INSTINCT. 



63 



from jumping directly down, as it would instinctively do, and forc- 

 ing it to jump to another box on one side of it and thence down. 

 In the experiments which I made, the chick was prevented by a 

 second screen from jumping directly from the second box also. That 

 is, if in the accompanying figure, A is a box 34 inches high, B a box 

 25 inches high, C a box 16 inches high, and D the pen with the food 

 and other chicks, the subject had to go A-B-C-D. The chick tried 

 at first to get through the screen, pecked at it and ran up and 

 down along it, looking at the chicks below and seeking for a hole to 

 get through. Finally it jumped to B and, after a similar process, to 

 C. After enough trials it forms the 

 habit and when put on A goes im- 

 mediately to B, then to C and down. 

 Now if, after 75 or 80 trials, you take 

 away the screens, giving the chick a 

 free chance to go to D from either 

 A or B, and then put it on A, the 

 following phenomenon appears. The 

 chick goes up to the edge, looks 



over, walks up and down it for a while, still looking down at the 

 chicks below, and then goes and jumps to B as habit has taught it 

 to do. The same actions take place on B. No matter how clearly 

 the chick sees the chance to jump to D, it does not do so. The im- 

 pulse has been truly inhibited. It is not the mere habit of going 

 the other way, but the impossibility of going that way. In one case 

 I observed a chick in which the instinct was all but, yet not quite, 

 inhibited. When tried without the screen, it went up to the edge to 

 look over nine times, and at last, after seven minutes, did jump 

 straight down. — Animal Intelligence, an Experimental Study, etc., 

 pp. 99-100. New York, 1898. 



It remains to consider the so-called "perversions" of in- 

 stinct, that is, the cases where an instinctive activity appears 

 in response to a situation which it does not fit, or does not 

 ordinarily go with. The cat that nurses rats or puppies, the 

 pigeon that capers before a bottle, are stock examples. Most 

 of such are due to the essential indefiniteness of the instincts 

 in question. The cat does not have an impulse to nurse a 

 particular, definite thing, to wit, a young kitten, and to abhor 

 all else as subjects for nursing, and if her own young are only- 

 taken away and other young nursing things happen to be 



