40 BRAINS OF RATS AND MEN 



co-operate, the motor V and motor VII nerves are 

 activated, and the food is held and ultimately 

 swallowed. If it feels right but tastes vile the motor 

 V is inhibited, the mouth opens, the motor VII is 

 activated, and the food is ejected by the tongue. If 

 the feel and the taste are extremely noxious, the 

 nervous impulse also passes down to the spinal cord 

 and the fish swims away. 



This is not a hypothetical case; it is well authen- 

 ticated. Here we have a rather elaborate system of 

 correlations, but no special correlation center is 

 provided. The entire performance is conducted 

 through nervous connections running between the 

 primary centers themselves. What happens in each 

 case seems to be determined by the relative potencies 

 of the several members of the complex. 



This sort of mechanism is adequate for many of 

 the simpler correlations, but its range is hmited and 

 it is not well adapted for rapid modification of behav- 

 ior through experience. More complex adjustments, 

 especially those which are individually learned, are 

 more efficiently served by special correlation centers 

 which are not directly connected with any peripheral 

 sense organs or under dominant control of any one 

 sensory system but which have indirect connections 

 with several primary sensory centers. Such a correla- 

 tion center is not physiologically dominated by any 

 one sensory system; the pattern of its internal nerv- 

 ous connections is not a rigidly fixed fabric of well- 



