Classical Texts in Psychology
Christopher D. Green
York University, Toronto, Ontario
(Return to index)
Psychology and Industrial Efficiency
Hugo Münsterberg (1913)
CHAPTER 17: ATTENTION AND FATIGUE
THE problem of monotony may lead us on to other conditions through which attention is hindered and the product of labor thereby decreased. The psychologist naturally first thinks of external distractions of attention. If he turns to practical studies of the actual economic life, he is often decidedly surprised to find how little regard is given to this psychophysical factor. In industrial establishments in which the smallest disturbance in the machine is at once remedied by a mechanic in order that the greatest possible economic effect may be secured, frequently nobody takes any interest in the most destructive disturbances which unnecessarily occur in the subtlest part of the factory mechanism, namely, the attention apparatus of the laborers. Such an interference with attention must, for instance, be recognized when the workingman, instead of devoting himself to one complex function, has to carry out secondary movements which appear to be quite easily performed and not to hinder him in his chief task. Often his own feeling may endorse this impression. Of course the individual [p. 207] differences in this direction are very great. The faculty of carrying on at the same time various independent functions is unequally distributed and the experiment can show this clearly. It is also well known from practical life that some men can easily go on dictating to a stenographer while they are affixing their signature to several hundred circular letters, or can continue their fluent lecture while they are performing experimental demonstrations. With others such a side activity continually interrupts the chief function. Then some succeed better than others in securing a certain automatism of the accessory function to such a point that its special acts do not come to consciousness at all. For example, I watched a laborer who was constantly engaged in a complicated technical performance, and he seemed to give to it his full attention. Nevertheless he succeeded in moving a lever on an automatic machine which stood near by whenever a certain wheel had made fifty revolutions. During all his work he kept counting the revolutions without being conscious of any idea of number. A system of motor reactions had become organized which remained below the threshold of consciousness and which produced only at the fiftieth recurrence the conscious psychical impulse to perform the lever movement. Yet whether the talent [p. 208] for such simultaneous mastery of independent functions be greater or smaller and the demand more or less complex, in every case the principal action must be hampered by the side issue. To be sure, it may sometimes be economically more profitable to allow the hindrance to the chief work in order to save the expense of an extra man to do the side work. In most cases, however, such a consideration is not involved; it is simply an ignoring of the psychological situation. As the accessory work seems easy, its hindering influence on other functions is practically overlooked. Psychological laboratory experiments have shown in many different directions that simultaneous independent activities always disturb and inhibit one another.
We must not forget that even the conversations of the laborers belong in this psychophysical class. Where a continuous strain of attention has produced a state of fatigue, a short conversation will bring a certain relief and relaxation, and the words which the speaker hears in reply will produce a general stimulation of psychical energy for the moment. Moreover, the mere existence of the social conversational intercourse will raise the general emotional mood, and this feeling of social pleasure may be the source from which may spring new psychophysical powers. Nevertheless the [p. 209] fundamental fact, after all, is that any talking during the labor, so far as it is not necessary for the work itself, surely involves a distraction of attention. Here, too, the individual is not conscious of the effect. He feels certain that he can perform his task just as well, and even the piece-worker, who is anxious to earn as much as possible, is convinced that he does not retard himself by conversation. But the experiments which have been carried on in establishments with scientific management speak decidedly against such a supposition. A tyrannical demand for silence would, of course, be felt as cruelty, and no suggestion of a jail-like discipline would be wise in the case of industrial labor, for evident psychological reasons. But various factories in rearranging their establishments according to the principles of scientific management have changed the positions of the workmen so that conversations become more difficult or impossible. The result reported seems to be everywhere a significant increase of production. The individual concentrates his mind on the task with an intensity which seems beyond his reach as long as the inner attitude is adjusted to social contact. The help which is rendered by the feeling of social coöperation, on the other hand, is not removed by the mere abstaining from speaking. Interesting psychopedagogical [p. 210] experiments have, indeed, demonstrated that working in a common room produces better results than isolated activity. This is not true of the most brilliant, somewhat nervous school children, who achieve in their own room at home more than in the classroom. But for the average, which almost alone is in question for life in the factory, the consciousness of common effort is a source of psychophysical reinforcement. This evidently remains effective when the workingmen can see one another, even if the arrangement of the seats precludes the possibility of chatting during the work.
