PAUL B.HOEBEK MEDICAL BOOKS OLIV€R F. CDflDSCDPRTH FUND BEHAVIOR An Introduction to Comparative Psychology BY JOHN B. WATSON Professor of Psychology in The Johns Hopkins University NEW YOEK HENRY HOLT AND COMPANY Copyright, 1914, BY HENRY HOLT AND COMPANY To my Friends and Teachers JAMES R. ANGELL and HENRY H. DONALDSON this Book is Gratefully Dedicated.
in 2010 with funding from Open Knowledge Commons and Harvard Medical School PREFACE This volume on behavior is an elaboration of the eight lectures given at Columbia University during the winter of 1913. It has been written with the hope that it may be found serviceable in classroom work in psychol- ogy and biology. Needless technicalities and detailed references have been omitted. For this reason the general reader may find something of interest in its pages. The book must not be looked upon as a reference book or treatise. The treatment of the research material has not been exhaustive. For the most part no attempt has been made to give investigators detailed credit for their work. I have not, however, been able to carry out consistently the plan of omitting references. In most sciences which have existed for any length of time a general body of data be- comes common property, and it is unnecessary to mention the original discoverers of the universally accepted facts. Some parts of the study of behavior are so involved in con- troversy that no results can be said as yet to be universally accepted by specialists in the subject. In dealing with these facts, especially in the chapters on the sense organs, it has been necessary to enter with some detail into the discussion of the investigations and theories of individual writers. It is hoped that the volume will contribute some- thing towards the introduction of more careful methods in the study of behavior, and serve to mark off the study from the other sciences.
An endeavor has been made to adapt the book to the needs of various classes of readers. Where only a short time can be devoted to a classroom course in behavior, I suggest that chapters I, II, III, V, VII, and IX be omitted.
In the preparation of the manuscript my heaviest obliga- tion is to Dr. K. S. Lashley, Bruce Fellow in Biology, the Johns Hopkins University. He has given unsparingly of vi PREFACE his time in helping in the actual preparation of the chap- ters on the origin of instincts and the fixation of arcs in habits. Dr. H. M. Johnson has assisted me greatly by fur- nishing the drawing and description of the Helmholtz method of tandem-driven forks.
I owe a heavy debt of gratitude to my colleagues Profes- sors Arthur 0. Lovejoy and Knight Dunlap for kindly criti- cisms and helpful suggestions during the preparation both of the Columbia lectures and of the manuscript of the book. My long and intimate association with Eobert M. Yerkes and with Harvey Carr has been of great benefit to me. I owe them much more than can be gathered from a mere reading of the following pages.
Finally I wish to express my indebtedness to my secre- tary, Miss Clarice Shoemaker, who has been untiring in her work upon the manuscript.
The Johns Hopkins University, CONTENTS CHAPTER I PAGE Psychology and Behavior 1 Unsatisfactory nature of present psychological premises. — The nature of the behaviorist's program. — The image as an implicit form of behavior. — Affection as a form of in- stinctive behavior. — Summary.
CHAPTER II Some Problems Enumerated 29 No lack of unity in behavior problems. — Field versus laboratory studies. — Grouping of problems. I. Sense organ processes. — Introduction. — 1. Vision. — Necessity for con- sidering anatomical structure. — Reflex responses to light. — General division of problems in vision. — (a) White light vision. — (6) Response to monochromatic light. — 2. Audi- tion.— Grouping of problems. — (1) Response to pendular vibrations. — (a) Range of sensitivity. — (6) Localization — (c) Response to clangs. — (2) Response to a-periodic vibra- tions.— (a) Stimulus threshold. — (&) Difference threshold. — (3) Response to ordinary sounds in the environment. — (a) Instinctive repertoire of sounds. — (&) Modification of vocal sounds through social influences. — (c) Influence of such sounds upon mates. — 3. Olfaction and gustation. — Lack of definite knowledge about smell functions. — Prob- lems in olfaction. — Function of olfaction in habit forma- tion.— Problems in gustation. — 4. Cutaneous, proprio- and entero-ceptive systems. — Difficulties in the way of making satisfactory tests. — Proprio-ceptive - system. — Cutaneous system as a distance receptor. II. Instinctive functions. — Introduction. — Some types of instinctive response. — The animal's instinctive mode of attack on problems. — Instinct and habit. III. Learning. — ^Introduction, — Grouping of problems. — (1) Perseverance method. — (2) Efficiency of training methods. — (3) Complex forms of learning. IV. Correlations. — Introduction. — Lack of behavior data handicaps the neurologist. — General aim of behavior. — Summary.
