APPETITES AND AVERSIONS AS CONSTITUENTS 



OF INSTINCTS. 



WALLACE CRAIG, 

 UNIVERSITY OF MAINE. 



GENERAL ACCOUNT OF APPETITE AND AVERSION. 



The overt behavior of adult animals occurs largely in rather 

 definite chains and cycles, and it has been held that these are 

 merely chain reflexes. Many years of study of the behavior of 

 animals studies especially of the blond ring-dove (Turtiir 

 risorius) and other pigeons have convinced me that instinctive 

 behavior does not consist of mere chain reflexes ; it involves other 

 factors which it is the purpose of this article to describe. I do 

 not deny that innate chain reflexes constitute a considerable 

 part of the instinctive equipment of doves. Indeed, I think it 

 probable that some of the dove's instincts include an element 

 which is even a tropism as described by Loeb. But with few 

 if any exceptions among the instincts of doves, this reflex action 

 constitutes only a part of each instinct in which it is present. 

 Each instinct involves an element of appetite, or aversion, or 

 both. 



An appetite (or appetence, if this term may be used with 

 purely behavioristic meaning), so far as externally observable, 

 is a state of agitation which continues so long as a certain stim- 

 ulus, which may be called the appeted stimulus, is absent. 

 When the appeted stimulus is at length received it stimulates a 

 consummatory reaction, after which the appetitive behavior 

 ceases and is succeeced by a state of relative rest. 



An aversion (example 7, p. 100) is a state of agitation which 

 continues so long as a certain stimulus, referred to as the dis- 

 turbing stimulus, is present; but which ceases, being replaced 

 by a state of relative rest, when that stimulus has ceased to act 

 on the sense-organs. 



The state of agitation, in either appetite or aversion, is exhib- 

 ited externally by increased muscular tension; by static and 



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