The necessary condition for carrying out the experiments with this apparatus is a careful, quiet, practical explanation of the device. The experiment must not under any circumstances be started until the subject completely understands what he has to do and for what he has to look out. For this purpose I at first always show the man one card outside of the apparatus and explain to him the differences between the black and the red figures, and the counting of the steps, and show to him in a number of cases how some red figures do not reach the track, how others go beyond the track, and how some just land in danger on the track. As soon as he has completely understood the principle, we turn to the apparatus and he moves the window slowly over a test card, and tries to find the dangerous spots, and I turn his attention to every case in which he has omitted one or has given an incorrect letter. We repeat this slowly until he completely masters the rules of the game. Only then is he allowed to start the experiment. I have never found a man with whom this preparation takes more than a few minutes.

After developing this method in the psychological laboratory, I turned to the study of men actually in the service of a great electric railway company which supported my endeavors in the most cordial spirit. In accordance with my request, the company furnished me with a number of the best motormen in its service, men who for twenty years and more had performed their duties practically without accidents, and, on the other hand, with a large number of motormen who had only just escaped dismissal and whose record was characterized by many more or less important collisions or other accidents. Finally, we had men whose activity as motormen was neither especially good nor especially bad.

The test of the method lies first in the fact that the tried motormen agreed that they really pass through the experiment with the feeling which they have on their car. The necessity of looking out in both directions, right and left, for possible obstacles, of distinguishing those which move toward the track from the many which move along the track, the quick discrimination among the various rates of rapidity, the steady forward movement of the observation point, the constant temptation to give attention to those which are still too far away or to those which are so near that they will cross the track before the approach of the car, in short, the whole complex situation with its demands on attention, imagination, and quick adjustment, soon brings them into an attitude which they themselves feel as identical with that in practical life. On the other hand, the results show a far-reaching correspondence between efficiency in the experiment and efficiency in the actual service. With a relatively small number of experiments this correspondence cannot be expected to be complete, the more as a large number of secondary features must enter which interfere with an exact correlation between experiment and standing in the railway company. We must consider, for instance, that those men whom the company naturally selects as models are men who have had twenty to thirty years of service without accidents, but consequently they are rather old men, who no longer have the elasticity of youth and are naturally less able to think themselves into an artificial situation like that of such an experiment, and who have been for a long time removed from contact with book work. It is therefore not surprising, but only to be expected, that such older, model men, while doing fair work in the test, are yet not seldom far surpassed by bright, quick, young motormen who are twenty years younger, even though they are not yet ideal motormen. Moreover, the standing in the company often depends upon features which have nothing to do with the mental make-up of the man, while the experiment has to be confined to these mental conditions which favor accidents. It is quite possible that a man may happen to experience a slight collision, even though no conditions for the accident were lying in his mental make-up. But we may go still further. The experiment refers to those sides of his mind which make him able to foresee the danger points, and that is decidedly the most essential factor and the one from which most can be hoped for the safety of the public. But this does not exclude the possibility that some other mental traits may become causes of accidents. The man may be too daring and may like to run risks, or he may still need discipline, or he may not be sufficiently acquainted with the local conditions. Any such secondary factors may cause some slight accidents with the man who shows rather fair results in the experimental test of his foresight. Finally, we must not forget that some men enter into such tests under a certain nervous tension and therefore may not show so well at the very first test as their mental equipment should allow. Hence it is decidedly desirable not to rely on the first test, but to repeat it. If those various interferences are taken into account, the correspondence between efficiency and the results of the tests is fairly satisfactory. It justified me in proposing that the experiments be continued and in regarding it as quite possible that later tests on the basis of this principle may be introduced at the employment of motormen.

A difficulty is presented by the valuation of the numerical results. The mere number of omissions alone cannot be decisive, as it is clear that no intelligent man would make any omissions if he should give an unlimited amount of time to it; for instance, if he were to spend fifteen minutes on those 12 cards. But this is the same thing as to say that a motorman would not run over any one if he were to drive his car one mile in an hour. The practical problem is to combine the greatest possible speed with the smallest number of oversights and both factors must therefore be considered. The subject who makes relatively many mistakes but uses a very short time must be acknowledged to be as good as the man who makes fewer mistakes but takes a longer time. In the results which I have gathered in experiments with motormen, no one has gone through those 12 cards in a shorter time than 140 seconds, while the longest time was 427 seconds. On the other hand, no one of the motormen made less than 4 omissions, while the worst ones made 28 omissions. I abstract from one extreme case with 36 omissions. On the whole, we may say that the time fluctuates between 180 and 420, the mistakes between 4 and 28. The aim is to find a formula which gives full value to both factors and makes the material directly comparable in the form of one numerical value instead of the two. If we were simply to add the number of seconds and the number of omissions, the omissions would count far too little, inasmuch as 10 additional omissions would then mean no more than 10 additional seconds. On the other hand, if we were to multiply the two figures the omissions would mean by far too much, as the transition from 4 mistakes to 8 mistakes would then be as great a change as the transition from 200 to 400 seconds, that is, from the one extreme of time to the other. Evidently we balance both factors if we multiply the number of omissions by 10 and add them to the number of seconds. The variations between 4 and 28 omissions are 24 steps, which multiplied by 10 correspond to the 240 steps which lie between 180 and 420 seconds. On that basis any additional 50 seconds would be equal to 5 additional omissions. If of two men one takes 100 seconds less than his neighbor, he is equal to him in his ability to satisfy the demands of the service, if he makes 10 mistakes more.

