Experimental Study of Associative Processes 33 



latch, moreover, would fall back into place again unless the 

 door were pushed out at least a little. The top of this box 

 was not of bars or screening, but solid. We may call G 

 1 Thumb latch.' 



H was, except for the opening where the door was situated, 

 a perfectly solid and dark box. In the front was cut an 

 opening about 9X7 inches. A wooden frame covered with 

 wire netting hung in front of this. It was fastened to the 

 box only by a screw through the middle of the frame's top 

 piece, and could therefore be pushed to either side so as to 

 permit escape from the box if it were prevented from swing- 

 ing back into place. 



I was a box 12 x 14 X 23. The door was 8 inches wide, 4 

 high, and hinged at the left side. It was held closed by a 

 wooden bar which moved easily on a pivot and which could 

 be pushed up by another bar which projected 5 inches into 

 the box. This second bar was pivoted so that downward 

 pressure on it pushed the first bar up and let the door swing 

 open. The second bar entered the box at a point 4 inches 

 above the floor and 2\ inches in from the right side of the 

 box. In its normal position its inner end was 5^ inches 

 above the floor. A depression of 2 inches at that end was 

 necessary to open the door. Of course, nearer the pivot a 

 shorter depression would do. The front of the box was 

 closed by bars, but the rest by solid boards. We may call I 

 'Lever.' 



J was the same as B except that the door was not opened 

 by a weight as soon as the bolt was pulled up. On the con- 

 trary, the door was held closed by a small piece of board 

 (4 x 3^ x M thick) placed against it outside. After 

 pulling the loop at the back the cat had to knock down 

 this support and push the door open. We may call J 

 ' Double.' 



