234 The Animal Mind 



banked around the lower end of the box, if the digging was 

 done in a particular place; the other, by tearing off strips 

 of paper which held shut a spring door. The result of the 

 earlier series of experiments with the first-mentioned box 

 was that after an hour and a half on the first day one rat 

 happened to dig in the right place and entered. The second 

 day this rat took only eight minutes, and the thirteenth day 

 only thirty seconds, to enter. With the second box there 

 was always a tendency to begin by digging, and even in the 

 thirteenth experiment, where the rat got in by biting off the 

 papers in fifteen seconds, she began by two strokes of dig- 

 ging. In a later test with this box the rat chanced to be ex- 

 tremely hungry, and dug violently for several seconds, indi- 

 cating a blunting of the discriminative powers by hunger, 

 analogous to that which we have found in very low animals. 

 Like Porter subsequently, Small found that "if a rat happens 

 to succeed by several methods, as, e.g., biting, clawing, butting, 

 there is a strongly marked tendency to select the most ex- 

 peditious and effective method. This apparent selection, 

 however, is rather a matter of inertia than of prevision." 

 The rats were later trained to discriminate between the two 

 boxes, being sometimes presented with one and sometimes 

 with the other. Such experiments, however, may properly 

 be classed under the head of another method which we shall 

 presently discuss. Great individual differences were found 

 an^ng the rats : two of the four tested never learned to get 

 into the boxes so long as they were with their more energetic 

 companions, but merely profited by the activity of the latter 

 (386). Watson's puzzle-box experiments on the white rat 

 were designed, like his labyrinth tests, to compare the powers 

 of the adult with those of the young. The results were 

 practically the same as those of the labyrinth tests, except 

 that in the box experiments, where mere activity counts for 