On the basis of this calculation I find that the old, well-trained motormen come to a result of about 450, and I should consider that an average standard. This would mean that a man who uses 400 seconds would not be allowed to make more than 5 omissions, in 350 seconds not more than 10, in 300 not more than 15, in 250 not more than 20, under the condition that these are the results of the first set of experiments. Where there are more than 20 omissions made, mere quickness ought not to be allowed as a substitute. The man who takes 150 seconds and makes 30 mistakes would come up to the same standard level of 450. Yet his characteristics would probably not serve the interests of the service. He would speed up his car and would make better time than any one else, but would be liable to accidents. I should consider 20 mistakes with a time not longer than 250 as the permissible maximum. Among the younger motormen whom I examined, the best result was 290, in which 270 seconds were used and only 2 omissions made. Results below 350 may be considered as very good. One man, for instance, carried out the experiment in 237 seconds with 11 mistakes, which gives the result 347. From 350 to 450 may be counted as fair, 450 to 550 as mediocre, and over 550 as very poor. In the case of old men, who may be expected to adjust themselves less easily to artificial experiments, the limits may be shifted. If the experiments are made repeatedly, the valuation of the results must be changed accordingly. The training of the men in literary and mathematical work or in experimentation may be considered, as our experiments have shown that highly educated young people with long training in experimental observations can pass through the test much more quickly than any one of the motormen could. Among the most advanced graduate students who do research work in my Harvard laboratory there was no one whose result was more than 275, while, as I said, among all the motormen there was no one whose result was less than 290. The best result reached was by a student who passed through the test in 223 seconds with only 1 mistake, the total therefore being 233. Next came a student who did it in 215 seconds with 3 mistakes, total, 245; then in 228 seconds with 2 omissions, total, 248, and so on.

I recapitulate: With men on the educational level and at the age that comes in question for their first appointment in the service of an electric railway company, the test proposed ought to be applied according to this scheme. If they make more than 20 mistakes, they ought to be excluded; if they make less than 20 mistakes, the number of omissions is to be multiplied by 10 and added to the number of seconds. If the sum is less than 350, their mental fitness for the avoidance of accidents is very high, between 350 and 450 fair, and more than 550 not acceptable under any conditions. I submit this, however, with the emphasis on my previous statement that the investigation is still in its first stage, and that it will need a long cooeperation between science and industry in order to determine the desirable modifications and special conditions which may become necessary in making the employment of men partly dependent upon such psychological tests. There can be no doubt that the experiments could be improved in many directions. But even in this first, not adequately tested, form, an experimental investigation of this kind which demands from each individual hardly 10 minutes would be sufficient to exclude perhaps one fourth of those who are nowadays accepted into the service as motormen. This 25 per cent of the applicants do not deserve any blame. In many other occupations they might render excellent service; they are neither careless nor reckless, and they do not act against instructions, but their psychical mechanism makes them unfit for that particular combination of attention and imagination which ought to be demanded for the special task of the motorman. If the many thousands of injury and the many hundreds of death cases could be reduced by such a test at least to a half, then the conditions of transportation would have been improved more than by any alterations in the technical apparatus, which usually are the only objects of interest in the discussion of specialists. The whole world of industry will have to learn the great lesson, that of the three great factors, material, machine, and man, the man is not the least, but the most important.



IX

EXPERIMENTS IN THE INTEREST OF SHIP SERVICE

Where the avoidance of accidents is in question, the test of a special experimental method can seldom be made dependent upon a comparison with practical results, as we do not want to wait until the candidate has brought human life into danger. The ordinary way of reaching the goal must therefore be an indirect one in such cases. For the study of motormen the conditions are exceptionally favorable, as hundreds of thousands of accidents occur every year, but another practical example may be chosen from a field where it is, indeed, impossible to correlate the results with actual misfortunes, because the dangerous situations occur seldom; and nevertheless on account of their importance they demand most serious study. I refer to the ship service, where the officer on the bridge may bring thousands into danger by one single slip of his mind. I turn to this as a further concrete illustration in order to characterize at once the lengths to which such vocational studies may advance.

