have come to the core of
the whole subject of psychology; for many readers will undoubtedly
have been attracted by the statements {562} sometimes made, to the
effect that the "unconscious" represents the deeper and more
significant part of mental life, and that psychologists who confine
their attention mostly to the conscious activities are treating their
subject in a very partial and superficial manner. There is a sort of
fascination about the notion of a subconscious mind, and yet it will
be noticed that psychologists, as a rule, are inclined to be wary and
critical in dealing with it. Let as take up in order the various sorts
of unconscious mental processes.

In the first place, _retention is unconscious_. The host of memories
that a person possesses and can recall under suitable conditions is
carried about with him in an unconscious condition. But there need be
no special mystery about this, nor is it just to speak about memories
being "preserved in the unconscious". The fact simply is that
retention is a resting condition, whereas consciousness is an active
condition. Retention is a matter of brain structure, neurone
connections, neural mechanisms ready for action when the proper
stimulus reaches them but remaining inactive till the stimulus comes.
An idea is like a motor reaction, to the extent that it is a reaction;
and we retain ideas in the same way that we retain learned motor
reactions. Now no one would think of saying that a learned motor
reaction was retained in the unconscious. The motor reaction is not
present at all, until it is aroused; the neuro-muscular mechanism for
executing the reaction is present, but needs a stimulus to make it
active and give the reaction. In the same way, an idea is not present
in the individual except when it is activated, but its neural
mechanism is present, and unconscious just because it is inactive.

Unconscious inactivity is therefore no great problem. But there is
such a thing as _unconscious activity_. Two sorts of such activity are
well known. First, there are the {563} purely "physiological"
processes of digestion, liver and kidney secretion, etc. We are quite
reconciled to these being unconscious, and this is not the sort of
unconscious activity that gives us that fascinatingly uncanny feeling.
Second, there are the "secondarily automatic" processes, once
conscious, now almost or quite unconscious through the effect of
frequent repetition.

Such unconscious activities occur as _side-activities_, carried on
while something else occupies attention, or as _part-activities_ that
go on while attention is directed to the total performance of which
they are parts. In either case, the automatism may be motor or
perceptive, and the degree of consciousness may range from moderate
down to zero. [Footnote: See pp. 265-267.]

For example, the letters of your name you write almost unconsciously,
while fully conscious of writing your name. When you are reading, the
letters are only dimly conscious, and even the words are only
moderately conscious, while the whole performance of reading is highly
conscious. These are instances of unconscious (or dimly conscious)
part-activities. Unconscious side-activities are illustrated by
holding your books firmly but unconsciously under your arm, while
absorbed in conversation, by drumming with your fingers while puzzling
over a problem, and by looking at your watch and reading the time, but
so nearly unconsciously that the next instant you have to look again.
In all such cases, the unconscious or barely conscious activity has
been made easy by previous practice, and there is no special
fascination about it, except such as comes through the use of that
awesome word, "unconscious".

But now for the real "subconscious mind". You try to recall a familiar
name, but are stuck; you drop the matter, and "let your subconscious
mind work"; and, sure enough, after a few minutes you have the name.
Or, you are all {564} tangled up in a difficult problem; you let the
subconscious mind work on it overnight, and next morning it is
perfectly clear. Just here it is that psychology begins to take issue
with the popular idea. The popular interpretation is that work has
been done on the problem during the interval when it was out of
consciousness--unconscious mental work of a high order. But is it
necessary to suppose that any work has been done on the problem during
the interval?

The difficulty, when you first attacked the problem, arose from false
clues which, once they got you, held you by virtue of their "recency
value". [Footnote: See pp. 390-391.] The matter laid aside, these
false clues lost their recency value with lapse of time, so that when
you took the matter up again you were free from their interference and
had a good chance to go straight towards the goal.

It is the same with motor acts. On a certain day, a baseball pitcher
falls into an inefficient way of handling the ball, and, try as he
may, cannot recover his usual form. He has to give up for that day,
but after a rest is as good as ever. Shall we say that his
subconscious mind has been practising pitching during the rest
interval? It is much more likely that here, as in the preceding case,
the value of a fresh start lies in freshness, in rest and the
consequent disappearance of interferences, rather than in any work
that has been done during the interval of rest.

Next, consider the "co-conscious" as Morton Prince has well named
the presence and activity of the secondary personality along with the
primary, as in his experiment described above. Here it seems that two
streams of consciousness were flowing along side by side within the
same individual. There is the activity of the main personality, and
there is the activity of the secondary personality, going on at the
same time without the knowledge of the main {565} personality. This is
a way of reading the facts, rather than a simple statement of fact,
but at least it is a reasonable interpretation, and worthy of
consideration.


Unconscious Wishes and Motives

Schopenhauer wrote much of the "will to live", which was, in his view,
as unconscious as it was fundamental, and only secondarily gave rise
to the conscious life of sensations and ideas. Bergson's "elan vital"
has much the same meaning. In a sense, the will to live is the
fountain of all our wishes; in another sense, it is the sum total of
them all; and in another sense, it is an abstraction, the concrete
facts consisting in the various particular wishes and tendencies of
living creatures. The will to live is not simply the will to stay
alive; it is the will to _live_ with all that that includes. Life is
activity, and to live means, for any species, to engage in the full
activity possible for that species.

