The fundamentals of psychology

Front matter

Class. " Dr"/3

Book lEo.

GopyrigMlJ". ill

Preface To The Revised Edition

In the present revision I have made numerous changes in expression, have modified several sections that proved unnecessarily difficult for students, and have brought the subject matter up to date. The major changes consist in the introduction of three entirely new chapters. One of these considers the differences in individuals at birth, and presents the methods of measuring intelligence, and the hereditary conditioning of intelHgence. This chapter also gives a preliminary discussion of the laws of learning. To complete the discussion of the innate differences, the chapter on Instinct has been brought forward from the latter part of the book. The two other new chapters discuss respectively Imagination and Dreams, with some reference to Freud, and Fatigue and Sleep.

In the revision I have been much aided by suggestions from teachers in many institutions who have used the book, and especially by my colleagues and Dr. A. H. Sutherland. I desire to express my thanks to all of them named and unnamed.

W. B. PILLSBURY.

Ann Arbor, Michigan, August, 1922.

Digitized by tine Internet Arcinive in 2011 with funding from Tine Library of Congress

Preface To The First Edition

This book is intended to fill a gap which exists to-day between the smaller texts and the reference hand-books. I have had in mind the needs of one of my own classes which devotes a year to psychology and includes students who have had no previous work in the subject. They have more than time to cover the present texts but are lost in the details of the larger works, particularly in connection with the nervous system, sensation, and perception.

I have written for the student primarily and have not presupposed any preliminary knowledge. I have particularly avoided reference to current theories before they are explained and have indulged in no arguments on controversial matter for the benefit of colleagues rather than of the student. Opposing theories are discussed only as they may illumine statements of fact or where they have great historical importance and then only if the problem is real but is not settled.

The technical psychologist may miss long discussions of general method and points of view I have replaced them by fuller statements of the results of experiment and more detailed treatment of the generally accepted body of facts. I have drawn upon the work of all schools without reference to the theories that the workers held, and have stated the results in terms that seemed most suitable to the particular material. Sensation and perception are discussed in structural terms, action of all sorts in behavioristic terms. This gives some inconsistencies, but they are preferable to the viii PREFACE TO THE FIRST EDITION

awkward phrases that would result from using the terminology of any school to the exclusion of the others.

My own theory incHnes. towards a functionalism. The book is more concerned with what consciousness does than with what it is. As opposed to the extreme behaviorism, however, I am not concerned alone with understanding the movements of the organism and the function of the movements, but also with understanding knowledge and the way in which it develops. It is my belief that the content of the science is the same whatever the point of view from which the subject be approached, and that this content is essential and changes slowly and then through growth. The theories are less important and likely to change from decade to decade. In contrast with some of the recent authors I have endeavored to supply the content and, while I have stated my own theories in some detail, have attempted to be sufficiently undogmatic to give the instructor opportunity to develop his own point of view.

I take pleasure in acknowledging the help that has been given in the preparation of the manuscript by Dr. Adams, Miss Perkins, and my wife. All have read the manuscript or portions of it and have made numerous suggestions. The latter has also aided with proofs and index. Dr. Huber has aided much in the selection of illustrations for the neurological portions, and at his suggestion Mr. Atwell of his laboratory has drawn sections for Figures 19, 21, 23, 24, 25, and 26. I express my gratitude to both.

I also desire to thank the individuals and pubUshers who have permitted me to reproduce cuts: Professor Jennings for cuts from his "Behavior of Lower Organisms," Dr. Barker for illustrations from his "Nervous System," W. B. Saunders & Co. for figures from Howell's "Text-book of Physiology" and Huber's "Histology," to Rebmann Bros.

PREFACE TO THE FIRST EDITION ix

for cuts from Bing's "Regional Diagnosis," and to The Macmillan Co. for cuts from Titchener's "Text-book of Psychology," from Thorndike's "Animal Mind," and Foster's "Physiology."

W. B. PiLLSBURY.

Ann Arbor, Michigan, April 25, 1916.

Table Of Contents

Chapter Page

I. INTRODUCTION i

Nature of Psychology 2

Chapter I Introduction

It is easier to say what psychology discusses and to point out the ends of its discussions than to give a formal definition. Psychology is the science which deals with the activities commonly known as mental, the processes of perceiving, of remembering, of thinking, and particularly with the acts of the individual. As in any other science, the aim is first to determine what these activities are, what they do, and then to trace them to their conditions, to understand them in the hght of every fact that can have any bearing upon them. It is easier to show what psychology is and what its aims are by concrete illustration than by abstract statements.

