Psychology and Industrial Efficiency

XI

While the psychologists have to perform the actual labor, the representatives of practical life are much better able to indicate the points at which the psychological levers ought to be applied. In the past year I have sought contact with several hundred large concerns in America which belong to many different industrial realms. My time did not allow me personal observation in so many cases, but everywhere I begged for information from the leading men. I asked in individual letters for the particular psychological qualities which from the standpoint of the management seemed essential for the various kinds of labor in their establishments. I always inquired to what extent consideration was given to such psychological points of view at the appointment of applicants, and asked for material concerning the question how far individuals who proved to be unfit for one kind of labor showed fitness at other kinds of work. The replies which I received from all sides varied from a few meaningless lines to long documents, which in some cases were composed of detailed reports from all the department chiefs of a particular concern. The common fundamental turn was decidedly a feeling of strong interest in the formulation of the question, which was practically new to all of them. Whether the answer came from paper mills or machine shops, from meat-packing houses or from breweries, from electrical or chemical mills, from railroad or mining companies, from department stores or from publishing houses, everywhere it was acknowledged that they had given hardly any conscious attention to the real psychological dispositions of their employees. They had of course noticed whether their men were industrious or lazy, honest or dishonest, skillful or clumsy, peaceful or quarrelsome people, but I had emphasized from the start in all my letters that such points of view were not before my mind. The mental qualities for which I asked were the psychological functions of attention, memory, ideas, imagination, feeling, volition, suggestibility, ability to learn, ability to discriminate, judgment, space-sense, time-sense, and so on. It would lead too far here to discuss why these two groups of characteristics indeed belong to two different aspects of mental life, and why only the latter is strictly psychological. The way in which the management is accustomed to look on their men is the practical way of ordinary life, in which we try to understand our neighbor by entering into the meaning of his mental functions and by seeking to grasp what his aim is. But such an interpretation of the other man's mind is not a psychological analysis. It gives us the purposes of his inner life, but does not show us its structure and its component parts. We can abstract from interpreting and appreciating in order to describe the elements of the mind which in themselves have no meaning and no value, but which are the only important factors, if we are to determine psychologically what we may expect from the individual.

While the replies to my letters showed that hardly any attention had so far been given to such problems of objective psychology in the industrial concerns, it became evident that the managers felt distinctly that here a problem was touched which must be of highest importance for economic success. From many different sides willingness was shown to study the problem of employment under the psychological aspect. As my material came mostly from very large establishments in which labor of very many different kinds is carried on side by side, of course I frequently received the assurance that whenever an industrious energetic man is unsuccessful in one kind of work, a trial is made with him in another department, and that by such shifting the right place can often be found for him. Young people, to whom, in spite of long trial and the best will, it seems impossible to supply certain automatic machines, become excellent workers at much more difficult labor in the same establishment. Women who are apparently careless and inattentive when they have to distribute their attention over a number of operations do high-class work when they are engaged in a single activity; and in other cases the opposite is reported.

I may mention a few concrete chance illustrations. In a pencil factory the women in one department have to grasp with one movement a dozen pencils, no more and no less. Some learn this at once without effort, and they earn high wages; others never can learn it in spite of repeated trials. If those who fail in this department are transferred, for instance, to the department where the gold-leaf is most carefully to be applied to the pencils before stamping, very often they show great fitness in spite of the extreme exactitude needed for this work. To show how often activities which appear extremely similar may demand different individuals, if the work is based on different psychical functions, I may refer to a report from one of the largest establishments in the country. In the accounting department a large number of girls are occupied with looking over hundreds of thousands of slips from which the weekly pay-list is compiled. Each slip contains six figures and small groups of twenty slips have to be looked through to see whether those six figures on each correspond. With moistened forefinger they turn up the slips one by one in much the same manner that a bank clerk counts money. A good sorter will turn up the slips so rapidly that a bystander is unable to read a single figure, and yet she will not overlook an error in thousands of slips. After the slips are sorted, the operation of obtaining the totals on each order number is performed with the aid of an adding machine. The machine operator rolls up the slips of the pile with the thumb of her left hand and transfers the amount to the proper keys of the machine. It has been found that the most rapid and accurate girls at sorting are not seldom useless on the machines. They press the wrong, keys and make errors in copying the total from the machine indicators to the file-card. On the other hand, some of the best machine operators are very slow and inaccurate at the sorting table. Girls have been found very poor at the work at which they were first set, and very successful and efficient as soon as they had been transferred from the one to the other.

Examples of this kind might be heaped up without end. But while the very large establishments demonstrate by such reports only that they can find somewhere a fit place for every able workingman if they take enough trouble to seek for it, after all the essential element of the reports remains, that successful achievement depends upon personal mental traits which cannot be acquired by mere good will and training. In view of this fact it is much more important that by far the majority of establishments have not such a great manifoldness of activities under one roof. The workingman who is a failure in the work which he undertook would usually have no opportunity to show his strong sides in the same factory, or at least to be protected against the consequences of his weak points. If his achievement is deficient in quality or quantity, he generally loses his place and makes a new trial in another factory under the same accidental conditions, without any deeper insight into his particular psychical traits and their relation to special industrial activities. But even in the large concerns, in which many kinds of labor are needed side by side, it is not the rule but a rare exception when the individual is systematically shifted to the psychologically correct place. A whole combination of conditions is necessary for that. If his mental unfitness makes him unsuccessful in one place, the position for which he is fit must happen to be vacant. Moreover, he himself must like that other kind of work, and above all the foreman must recognize his particular fitness. In a few model factories in which the apprentice system is developed in the spirit of advanced sociological ideas, for instance, in the Lynn factory of the General Electric Company, such systematic efforts are being carried on and show fair results. But the regulation plan seems to be a haphazard lack of plan, and even the best endeavors probably fall short of what may be attained by the introduction of scientific psychological methods. So far in most factories the laborer who is not doing well simply loses his position, and by such an unfortunate experience he is not mentally enriched but impoverished, as he has lost much of his self-confidence and of his joy in labor.

If this limitless waste of human material, this pitiable crushing of joy in the day's work, and this crippling of the economic output is at last to be reduced, indeed nothing is more needed than a careful scrutiny of the various psychophysical functions involved in the work. A mere classification of the industrial occupations according to the classes of manufactured objects would be of no value for this need, as often a small industrial concern may embrace occupations which, are based on many different psychophysical functions. A harvester consists of two hundred and fifty different parts, and almost every one of these parts demands a long series of manufacturing, processes. Thousands of different kinds of labor are thus combined in one factory and each process demands for the best work particular psychophysical traits, even though many of them can be carried out by quite unskilled laborers. In a large manufacturing establishment the manager assured me only recently that more than half a million different acts have to be performed in order to complete the goods of that factory. On the other hand, it evidently is proper to form larger groups in which processes are brought together which are similar with reference to the mental activity needed, while they may be dissimilar from the standpoint of industrial technique.