vii viii CONTENTS CHAPTER III p^GE Apparatus and Methods...56 Introduction. — I. Stimulus to general activity: stimuli to locomotion. — (a) General stimuli positively responded to. — ( 1) ) General stimuli negatively responded to. II. Methods of studying the receptors of animals: forcing the formation of sensory habits. — Control box. — Pawlow's method. — Methods dependent upon instinctive response. — Control and auxiliary methods. — Criticisms of the methods for determining the sensitivity of receptors. III. Appa-. ratus for obtaining specific stimuli: apparatus for obtain- ing monochromatic light. — Use of apparatus. — The selenium cell. — Device for securing a purified spectrum. — Apparatus for testing response to white light, form, and size. — Ap- paratus for producing auditory stimulation: apparatus for obtaining constant air supply. — The Helmholtz system of tandem-driven forks, — Animal control box for work on audition. — Yerkes' apparatus for testing hearing in frogs. — Apparatus for obtaining olfactory and cutaneous stimuli. — Yoakum's temperature apparatus. IV. Methods of studying motor habits: introduction. — The problem box method. — Description of boxes. — Description of maze experiment. — Apparatus for the study of the delayed reaction.
CHAPTEE TV CHAPTEE TV Observational and Experimental Studies upon Instinct 106 Use of term. — Broader definition of term reflex de- manded.— Content of term reflex as used in behavior. — General types of instinct. — Methods of studying instinct. — Various results obtained by the method of field observa- tion.— Instinctive activity of birds: the noddy tern. — Instinctive activity of reptiles. — Instinctive activity of fish. — Special forms of instinctive activity in fish. — Results of the experimental study of instincts. I. The initial performance of some instinctive acts. II. Serial un- folding of instinctive acts of young captive animals: (a) Guinea pig; (&) Rat; (c) Monkey; (d) Sooty tern. III. Quantitative study of improvement of instinctive function. IV. Modification of instinct through social influences. _ V. Hereditary character of certain instinctive acts and traits. VI. Waning of instinct: loss through disuse, etc.
CHAPTER Y Concerning the Origin of Instincts...148 Introduction. — Early differentiation of parts. I. Hered- ity: the concept of unit characters. — Unit characters. — CONTENTS ix PAGE Mendel's experiments. II. Origin of diversities in organ- isms.— Introduction. — Darwin's conception of variations. — Continuous variation due to direct action of the environ- ment upon the developing organism. — The non-inheritance of continuous variation. — Discrete variations or mutations. — Frequency of mutations. — Cause of mutations. — The Dar- vi^inian conception of selection. — Changes in the concept of natural selection. — Effect of natural selection upon muta- tions.— ^Ability to form habits enables the animal to supple- ment a faulty inheritance. — Some special forms of adap- . tations. (a) Protective resemblance. (&) Warning colo- ration, (c) Sexual dimorphism. III. Inheritance of ac- quired characters. — Lamarck's laws. — Recent experiments upon the inheritance of acquired characters. — The experi- ments of Kammerer. — Some evidence negative in character. — The direct adaptation theory. — Summary.
CHAPTER VI The Experimental Study of Habit Formation. 184 I. Content of term habit. — Restatement. II. Types of habit. — Motor habits; mammals. — Motor habits; birds. — Motor habits; fish. — Motor habits; reptiles. — Habits of manipu- lation; mammals. — Habits of manipulation; birds. — Sen- sory habits. III. Curves of learning; motor habits. — Curves of learning; sensory habits. — Motor habits in human beings. — Comparative learning ability of different animals. IV. The rise of habits when incentives are controlled. — Habits formed without the use of punishment. — With punishment as the sole incentive. — With punishment for wrong response and food for right response. V. Analysis of reflexes in- volved in habit. — Normal and operative methods of elimi- nating sensory impulses. — Some results of experimental analysis of motor habits in mammals. — ^Analysis of motor habits in birds. — ^Analysis of sensory habits in mammals. — Analysis of the delayed reaction in mammals. — Summary. VI. Efficiency of training methods: motor habits. — Sensory habits. — The delayed reaction. VII. Other conditions which affect learning. — ( 1 ) Age. — ( 2 ) Sex. — ( 3 ) Certain bodily conditions. — (4) Learning in animals with less than nor- mal brain weights. — Motor habits in animals with parts of nervous system removed. VIII. Effect of previous habits upon the formation of new habits: motor habits.
