ERRORS PER TRIAL 



NUMBERS 

 OF RATS 



FREQUENCY DISTRI BUTIONS OF AVERAGES FOR EACH RAT 



TESTS CONTROLS 



TEST AVERAGES <7 CONTROL AVERAGES ^ 



FIRST HALF TRAINING 



SECOND HALF TRAINING 



OMITTING THE FIRST DAY 



ALL TRAINING 



J I ^ ■» 



I 2 3 4 5 6 7 



9 10 II 12 13 l4 



RETENTION 



TRAINING AND RETE'NTION 



5 6 7 8 



rJUMBERSOF ERRORS 



Fig. 14 Frequency distributions of the individual averages of the numbers 

 of errors per trial, in the six groupings of the trials. Broken lines show the tests; 

 solid lines, the controls. Units on the base line are numbers of errors; units on 

 the vertical scale are numbers of rats. 'Completes' and 'incompletes' have 

 been used, with the males and females in all strains together. 



271 



