AM.MAI BEHAVIOR 4N5 



since in its repetition it may be modified by experience; this 

 would be impossible if consciousness were not present, — in 1 

 the ability to profit by experience may he taken as a criterion of 

 effective consciousness. Another aspect of instinctive behavior 

 tends to confirm the presence of consciousness. In man) 

 the external stimulus which may give rise to a certain instincl 

 act is very obscure or appears too insignificant to awaken a 

 response. There seems to be a stronger impulse to the 

 from within; thus the taking of food may be due more directly 

 to a need for nutriment fell within the body than to the sight oi 

 food ; and further, in many instinctive acts, the external stimulus 

 appears to serve merely to arouse the stronger impulse from 

 within which gives rise to the instinctive response. It has, in 

 fact, been pointed out that the presence of a "felt need" 

 within the body may afford a distinction between the instinctive 

 act and the reflex action. 



When we come to consider the origin of instinct we find two 

 theories in existence, each of which has numerous adherents. 

 According to one theory instincts are inherited habits ; accord- 

 ing to the other they have been evolved through the natural 

 selection of the fittest methods of automatic response, that is to 

 say, of reflex action; this second theory is probably the more 

 widely accepted. Thus we see that thinkers on this subject 

 ascribe to the evolution of organic behavior the same principles 

 as to the evolution of organic structure, with the result that the 

 same phenomena are accounted for in two quite different ways. 

 The first theory assumes that these instinctive acts have been 

 acquired by the individual through repeated experimentation, 

 observation, and reflection until they have become automatic, 

 that is to say, habitual, and then these acquired habits are 

 inherited by the offspring and appear in them as instincts, 

 which do not have to be learned, although, it is said, they may 

 be forgotten. Unfortunately there are no very reliable facts 

 in support of this theory of the transmissibility of acquired 

 knowledge from parent to offspring, unless we give to the term 

 i)isliuct a much broader significance than it usually receives in 

 scientific discussion. The second theory is the pure application 

 of natural selection through the survival of the fittest, and while 

 some scientists maintain that this principle is all-sufficient, the 



