252 Studies in Animal Behavior 



eral times and Lizzie solved her problem each time 

 with little or no hesitation, as in the first trial. 



The problem was then made a little more difficult 

 by placing the apple still farther out on the board 

 so that she could not reach it even when she had 

 pushed the end of the board as far to one side as 

 the limits of her cage would permit. When she had 

 pulled the board in and to one side, finding that 

 the apple was still out of reach, she tried to seize 

 the board by the side and to pull it in sidewise. It 

 was too difficult for her to get a good hold of the 

 board in this way, and her attempts were not suc- 

 cessful. I then drove a nail near the middle of 

 the board. Getting the apple involved pulling the 

 board to the cage by the first nail, pushing it then 

 to one side so as to bring the second nail within 

 reach, seizing the board by the second nail and pull- 

 ing it sidewise toward the cage until the apple was 

 sufficiently near. At her first trial Lizzie pulled 

 the board in by the first nail, then pulled it sidewise, 

 and tried to seize the edge of the board. Appar- 

 ently by accident her hand struck the second nail, 

 which she seized at once, and by its means pulled 

 in the board and got the apple. In the second trial 

 Lizzie pulled the board in and to the left, then 

 reached immediately for the second nail and pulled 

 in the board toward her cage. In several subse- 

 quent trials she secured the apple in just the same 

 way. The problem was solved perfectly after the 

 first trial. 