The will to live is in a sense unconscious, since it is seldom present
simply in that bald, abstract form. But since life is activity, any
will to act is the will to live in a special form, so that we may
perfectly well say that the will to live is always conscious whenever
there is any conscious impulse or purpose.

In this simple statement we may find the key to all unconscious
motives, disregarding the case of dissociation and split personality.
If you analyze your motives for doing a certain act and formulate them
in good set terms, then you have to admit that this motive was
unconscious before, or only dimly conscious, since it was not
formulated, it was not isolated, it was not present in the precise
form you have now given it. Yet it was there, implicated in the total
conscious activity. It was not unconscious in the sense of being
active in a different, unconscious realm. The realm in which it was
active was that of conscious activity, and it formed an {566}
unanalyzed part of that activity. It was there in the same way that
overtones are present in perceiving the tone quality of a particular
instrument; the overtones are not _separately_ heard and may be very
difficult to analyze, yet all the time they are playing an important
part in the conscious perception.

In the same way, we may not "realize" that we are helping our friend
as a way of dominating over him, but think, so far as we stop to
think, that our motive is pure helpfulness. Later, analyzing our
motives, we may separate out the masterful tendency, which was present
all the time and consciously present, but so bound up with the other
motive of helpfulness that it did not attract attention to itself. Now
if our psychology makes us cynics, and leads us to ascribe the whole
motivation of the helpful act to the mastery impulse, and therefore to
regard this as working in the unconscious, we are fully as far from
the truth as when we uncritically assumed that helpfulness was the
only motive operating.

For man, to live means a vast range of activity--more than can
possibly be performed by any single individual. We wish to do a
thousand things that we never can do. We are constantly forced to
limit the field of our activity. Physical incapacity, mental
incapacity, limitations of our environment, conflict between one wish
and another of our own, opposition from other people, and mere lack of
time, compel us to give up many of our wishes. Innumerable wishes must
be laid aside, and some, resisting, have to be forcibly suppressed.
Renunciation is the order of the day, from childhood up to the age
when weakness and weariness supervene upon the zest for action, and
the will to live fades out into readiness to die.

What becomes of the suppressed wishes, we have already briefly
considered. [Footnote: See p. 533.] We have noticed Freud's conception
{567} that they live on "in the unconscious". Nothing ever learned, he
would say, can ever be forgotten, and no wish ever aroused can ever be
quieted, except by being gratified either directly or through some
substitute response. Each one of us, according to this view, carries
around inside of him enough explosive material to blow to bits the
whole social structure in which he lives. It is the suppressed sex
wishes, and spite wishes growing out of thwarted sex wishes, that
mostly constitute the unconscious.

These unconscious wishes, according to Freud, motivate our dreams, our
queer and apparently accidental actions, such as slips of the tongue
and other "mistakes", the yet queerer and much more serious "neurotic
symptoms" that appear in some people, and even a vast deal of our
serious endeavor in life. All the great springs of action are sought
in the unconscious. The biologist, consciously, is driven by his
desire to know the world of plants and animals, but what really
motivates him, on this view, is his childish sex curiosity, thwarted,
driven back upon itself, and finding a substitute outlet in biological
study. And so, in one way or another, with every one of us.

All this seems to depart pretty far from sober reality, and especially
from proved fact. It involves a very forced interpretation of child
life, an interpretation that could never have arisen from a direct
study of children, but which has seemed useful in the psychoanalysis
of maladjusted adults. It is a far cry from the facts that Freud seeks
to explain, to the conception of the infantile unconscious with which
he endeavors to explain them.

Freud's conception of life and its tendencies is much too narrow.
There is not half enough room in his scheme of things for life as it
is willed and lived. There is not room in it even for all the
instincts, nor for the "native likes and dislikes"; and there is still
less room for the will to live, in {568} the sense of the zest for all
forms of activity, each for its own sake as a form of vital activity.
Any scheme of motivation, which traces all behavior back to a few
formulated wishes, is much too abstract, as was illustrated just above
in the case of the helpful act.

Freud is apparently guilty of yet another error, in supposing that any
specific wish, ungratified, lives on as the same, identical, precise
wish. A very simple instance will make clear the point of this
criticism. Suppose that the first time you definitely mastered the
fact that "3 times 7 are 21", it was in a certain schoolroom, with a
certain teacher and a certain group of schoolfellows. You were perhaps
animated at that moment by the desire to secure the approval of that
teacher and to shine before those schoolfellows. Does it follow, then,
that every time you now make use of that bit of the multiplication
table, you are "unconsciously" gratifying that wish of long ago? To
believe that would be to neglect all that we have learned of
"shortcircuiting" and of the "substitute stimulus" generally.
[Footnote: See p. 338.] That wish of long ago played its part in
linking the response to the stimulus, but the linkage became so close
that that precise wish was no longer required. The same response has
been made a thousand times since, with other wishes in the game, and
when the response is made to-day, a new wish is in the game. It is the
same with the biologist. Suppose, for the sake of argument, what
probably is true in only a fraction of the cases, that the biologist's
first interest in making any minute study of animals arose from sex
curiosity. As soon, however, as he engaged in any real study of
animals, substitute stimuli entered and got attached to his exploring
responses; and to suppose that that identical wish of long ago is
still subconsciously active, whenever the biologist takes his
microscope in hand, is to throw out all {569} these substitute stimuli
and their attachments to many new responses, and to see in a very
complex activity only one little element.

