Psychology, General and Applied
Chapter 5: Scope and Methods of Causal Psychology
Hugo Münsterberg
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The Subdivisions of Psychology.—Wherever mental life exists, it must be possible to take the objective point of view toward it and to consider it as a content of an individual consciousness. As such, it is material for the description and explanation. Hence the realm of causal psychology is as wide as that of mental life. Where the furthest boundary of this realm lies may seem debatable. There is only one test for the existence of consciousness, namely, our subjective, practical acknowledgment. If someone acknowledges the reality of inner attitudes in the spider, but not in the jellyfish, we have no objective method to prove that the mental life begins at another stage. Not a few feel inclined to extend the realm even further down and to acknowledge mental life in the reactions of certain plants when they turn toward the light or respond to contact. Very little depends upon such shifting of the lower limit; we certainly all agree that from the insects upward to the leaders of mankind we have a world of mental life in which many different degrees of mental development and mental complexity can be found. A real comparison with the lower forms of mental life does not lie in our compass. We shall emphasize the biological aspect and the continuity of the development, but the interest in man's mind is our predominant issue.
If we are to draw one decisive frontier line between two large groups in human psychology, it ought to be between the mental life of the individuals and that of the social
( 44) groups. Of course, there is no mental process in the social group which is not contained in individual minds. The inspirations and impulses and ideas of a nation are, as material for causal psychology, only contents of consciousness in millions of individual persons. And yet the psychologist has good reasons to acknowledge the significant difference. The circle of those who are mentally combined in society may be large or small, may be a state or merely a family : in any case the combination of such individual cerebral systems is far more than a mere summation of the single members. New forms of psychophysical life and new results arise from the mutual influence. Here really a new kind of psychological experiences is found and new groups of psychological interests are touched.
We shall accordingly divide the causal psychology into individual and social psychology. At one point the two fields overlap. The large group of interesting facts which refer to the individual differences of men may just as well be treated in the one as in the other department. If we study individual psychology, we are led from the simple states to those most complex formations which constitute the personal individuality. The end point of individual psychology is therefore the observation of the individuals in their differences. But this is exactly the starting point for the social psychologist. Society might exist through the combination of individuals who are all alike. But the society which experience really shows us receives its manifoldness and its complexity above all from the great variety of persons who enter into it. Society is a combination of unlike individuals, and to consider the individual as a member of society means first of all to characterize him in his difference from the other members. For this reason we shall often point to personal differences in the discussion of individual psychology, but the real study of personal variations will be the introductory chapter of our social psychology. The same double function is
( 45) characteristic of child psychology and abnormal psychology. We shall refer to the mental facts of childhood and of disease in discussing the mind of the individual, but we shall consider them chiefly when we deal with the human differences in social psychology.
All the other usual groupings of psychological facts refer to other aspects. The discrimination, for instance, of educational psychology, legal psychology, medical psychology, industrial psychology, refers to the standpoint of the practical psychologist, which will interest us in the last part of the book. On the other hand, if we speak of experimental psychology, physiological psychology, comparative psychology and so on, we do not characterize different groups of material, but different methods by which this material is to be mastered.
To be sure the term physiological psychology can mean not only psychology as studied by physiological methods, but also psychology as an account of mental states in their relation to physiological brain processes. To us this is not a special part of causal psychology, inasmuch as we have convinced ourselves I hat we cannot have psychological explanation at all, if we do not consider every psychical process as part of the psychocerebral correlation. We may have to deal with individual or with social psychology, with animal or with human psychology, with child psychology or with abnormal psychology : in every case we deal with physiological psychology, even if we often abstract from the physiological aspect.
A more dangerous characterization of psychology is proposed by the too frequently used term functional psychology. The word is so easily misleading, because it has at least two entirely different meanings. The difference becomes clear through the contrast to structural psychology. The structure of the mind and the functions of the mind are related to each other as the anatomy of a bodily organ is related to its physiology. The one has a static, the other a dynamic, character. Structural psychology describes that which can be found in consciousness at a given instant, and functional psychology shows how
( 46) successive mental states are parts of a process which leads to certain ends. The one takes a cross-section of the stream, and the other follows the stream itself.
