An introduction to psychology

Preface

Shortly after the appearance of my Psychology in L 1904 ^ I began to receive requests from teachers to pre- '^, pare a briefer volume on the same general lines. This I "p finally agreed to do, but fulfilment has lagged so far be- \j3 hind promise, that despite the continued popularity of the older work, it seems no longer appropriate to attempt a mere digest of it. The present book accordingly represents an entirely fresh survey of the field, and attempts to set forth simply and concisely the more important principles of general psychology. Some comment upon the relation of the two books to one another may be of interest. The prompt welcome accorded the earlier work was presumably due to the novelty of certain of its features, which have since been adopted in greater or less degree by other authors. It emphasized for the first time, so far as I am aware, the distinction between structural and functional methods in psychology. It adopted and consistently utilized an essentially biological point of view in its interpretation of mental life, this position being reflected in part in the arrangement of the topics to exhibit the progressive stages of adjustment. It presented, provisionally to be sure, a definite and teachable system, which gave students who mastered it a sense of control over the material, enabled them to observe and think psychologically for themselves and — not least important — afforded them a terminology and a point of view which rendered the litera-

^ Fourth edition, 1908.

iii iv PREFACE

ture of the subject easily accessible. Such changes as appear in the present text simply reflect alterations of emphasis and points of view which the development of the science has rendered necessary.

The structure-function distinction still seems to me significant. But it is no longer a matter of acute controversy and so requires a less militant treatment. Polemic is now centered about the ' behavioristic ' movement, which, with its gospel of objective methods and its crusade against introspection, presents an interesting blend of solid contribution and adolescent exaggeration. Whatever seems to me to be sound in its position, I have adopted. It lends itself readily to incorporation into the biological conception of mental activity, which I have retained and energetically pressed.

The organizing character of every level of our psycho-motor activities is more explicitly brought out than in the older book, with advantage, I trust, to the depth and vividness of impression left on the reader's mind regarding "the real nature of our adjustments to environment.

I have come in recent years to assign more importance than I formerly did to the function of subconscious processes in our behavior. I do not for a moment accept the prurient implications of much of the Freudian doctrine, nor have I been greatly influenced by any of its contentions; but on other grounds I have come to the belief that there is a large element of intrinsically intelligent control in many neural processes which escape our direct conscious observation. This I hold to be as true of reflective thought as of the more overt control of our muscles. The text will be found to reflect something of this conviction.

PREFACE V

My views on the function of imagery have been a good deal misunderstood. This is hardly the place in which to confront my critics, but I trust that the present text may be found less open to misapprehension. With the recently developed doctrine of 'imageless thought' I am warmly sympathetic so far as it has served to direct attention to the meaning aspect of our mental operations, in distinction from their mere sensuous texture. Much of its pretense to novelty I think is based on the misconstruction of earlier doctrine. Its postulate of the existence of states of consciousness wholly devoid of sensorial or imaginal factors I regard as altogether unsubstantiated.

After extended conferences with teachers I have decided to omit any practical exercises. In the first place I find that many instructors prefer to prepare their own; and in the second place there are now a number of admirable manuals written to supply this precise need. I consider such exercises an essentially indispensable part of a wellrounded introductory course, but they need not be made dependent on the teachings of any particular text.

For the use of a number of illustrations acknowledgments are due to the following authors and publishers : D. Appleton & Co., publishers of Barker's ''The Nervous System"; Ginn & Co., publishers of ''The Elements of Physiology" by T. Hough and W. T. Sedgwick ; John Murray, publisher of "The Physiology of the Sense Organs" by McKendrick and Snodgrass; G. P. Putnam's Sons, publishers of Loeb's "Physiology of the Brain"; W. B. Saunders & Co., publishers of Howell's "Text-Book of Physiology"; and Walter Scott, Ltd., publishers of Donaldson's "Growth of the Brain."

vi PREFACE

I am under many obligations to my former students and to my colleagues at the University of Chicago for suggestions and criticism. My wife has aided me greatly in the preparation of my manuscript.

J. R. A.

Chicago, May 1, 1918.

Contents

CHAPTER PAGE

I Problems and Methods of Psychology . 1

II Inherited and Acquired Behavior . . 10

Chapter I Problems And Methods Of Psychology

The Subject Matter of Psychology. — Old and well established sciences generally feel it unnecessary to define themselves for the benefit of the beginner. Young sciences, on the other hand, commonly seek to make cl^ar the field which they propose to occupy. To the beginner, any definition of a science must be somewhat vague and formal, because he cannot intelligently interpret its real meaning in advance of a knowledge of the facts with which the science deals. We shall therefore make no serious effort at this point to construct a precise definition of psychology, which is the" youngest of the biological sciences. It is, however, possible to give rough indications of a helpful kind regarding the general character of the problems to be confronted.

