STUDIES OF CEREBRAL FUNCTION. IX 



43 



Ratio, 



Maze I 

 1.00 



Maze II 

 2.97 



Maze III 

 4.59 



Maze IT 

 6.23 



With this correction the operated animals do somewhat worse 

 proportionately on the longer mazes than do normals, but the 

 differences are still too small to be regarded as significant. 



As a further test we have computed the ratios for errors 

 for groups taken by increments of 10 per cent lesion as given 

 in table 15. These ratios are given in table 24. The figures 

 are more variable, owing to the smaller number of cases, but 

 there is no indication that any extent of lesion produces dis- 

 proportionately poorer records in the more complex mazes. 



TABLE 24 



The ratio of errors made during training for mazes II, HI, and IV to maze I, 

 for animals classed according to extent of lesion 



As by other methods of treating the data, there is no evidence 

 of any influence of cerebral lesion upon the proportionate 

 difficulty of the different mazes. 



DISCUSSION 



Our primary object in these experiments was to test the 

 influence of various amounts of cerebral destruction upon the 

 capacity to form habits involving different numbers of similar 

 tasks. We have failed to confirm Lashley 's finding ( '29) that 

 increasing the number of culs de sac disproportionately in- 

 creases the difficulty of the mazes for animals with brain 

 lesions. His experiments differed from the present ones in 

 the following respects: 



1) All animals were trained in all mazes, thus permitting of 

 transfer or interference effects. 2) His animals were first 



