6 | 4 |14 |16 | 1: 1.14
11 | 1321-1330 | 7.8 | 3 | 6 | 5 | 6.7 | 3.2 | 4 | 4.6.7.8 | 2.3 | 5.7 | 4 | 6 | | |
" | 1331-1340 | 7.8 | 3 | 6 | 4.5 | 6.7 | 2 | 4 | 6.7.8 | 3 | 7 | 6 | 4 |10 |10 | 1: 1.00
12 | 1341-1350 | 9.8 | 3 | 6 | 5 | 6.7 | 2 | 4 | 6.7.8 | 3 | 6.7 | 6 | 4 | | |
" | 1351-1360 | 7.8 | 3 | 6 | 5 | 6.7 | 2 | 4 | 7.8 | 3 | 6.7 | 6 | 4 |12 | 8 | 1: 0.67
19 | 1361-1370 | 7.8 | 3 | 6 | 5 | 6.7 | 2 | 4 | 6.7.8 | 3 | 6.7 | 6 | 4 | | |
| 1371-1380 | 9.8 | 3 | 6 | 5 | 7 | 3.2 | 4 | 7.9.8 | 3 | 6.8.7 | 6 | 4 |12 | 8 | 1: 0.67
========+===========+==============+==============+==============+==============+==============+==============+==============+==============+==============+==============+===+===+===+===+========

[Footnote *: Aided by experimenter.]

After two hundred and fifty trials on problem 2 had been given Julius,
it seemed desirable to introduce a radical change in method in order to
stimulate him to maximal effort. It was therefore decided to force him
to make a round trip through the apparatus in connection with each
choice, and to let this forced labor serve, in the place of confinement,
as punishment for mistakes. This new method yielded peculiar and
characteristic results. They differ from those previously obtained
largely because of the orang utan's remarkably strong tendency to
reenter the box through which he had just passed. This occurred so
persistently, as may be seen in table 9 (June 17, second series, June
18, etc.), that a further modification of method was introduced in that
after the same wrong box had been entered five times in succession, the
experimenter on the next choice of the box confined the animal for a
stated interval, say sixty seconds, in it, and then allowed it to escape
by way of the exit door and choose repeatedly until it finally located
the right box