In making use of the conception of the unconscious to assist us in
interpreting human conduct, we are thus exposed to two errors. First,
finding a motive which was not analyzed out by the individual, and
which was only vaguely and implicitly conscious, and formulating that
motive in an explicit way, we are then liable to the error of
supposing that the motive must have been explicitly present, not
indeed in consciousness but in the unconscious; whereas the whole
truth is exhausted when we say that it was consciously but only
implicitly present--active, but not active all alone. Second, having
traced out how a certain act was learned, we are apt to suppose that
its history is repeated whenever it is performed afresh--that the
wishes and ideas that were essential to its original performance must
be unconsciously present whenever it is once more
performed--neglecting thus the fact that what is retained and renewed
consists of responses, rather than experiences. What is renewed when a
learned act is performed is not the history of the act, but the act
itself. In a new situation, the act is part of a new performance, and
its motivation is to some degree new.

Though his theories are open to criticism, Freud has made important
contributions to the study of personality. The same can be said of
other schools of psycho-pathology. Jung and Adler deserve mention as
representing varieties of psychoanalysis that differ more or less
radically from that of Freud. Outside of the psychoanalytic school
altogether, Janet and Morton Prince have added much to psychological
knowledge from their studies of dissociated and maladjusted
personalities. In endeavoring to assist the maladjusted individual,
all these schools have much in common, since they all seek to bring to
his attention elements in his personality {570} of which he is not
clearly aware. Clear consciousness of implicit or dissociated elements
in one's personality often proves to be a step towards a firmer
organization of the personality and towards a better adjustment to the
conditions of life.


{571}

EXERCISES

1. Outline the chapter.

2. Mention some personal traits that appear when the individual
   is dealing with inanimate things, and some that only appear in
   dealing with other persons.

3. Construct a "rating scale" for the trait of independence, as
   follows. Think of some one who is extremely independent, and call
   him A; of some one who is at the opposite extreme and call him E;
   of some one standing halfway, and call him C; and fill in the
   positions B and D with other persons standing between A and C and
   between C and E, in this matter of independence. You now have a
   sort of measuring rod, with the five persons A, B, C, D and E
   marking degrees of the trait. To rate any other individual,
   consider where he belongs on this scale--whether even with A, with
   B, etc.

4. How does the embarrassing "self-consciousness" of one who is
   speaking in public differ from simple consciousness of self?

5. Consider what was conscious and what unconscious in the following
   case of "shell shock": A sharpshooter had a certain peekhole in the
   front of the trench through which he was accustomed to take aim at
   the enemy. The enemy evidently spotted him, for bullets began to
   strike close by as soon as ever he got up to shoot. He stood this
   for a time, and then suddenly lost the sight of his right eye,
   which he used in aiming.

6. Explain the difference between unconscious action of the
   dissociated type and of the implicit type.


REFERENCES

For attempts to utilize psychological methods in the study of
personality, see F. L. Wells, _Mental Adjustments_, 1917; also Chapter
11 in Watson's _Psychology_, 1919.

Much interesting psychological material, along with a good deal of
philosophical discussion, is contained in James's chapter on the
"Consciousness of Self" in Vol. I of his _Principles of Psychology_,
1890.

For a discussion of the unconscious, see the symposium on
_Subconscious Phenomena_, 1910, participated in by Muensterberg, Ribot,
Janet, Jastrow, Hart and Prince.

On dissociation, see Morton Prince's _Dissociation of a Personality_.

For Freud's doctrine of the unconscious, see his _Psychopathology of
Everyday Life_, translated by Brill.




INDEX

Abulia, 499, 539-541, 545-546

Accessory sense-apparatus, 192-196, 200

Acquired reactions, 89-90, 94, 99-102, 112-114, 144, 247, 296-829, 399

Adaptation,
  of attention, 247, 260;
  negative, 302-303, 310, 312;
  sensory, 224-225, 447

Adjustment, 72, 78-79, 131, 178, 382, 385, 420, 430, 431, 433

Adler, 569

Adrenal glands, 123-124, 554

Advantage,
  factors of, 245-248, 259, 382;
  law of, 256

Aggressive behavior, 160-161, 164-165

After-images, 226-227, 451-452

Ambiguous figures, 253-254, 425

Analysis,
  of motives, 565-566, 569;
  of sensations, 197, 201, 203, 205-206, 211-212, 230, 233

Anger, 118, 122-123, 125-126, 131-132, 158-159, 163, 300-301, 429-430

Animal behavior, 8-9, 14, 39-40, 76-79, 93-94, 97, 105-107, 109-111,
  116, 121-122, 141, 145, 147, 148, 156, 159, 160, 298, 302-311,
  313-314, 317-320, 436, 463-464

Aphasia, 57-60, 62, 428

Appetite, 125, 126

Applied psychology, 3-4

Apraxia, 57, 63-64, 428

Aptitudes, 101, 288-289, 291, 293

Area,
  auditory, 50, 59-60, 62;
  motor, 50-57;
  olfactory, 62-63;
  somesthetic, 50, 62-63;
  speech, 58-60, 62;
  visual, 50, 53, 62-63

