unsuccessful in such efforts. This can be clearly seen from the
experiences before naval courts, where it is usual to demonstrate
collisions of ships by small ship models on the table in the
courtroom. Experience has frequently shown that helmsmen, who have
found their course a life long among real vessels in the harbor and on
the sea, become entirely confused when they are to demonstrate by the
models the relative positions of the ships. Even in the naval war
schools where the officers play at war with small model ships, a
certain inner readjustment is always necessary for them to bring the
miniature ships on the large table into the tactical game. On the
water, for instance, the navy officer sees the far-distant ships very
much smaller than those near by, while on the naval game table all the
ships look equally large. On the whole, I feel inclined to say from my
experience so far that experiments with small models of the actual
industrial mechanism are hardly appropriate for investigations in the
field of economic psychology. The essential point for the
psychological experiment is not the external similarity of the
apparatus, but exclusively the inner similarity of the mental
attitude. The more the external mechanism with which or on which the
action is carried out becomes schematized, the more the action itself
will appear in its true character.

In the method of my experiments with the motormen, accordingly, I had
to satisfy only two demands. The method of examination promised to be
valuable if, first, it showed good results with reliable motormen and
bad results with unreliable ones; and secondly, if it vividly aroused
in all the motormen the feeling that the mental function which they
were going through during the experiment had the greatest possible
similarity with their experience on the front platform of the
electric car. These are the true tests of a desirable experimental