96 



K. S. LASHLEY AND S. I. FRANZ 



The animal was stuporous and did not react to the problem 

 situation. On the following day she was active and gave evi- 

 dence of hunger. She wag given five trials on this day and five 

 trials per day thereafter for 8 days. The average time per trial 

 for the first five -trials of the retention tests was: to plane, 81 

 seconds; to door, 42 seconds. In the tests on the first day she 

 used no uniform method of springing the plane; she once pulled 



28 trial* S0 



FIG. 8. RATE OF IMPROVEMENT IN TRAINING AND RETENTION TESTS. 

 AVERAGE TIME PER SUCCESSIVE FIVE TRIALS is PLOTTED 

 FOR EXPERIMENT 20 



THE 



Learning 



Retention 



it up from behind, once jumped up on it from in front of the 

 food box, once walked straight across it from the back of the 

 box, and twice walked out on it from the rear. After the fourth 

 trial she adopted this latter method and used it uniformly in suc- 

 ceeding trials, varying the method only rarely by pushing down 

 the plane with her fore feet. In the learning trials she had uni- 

 formly climbed up from the rear of the box and tripped the catch 

 by pushing the plane down with her fore feet. 