However, by far the more important cause of distraction of attention lies in those disturbances which come from without. Here again the chief interest ought to be attached to those interferences which the workman himself no longer feels as such. In a great printing-shop a woman who was occupied with work which demanded her fullest attention was seated at her task in an aisle where trucking was done. Removing this operator to a quiet corner caused an increase of 25 per cent in her work. To be sure there are many such disturbances in factory life which can hardly be eliminated with the technical means of to-day. For instance, the noise of the machines, which in many factories makes it impossible to [p. 211] communicate except by shouting, must be classed among the real psychological interferences in spite of the fact that the laborers themselves usually feel convinced that they no longer notice it at all. Still more disturbing are strong rhythmical sounds, such as heavy hammer blows which dominate the continuous noises, as they force on every individual consciousness a psychophysical rhythm of reaction which may stand in strong contrast to that of a man's own work. From the incessant inner struggle of the two rhythms, the one suggested by the labor, the other by the external intrusion, quick exhaustion becomes unavoidable.
If it were our purpose to elaborate a real system of psychological economics, we should have to proceed here to a careful study of the influences of fatigue on the industrial achievement. We should have to discuss the various kinds of fatigue and exhaustion, the conditions of restoration, and the whole group of related problems of psychophysics. But this is the one held which has been thoroughly ploughed over by science and by practical life in the course of the last decades. No new suggestion and no new hint of the importance of the problem is needed here. Our short discussion was planned to be confined to those regions which have not been worked up in [p. 212] systematic investigations and for which new devices seemed desirable. Hence we do not reproduce here the rich material of facts which the physiologists and psychophysicists have brought together in the last half-century, the importance of which for industrial labor is perfectly evident. Moreover, the practical applications and the insight into the social needs have transformed the factories themselves into one big laboratory in which the problem of fatigue has been studied by practical experiments. The problem of the dependence of fatigue and output upon the length of the working day has been tested in numberless places with the methods of really exact research, as it was easy to find out how the achievement of the laborers became quantitatively and qualitatively changed by the shortening of the working hours.
When in one civilized country after another the exhaustingly long working days of the industrial wage-earner were shortened more and more, the theoretical discussions of the legislators and of the social reformers were soon supplemented by careful statistical inquiries in the factories. It was found that everywhere, even abstracting from all other cultural and social interests, a moderate shortening of the working day did not involve loss, but brought a direct gain. The German [p. 213] pioneer in the movement for the shortening of the workingman's day, Ernst Abbé, the head of one of the greatest German factories, wrote many years ago that the shortening from nine to eight hours, that is, a cutting-down of more than 10 per cent, did not involve a reduction of the day's product, but an increase, and that this increase did not result from any supplementary efforts by which the intensity of the work would be reinforced in an unhygienic way. This conviction of Abbé still seems to hold true after millions of experiments over the whole globe. But the problem of fatigue has forced itself on the consideration of the men of affairs from still another side. It has been well known for a long while how intimate the relations are between fatigue and industrial accidents. The statistics of the various countries and of the various industries do not harmonize exactly, but a close connection between the number of accidents and the hours of the day can be recognized everywhere. Usually the greatest number of injuries occurs between ten and eleven o'clock in the forenoon and between three and four o'clock in the afternoon. The different distribution of the working hours, and of the pauses for the meals, make the various statistical tables somewhat incomparable. But it can be traced everywhere that in the first working hours [p. 214] in which fatigue does not play any considerable rôle, the number of accidents is small, and that this number sinks again after the long pauses. It is true that the number also becomes somewhat smaller at the end of the forenoon and of the afternoon period, but this seems to have its cause in the fact that with growing fatigue and with the feeling that the end of the working period is near, the rhythm of the activity becomes much slower, and with such slower movements the danger of accidents is greatly reduced. In a similar way the factories have had to give the fullest attention to the fatigue problem in its relation to the distribution of pauses, and above all in its relation to the advisable speed of the machines, the limits of which are set by the fatigue of the workingmen, and still more of the working-women.
The legislatures, the labor unions, and the manufacturers have then had this problem of fatigue constantly before their eyes. On the other hand, the psychologists and physiologists have continuously studied the fatigue and restoration of the muscle system and of the central nervous system, and have analyzed the facts with the subtlest methods. Yet, in spite of this, it cannot be denied that a real mutual enrichment has so far hardly been in question. On the contrary, the whole situation has again demonstrated the old [p. 215] experience. The mere trying and trying again in practical life can never reach the maximum effects which may be secured by systematic, scientifically conducted efforts. On the other side the studies of the theoretical scholars can never yield the highest values for civilization if the problems which offer themselves in practical life are ignored. The theorists have to prepare the ground, and in this preparatory work they must, indeed, remain utterly regardless of any practical situations. But after that a second stage must be reached at which on the foundation of this neutral research special theoretical investigations are undertaken which originate from practical conditions. As long as industrial managers have no contact with the experiments of the laboratory and the experimentalists are shy of any contact with the industrial reality, humanity will pass through social suffering. The hope of mankind will be realized by the mutual fertilization of knowing and doing.
