94 ROBERT M. YERKES 



them together he made no effort to place one upon another. 

 Certain of his methods are shown in plate V, especially by- 

 figures 21, 23 and 24. 



This experiment was continued on April 2 under yet different 

 conditions, for this time only two boxes were placed in the 

 cage, the one of them the heavy, irregularty shaped box and 

 the other the smaller, lighter one originally used. On the end 

 of the heavier box had been nailed a two by two inch wooden 

 block in order to increase the difficulty in using this box alone. 

 As previously, Julius made varied attempts to obtain the banana, 

 but on the whole his interest and attention seemed somewhat 

 weaker than previously and there were indications of discourage- 

 ment because of repeated failures. 



He handled the boxes conspicuously well, and it seemed at 

 times that he would certainly succeed in placing the one upon 

 the other and in reaching the food. 



After one series of attempts from the sides of the cage and 

 from the large box, he deliberately turned away from the box 

 and neatly executed a somersault on the floor of the cage, as 

 much as to say, " I am disgusted with the whole situation." 

 Again, later on the same day, after falling from the top of the 

 larger box, which tilted over very easily, he rolled himself into 

 a ball, and childlike, played with his feet. An additional evi- 

 dence of his changed affective attitude toward his task, especially 

 in connection with definite failures, appeared in his rough hand- 

 ling and biting of the boxes. When most impatient, he worked 

 very roughly. 



Julius was allowed to work for the reward from thirty to 

 ninety minutes, or, as a rule, until he had become completely 

 discouraged on April 3, 5, 6, 7, 8, 9 and 13. His behavior was 

 interesting and significant, but nothing new appeared except 

 that his willingness to work gradually disappeared, and on 

 April 13, although previously hungry, he made only a single 

 attempt to obtain the banana and then paid no further atten- 

 tion to it. 



The prolonged and varied efforts to obtain the banana were 

 due in a measure at least to three accidental successes. Thus 

 on April 2, 3 and again on the 5th, by fortunate combinations 

 of circumstances, he succeeded in getting the banana, contrary 

 to the intention of the experimenter. 