This analysis of the special processes can be furthered best by the coöperation of the experienced men of industry. Many of the replies which I received contained quite elaborated contributions to such a study of various industrial processes from a psychological point of view. They sometimes covered the ground from the simplest activity to the subtlest and most difficult economic tasks, and this, not only with reference to the functions of the laborer, but also even with reference to the function of the industrial manager. The outsider can see these psychological requirements of the particular occupation only in crude outlines. The subtler nuances of differences between tasks can be gained only by an intimate knowledge of the industry. Again I may give an illustration. In the case of a well-known typesetting machine, thousand of which are in daily use, I had the impression that the rapidity of the performance was dependent upon the quickness of the finger reaction. The managers, on the other hand, have found that the most essential condition for speed in the whole work is the ability to retain a large number of words in memory before they are set. The man who presses the keys rather slowly advances more rapidly than another who moves his fingers quickly, but must make many pauses in order to find his place in the manuscript and to provide himself with new words.

The factors which are to be brought into correlation are, accordingly, first, the actual experiences of the managers, secondly, the observations of skilled psychologists in the industrial concerns, thirdly, psychological and experimental investigations with successful and unsuccessful laborers, and, fourthly, experimental studies of the normal variability. If such a programme is to be realized in detail, it will be necessary to discriminate carefully, between those mental traits of the personality which must be accredited to a lasting inherited disposition and such as have been developed under the influences of the surroundings, by education and training, by bad or good stimuli from the community. While those acquired traits may have become relatively lasting dispositions, their transformation is, after all, possible, and the limits in which changes may be expected will have to be found out by exact studies. Individual psychological rhythm, attention and emotion, memory and will energy, disposition to fatigue and to restoration, imagination, suggestibility and initiative, and many other features will have to be examined in their relation to the special economic aims.

Too much emphasis cannot be laid on another function as well, the experimental testing of which has only recently been started. I refer to the difference in the individual ability of men to profit from training. If we test an individual at a certain point in his life with regard to a variable ability, our result must be dependent upon three factors, the original disposition for the performance, the original disposition for the advance by training, and the training itself actually passed through up to that moment. A small amount of antecedent training for the particular task together with a high ability to profit from repetition may be a better reason for the appointment of a man than a long training with small ability to profit from schooling, in spite of the fact that his actual achievement at this time may be in the first case smaller than in the second. He will do less at first, but he promises to outrank the other man after a period of further training. Special experiments must be carried on and have been actually started to determine this plasticity of the psychophysical apparatus as an independent inborn trait of the individual.[16]

This invasion of psychology into the field of economic activities is still so little advanced that the thought of a real distribution of the wage-earners among the various commercial and industrial positions on the basis of psychological tests would lead far beyond the present possibilities. Moreover, many factors would interfere with its being carried out consistently, even if a much higher stage of experimental research were reached. The thousands of social and local reasons which influence the choice of a vocation to-day would to a certain degree remain in force also in a period of better psychological analysis. Moreover, the personal inclinations and interests naturally would and ought to remain the mainspring of economic action. This inclination, which gives so much of the joy in labor, is by no means necessarily coincident with those psychophysical dispositions which insure the most successful work. Political economists have found this out repeatedly from their statistical inquiries. Very careful studies of the textile industry in Germany carried out in recent years[17] yielded the result that the intelligent, highly trained textile laborer often dislikes his work the more, the more he shows ability for it, this ability being measured by the wages the individuals earn at piecework. The wage and the emotional attitude were not seldom inversely related. Those who were able to produce by far more than others and accordingly earned the most were sometimes the very ones who hated the work, while the less skillful workers earned less but enjoyed the work more. The consulting economic psychologist will, therefore at first reasonably confine himself to warning the misfits at an early time. Even within these limits his service can be useful to both parties, the employers and the employees. He will only slowly reach the stage at which this negative warning may be supplemented by positive suggestions, as to the commercial industrial activities for which the psychophysical dispositions promise particular success.

A real assumption of responsibility for success of course cannot be risked by the psychologist, inasmuch as the man who may be fitted for a task by his mental working dispositions may nevertheless destroy his chances for success by secondary personal traits. He may be dishonest, or dissipated, or a drinker, or a fighter, or physically ill. Finally, we ought not to forget that all such efforts to adjust to one another the psychological traits and the requirements of the work can never have reference to the extreme variations of human traits. The exceptionally talented man knows anyhow where he belongs, and the exceptionally untalented one will be excluded anyhow. The psychological aid in the selection of the fit refers only to the remaining four fifths of mankind for whom the chances of success can indeed be increased as soon as the psychological personal equation is systematically and with scientific exactitude brought into the calculation of the life development. How far a part of this effort will have to be undertaken by the school is a social problem which must be considered from various points of view. Its discussion would lead us beyond the limits of our present inquiry, but it seems probable that the real psychological laboratory experiment in the service of vocational guidance does not belong in the schoolroom itself, but ought to be left to special municipal institutions.

XII

One point here must not be overlooked. The effort to discover the personal structure of the individual in the interest of his vocational chance does not always necessarily involve a direct analysis of his individuality, as material of some value can be gained indirectly. Such indirect knowledge of a man's mental traits may be secured first of all through referring the man to the groups to which he belongs and inquiring into the characteristic traits of those groups. The psychology of human variations gives not only an account of the differences from person to person, but studies no less the psychical inequalities of the races, of the nations, of the ages, of the professions, and so on. If an economic activity demands a combination of mental traits, we may take it for granted that an individual will be fit for the work as soon as we find out that he belongs to a group in which these required mental traits habitually occur. Such a judgment based on group psychology can of course be no more than a mere approach to a solution of the problem, as the psychical qualities may vary strongly in the midst of the group. The special individual may happen to stand at the extreme limit of the group, and the traits which are usually characteristic of it may be very little developed or entirely lacking in his special case. We may know that the inhabitants of a special country are rather alert, and yet the particular individual with whom we have to deal may be clumsy and phlegmatic. The interests of economy will, therefore, be served by such considerations of group psychology only if the employment, not of a single person, but of a large number, is in question, as it is most probable that the average character will show itself in a sufficient degree as soon as many members of the group are involved.

