110 CHARLES A. COBURN AND ROBERT M. YERKES 



coming out of the first compartment and turning sharply it 

 entered the one directly in front of it, but now it met, instead, 

 with punishment. Nevertheless, it persisted in reentering the 

 wrong compartment, and in trial two hundred and fifty-three it 

 was punished thirteen times for entering compartment 7. It 

 was then aided in finding the right compartment. In this 

 instance, even after the door of the wrong compartment which 

 had been so often reentered had been closed and the door of the 

 right compartment left open beside it, the bird stood for some 

 seconds before the wrong door, cawing and apparently eager 

 to enter. 



Naturally the tendency to turn to its right instead of to its 

 left greatly diminished the number of correct first choices by 

 number 3, and completely obliterated the old reactive tendency. 

 Shortly, the number of reentrances diminished to two or three, 

 and the bird began to enter the second compartment from the 

 left, even although it were not facing it after it turned about. 

 This peculiar behavior continued for only a short time, and was 

 followed by a tendency to enter first a compartment near the 

 right end of the series. On escaping from this, it would turn 

 to its right and enter the compartment directly in front of it. 

 Repetition of this performance of course soon brought the bird 

 to the right compartment. In trial after trial, number 3 would 

 enter the first compartment at the right and then work back, 

 compartment by compartment, until it reached the second from 

 the left. Examples of this behavior are trials two hundred and 

 eighty, two hundred and eighty-eight, three hundred and nine, 

 three hundred and twenty, and so on. 



After the thorough testing of the reactive tendency just 

 described, no additional habit became well established, but the 

 crow shifted from one method to another. The one most often 

 used was that of entering the third from the left, and on leaving 

 this, turning to the right and entering the compartment before 

 it, which was of course the right one. This method is exhibited 

 for setting No.. 2, 6-9, after the two hundred and eighty-fourth 

 trial; for setting No. 5, 1-6, after trial two hundred and seventy- 

 seven; for setting No. 6, 5-9, after trial three hundred and 

 eighteen; and for setting No. 10, 2-5, after trial two hundred 

 and ninety-two. For the other settings, it appeared less 

 frequently. 