Take memory, for example. Psychology is concerned with knowing all that is possible of how we learn and remember. Every one is familiar with memory in a purely objective way. A lesson is studied and, when occasion arises, much of it can be repeated. How one remembers, troubles the ordinary individual very little. When questioned he knows almost as little of how he remembers as does the questioner. The task of psychology is to discover the laws and conditions of learning and recall in all of their details. It must know what methods lead most certainly and quickly to a first learning, what kind of learning will permit retention for the longest time, and how forgetting takes place. These investigations have been carried out in great detail, as will be seen in a later chapter. While memory itself is regarded as a mental process, the measurements of memory are as objective as are measurements of the strength of materials, although of course the variation is greater from measurement to measurement. The experiments require somewhat complicated special apparatus and a special training in manipulation, and the methods used and the results obtained may be stated in terms that make no mention of mind. Thus, the most satisfactory rate for retention, the best method of distributing the repetitions, the rate of forgetting, are determined by objective tests that hold irrespective of theory. It is also possible to study very many of the conditions of recall by objective methods. One may speak a word and then ask the observer to speak the first word that occurs to him. A study of the connection between these words permits a statement in a perfectly objective way of the laws that hold for recall. These are the facts with which psychology must deal. They may be collected in much the same way for each of the different activities of man.

The Nature of Psychology

Methods of Psychology. — This purely objective and experimental study of mental activities depends upon observation. It may be carried on for man in exactly the same way as for animals, by making experiments from the outside, with no attempt to discover directly what has been going on within the individual. But this is not the only method of psychology. We may also make use of the individual's report on the processes. He can observe from within what accompanies and precedes the activities objectively measured. This, the process of self-observation or introspection, will in many cases supplement the results of direct observation, and the individual who is experimented upon can often supply an explanation when the observer can find none. While the fundamental causes of most mental phenomena are as much hidden from him as from the experimenter, he can add an account of accompanying phenomena that is nearly always suggestive, and may at times furnish a solution for the questions raised by the objective results. The two methods of psychology, then, are observation and introspection. One gives the phenomena as they present themselves to the onlooker, the other as they appear to the individual investigated. At present both methods are used under experimental conditions that make it possible to control the stimuli and to provide means of measuring many reactions that would escape either unaided observation or introspection.

The Definition of Psychology. — While practically all are agreed as to the field which psychology is to study and on most of the results obtained, there is and always has been much controversy over what it is that is studied. Three definitions are current at present which differ in the statement of the object to be studied :

The first asserts that psychology is the science of mind, a direct translation of the original Greek. Two meanings are given to the word 'mind.' One regards it as something substantial, an actual thing or an actual force which produces certain effects or manifests itself in the phenomena we directly experience; the other, of more recent development, asserts that mind is just these manifestations, the sum of mental states without any assumption as to what it is that produces them.

A second definition makes psychology the science of consciousness. Consciousness, like mind in its second definition, is just the series of mental phenomena., the memories, thoughts perceptions, emotions and feelings as they are immediately experienced.

A third definition, most recent of all, defines psychology as the science of behavior. By behavior is meant the activity of the man or animal as it can be observed from the outside, either with or without attempting to determine the mental states by inference from these acts.

The various definitions can be illustrated concretely in the memory process. As theory of mind, psychology regards memory as one of the manifestations of mind and either is concerned with understanding mind through this manifestation or is content to describe remembering as one of the mental capacities. In fact, earlier theories of memory were content to assert that ideas were stored in mind or that they were impressions made upon a waxen plate. In either case, no details could be given as to how they were stored or how they might be reinstated. Mind was both an active agent and a receptacle, the sole means of accounting for mental states. If mind is to be defined as the sum-total of mental states in accord with the more recent suggestions, it is practically synonymous with consciousness, — the first definition merges into the second. As science of consciousness, psychology is concerned with a description of the different memory images, with the determination of the order of their appearance and with all else that is related to their structure and function. It takes into consideration nothing that is not to be discovered by the individual who remembers. It excludes consideration of mind as a storehouse, for that is not open to observation ; and also of mind as a wax plate or other similar entity. All that it can do is to determine the laws of succession of the mental states, and to describe the mental states themselves. As science of behavior, psychology only need investigate the capacity of the individual to remember. The individual is asked to repeat words or syllables a certain number of times under different conditions. After a certain period or certain periods he is tested to see how many he remembers. From these results laws can be formulated for the most effective means of learning.