Aristotle, 394, 454

Art, 182-183, 512-516

Assertiveness, _see_ Self-assertion

Association, 366;
  by contiguity, 395-398, 405;
  free, 376-381;
  by similarity, 395-396, 405-408, 519;
  laws of, 389-417;
  controlled, 381-385, 413-414, 417

Association fibers, 56, 416-417, 424

Atrophy through disuse, 349, 390, 415

Attachment of stimulus and response, 25, 34-35, 53-54, 84, 92,
  112, 135, 139, 298-301, 303, 311, 338, 372, 377-379, 390, 392, 394,
  399-412, 414-417, 433

Attention, 244-269, 381, 421, 433

Attitude of attention, 249;
  of thought, 249, 464

Autistic thinking, 508-510

Automatism, 26, 328, 338, 383-384, 433, 525, 563

Autonomic nerves, 124-125

Auto-suggestion, 549

Avoiding reaction, 24-25, 142-144, 305, 310

Axon, 31-38, 51-52, 56, 61, 64, 189-192



Baldwin, 243

Basilar membrane, 196, 234-235

Behavior psychology, 1, 8-9, 18, 21

Bergson, 565

Betts, 388

Big, appeal of the, 515-516

Binet, 272-273

Binet tests, 272-275

Binocular,
  rivalry, 253-254;
  vision, 442-443

Biology, 5;
  liking for, 182

Black, a sensation, 218, 223-224

Blends, 197-199, 202-203, 205-206, 219-220, 232, 301, 424, 500

Bloomfield, 104

Boasting, 169, 495

Book, W. F., 325

Brain, 14-15, 28-30, 49-66, 292-293;
  stem, 29-330, 32, 33, 50

Brown, Warner, 449

Bryan, 321



Cajal, 51, 61, 239

Callosum, 56, 62

Cannon, 136

Carr, 314

Caution, 156, 511

"Censor," 505-506

Central neurone, 37-39

Cerebellum, 29-30, 35, 50, 65

Cerebrum, 29-30, 50-64, 292-293

Character, 529, 555

Child, behavior, 91-92, 94-97, 100-101, 138, 141, 143-144, 147,
  150-159, 162-168, 297-298, 300-301, 303-304, 313-314, 319, 357-358,
  434-435, 437, 445, 481-483, 485-487, 490, 501, 504, 506, 526-527

Choice, 528-535

Cochlea, 192, 195-196, 234-235

Co-conscious, 564

Collecting instinct, 141

Color,
  liking for, 183;
  circle, 207;
  cone, 209;
  pyramid, 209;
  sense, 204-228;
  theories, 220-224;
  tone, 206-207, 213-215;
  triangle, 217;
  zones, 211-212;
  mixing, 214-217

Color-blindness, 209-211

Colored hearing, 376

Combination,
  80, 135, 140, 148, 260-261, 299, 301, 306-308, 311, 323-326, 334,
  479, 519;
  law of, 263-264, 398-417, 431-432, 468

Comparative method, 14-15

Comparison, 466-467

Compensatory movements, 236-238

Complementary colors, 216-217, 227-228

"Complexes," 381

Conditioned reflex, 303-304, 312, 401-402

Cones, 191, 226

Consciousness, 7-8;
  of animals, 8-9;
  degrees of, 172, 265-267, 338, 383-384

Constant error, 447-448

Constitution, native, 91, 92, 98, 271, 289-292

Constructiveness, 154, 482

Contentment, 156-157

Contiguity, association by, 395-398, 405

Contrast, visual, 227-228

Control, 55, 257, 298, 320, 335-336,
  348, 381-385, 413-414, 417, 484, 511

Cooerdination, 30, 37-39, 41, 55-59, 66, 260-261, 299, 410-412, 534-535

Correlation method, 14-16, 283-285

Cortex, 50, 52, 56-63, 293, 414, 423

Counter-suggestion, 549

Cramming, 342, 346

Criteria of instinct, 92, 97, 138

Criticism, 499-500, 503, 505, 508-512, 547

Crying, 144

Curiosity, 154-157, 181, 244, 258

Curve,
  of distribution, 280;
  of forgetting, 350, 390;
  of learning or practice, 307, 316, 321, 325, 390

Cutaneous senses, 197-201, 224, 440, 451



Dallenbach, 362

Daring, 489, 518-519

Darwin, 127, 136

Davenport, 104

Day dreams, 493-499

Decision, 528-535

Defense mechanisms, 533, 535

Defensive reactions, 24-26, 142-144, 159-160, 162-164, 310

Delayed reaction, 76-77, 429

Delusion, 509

Dendrites, 31-32, 34-35, 51, 61, 190, 414

Detachment of response from stimulus, 299, 302, 310, 328

Determining tendency, 72, 380-385

Dewey, 480

Differential psychology, 3, 12, 180, 210, 271, 272, 274, 279-280,
  286, 291-292, 368-370, 374, 548

