96 The Dancing Mouse 



accord, as a result of its abundant random activity, pass 

 through / into B within a few seconds, it is directed to the 

 doorway and urged through. A choice is now demanded 

 of the animal; to return to the nest- box it must enter either 

 the white electric-box or the black one. Should it choose 

 the white box, it is permitted to return directly to A by way 

 of the doorway E, the alley, and the swinging door at O, and 

 it thus gets the satisfaction of unobstructed activity, freedom 

 to whirl, to feed, and to retreat for a time to the nest. Should 

 it choose to attempt to enter the black box, as it touches the 

 wires of the interrupted circuit it receives a shock as a result 

 of the closing of the key in the circuit by the experimenter, 

 and further, if it continues its forward course instead of 

 retreating from the "stinging" black box, its passage through 

 E is blocked by a barrier of glass temporarily placed there by 

 the experimenter, and the only way of escape to the nest- 

 box is an indirect route by way of B and the white box. 

 Ordinarily the shock was given only when the mouse entered 

 the wrong box, not when it retreated from it; it was never 

 given when the right box was chosen. The box to be chosen, 

 whether it was white, gray, or black, will be called the right 

 box. The electric shock served as a means of forcing the 

 animal to use its discriminating ability. But the question of 

 motives in the tests is not so simple as might appear from 

 this statement. 



The reader will wonder why the mouse should have any 

 tendency to enter B, and why after so doing, it should trouble 

 to go further, knowing, as it does from previous experiences, 

 that entering one of the electric-boxes may result in dis- 

 comfort. The fact is, a dancer has no very constant tendency 

 to go from A to B at the beginning of the tests, but after it 

 has become accustomed to the box and has learned what 

 the situation demands, it shows eagerness to make the trip 



