486 BRAIN MECHANISMS AND LEARNING 



learning had been reached and he had been overtrained 80 trials on this 

 response the mask was reversed and B(^w was taught a second discrimina- 

 tion, Il-ab, while using the right eye. After this second response had been 

 similarly established and overtrained 80 trials, the cat received further 

 blocks of overtraining using alternately the left and right eyes. In the 

 end Bgw experienced 400 overtraining trials through each eye, each on its 

 own respective discrimination. Final overtraining performance with 



Table I 



INTEROCULAR TRANSFER IN CATS WITH OPTIC CHIASMA SECTIONED 



discrimination Ill-ab was 40 correct in 40 and with discrimination Il-ab, 

 38 correct in 40. 



On tests of cross-availability of knowledge run through the 'untrained' 

 eyes B^iw chose the correct pattern 39 times out of 40 on transfer testing 

 with discrimination Ill-ab and 37 times out of 40 on testing with dis- 

 crimination Il-ab. The few errors made were scattered throughout the 

 test session and were not necessarily made during the first trials. 



Examination of Table I reveals that in all instances but three the per- 

 formance using the untrained eye compares favourably with that using 



