200 



THE LOWER PRIMATES 



dinated movements of the eye and the hand. In their method of learning, 

 associative processes are quicker in formation of associations and there is 

 a greater number of such associations as well as greater delicacy, complexity 



Courtesy, American Museum oj Natural History 



FIGS. 105 AND 106. HAND AND FOOT OF SPIDER MONKEY. 



Left. Palmar surface of hand showing well-developed palm, marked digitation with complete absence 



of tlie thumb. 

 Right. PLintar surface of the foot showing long sole, small heel, short opposable hallux and long toes. 



and permanency in their representation. Yet, in spite of this increase as 

 compared with lower mammals, these associations fail in their full signif- 

 icance as utilizable behavioral components, probably because they lack 

 close interassociation. Thorndyke feels that there is nothing surprising in 

 the comparative absence of free ideas in these monkeys. The only demon- 

 strable intellectual advance of the monkeys over the mammals in general is 

 the change from a few, narrowly confined, practical associations to a far 

 greater assortment of them. This fact mav turn out to be at the bottom of the 



