Commercial life as a whole finds its contact with psychology, of course, not only in the problem of how to secure the best mental effect.  Those other questions which we have discussed essentially with reference to factory life and industrial concerns, namely, how the best man and the best work are to be secured, recur in the circle of commercial endeavors.  It seems, indeed, most desirable to devise psychological tests by which the ability to be a successful salesman or saleswoman may be determined at an early stage.  The lamentable shifting of the employees in all commercial spheres, with its injurious social consequences, would then be unnecessary, and both employers and employees would profit.  Moreover, like the selection of the men, the means of securing the most satisfactory work from them, has also so far been left entirely to common sense.  Commercial work stands under an abundance of varying conditions, and each may have influences the isolated effects of which are not known, because they have not been studied in that systematic form which only the experiment can establish.  The popular literature on this whole group of subjects is extensive, and in its expansion corresponds to the widespread demand for real information and advice to the salesman.  But hardly any part of the literature in the borderland regions of economics is so disappointing in its vagueness, emptiness, and helplessness.  Experimental psychology has nothing with which to replace it to-day, but it can at least show the direction from which decisive help may be expected in future.

XXIV

THE FUTURE DEVELOPMENT OF ECONOMIC PSYCHOLOGY

Here we may stop.  From those elementary questions concerning the mental effects, the path would quickly lead to questions of gravest importance.  What is the mental effect which the economic labor produces in the laborer himself?  How do economic movements influence the mind of the community?  How far do non-economic factors produce effects on the psychical mechanism of the economic agents?  But it would be idle to claim to-day for exact psychology, with its methods of causal thought, regions in which so far popular psychology, with its methods of purposive thought, is still sovereign.  Our aim certainly was not to review the totality of possible problems related to economic efficiency, but merely to demonstrate the principles and the methods of experimental economic psychology by a few characteristic illustrations.  As all the examples which we selected were chosen only in order to make clear the characteristic point of view of psychotechnics, it is unimportant whether the particular results will stand the test of further experimental investigations, or will have to be modified by new researches.  What is needed to-day is not to distribute the results so far reached as if they were parts of a definite knowledge, but only to emphasize that the little which has been accomplished should encourage continuous effort.  To stimulate such further work is the only purpose of this sketch.