Digestion, 121-123, 125

Discord, 232

Discovery, 421, 462

Discrimination, 435-437

Disgust, 127, 312

Dissociation, 559-561

Distraction, 259-260, 356-356

Distribution of intelligence, 274-275, 279-281

Dizziness, 238

Domination, 165

Dot figure, 252

Doubt, 472-473

Drainage, 269

Dreams, 499-508



Ear, 191-192, 195-196, 236-238

Ebbinghaus, 350, 365

Economy of effort, 151;
  in memorizing, 338-346, 353

Effect, law of, 391-393, 413

Effort, 127, 162, 259-260, 534, 539

Egocentric response, 380

Elementary,
  feelings, 173, 184-185;
  sensations, 197-198, 201, 203, 211-212, 216-220, 233-234

Elimination in learning, 306, 308-309, 310, 314, 327

Emotion, 118-136, 137-169, 173, 299-301, 345, 355, 361, 381, 513-514,
  554, 661

Empathy, 491, 516-516

Emulation, 165-166

End-brush of an axon, 33-36, 38, 61

Endocrine glands, 122-123, 554

Energy,
  conservation of, 40;
  dammed-up, 82-84, 301, 309, 393;
  released, 535-546;
  stored, 40-41, 46

Envy, 166, 168

Equilibrium, 65

Errors, 446-459, 467

Escape tendency, 142-144, 489, 498-499

Esthetics, 443-444, 457-458

Euphoria, 120, 151

Excitement, 126

Exercise,
  effect of, 297-298;
  law of, 389-391, 393-394, 413-415

Experiment in psychology, 12-15, 93, 302, 333

Explanation, 471-472

Exploration, 154-157, 244, 249-252, 258, 288, 305, 421, 462-465, 470

Expressive movements, 126-128

Eye, 32, 34-35, 62, 191, 198-196;
  movements of, 249-251



Facilitation, 54-55, 78, 83-85, 248, 257, 263, 382-385, 413-414, 417

Factors,
  in attention, 245-248, 259;
  in intelligence, 285-288;
  in memorizing, 345-346;
  in personality, 553-555;
  in recall, 379, 382

Faculties, 523

Fallacy, 467-468, 479

Father complex, 606

Fatigue, 73-74, 119, 123, 145, 151

Fear, 125-126, 129-133, 142-144, 153, 303-304, 489, 497-498, 504,
      513, 516, 539-540;
  abnormal, 133, 497-498

Feeble-mindedness, 275, 290-292, 446

Feeling, 172-185;
  of activity, 45-46;
  of excitement, 126, 184-185;
  of familiarity, 185, 357-360;
  of readiness, 75, 383;
  of tension, 78-79, 184-185

Feeling-tone, 174-176, 178, 180-181

Feleky, 136

Fernald, 388

Fiction, 512-513

Fighting, 158-161

Fissures of the brain, 50

Fixation, 298

Fluctuation of attention, 254-255

Flying, 93

Forgetting, 349-353, 415

Forgotten name, 356, 563-564

Fovea, 193, 211, 226

Free association, 376, 504, 507;
  test, 380

Frequency, 379, 390, 433

Freshmen, intelligence of, 279-281

Freud, 505-508, 522, 566-569, 571



Galton, 368, 388

Gamble, 243

Games, 487

Gates, 339, 365

General psychology, 4-5

Genetic method, 15-16, 90

Genius, 99

Glands, 25, 122-124, 303

Gliding dream, 503

Golden section, 444

Gray matter, 35-36, 50-52, 56, 61-62

Gregariousness, 110, 146-147

Group tests, 276-277



Habit, 89, 112-114, 157, 247-248, 260, 328-329, 381

Hallucination, 375-376, 501, 547

Hart, 571

Harter, 321

Hearing, 50, 59-60, 62, 228-235, 439-440

Helmholtz, 220, 234, 475

Helplessness, 144, 149

Henning, 203, 243

Herd instinct, 110, 146-147

Heredity, 91, 98, 100-101, 118, 289-292

Hering, 220-221

Hero,
  worship, 168;
  conquering and suffering, 494-496, 509

Herrick, 44, 67

Hesitancy, 530

Hicks, 306, 314

Higher units, 323-326, 334, 410-412

Hollingworth, 20, 104, 243

Homing, 78, 146

Humor, theories of, 157-168

Hunger, 79-81, 120, 140-141, 204

Hunter, 88, 295

Hunting instinct, 72, 78, 140-141

Hypnosis, 349, 547-548

Hypothesis, 473-475



Ideomotor action, 527-528

Illusion, 424, 450-459, 500, 547

Imageless thought, 374

Imagery,
  mental, 368-376, 499-500;
  in perception, 425-427;
  types, 370

Imagination, 481-520, 525

Imitation, 319, 486

Impulse, 132-135, 155, 167, 177, 299, 524-525, 539

Incentives, 541-546

Incidental memory, 346-348, 397

Independence, 163-164

Individual, 91

Individual psychology, _see_ Differential psychology

Induction, 374-375

Inference, 465-468, 475-476, 479

Inferiority, sense of, 166, 168, 496, 510, 555

Inheritance of acquired traits, 113-114

Inhibition, 25, 54-55, 78, 83-84, 122-125, 248, 257, 263, 314, 382,
  384, 429-430, 528, 540