One of the largest ship companies had approached me—long before the disaster of the Titanic occurred—with the question whether it would not be possible to find psychological methods for the elimination of such ship officers as would not be able to face an unexpected suddenly occurring complication. The director of the company wrote to me that in his experience the real danger for the great ships lies in the mental dispositions of the officers. They all know exactly what is to be done in every situation, but there are too many who do not react in the appropriate way when an unexpected combination of factors suddenly confronts them, such as the quick approach of a ship in the fog. He claimed that two different types ought to be excluded. There are ship officers who know the requirements excellently, but who are almost paralyzed when the dangerous conditions suddenly threaten. Their ability for action is inhibited. In one moment they want to act under the stimulus of one impression, but before the impulse is realized, some other perhaps rather indifferent impression forces itself on their minds and suggests the counteraction, and in this way they vacillate and remain inactive until it is too late to give the right order or to press the right button. The other type feels only the necessity for rapid action, and under the pressure of greatest haste, without clear thought, they jump to the first decision which rushes to their minds. Without carefully considering the conditions really given, they explode in an action which they would never have chosen in a state of quiet deliberation. They react on any accidental circumstance, just as at a fire men sometimes carry out and save the most useless parts of their belongings. Of course, beside these two types, there is the third type, the desirable one, the men who in the unexpected situation quickly review the totality of the factors in their relative importance and with almost instinctive certainty immediately come to the same decision to which they would have arrived after quiet thought. The director of the company insisted that it would be of highest importance for the ship service to discriminate these three types of human beings, and to make sure that there stand on the bridge of the ship only men who do not belong to those two dangerous classes. He turned to me with this request, as he had heard of the work toward economic psychology in the Harvard laboratory.

As the problem interested me, I carried on a long series of experiments in order to construct artificial conditions under which the mental process of decision in a complicated situation, especially the rapidity, correctness, and constancy of the decision, could be made measurable. I started from the conviction that this complex act of decision must stand in definite relation to a number of simpler mental functions. If, for instance, it stood in a clear definite relation to the process of association, or discrimination, or suggestibility, or perception, or memory, and so on, it would be rather easy to foresee the behavior of the individual in the act of decision, as every one of those other simple mental functions could be tested by routine methods of the psychological laboratory. This consideration led me to propose ramified investigations concerning the psychology of decision in its relation to the elementary mental processes. These studies by students of the laboratory are not yet completed. But I soon saw that they would be unfit for the solution of my practical problem, as we recognized that these relations between the complex act of decision and the elementary functions of the individual seem to have different form with different types of men.[12] If I was to approach the solution of the practical problem, accordingly, I had to reproduce in an experimental form the act of decision under complex conditions.

It seemed necessary to create a situation in which a number of quantitatively measurable factors were combined without any one of them forcing itself to consciousness as the most important. The subject to be experimented on then has to decide as quickly as possible which of the factors is the relatively strongest one. As usual, here, too, I began with rather complicated material and only slowly did I simplify the apparatus until it finally took an entirely inconspicuous form. But this is surely the most desirable outcome for testing methods which are to be applied to large numbers of persons. Complicated instruments, for the handling of which special training is needed, are never so useful for practical purposes as the simple schemes which can be easily applied. The form of which I finally made use is the following. I work with 24 cards of the size of playing-cards. On the upper half of every one of these cards we have 4 rows of 12 capital letters, namely, A, E, O, and U in irregular repetition. On 4 cards, one of these vowels appears 21 times and each of the three others 9 times; on 8 cards, one appears 18 times and every one of the three others 10 times; on 8 cards, one appears 15 times and each of the others 11 times; and finally, on 4 cards one vowel appears 16 times, each of the three others 8 times, and besides them 8 different consonants are mixed in. The person to be tested has to distribute these 24 cards as quickly as possible in 4 piles, in such a way that in the first pile are placed all cards in which the letter A is most frequent, in the second those in which the letter E predominates, and so on. As a matter of course the result must never be secured by counting the letters. Any attempt to act against this prescription and secretly to begin counting would moreover delay the decision so long that the final result would be an unsatisfactory achievement anyhow. It would accordingly bring no advantage to the candidate.

We measure with a stopwatch in fifths of a second the time for the whole process from the subject's looking at the first card to his laying down of the last card, and, secondly, we record the number and the character of his mistakes, if cards are put into wrong piles. I have made the experiment with very many persons, and results show that those various mental traits which have been observed in the practical ship service come clearly to light under the conditions of this experiment. Some of the persons lose their heads entirely, and for many of them it is a painful activity for which they require a long time. Even if the number of mistakes is not considerable, they themselves have the feeling that they are not coming to a satisfactory decision, because their attention is pulled hither and thither so that they feel an inner mental paralysis. Some chance letters stand out and appear to them to be predominant, but in the next moment the attention is captured by some other letters which bring the suggestion that they are in the majority and that they present the most important factor. The outcome is that inner state of indecision which can become so fatal in practical life. Other subjects distribute the cards in piles at a relatively high speed, and they do it with the subjective feeling that they have indeed recognized at the first glance the predominant group of letters. The exact measurement of the results, however, shows that they commit many errors which would have been improbable after quiet consideration. Any small group of letters which catches their eye makes on them, under the pressure of their haste, such a strong impression that all the other letters are inhibited for the moment and the wrong decision is quickly made. Finally, we find a group of persons who carry out the experiment rather quickly and at the same time with few mistakes. It is characteristic of them to pass through it with the feeling that it is an agreeable and stimulating mental activity. In all cases the subjects feel themselves under the unified impression which results from all those 48 letters of the card together; and this is the reason why the qualitative manifoldness of a practical life situation can be compared with these intermingled, quantitatively determined groups of letters.

