LOCALIZATION OF LEARNING PROCESS 205 



readily acquired when the cortex is intact than after 

 loss of the visual area, but under the conditions of the 

 experiments reported this is not the case. The expla- 

 nation of this remarkable fact is not brought out in 

 the experiments under consideration. In all of these 

 experiments rats with partial destruction of the cere- 

 bral cortex seem to acquire the simple trial-and-error 

 habits here under consideration not only as readily as 

 uninjured rats, but in every type of case with fewer 

 trials and fewer errors. Lashley has discussed this 

 question. As he says in one place (1920, p. 91), "The 

 experiment seems to prove too much!" He points out 

 that in some of the kinesthetic-motor tests the condi- 

 tions of the experiment are such as actually to favor 

 animals which are depressed or partially paralyzed as 

 a result of the operations. In the case of the bright- 

 ness-discrimination experiments this does not seem to 

 be true, and yet even here animals deprived of the 

 visual cortex may learn the habit in about half the 

 number of trials required by normal rats. The num- 

 ber of cases involved here is small and the difference 

 might disappear with larger numbers, yet the uniform 

 presence of this peculiar feature suggests interesting 

 problems which at present can be discussed only theo- 

 retically. 



The facts reported seem to be inconsistent with 

 the conception of the dynamogenic function of the 

 cortex as developed above. But this function is not 

 the sole factor operative in cortical activity, and it 



