-.6 E. L. THORNDIKE. 



Besides these simple acts, which any average chick will acci- 

 dentally hit upon and associate, there are, in the records of my 

 preliminary study of animal intelligence, a multitude of all sorts 

 of associations which some chicks have happened to form. 

 Chicks have escaped from confinement by stepping on a little 

 platform in the back of the box, by jumping up and pulHng a 

 string like that in D, by pecking at a door, by cHmbing up a 

 spiral staircase and out through a hole in the wall, by doing 

 this and then in addition walking across a ladder for a foot to 

 another wall from which they could jump down, etc., etc. Not 

 every chick will happen upon the right way in these cases, but 

 the chicks who did happen upon it all formed the associations 

 perfectly after enough trials. 



The behavior of the chicks shows the same general charac- 

 ter as that of the cat, conditioned, of course, by the different 

 nature of the instinctive impulses. Take a chick put in T (in- 

 clined plane) for an example. When taken from the food and 

 other chicks and dropped into the pen he shows evident signs 

 of discomfort ; he runs back and forth, peeping loudly, trying 

 to squeeze through any openings there may be, jumping up to 

 get over the wall, and pecking at the bars or screen, if such 

 separate him from the other chicks. Finally, in his general run- 

 ning around he goes up the inclined plane a way. He may come 

 down again, or he may go on up far enough to see over the top of 

 the wall. If he does, he will probably go running up the rest of 

 the way and jump down. With further trials he gains more 

 and more of an impulse to walk up an inclined plane when he 

 sees it, while the vain running and pecking, etc., are stamped out 

 by the absence of any sequent pleasure. Finally, the chick 

 goes up the plane as soon as put in. In scientific terms this his- 

 tory means that the chick, when confronted by loneliness and 

 confining walls, responds by those acts which in similar condi- 

 tions in nature would be likely to free him. Some one of these 

 acts leads him to the successful act, and the resulting pleasure 

 stamps it in. Absence of pleasure stamps all others out. The 

 case is just the same as with dogs and cats. The time-curves 

 are shown in Fig. i6. 



Coming now to the question of differences in intelligence- 