The second and third of these definitions are alike in that neither implies any theories concerning what cannot be seen, what is not open to observation. Each would content itself with observation, from within or from without, of what actually takes place. As in all sciences, each form of observation may be subjected to experiment, the conditions of learning may be varied at will, the corresponding changes in results noted and formulated in laws. The choice between them must be made in terms of the methods that each emphasizes, and on the basis of the accuracy with which each can be made to cover the facts that are to be included under psychology. In strict definition, all is at once consciousness and behavior for most individuals. Few would deny that all behavior, to be known, must become conscious, either to the actor or observer; and none would deny that consciousness, unless it is to remain forever individual, must express itself in behavior. The choice of the definition 'science of behavior' turns, first, upon the fact that consciousness tends to imply something removed from observation, something mystical, a thing, rather than a series of phenomena; secondly, upon the fact that behavior is the more inclusive term; and finally, upon the doubt expressed by recent writers as to whether consciousness exists, at least exists for them individually. It emphasizes the fact that laws of action must first be discovered, and that theories and theoretical explanations must be derived from the actual results of experiment and observation, rather than be accepted in advance.

Behaviorism. — The most recent development in method and theory has grown naturally from the great progress that has been made in animal psychology. Experiments on animals are of necessity Hmited to an observation of what the animal does under rigidly determined conditions. (Some of the earlier psychologists made inferences from the observed movements as to what mental processes might accompany them, but the results were so unsatisfactory that all assumptions about the consciousness of animals were abandoned.) The success in applying the method of purely objective experimentation to animals emphasized the possibiHty of applying the same method to man. If one could develop the laws of man's action by a study of his responses under different conditions, it would not be necessary to accept the unconfirmed statements of the observer, and would make it possible to check each observation by several individuals or to record them graphically. So far as it can be appHed, the method offers obvious advantages and should be pushed to the fullest extent. Whether this can be the only method in psychology is still a matter of debate. Certain of the questions which interest the psychologist concern mental states, and these have been answered by the older methods. Up to the present time no objective investigations of these problems have been made, and we must either omit them or state the results of the older methods on the older presuppositions. Watson, the extreme behaviorist, relieves himself of the difficulty by omitting all mention of mental states, and by asserting that if they do exist they cannot be made the basis of a science. Many of his more moderate followers are content with emphasizing the desirability of the objective method where available. Consciousness seems to them a fact of immediate experience. If it exists it should be taken into account in a study of behavior, when it contributes relative data. All psychologists, of whatever school, will hail with delight the fullest appHcation of the objective methods; the behaviorists that it may supplant, others that it may supplement, introspection.

The three definitions do not differ essentially as to what the phenomena of consciousness are, nor as to the general laws that express them, but rather in the theoretical explanations which each offers. Thus the exponent of the extreme behaviorist view differs from the extreme subjectivist not in the facts he accepts but in that he does not believe that consciousness exists, or if it exists, that it plays any important part in controlling action. For the subjectivist, on the other hand, consciousness seems the final term by which all else must be explained; behavior is secondary. In the first definition, the use of mind is very obviously the introduction of a theoretical explanation. No one claims that it is ever open to direct observation, however important it may appear to the individuals who beHeve in it. These differences of opinion on theoretical points may very well be neglected in the development of a description of the mental Hfe. After facts have been collected and laws formulated, the fundamental problems may be attacked in the fight of those results. Laws are bound to suggest wider generafizations, and these in turn reveal fundamental causes or conditions.

Psychology Treats Only Certain Phases of Behavior, — Obviously, if we are to define psychology as the science of behavior, we must limit its application, since all of the biological and even the chemical and physical sciences are needed to explain behavior in its completeness. In practice, we Hmit ourselves to the explanation of intelHgent behavior. Roughly, behavior may be regarded as intelHgent when it is modified by the earher experience of the organism. All the acts of certain of the lowest organisms and some of the acts of the highest are to be explained altogether in terms of the physical stimuli and of the constitution of the organism. In consequence, these responses are relatively invariable, — the organism makes the same movements under the same conditions; such responses do not concern psychology. When behavior is modified, not merely by the physical stimuli and chance chemical conditions of the organism, but also by the results of earher behavior, we have the first beginnings of intelHgence, and the organism offers material for- psychology. \Even in the highest organisms, psychology is concerned only with the phases of behavior which cannot be referred directly to chemical and physical changes within and without the organism. It deals in general with the acts of the organism as a whole, rather than of the parts, and it considers the acts of the organism only in so far as they are not explained by physiology and other distinctly biological sciences. In general, again, psychology treats behavior in so far as it is determined by previous acts of the individual, by other more remote influences, while the other sciences treat the same behavior in so far as it is due to the activities of particular organs and to the more mechanical forces.

