SCIENTIFIC PROCEDURE.
The Detailed Subject Matter of Scientific Psychology.— As a science psychology puts before herself the task of unraveling the complex factors involved in the development of human behav- ior from infancy to old age, and of finding the laws for the regu- lation of behavior. At first sight it may seem that this program leaves out many of the factors with which psychology ought to be concerned. Historically considered, this is true, but when e are confronted both with the practical and scientific needs of lift* we are ready to admit that, after all, what we seek to have PROBLEMS AND SCOPE OF PSYCHOLOGY 9 psychology busy herself with is just this matter of environmental adjustment; what man can do apart from his training; what he can be trained to do, and what the best methods for training are; and finally, how, when the varied systems of instincts and habits have sufficiently developed, we can arrange the conditions for calling out appropriate action upon demand. To solve such problems we must: necessarily study the simple and complex things which call out action in man; how early in life he can react to the various simple and complex sense stimuli; at what age he usually puts on the various instincts, and what the situations are which call them out. Just what is the pattern of his instinc- tive acts — that is, does the human being, apart from training, do any complex acts instinctively as do the lower animals? If so, what is man 's full equipment of instincts? When does emotional activity manifest itself? and what are the situations which call it out? and what special acts can be observed in emotional behav- ior? How soon can we observe the beginnings of habit in infants? What special methods can we develop for rapidly and securely implanting and retaining the body and speech habits which society demands? Do we find special and individual equipments in infants, and do these develop, and, later, form the basis for their entering one kind of vocation or another, or developing into one or another type of personality? Are there such factors as habit and instinct conflicts, distortion of habits and emotions? How do they manifest themselves? and is it possible to develop methods for shaping the environment of the individual so that such conflicts will not arise? What in general are the factors which affect the functioning of habits once they are acquired?
Stimulus and Response. — This general description of the subject matter of psychology helps us very little as regards the analysis of particular problems in conduct and behavior. In order to plan an experimental attack upon any problem in psychology we must first reduce it to its simplest terms. If we look over the list of problems in human behavior given in the preceding paragraph, and at our practical examples, we shall see that there are common factors running through all forms of human acts. In each adjustment there is always both a 10 PSYCHOLOGY 10 PSYCHOLOGY response or act and a stimulus or situation which call out that response. Without going too far beyond olir facts, it seems pos- sible to say that the stimulus is always provided by the environ- ment, external to the body, or by the movements of man's own muscles and the secretions of his glands; finally, that the responses always follow relatively immediately upon the presentation or incidence of the stimulus. These are really assumptions, but they seem to be basal ones for psychology. Before we finally accept or reject them we shall have to examine into both the nature of the stimulus or situation, and of the response. If we provisionally accept them we may say that the goal of psycho- logical study is the ascertaining of such data and laws that, given the stimulus, psychology can predict what the response will be; or, on the other hand, given the response, it can specify the nature of the effective stimulus.
Use of the Term Stimulus. — We use the term stimulus in psychology as it is used in physiology. Only in psychology we have to extend somewhat the usage of the term. In the psycho- logical laboratory, when we are dealing with relatively simple factors, such as the effect of ether waves of different lengths, the effect of sound waves, etc., and are attempting to isolate their effects upon the adjustments of men, we speak of stimuli. On the other hand, when the factors leading to reactions are more complex, as, for example, in the social world, we speak of situa- tions. A situation is, of course, upon final analysis, resolvable into a complex group of stimuli. As examples of stimuli we may name such things as raj's of light of different wave lengths; sound waves differing in amplitude, length, phase, and combination; gaseous particles given off in such small diameters that they affect the membrane of the nose; solutions which contain par- ticles of matter of such size that the taste buds are thrown into action; solid objects which affect the skin and mucous mem- brane; radiant stimuli which call out temperature response; noxious stimuli, such as cutting, pricking, and those injuring tissue generally. Finally, movements of the muscles and activity in the prlands themselves serve as stimuli by acting upon the afferent nerve endings in the moving muscles.
