MENTAL EVOLUTION IN THE PRIMATES I3I 



clear indications of reproductive memory images or their 

 functional equivalents and of the germs of constructive 

 imagination appear. 



Without reproductive imagination an animal presumably 

 cannot adapt selectively; w^ithout creative imagination it is 

 difficult to see how it could construct tools. It is our tentative 

 conclusion from such observational data as we have knowl- 

 edge of, that man's marvelous power of adaptation through 

 control of his environment is presaged in the anthropoid 

 apes. He is not the sole possessor of constructivity. 



Logically this discussion should be extended to considera- 

 tion of behavioral indications of the evolution of the processes 

 of abstraction and generaHzation, but for practical reasons 

 this is undesirable. Observational data, as it happens, are 

 few and of uncertain value. Already we have presented 

 the grounds on which we base the affirmation of the existence 

 of both reproductive and creative imaginal processes in the 

 apes and with less certainty in the monkeys. We do not feel 

 justified in devoting additional space to this section by 

 considering such evidences of the beginnings of abstraction 

 and generalization as may be found in the accounts of 

 primate behavior. It must suffice to state that not only are 

 the evidences meager, but they very definitely suggest that 

 no existing primate, except man, is capable of anything 

 beyond the most rudimentary, or, developmentally con- 

 sidered, the most primitive forms of abstraction and generaH- 

 zation. This condition is so importantly related to our next 

 topic, language and the use of symbols, that it will neces- 

 sarily receive certain further attention in that connection. 



LANGUAGE AND THE FINAL DOMINANCE OF SPEECH 



Thinking, except in terms of concrete experience, depends 

 upon symbols and is facihtated by them. Doubtless it is 

 beside the point and indicates a certain limitation of insight 

 to inquire whether thinking prepared the way for talking 

 or the reverse — whether function anticipates structure! 

 Undeniably, symboHsm is of extreme importance in human 

 life. It therefore is necessary to ask in this discussion of 

 evolutionary process, whether there appear in birds or 

 mammals languages comparable in functional essentials, 



