choice of the
right box was made at all frequently. Previously, selection of it had
been made almost invariably after approach to other boxes. But in the
second series for July 10 there was an extraordinary improvement in
method. This developed in the presence of two visitors, and it is
therefore all the more surprising. The choices were made not only
directly, but with decision and evident certainty that was quite at
variance with the previous behavior of the animal.

All the while through variation of methods, I was seeking to discover
the best means of holding the orang utan to his maximum effort and care
in attempting to select the right box. One day it would seem as though
forcing him to make round trips with rewards only for correct first
choices proved most satisfactory, and the next it might seem equally
clear that punishment by confinement for thirty seconds or sixty
seconds, with reward for correct choice in every trial, yielded better
results. In the end I had to admit that no best method had been
demonstrated and that I had failed to develop conditions which served to
compel the animal's attention to the problem and to lead him to work
without discouragement. There were, it is true, days on which it seemed
practically certain that the problem would be solved, but as it turned
out, Julius never succeeded in choosing correctly--throughout a series
of ten trials.

As a last resort, in order to make perfectly sure that the orang utan
was doing his best, I decided to introduce corporal punishment in a mild
form. For this purpose, I placed my assistant in charge of the apparatus
and the series of trials, and stationed myself in one corner of the
reaction-chamber with a whip in my hand. Whenever Julius entered a wrong
box, I approached him with the whip and struck at him, being careful not
to injure him and rarely striking him at all, for the threat was more
effective than a blow. He was extremely afraid of the whip and would
begin to whine and attempt to get out of the way as soon as he saw it.

This method was introduced on August 10, but no improvement resulted,
and in the end there was no reason to consider it more satisfactory than
the other procedures. I am now wholly convinced that Julius did his best
to choose correctly in the majority of the numerous series which were
given him in connection with problem 2.

From trials 1001 to 1100, a radical departure from the previous methods
was introduced in that