Modification by Experience 243 



through the proper movement greatly facilitated the learning 

 process. Further evidence of the presence of ideas in the 

 raccoon's mind will be considered later (82). Yerkes has 

 found that the dancing mouse is aided in learning by being 

 put through the act (469). Hobhouse thinks that his cats, 

 dogs, elephants, and monkeys showed that their actions were 

 guided by an idea of the result, instead of being merely ac- 

 quired reactions to stimuli, because they varied the means 

 to the end. "In opening the sideboard drawer, Jack 

 [a dog] not merely pulls, but learns for himself how to get 

 his head into the drawer without shutting it again, altering 

 the method when he once hurts himself, and finding another. 

 So again, I have seen him, when standing up to pull open the 

 door of his box by means of a wire, accidentally pushing it 

 with his paws again as he let go. At a second trial he was 

 careful to avoid this, dropping the wire and pushing his 

 nose in as soon as there was room. Similarly, I have seen 

 the elephant shift the box that she was opening when she 

 had found that in a certain position the door would slam to 

 again before she could get her trunk in." These bits of 

 behavior, in Hobhouse's opinion, indicate that the animals 

 have ideas of the changes they wish to bring about (177). 

 While it may be rash to assert of any particular higher 

 animal that its consciousness never 'contains ideas, yet the 

 slow acquisition observed in many of these experimental 

 tests certainly gives evidence of a process of learning whose 

 essence consists simply in the gradual dropping off of un- 

 necessary movements. Upon the nature of this process, 

 psychology can throw little light. Thorndike declares that 

 the successful movement is "stamped in" because pleasure 

 results from it, while the unsuccessful movements are 

 "stamped out" because no pleasure results. The terms 

 " stamping in " and " out " must refer to some effect upon 