IX. Retention. — Mammals. — Birds. — Amphibia and rep- tiles.
CHAPTER YII Fixation of Arcs in Habit 251 Introduction. — Historical outline. — ^Misconceptions and illogical presuppositions. — Enumeration of some of the X CONTENTS PAGE problems. — Factors involved in fixation. — ^Application of the principle of frequency in motor habits. — Justification for the use of the principle. — ^Application of the principle of recency in motor habits. — Sensory habits. — Substitution. — Repetition of movement in absence of original stimulus. — Conclusions.
CHAPTER VIII The Abridgment of the Learning Process.. 277 Introduction. — Lloyd Morgan's clasisification of imitation, — Localizing and enhancing the stimulus. — Putting the ani- mal through the act. — Presentation of experimental results: Introduction. A. Primates. B. Cats. C. Dogs. D. Rac- coons. E, Rodents. F. Birds. — Summary.
CHAPTER IX The Limits of Training in Animals...297 Introduction. — Some gifted animals. — (1) Clever Hans. — (2) The horses of Elberfeld. — Claparede's examination; results of the first set of observations. — Later tests by Claparede. — Tests on morning of the 26th of March. — Afternoon of March 26th. — March 28th, morning and after- noon.— Tables of results. — (3) Peter. — (4) Don. — (5) Jasper. — Summary.
CHAPTER X Man and Beast 317 Introduction. — ^Man and animal. — The lack of language habits differentiates brute from man. — Instinctive basis of language. — The nature of language habits. — Early predomi- nance of language habits. — Forms of language habits. — Futility of the search for reasoning, imagery, and the like in animals. — Division of labor between human and animal behaviorists.
CHAPTER XI Vision 335 Introduction. — I. Limits of spectral sensitivity and rela- tive stimulating eff"ect of different regions of the spectrum. ■ — Mammals. — Birds with day vision. — Birds with twi- light vision. — Hess' absorption theory. — In fish. — In rep- CONTENTS xi PAGE tiles and amphibia. II. Darkness-adaptation; white light. — Introduction. — Darkness-adaptation in birds with day- light vision. — In birds with twilight vision. — In fish. — In reptiles and in amphibia. III. Darkness-adaptation: monochromatic light. — In birds. — In reptiles and in am- phibia. IV. Sensitivity to wave-length. — In mammals. — In birds. — Denibnstration of the Purkinje effect. — Results from a physiological method of testing for color sensitivity. —Mimicry or adaptation to background no test of color sensitivity. — In reptiles and in amphibia. — Delicacy of the problem in color sensitivity. V. Response to white light. — Mammals. — Birds. — Fish. — Amphibia and reptiles. 'VI. Response to form and size. — In mammals. — In birds. — In reptiles and in amphibia.
CHAPTER XII Auditory and Eelated Functions...370 Introduction. — Some structural differences in the audi- tory organs. — Auditory responses in mammals. — (a) The dog: Kalischer's experiments. — Rothman's experiments. — Further experiments by Kalischer. — Johnson's experiments. — Experiments made by the Pawlow method. — Experiments of Syzmanski on localization. — (6) The cat: response of cats to tones, noises, and to articulate sounds. — (c) Rac- coons: reactions of raccoons to tones and articulate sounds. — Tests upon mice and rats. — Incidental tests upon other mammals: (a) Monkeys. (6) Horses, (c) Bats. — Audi- tory response in birds. — In pigeons and parrots. — Audi- tory response in amphibia. — Frogs. — Auditory response in fishes. — Some investigators who report lack of auditory sensitivity in fishes.^Investigators reporting sensitivity to auditory stimuli. — Intensity of sound stimuli in water. — Summary. — The lateral line organs.