The older definitions of psychology spoke of it as 'the science of the soul,' and this designation was long employed and only abandoned at last because of the many confusing implications of the word soul. Then followed a period when psychology was described as 'the science of mind.' In its turn the word mind in this definition was abandoned in favor of the term 'consciousness.' In each case a more general and less compromising term was substituted for one about which there had gathered a group of irrelevant or misleading associations. Consciousness itself has now fallen victim to the same movement, and in its place we are urged to use such terms as 'behavior/ 'conduct,' or 'intelligence.'

At this juncture it is far less important to secure a verbally precise and accurate definition than it is to gain a fruitful working idea of the general range of facts with which psychology deals, and the technique by which it gathers, organizes, and interprets these facts. Broadly speaking, then, the psychologist's subject matter concer^ns thinking, feeling, and acting. When psychology is defined, as often occurs today, as the science of heJiavior, it is to be understood that the term behavior includes these three processes.^ We shall try in this book to point out what are the materials of which intelligence is composed, what the conditions under which it arises, what the purposes for which it is employed, and what the manner in which conduct is controlled. The attempt to unravel all the strands which are twisted together in this skein of life will take us into the study of many facts seemingly remote from those which we thus set out to explore.

Physiological and Social Conditions of Human Experience. — In the first place, all life is built upon physical and physiological foundations. It is quite impossible to understand human nature, even in a common-sense way, without a knowledge of the bodily structure of the human being. Much less can one pretend to scientific knowledge without recourse to physiological materials. We shall therefore find it frequently necessary to employ informa-

* A few advocates of ' objective psychology ' or ' pure behaviorism ' would wholly disregard thinking and feeling, devoting their entire attention to a study of motor activity.

PROBLEMS AND METHODS OF PSYCHOLOGY 3

tion about the body, and particularly about the brain and nervous system.

Again, all life to some extent, and especially human life, is lived among social surroundings. It is idle to attempt to understand human behavior without constant regard to these social relations. Our modern science has taught us to see all contemporary conditions in the light of their evolution from the past. These social conditions quite as truly as those of a physiological kind are today interpreted from the point of view of development and adjustment. Life has always been a process of adapting the organism to the physical conditions of climate and food supply on the one hand, and to social organization on the other. The conduct of man today reflects the racelong history of struggle and adjustment in each of these directions, and to understand any piece of behavior involves taking into account to some extent influences which point backward to this illimitable racial past.

Methods of Gathering Facts in Psychology. — There is in progress at present a very vigorous controversy as to the correct method in psychology. The traditional one upon which all the early accomplishments of psychology rest is known as introspection. It consists in the direct systematic process of self-observation. I ask myself to recall what I was doing yesterday at this hour, and immediately after bringing into mind the events in question, I try to discern and describe the particular manner in which the occurrences are portrayed in my thought. I may, for example, in my 'mind's eye' see myself walking to my office. Evidently such a method is at the disposal of anyone who chooses to employ it. It is purely observational, differing from the usual forms of external observation in having one's own internal mental operations as its object, rather than the facts and events of the outside world.

A good deal of mystery has at times been attached to this introspective process, and unmeasured criticism has been directed at it, ranging all the way from a denial of its possibility on the ground that a mental state cannot observe itself while it is going on, down to the less sweeping but more pertinent criticism, that the method is prone to many forms of error which are extremely difficult to control. The merits of this controversy can hardly be entered upon here. Suffice it to say that direct observation of the kind described, i.e., of mental experiences just past, is a commonplace of everyday life, and that, carried out carefully and systematically by many individuals, it has resulted in the accumulation of a very respectable body of knowledge entirely worthy of the term scientific.

Over against introspection or subjective observation, is the general method of objective observation, which is essentially that employed in all the physical sciences. The defenders of the latter urge that it is the only really scientific method, because it is the only one affording unequivocal opportunity for verification of alleged facts and events by more than one observer. Needless to say, chemistry, physics, geology, and the biological sciences in general are based entirely upon this method. As applied to psychology, it necessarily involves the attempt to use the external bodily expressions (e.g., gestures, words, facial movements, etc.) as a basis for the understanding of behavior, and its advocates maintain that one can accurately describe and measure the significant facts of mental activity just in the degree in whi^h one can determine its

PROBLEMS AND METHODS OF PSYCHOLOGY 5

external manifestations. All else, they say, is elusive, and purely subjective and incapable of scientific treatment.

