INDUSTRIAL PSYCHOLOGY. Industrial psychology may be defined as the study of the conduct of men and women in their capacity as wage earners. It aims at describing and explain ing all those activities by means of which a person adjusts himself to his economic environment ; hence it must take into account the fundamental elements of man's constitution, his innate tendencies and their expression in thought, feeling and action both on the conscious and unconscious level, as well as his acquired aptitudes. As yet, only a tentative beginning has been made, so that we are far from even an approximation to scientific generalisation.
The development of industrial psychology has been largely determined by its history. Prior to 1914, psychologists concerned themselves but little with industrial problems. A few writers occasionally saw a possible industrial application of some psycho logical generalisation; and in 1913 Munsterberg made a more ambitious attempt (Psychology and Industrial Efficiency). Indus trial development had been governed by the claims of machinery rather than of man. The enormous improvement in machinery during the r 9th century, the studies made in the natural sciences, the growing knowledge of the mechanism of the body, all tended to focus general interest on man's likeness to a machine. The phrase "the human machine," which is rightly applied to part of his structure, became synonymous with man himself rather by implication than by design. The outbreak of the World War, with its urgent demands for increased production in all departments of activity, brought home to society the futility of considering the worker merely as a machine.
Industrial operations, as usually conducted, had been implic itly based on a crude mathematics. If 6 units of work could be done in one hour, then 6 x 8 would be done in 8 hours, 6 X 12 in 12 hours. The physiological necessity for sleep prevented the com plete working out of this principle. Up to about 6 or 7 hours, according to the nature of the work, there seemed ,nothing ob viously wrong with the calculation; when however, the problem was one of 12 hours, the discrepancy between the facts and the calculation challenged investigation. Though it was not then recognised, that stage marked an epoch in the history both of psychology and of industry. The focus of interest was changed from the machine to the worker of the machine, and the assistance of psychology, hitherto looked upon as a somewhat recondite study, was invoked.
Since the War, researches along these lines have been pursued in such different occupations as : charging of blast furnaces, silk weaving, shell making, metal-polishing, tinplate manufacture and in the processes of collar machining, folding and shirt ironing in the laundry trade. The curves of the output of the average worker, when graphed, usually assume the same general shape, viz., a rise at the beginning of the spell, a period of relative stability, and a fall at the end. The interpretation of these empirical facts cannot yet be given. Slight variations occur according to the ar rangement of the hours of work, but the type remains characteris tic of many industrial processes. Muscio, experimenting on women medical students doing mental tests, obtained similar curves.
The observations of H. M. Vernon for the Health of Munition Workers' Committee proved the advantage of breaking up work ing spells, and since then it has been verified in the boot industry, in metal-polishing, in celluloid-polishing, in shirt ironing, in sweet packing, in handkerchief-folding and in stamping lids. The intro duction of a rest about the middle of the spell of work improves the output as a rule by about 5%, and in some processes it affects advantageously the period preceding the rest. Not only is the work improved, but the regular rest is much appreciated by the worker. The probability is that the improvement is largely due to changes in feeling; most people can face with equanimity and possibly enthusiasm the prospect of two hours' work at the end of which will come a period of free time, but to face four or five hours of unbroken labour is depressing.
The subject of rest pauses has not yet been exhaustively studied, and particular cases need particular study; still the above state ments seem to be valid in general. Exactly when a rest pause should occur must depend on the nature of the work, while the amount of actual increase in output will vary with the relation of the human factor to the machine factor in the particular process.