transaction with a child of 22 months with a loud word, if he is 

 ready, he may return his version of the word or a slight variant; 

 if one replies with another variant the child rephes with still a 

 third, or even suddenly with a new word, and so on back and 

 forth in a transactional vocal dance. Or one may reply to a child 

 who invites such an exchange to begin. Such exchanges seem 

 to function as rewards of themselves, and hence the name, 

 "transactional drive." This phenomenon is more than mere me- 

 chanical slavish mimicry. It seems to aid in perfecting pronun- 

 ciation, increases vocabulary, increases the bonds with other 

 persons, serves to substitute the "consensus-dictionary" words 

 for the private baby words, and is thus essential to learning a 

 language of one's own species. It is thus that the child "becomes 

 human." 



As the child ages and grows, the exchanges lengthen, and the 

 time during which each member of the dyad is quiet while the 

 other speaks becomes longer, until finally for a half hour or so, 

 I am lecturing and you are at least quiet, if not listening. 



How does all of this relate to modern dolphins, porpoises, and 

 whales ? From the vast array of scientific facts and theories about 

 our own species, a few of those which I feel are useful in ap- 

 proaching another species to evaluate its intelligence are dis- 

 cussed above. But before I make connections there, let us attenu- 

 ate some interfering attitudes and points of view, some myths 

 not so modern; these interfering presumptions can be stated as 

 follows : 



(i) No animal has a language comparable to a human language. 



(2) No animal is as intelHgent as man. 



(3) Man can adapt himself to any environment quite as well as any 

 animal. 



(4) Intelligence and intellect can be expressed only in the ways man 

 expresses or has expressed them. 



(5) All animal behavior is instinct-determined. 



(6) None of man's thought and behavior is so determined. 



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