Even in this case the presupposition ought to be that the average characteristics found out with scientific exactitude by statistical and experimental methods, and not that they are simply deduced from superficial impressions. I have found that just this race psychological diagnosis is frequently made in factories with great superficiality. Some of the American industrial centres offer extremely favorable conditions for the comparative study of nationality. I have visited many manufacturing establishments in which almost all workers are immigrants from foreign countries and in which up to twenty different nationalities are represented. The employment officers there easily develop some psychological theories on the basis of which they are convinced that they are selecting the men with especial skill, knowing for each in which department he will be most successful. They consider it settled that for a particular kind of activity the Italians are the best, and for another, the Irish, and for a third, the Hungarians, and for a fourth, the Russian Jews. But as soon as these factory secrets have been revealed, you may be surprised to find that in the next factory a decidedly different classification of the wage-earners is in force. In a gigantic manufacturing concern, I received the definite information that the Swedish laborers are preferable wherever a steady eye is needed, and in another large factory on the same street I was assured that just the Swedes are unfit for such work. Sometimes this diversity of opinion is the result of different points of view. In one factory in which a certain industrial operation is rather dangerous, they told me that they took no southern Europeans, especially no Italians and Greeks, because they are too hasty and careless in their movements, while they gladly filled the places with Irishmen. In a quite similar factory, on the other hand, they had a prejudice against the Irishmen alone for this work, because the Irish laborers are too willing to run a risk and to expose themselves to danger. Probably both psychological observations are on the whole correct, but in the first factory only the one and in the second factory only the other was recognized. Much more thorough statistical inquiries than those which as yet exist, especially as to the actual differences of wages and piecework for wage-earners of various nationalities, would have to furnish a basis for such race psychological statements, until the time arrives when the psychological experiment comes to its own.

In a similar way so far we have to rely on general theories of group psychology when the psychological differences of the sexes are to be reckoned with in economic interests. So long as laboratory methods for individual tests are not usual, the mental analysis of the general groups of men and women must form the background for industrial decisions. To be sure, it is not difficult to emphasize certain mental traits as characteristic of women in general in contrast to men in general, and to relate them to certain fundamental tendencies of their psychophysical organism. As soon as this is done, it is easy theoretically to deduce that certain industrial functions are excellently adapted to the minds of women and that certain others stand in striking antagonism to them. If the employment of large numbers is in question, and average values alone are involved, such a decision on the basis of group psychology may be adequate. In most factories this vague sex psychology, to be sure, usually with a strong admixture of wage questions, suggests for which machines men and for which women ought to be employed. But here again it is not at all improbable that in the case of a particular woman the traditional group value may be entirely misleading and the personality accordingly unfit for the place. Only the subtle psychological individual analysis can overcome the superficial prejudices of group psychology. The situation lies differently when problems of economic policy are before us. Such general policies as, for instance, colonial politics, or immigration politics, or politics concerned with city and rural communities, or with coast and mountain population, will always have to be based on group psychology as far as the economic problems are involved, inasmuch as they refer to the average and not to the individual, differences.

Finally, another indirect scheme to determine the personal qualities needed for economic efficiency may be suggested by the psychology of the typical correlations of human traits. We have seen that group psychology proclaims that a certain individual probably has certain traits because he belongs to this or that nation or to this or that otherwise well-known group. Correlation psychology proclaims that a particular individual possesses or does not possess certain traits because he shows or does not show some other definite qualities. A correlation, for instance, which the commercial world often presupposes, may exist between individual traits and the handwriting. Graphologists are convinced that a certain loop or flourish, or the steepness or the length of the letters, or the position of the i dot, is a definite indication that the writer possesses certain qualities of personality; and if just these qualities are essential requirements for the position, the impression of the handwriting in a letter may be taken as a sufficient basis for appointment. The scientist has reason to look upon this particular case of graphological correlation with distrust. Yet even he may acknowledge that certain correlations exist between the neatness, carefulness, uniformity energy, and similar features of the letter, and the general carefulness, steadiness, neatness, and energy of the personality.

However, the laboratory psychologists nowadays have gone far beyond such superficial claims for correlations of symptoms. With experimental and statistical methods they have gathered ample material which demonstrates the exact degree of probability with which we have a right to expect that certain qualities will occur together. Theoretically we may take it for granted that those traits which are always present together or absent together ultimately have a common mental root. Yet practically they appear as two independent traits, and therefore it remains important to know that, if we can find one of them, we may be sure that the other will exist there too. Inasmuch as the one of the two traits may be easily detected, while the other may be hidden and can be found out only by long careful tests, it would be valuable, indeed, for the employment manager to become acquainted with such correlations as the psychologist may discover: as soon as he becomes aware of the superficially noticeable symptom, he can foresee that the other disposition is most probably present. To give an illustration: in the interest of such measurements of correlations we have studied in the Harvard laboratory the various characteristics of attention and their mutual dependence.[18] We found that typical connections exist between apparently independent features of attention. Persons who have a rather expansive span of attention for acoustical impressions have also a wide span for the visual objects. Persons whose attention is vivid and quick have on the whole the expansive type of attention, while those who attend slowly have a narrow field of attention, and so on. Hence the manifestation of one feature of attention allows us to presuppose without further tests that certain other features may be expected in the particular individual.

The problem of attention, indeed, seems to stand quite in the centre of the field of industrial efficiency. This conviction has grown upon me in my observation of industrial life. The peculiar kind of attention decides more than any mental trait for which economic activity the individual is adapted. The essential point is that such differences of attention cannot be characterized as good or bad; it is not a question of the attentive and of the inattentive mind. One type is not better than another, but is simply different. Two workingmen, not only equally industrious and capable, but also equally attentive, may yet occupy two positions in which they are both complete failures because their attention does not fit the places, and both may become highly efficient as soon as they exchange positions. Their particular types of attention have now found the right places. The one may be disposed to a strong concentration by which everything is inhibited which lies on the mental periphery, the other may have the talent for distributing his attention over a large field, while he is unable to hold it for a long while at one point. If the one industrial activity demands the attentive observation of one little lever or one wheel at one point, while the other demands that half a dozen large machines be simultaneously supervised, all that is necessary is to find the man with the right type of attention for each place. It would be utterly arbitrary to claim that the expansive type of attention is economically more or less valuable than the concentrated type. Both in English and in German we have a long popular series of pamphlets with descriptions of the requirements and conditions for the various occupations to which a boy or a girl may turn, but I have nowhere found any reference to the most essential mental functions such as the particular kind of attention or memory or will. These pamphlets are always cut after the same pattern. Where the detail refers at all to the mental side, it points only to particular knowledge which may be learned in school or trade or work, or to abilities which may be developed by training. But the individual differences which are set by the particular conditions and dispositions of the mind are neglected with surprising uniformity in the vocational literature of all countries. The time seems ripe for at last filling this blank in the consciousness of the nation and in the institutions of the land.