If we interpret the meaning of structural and functional psychology in this way, it is clear that, they belong intimately together. The functional aspect is then not in the least contradictory to the structural. They supplement each other, and while we discuss the function, we never forgot, that it is described in constant reference to the structure. Both are essential parts of causal psychology. But the term functional is just as often used with an entirely different meaning. The function is then no longer a series of describable objective states analogous to the function of a bodily organ. But it is the mental act itself in its purposiveness, as it is experienced in the attitude of the self. Functional psychology is then entirely removed from the world of describable objects and understood as an account of those functions in the personality which point beyond themselves and are felt as deeds of the subject. In short, it is the psychology which we call purposive. If the word functional is used in this sense, it does indeed stand in contrast to structural psychology and the latter term is then usually expanded so far that it covers the whole ground of causal psychology, including the structural account of mental functions.
In order to evade the difficulties of this double meaning, we shall avoid this too popular phrase altogether. It has greatly hindered the mutual understanding in modern psychology. This, however, in no way means that we shall neglect either of the two different accounts of functional psychology. As far as it is the same as our purposive psychology we shall present its claims in full detail, as soon as we have ended the discussion of causal psychology. On the other hand as far as it means the dynamic aspect in the midst of causal psychology, we shall certainly do the fullest justice to it as it is only the natural consequence of the theory of psychophysical parallelism which we have accepted. If the mental states are understood as accompaniments of brain processes, they are completely linked with the bodily life of the organism and through it with the whole psychophysical development. This whole psychocerebral process will appear to us as the central part of that complex biological func-
( 47) -tion by which the individual adjusts himself usefully to his surroundings. The psychophysical process thus enters into the system of organic reactions, which can never be understood if they are not related to their useful effects. Hence we are everywhere obliged to emphasize the functional aspect in the midst of causal psychology, and any effort to confine the work to a mere structural account would leave out the most important and the most interesting feature.
Selfobservation.—If we were to divide the whole realm of causal psychology from the point of view of the various methods, the fundamental division ought to lie between the psychology based on selfobservation and the psychology based on the observation of others. The division line must not be misunderstood. The material which the psychologist secures by the method of selfobservation is certainly not confined to that which he finds in his own personal consciousness. All the mental experiences which fellow-workers observe in themselves and report to him count for him just as much as if he had observed them in his own mind. As soon as we are in the midst of psychological work, we cannot go back to philosophical doubts concerning the reality of the fellow's mind; we take it for granted that he can observe his content of consciousness as well as we observe our own. If somebody else describes to me his afterimages or his headache, I accept it as material gained by the introspective method just as if I myself observed the colors or the ache. The essential point is not whether I or someone else experiences it, but whether the observer and the observed are the same person, or not. If the child simply cries and laughs, he experiences I he feelings, but I observe them.; the case is therefore not one of selfobservation. And if the melancholic patient shows to me that he is brooding on sad ideas, again I am I lie observer and he is the observed. If we call the psychological observation which is not introspective an indirect observation, every study of the mental life of animals or of
( 48) infants or of seriously diseased persona will be mostly indirect. Moreover we may carry on indirect observations on any one of our neighbors who on another occasion may furnish us with direct observational results. The one easily shades off into the other. The child may describe his inner experiences, and we gain through this introspective accounts; and yet we may at the same time observe the child's behavior and draw indirect conclusions as to his inner states, which may be very different from his own reports.
Selfobservation or introspection is certainly the fundamental method. Yet we cannot deny that it is surrounded with serious difficulties. They can be found in various directions. The method of introspection has often been denounced because it is an activity which goes on in the same mind in which the processes occur which are to be observed. As all activities in our mind influence one another, it is to be feared that this effort to observe the inner changes often destroys its object. There is an element of truth in this. If a poem has filled our mind with a subtle, delicate feeling tone, and suddenly our scientific effort of selfobservation breaks in so as to fixate those shades of feeling, the chances are great that the whole affection may evaporate, because it was disturbed by the entirely different mental setting.
If we are depressed or angry or enthusiastic for men or events, we are hardly able to turn our introspective attention on these inner excitements, and if we force our will to introspecting, the enthusiasm or the anger will be inhibited. But we can well combine the will to observe with the undisturbed experience of a perceptive impression or of a memory image or of imaginative experiences or even of a thought. Moreover the emotional and volitional excitement which does not allow a neutral spectator on the fence of our consciousness may be brought back by a later act of memory, and we may observe and analyze by intro
( 49) -spection today the emotional excitement of yesterday. A hove all the ability to live through a mental experience in its original freshness and yet to take inner snapshots of it may be strongly developed by training. Anyone interested in psychological analysis can acquire a certain skill in combining the attitude of observing with the practical life attitudes, just as we can learn to perform two different movements with the two hands without mutual interference.
