Animal Psychology, the Old and the New 31 



responding segment will respond adaptively to many 

 stimuli that are applied to them. Many of the more 

 complex activities of the animal may be explained 

 as chain reflexes in which one act affords the stimu- 

 lus to the performance of other acts. The be- 

 havior of the whole animal might be regarded as the 

 result of a sort of social cooperation of the activi- 

 ties of its various quasi-independent nervous ganglia. 

 One cannot say that the seat of instinct in such an 

 animal is in the brain or any other part of the nerv- 

 ous system. The instincts of the animal are the 

 outcome of its general organization; they are the 

 expression of the workings of the organic mechan- 

 ism. Experiments indicate that the same conclusion 

 applies to the instinctive behavior of vertebrates. 

 Whether or not we regard instinct with Herbert 

 Spencer, as "compound reflex action," we may be 

 justified in concluding that it is everywhere a function 

 of organization. 



With the same aim at analysis a large amount of 

 work in recent years has been devoted to the sub- 

 ject of tropisms. Loeb's celebrated theory of orien- 

 tation attempts to explain these directed movements 

 of animals in terms of reflex action; many instincts 

 of animals are apparently the outcome of these 

 tropic reactions; even in the higher animals it is 

 probable that certain tropic responses are still re- 

 tained. As the tropisms are discussed more fully 

 in a later chapter this brief indication of their im- 

 portance in the development of animal psychology 