PART II

XIII

We have placed our psychotechnical interest at the service of economic tasks. We therefore had to start from the various economic purposes and had to look backward, asking what ways might lead to these goals. All our studies so far were in this sense subordinated to the one task which ought to be the primary one in the economic world, and yet which has been most ignored. The purpose before us was to find for every economic occupation the best-fitted personality, both in the interest of economic success and in the interest of personal development. Individual traits under this point of view become for us the decisive psychological factors, and experimental psychology had to show us a method to determine those personal differences and their relation to the demands for industrial efficiency. This first goal may be reached with all the means of science, as we hope it will be in the future, or everything may be left to unscientific, haphazard methods as in the past: in any case a second task stands before the community, namely, the securing of the best possible work from every man in his place. Indeed, the nation cannot delay the solution of this second problem until the first has been solved in a satisfactory way. We might even say that the answer to the second question is the more important, the less satisfactory the answer to the first is. If every place in the economic world were filled only by those who are perfectly adapted by their mental traits, it would be much less difficult to get efficient work from everyone. The fact that so many misfits are at work makes it such an urgent necessity to find ways and means by which the efficiency can be heightened.

It must be acknowledged, however, that the problem of the best work is not quite such a clear one as that of the best man. From various standpoints a different answer may be given to the question which kind of work is the best. A capitalistic, profit-seeking egotism may consider the quickest performance, or, if differences of quality are involved, the most skillful performance, the only desirable end. The social reformers, on the other hand, may consider the best work that which combines the greatest and best possible output with the highest possible saving of the organism and the fullest development of the personality. We have emphasized from the start that the practical psychologist as such has not the right to give a decision upon problems of social civilization. He has to accept the economic tasks from the community for which he is working and his impartial service commences only when the goals have been determined. It is not his share to select the ends, but simply to determine the means after the valuable ends have been chosen. As a psychological scientist he has not the right to enter into the arena of different social party fights. Yet we find after all a broad region which seems rather untouched by any conflict of reasonable opinions. A reckless capitalism on the one side and a feeble sentimentality on the other side may try to widen or to narrow the boundaries of this region, but taken all together, a vigorous healthy nation which is eagerly devoted to its work is on the whole in agreement as to the essential economic demands for efficient labor.

Experience, to be sure, shows that great changes in the conditions of work can never enter into the history of civilization without certain disturbances, and that opposition must therefore necessarily arise in certain groups even against such changes as are undoubtedly improvements and advances from the point of view of the whole nation. Such dissatisfaction arose when the factory system was introduced, and it is only natural that some irritation should accompany the introduction of psychological improvements in the methods of work, inasmuch as not a few wage-earners may at first have to lose their places because a small number of men will under the improved conditions be sufficient for the performance of tasks which needed many before. But the history of economics has clearly shown that from the point of view of the whole community such an apparent disturbance has always been only temporary. If the psychologists succeed in fundamentally improving the conditions of labor, the increased efficiency of the individual will promote such an enriched and vivified economic life that ultimately an increase in the number of laborers needed will result. The inquiry into the possible psychological contributions to the question of reinforced achievement must not be deterred by the superficial objection that in one or another industrial concern a dismissal of wage-earners might at first result. Psychotechnics does not stand in the service of a party, but exclusively in the service of civilization.

To begin at the beginning, we may start from the commonplace that every form of economic labor in the workshop and in the factory, in the field and in the mine, in the store and in the office, must first be learned. How far do the experiments of the psychologist offer suggestions for securing the most economic method of learning practical activities? Bodily actions in the service of economic work are taught and learned in hundreds of thousands of places. It is evident that one method of teaching must reach the goal more quickly and more reliably than another. Some methods of teaching must therefore be economically more advantageous, and yet on the whole the methods of teaching muscular work are essentially left to chance. It is indeed not difficult to observe how factory workers or artisans have learned the same complex motion according to entirely different methods. The result is that they carry out the various partial movements in a different order, or with different auxiliary motions, or in different positions, or in a different rhythm, or with different emphasis, simply because they imitate different teachers, and because no norm, no certainty as to the best methods for the teaching, has been determined. But the process of learning is still more fluctuating and still more dependent upon chance than the process of teaching. The apprentice approaches the instruction, in any chance way, and the beginner usually learns even the first steps with a psychophysical attitude which is left to accident. An immense waste of energy and a quite anti-economic training in unfit movements is the necessary result.

The learning of the elements of school knowledge in the classroom in earlier times proceeded after exactly such chance methods. Any one who knew how to read, write, and calculate felt himself prepared to pour reading, writing, and arithmetic into the unprotected children. Methods which are based on scientific examination of the psychophysical process of reading and writing were not at the disposal of the schools, and exact results from comparative studies of pedagogical methods had not been secured. The last few decades have created an entirely new foundation for enlightened school work. The experimental investigations of pedagogical psychology have determined exactly how the consciousness of the child reacts on the various methods of teaching and have built up a real systematic economic learning. All which was left to dilettantic caprice has been transformed into more or less definite standard forms. For instance, the old scheme of teaching reading by the alphabet method is practically eliminated from our modern schools. It is clear that this learning of the names of the single letters as a starting-point for the reading of words was not only a wasting of time and energy, but an actual disturbance in the development of the reading process in the older generation. As those names of the letters do not occur at all in the words to be read, but only their sounds, what had been learned in seeing the single letters had to be inhibited in pronouncing the whole word. It seems not too much to say that the learning of industrial activities on the whole still stands on the level of such alphabet methods, and this cannot be otherwise, as the real problem, namely, the systematic investigation of the psychophysical activities involved, has never been brought into the psychological laboratory.

The pedagogical experiment has shown clearly enough that the subjective feeling of easier or quicker learning may be entirely unreliable and misleading. If the task is to learn a page by heart, we may proceed after many different methods. We may learn very small fractions of the text, repeating only a few words, or we may read whole paragraphs every time; we may repeat the whole material again and again, or we may put in long periods of rest after a few repetitions; we may frequently recite it from memory and have some one to prompt us; we may give our attention especially to the meaning of the words, or merely to the sounds, or we may introduce any number of similar variations. Now the careful experiment shows that of two such methods one which appears to us the better and more appropriate in learning, perhaps even as the easier and more comfortable, may prove itself the less efficient one in the practical result. The psychology of learning, which won its success by introducing meaningless syllables as experimental material, has slowly determined the most reliable methods for impressing knowledge on memory. Where such results have once been secured, it would surely be a grave mistake simply to stick to the methods of so-called common sense and to leave it to the caprice of the individual teacher to decide what method of learning he will suggest to his pupils. The best method is always the only one which should be considered. The psychology of economic work must aim toward similar goals. We must secure a definite knowledge as to the methods by which a group of movements can best be learned. We must understand what value is to be attached to the repetitions and to the pauses, to the imitations and to the special combinations of movements, to the exercise in parts of the movements, to the rhythm of the work, and to many similar influences which may shape the learning process.

