ELIMINATION OF ERRORS IN THE MAZE 



69 



progressive, i.e., ten per cent progressive versus ninety per cent 

 not progressive. 



If we now count the cases where IV and V are eliminated 

 before II and III but not in a 5-4-3-2 order, e.g., Rats 4 and 16, 

 we find them to be nine, or forty per cent of the group, which 

 is less than would be expected on a chance basis. 



If, however, instead of considering individual cases, we look 

 at the averages, we still find no uniform progression. But 

 here again IV and V are eliminated before II and III. 



1 case (**) uniformly progressive or 6%, 

 vs. 

 16 cases not uniformly progressive or 94%. 

 5 cases where IV and V were eliminated before II and III, or 29%. 



Group B— 17 Rats 



These animals began the problem when sixty-five days old. 



Of the seventeen, one rat showed uniformly progressive elim- 

 ination while sixteen did not, i.e., six per cent progressive and 

 ninety-four per cent not progressive. 



