On May 11 regular experimentation was begun with problem 2. Naturally
the situation presented unusual difficulties to the monkey because of
his previously acquired habit, and on the first day it was possible to
give only five trials, in all except the first of which Skirrl had to be
aided by the experimenter to find the right box. He persistently, as
appears in the first line of records of table 2, entered the first box
at the left. The series was continued on May 13, but with very
unsatisfactory results, since he apparently had been greatly discouraged
by the unusual difficulties previously met. Only four trials could be
given, and in these the showing made was very poor. It is noteworthy,
however, that in trials 6, 7, and 8, May 13, there was no marked
tendency to choose the first box at the left. Thus quickly had the force
of the previous habit been broken.

For problem 2, the total number of open doors in the ten settings is
fifty, as appears from the data on page 18, and as ten of these fifty
open doors may be defined as right ones, the expected ratio of right to
wrong first choices in the absence of previous training is 1 to 4. The
actual ratio for the first series given in problem 2 is 1 to 8, while in
the second series it is 0 to 10.

On the morning of May 13, work was interrupted in the ninth trial by
what seemed at the moment a peculiarly unfortunate accident, but in the
light of later developments, an incident most fruitful of valuable
results.

Skirrl, in trial 9, directly entered box 1. Since this was not the right
box, he was punished by being confined in it for ten seconds. While in
the box he howled and when the entrance door was raised for him to