496 BRAIN MECHANISMS AND LEARNING 



Performances through untrained eyes were 2S correct in 40 on tests with 

 discrimination Ill-ba and 20 correct in 40 on tests with discrimination 

 V-ba. 



In both of these latter instances of transfer testing a strongly persevera- 

 tive mode of responding occurred in which the animal pushed always or 

 nearly always on the door of one side regardless of which pattern it 

 contained. Because such positional perseveration tends to cc^ntinue and to 

 obscure test results, KrDi was next tested through the untrained eyes on 

 both discriminations under conditions of 'polarity reversal' in which 



Table V 



PERFORMANCES THROUGH TRAINED AND UNTRAINED EYES IN CATS WITH POST-TRAINING SECTION 



or CCJRPUS CALLOSUM 



Cat 



Discrimiuatiou 



Eye tested 



Pre-operative 

 performance 

 {correct in .^o) 



Post-operative 



performance 



[correct in sets of 40) 



Krni 



Byr 

 Sll 



Bgw 



Ill-ba 

 V-ba 

 Ill-ba 

 Ill-ab 

 V-ba 

 Ill-ba 

 Il-ab 



Trained (L) 

 Untrained (R) 

 Trained (R) 

 Untrained (L) 

 Trained (R) 

 Untrained (L) 

 Trained (R) 

 Untrained (L) 

 Trained (L) 

 Untrained (R) 

 Trained (L) 

 Untrained (R) 

 Trained (R) 

 Untrained (L) 



40 



40 



40 

 38 

 39 

 34 

 40 

 39 

 40 

 39 

 38 

 37 



40 



36 



30 



Left-sided craniotomy in all cases. 



* Exhibited strong positional perseveration. 



f Number correct in 20 trials run with polarity reversal. 



reward-punishment values of the stimuli were reversed. Under these 

 circumstances the animal chose the previously rewarded correct pattern 

 20 times in 20 in both instances despite its new association with punish- 

 ment. This peculiar effect of polarity reversal on positional perseveration 

 has also been clearly observed and described in work with interocular 

 transfer in the pigeon (Levine, 1945). Subsequent to the polarity reversal 

 testing Knii performed discrimination V-ba well through the untrained 

 eye. 



Bgw was similarly taught and overtrained on discriminations Ill-ab and 

 Il-ab while using the left and right eyes respectively. Prior to corpus 



