Experimental Study of Associative Processes 31 
tion will also be called to the force required. In general, 
however, that was very slight (20 to 100 grams if applied 
directly). The various boxes will be designated by capital 
letters. 
A. A string attached to the bolt which held the door ran 
up over a pulley on the front edge of the box, and was tied 
to a wire loop (24 inches in diameter) hanging 6 inches 
above the floor in front center of box. Clawing or biting it, 
or rubbing against it even, if in a certain way, opened the 
door. We may call this box A ‘O at front.’ 
B. A string attached to the bolt ran up over a pulley on 
the front edge of the door, then across the box to another 
pulley screwed into the inside of the back of the box 1} 
inches below the top, and passing over it ended in a wire loop 
(3 inches in diameter) 6 inches above the floor in back center 
of box. Force applied to the loop or #o the string as it ran 
across the top of the box between two bars would open the 
door. We may call B ‘O at back.’ 
Bi. In Br the string ran outside the box, coming down 
through a hole at the back, and was therefore inaccessible 
and invisible from within. Only by pulling the loop could 
the door be opened. Bui may be called ‘O at back 2d.’ 
C. A door of the usual position and size (as in Fig. 1) was 
kept closed by a wooden button 34% inches long, % inch 
wide, $ inch thick. This turned on a nail driven into the 
box 4 inch above the middle of the top edge of the door. 
The door would fall inward as soon as the button was turned 
from its vertical to a horizontal position. A pull of 125 
grams would do this if applied sideways at the lowest point 
of the button 2} inches below its pivot. The cats usually 
clawed the button round by downward pressure on its top 
edge, which was 1} inches above the nail. Then, of course, 
more force was necessary. C may be called ‘Button.’ 
