REFLEX AND CONDITIONED ACTION 55 



source of the sound. This, also, is an innate reflex. 

 There is no direct connection between the primary 

 auditory center and the salivatory nucleus, and sali- 



correlation center 



finalj:omrnon path 



Salivarij qlond 



maxillarii 

 anqlion 



vQtoPLj nucleus 



cochlcQ 

 primarij Quditorij center 



Fig. 5. — Simplified diagram of the conditioned reflex. Primary (un- 

 conditioned) taste-salivatory arc In heavy continuous lines. Primary 

 auditory-head-turning arc in thin continuous lines. Secondary loops to 

 correlation center In broken lines. 



vation does not naturally follow excitation of the 

 auditory organ by a sound. 



If a bell is rung every time the animal is fed, he 

 learns to associate the bell with food, and ultimately 

 he will salivate at sound of the bell alone, even though 



