106 



CHARLES A. COBURN AND ROBERT M. YERKES 



TABLE 6— Continued 



Daily Series and Averages, with Ratios of Correct to Incorrect 



First Choices 



Problem 2 



The summary of choices given in table 5 is 'chiefly valuable 

 as a means of detecting reactive tendencies. But it also indicates 

 that neither crow succeeded in solving the problem. We had 

 supposed, from our previous experience, that within two or 

 three weeks the crows would be choosing the second compartment 

 at the left with ease, but as a matter of fact, with the appearance 

 and disappearance of the more or less unsatisfactory reactive 

 tendencies apparent in table 5, they continued their work over 

 a period of several weeks without mastering the situation. It 

 seemed utterly useless to continue the experiment with this 

 problem beyond the five hundredth trial. Had there been any 

 consistent improvement, even although extremely slow, we 

 should have felt justified in continuing the training. 



The presentation of results in table 6 is of interest primarily 

 because the reader can from it see the fluctuation in the measure 

 of success during the long continued period of training. We 

 have presented in this table for each bird the number of correct 

 and incorrect first choices by series of trials under each date. 

 Following the results appear the ratios of successes to failures 

 for each day. 



