MENTAL LIFE OF MONKEYS AND APES 



27 



Trials 



Figure 18. — Error curves of learning for the solution of problem 1 

 (first box at left end). 



of experimentation. It appears from an analysis of the behavior 

 of Skirrl in problem 1 that there developed a single definite and 

 persistent method, namely, that of going to one box in the group, 

 and in case it happened to be a wrong one, of choosing, on 

 emergence from it, the next toward the right end of the group, 

 and so on down the line. Having reached the extreme right 

 end, the tendency was to follow the side of the reaction-chamber 

 around to the opposite end and to enter the first box at the 

 left end of the group, which was, of course, the right one. 

 This method appears, with certain slight variations, in approxi- 

 mately ninety per cent of the trials which involved incorrect 

 choices. Thus, in the case of trials 121 to 130, of which eight 



