WHITE RAT AND THE MULTIPLE CHOICE METHOD 245 



a correct first choice in any trial is 1-5 and the probable ratio 

 or correct to incorrect first choices on a given day's trials, apart 

 from experience, is 1 to 4. With C this was exactly the ratio for 

 the first day's trials. It was also the ratio for the last day's trials. 

 B started with a ratio of 1 to 5 which was reduced to 1 to 2.3 at the 

 end, but there was no constancy in the results and the reactions 

 were so manifestly random that further training seemed useless. 



Although the rats failed to solve the problem, certain impor- 

 tant reactive tendencies were noted. C began the problem 4 

 days after the check series on problem 1. The old habit which 

 was manifest at the outset disappeared gradually and was little 

 in evidence after 100 trials. The tendency to enter the same 

 (incorrect) door two or more times in succession also disappeared 

 at about the same period in the training. Between trials 100 

 and 500 there was frequently a tendency to make several random 

 choices and then work from right to left, entering consecutive 

 doors successively, (cf, trials 133, 184, 338, 444). After this 

 stage the tendency was not so manifest, for the first random 

 choice was nearer the left. This latter fact also heightened the 

 probability of a first correct random choice, which doubtless 

 accounts for the higher scores in many of the later series. After 

 trial 250 there began to appear a tendency to enter the left door 

 and then the second from the left. (cf. trials 251, 254, 256, 257). 

 This tendency was increasingly manifest throughout. In trials 

 721-730 and 771-780, 8 out of 10 trials showed this type of re- 

 action. The animal did show a definite tendency to turn to 

 the left on leaving the entrance box, and often appeared to go 

 directly to the door at the extreme left of those that were open. 

 Whether it was merely this habit that was operative and the 

 second choice naturally involved the neighboring door, or whether 

 the rat formed the habit of going into the end compartment and 

 then the second can not be definitely stated. 



B was set at problem 2 without prior training in problem 1. 

 Consequently there was no previous habit to break. B was like- 

 wise very active. At the outset the same door would be entered 

 repeatedly (cf. trial 3), but this was seldom the case after 150 

 trials. There soon appeared a tendency after an incorrect choice 

 to enter alternate doors going rightward or to enter consecutive 

 doors going leftward. Sometimes the one tendency was followed 

 by the other, (cf. trials 167, 268). After trial 270 there some- 