Even if our selfobservation is careful and backed by knowledge of the bodily processes, it is evident that it must be confined to those chance experiences which the stream of life bears to our shore. Every individual experience is narrowly limited, and if we observe only what the accidents of the day bring into our sphere, our material will be scanty and insufficient for a systematic study of mental possibilities. Many selfobservers may bring together the outcome of their introspection; yet the results must be haphazard as long as they are confined to that which presents itself to them by chance. Worst of all, these results must be extremely vague and rough. Really careful and subtle discrimination is hardly possible, and the comparison of the effects of different conditions cannot be expected, if the conditions themselves are not under control. Unaided selfobservation, therefore, appeared a satisfactory method in the history of human thought, only as long as psychology was essentially a speculation about the human soul. The vague general impressions which the thinker received from the working of his will or emotion or memory were sufficient as starting points for the soul philosophy which did not have to be a science of experience.
But since the psychologist has turned into the new path, and like the naturalist aims toward the goal of scientific description and explanation, the merely occasional glances at his own mental life can no longer satisfy the student of the mind. He must on the one side supplement the self-
( 50) observation by the observation of others whose mental experiences are different from his own, and on the other side he must bring selfobservation itself under carefully controlled conditions and make it independent of the haphazard events of the day. But however desirable such expansion of method is, and however necessary for every serious study, it certainly cannot mean a disregard of the introspective method. Those observations of others always need interpretation in the light of selfobservation, and all those exact and subtle means for the analysis of our own mental life remain, after all, only refinements of selfobservation. Even the work of the psychological laboratory, in which the experiment controls the mental experience, is in no way opposed to selfobservation: on the contrary, it is only a better and more systematic selfobservation, adjusted to the higher scientific demands.
Indirect-Observation.—We may turn first to the efforts to extend the observation beyond our own mental life. Introspection is direct observation. Therefore we must now ask : how does the psychologist supplement it by indirect observation? We presuppose at first that this indirect study proceeds under the natural conditions of life without artificial interference. The characteristic feature then is that the observer and the observed are no longer the same person. It is clear that no one will turn to the stranger whom he must observe from without in order to find that which he can find in himself. Yet we saw from the start that the effort to observe, especially subtle or strong emotions, may interfere with the mental states themselves. Hence we naturally turn to the watching of fellowmen if we want to trace the undisturbed development, and particularly the expression, of feelings and emotions, impulses and volitions.
But the chief value lies in the study of those cases in which the mental life is different from our own. The study of the mental abnormities, for instance, may be treated not
( 51) as a department with special objects, but as a scientific method needed to discover the subtler interplay of the normal mental functions. The diseased mind is composed of the same elements as the normal mind: only their proportion is changed. There is too much or too little of one or another mental feature. To observe the distorted mind therefore helps us in the understanding of the normal harmony and proportion, as a caricature may help us to recognize the proper interrelations between the features of the face. The study of the abnormal is in this case not controlled by the interest in the traits of the disturbed mind, but in their value for the analysis of the normal mind. In the same way child psychology may serve as a method. We compare the consciousness of the adult with the simpler and simpler forms in the mind of children; we may trace the ideas of space and time and number, or the ideas of one's own personality or the ideas of fellow-beings and similar highly complex structures in our mind down to the elementary forms in youth, in childhood and in infancy, and understand their composition through the comparison. The study of different species or of different races, of different ages or of different pathological variations is indirect in so far as the observer is not the observed, but it brings at least the organism into the field of direct observation. We can go still a step further and gather mental material from individuals who do not come into contact with us at all.
We have this in the case of statistical results, which, especially in the form of the so-called moral statistics referring to occupations and vocations, crimes and suicides, marriages and divorces, education and religion, and many other results of psychical motives in the national body, are important for the study of social psychology. Another line of study is opened if we turn to the archives of history. The records of the past, with their accounts of unusual minds, heroes or artists, martyrs or criminals,
( 52) all speak of mental structures and mental functions which are sufficiently different from the routine mind to attract the interest of the psychologist.