If I consider the general results of these experiments only with reference to the time-measurement, I should say that a person who completes the distribution of the cards in less than 80 seconds is quick in his decisions; from 80 to 150, moderately quick; from 150 to 250, slow and deliberate and rather too deliberate for situations which demand quick action; over 250 seconds, he would belong among those wavering persons who hesitate too long in a life situation which demands decision. The time which is needed for the mere distribution of the cards themselves plays a very small role compared with the time of the whole process, and can be neglected. In order to determine this, I asked all the subjects before they made the real experiment to distribute 24 other cards in 4 piles, on each of which one of the four letters, A, E, O, and U was printed only once. Hence no comparison of various factors was involved in this form of distribution. The average time for this ordinary sorting was about 20 seconds. Only rather quick individuals carried it out in less than 18 and only very slow ones needed more than 25 seconds. This maximum variation of 10 seconds is evidently insignificant, as the variations in the experiment amount to more than 200 seconds. But it is very characteristic that the results of the two experiments do not move parallel. Some persons, who are able to sort the cards on which only one of the 4 letters is printed very quickly, are rather slow when they sort the cards with the 48 letters for which the essential factor is the act of comparison. In the first case the training in card-playing also seems to have a certain influence, but in the second case, our real experiment on decision, this influence does not seem to exist.

We have emphasized from the start that it is no less important to give consideration to the number of mistakes. A mere rapidity of distribution with many mistakes characterizes, as we saw, a mental system which is just as unfit for practical purposes as one which acts with too great slowness. But it would not have been sufficient simply to ask how many cards were put into wrong piles. The special arrangement of the cards with four different types of combinations was introduced for the purpose of discriminating among mistakes of unequal seriousness. When one letter appeared 21 times and the three others only 9 times, it was surely much easier to make the decision than when the predominant letter appeared only 15 times and the other three each 11 times. The easier the right decision, the graver the mistake. Of course the valuation of these mistakes must be rather arbitrary. We decided to value as 4 every mistake in these cards on which the predominant letter appears 21 times; as 3, a mistake in the 18 letter cards; as 2, a mistake in the 16 letter cards; and as 1, a mistake in the most difficult ones, the 15 letter cards. If the mistakes are calculated on this basis and are added together, a sum below 5 may indicate a very safe and perfectly reliable ability for decision; 5 to 12, satisfactory; 12 to 20, uncertain; and over 20, very poor. In order to take account of both factors, time and mistakes, we multiply the sum of the calculated mistakes by the number of seconds. If the product of these two figures is less than 400, it may be taken as a sign of perfect reliability in making very quick, correct decisions, in complex life situations; 400 to 1000 indicates the limits between which the ability for such decisions may be considered as normal and very satisfactory; 1000 to 2000, not good but still adequate; 2000 to 3000, unreliable, and over 3000, practically absent. It is clear that the real proof of the value of this method cannot be offered. This is just the reason why we selected this illustration as an example of the particular difficulty. Wrong decisions, that is, cases in which the man on the bridge waits too long before he makes his decision and thus causes a collision of ships by his delay, or in which he rushes blindly to a decision which he himself would have condemned after quiet deliberation, are rare. It would be impossible to group such men together for the purpose of the experiment and to compare their results with those of model captains, the more as experience has shown that an officer may have a stainless record for many years and yet may finally make a wrong decision which shows his faulty disposition. The test of the method must therefore be a somewhat indirect one. My aim was to compare the results of the experiments with the experiences of the various individuals which they themselves reported concerning their decisions in unexpected complicated situations, and moreover with the judgments of their friends whom I asked to describe what they would expect from the subjects under such conditions. The personal differences in these respects are extremely great, and are also evident in the midst of small groups of persons who may have great similarity in their education and training and in many other aspects of their lives.

