e following is not an
exhaustive list but includes only the most important and conspicuous
tendencies or methods together with the dates on which they were most
apparent.

(a) May 17, choice of first box at left of group or near it, then the
next in order, and so on, until the second from the right was reached.
This method with irregularities and certain definite skipping was used
at various times, sometimes over periods of several days, during the
course of the work.

(b) June 3, preference for number 3 and number 4 developed immediately
after the orang utan's illness and when he was working rather
listlessly.

On June 9 and 10, the original tendency (a) reappeared and persisted for
a number of series.

(c) June 14, a tendency to choose the box at or near the right end of a
group, and then the one next to it. In connection with this tendency,
which of course required only two choices in any given trial, interest
in playing with the sawdust on the floor developed.

Again on June 21, the animal returned to the use of tendency (a).

(d) June 29, movement to box at right end of group, hesitation before
it, and turning through a complete circle so that the second box from
the right was faced. This, the correct box, was often promptly entered.
This method, if persisted in, would obviously have yielded solution of
the problem.

(e) July 5, approach to and pretense to enter the box next to the right
end (right one), and then choice of some other box. This _feint_ is
peculiarly interesting, and its origin and persistence are difficult to
account for.

(f) In connection with the tendency to pretend that he was going to
enter the second box from the right end, Julius developed also the
tendency to turn around in front of the box at the right end, starting
sometimes to back into it, and then to enter, instead, the box second
from the end.

(g) July, 6 and 7, a fairly definite tendency to take the one next in
order or, instead, to go directly to the right box.

(h) July 10, direct first choices without approach to other boxes
appeared for the first time on this date.

For this problem, it proved impossible to establish and maintain uniform
conditions of experimentation. Instead, because of the failure of the
animal to improve and the tendency to discouragement, both punishment
and reward had to be altered from time to time, and other and more
radical changes were occasionally made in the experimental procedure.
Belo