The Role of Sex in the Evolution of Mind 243 



ingly. Often pursuit and capture or winning over 

 are the necessary preliminaries of mating. All this 

 puts a premium so to speak on the sharpening of 

 the senses, the development of strength and acute- 

 ness, and the evolution of higher psychical qualities. 

 Consider the mating activities of crustaceans, the 

 courtship of spiders, the breeding activities of fishes, 

 and still more the elaborate wooing of male birds, 

 and it will become manifest how greatly the insti- 

 tution of sex must have stimulated the evolution of 

 more complex modes of behavior. 



All the facts here cited are trite enough even to 

 the non-biological reader. But while it is sufficiently 

 evident that the differentiation of the sexes has pro- 

 moted the development of behavior in relation to 

 mating, it may be well to point to the enormous in- 

 direct consequence of this development in respect 

 to the evolution of mind in general. In the evolu- 

 tion of behavior one kind of instinct grows out of 

 another just as new organs are usually formed by 

 the elaboration of some pre-existing structure. A 

 general elaboration of instinctive reactions in re- 

 gard to any one sphere of activity affords a basis, 

 therefore, for the differentiation of more complex 

 or specialized behavior in respect to other activi- 

 ties. The primary function of the voice, as has al- 

 ready been pointed out, was to serve as a sex call. 

 Later it became the means of various instinctive 

 forms of communication and finally afforded the 

 medium of articulate language. Had it not been for 