The practical efforts of the factories have, indeed, not yet reached the point at which the greatest possible achievement which can be reached without over-fatigue may be secured. We called the abbreviation of the working day an experimental scheme. The question of reducing the working hours is so simple that no further special [p. 216] experiments are needed. But when we come to the questions of the pauses at work, the speed of work and similar factors related to fatigue, the situation is by far more complicated, and the often capricious changes in the plant have very little in common with a systematic experiment. Some well-known studies of the efficiency engineers clearly demonstrate the possibility of such systematic efforts. The best-known case is probably Taylor's study of the pig-iron handlers of the Bethlehem Steel Company. He found that the gang of 75 men was loading on the average about 12½ tons per man per day. When he discussed with various managers the question of what output would be the possible maximum, they agreed that under premium work, piecework, or any of the ordinary plans for stimulating the men, an output of 18 to 25 tons would be the extreme possibility. Then he proceeded to a systematic study of the fatigue in its relation to the burden and of the best possible relation between working time and resting time. His first efforts to find formulas were unsuccessful, because he calculated only the actual mechanical energy exerted and found that some men were tired after exerting energy of 1/8 hp. while others seemed to be able to produce the energy of ½ hp. Without greater fatigue. But soon he discovered the mistake in his figures. [p. 217] He had considered only the actual movements, and had neglected the period in which the laborer was not moving and was not exerting energy, but in which a weight was pulling his arms and demanding a corresponding muscular effort. As soon as this muscular achievement was taken into account, too, he found that for each particular weight a definite relation exists between the time that a man is under a heavy load and the time of rest. For the usual loads of 90 pounds, he found that a first-class laborer must not work more than 43 per cent of the working day and must be entirely without load 57 per cent. If the load becomes lighter, the relation is changed. If the workman is handling a half pig weighing 46 pounds, he can be under load 58 per cent of the day and only has to rest during 42 per cent.
As soon as these figures were experimentally secured, Taylor selected fit men, and did not allow them to lift and to carry the loads as they pleased, but every movement was exactly prescribed by foremen who timed exactly the periods of work and rest. If he had simply promised his men a high premium in case they should carry more than the usual la tons a day, they would have burdened themselves as heavily as possible and would have carried the load as quickly as possible, thus completely exhausting themselves after three [p. 218] or four hours of labor. In spite of such senseless exaggeration of effort in the first hours, the total output for the day would have been relatively small. Now the foremen determined exactly when every individual should lift and move the load and when he should sit quietly. The result was that the men, without greater fatigue, were able to carry 47½ tons a day instead of the 12½ tons. Their wages were increased 60 per cent. Such a trivial illustration demonstrates very clearly the extreme difference between an increase of the economic achievement by scientific, experimental investigation and a mere enforcing of more work by artificially whipping-up the mind with promises of extraordinary wages. Yet even such rules as the scientific management engineers have formed, may be elaborated to more lasting prescriptions as soon as the purely psychological factors are brought more into the foreground and are approached with the careful analysis of the experimental psychologist.
Such a systematic psychological inquiry is the more important for questions of fatigue, as we know that the subjective feeling of displeasure in fatigue is no reliable measure for the objective fatigue, that is, for the real reduction of the ability for work. Daily experience teaches us how easily some people overstep the limits of normal [p. 219] fatigue, and in extreme cases even come to a nervous breakdown because nature did not protect them by the timely appearance of strong fatigue feelings. On the other hand, we find many men and still more women who feel tired even after a small exertion, because they did not learn early to inhibit the superficial feelings of fatigue, or because the sensations of fatigue have in fact a certain abnormal intensity in their case. The question how far the psychophysical apparatus has really been exhausted by a certain effort must be answered with the help of objective research and not on the basis of mere subjective feelings. But such objective measurements demand systematic experiments in the laboratory.
The experiments which really have been carried on in the laboratory as yet, as far as they were not merely physiological, have on the whole been confined to so-called mental labor, and were essentially devoted to problems of school instruction or medical diagnosis. We have no doubt excellent experiments which are devoted to the study of the individual differences of exhaustion, fatigue, exhaustibility, ability to recover the lost energy, ability to learn from practice, and so on, but they are still exclusively adjusted to the needs of the school-teacher and of the nerve specialist and would hardly be immediately useful to the [p. 220] manager of a factory. We shall need a long careful series of investigations in order to determine how far those manifold results from experiments with memory work, thought work, writing work, and so on can be applied to the work which the industrial laborer is expected to perform.