82 ROBERT M. YERKES 



right choices per series increased from to 8. But, as the obser- 

 vations were continued from day to day, it became more and 

 more evident that the animal was merely passing from tendency 

 to tendency — method to method — mixing tendencies, and occa- 

 sionally developing new ones, without approach to the solution 

 of the problem. This fact would have led me to discontinue 

 the work much earlier than I actually did had it not been for 

 the peculiarity of the results obtained with problem 1. It 

 seemed not improbable that at any time Julius might succeed 

 in perfectly solving this problem over night precisely as he had 

 solved the first problem. 



A curiously interesting bit of behavior appeared for the first 

 time on June 29. Julius had gone to the first box at the right 

 end of the group, and instead of entering, he had wheeled around 

 toward his right, and turning a complete circle, faced the right 

 box, which he promptly entered. Subsequently, the tendency 

 developed and the method was used with increasing frequency. 

 On June 30, it appeared in the first series, four times, in the 

 second series, six times; on July 1, in the first series, three times, 

 and in the second series, four times; on July 2, in the first series, 

 five times, and in the second series, nine times. It was indeed 

 only by accident that the animal failed to fulfill the technical 

 requirement for perfect solution of the problem in this series. 

 Yet, had he done so, his subsequent trials would doubtless have 

 revealed the lack of any other idea than that of turning com- 

 pletely around before entering a box. 



This odd bit of behavior proved peculiarly interesting and 

 significant in that the tendency to turn became dissociated from 

 the position (in front of the first box at the right end of the group) 

 in connection with which it originally developed. After a few 

 days, Julius would enter the reaction-chamber and instead of 

 proceeding directly to the right end of the group, would stop 

 suddenly wherever he happened to be, turn toward his right in 

 a complete circle, and hasten into the box nearest to him which, 

 as often as not, proved to be the wrong one. Thus the idea of 

 turning completely about, which had it continued its associa- 

 tion with the idea of facing the first box at the right, would have 

 yielded success, instead became useless because of its dissociation. 



That the orang utan is capable of using free ideas seems clear 

 enough in the light of this behavior. That he proved incapable 