This again must be supplemented by the study of the objective products of minds: it may be the work of individuals, such as an artistic or scholarly or religious or political creation; it may be the achievement of the masses, such as languages or laws or customs or policies or religions. They all reflect light on the mental mechanism which brought them into existence. We can study the differences of minds in studying the differences between the works of architecture which old India or Egypt or Assyria or Greece or Rome have left to posterity ; and the changes of the historic languages can be understood as the products of simple psychophysiological processes, which repeat themselves in millions of individuals. We might even take a last step and acknowledge that the poet also furnishes us with material which allows observation of. mental processes. The persons of his epic and dramatic works are not real, and he himself is not a causal psychologist, as he creates minds, but does not describe and explain them. But if we usually call a great poet like Shakespeare a great psychologist, we mean that his imagination has created individuals whose mental acts are so lifelike and internally true that the psychologist can substitute them in his studies for real personalities.
Experimental Psychology.—Thus direct and indirect observation combined can bring an abundance of material from the marketplaces of life to the workroom of the psychologist; and yet of this indirect study it may be said, as we had to say about the direct introspection, that true thoroughness and exactitude cannot be reached as long as everything is left to the chance offerings of nature. The chemist and the physicist do not leave it to the current of natural events to bring up the phenomena which deserve scientific interest. They build their laboratories and
( 53) produce there artificially conditions under which the observations can be repeated in ever-new forms and under complete control of the factors which enter into the event. The experiment of the naturalist is indeed nothing but the observation of the physical or chemical processes under conditions which are artificially introduced for the purposes of the observation. The psychologist too can hope for a perfection of direct and indirect observation only if he introduces experimental methods. In the persistent effort to make use of the experiment for the study of causal psychology lies the most characteristic feature of the psychology of the last decades.
This was the decidedly new turn on account of which modern psychology is not seldom called the new psychology, in striking contrast to the preceding two thousand years of psychological interest. In the past the study of the mind, in spite of its essentially philosophical character, did not lack elements of empirical observation, but the observations were confined to mental life under natural conditions. With the middle of the nineteenth century the observation under artificial conditions begins. The psychologists themselves were not the leaders in the new method. The physiologists who studied the functions of the eye and ear and of the muscles were led to experiments which threw light on mental facts and gave the strongest impulse toward an independent interest in mental experiments. Suggestions came also from other neighboring sciences. Physicists examined experimentally the relations between the strength of the physical impressions and the inner sensations. Even the astronomers found reasons to experiment with regard to mental functions, as it was observed that the correct observation of the stars depended upon mental conditions, which varied among different observers. It became necessary to measure the rapidity with which the individual mind reacted on the astronomical stimulus, and that led to general experiments
( 54) on the quickness of mental processes. Not a few psychological experiments were carried on in this way before the psychologists began to establish special laboratories for their own purposes. The first institute, which was to be the mother institute of most psychological laboratories the world over, was founded in Leipzig In 1879. It was devoted exclusively to selfobservation under artificial conditions, and it naturally began with such simple experiments as those which had been carried on in the neighboring fields before. The development was an unusually quick one; the movement spread to all countries, Germany and the United States leading in this now interest. America has at present more than half a hundred psychological laboratories.
The internal development, however, was still more rapid. In its early days it seemed a matter of course that only elementary processes would be accessible to experimental methods. The borderland regions between mind and body, the sensations and perceptions, space and time problems, the simplest association and reaction questions were the natural field, while the higher mental activities seemed beyond reach. But, as soon as the psychologists had their own keys, many new doors could be opened. The experimental method was soon successfully brought to the study of memory and of attention, later of feelings and emotions, of thoughts and esthetic states and volitions. Certainly the experiment under laboratory conditions is as yet not equally developed in all regions of mental life, and is so far better adjusted to the problems of perception and memory than to those of emotion and will. Yet it can be said that there is no group of mental processes which has not been made accessible to the experimental method.
But the triumph of the laboratory is not confined to the rich development of methods for exact selfobservation. Its aid is no less significant in the regions of indirect observation. The old animal psychology consisted of anec-
( 55) -dotes of dogs and horses, hunting stories and onesided interest in the mental life of ants and bees; the experiment transformed it into an exact science which traces every mental function through the whole kingdom of animals. Child psychology was not in the same degree dependent upon experimental methods, as the opportunities for steady observation under natural conditions were more favorable, and much excellent detail had been observed by parents and teachers before the experiment aided the study. Moreover it is evident that the hygienic interests of the child set rather narrow limits to persistent experimentation. Yet here too the experiment has been applied with full success from the reactions of the infant in its first minutes of life to the complex mental processes of the adolescent. In the same way the laboratory method has shed new light on the disturbances of the diseased mind, and still more on those abnormities which lie in the borderland between health and illness. Moreover in the sphere of mental abnormity the experiment has taken still another form. The aim is not only to carry on experimental studies with the abnormal mind, for instance, research on the abnormal memory or intelligence or feeling, but to produce by experiment abnormal mental states in otherwise normal men. The typical case is that of hypnotism. The hypnotic experiment is certainly an effective means for the discovery of many psychological facts which cannot be studied under normal conditions.