The simplest aspect, that of the mere repetition of the movement, has frequently been examined by psychophysicists. The real founder of experimental psychology, Fechner, showed the way; he performed fatiguing experiments with lifted dumb-bells. Then came the time in which the laboratories began to make a record of the muscular activities with the help of the ergograph, an instrument with which the movements of the arm and the fingers can easily be registered on the smoked surface of a revolving drum. The subtlest variations of the activity, the increase and decrease of the psychomotor impulse, the mental fatigue, can be traced exactly in such graphic records. This psychomotor side of the process, and not the mere muscle activity as such, is indeed the essential factor which should interest us. The results of exercise are a training of the central apparatus of the brain and not of the muscular periphery. The further development of those experiments soon led to complex questions, which referred not only to the mere change in the motor efficiency, but to the learning of particular groups of movements and to the influences on the exactitude and reliability of the movements. The purely mental factors of the will-impulse, especially the consciousness of the task, came into the foreground. These experiences of the scientists concerning the influences of training, the mechanization of repetition, and the automatization of movements have been thoroughly discussed by a brilliant political economist[19] as an explanation of certain industrial facts, but they have not yet practically influenced life in the factory.

The nearest approach from the experimental side to the study of the effect of training in actual industrial tasks may be found in certain laboratory investigations which refer to the learning of telegraphing, typewriting, and so on. For instance, we have a careful study[20] of the progress made in learning telegraphy, both as to the transmitting of the telegrams by the key movement and the receiving of the telegrams by the ear. It was found that the rapidity of transmitting increases more rapidly and more uniformly than the rapidity of receiving. But while the curve of the latter rises more slowly and more irregularly, it finally reaches the greater height. The ability in transmitting, represented by a graphic record, shows an ascent which corresponds to the typical, steady curve of training. In the receiving curve, on the other hand, we find not far from the beginning a characteristic period during which no progress whatever can be noticed, and this is also repeated at a later stage. The psychological analysis shows that the increase of ability in the receiving of telegrams depends upon the development of a complex system of psychophysical habits. The periods in which the curve does not ascend represent stages of training in which the elementary habits are almost completely formed, but have not become sufficiently automatic. The attention is therefore not yet ready to start habits of a higher order. The lowest correlation refers to the single letters, after that to the syllables and words. As soon as the apprentice has reached this point, he stops, because he must learn to master more and more new words until his telegraphic vocabulary is large enough to make it possible for him to turn his consciousness to whole groups of words at once. Only when this new habit has been made automatic by a training of several months can he advance to a level at which whole groups of words are perceived as telegraphic units. A time follows in which this mastery of whole phrases advances rapidly, until a new period of rest comes, from which, only after years and often quite suddenly, a last new ascent can be noticed. Instead of concentrating the attention with conscious strain on single phrases, the operator progresses to a perfect liberty in which whole sentences are understood automatically.

We also have a model experimental research into the psychological conditions of learning in the case of writing on a typewriter.[21] By electrical connections between the typewriting machine and a system of levers which registered their movements on the rotating drum of a kymograph, graph, each striking of a key, each completion of a word, or of a line, could be recorded in exact time-relations. Each glance at the copy was also registered. It was found that the process of learning consisted first of a continuous simplification of the cumbersome methods with which the beginner commences. A steady elimination of unfit movements, a selection, a reorganization, and finally, a combination of psychophysical acts to impulses of higher order, could be traced exactly. Here, too, the curve of learning at first rises quickly and then more and more slowly. Of course the usual fluctuations in the growth of the ability can also be found, and above all the irregular periods of rest in which the learning itself does not progress, for some of these so-called plateaus which lie between the end of one ascent and the beginning of the next may cover a month and more. At the beginning we have the elementary association between the single letter and the position of the corresponding key, but soon an immediate connection between the visual impression of the whole syllable or the whole word and the total group of movements necessary to strike the keys for it is developed. The more the ability grows, the more these psychical impulses of higher order become organized without conscious intention. The study shows that this development of higher habits has already begun before the lower habits are fully settled.

How far the special training involves at the same time a general training which could be of advantage for other kinds of labor has not yet been studied at all with reference to industrial technique. There we are still completely dependent upon certain experiences in the field of experimental pedagogy, and upon certain statistics, for instance, in the textile industry. Many patient investigations, with every independent group of apparatus and machines, may be necessary before psychotechnics will be able to supply industry with reliable advice for teaching and learning. Nor have we the least right hastily to carry over the results from one group of movements to another. Even where superficially a certain similarity between the technical factors exists, the psychophysical conditions may be essentially different. In the two cases mentioned, for instance, telegraphing and typewriting, the chief factor seems the same, as in both cases the aim is to make the quickest possible finger movements for purposes of signals; and yet it is not surprising that the development of the ability from the beginnings to the highest mastery is rather unlike, as all the movements in telegraphing are performed with the same finger, while in typewriting the chief trait is the organization of groups from the impulses to all ten fingers. At least it is certain that learning always means far more than a mere facilitation of the movement by mechanical repetition, and this is true of the simplest handling of the tools in the workshop, of the movements at the machine in the factory, and of the most complex performances at the subtlest instruments. The chief factor in the development is always the organization of the impulses by which the reactions which are at first complicated become simplified, later mechanized, and finally synthesized into a higher group which becomes subordinated to one simple psychical impulse. The most reliable and psychophysically most economic means for this organization will have to be studied in the economic psychological laboratories of the future for every particular technique. Then only can the enormous waste of psychical energy resulting from haphazard methods be brought to an end.

