66 E. L. THORNDIKE. 



From these quotations it seems fairly sure that if we should 

 ask Mr. Morgan, who is our best comparative psychologist, 

 what took place in the mind of one of these cats of our experi- 

 ments during the performance of one of the ' tricks,' he would 

 reply : " The cat performs the act because of the association of 

 ideas. He is reminded by the sight of the box and loop of his 

 experience of pulling that loop and of eating fish outside. So 

 he goes and pulls it again." This view has stood unchallenged, 

 but its implication is false. It implies that an animal, whenever 

 it thinks of an act, can supply an impulse to do the act. It takes 

 for granted that the performance of a cat who gets out of a box 

 is mentally like that of a man who thinks of going down street 

 or of writing a letter and then does it. The mental process is 

 not alike in the two cases, for animals can not provide the im- 

 pulse to do whatever act they think of. No cat can form an 

 association leading to an act unless there is included in the asso- 

 ciation an impulse of its own which leads to the act. There is 

 no general storehouse from which the impulse may be supplied 

 after the association is formed. 



Before describing the experiments which justify these state- 

 ments, it will be worth while to recall the somewhat obvious 

 facts about the composition of one of these associations. There 

 might be in an association, such as is formed after experience 

 with one of our boxes, the following elements : 



1. Sense-impression of the interior of the box, etc. 



2. (a) Discomfort and (<5) desire to get out. 



3. Representation of oneself pulling the loop. 



4. Fiat comparable to the human " I'll do it." 



5. The impulse which actually does it. 



6. Sense-impression of oneself pulling the loop, seeing one's 

 paw in a certain place, feeling one's body in a certain way, etc. 



7. Sense impression of going outside. 



8. Sense-impression of eating, and the included pleasure. 

 Also between i and 4 we may have 9, representations of one's 



experience in going out, 10, of the taste of the food, etc. 



6, 7 and 8 come after the act and do not influence it, of 

 course, except in so far as they are the basis of the future 3's, 

 9's and lo's. About 2 we are not at present disputing. Our 