CHAPTER XIII Smell, Taste, and the " Common Chemical Sense " 399 I. Smell. — Olfactory reactions in mammals. — Romanes' test of the hunting dog. — Difficulties in the way of explain- ing the hunting behavior of dogs. — Experiments on the olfactory sensitivity of birds. — The sense of smell in fishes. — Experiments by Parker and Sheldon. II. Taste. — ^Loca- tion of gustatory organs. — Herrick's experiments upon the functional significance of the taste buds. — Parker's experi- ments upon the gustatory responses of fishes. III. The " common chemical sense." — Introduction. — Sheldon's ex- periments upon the smooth dogfish. — The " common chemi- cal sense " in amphibia. — Summary.
xii CONTENTS CHAPTER XIV PAGE Cutaneous, Organic, and Kinesthetic Senses. 421 I. Cutaneous. — Cutaneous sensitivity in mammals. — Halm's experiments upon the bat. — The " sense of support " in mammals. — Yoakum's experiments upon the temperature sense in mammals. — Contact sensitivity in fish. — Contact and temperature sensitivity in amphibia, II. The organic system. III. The kinsesthetic system.
Index 433 BEHAVIOR An Introduction to Comparative Psychology BEHAVIOR CHAPTER I PSYCHOLOGY AND BEHAVIOR ^ Unsatisfactory nature of present psychological premises. — The na- ture of the behaviorist's program. — Ihe image as a form of implicit behavior. — Affection as a form of instinctive behavior. — Summary.
Unsatisfactory nature of present psychological prem- ises.— Psychology as the behaviorist views it is a purely objective experimental branch of natural science. Its theo- retical goal is the prediction and control of behavior. In- trospection forms no essential part of its methods, nor is the scientific value of its data dependent upon the readiness with which they lend themselves to interpretation in terms of consciousness. The behaviorist attempts to get a unitary scheme of animal response. He recognizes no dividing line between man and brute. The behavior of man, with all of its refinement and complexity, forms only a part of his total field of investigation.
It has been maintained by its followers generally that psychology is a study of the science of the phenomena of consciousness. It has taken as its problem, on the one hand, the analysis of complex mental states (or processes) into simple elementary constituents, and on the other the construction of complex states when the elementary con- stituents are given. The world of physical objects (stimuli, including here anything which may excite activity in a receptor), which forms the total phenomenon of the natural scientist, is looked upon merely as means to an end. The ^ A few new terms have been used in this discussion of behavior — such as heJiaviorist, hehavioristic, heJiaiHorism. While it is admitted that these words sound somewhat barbaric on a first hearing, they at least have the merit of being expressive and natural. _ Indulgence is also asked for the use of " perseverance method " in place of " trial and error " method in the description of the experiments on learning.
2 PSYCHOLOGY AND BEHAVIOR end is the production of mental states that may be '' in- spected " or " observed." The psychological object of observation in the case of an emotion, e.g., is the mental state itself. The problem in emotion is the determination of the number and kind of elementary constituents present, their loci, intensity, order of appearance, etc. It is agreed that introspection is the method par excellence by means of which mental states may be manipulated for purposes of psychology. On this assumption, behavior data (including under this term everything which goes under the name of comparative psychology) have no value per se. They possess significance only in so far as they may throw light upon conscious states.^ Such data must have at least an analogical or indirect reference to belong to the realm of psychology.
Indeed, one finds at times psychologists who are skeptical of even this analogical reference. Such skepticism is often shown by the question which is put to the student of behavior, ** what is the bearing of animal work upon human psychology? " With psychology based upon its present premises such a question is necessarily embarrassing for the reason that no answer is open to the man who uses animals for subjects. The behaviorist has found it convenient in the past to cultivate a repressed attitude when talking of his work before orthodox psychologists. He is interested in this work and believes firmly in its intrinsic value, albeit he is unable to trace its bearing upon psychological theory. Such a confession it is hoped will clear the atmosphere to such an extent that the behaviorist will no longer have to work under false pretenses. We in turn must frankly admit that the facts which we have been able to glean from extended work upon the senses of animals by behavior methods have contributed only in a fragmentary way to the general theory of human sense organ processes: and that they have not even suggested new ways of making experimental attacks upon the problems of human psychology. The enormous number of experiments ^ I.e., either directly upon the conscious state of the observer or indirectly upon the conscious state of the experimenter.
