going so well that it seemed desirable to begin the regular experiment.

On the morning of April 19, Skirrl was introduced to the apparatus and
given his first series of ten trials on problem 1. This problem demanded
the selection of the first door at the left in any group of open doors.
The procedure was as previously described in that the experimenter
raised the entrance doors of a certain group of boxes, admitted the
animal to the reaction-chamber, punished incorrect choices by confining
the animal for thirty seconds, and rewarded correct choices by raising
the exit door and thus permitting escape and the obtaining of food. The
trials were given in rapid succession, and the total time required for
this first series of ten trials was thirty-five minutes. Skirrl worked
faithfully throughout this interval and exhibited no marked
discouragement. When confined in a box he showed uneasiness and
dissatisfaction by moving about constantly, shaking the doors, and
trying to raise them in order to escape.

For the series of settings used in connection with problem 1, the reader
is referred to page 18. In the first setting, the doors numbered 1, 2,
and 3, were opened. As it happened, the animal when admitted to the
reaction-chamber immediately chose box l. Having received the reward of
food, he was called back to D, and doors 8 and 9 having been raised in
preparation for the next trial, he was again admitted to the
reaction-chamber. This time he quickly chose box 9 and was confined
therein for thirty seconds. On being released, he chose after an
interval of four minutes, box 8, thus completing the trial.

As it is highly important, not only in connection with the present
description of behavior, but also for subsequent comparison of the
reactions of different types of organism in this experiment, to present