Initiative, 545

Insane, 269, 508-609

Insight in learning, 316-320

Instinct, 105-116, 137-169, 179, 181, 488-489, 492, 513, 554;
  criteria of, 92, 97, 138;
  and emotion, 134-135;
  modification of, 299-301

Integration, 558-561

Intelligence, 90-91, 271-293, 538, 555;
  tests of, 3, 272-277, 281-283

Intelligence quotient, 274-275, 289-290

Intensity of sensation, 206;
  of reaction, 379, 391, 433

Interest, 181-184, 248, 257-259

Interference, 355-356

Internal secretions, 122-123, 554

Intra-uterine life, 90-92

Introspection, 10-11, 19

Invalidism, 546

Invention, 421, 475, 484, 485, 509-512, 517, 619

"IQ," 274-275

Isolation, 431-432, 435-437, 455-459, 468,479



James, 117, 129, 136, 331, 365, 418, 480, 511, 551, 561, 571

James-Lange theory, 128-130

Janet, 569, 571

Jastrow, 571

Jennings, 88

Jost, 342

Judd, 461

Judgment, 550

Jung, 388, 569



Kimmins, 522

Kinesthesis, 240

Koenig, 217



Ladd, 44

Ladd-Franklin, 221-224, 243, 453

Lange, 129

Lashley, 88

Laughter, 157-168, 161

Law,
  of advantage, 256;
  of association, 394-398;
  of attention, 256, 262-263, 267;
  of combination, 263-264, 398-417;
  of effect, 391-393;
  of exercise, 389-391, 393-394;
  of habit, 389;
  of reaction, 256, 262-263, 267;
  of selection, 256, 262, 378, 382;
  of shifting, 256, 263;
  of tendency, 81, 263

Learning, 93-94, 96, 99, 112, 113, 143-144, 296-329;
  laws of, 389-417, 433

Libido, 507

Light, 212-213

Likes and dislikes, 178-184, 291, 492-493, 513

Linkage, _see_ Attachment

Lobes of the brain, 50

Local sign, 440-441

Locomotion, 93-97, 99, 152-153, 486

Logic, 475-476

Love, 535

Loyalty, 169, 531



Make-believe, 482-483, 508

Management,
  of action, 541-546;
  of attention, 267-268;
  of memory, 338-346, 353, 356, 360-363;
  of reasoning, 478-479

Manipulation, 154, 315, 481-483

Massed learning, 341-343, 345

Mastery impulse, _see_ Self-assertion

Martin, 28

Mathematics, liking for, 181-182

Mating instinct, 97, 116, 147-148

Maturing, 92, 96

Maury, 501

Maze learning, 305-308, 318-314

McDougall, 136, 171, 418, 551

Meaning, 421, 482-483

Median, 280

Memorizing, 333-346, 360-363

Memory, 332-363

Memory colors, 426

Mental action, 6-7, 45-47

Mental age, 273-274

Mental set, 72, 382-385, 413-414, 417, 433, 452

Mental work, 384

Methods of psychology, 9-16

Mnemonic systems, 363

Modification of reactions, 297-299

Moll, 551

Morale, 543-545

Morgan, 270

Mother complex, 506

Mother instinct, 148-150, 159, 161

Motive, 69, 72, 84-85, 137, 257-258, 469-473, 487-499, 501-510,
  513-517, 528-546, 565-570

Motor,
  area, 50-54;
  centers, 50-59, 65, 66;
  nerve, 27, 30-33, 36-37, 39, 50, 52-53

Movement,
  expressive, 126-128;
  reflex, 24-26;
  skilled, 55-59, 268, 321-326, 410-412;
  voluntary, 53-55, 298

Moving pictures, 454

Mueller-Lyer illusion, 455-456, 459

Muensterberg, 265, 571

Muscle sense, 225, 238-240

Music, 235;
  liking for, 182-183, 291

Music deafness, 60


Native traits, 89-102, 297

Negative adaptation, 302-303, 310, 312, 413

Nerve, 26, 30, 32;
  autonomic, 124-125;
  cell, 31-36, 51, 414;
  center, 26, 29-30, 49-66, 76, 82-84, 96, 107, 125, 293;
  fiber, 32