Among the most advanced students of my research laboratory, for instance, all of whom have rather similar schooling and practically the same training in experimental work, the product of mistakes and seconds varied between 348 and 13,335. That smallest value occurred in a case in which the time was 116 seconds and the sum of the mistakes only 3, inasmuch as 3 cards of the most difficult group where the predominating letter occurred only 15 times were put in the wrong piles. The shortest time among my laboratory students was 58 seconds, but with this individual the sum of the mistakes, calculated on the basis of the valuation agreed upon, was 13. The largest figure mentioned resulted in a case in which the student needed 381 seconds and yet made mistakes the sum of which amounted to 35. It is characteristic that the person with the smallest product felt a distinct joy in the experiment, while the one with the largest passed through painful minutes which put him to real organic discomfort. If we arrange the men simply in the order of these products, of course we cannot recognize the various groups, as those who are quick but make mistakes and those who make few mistakes but act slowly may be represented by the same products. The coincidence of the results with the self-characterization is frequently quite surprising. Every one has at some time come into unexpected, suddenly arising situations and many have received in such moments a very vivid impression of their own mental reaction. They know quite well that they could not come to a decision quickly enough, or that they rushed hastily to a wrong decision, or that in just such instants a feeling of repose and security came over them and that with sure instinct they turned in the direction which they would have chosen after mature thought. The results of the experiments in sorting the cards confirmed this self-observation in such frequent cases that it may indeed be hoped that a more extended test of this method will prove its practical usefulness. It is clear that the field is a wide one, as these different types of mental dispositions must be of consequence not only in the ship service, but also to a certain degree in the railroad service and in many other industrial tasks.

We have emphasized from the start that as a matter of course such a tested function, while it is taken in its complex unity, is nevertheless not the only psychophysical disposition of significance. This is as true for the ship officer as it was for the motorman of the electric car. If we were to study all the mental dispositions necessary or desirable for the ship officer, we should find many other qualities which are accessible to the psychological investigation. The captain of the ship, for instance, is expected to recognize the direction of a vessel passing in the fog by the signals of the foghorn. But so far no one has given any attention to the psychological conditions of localization of sound, which were for a long while a much-studied problem of our psychological laboratories. We know how this localization is dependent upon the comparison of the two ears and what particular mistakes occur from the different sensibility of the two ears. Yet there are to-day men on the bridges of the ships who hear much better with one ear than with the other, but who still naively believe that, as they hear everything very distinctly with one ear, this normal ear is also sufficient for recognizing the direction of the sound. It is the same mistake which we frequently see among laborers whose vision has become defective in one of their eyes, or one of whose eyes is temporarily bandaged. They are convinced that the one good eye is sufficient for their industrial task, because they are able to recognize everything clearly and distinctly. They do not know that both the eyes together are necessary in order to produce that psychological combination by which the visual impression is projected into the right distance, and that in the factory they are always in danger of underestimating the distance of a wheel or some other part of the machine and of letting the hand slip between the wheels or knives. The results of experimental psychology will have to be introduced systematically into the study of the fitness of the personality from the lowest to the highest technical activity and from the simplest sensory function to the most complex mental achievement.



X

EXPERIMENTS IN THE INTEREST OF TELEPHONE SERVICE

Our plan was to illustrate the possibility of applying psychological experiments to the selection of fit applicants also in cases in which not one characteristic mental function stands out, but in which a large number of relatively independent mental activities are in play. I choose as an illustration of such cases the work of the employees at the telephone switchboard. A study of the psychological factors in this work is strongly suggested by the practical interests of the telephone companies, and may be looked on here exclusively from this point of view. The user of the telephone is little inclined to consider how many actions have to be carried out in the central office before the connection is made and finally broken again. From the moment when the speaker takes off the receiver to the cutting off of the connection, fourteen separate psychophysical processes are necessary in the typical case, and even then it is presupposed that the telephone girl understood the exchange and number correctly. It is a common experience of the companies that these demands cannot be satisfactorily fulfilled when a telephone girl has to handle more than 225 calls in an hour. The official statistics show that this figure is exceeded in not infrequent cases,[13] in extreme cases the number may even rise beyond 300. Moreover, in short periods of reinforced demands it may happen that for a few minutes even the rapidity of 10 calls in a minute is reached. Normally the burden is divided among the employees in such a way that about 150 calls fall to each one in an hour, and that this figure is passed considerably only in one morning and one evening hour. A skillful distribution of pauses and ample arrangements for rest, usually together with very excellent hygienic conditions, make it possible for the fit persons to be able to carry on this work without over-fatigue from 8 to 9 hours a day. On the other hand, it is only natural that such rapid and yet subtle activity under such high tension, where especially the quick localization of the correct hole is a difficult and yet indispensable part, can be carried out only by a relatively small number of human nervous systems. The inability to keep attention at such a high point for a long while, or to perform such rapid movements, or to retain the numbers correctly, does not lead to fatal accidents like those in the case of the unfit motormen, but it does lead to fatigue and finally to a nervous breakdown of the employees and to confusion in the service. The result is that the company is continually obliged to dismiss a considerable proportion of those who have entered the service and who have spent some months in going through the training school of the company. As one single company, the Bell Telephone Company, employs 16,000 operators, the problem is an expansive one, and it has bearing on the health of the employees as well as on the patience of the subscribers. But above all it refers to the economic interests of the company, inasmuch as every girl who satisfies the entrance conditions of hearing and sight, of school education and general personal appearance, receives some salary throughout the months of training in the telephone school. Since during the first half-year, in which the employee still works entirely under supervision, more than a third of those who had originally entered leave, partly on account of unfitness, and inability, partly on account of over-fatigue or similar reasons, the economic disadvantage to the company is evidently a very great one. The candidates are paid for months of mere training, and they themselves waste their energy and time with practice in a kind of labor which cannot be serviceable to them in any other economic activity. Under these circumstances it is not surprising that one city system approached me with the question whether it would not interest me from a scientific point of view to examine how far the mental fitness of the employees could be determined beforehand through experimental means.

