ittle
food was given. Thus, the eagerness of the monkey to locate the right
box was increased and, as a matter of observation, his deliberateness
and care in choice increased correspondingly. Sixty seconds punishment
was found satisfactory, and it was therefore continued throughout the
work on this problem.

It was evident, on June 9, from the behavior of the monkey as well as
from the score, that the perfect solution of the problem was near at
hand. This fact the experimenter recorded in his daily notes, and sure
enough, on the following day Sobke chose correctly throughout the series
of ten trials. The time for this series was only ten minutes. The
choices were made deliberately and readily.

An analysis of the data of table 5 reveals five methods or reactive
tendencies which appeared more or less definitely in the following
order: (a) Choice of first box at the left, because of experience in
problem 1. This tendency was very quickly suppressed by the requirements
in connection with problem 2. Indeed one of the most significant
differences which I have discovered between the behavior of the primates
and that of other mammals is the time required for the suppression of
such an acquired tendency. The monkey seems to learn almost immediately
that it is not worth while to persist in a tendency which although
previously profitable no longer yields satisfaction, whereas in the
crow, pig, rat, and ring dove, the unprofitable mode of response tends
to persist during a relatively large number of trials. (b) The tendency
to choose, first, a box near the left end of the group, to go from that
to the box at the extreme right end of the group, thence to the one next
in order, which was, of course, the right box. This tendency appears
fairly clearly from May 7th on. (c) The box at the extreme right was
first chosen and then the one next to it. For example, in setting 2, box
4 would be chosen first, then box 3. Or, if this did not occur, the
method previously described under (b) was likely to be employed, as for
example, in setting 8, where such choices as 7.6.5.1.8 appear. (d) In
certain series there appeared a marked preference for a particular box,
usually box 3 (see results for May 24). This was doubtless due in a
measure, if not wholly, to the fact that box 3 was the right box twice
in each series of ten settings. But it should be added that the same is
true of box 7, for which no preference was manifested at any time. (e)
Di