272 The Animal Mind 



ness whatever. A dog shows depression during his master's 

 absence, but his state of mind may be merely vague discom- 

 fort at the lack of an accustomed set of stimuli, not an idea 

 of what he wants. A cat, indeed, once observed by the 

 writer, did behave as a human being would do to whom an 

 idea had occurred, when, on coming into the house for the 

 first time after she had moved her kittens from an upper 

 story to the ground floor, she started upstairs to the old nest, 

 stopped half way up, turned and ran down to the new one. 

 But errors of interpretation are possible at every turn of such 

 observations. An attempt was made by Thorndike to test 

 experimentally the presence of ideas in the minds of the cats 

 he was studying by the puzzle-box method. He sat near the 

 cage where the cats were kept, and having made sure that the 

 cats were looking at him, he would clap his hands and say, 

 " I must feed those cats." Aften ten seconds he would take 

 a piece of fish, go to the cage and hold it through the wire 

 netting; the cat, of course, would climb up and get the food. 

 After from thirty to sixty trials the cat learned to climb up 

 when it heard him clap his hands and speak, without waiting 

 for him to get the fish. But it is not certain that the hand- 

 clapping came thus to suggest to the cat an idea of the ex- 

 perimenter's taking the food and coming to the cage ; rather, 

 in the course of so many repetitions, the clapping of the hands 

 may have become a direct stimulus to the act of climbing up, 

 although Thorndike thinks that the ten seconds 7 interval ren- 

 dered this improbable (393). Cole, as we have seen, has 

 observed behavior in the raccoon that might well be regarded 

 as involving ideas (82). 



Despite the difficulty of proving that animals have memory 

 ideas, it is not likely that any such gulf separates the human 

 mind from that of the higher animals as would be involved 

 in the absence from the latter of all images of past experiences. 



