INTERFERENCE OF HABITS IN THE WHITE RAT 



53 



Table 2 presents the results for these controls. The four 

 days' records preceding control 1 were made at or above 87^% 

 correct. Each day's record with controls 1 and 3 alternated with 

 a day on the normal stimulus (handclaps) save when 80% was 

 made. In these cases the same control was used on the suc- 

 ceeding day. 



Ill 



Thirty-day Tests. — After control 3 had been given, each rat 

 of set A received the normal stimulus for four days or until the 

 standard 87 \°/ was reached. The animals were now started 

 upon the interference periods (B-E) as outlined above for 300 

 trials or 30 days. No rat learned his problem within this period. 

 Only one rat (No. 15) made 80% during any one-sixth (50 trials) 

 of the period. This rat made 82% during the third 50 and 84% 

 during the fourth 50 trials. (These are general averages for the 

 50 trials.) After this he broke down, so that on the final sixth 

 50% only was made. There is no available explanation for this. 

 Neither fear nor position habits intervened. It is one of those 

 anomalous cases that will occur. (It took this rat 180 trials 

 to relearn the normal habit. This, however, cannot be corre- 

 lated with the high percentage in the interference period because 

 long periods of relearning appeared in other rats where the high 

 percentages were absent.) Each of the succeeding 50 trials for 

 the rats in these sets averaged practically between 50 and 65%. 

 Table 3 contains a record of the number of correct reactions in 

 each 50 trials made by each rat during the 30 days. 



TABLE 3 



Trials Correct in Each 50 During the 30-day Test and the Relearning 



30-day training 



