INTERFERENCE OF HABITS IN THE WHITE RAT 59 



ically as indicated in figure 2. The three lines to the left are 

 based upon rats 26, 27 and 29. The three lines to the right 

 are based upon the 18 rats of the 30-day test. The first line in 

 each column represents the average number of trials in learn- 

 ing the original h. c. habit; the second line, the trials given 

 on habit B; and the third line, the re-learning time. The de- 

 tailed data have already been given in the tables. The rats 

 represented in the right hand column averaged about 5 months 

 old at the beginning of the relearning tests. This was approx- 

 imately 2 months younger than the other set of animals at the 

 corresponding point of their tests. Both sets were composed 



w m 



he - 



8 gfe& 300 



he m - 1™ tW 50 



Figure 2. — Effects on retention of learned vs. unlearned habits. 



of active animals, however, and in view of the marked difference 

 in results as compared with Hubbert's, 2 1 am inclined to discount 

 age as an important factor in determining the present data. 



A comparison between these data and the results' of the 90- 

 day test points the way toward interesting interpretations. The 

 90-day rats had lost all measurable traces of the original h. c. 

 habit whereas rats 26, 27 and 29 relearned within an average 

 of 260 trials or 26 days. These three rats had spent 85 days 

 on habit B. Unless these are accidental variations, then, it 

 would seem that the training on B favored the retention of 

 h. c. The rats seemed equal in physical fitness for the tests. 

 If we now consider the relations of the data given in figure 1, 

 it would seem that the loss in retention of the first habit is prob- 

 ably caused as much or more by the lapse of time than by the forma- 

 tion of the contradictory habit. It was found in the 30-day test 

 that training had no greater effect on retention than lack of 

 training. It is thus suggested, although not clearly proved by 

 our tests, that the disintegration of certain habits in the rat is due 

 to a temporal factor and not to habit interference. 



2 Hubbert, H. B. The effect of age on habit formation in the albino rat. Be- 

 havior Monographs, 2, no. 6, 1915. 



