intermediate between the modern laboratory psychology and the problems
of economics: the psychological experiment is systematically to be
placed at the service of commerce and industry. So far we have only
scattered beginnings of the new doctrine, only tentative efforts and
disconnected attempts which have started, sometimes in economic, and
sometimes in psychological, quarters. The time when an exact
psychology of business life will be presented as a closed and
perfected system lies very far distant. But the earlier the attention
of wider circles is directed to its beginnings and to the importance
and bearings of its tasks, the quicker and the more sound will be the
development of this young science. What is most needed to-day at the
beginning of the new movement are clear, concrete illustrations which
demonstrate the possibilities of the new method. In the following
pages, accordingly, it will be my aim to analyze the results of
experiments which have actually been carried out, experiments
belonging to many different spheres of economic life. But these
detached experiments ought always at least to point to a connected
whole; the single experiments will, therefore, always need a general
discussion of the principles as a background. In the interest of such
a wider perspective we may at first enter into some preparatory
questions of theory. They may serve as an introduction which is to
lead us to the actual economic life and the present achievements of
experimental psychology.

It is well known that the modern psychologists only slowly and very
reluctantly approached the apparently natural task of rendering useful
service to practical life. As long as the study of the mind was
entirely dependent upon philosophical or theological speculation, no
help could be expected from such endeavors to assist in the daily
walks of life. But half a century has passed since the study of