The whole science of psychical life is thus revolutionized by the methods of experiment, and throughout has been victorious in this sign. But its strength ought not to be misinterpreted. We have emphasized before that the experiment does not stand in contrast to selfobservation and is by no means superseding it, but only aiding it. We have to add now that it is no less misleading, if it is brought into contrast with the qualitative analysis of mental states and is glorified as a scheme to perform a quantitative measurement of the conscious experience. On
( 56) the surface it looks indeed as if the laboratory work were measuring mental states as such. If we look deeper, we recognize that this is an illusion. All which we measure are physical quantities, and all the figures which enter into our laboratory report refer ultimately to physical conditions of mental experience. The mental experience itself remains only a qualitative manifoldness. The mental states are alike, or are different, but one never contains a number of others. A physical ten-candlepower light contains ten times the light of out candle, but the psychical light impression of the strong light, does not contain so and so many time the light impressions of the weaker. The strong and the faint impression are different, but we cannot find the one in the other. All physical measurements are based on the counting of units. The ten-foot distance contains ten times one foot. But in the world of impressions or other mental states neither the contents themselves nor their differences from one another can be put together and summed up.
If we call two mental states equal, the term must not be used in the mathematical sense. It means only that we do not discriminate qualitative differences. If we were to apply arithmetic to the mental relations themselves, we should be entirely misled. If we start with a red sensation and go through all shades of red orange to orange and so on by smallest steps to yellow and green and blue and violet and purple, we can count the number of just noticeable differences, and this number would be much larger for the distances from red to purple throughout the rainbow colors than from red to green; and yet psychologically red and purple are very similar, and show a very small difference, while red and green are very different. The knowledge of ten pages of text is not ten times the knowledge of one page; the memory image of two men is not twice the memory image of one man; we cannot have the same anger or the same volition three times. We have no right to believe that exact psychology has made the mental life itself measurable. The exactitude refers to the discrimination of qualitative differences on the mental side and careful measurement of the causes and effects on the physical side. This is not a weakness of present day psychology which the future may overcome, but it is one of the deepest characteristics of the psychical material itself.
( 57)
Only one further methodological aspect must be mentioned. All the methods of direct and indirect observation under natural and under experimental conditions referred to the mental states and their relation to preceding or following physical events. We have not yet spoken about the ways by which the correlation between the mental event and the accompanying parallel brain process is determined. Such methods can hardly be called psychological, however important the results of such work may be for the theoretical explanation of the psychologist. In the foreground here are the methods of anatomy, of physiology and of pathology. The anatomist traces the connections between particular brain parts and the sense organs or the muscles, and in this way can throw light on the psychophysical functions of those nervous centers. The contribution of the anatomist becomes especially important through comparative anatomy. If certain mental abilities are characteristic of some animals, while they are rudimentary in others, the anatomist can find out whether a particular region of the central nervous system is highly developed in the one and undeveloped in the other group.
But the more direct aid to this side problem comes from the physiologist, who studies directly how far the artificial stimulation of a certain brain region produces in the animal an expression of mental activity and how far the artificial destruction of the same central region results in an interference with that particular form of mental behavior. And finally the pathologist gathers the material which the dissection of the diseased brain after the death of the patient exhibits. If certain mental functions had become defective during lifetime and the autopsy now shows a degeneration of special brain tracts, the pathologist links the mental and the physical disturbances. In the middle of the last century the discovery of characteristic lesions of the brain in cases of speech defects gave to
(
58) psychology an impulse in this direction which led to a long series of
most important researches. These pathological observations, on the other hand,
were constantly supplemented by the physiological experiments and aided by the
rapid progress of comparative anatomy. In this way the theory of psychocerebral
parallelism found its fullest development in the same few decades in which
experimental psychology was unfolding. The results of both are combined in the
system of modern causal psychology.