Nervous system, 27-29, 32, 41, 124

Nesting, 105, 110-112

Neurone, 32-36, 51, 61, 346, 414-417

Newton, 212

Nicoll, 522

Nightmare, 504

Noise, 231, 236

Nonsense syllables, 334

Non-sensory recall, 373-375

Norsworthy, 20, 104, 522



Object blindness, 62

Objective observation in psychology, 9, 11-13

Observation, 267;
  learning by, 317-320, 333-337, 348, 367-375

Obstruction, 162-163, 177, 534-559

Organic needs, responses to, 139-145

Organic sensations, 119-120, 128, 204

Organic state, 72-74, 79, 82, 119-126, 132-133, 175-176

Original nature, 91, 92, 98

Organization of the individual, 527, 529, 532, 558

Otolith, 192, 238

Overlapping, 324-325, 412

Overtones, 230, 438



Pain, 173, 198-201

Paired associates, 336, 347, 404

Paralysis, 57, 547

Parental instinct, 148-150

Parsons, 243

Path,
  auditory, 62;
  motor, 51-53, 62;
  tactile, 62, 64

Pathological method, 16

Patterns, 204-205

Pechstein, 344

Perception, 45, 60, 62-63, 65-66, 419-459, 462, 465, 468, 475-476,
  479, 520

Performance tests, 275-276

Perseveration, 355

Personality, 552-570

Perspective, 435, 441-442, 453-454

Phrenology, 52, 65, 293

Physiognomy, 445-446

Physiological limit, 321

Physiology, 6-7

Physique, 553

Piano theory of hearing, 234-235

Pieron, 342

Pillsbury, 270, 295

Pintner, 295

Pitch, 229-230, 450

Place associations, 304, 305, 315, 333

Plan, 483, 493, 539-540

Plateau, 322

Play, 139, 148, 151-152, 160, 485-499, 504-505, 517

Pleasantness and unpleasantness, 173-180, 184-185

Poffenberger, 20, 104, 243

Poggendorf illusion, 457, 459

Practice, 177, 298, 304-310, 314-317, 321-327, 360-363, 433, 538;
  curve, 307, 316, 321, 325, 390, 542

Preparation for action, 22-25, 72, 74-77, 427-430

Preparatory reactions, 77-84, 111-112, 125-128, 132, 139-140, 145, 147

Prestige, 549

Prince, 559, 564, 569, 571

Problem solution, 385, 465, 469-470, 477, 514

Proofreader's illusion, 453

Protozoa, 39-40, 188, 302

Psychiatry, 16

Psychoanalysis, 505-508, 521, 533, 567-669

Psychology,
  definition of, 1-2, 5-8, 17-18;
  methods of, 9-16;
  varieties, 2-6

Psychopathology, 16, 498, 540-541, 545-550, 567, 569

Punishment, 304-305

Purpose, 69-71, 75, 78, 524-527, 542

Puzzle experiment, 308-310, 315-319, 463-464

Pyle, 343

Pyramid cells, 51, 52, 61

Pyramidal tract, 52-55, 57, 62



Random activity, 151-152

Rationalization, 470-471, 531

Raynor, 331

Reaction, 22-26, 39-41, 45-49, 65-66, 68, 75, 84, 256, 262-263, 266,
  423, 428;
  acquired, 89-90, 94, 99-102;
  delayed, 76-77, 429;
  native, 89-102;
  preparatory, 77-84, 111-112, 125-128, 132;
  time, 22-24, 75, 424

Reading, 250-251, 258, 262, 267-268, 384, 427, 453, 512-513

Reaney, 522

Reasoning, 320, 422, 462-479, 520;
  in animals, 310, 317-318, 463-464

Recall, 354-356, 366-385, 413, 422, 469-471, 500, 519, 563

Recency, 345, 356, 379, 390, 433, 511, 563

Recitation in memorizing, 339-341

Recognition, 187, 357-360

Red-green blindness, 210

Reflex, 24-26, 53, 107-109, 256, 297;
  conditioned, 303-304;
  control of, 54-55;
  arc, 26-30, 34, 36-37;
  centers, 30, 53

Relationships, response to, 286-287, 317, 320, 333-336, 345, 404-405,
432, 467-468, 520

Relief, 79, 84

Reproduction, instinct of, 116

Respiration, 37, 55, 141, 176, 527

Response by analogy, 405-406, 435, 452-455

Restlessness, 78-79, 112

Retention, 286, 302, 349-353, 360, 562

Retina, 191, 193, 195, 210-211, 233, 441-442

Revery, 376-380

Ribot, 571

Rivalry, 165-166, 474, 489, 543;
  binocular, 253-254

Robinson, 522

Rods, 191, 226

Rotation, sense of, 236-238

Rosanoff, 20

Rote learning, 333, 337

Royce, 522

Ruger, 316


Sanford, 252

Satisfaction, 79, 84, 109-110, 132, 472, 487-499, 501-510, 513-517,
  533-535, 540

Saturation of colors, 207-208, 213-214, 217

Scatter, 23, 273, 298, 448

Schopenhauer, 565

Science, 3-4, 473-475;
  liking for, 181-182

Scott, 93, 551

Seashore, 295

Secondary personality, 559-561, 564

Selection, 256, 262. 378, 382

Self, 428, 555-558

Self-activity, 46-47

Self-assertion, 158, 161-169, 181, 183, 258-259, 287, 472-478,
  489-496, 502-503, 508, 513, 515-516, 531, 536-537, 545-546, 549,
  556-558

Self-criticism, 509-511

Selfishness, 557

Self-preservation, 115-116, 507

Semicircular canal, 192, 194, 195, 225, 236-238, 486

Sensation, 6, 19, 46, 60, 62-64, 120, 187-240;
  and feeling, 173-174;
  feeling-tone of, 174-175;
  and perception, 423-425;
  recall of, 368-376

Sense, cells, 189-192;
  organs, 188-196, 199-200, 236-239, 249;
  perception, 421-422

Sensory,
  nerve, 27, 30, 32-34, 36-38, 188-189, 191, 193, 196, 239-240;
  areas, 50, 59-66, 423

Setting of an object, 358

Sex,
  attraction, 97, 116, 125, 147-148, 488, 507-508, 534-535;
  differences, 281