After carefully observing the service in the central office for a while, I came to the conviction that it would not be appropriate here to reproduce the activity at the switchboard in the experiment, but that it would be more desirable to resolve that whole function into its elements and to undertake the experimental test of a whole series of elementary mental dispositions. Every one of these mental acts can then be examined according to well-known laboratory methods without giving to the experiments any direct relation to the characteristic telephone operation as such. I carried on the first series of experiments with about thirty young women who a short time before had entered into the telephone training school, where they are admitted only at the age between seventeen and twenty-three years. I examined them with reference to eight different psychophysical functions. In saying this, I abstract from all those measurements and tests which had somewhat anthropometric character, such as the measurement of the length of the fingers, the rapidity of breathing, the rapidity of pulse, the acuity of vision and of hearing, the distinctness of the pronunciation, and so on. A part of the psychological tests were carried on in individual examinations, but the greater part with the whole class together.

These common tests referred to memory, attention, intelligence, exactitude, and rapidity. I may characterize the experiments in a few words. The memory examination consisted of reading to the whole class at first two numbers of 4 digits, then two of 5 digits, then two of 6 digits, and so on up to figures of 12 digits, and demanding that they be written down as soon as a signal was given. The experiments on attention, which in this case of the telephone operators seemed to me especially significant, made use of a method the principle of which has frequently been applied in the experimental psychology of individual differences and which I adjusted to our special needs. The requirement is to cross out a particular letter in a connected text. Every one of the thirty women in the classroom received the same first page of a newspaper of that morning. I emphasize that it was a new paper, as the newness of the content was to secure the desired distraction of the attention. As soon as the signal was given, each one of the girls had to cross out with a pencil every "a" in the text for six minutes. After a certain time, a bell signal was given and each then had to begin a new column. In this way we could find out, first, how many letters were correctly crossed out in those six minutes, secondly, how many letters were overlooked, and, thirdly, how the recognition and the oversight were distributed in the various parts of the text. In every one of these three directions strong individual differences were indeed noticeable. Some persons crossed out many, but also overlooked many, others overlooked hardly any of the "a's," but proceeded very slowly so that the total number of the crossed-out letters was small. Moreover, it was found that some at first do poor work, but soon reach a point at which their attention remains on a high level; others begin with a relatively high achievement, but after a short time their attention flags, and the number of crossed-out letters becomes smaller or the number of unnoticed, overlooked letters increases. Fluctuations of attention, deficiencies, and strong points can be discovered in much detail.

The third test which was tried with the whole class referred to the intelligence of the individuals. Discussion of the question how to test intelligence in general would quickly lead us into as yet unsettled controversies. It is a chapter of the psychology of tests which, especially in the service of pedagogy but to a certain degree also in the service of medicine, has been more carefully elaborated than any other. Often it has been contested whether we have any right to speak of one general central intelligence factor, and whether this apparently unified activity ought not to be resolved into a series of mere elementary processes. The newer pedagogical investigations, however, speak in favor of the view that besides all special processes, or rather, above all of them, an ability must be recognized which cannot be divided any further, and by which the individual adjusts his knowledge, his experiences, and his dispositions to the changing purposes of life. The grading of the pupils in a class usually expresses this differentiation of the intelligence; and while the differences of industry or of mere memory and similar secondary features may sometimes interfere, it remains after all not difficult for an observant teacher to grade the pupils of his class, whom he knows well, according to their general intelligence. The psychological experiments carried on in the schoolroom have demonstrated that this ability can be tested by the measurement of some very simple mental activities. The best method would be the one which would allow the experimenter, on the basis of a single experiment, to grade the individuals in the same order in which they appear in the record of the teacher. Among the various proposed schemes for this purpose the figures suggest that the most reliable one is the following method, the results of which show the highest agreement between the rank order based on the experiments and the rank order of the teachers.[14] The experiment consists in reading to the pupils a long series of pairs of words of which the two members of the pair always logically belong together. Later, one word of each pair will be read to them and they have to write down the word which belonged with it in the pair. This is not a simple experiment on memory. The tests have shown that if instead of logically connected words simply disconnected chance words are offered and reproduced, no one can keep such a long series of pairs in mind, while with the words which have related meaning, the most intelligent pupils can master the whole series. The very favorable results which this method had yielded in the classroom made me decide to try it in this case too. I chose for an experiment 24 pairs of words from the sphere of experience of the girls to be tested. Two further class experiments belonged rather to the periphery of psychology. The exactitude of space-perception was measured by demanding that each divide first the long and then the short edge of a folio sheet into two equal halves by a pencil mark. And finally, to measure the rapidity of movement, it was demanded that every one make with a pencil on the paper zigzag movements of a particular size during the ten seconds from one signal to another.