The fact that mental states do ultimately secure expression in conduct need not be questioned; nor is anyone likely to doubt that many states of mind, such for example as anger or embarrassment, may be reflected immediately and unequivocally in facial expression. But there is also no reason to call in question the fact that at present, at least, our ability to detect accurately the external expressions of the great majority of our mental states lags far behind our ability introspectively to describe and analyze them. Who can say from observing my external appearance whether I am thinking about Napoleon or Julius Caesar? It seems, therefore, to be the part of common sense to avoid the extremism of the partisans in this controversy. Let us recognize that wherever possible, it is highly desirable to make use of the bodily expressions of mental states, because of their tangible objective character; but wherever this is impossible, as is at present the case in many regions of mental life, let us rely upon trained scientific introspection.

Scientific Organization of Data. — It should be clearly understood that both of these methods to which reference has just been made have to do with the gathering of data, the collecting of the facts of intelligent behavior. This process is the first step in any science, but it is only the first. There then remains the task of analyzing and organizing the facts, of classifying them in ways which will exhibit their relations to one another and make them intelligible in their entirety. Moreover, wherever this is practicable, a modern science, in addition to trying thus to analyze and describe, attempts to explain. Analysis, organization, explanation, the ability to predict events because of the knowledge of the relations of cause and effect in a given group of phenomena — these are the characteristics of every established natural science.

Experiment in Psychology. — Quite the most important modern advance in psychology is to be connected with the development, in the middle of the last century, of the experimental movement. Progress in the other natural sciences has been rapid directly in proportion to their development of experimental technique. An experiment is an observation made under conditions of control. It gains its crucial importance from the fact that it permits an exact repetition of conditions, and thus makes possible verification by many observers of whatever facts are reported. It had always been supposed that mind w^as excluded from experimental attack because the necessary control could not be secured. Thanks largely to the work of Weber, Fechner, and Wundt, the possibility of psychological experiment has been forever put beyond the pale of doubt. While some mental processes are more resistant than others to experimental approach, there is hardly any significant group of mental operations which has been found entirely obdurate. By far the greater portion of our mental life has been already to some extent explored by experimental methods.

Experiment has shown itself fruitful both in the range of introspection and in that of objective observation. In the one case, the experimental situation is so devised as to assist introspective analysis, and to permit the reinstatement time after time of substantially the same mental conditions. After-images of color may thus be studied by repeating the stimulus again and again. In the case

PROBLEMS AND METHODS OF PSYCHOLOGY 7

of direct observation, the experiment is designed to elicit modes of behavior which can be observed and recorded by the experimenter. The promptness of a movement made in response to a sound, for example, can thus be determined by time-measuring apparatus. Although both types of observation are thus involved in experimental procedure, it is probably fair to say that the objective type is tending on the whole to displace the other.

The Different Fields of Psychology. — In the present text we shall be chiefly concerned with the facts involved in ordinary human behavior. This field is commonly designated general psychology. It has to do with the typical forms of behavior characterizing the normal adult. There are, however, other important divisions of psychology which we shall invade from time to time in order to secure useful material. The mental life of children has been rather extensively studied, and constitutes a reasonably distinct branch of investigation, sometimes called child psychology, sometimes genetic psychology. Similarly the study of mental abnormalities constitutes another subdivision generally spoken of as abnormal psychology. Despite the fact that all mental life of human beings is lived amid social surroundings, and that it is quite impossible to understand human behavior without regard to influences which arise from these relations, it has been found profitable to create a special division known as social psychology. In this field attention is particularly directed to a study of the explicitly social instincts and attributes of the mind, and to an analysis of the mental factors in social organizations and institutions. Eace psychology is an older division of the subject, devoted to the attempt to ascertain and describe those peculiarities of temperament and behavior which ostensibly characterize different races. Variational psychology, or individual psychology, concerns itself with the study of those personal idiosyncrasies of temperament, taste, intellectual capacity, etc., which mark off one human being from another. Much of the most interesting and significant addition to our psychological knowledge has in recent years come from the study of animal behavior. To this field is generally applied the term animal psychology, or sometimes the term comparative psychology.

There is a branch of psychology known as physiological psychology which has historically grown up side by side with experiment, and made incessant use of experimental procedure. Strictly speaking, it ought perhaps to be regarded as a special psychological field. It is often spoken of as though it w^ere a definite method. However it may be classified, it consists as a matter of fact simply in the attempt systematically to study mental life in connection with bodily processes, particularly those of the brain and nervous system. We shall have frequent occasion to make use of its materials.

