Everything went smoothly until August 2, when my assistant, who had been left in charge of the experimental work for a week, attempted to increase the number of trials per day to two series.  Sobke apparently was not quite ready for this increase in the amount of his day’s labor and refused to work at the end of the first series.  In this series he did less well than on the previous day.  The following day, August 3, unfortunately and contrary to the wishes of the experimenter, the laboratory was painted and there was necessarily considerable disturbance because of the presence of the workmen, and in addition, the pervasive odor of fresh paint.  Sobke chose still less successfully on this date, and on August 4, he refused to work after the eighth trial.  It is true that during these bad days the total number of choices steadily diminished while the successes, also, diminished, or at best, failed to increase.  When on August 9, I returned to the laboratory to take charge, I found that Sobke was no longer trying to solve the problem as when I had gone away.  His attitude had changed in that he had become indifferent, careless, and obviously discouraged with his task.

TABLE 7

Results for Sobke, P. rhesus, in Problem 4

========+===========+==============+==============+====

==========+==============+==============+==============+==============+==============+==============+==============+===+===+===+===+========
|    No.    |     S.1      |     S.2      |     S.3      |     S.4      |     S.5      |     S.6      |     S.7      |     S.8      |     S.9      |     S.10     |   |   |   |   | Ratio
Date  |    of     |              |              |   1.2.3.4    |              |              |  1.2.3.4.5   |              |              |   3.4.5.6    |              | R | W | R | W |   of
|  trials   |    2.3.4     |  5.6.7.8.9   |    5.6.7     |    7.8.9     |  4.5.6.7.8   |   6.7.8.9    |    1.2.3     |  2.3.4.5.6   |    7.8.9     |     6.7.8    |   |   |   |   | R to W
--------+-----------+--------------+--------------+---------

-----+--------------+--------------+--------------+--------------+--------------+--------------+--------------+---+---+---+---+--------
|           |              |              |              |              |              |              |              |              |              |              |   |   |   |   |
July  |           |              | {5.9.5.5     | {1.7.1.3     | {9.7.9.7     |              | {1.9.3.1     |              | {6.3.2.6     |              |              |   |   |   |   |
20   |    1- 10  | 2.4.2.4.3    | {5.9.5.6     | {1.7.1.7     | {7.9.7.9     | {8.4.8.4     | {9.2.9.3     | 3.1.3.2      | {3.6.3.2     | {9.3.4.3     | {8.6.6.8.6   | 0 |10 | 0 |10 | 0:10.00
|           |              | {5.8.7*      | {1.7.4*      | {7.7.8       | {4.6         | {9.1.5*      |              | {6.3.4*      | {3.9.3.6     | {8.6.8.6.7   |   |   |   |   |