33^ Journal of Comparative Neurology and Psychology. 



7 was put in with him two more times, but still No. 9 refused to 

 make any further efforts to get out by digging. As he was cold 

 and inactive no further trials were made. 



Experiment IV. Pushing Open Door in "Top of Box. 



Method. — The apparatus consisted of a wire box 30 cm. long, 

 20 cm. wide and 12 cm. high. It was made of wire netting of half 

 inch mesh. In the top of the box near one corner a wire door was 

 made that opened upward. A rat could easily open this door by 

 pushing up against it with his nose or forepaws. A small glass 

 dish containing "Egg-O-See" was placed at one side of the closed 

 door. To get the food it was necessary for the rat to raise the door 

 and climb through. 



First, one rat was taught to raise the door and climb through 

 and then he was used to teach the others. The untrained rat 

 being put into the box with the trained one had an opportunity 

 to see him raise the door and climb out. If the untrained rat fol- 

 lowed the trained one out he was allowed to eat a little food and 

 then he was put back in the box by himself and kept there until he 

 got out or ceased to make any particular effort to get out. The 

 trained rat was then put in with hirh as before. 



The tables used in the following experiments are largely self- 

 explanatory. The first column represents the number of times 

 the trained rat got out when put in with the untrained one. The 

 second column represents the number of times the untrained rat 

 saw the trained one open the door. The third column shows the 

 number of times the untrained rat followed the trained one out. 

 And the fourth column represents the number of times the un- 

 trained rat got out when put back in the box by himself, after hav- 

 ing followed the trained one out. The last column is a record of 

 the time it took the untrained rat to get out when put in the box 

 by himself. If he did not get out by his own efforts no time 

 record was made. 



No. 2 IMITATING NO. i. 



No. 2 was put in the cage by himself for ten minutes. He tried 

 very hard to get out but did not succeed. 



