12 'Journal of Comparative Neurology and Psychology. 



TABLE IX. 



Date 



Dec. I 



Dec. T, 



Dec. 7 



Dec. 8 



Dec. lo 



Dec. II 



Dec. 15 



Dec. 17 



Dec. 22 



Jan- I 



Jan-2 



Ja"-3 



Jan- 4 



Jan. 5..: 



Total 



M,Z 



M,Y,Z 



so' 



30' 

 30' 



30' 

 45' 

 60' 

 (>d 

 60' 



50' 

 60' 



ihr. 



2^hr. 



ihr. 



hr. 



kittens struck it, but never twice in succession. In one week I 

 taught X to roll the ball into the hole from any part of the triangle. 



After X had rolled the ball into the hole two or three times in 

 succession in the presence of Yj she was taken out and Y was left 

 in the box alone for five minutes, then X was put in with him 

 again. This was continued until Y learned to roll the ball into 

 the hole. Y got no meat when X rolled the ball into the hole 

 unless he got to the door first (see Table X). 



During the first few trials Y merely looked on, but gradually 

 he reached a point where he occasionally struck at the ball when 

 X was rolling it. The next step was to strike at it when he was in 

 the box alone. When X got the ball almost to the hole Y gave 

 the closest attention, and when the ball went in he dashed to the 

 door and tried to get the meat first. Not infrequently when X 

 got the ball almost to the hole Y knocked it in. Soon after he 

 had reached this stage he rolled the ball into the hole when he was 

 in the box alone. 



In the case of Z the method was the same as that employed with 

 Y, except that Z was generally fed when X rolled the ball into the 

 hole. Only twice in the forty-one trials of Table XI did Z 

 touch the ball. As far as I could see the only thing Z learned was 

 to associate the opening of the door with the hole, but not with 

 the rolling of the ball. When in the box alone she devoted most of 

 her time to the hole. Y, on the contrary, first formed the associa- 

 tion between the rolling of the ball and the opening of the door. 