The Scope oe Psychology

Psychology in its Relation to Other Sciences. — If part of all behavior is to be explained by other sciences, by physiology, by anatomy, and the other biological sciences, the psychologist must take the results of these sciences into consideration. He must know what part of the problem they solve and what they leave over for him to discuss. He must also use many of their results in attaining his own conclusions. Knowledge of the structure and function of the nervous system is particularly important, as in the higher organisms practically all behavior is an expression of nervous action. Capacity for the more complex forms of behavior develops with the nervous system, and defects in the nervous system are closely correlated with deviations from normal behavior. Consciousness, too, is closely related to the nervous system. One can become aware of external objects only as stimuli are carried to the brain by the sensory nerves; memory defects accompany injuries to definite portions of the brain tissue. In fact, we have every reason to believe that all forms of consciousness have definite accompaniments in the nervous system. Viewed from any standpoint, the problems of psychology are closely bound up with the problems of the nervous system. A knowledge of nervous anatomy and physiology is essential to an understanding of either consciousness or behavior. We shall begin our work with a brief survey of the more important facts of neurology. This survey, it may be well to state, is not part of the field of psychology. It is given here only because one cannot presuppose that all readers have a knowledge of the nervous system, and acquaintance with the facts is necessary to an understanding of many definitely psychological problems. A full preparation for commencing the study of psychology makes requisite also the results of physics and chemistry. All of the activities of the organism involve chemical processes, and the stimuli to action are physical. In brief, all of the sciences dealing lo FUNDAMENTALS OF PSYCHOLOGY

with any of the forces that arouse or modify action and with the nature of the organism itself must be of assistance to psychology.

In addition to the sciences to which psychology must look for aid in solving its problems, it also has close relations with many of the social sciences, which either depend upon it or share with it in the solution of their own problems. Sociology in its attempt to understand society must take into consideration the individuals of which it is composed, and welcomes whatever Kght psychology can shed on the subject. In many of its phases sociology is social psychology. Similarly, much of the work in economics depends upon a knowledge of mental laws. The economist, however, has for the most part developed his laws of human nature for himself from a study of practical relationships, rather than from the findings of psychology. The relationship of psychology to philosophy is, for the theoretical problems, closest of all. Psychology was the latest of the sciences to separate from philosophy, and the attitude toward many of the fundamental problems is still profoundly influenced by philosophical considerations. Each of the definitions of psychology discussed has developed in response to philosophical theories. On the other hand, many of the philosophical discussions presuppose a knowledge of psychology. There has always been an interaction between the two disciplines.

Subdivisions of Psychology

The Varieties of Psychology. — The more usual classifications of psychology have been based upon the ways of approaching the subject, upon the methods used in the investigation, or upon the field that is treated. The older psychologies were divided into rational or deductive, and

INTRODUCTION ii

empirical or inductive (on the basis of the fundamental method employed). Recently all psychology has tended to become empirical or inductive, particularly with the increased use of experiment; and the method of deduction has been appHed only to topics that do not lend themselves to experiment or observation. Rational psychology as a separate field has largely disappeared. Even Wolff, who may be said to have introduced and certainly to have made large use of the distinction, was not able to keep the two apart; but was continually turning from one to the other. Two branches have received names from the direction of approach: physiological psychology and psychophysics. The former treats of the mental processes in their relation to the nervous system and its action. It is implied in all forms of psychology at the present time and differs from the others for the most part only in the relative amount of space devoted to the physiological aspects. All psychologists at present presuppose a knowledge of the nervous system and its action, even if they do not discuss it explicitly. Much the same may be said of psychophysics. This lays greatest emphasis upon the part the physical stimuli play in mental processes, and the way in which mental states change with changes in physical stimuli. Both physiological psychology and psychophysics were titles of important works on psychology, the one by Wundt, the other by Fechner. Closely connected with physiological psychology is objective psychology, a name given to several recent books. This not merely places the emphasis upon the nervous system and its activity, but actually leaves consciousness out of consideration altogether. It, like behaviorism, studies behavior from the outside only.

Different Fields of Psychology. — Psychology may be divided with reference to subject matter. Most psychology deals with the adult human individual, but recently manyadditional and special fields have been developed.

