130 HUMAN BIOLOGY 



the former in the variety and skill of instrumental adapta- 

 tions. When it comes to the seeking out, creation, or con- 

 struction of tools, pertinent records although few are 

 obviously important. By Kohler* it has been reported for 

 the chimpanzee that a branch may be broken from a con- 

 venient tree to serve as means of reaching and securing 

 distant food. This author also reports for the chimpanzee 

 the joining of two sticks, either of which alone was too 

 short to meet the animal's need. The sticks were hollow and 

 they were of such size that it was possible for the chimpanzee 

 to insert the end of one into the aperture of the other. 

 In this instance clearly the subject had at hand the materials 

 of a serviceable tool, but except as brought into the relation 

 which we have described these materials remained valueless 

 as aids to the solution of the problem of obtaining food. 

 Kohler supphes yet another type of observation which 

 clearly belongs in this category, for he describes a chim- 

 panzee as reducing the size of one end of a stick so that it 

 might be inserted into the hollow end of another, that thus 

 the two might be constituted a serviceable instrument. 



All of these adaptive activities may be classified as tool- 

 making, since it appears that the ape is endeavoring so to 

 manipulate or modify a portion of its environment as to 

 render it serviceable in the solution of a certain practical 

 problem. As we intimated above, observations of this sort 

 are relatively few and we may only tentatively conclude 

 that the anthropoid apes are generally capable of such 

 expressions of what in ourselves we should unhesitatingly 

 call constructive imagination. If however the chimpan- 

 zee, without human suggestion, tuition, or other definite aid, 

 modifies environmental objects for certain definite purposes, 

 it would be scarcely more reasonable to deny constructive 

 imagination in it than in man. Our tentative conclusion, 

 based largely on unpublished data, is that the apes possess 

 creative imagination. 



Investigation of memory and related processes in monkeys 

 and apes has made it abundantly clear that psychobiologi- 

 cally there is a vast gulf between lemur and ape and even 

 between monkey and ape, for it is only in the latter that 



*Chap. 4 and 5. 