PROBLEMS AND SCOPE OF PSYCHOLOGY 11 It must be emphasized here that only under the rarest experi- mental conditions can we stimulate the organism with a single stimulus. Life presents stimuli in confusing combinations. As you write you are stimulated by a complex system — perspiration pours from your brow, the pen has a tendency to slip from your grasp; the words you write are f ocussed upon your retinae; the chair offers stimulation, and finally the noises from the street constantly impinge upon your ear-drum. But far more impor- tant, delicate instruments would show that, though you are not speaking aloud, your vocal mechanisms — tongue, throat and laryngeal muscles — are in constant motion, moving in habitual trains; these laryngeal and throat movements serve largely as the stimuli for releasing the writing movements of the hands. The fact that you are here in the lecture room, facing your instructor and surrounded by your classmates, is another very important element. The world of stimulation is thus1 seen to be exceedingly complex. It is convenient to speak of a total mass of stimulating factors, which lead man to react as a whole, as a situation. Situ- ations can be of the simplest kind or of the greatest complexity. It should be noted here, finally, that there are many forms of physical energy which do not directly affect our sense organs. As examples we may cite the facts that ether waves longer than or shorter than 397/x,/*, do not lead to visual reactions, and at many of the wave motions in the air are of such length or amplitude that they do not produce auditory stimulation. The inability of the human organism to respond to many possible forms of stimulation will be discussed later.
The General Nature of Response. — In a similar way we employ in psychology the physiological term "response," but again we must slightly extend its use. The movements which result from a tap on the patellar tendon, or from stroking the soles of the feet are ' ' simple ' ' responses which are studied both in physi- ology and in medicine. In psychology our study, too, is: some- times concerned with simple responses of these types1, but more often with several complex responses taking place simultaneously. In the latter case we sometimes use the popular term "act" or adjustment, meaning by that that the whole group of responses 12 PSYCHOLOGY is integrated in such a way (instinct or habjt) that the individual does something which we have a name for, that is, ' ' takes food, ' ' ' ' builds a house, " " swims, " " writes a letter, " " talks. ' ' 2 Psy- chology is not concerned with the goodness1 or badness of acts, or with their successfulness, as judged by occupational or moral standards. Because a man fails by his separate acts to get his food, to build his house, to work out his mathematical problem, or to live in harmony with his wife, is no reason for rejecting him as a psychological subject. We study him for his reaction possi- bilities and without prejudice; the discovery of the fact that he will make only abortive attempts to meet and control certain aspects of his environment is an important part of our task; just as important as being able to state that he can make certain other types of adjustment. "Successful" adjustments, "good" acts, "bad" acts, are terms really which society uses. Every social age sets up certain standards of action, but these standards change from cultural epoch to cultural epoch. Hence they are not psychological standards. Eeaction possibilities, however, on the average probably remain about the same from eon to eon. It lies well within the bounds of probability that if we were able to obtain a new-born baby belonging to the dynasty of the Pharaohs, and were to bring him up along with other lads in Boston, he would develop into the same kind of college youth that we find among the other Harvard students. His chances for success in life would probably not be at all different from those of his classmates. The results obtained from the scientific analysis of reaction in the human being should fit any cultural age. It is part of the function of the psychologist to tell whether a given individual has the reaction possibilities within him to meet the standards of that cultural age, and the most rapid way of bring- nm to act in accordance with them. The fact that social •But it should be well understood that whatever the man does under illation is a response or adjustment-blushing, increased heart-beat Aspiration, etc., are definite part adjustments. We have ie of these earned act,. In this volume the tern, adjustment, Me, and reaction are used almost interchangeably.
PROBLEMS AND SCOPE OF PSYCHOLOGY 13 values (group mores} change puts ever new burdens upon the psychologist, because every change in the mores means a differ- ent situation, to which man has to respond by a differ- ent combination of acts, and any new set of acts must be incor- porated into and integrated with the rest of the action systems of the individual. The problems put up to psychology are those of deciding whether the individual can meet the new standards, and for determining and developing methods of instructing him. Motor and Glandular Indicators of Response, — What is it that the psychologist can observe? Behavior, of course. But behavior on analysis is the separate systems of reactions that the individual makes to his environment. When we come to study the mechanics of such adjustments we find that they depend upon the integra- tion of reflexes connecting the receptors with the muscles and glands. It should be emphasized here that objective psychology does not analyze such integrations to the bitter end except where the problem demands it. Concrete, whole activities are as impor- tant to the behaviorist as to other psychologists (see page 40).