A problem which is still too little considered in industrial life is the mutual interference of acquired technical activities. If one connected series of movements is well trained by practice, does it become less firmly fixed, if another series is studied in which the same beginning is connected with another path of discharge? I approached this psychophysical question of learning by experiments which I carried on for a long while with variations of ordinary habits of daily life, asking whether a habit associated with a certain sensory stimulus can function automatically while dispositions for a different habit, previously acquired, remain in the psychophysical system. For instance, I was accustomed to carry my watch in my left-hand vest pocket. For a week I carried it in the right-hand pocket of my trousers and recorded every case in which I first automatically made the movement to the vest. After some time the movement to the right-hand pocket became entirely automatic. When it was sufficiently fixed, I again put the watch in the left-hand vest pocket and recorded how often I unconsciously grasped at the right side when I wanted to see what time it was. As soon as the vest pocket movement had again become fixed, I went back to the right-hand trousers pocket. And so I alternated for a long while, always changing only after reaching complete automatism. But the results in this case and in other similar experiments which I carried on showed that the new automatic connection did not extinguish the after effects of the previous habit. With every new change the number of wrong movements became smaller and smaller, and finally a point was reached at which the dispositions for both movements were equally developed so that no wrong movements occurred when the watch was put into the new position.[22]

This problem has been followed up very recently in a valuable investigation at Columbia University,[23] in which various habits of typewriting and of card-sorting were acquired and studied in their mutual interference. These very careful experiments also show that when two opposing associations are alternately practiced, they have an interference effect on each other, but that the interference grows less and less as the practice effect becomes greater. The interference effect is gradually overcome and both opposing associations become automatic, so that either of them can be called up independently without the appearance of the other. Many details of the research suggest that this whole group of interference problems deserves the most careful attention by those who would practically profit from increased industrial efficiency.

Finally, in the experimental study of the problem of technical learning, we cannot ignore the many side influences which may hasten or delay, improve or disturb, the acquisition of industrial skill. In the Harvard laboratory, for instance, we are at present engaged in an investigation which deals with the influence of feelings on the rapidity with which new movement coördinations are mastered.[24] In order to have unlimited comparable material a very simple technical performance is required, namely, the distribution of the 52 playing-cards into 52 boxes. Labels on the boxes indicate changing combinations for the distribution to be learned. We examine, on the one side, the influence of feelings of comfort or of discomfort on the learning of the new habit, these feeling states being produced by external conditions, such as pleasant or unpleasant sounds, odors, and so on. On the other side we trace the effects of those feelings which arise during the learning process itself, such as feelings of satisfaction with progress, or disappointment, or discomfort, or disgust or joy in the activity.

XIV

Teaching and learning represent only the preliminary problem. The fundamental question remains, after all, how the work is to be done by those who have learned it in accordance with the customs of the economic surroundings and who are accordingly already educated and trained for it. What can be done to eliminate everything which diminishes and decreases efficiency, and what remains to be done to reinforce it. Such influences are evidently exerted by the external technical conditions, by variations of the activity itself, and by the play of the psychical motives and counter-motives. It must seem as if only this last factor would belong in the realm of psychology, but the technical conditions, of which the machine itself is the most important part, and the bodily movements also have manifold relations to the psychical life. Only as far as these relations prevail has the psychologist any reason to study the problem. The purely physical and economic factors of technique do not interest him at all, but when a technical arrangement makes a psychophysical achievement more difficult or more easy, it belongs in the sphere of the psychologist, and just this aspect of the work may become of greatest importance for the total result. In all three of these directions, that is, with reference to the technical, to the physiological, and to the purely psychical, the scientific management movement has prepared the way. The engineers of scientific management recognized, at least, that no part of the industrial process is indifferent, even the apparently most trivial activity, the slightest movement of arm or hand or leg, became the object of their exact measurement. The stopwatch which measures every movement in fractions of a second has become the symbol of this new economic period. As long as special psychological experiments in the service of industrial psychology are still so exceptional, it may, indeed, be acknowledged that the practical experiments in the service of scientific management have come nearest to the solution of these special psychotechnical problems.

To proceed from without toward the centre, we may begin our review with the physical technique of the working conditions and its relations to the mind. Tue history of technique shows on every page this practical adjustment of external labor conditions to the psychophysical necessities and psychophysical demands. No machine with which a human being is to work can survive in the struggle for technical existence, unless it is to a certain degree adapted to the human nerve and muscle system and to man's possibilities of perception, of attention, of memory, of feeling, and of will. Industrial technique with its restless improvements has always been subordinated to this postulate. Every change which made it possible for the workingman to secure equal effects with smaller effort or to secure greater or better effects with equal effort counted as an economic gain, which was welcome to the market. For instance, throughout the history of industry we find the fundamental tendency to transpose all activities from the great muscles to the small muscles. Any activity which is performed with the robust muscles of the shoulder when it can be done with the lower arm, or labor which is demanded from the muscles of the lower arm when it can just as well be carried out by the fingers, certainly involves a waste of psychophysical energy. A stronger psychophysical excitement is necessary in order to secure the innervation of the big muscles in the central nervous system. This difference in the stimulation of the various muscle groups has been of significant consequence for the differentiation of work throughout the development of mankind.[25] Labor with the large muscles has, for these psychophysical reasons, never been easily combined with the subtler training of the finer muscles. Hence a social organization which obliged the men to give their energy to war and the hunt, both, in primitive life, functions of the strongest muscles, made it necessary for the domestic activities, which are essentially functions of the small muscles, to be carried out by women. The whole history of the machine demonstrates this economic tendency to make activities dependent upon those muscles which presuppose the smallest psychophysical effort. It is not only the smaller effort which gives economic advantage to the stimulation of the smaller muscles, but the no less important circumstance that the psychophysical after-effect of their central excitement exerts less inhibition than the after-effect of the brain excitement for the big muscles.

