EFFECT OF LENGTH OF BLIND ALLEYS ON MAZE LEARNING 11 



daily. Later four runs daily were tried, but the eagerness of 

 the animals seemed' in one or two cases to diminish in the last 

 •run. Three runs a day proved to be very satisfactory. It was 

 originally supposed that each rat could learn both one of the 

 B- and one of the A-mazes during the time available for the 

 experiment— July 18th to August 30th— but a difficulty arose, 

 which had been underestimated in the planning. When the 

 male rats had finished their more simple problems — the A- 

 ma7es — and were started on the B-maze problems, signs of 

 trailing the females appeared. To prevent this possibility the 

 male and the female groups of animals had been made to occupy 

 the same cages alternately in successive days. It was imprac- 

 ticable to wash the maze thoroughly before each experiment 

 for each group. The first day that the St and the RJ male 

 rats were run in the B-mazes, after the runs of the females, 

 there was no difficulty. On the second and the third day, 

 however, there seemed to be evidences of trailing and of excite- 

 ment, and some of the rats deposited urine drops in the maze 

 from the second to the fifth blind alleys. This seemed to 

 influence, as a guide, later members of the same groups (i. e., 

 also males), and to stimulate them to make similar deposits 

 along the trail. Thorough washing of the entire maze with 

 soap water and Creolin-Pearson, a disinfectant, did not change 

 the behavior materially. Consequently, after the third day the 

 practices of these males were discontinued for sixteen days, 

 until the females had completed their problem. This experience 

 with the males seemed in only one (questionable) case to 

 influence in the least the runs of the females whose habits had 

 been already reduced to the stage of proprioceptive control. 

 The mazes, moreover, had been carefully washed after the 

 second and the third day of the experience with the males 

 already described. 



The postponement of the experiment with the males in the 

 B-mazes made it necessary to run them by the intensive method 

 described in the schedule, if at all. It was found that if each 

 rat was given three runs and then put back into the cage without 

 feed it could again be run soon after with no loss of eagerness. 

 In fact, the method worked surprisingly well. The fact that 

 the records had nevertheless to be left incomplete on this maze 

 so far as these rats were concerned does not affect the data so 