Psychophysics is a name applied to a branch of psychology developed by the German scientist, Fechner. It has led to the development of quantitative psychology, which is concerned with the attempt to measure mental processes. We shall have relatively little to do with this division of psychological inquiry.

Psychology and Other Sciences. — In advance of any detailed knowledge of psychology, it is hardly profitable to dwell upon its relations to other natural sciences. Suffice it to say that like them, it has historically developed out of philosophy, with which it still retains rather more

PROBLEMS AND METHODS OF PSYCHOLOGY 9

intimate relations than do those sciences, e.g., physics and chemistry, which separated themselves from the parent (philosophical) stem at an earlier time. As a science psychology may fairly claim a place in the biological group, because its subject matter is life in certain of its expressions. The intimacy of the relationship is in a measure attested by the extent to which psychology conceives of its problems in evolutionary terms and in terms of the adjustment of the organism to physical and social environment.

Like other sciences, psychology has both a pure and an applied aspect. In its applications, it stands closely related to education, to medicine, to jurisprudence, and to many of the professional and practical interests of life. These applications are still in their early infancy, and, although extremely interesting and valuable, must presumably wait for any approach to completeness upon a far higher development of the pure science. It is fair to add that they are themselves making genuine and important contributions to this pure science.

Chapter II Inherited And Acquired Behavior

It will perhaps assist us if, before proceeding to a detailed study of behavior, we pass rapidly in review some of its chief forms. This will give us a rough working idea of the path which we are to follow in our more exact analysis.

Classification of the Forms of Behavior. — For practical purposes we classify behavior in many different ways. We speak of it as good or bad, as kind or cruel, as thoughtful, stupid, or clever. Evidently such divisions are designed to mark certain moral or intellectual qualities which we think of as attaching to it. Again, we may classify from the point of view of the special kind of action involved, e.g., work or play. Walking, speaking, writing, skating, golfing, playing the piano, are all modes of behavior which might be thus distinguished.

For our present purposes the most useful classification and the one which we should keep constantly in view, will be that which distinguishes innate, inherited, and ^7^- stinctive forms of behavior from those which are acquired, and we may profitably proceed to a brief description of these two types.

Instinctive forms of action are such as the nest-building activities of birds and insects, the seasonal migrations of fishes, birds, and certain mammals, the homing habits of pigeons and certain marine birds. All these forms of

INHERITED AND ACQUIRED BEHAVIOR 11

behavior have in common this native inborn character and their fitness to achieve certain ends necessary to the preservation of the animal or the species. However much an animal may be influenced by the example set by others of its kind, it is quite capable of executing these instinctive acts wholly without tuition. In this sense they are entirely native, and not learned.

Although popular conception does not always recognize this fact, it is nevertheless true that man himself possesses many of these innate forms of behavior. The trembling of the limbs, the blanching of the face, the dryness of the mouth, the nausea and faintness of terror, are instinctive modes of behavior, natural to every child and carried out quite without regard to either precept or example. Similarly the clenching of the fist in anger, the flushing of the skin in embarrassment, the shedding of tears in sorrow or in rage, are all indigenous modes of behavior, inborn in every human being. These activities, like those cited from animal behavior, are all designed to secure some end essential to the welfare of the individual or the race.

Some of the expressions of this character called reflex acts are very simple and are called forth by relatively simple situations. For example, the contraction of the iris in the presence of strong light is a relatively simple muscular movement made in response to the single stimulus, light. The act of coughing is similarly a rather simple muscular response to irritation in the throat. Evidently the incentive to the instinctive response in embarrassment is somewhat more complex. It involves the apprehension of an entire situation, instead of the mere sensing of a single stimulation like light or irritation of the membranes of the throat. There is a very large groupof these innate forms of behavior of which ordinarily we are wholly unconscious. All the great life-sustaining bodily operations are of this character. The beating of the heart goes on for the most part entirely without attracting our notice. The normal processes of digestion are similarly unconscious. Even our breathing rarely intrudes itself upon attention.

It is clear, then, upon the most cursory observation, that the human being comes into the world already provided with an amazing number of muscular capacities at his disposal. The maintenance of life is from the very first dependent upon the proper operation of these inherited activities. As we shall later see, these instinctive traits constitute the foundation upon which are erected all the acquired modes of behavior which we shall presently study.

Acquired Behavior. — As was suggested in the last sentence, the acquired forms of behavior rest upon the instinctive types, but they nevertheless represent quite a different order of affairs. Nobody is born with the ability forthwith to play the violin or to use the typewriter. Both achievements require long practice and painstaking effort. Speech and walking both have an instinctive basis, to be sure, but both require an extended period of learning before they are at all perfect or complete. Practically all our dexterities and acts of skill are of this character. The putting on and off of our clothing, the manipulation of the common utensils of daily life, our social deportment — expressive of the conventional etiquette of our own time, civilization, and set — our enunciation, our professional habits, even in large measure our moral and religious practices and beliefs, are of this acquired character.