But we must not overlook another feature in the development of technique. The machines have been constantly transformed in the direction which made it possible to secure the greatest help from the natural coördination of bodily movements. The physiological organization and the psychophysical conditions of the nervous system make it necessary that the movement impulses flow over into motor side channels and thus produce accessory effects without any special effort. If a machine is so constructed that these natural accessory movements must be artificially and intentionally suppressed, it means, on the one side, a waste of available psychophysical energy, and on the other side it demands a useless effort in order to secure this inhibition. The industrial development has moved toward both the fructification of those side impulses and the avoidance of these inhibitions. It has adjusted itself practically to the natural psychical conditions. Ultimately it is this tendency which shaped the technical apparatus for the economic work until the muscle movements could become rhythmical. The rhythmical activity necessarily involves a psychophysical saving and this saving has been instinctively secured throughout the history of civilization. All rhythm contains a repetition of movement without making a real repetition of the psychophysical impulse necessary. In the rhythmical activity a large part of the first excitement still serves for the second, and the second for the third. Inhibitions fall away and the mere after-effect of each stimulus secures a great saving for the new impulse. The history of the machine even indicates that the newer technical development not only found the far-reaching division of labor already in the workshops of earlier centuries, but a no less far-reaching rhythmization of the labor in fine adaptation to the needs of the psychophysical organism, long before the appearance of the machines. The beginnings of the machine period frequently showed nothing but an imitation of the rhythmical movements of man.[26] To be sure, the later improvements of the machine have frequently destroyed that original rhythm of man's movement, as the movement itself, especially in the electric machines, has become so quick that the subjective rhythmical experience has been lost. Moreover, the rhythmical horizontal and vertical movements were for physical reasons usually replaced by uniform circular movements. But even the most highly developed machine demands human activity, for instance, for the supplying with material; and this again has opened new possibilities for the adjustment of technical mechanism to the economic demand for rhythmical muscle activity. The growth of technical devices has thus been constantly under the control of psychological demands, in spite of the absence of systematic psychological investigations. But the decisive factor was, indeed, that these psychological motives always remained in the subconsciousness of civilization. The improvements were consciously referred to the machine as such, however much the practical success was really influenced by the degree of its adjustment to the mental conditions of the workingmen. The new movements of scientific management and of experimental psychology aim toward bringing this adaptation consciously into the foreground and toward testing and studying systematically what technical variations can best suit the psychophysical status of man.

Those who are familiar with the achievements of scientific management remember that by no means only the complicated procedures on a high level are in question. The successes are often the most surprising where the technique is old, and where it might have been imagined that the experiences of many centuries would have secured through mere common sense the most effective performance. The best-known case is perhaps that of the masons, which one of the leaders of the scientific management movement has studied in all its details.[27] The movements of the builders and the tools which they use were examined with scientific exactitude and slowly reshaped under the point of view of psychology and physiology. The total result was that after the new method 30 masons completed without greater fatigue what after the old methods it would have taken 100 masons to do, and that the total expense for the building was reduced to less than a half in spite of the steady increase of the wages of the laborers. For this purpose it was necessary that exact measurements be made of the height at which the bricks were lying and of the height of the wall on which they must be laid, and of the number of bricks which should be carried to the masons at once. He studied how the trowel should be shaped and how the mortar should be used and how the bricks should be carried to the bricklayers. In short, everything which usually is left to tradition, to caprice, and to an economy which looks out only for the most immediate saving, was on the basis of experiments of many years replaced by entirely new means and tools, where nothing was left to arbitrariness. Yet these changes did not demand any invention or physically or economically new ideas, but merely a more careful adaptation of the apparatus to the psychological energies of the masons. The new arrangement permitted a better organization of the necessary bodily movements, fatigue was diminished, the accessory movements were better fructified, fewer inhibitions were necessary, a better playing together of the psychical energies was secured.

The students of scientific management stepped still lower in the scale of economic activity. There is no more ordinary productive function than shoveling. Yet in great establishments the shoveling of coal or of dirt may represent an economically very important factor. It seems that up to the days of scientific management, no one really looked carefully into the technical conditions under which the greatest possible economic effect might be reached. Now the act of shoveling was approached with the carefulness with which a scholar turns to any subtle process in his laboratory. The brilliant originator of the scientific management movement, who carried out these investigations[28] in the great Bethlehem Steel Works, where hundreds of laborers had to shovel heavy iron ore or light ashes, found that the usual chance methods involve an absurd economic waste. The burden was sometimes so heavy that rapid fatigue developed and the movements became too slow, or the lifted mass was so light that the larger part of the laborer's energies remained unused. In either case the final result of the day's work must be anti-economic. He therefore tested with carefully graded experiments what weight ensured the most favorable achievement by a strong healthy workingman. The aim was to find the weight which would secure with well-arranged pauses the maximum product in one day without over-fatigue. As soon as this weight was determined, a special set of shovels had to be constructed for every particular kind of material. The laborers were now obliged to operate with 10 different kinds of shovels, each of such a size that the burden always remained an average of 21 pounds for any kind of material. The following step was an exact determination of the most favorable rapidity and the most perfect movement of shoveling, the best distribution of pauses, and so on, and the final outcome was that only 140 men were needed where on the basis of the old plan about 500 laborers had been engaged. The average workingman who had previously shoveled 16 tons of material, now managed 59 tons without greater fatigue. The wages were raised by two thirds and the expenses for shoveling a ton of material were decreased one half This calculation of expenses included, of course, a consideration of the increased cost for tools and for the salaries of the scientific managers.

Whoever visits factories in which the new system has been introduced by real specialists must be surprised, indeed, by the great effects which often result from the better psychophysical adaptation of the simplest and apparently most indifferent tools and means. As far as the complicated machines are concerned, we are accustomed to a steady improvement by the efforts of the technicians and we notice it rather little if the changes in them are introduced for psychological instead of the usual physical reasons. But the fact that even the least complicated and most indifferent devices can undergo most influential improvements, as soon as they are seriously studied from a psychological point of view, remains really a source for surprise. Sometimes no more is needed than a change in the windows or in the electric lamps, by which the light can fall on the work in a psychologically satisfactory way; sometimes long series of experiments have to be made with a simple hammer or knife or table. Often everything must be arranged against the wishes of the workingmen, who feel any deviation from the accustomed conditions as a disturbance which is to be regarded with suspicion. In one concern I heard that the scientific manager became convinced that all the working-chairs for the women were too low and that the laborers therefore had to hold their arms in a psychophysically unfavorable position during the handling of the apparatus. All were strongly opposed to the introduction of higher chairs. The result was that the manager arranged for the chairs to be raised a few millimeters every evening, without the knowledge of the working-women, as soon as the factory was empty. After a few weeks the chairs had reached the right height without those engaged in the work having noticed it at all. The outcome was a decided increase of efficiency.

But the most rational scheme will after all be to prepare for such arrangements of tools and apparatus by systematic experiments in the psychological laboratory. The subtlety of such investigations will lead far beyond the point which is accessible to the attempts of scientific management. Exact experiments on attention, for instance, will have to determine how the various parts of the apparatus are to be distributed best in space if the laborer must keep watch for disturbances at various places. Only the laboratory experiment can find the most favorable speed of the machine or can select the muscles to which the mind can send the most effective impulses. The construction of the machine must then be adapted to such results. In the Harvard laboratory, for instance, a practical question led us to examine which fingers would allow the quickest alternation of key movements.[29] If any two of the ten fingers perform for ten seconds the quickest possible alternation of motion, as in a trill, the experiment can demonstrate exactly the differences between the various combinations of fingers and the individual fluctuations for these differences. With an electrical registration of the movements of the alternating fingers we studied in hundredths of a second the time for the motions of two hands and of fingers of the same hand, in order to adjust the keys of a certain machine to the most favorable impulses.

