into the miniature situation, and especially uneducated persons are often very 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 method, while it is not necessary that the apparatus be similar to the electric car or that the external activities in the experiment be identical with their performance in the service.  After several unsatisfactory efforts, in which I worked with too complicated instruments, I finally settled on the following arrangement of the experiment which seems to me to satisfy those two demands.

The street is represented by a card 9 half-inches broad and 26 half-inches long.  Two heavy lines half an inch apart go lengthwise through the centre of the card, and accordingly a space of 4 half-inches remains on either side.  The whole card is divided into small half-inch squares which we consider as the unit.  Thus there is in any cross-section 1 unit between the two central lines and 4 units on either side.  Lengthwise there are 26 units.  The 26 squares which lie between the two heavy central lines are marked with the printed letters of the alphabet from A to Z. These two heavy central lines are to