The unicellular organisms have no separate muscular or nervous systems. Yet a part of their one cell must be specialized in a motor as well as in a sensory way, since these organisms do move in response to stimuli — to light, gravity, heat, cold, elec- tricity, etc. As one passes higher in the animal scale one finds that special sense-organ tissues (receptors) develop, and along with them both motor or effective organs, and neurones connect- ing receptors and effectors. Action in such cases becomes sharper, more localized, more immediate, and at the same time more sustained. Furthermore, as we pass still further up the scale, glands begin to develop. Glands, like muscles, are responsive organs, and special glandular action takes place whenever motor action takes place. The activity of the glands in turn reacts upon the muscular system and affects its functioning (p. 218). Furthermore, there are two kinds of muscles, striped and unstriped. The striped muscles move the arms, legs, trunk, tongue and larynx. The unstriped muscles control largely the blood-vessels, intestines, the organs of elimination and sex. Usually when we speak of response we mean that the organism 14 PSYCHOLOGY 14 PSYCHOLOGY goes forward to right or left, or retracts asta whole, that it eats, drinks, fights, builds houses, or engages in trade. But these patent and easily observable changes do not exhaust the term response, as we pointed out on page 12. We should mean by response the total striped and unstriped muscular and glandular changes which follow upon a given stimulus. Our problem of the moment determines which movement shall be studied in rela- tive isolation; in man, though, interest has been largely centered in the integration of separate responses; in getting him to form some habit — that is, to do something with arms or legs1 or vocal cords. It is important to get at the outset a comprehensive notion of response. A man or animal may stand stock still under stimu- lation, but we should not say that there was no response. Close observation shows that there are changes in the tension of the muscles, in respiration, in circulation, and in secretion.
The General Classification of Responses. — The various pos- sibilities of reaction are thus seen to be vast; so vast, indeed, that it would seem at first sight as though.any classification would be impossible. We can at least find a convenient grouping which will serve both for discussion and for setting experimental prob- lems. Most reactions may be looked upon as falling into one of four main classes: 1. Explicit habit' responses: as examples we cite unlocking a door, tennis playing, violin playing, building houses, talking easily to people, staying on good terms with the members of your own and the opposite sex.
2. Implicit habit responses: "thinking," ly which we mean subvocal talking, general body language habits, bodily sets or attitudes which are not easily observable without instrumentation or experimental aid; the system of conditioned reflexes in the various glands and unstriped muscular mechanisms— for example, conditioned salivary reflexes.
3. Explicit hereditary responses: including man's observable instinctive and emotional reactions as seen, for example, in grasp- ing, sneezing, blinking and dodging, and in fear, rage, love.
4. Implicit hereditary responses: this includes, of course, the whole system of endocrine or ductless gland secretions (p. 181), . PROBLEMS AND SCOPE OF PSYCHOLOGY 15 changes in circulation, etc., so largely studied by physiology. Here again instrumentation or experimental aid is necessary before observation can be made.
These various types of response will be studied in detail in later chapters. The classification as a whole should be clear, with the possible exception of 2 (implicit habit responses). This group is so important and so generally neglected in discussion that we shall single it out here for brief mention in advance of the chapter in which it is entered into with some care.
What Man is Doing When Not Overtly Acting. — With a highly specialized organism like man, even careful observation often fails to show any overt response. A man may sit motion- less at his desk with pen in hand and paper before him. In popular parlance we may say he is idle or "thinking," but our assumption is that his muscles are really as active and possibly more active than if he were playing tennis. But what muscles? Those muscles which have been trained to act when he is in such a situation, his laryngeal, tongue, and speech muscles generally.3 Those muscles are as active and are carrying out as orderly a system of movements as if he were executing a sonata on the piano; they are doing it well or ill, depending upon the training 'he has had along the particular lines which engage him. While we cannot at present watch the play of this implicit stream of words, there is no reason for hypothecating a mystery about it. Coiild we bring "thinking" out for observation as readily as we can tennis playing or rowing, the need of "explaining" it would disappear. We shall see later that efforts have been made to bring such responses under experimental control. But entirely apart from our present unreadiness to make observation on implicit habits, we find a certain, way of arriving indirectly at the same end: implicit language habits, by methods which wer shall study, come to issue finally in overt action. By watching the easily observable explicit habits and instincts of an individual keenly enough, and for a sufficient stretch of time, and under varying enough conditions, we can obtain the necessary data for most psychological requirements.
