14 



K. S. LASHLEY AND L. E. WILEY 



ultimate achievement might give more valid results than the 

 mere averaging of the crude data. Uncertainty as to the 

 legitimacy of the available methods, however, together with 

 the enormous labor involved in such computations has led 

 us to employ the crude scores. 



Animals which failed to run 



A few of the operated cases failed to reach the food com- 

 partment after 12 to 18 hours in the maze and became inactive 

 in the maze situation. Since such records of failure cannot 

 be interpreted in terms of capacity to learn, these cases were 

 simply discarded. Such behavior appeared most frequently 



TABLE 2 



Comparison of the four groups of operated animals with respect to extent of 



lesion as a test of the selective effect of excluding records of 



animals which failed to get through the maze 



among animals with extensive lesions and more often in the 

 longer than in the shorter mazes, so that there was probably 

 some selection exerted in this way. Table 2 summarizes the 

 distribution of lesions in the four groups compared. The 

 average destruction in the groups is essentially the same, 

 the variation within the groups is not greatly different. The 

 upper range indicates possible selection only for maze IV. 

 It is doubtful, therefore, whether the failure of cases to get 

 through the maze has had any appreciable effect upon the 

 results. "We have attempted to control this possible selection 

 by computing constants for animals with smaller lesions only 

 and comparing these with similar constants for the entire 

 group. 