PSYCHOLOGICAL PREMISES 3 which we have carried out upon learning has likewise contributed little to human psychology. It seems reason- ably clear that some kind of compromise must be effected; either psychology must change its viewpoint so as to take in facts of behavior, whether or not they have bearing upon the problems of " consciousness; " or else behavior must stand alone as a wholly separate and independent science. Should human psychologists fail to look with favor upon our overtures and refuse to modify their position, the be- haviorists will be driven to use human beings as subjects and to employ methods of investigation which are exactly comparable to those now employed in the animal work. Any other hypothesis than that which admits the independ- ent value of the behavior material will inevitably force us to the absurd position of attempting to construct the conscious content of the animal whose behavior we have been studying. On this theory, after having determined our animal's ability to learn, the simplicity or complexity of its methods of learning, the effect of past habit upon pres- ent response, the range of stimuli to which it ordinarily re- sponds, the widened range to which it can respond under experimental conditions, — in more general terms, its various problems and its various ways of solving them, — we should still feel that the task is unfinished and that the results are worthless, until we can interpret them by analogy in the light of consciousness. Although we have solved our problem we feel uneasy and unrestful because of our definition of psychology: we feel forced to say something about the possible mental processes of our ani- mal. We say that, having no eyes, its stream of conscious- ness cannot contain brightness and color sensations as we know them, — ^having no taste buds this stream cannot contain sensations of sweet, sour, salt, and bitter. But on the other hand, since it does respond to thermal, tactual, and organic stimuli, its conscious content must be made up largely of these sensations; and we usually add, to protect ourselves against the reproach of being anthropo- morphic, "If it has any consciousness." Surely this doctrine which calls for an analogical interpretation of all 4 PSYCHOLOGY AND BEHAVIOR behavior data must be shown to be false: the position that the value of an observation upon behavior is determined by its fruitfulness in yielding results which are interpret- able only under the concept of consciousness.
This emphasis upon analogy in psychology has led the behaviorist somewhat afield. Not being willing to throw off the yoke of consciousness he feels impelled to make a place in the scheme of behavior where the rise of conscious- ness can be determined. This point has been a shifting one. A few years ago certain animals were supposed to possess '' associative memory," while certain others were supposed to lack it. One meets this search for the origin of con- sciousness under a good many disguises. Some of our texts state that consciousness arises at the moment when reflex and instinctive activities fail properly to conserve the organism. A perfectly adjusted organism would be lack- ing in consciousness. On the other hand, whenever we find the presence of diffuse activity which results in habit formation, we are justified in assuming consciousness. Such arguments have weight with the neophyte, but as time goes on and the horizon of animal work broadens, he becomes less and less convinced of their weight. Many of us are still viewing behavior problems with something like this in mind, as is evidenced by the fact that more than one student of behavior has attempted to frame criteria of the psychic — to devise a set of objective, structural, and functional criteria which, when applied to the particular instance, will enable him to decide whether such and such responses are positively conscious, merely indicative of consciousness, or whether they are purely ' ' physiological. ' ' Such problems as these can no longer satisfy behavior men. It would be better to give up the province altogether and admit frankly that the study of the behavior of animals has no justification, than to admit that the search is of such a " will o' the wisp " character. One can assume either the presence or the absence of consciousness any- where in the phylogenetic scale without affecting the problems of behavior by one jot or one tittle; and without influencing in any w^ay the mode of experimental attack PSYCHOLOGICAL PREMISES 5 upon them. On the other hand, one cannot for a moment assume that the Paramecium responds to light; that the rat learns a problem more quickly by working at the task five times a day than once a day, or that the human child exhibits plateaux in his learning curves. These are ques- tions which vitally concern behavior and which must be decided by direct observation under experimental condi- tions.
This attempt to reason by analogy from human conscious processes to the conscious processes in animals, and vice versa, to make consciousness, as the human being knows it, the center of reference of all behavior, forces us into a posi- tion similar to that which existed in biology in Darwin's time. The whole Darwinian movement was judged by the bearing it had upon the origin and development of the human race. Expeditions were undertaken to collect material which would establish the position that the rise of the human race was a perfectly natural phenomenon and not an act of special creation. Variations were care- fully noted and along with them the evidence that they might be heaped up along lines which would be of service to the animal; for in this and the other Darwinian mechan- isms were to be found factors sufficiently complex to account for the origin and race differentiation of man. The wealth of material collected at this time was considered valuable largely in so far as it tended to develop the concept of evolution in man. It is strange that this situation should have remained the dominant one in biology for so many years. The moment zoology undertook the experi- mental study of evolution and descent, the situation im- mediately changed. Man ceased to be the center of reference. It is doubtful if any experimental biologist today, unless actually engaged in the problem of heredity in man, tries to interpret his findings in terms of human evolution, or ever refers to it in his thinking. He gathers his data from the study of many species of plants and animals and tries to work out the laws of inheritance in the particular type upon which he is conducting experi- ments. Naturally he follows the progress of the work upon