XV

THE ECONOMY OF MOVEMENT

The study of the technical aspect of labor can nowhere be separated by a sharp demarcation line from the study of the labor itself as a function of the individual organism.  Many problems, indeed, extend in both directions.  The student of industrial efficiency is, for instance, constantly led to the question of fatigue.  He may consider this fatigue as a function of brain and muscle activity and discuss it with reference to the psychophysical effort, but he is equally interested in the question of how far the apparatus or the machine or the accessory conditions of the work might be changed in order to avoid fatigue.  The accidents of the electric street railways were regarded as partly related to fatigue.  The problem was accordingly how to shorten the working time of the motormen in the interest of the public, but it was soon recognized that the difficulty might also be approached from the mere technical side.  Some companies introduced seats which the motormen can use whenever they feel fatigue coming and excellent results have followed this innovation.  In our last discussions the technical apparatus stood in the foreground.  We may now consider as our real topic the psychophysical activity.

Here, too, the leaders of scientific management have secured some signal successes.  Their chief effort in this field was directed toward the greatest possible achievement by eliminating all superfluous movements and by training in those movement combinations which were recognized as the most serviceable ones.  We may return to the case of the masons in order to clear up the principle.  When Gilbreth began to reform the labor of the mason after scientific principles, he gave his chief interest to the men’s motions.  Every muscle contraction which was needed to move the brick from the pile in the yard to the final position in the wall was measured with reference to space-and time-relations and the necessary effort.  From here he turned to the application of well-known psychophysical principles.  A movement is less fatiguing and therefore economically most profitable if it occurs in a direction in which the greatest possible use of gravitation can be made If both hands have to act at the same time, the labor can be carried out most quickly and with the smallest effort if corresponding muscle groups are at work and this means if symmetrical movements are performed.  If unequal movements have to be made simultaneously, the effort will become smaller if they are psychically bound together by a common unified impulse.  The distance which has to be overcome by hands, arms, or feet must be brought to a minimum for each partial movement.  Most important, however, is this rule.  If a definite combination of movements has been determined as economically most suitable, this method must be applied without any exception from the beginning of the learning.