CHAPTER IV 

 THE EVOLUTION OF INTELLIGENCE 



JAMES ROWLAND ANGELL 



PRESIDENT OF YALE UNIVERSITY 



It may be assumed without argument that evolution has 

 actually occurred within the field of intelligence, as it has 

 within the field of organic structure, and I shall proceed at 

 once to examine the major features of the process. It will be 

 convenient to distinguish in such an analysis between the de- 

 velopment of intelligence in animals and the corresponding 

 development in man. This distinction is not for a moment 

 intended to postulate any fundamental difference between hu- 

 man and animal intelligence, for this is one of the questions 

 which can only be confidently answered, if at all, after adequate 

 examination of the available data. It is simply a device for 

 expediting access to two great groups of facts which present 

 certain practical distinctions. 



In the field of cosmic and stellar evolution, we have such 

 facts as are disclosed to us through telescopic and spectro- 

 scopic examination of the heavenly bodies, with their convinc- 

 ing indications of evolutionary processes extending over un- 

 imaginable epochs of time and over equally abysmal areas of 

 space. In the case of the crust of our own earth, geology 

 similarly brings to our knowledge evidence of slow, age-long 

 changes, as a result of which the present superficial character- 

 istics of the earth's surface have been produced, together with 

 its climatic and other peculiarities. Again, there is convincing 