After these class experiments I turned to individual tests. First, every girl had to sort a pack of 48 cards into 4 piles as quickly as possible. The time was measured in fifths of a second. The following experiment which referred to the accuracy of movement impulses demanded that every one try to reach with the point of a pencil 3 different points on the table in the rhythm of metronome beats. On each of these three places a sheet of paper was fixed with a fine cross in the middle. The pencil should hit the crossing point, and the marks on the paper indicated how far the movement had fallen short of the goal. One of these movements demanded the full extension of the arm and the other two had to be made with half-bent arm. I introduced this last test because the hitting of the right holes in the switchboard of the telephone office is of great importance. The last individual experiment was an association test. I called six words like "book," "house," "rain," and had them speak the first word which came to their minds. The time was measured in fifths of a second only, as subtler experiments, for which hundredths of a second would have to be considered, were not needed.

In studying the results so far as the memory experiments were concerned, we found that it would be useless to consider the figures with more than 10 digits. We took the results only of those with 8,9, and 10 digits. There were 54 possibilities of mistakes. The smallest number of actual mistakes was 2, the largest, 29. In the experiment on attention made with the crossing-out of letters, we found that the smallest number of correctly marked letters was 107, the largest number in the six minutes, 272; the smallest number of overlooked letters was 2, the largest, 135; but this last case of abnormal carelessness stood quite isolated. On the whole, the number of overlooked letters fluctuated between 5 and 60. If both results, those of the crossed-out and those of the overlooked letters, are brought into relation, we find that the best results were a case of 236 letters marked, with only 2 overlooked, and one of 257 marked, with 4 overlooked. The very interesting details as to the various types of attention which we see in the distribution of mistakes over the six minutes were not taken into our final table. The word experiments by which we tested the intelligence showed that no one was able to reproduce more than 22 of the 24 words. The smallest number of words remembered was 7. The mistakes in the perception of distances fluctuated between 1 and 14 millimeters; the time for the sorting of the 48 cards, between, 35 and 58 seconds; the association-time for the 6 associated words taken together was between 9 and 21 seconds. The pointing experiments could not be made use of in this first series, as it was found that quite a number of participants were unable to perform the act with the rapidity demanded.

Several ways were open to make mathematical use of these results. I preferred the simplest way. I calculated the grade of the girls for each of these achievements. The same candidate who stood in the 7th place in the memory experiment was in the 15th place with reference to the number of letters marked, in the 3rd place with reference to the letters overlooked, in the 21st place with reference to the number of word pairs which she had grasped, in the 11th place with reference to the exactitude of space-perception, in the 16th place with reference to the association-time, and in the 6th place with reference to the time of sorting. As soon as we had all these independent grades, we calculated the average and in this way ultimately gained a common order of grading. It is evident that this kind of calculation contains accidental factors, especially as a consequence of the fact that we give equal value to every one of these results. It might be better, for instance, to attribute a higher value to the attention experiment or to the intelligence experiment. This could be done by multiplying the results of some of these grades by 2 or by 3, which would bring the high or low grade of a girl for a particular function to stronger influence in the final result. But in this first trial I contented myself with the simplest uniform scheme in order to exclude all arbitrariness, and therefore considered the mere average of all the grades as the expression of the experimental result.

With this average rank list, we compared the practical results of the telephone company after three months had passed. These three months had been sufficient to secure at least a certain discrimination between the best, the average, and the unfit. The result of this comparison was on the whole satisfactory. First, the skeptical telephone company had mixed with the class a number of women who had been in the service for a long while and had even been selected as teachers in the telephone school. I did not know, in figuring out the results, which of the participants in the experiments these particularly gifted outsiders were. If the psychological experiments had brought the result that these individuals who stood so high in the estimation of the telephone company ranked low in the laboratory experiment, it would have reflected strongly on the reliability of the laboratory method. The results showed, on the contrary, that these women who had proved most able in practical service stood at the top of our list. Correspondingly, those who stood the lowest in our psychological rank list had in the mean time been found unfit in practical service and had either left the company of their own accord or else had been eliminated. The agreement, to be sure, was not a perfect one. One of the list of women stood rather low in the psychological list, while the office reported that so far she had done fair work in the service, and two others to whom the psychological laboratory gave a good testimonial were considered by the telephone office as only fair.

