44 K. S. L ASHLEY AND L. E. WILEY 



trained on the most complex maze, thus including in the 

 records of this maze any greater difficulty which the operated 

 animals may have had in adapting to the general training 

 situation. 3) His mazes differed markedly in the relations 

 of the culs de sac to the true path and so presented qualita- 

 tively different situations. 4) His cases included a greater 

 proportion of animals with extensive lesions and a few cases 

 with lesions greater than our present maximum. 5) Our mazes 

 all present the same general plan of simple right-left alterna- 

 tion and so admit the possibility of learning by a simple 

 generalization. 



The first of these differences in the experimental situations 

 does not seem likely to have produced the differences in 

 results, unless we assume that operated animals differ in 

 capacity for transfer of training from normals. Such an 

 assumption has been made by Melton ('31) concerning re- 

 troactive inhibition, but the evidence available indicates that 

 perseveration and consequently interference of habits is most 

 likely in the operated animals, and this would have tended to 

 make the simplest of Lashley's mazes (second in the series) 

 relatively more difficult for the operated animals. 



The common plan of our mazes might permit of learning by 

 simple generalization. But to account for our results on this 

 basis, we should have to assume that the capacity to general- 

 ize is less affected by extensive lesions than the capacity to 

 form associations between unrelated elements — an assump- 

 tion not in accord with Maier's experimental results ('31, 

 '32). 



The available data are not adequate to decide among the 

 remaining three possibilities. A large part of the inferiority 

 of the operated animals on Lashley's most complex maze was 

 evidently due to the inclusion of cases with lesions greater 

 than 50 per cent. We have few comparable cases and it may 

 be that the disproportionate retardation holds only for the 

 most severely deteriorated animals. However, the influence 

 of qualitative differences in the tasks cannot be disregarded. 