Social Psychology. — Society, or man in the mass, may be studied, as well as the individual. A society shows many characteristics different from and in addition to the qualities of the individual. A mob, for example, will do many things that few if any of the individuals who compose the mob would countenance in calm moments. These and other phases of group psychology have been studied, and a series of important laws developed. Race psychology deals with the broader mental differences between races and is a natural extension of social psychology but has been less fully developed.

Genetic Psychology. — A second group of divisions of psychology, genetic psychology, treats the less developed types, either with the object of throwing Hght upon more complex human behavior or for their own sake. The most fully developed of these is animal psychology. The question as to whether or not animals are intelHgent and how their intelligence compares with man's has always interested students, but until within the last two decades most of the conclusions were based upon anecdotes or, at most, upon the chance observations of travellers and naturahsts. These were obviously not trustworthy. More recently, experiments upon animals have been carried on by both biologists and psychologists, with very important results. The behavior of typical animals from the protozoa to the apes has been studied exhaustively. Much light has been thrown upon their own activities, and many points in human psychology have also been illuminated by these results. The development of the individual has also been investigated. Child study has offered a number of conclusions that make easier an understanding of the compHcated activities of man. The earKest years and the period of adolescence have received most attention.

Abnormal Psychology. — -Still another important series of problems has arisen in connection with different forms of mental deterioration, the psychology of the abnormal, or pathological psychology. The relation of these studies to normal psychology has been twofold. They have greatly aided in an understanding of the normal individual. One is very much more certain that a voluntary act depends upon certain stimuli or sensations when it can be shown that the absence of that stimulus causes a defect in the movement. Disturbances of the self have given a more profound knowledge of what the self is or is not than centuries of speculation and introspection. Slighter defects of sensation, color bhndness and partial deafness, not to mention the impairment of memory and related processes, have all given valuable aid in the unravelling of psychological problems, or have substantiated results obtained in other ways. On the other hand, psychological methods and psychological results have been adapted to the study of the abnormal and defective minds with much theoretical and practical benefit. Certain standardized tests have come into use which make it possible to determine within fairly close Hmits the degree of intelligence of the individual. These have proved of value in the schools in selecting the children who are unable to profit from the usual training, and make it possible to give them special instruction. It has been shown by an examination of criminals and paupers that, in a large number of cases, a mental defect is responsible for their failure to fit into society; and the necessity for special care that shall provide the ounce of prevention has been emphasized. Many of the methods used to-day for the diagnosis of insanity have also been developed in psychological laboratories, and much of the treatment has been an outgrowth of psychological principles, an application of psychological methods.

Our Problem. — In this work we shall restrict ourselves to a study of the normal adult human individual. Reference will be made to the other branches of psychology only in so far as their results aid us in understanding this central problem; they render valuable aid at practically every point. We shall use the results of all methods, but shall enter as little as possible into the controversies as to whether any one method is theoretically justifiable. We shall assume that there is a body of fact that is independent of the theoretical discussions. Thus, in connection with the difference of opinion as to whether observation or introspection is the method in psychology, we shall remain neutral, and make use of the contributions of each method. After all, the controversy concerns us only in its effect upon the form of expression that may be used to state the results rather than in the validity of the results themselves. Most of these results may be expressed equally well in terms of one theory or the other, and where they cannot we shall use the terminology best suited to the particular statements in hand. The facts are important and will persist, while the theories that interpret them are in constant flux. We shall be concerned primarily with facts, and the theories will be considered only where they serve to make clear the facts.

Angell: Chapters in Modern Psychology.

Watson: Psychology from the Standpoint of a Behaviorist, Ch. I.

Bertrand Russell: The Analysis of Mind.

Warren: Human Psychology, Ch. I.

Woodworth: Psychology, Ch. I.

Chapter II The Nervous System

Broadly speaking, the physical basis of mind is to be found in the nervous system. In a very general sense, the nervous system is the organ of mind. When, however, we approach it from the physical side, it is also the organ which makes possible the activities of the body, which permits external stimuli to act upon the muscles, and coordinates the different movements so that they may bring about harmonious and unified action. An understanding of the action and even of the structure of the nervous system is very much easier if we keep the emphasis upon the relation of the nervous system to bodily movement — treat it first for itself — ■ than if we think of it in its relation to consciousness. The problem of the relation of body and mind may be taken up when we know more of body. The nervous system in vertebrates is made up of the brain and spinal cord with the sensory and motor nerves that extend from these central organs to the sense organs and muscles. The brain fills the upper part of the skull, while the spinal cord is found in the spinal column. The details of the structures can be understood more readily if we consider them later in connection with their development in the race and in the individual.