But it is evident that certain disagreements would have occurred even with a more ideal method, as on the one side no final achievement in practical service can be given after only three months, and because on the other side a large number of secondary factors may enter which entirely overshadow the mere question of psychophysical fitness. Poor health, for instance, may hinder even the most fit individual from doing satisfactory work, and extreme industry and energetic will may for a while lead even the unfit to fair achievement, which, to be sure, is likely to be coupled with a dangerous exhaustion. The slight disagreements between the psychological results and the practical valuation, therefore, do not in the least speak against the significance of such a method. On the other hand, I emphasize that this first series meant only the beginning of the investigation, and it can hardly be expected that at such a first approach the best and most suitable methods would at once be hit upon. A continuation of the work will surely lead to much better combinations of test experiments and to better adjusted schemes. But it would be most desirable that such studies be undertaken at various places according to various schemes in order to come nearer to the solution of a problem which is economically important to the whole public and to many thousands of employees. As soon as methods are really perfected it would seem not at all impossible that by a short experiment of a few minutes thousands of applicants might be saved long months of study and training which are completely wasted. For us here the detailed analysis of this particular case did not mean a suggestion to use to-day in the telephone offices of the country the special scheme which we applied, but it stood only as a clear, simple illustration of a method by which not the specific work itself is tested, but by which the industrial work of the individual is resolved into a long series of parallel functions each one of which is tested independently. The experimental aid which the laboratory has to supply in such cases is not a newly invented device, such as we needed in the case of the motormen, but simply the methods well known as so-called mental tests.

The experiments with such tests by which single mental functions are measured approximately in short quick examinations, has been much discussed in psychological circles. For a long while the thorough scholars remained very reluctant to accept such an apparently superficial scheme, when these tests were proposed especially for the pedagogical interests of the schoolroom. It was a time in which the scientific efforts were completely devoted to the general problems of the human mind and in which individual differences were very little considered. Moreover, the questions of applied psychology still seemed so far distant that the true scholar instinctively took his standards from the methods of purely theoretical research. Seen from such a point of view, it could not be denied that the tests were not sufficient to give us a complete scientific analysis of the personality in its subtler structure. The theorists knew too well that if the reactions, or associations, or memories, or tendencies of attention, or emotions of a subject were measured really with that scientific thoroughness which is the ideal of research, long months of experiments would be needed, and little could be hoped for from tests to be performed in half an hour. But this somewhat haughty reserve which was quite justified twenty years ago has become obsolete and would be meaningless to-day. On the one side the methods themselves have been multiplied; for each mental act like memory, attention, and so on, dozens of well-studied tests are at our disposal, which are adjusted to the finest ramifications of the functions.[15] On the other side the interest in individual differences and in applied psychology has steadily grown, and through it an understanding for the real meaning of the tests has been gained. Their value, indeed, lies exclusively in their relation to the practical problems. Where theoretical questions are to be answered and scientific studies concerning the laws and variations of the mind are to be undertaken, the long series of laboratory experiments carried on with patience and devotion are indispensable and can never be replaced by the short-cut methods of the tests. But where practical tasks of pedagogy or jurisprudence or medicine, or especially of commerce and industry, are before us, the method of tests ought to be sovereign. It can be adapted to the special situations and can succeed perfectly, if the task is to discover the outlines of the mental individuality for particular practical work.

The only real difficulty of the method lies in the ease with which it can be used. A device which presupposes complicated instruments deters the layman and will be used only by those who are well trained. Moreover, the amateur would not think of constructing and adapting such apparatus himself. But when nothing is necessary but to use words or numbers or syllables or pictures, or, as in those experiments which we just described, newspapers and so on, any one feels justified in applying the scheme or in replacing it by a new apparently better one according to his caprice. The manifoldness of the proposed tests for special functions, is therefore enormous to-day. What is needed now is surely much more that order be brought into this chaos of propositions, and that definite norms and standards be secured for certain chief examinations, than that the number of variations simply be increased.

The chief danger, moreover, lies in the fact that those who are not accustomed to psychological laboratory research are easily misled. They fancy that such an experiment can be carried out in a mere mechanical way without careful study of all the conditions and accompanying circumstances. Thereby a certain crudeness of procedure may enter which is not at all suggested by the test method itself. The psychological layman too seldom recognizes how many other psychical functions may play a role in the result of the experiment beside the one which is interesting him at that moment. The well-schooled laboratory worker almost automatically gives consideration to all such secondary circumstances. While his experiments may refer to the process of memory, he will yet at the same time carefully consider the particular situation as to the emotional setting of the subject, as to his attention, as to his preceding experience, as to his intelligence, as to his physiological condition, and many other factors which may have indirect influence even on the simplest memory test. Hence the real performance of the experiments ought to be undertaken only by those who are thoroughly familiar and well trained in psychological research. And they alone, moreover, can decide what particular form such an experiment ought to take in a given practical situation. It must be left to them, for instance, to judge in which cases the mental function of economic importance ought to be tested after being resolved into its components and in which it ought to be examined in its characteristic unity.



XI

CONTRIBUTIONS FROM MEN OF AFFAIRS

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 cooeperation 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

INDIVIDUALS AND GROUPS

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.