3 Indeed, the whole glandular and muscular systems are contributory.
16 PSYCHOLOGY Scientific Methods Contrasted with Practical Procedure. — Having now examined at some length into the general nature of both stimulus and response, we should be prepared to under- stand the object 'of a psychological experiment and to contrast the scientific procedure with the common-sense or practical pro- cedure which We discussed at the beginning of the chapter. We shall take up almost at random some definite illustrative psy- chological problems, and the methods of solving them. Our first problem is to find out what the reactions of a six-months-old infant are to living, furry animals. We first arrange the situa- tion (complex group of stimuli, p. 10). The infant is held by its mother in a well-lighted room. We observe first that the infant is smiling, and comfortably disposed. Then, one after another, we present a white rat, a dog, a cat, a white rabbit, beetles, and a snake. We next record accurately and separately the reactions to these objects. The infant, which has only learned to reach out for objects a short time before, slowly puts out first one hand and then the other. The smile leaves his face, but no crying or withdrawing of the hands or external secretions fol- lows. These are only the more easily observed responses. Other changes take place undoubtedly, in the internal glands, circula- tion, respiration, etc. It depends upon our immediate problem as to where the emphasis in observation shall fall in our record of reaction changes. In this ease our problem was to determine whether there were any overt instinctive tendencies on the baby 's part to react against or withdraw the hands or whole body from live animals. Our problem might very well have led us into observing the changes in the eyes, respiration, blood-pressure, salivation, or in the endocrine glands, or in several of these at once. Again, it should be noted that our problem is not so simple %s it seems at first sight. Suppose we had found that the baby did withdraw from the objects, began to cry, void urine, or attempt to hide behind the mother's clothing — could we have concluded that there was an instinctive reaction against live furry animals? Not without delving into the laby's past. If we had had the child under constant observation, and found no record of previous acquaintanceship with live animals, our PROBLEMS AND SCOPE OF PSYCHOLOGY 17 answer would be that the observable responses were probably instinctive. But if, on the other hand, we found that the child had been Severely bitten by a cat only two days before our test, our conclusions would have to wait upon more extended observa- tion. Nor can we, from the behavior of this one child, draw any conclusions as to what other children of the same age will do, or what this child might do at a slightly different age or when tested under different conditions. Before generalizations can be made many children should be brought under systematic observation.
As another example of a somewhat more restricted type, let us take the case of a man whose every-day behavior has led us to suspect the normality of his responses to monochromatic (col- ored) light. Common-sense has nothing to say; it can give no adequate report on him. His mistakes may be due to one or many things. We take him into the laboratory where monochromatic light is under control, and we put him in situations where he has to react to the lights in pairs, and where each one of the lights can be widely varied in energy. In the course of the investiga- tion we find that when there is a certain energy relation obtaining between the red and the green light he can no longer react to them differentially (that is to say, they do not offer different stimulat- ing values). We note further that we can find a white light of a certain intensity to which he reacts as he does to either of the monochromatic lights. But at no energy relation between any other two colors can we break down his differential responses. We conclude after this careful study that the man is red-green blind, that is, that he reacts to red and green as he does to certain intensities of white light.4 Let us take another example, and this time from the field of vocational psychology. Suppose that the telephone directory of a large city is getting entirely too bulky and complex for men to handle easily. What is the best method for obviating this? The telephone people and the psy- 4 If we find by repeated tests that the anomaly is more than temporary, we are right in advising this man that he will be handicapped if he enters certain occupations, e.g., locomotive and marine engineering, geology, adver- tising, etc. In otheif words, the results of psychological experimentation are as immediately practicable as are results in any other scientific field.
18 PSYCHOLOGY chologists work together. The psychologist m#y suggest printing in smaller type and four columns to the page instead of three. These and many other possible suggestions may lead to a solu- tion of the problem. But the matter has to be put to severe trial both at the hands of individuals trained to look up names in a directory and individuals having no more training than has the general public. Systematic trial and error is the procedure here, with statistical treatment of the results. In the end it is found that a four-column page with a certain amount of spacing between the lines of print makes the directory not only 20 per cent, less bulky, but also one in which the subscribers can find names 10 per cent, more rapidly (Baird).
THE DIVISIONS OF PSYCHOLOGY AND THE RELATIONS OF PSYCHOL- OGY TO THE OTHER SCIENCES.
The Various Fields of Psychology. — It is just as difficult to draw a hard-and-fast line between the different branches of psychology as between the different branches of biology and of physics. Practical and theoretical interests determine where a man will throw the emphasis of his observation. All scientific psychology is experimental, or is at least carried out under such conditions that rigid and controlled observation is possible. All psychology is * ' genetic ' ' in the sense that we have to go back to the child and contrast it with animals in order to determine what native systems of integrations belong peculiarly to man. For purposes of specialization we speak of human psychology as being made up of individual, vocational, child, folk, educational, legal, pathological and social psychology. We may speak of any of these special branches as being "applied." For our purposes we need not enter into a separate characterization of these special branches. The remaining chapters in this book attempt to deal generally with the simpler results, problems, and methods in common use in psychology. We shall not emphasize, except here and there, the particular branch to which such material belongs.
Relation of Psychology to Physics. — Both physiology and psychology are dependent (as is every other science at bottom) upon physics for the control of apparatus and of stimulus. It is essential for a research student in psychology now to know the PROBLEMS AND SCOPE OF PSYCHOLOGY 19 general facts about wave motion; as, for example, heat, sound and light. It is important to know how to install and use simple electrical instruments, galvanometers, thermal couples, and photometers.