As we shall discover at a later point with more detail,

INHERITED AND ACQUIRED BEHAVIOR 13

these acquired acts have all become established as the result of processes in which the mind has played a decidedly conspicuous part. In this regard they are essentially different from the instinctive modes of behavior. Of these latter we may indeed be aware, but they do not owe their peculiar form to any thought which we have accorded them. As they were born in us, so they appear. Obviously the execution of the elaborate conventional social forms peculiar to every civilization involves careful tutelage and a distinct conscious effort of acquirement. The gestures proper to the greeting of a lady by a gentleman in Western Europe are not to be learned without studious effort. Similarly the behavior appropriate to the participant in a ritualistic service involves a prolonged apprenticeship before it can be successfully mastered.

Acquired Acts Become Automatic. — All these illustrations suggest what is a fundamental truth later to be more fully explored, i.e., that many acts which require in their early stages alert conscious supervision, become after a time essentially automatic and take care of themselves; that is to say, they tend to simulate the instinctive and innate forms of behavior. As a child, it requires a long and tedious course of training to master the niceties of table etiquette. But once this is thoroughly learned, it practically cares for itself; and the same thing is true of all the other acquired types of behavior. It is surprising to find how large a part of the behavior of one's working day is of this automatized, habitual kind, and how little of it involves immediate, thoughtful supervision. This is but another way of saying that we are creatures of routine. It involves, however, explicit emphasis upon the fact often unappreciated, to-wit, that well-established routine demands very little active mental control.

Instinctive Behavior in Animals. — As we have already intimated, the modern evolutionary conception teaches that those types of reaction which are effective in maintaining the life of the species inevitably tend to become fixed and to be perpetuated. Nature, it is said, cares nothing for the individual, but everything for the species, and while this is no doubt an overstatement of the truth, there are instances, particularly in insect forms, where the individual sacrifices its life in the act which creates the new generation. It is certainly true, however, that no mode of behavior can hope for survival which stands opposed to the successful maintenance of the species. The great body, then, of instinctive forms of behavior represents types of reaction which have been found useful in the past for the preservation of the species. Many of these, in the nature of the case, must make for the safeguarding of the individual as well. But as we pass upward in our survey of the animal forms from the lower to the higher, we find increasing opportunities for individualistic types of adjustment, and it is in this region of adaptive behavior that we encounter the group of actions which we have called acquired. They, too, are broadly preservative in character, but they represent the region of unstable and incomplete adjustment. The individual tries out for himself a new line of action, which may prove a success or a failure.

The simplest type of the known animals is represented by amoeba. The amoeba is an almost structureless speck of jelly-like protoplasm. Under the microscope it can be seen to consist of a nucleus surrounded by fluid protoplasm. This little organism secures its food by gradually envelop-

INHERITED AND ACQUIRED BEHAVIOR 15

ing it with its liquid surfaces. If it be attacked by strong acids, or similar stimuli, the protoplasm tends to flow away from the source of attack. Its reactions are therefore confined to these simple activities of approach and retreat, with the assimilation of food and the rejection of waste products, all functions of this one simple cell-like structure. Evidently the scope of adjustive activities for such a creature is extremely limited.

Passing to a much higher order of animal life, such as is represented by the fishes, we find again that the main forms of adaptive behavior have to do (1) with the securing of food; (2) with the escape from harmful objects, including both animal enemies and unfavorable physical surroundings, e.g., water which is too cold, too salt, etc.; and (3) with the propagation of the species. In the amoeba, this latter function is brought about by a mere division of the parent cell. In addition to the commoner modes of instinctive expression in connection with the functions which we have listed, fishes, and particularly birds, display the most amazing migratory adjustments, designed to afford them favorable surroundings for the several stages of their life cycle. Practically all our common birds migrate annually over considerable ranges of territory, and some of them journey from the northern end of North America to the extreme southern end of South America.

To adjusting activities of the kinds described, the more intelligent mammals (to say nothing of the fishes and birds) add many types of gregarious instincts, which often safeguard the members of the group from their common enemies. In some cases this community action has an aggressive rather than a merely protective character. Wolves, for example, hunt in packs, as do some other forms of wild animals. Buffalo, deer, and domestic cattle live by preference in herds whose numbers to some extent protect them from the assaults of their enemies. In such group association they benefit by the leadership of the stronger and more intelligent members of the herd.