332. 



THE QUARTERLY REVIEW OF BIOLOGY 



First, the chimpanzee strongly dislikes 

 the strain of situations which call upon 

 his inventive faculties. The process of 

 invention is visibly and disagreeably 

 arduous for him. His first impulse is to 

 giYe up, or to become angry, if he cannot 

 arrive at a solution by purely physiologi- 

 cal means such as leaping or biting. 

 Characteristic is the fact that if a reaching 

 implement is in line of vision with the 

 desired object, it is usually promptly 

 utilized. If on the other hand, the stick 

 lies behind the .ape's back as he faces the 

 food, it will not be "thought of" or 

 noticed and taken up for a long time, when 

 the experiment is a novelty to the animal 

 being observed; in fact, usually not until 

 after repeated renunciations and recur- 

 rences of desire. Emotions clearly are 

 important, constituting a strong resistive 

 factor. The individuals that meet diffi- 

 cult problems most readily, and carry 

 invention farthest, are evidently those 

 best able to control or inhibit the emo- 

 tions which the prospective goal arouses 

 in them. 



COMPETITION AS A STIMULUS TO INVENTION 



But emotions of another kind can be 

 an impelling influence toward invention. 

 These are the social emotions. His desire 

 for affection, and for approbation from 

 human beings, certainly helps a chimpan- 

 zee to invent tools. In the state of na- 

 ture it is probable that competitive emo- 

 tion — jealousy — is even more stimulating. 

 Significant is Koehler's observation of 

 the behavior of his adult female chimpan- 

 zee when a loaded box or heavy obstacle 

 was placed to prevent her from reaching 

 her food beyond the bars. She was per- 

 fectly capable of moving the obstacle; 

 but the problem weighed on her for two 

 hours. When however one of the young 

 animals began to stray in the direction of 

 the food, from which it was not separated 



by bars, she suddenly seized the heavy 

 box, shoved it out of the way without 

 hesitation, and grasped the prize out of 

 reach of the competitor. Next day she 

 found the solution in one minute. 



The same chimpanzee objected to using 

 sticks for reaching unless they were, so 

 to speak, thrust into her hands by their 

 placement. For half an hour she neg- 

 lected a stick which was close behind her 

 and which, as a retinal image, she saw 

 whenever in aimless irritation she turned 

 around. After a while she stood on the 

 stick. She must have felt it with her 

 sole; but again, as a personality, she re- 

 fused to receive the sense impression. 

 After half an hour a free chimpanzee came 

 near the food. The jealousy which his 

 approach excited was utilized to repress 

 the sulking emotion hitherto displayed; 

 and suddenly the ignored stick was per- 

 ceived, seized, and used to draw in the 

 food. 



The one gorilla tested reacted less emo- 

 tionally, but showed less inventive faculty 

 than the cleverest of the chimpanzees. 



These observations may not throw much 

 light on the question of how far apes 

 possess culture. They do however suggest 

 much as to the psychology which under- 

 lies human culture, and what we are 

 accustomed to term its progress. They 

 indicate that the elimination of the com- 

 petitive factor among men would deprive 

 civilization of one of its principal and 

 perhaps indispensable impulses. They 

 suggest further why the institutions, 

 codes, and ethics of all peoples have so 

 strongly emphasized inhibition; why, for 

 instance, courage — the repression of fear — 

 has always been esteemed a high if not 

 the highest virtue; and why, similarly, 

 all social groups condemn incest. Not 

 that the anthropoid apes set up moral 

 standards. But all human groups do; 

 they have evidently learned, on the basis 