We approach this group of problems from another side when we test the relations of various kinds of machines to various mental types. Psychologists have studied, for example, the various styles of typewriting machines.[30] From a purely commercial point of view the merits of one or another machine are praised as if they were advantageous for every possible human being. The fact is that such advantages for one may be disadvantages for another on account of differences in the mental disposition. One man may write more quickly on one, another on another machine. As every one knows, the chief difference is that of the keyboard and that of the visible or invisible writing. Machines like the Remington machine work with a shift key; that is, a special key must be pressed when capital letters are to be written. Other machines like the Oliver even demand double shifting, one key for the capital letters, and one for the figures, and so on. On the other hand, machines like the Smith Premier have no shift key, but a double keyboard. It is evident that both the shift-key arrangement and the double keyboard have their particular psychological advantages.

The single alphabet demands much less from the optical memory, and the corresponding motor inner attitude of consciousness is adjusted to a smaller number of possibilities. But the pressure on the shift key, which goes with the single alphabet, is not only a time-wasting act; from the psychological point of view it is first of all a very strong interruption of the uniform chain of impulses. If the capital and small letters are written for a minute alternatingly with the greatest possible speed, the experiment shows that the number of letters for the machine with the double alphabet is about three times greater than for the machine with simple alphabet and shift key. Both systems accordingly have their psychological advantages and disadvantages. Human beings of distinct visual ideational type or of highly developed motor type will prefer the double alphabet, provided, of course, that the touch system of writing is learned, and this will be especially true if their inner attitude is easily disturbed by interruptions. But those who have a feebly developed optical mental centre and who have small ability for the development of complex motor habits will be more efficient on the machines with the single alphabet, especially if their nervous system is little molested by interruptions and thus undisturbed by the intrusion of the shift key act.

In a similar way the visibility of the writing will be for certain individuals the most valuable condition for quick writing, while for others, who depend less upon visual support, it may mean rather a distraction and an interference with the speediest work. The visible writing attracts the involuntary attention, and thus forces consciousness to stick to that which has been written instead of being concentrated on that which is to be produced by the next writing movements. The operator himself is not aware of this hindrance. On the contrary, the public will always be inclined to prefer the typewriters with visible writing, because by a natural confusion the feeling arises that the production of the letter is somewhat facilitated, when the eye is coöperating, just as in writing with a pen we follow the lines of the written letter. But the situation lies differently in the two cases. When we are writing with a pen, the letter grows under our eyes, while in the machine writing we do not see any part of the letter until the whole movement which produces the single letter is finished. By such a misleading analogy many a man is led to prefer the typewriter with visible writing, while he would probably secure a greater speed with a machine which does not tempt him to attend the completed letters, while his entire attention ought to belong to the following letters.

These last observations point to another psychological aspect of the machine and of the whole technical work, namely, their relations to the impressions of the senses. The so-called dynamogenic experiments of the psychological laboratory have demonstrated what a manifold influence flows from the sense-impressions to the will-impulses. If the muscle contraction of a man's fist is measured, the experiment shows that the strongest possible pressure may be very different when the visual field appears in different colors, or tones of different pitch or different noises are stimulating the ear, and so on. As yet no systematic experiments exist by which such results can be brought into relation to the sense-stimuli which reach the laborer during his technical work. The psychophysical effect of colors and noises has not been fructified at all for industrial purposes. The mere subjective judgment of the workingman himself cannot be acknowledged as reliable in such questions. The laborer, for instance, usually believes that a noise to which he has become accustomed does not disturb him in his work, while experimental results point strongly to the contrary. In a similar way the effect of colored windows may appear indifferent to the workmen, and yet may have considerable influence on his efficiency. Numberless performances in the factory are reactions on certain optical or acoustical or tactual signals. Both the engineer and the workman are satisfied if such a signal is clearly perceivable. The psychological laboratory experiment, however, shows that the whole psychophysical effect depends upon the character of the signal; a more intense light, a quicker change, a higher tone, a larger field of light, a louder noise, or a harder touch may produce a very different kind of reaction.

With a careful time-measurement of the motions, it can often be directly traced how purely technical processes in the machine itself influence and control the whole psychical system of impulses in the man. I observed, in a factory, for instance, the work at a machine which performed most of its functions automatically. It had to hammer fine grooves into small metal plates. A young laborer stood before every such machine, took from a pile, alternately from the right and from the left, the little plates to be serrated, placed them in the machine, turned a lever to bring the hammer into motion, and then removed the serrated plates. The speed of the work was dependent upon the operative, as he determined by his lever movement the instant at which the automatic serrating hammer should be released. The man's activity demanded 9 independent movements. I found that those who worked the most quickly were able to carry out this labor for hours at a uniform rapidity of 4 to 4-1/2 second for those 9 movements. But the time-measurement showed that even these fastest workers were relatively slow in the first 5 movements which they made while the machine stood quiet, and that they reached an astonishing quickness of movement in the 4 last actions during which at the same time the serrating hammer in bewildering rapidity was beating on the plate with sharp loud cracks. The hammer reinforced the energy of the young laborers to an effectiveness which could never have been attained by mere voluntary effort.

Often the simplicity or complication of the stimulus may be decisive in importance, and this also holds true where the most elementary reactions are involved, for instance, the mere act of counting which enters into many industrial functions. Experiments carried on in my laboratory[31] have shown that the time needed to count a certain number of units becomes longer as soon as the units themselves become more complicated. Their inner manifoldness exerts a retarding influence on the eye as it moves from one figure to another. A certain psychical inhibition arises; the mind is held back by the complexity of the impression and cannot proceed quickly enough to the next. Psychologically no less important is the demand that the external technical conditions so far as they influence consciousness, should remain as far as possible the same, if the same psychical effect is desired, because then only can a perfectly firm connection between stimulus and movement be formed. In technical life this demand is much sinned against. A typical case is that of the signals for which the engineer on the locomotive has to watch. In the daytime the movable arms of the semaphore indicate by their horizontal, oblique, or vertical position whether the tracks are clear. At night-time, on the other hand, the same information reaches him by the different colors of the signal lanterns. From a psychical point of view it is probable that the safety of the service would be increased if an unchangeable connection between signal and movement were formed. It would be sufficient for that purpose if the color signals at night were given up and were replaced by horizontal, oblique, or vertical lines of white light or rows of points. Successful experiments of this kind have been carried on by psychologists in the service of this railroad problem.[32]