VISUAL PERCEPTION OF THE CHICK 91 



in each individual test after the third. The individual records 

 in detail cannot well be presented, but reference to them 

 convinces me that these changes in behavior are related to 

 the occurrence of the shock. The "shaking up" in each test 

 where wrong choices occur clearly affects subsequent behavior. 

 No extraordinary results for No. 24 appear in table 5 prior 

 to series 10 in which the number of stimuli approaches drops 

 off abruptly. In series 9 and 10, as presented in table 6, a 

 change appears with reference to first approaches to inside 

 corners. The single first inside approach of series 9 occurs in 

 test 9 following a shock for a wrong choice. My notes in this 

 connection read: 



No. 24 is becoming wary of shocks; has not reached stage, however, of No. 27. 

 , No. 24 is very sensitive; jumps and screams sUghtly at each punishment; continues 



into compartment with sudden haste and jumps when shocked No. 



24 is beginning to appreciate that shock 'means something;' No. 27, in addition, 

 seems to be coming to an understanding of what the shock means. 



In connection with test 10, in which an error also occurs, 

 the following observations are reported: 



Approached — compartment very cautiously; entered cautiously after inspect- 

 ing compartment from two points of view, — one near the partition, the other 

 near the right side of the experiment box; stopped on receiving very brief shock 

 (did not jump or scream) ; same touch of key was repeated (no jump or scream) ; 

 turned out from right side; moved deUberately but continuously in a semi-circle 

 and entered — compartment near partition; started toward left front corner 

 (inside), but stopped 6 or 8 cm. from the beginning of the electric wires and 

 retraced the distance entered; turned sharply around end of partition, entered 

 + compartment, and crossed diagonally to + exit. 



In series 10, No. 24 made two first approaches to the inside 

 corners. One of these responses occurs in test 3 following 

 a shock, the other in test 5 where the inside corner of the com- 

 partment was first approached but followed by a retreat, a — 

 choice, and a shock. During the latter half of series 10, It 

 was observed that the chick became "hasty" in making choices. 



Turning now to the tabulated records of No. 25, table 5 

 shows for series 8 a sudden drop in the number of stimulus 

 approaches. Here, it appears, is the point where the severity 

 of the shock succeeded in taking the chick's attention away 

 from the stimulus. The punishment, as that for No. 24 In 

 series 9, tears up a "set" by commanding attention that was 



