230 



E. C. MACDOWELL AND E. M. VICARI 



1820 _ 



1540 _ 



EXCLUDING FAILURE RATS 



NCLUDING FAILURE RATS 



CONTROLS 



EXCLUDING FAFLURE RATS 



NCLUDING FAILURE RATS 



TIME PER DAY 



1.2 0.6 



Fig. 3 Learning curve based on time; averages per trial on each day of train- 

 ing and retention. The broken lines are tests; the solid lines, controls; the heavy 

 lines based on 'completes' and 'incompletes;' the light lines include 'failures' 

 as well. Males and females in all strains are put together in all cases. The 

 un its on the base lines are days : the first series of days are training; the second 

 series, retention; units on the vertical scale are seconds. 