Sex differences, 281

Shame, 166, 168

Shell shock, 504

Shifting of attention, 251-256

Short-circuiting in the process of learning, 338, 405, 568

Shyness, 166

Sight, 32, 34-35, 62, 191, 193-195, 204-228, 231-234, 441-443

Sign and meaning, 421, 437-446

Signal experiment, 304-305, 312

Similarity, association by, 395-396, 405-408

Size-weight illusion, 459-460

Skill, 55-59, 268, 282, 348, 352, 410-412, 428, 482, 488

Skin senses, 197-201, 224, 440, 451

Sleep, 145, 499-500

Smell, 29, 32, 62, 63, 190, 201, 203-204, 224

Snyder, 343

Sociability, 181, 183-184, 489, 492

Social, behavior, 145-151, 510. 552, 558-559;
  perception, 444-446, 512, 555

Sociology, 5

Song of birds, 98-94

Sound, 228-231

Space, 439-443

Spaced repetition In learning, 341-343, 345, 390

Spaulding, 93

Span of attention, 261-262

Speech, 6, 60, 94, 98, 113, 154, 325, 402-403, 416;
  centers, 57-62

Spinal cord, 29-33, 50, 52, 55, 64

Spite, 507

Staircase figure, 253

Starch, Daniel, 20, 331

Starr, 56

Statistical measures, 14-15, 280, 283-285

Stereoscope, 254, 442

Stiles, 44, 67

Stimulus, 22, 24, 26-27, 34, 40-41, 46-49, 188, 484-486, 500-501;
  central, 48-49, 368, 371, 422, 468, 500, 528;
  internal, 41, 47, 79, 119, 128, 132

Story-telling, 482-483

Straining, 162-163

Strong, 246, 351

Struggle for existence, 114

Subconscious minds, 563-564

Sublimation, 533-535

Submissive tendency, 166-169, 287, 516, 549

Substitute, response, 299-301, 305, 311, 328, 400, 409-413, 430,
                      436-437, 498-499, 533;
  stimulus, 298, 300, 303, 311, 368, 371-372, 376, 400-409, 416, 434, 568

Suggestion, 546-650

Suppression, 505-508, 533, 566-567

Surprise, 155

Survival value, 114, 139, 148, 151, 160

Survivals, 127

Sustained attention, 257-260

Syllogism, 476-479

Symbols, 383, 468, 505-507

Symmetry, 444

Synapse, 34-35, 96, 414-416

Synesthesia, 376



Tact, 555

Taste, 189-190, 201-208, 224

Taussig, 522

Telegraphy, learning of, 321-323

Temperament, 553-554

Temperature, responses, 141-142;
  sense, 197-201, 224-225

Tendency, 68-85, 109-112, 116, 130-135, 137-169, 177, 257, 263,
  299-301, 309, 348, 367, 382, 392-393, 408-409, 417, 483-499,
  501-510, 512-516, 528-546, 561

Terman, 272, 296

Testimony, 347, 352, 397

Tests, 3, 12, 14, 272-277, 281-283, 548

Thalamus, 56, 62, 64-65, 178

Thinking, 48-49, 319-320

Third dimension, 441-443

Thirst, 79-81, 120-121, 139-140, 179

Thorndike, 20, 104, 171, 331, 418

Thought and action, 539-541

Thrill, 489, 498-499

Thyroid gland, 123, 554

Timbre, 231

Time, 438-439, 447

Titchener, 186, 242, 270, 461

Touch, 50, 62, 63, 197-201;
  spots, 198

Toys, 486-497

Training of memory, 360-363

Traits, native and acquired, 89-102

Transfer, 316-317, 361-362

Trial and error, 112, 305, 309, 311, 313, 315, 335, 392, 409, 424, 426,
  430, 462-465, 526

Typewriting, learning of, 324-325, 411-412, 518, 525-526, 537



Unconscious, activity, 265-266, 383-384, 506-508, 525-526, 562-565;
  emotion, 118-119;
  feeling, 172;
  motive, 565-569;
  retention, 348-349, 562

Unintentional learning, 346-348

Utility,
  of emotion, 125-127;
  of instinct, 114, 144-145;
  of reflexes, 125


Vacillation, 530

Variability, 23, 273, 298, 369, 447-448

Verification of hypotheses, 473-475

Visual,
  area, 62;
  images, 370;
  perception, 441-443, 450;
  sensations, 204-228, 231-234

Visualist, 370

Vocalization, 93-94, 154

Voluntary action, 298, 524-528

Vowels, 231


Walking, 95-97, 99, 153

Warming-up, 74, 119-120, 343, 391

Warren, 171, 242, 418, 461

Washburn, 19, 88, 331

Watson, 20, 88, 117, 171, 307, 308, 331, 571

Watt, 243

Weber's law, 449-450

Weight, perception of, 448-450, 459-460

Wells, 571

Whipple, 295, 365

White matter, 32, 35-36, 56, 62

Whitley, 20, 104, 522

Whole and part study, 343-346

Will, 523-550;
  to learn, 346-348;
  to live, 565

Wish, 496-497, 501-509, 565

Word
  blindness, 62;
  deafness, 59

Worry, 497-499

Wundt, 184


Yerkes, 104, 295


Young, 220

Youth, 147, 164, 495, 519


Zoellner illusion, 459





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