STUDIES OF CEEEBRAL FUNCTION IN LEARNING. VII 



25 



group B had recovered from shock and were giving clear evi- 

 dence of discrimination after fourteen days, the experiment 

 seems to prove that neither general shock nor temporary dias- 

 chisis is an important factor in determining the inferior re- 

 tention of the animals with more extensive lesions. 



3. If small lesions produced no effect, whereas extensive 

 lesions abolished the habit of brightness discrimination, a 

 spurious correlation might arise through the inclusion of 

 both types of cases. It is possible that function is determined 

 by the presence of a critical amount of tissue, somewhat as 

 the power of regeneration is limited in lower animals. To 



Text fig. 3 Composite diagram made by superimposing the figures of the lesions 

 in cases 103 to 112, group C, showing the total range of the lesions in these cases. 



test this, the cases in table 3 were divided into three groups 

 comprising the cases with the lesser (nos. 50 to 66), median 

 (nos. 67 to 82) and greater (nos. 83 to 98) lesions and the 

 correlations for extent of lesion with errors in relearning 

 were computed for each of these subgroups. The constants 

 obtained were the following : 



For the lower third, p = 0.28 ± 0.15 

 For the middle third, p = 0.59 ± 0.11 

 For the higher third, p = 0.59 ± 0.11 



The correlation was also computed for group C, giving the 

 constant p = 0.30 ± 0.19. 



