INSTINCT 137 



time to time, controversy has raged in psychology over 

 these two terms and over the appropriate methodology of 

 study; but in recent years, as some authorities have pointed 

 out, the conflict is resolved in a psychology that seeks to 

 understand behavior in terms of the inner feelings and 

 thoughts of an animal. The two may be studied at one and 

 the same time, provided the study is confined to animals at 

 the same evolutionary level. 



Instinct, as has already been noted, plays the major role 

 in animals other than mammals. The lower down on the 

 scale of life we go, the greater is the role of instinct; but 

 it must be repeated that at no time is instinct to be consid- 

 ered in absolute control. In the same sense as we ascend the 

 scale, intelligence becomes more and more important; but, 

 again, even in man, intelligence is not in complete command 

 of the situation. On the contrary, there are many drives in 

 man that, at least under the definition of instinct as impul- 

 sion, do not fall within any list of intelligent traits. William 

 McDougall enumerated as instinctive in man the following: 

 fright, escape, pugnacity, curiosity, repulsion, self-display, 

 submission, sex, acquisitiveness, parental love, gregarious- 

 ness, hunting, imitation, and play (by children). Psycho- 

 analysts have used the term "wish" somewhat in the sense 

 of "instinct"; and various classifications have been proposed 

 for their list: ego; sex and herd; attraction, repulsion, and 

 aggression; and so on. Psychologists are convinced that 

 emotion and instinct are closely tied together, but do not 

 agree on how. It is clear, however, that in all organisms, 

 whatever their level, there are always powerful impulsions 

 from within which urge the animal toward action— action 

 which may be guided by such measure of intelligence as 

 may be displayed. Obviously, here is material that can be 

 worked over by natural selection. 



In analyzing this complex of instinct and intelligence, 

 psychologists distinguish at least three main evolutionary 

 stages of animal behavior. The stages are connected by 



