RONALD E. MYERS 503 



Ill-b, the pattern regularly punished during training through the opposite 

 trained eye. Some cats chose this pattern 40 times in 40 trials despite its 

 association with punishment. Tested through one eye they chose the one 

 pattern; tested through the other eye they chose the second pattern. One 

 hemisphere thus did not seem to benefit from the experience of the other 

 under conditions of moderate conflict. Stated in other terms the inter- 

 hemisphcric communication process lacked the capacity of bringing about 

 a differentiation of the two conflicting responses within a hemisphere. 

 From the extreme degree o( perseveration observed on the test trials of 

 transfer it was concluded that the effects of direct sensory experience are a 

 great deal more forceful in learning than the effects of information trans- 

 mitted between the hemispheres through the corpus callosum. 



ACKNOWLEDGMENTS 



The investigations were carried out while the author was associated 

 with the laboratory of R. W. Sperry. Support was received in turn from 

 the Abbott Memorial Fund of The University of Chicago, Frank P. 

 Hixon Fund of the California Institute of Technology, United States 

 Public Health Service and National Science Foundation Grant #G-388o. 



GROUP DISCUSSION 



Chow. Can you teach a cat these two discrimination problems, through the 

 same eye; 



Myers. Yes, under certain circumstances cats can consistently be taught the 

 conflicting discriminations through one eye. However, under other circumstances 

 they seem never to differentiate between the two closely conflicting sets of patterns 

 and have to be retaught each response with each reversal of the stimulus pairs. 



RosvoLD. I should like I^r Mvers to mention some of his work on tactile dis- 

 crimination in relation to visual discrimination since it gives a clearer picture of 

 corpus callosum function. 



Myers. The question of whether corpus callosum functions in tactual as well as 

 visual transfer is of great interest. The contribution of Bykov mentioned in the 

 discussion of Dr Segundo's paper served as a first beautiful demonstration of the 

 central importance of corpus callosum in the bilateral dissemination of information 

 bearing on tactual learning. A second contribution in the area of touch was made 

 b}- Stamm and Sperry who showed that the relatively slight degree of transfer of 

 tactile discrimination learning that occurs from one paw to the other in the cat is 

 interfered with by prior section of the corpus callosum (Stamm and Sperry, 1957). 

 Dr Ebncr, in our laboratorv at Walter Reed, has found immediate high level 

 transfer of tactile discrimination learning between the hands in normal monkeys 

 and complete failure in corpus callosum-scctioned animals (Ebner and Myers, 

 i960). Similarly, a comparable interference with intermanual transfer of latch-box 



