264 EDWARD J. KEMPF, M. D. 



B immediately dashed to the box and obtained food. E took 

 it from him after a chase. A handful of nuts were dropped into 

 the box. E tried awkwardly to reach them. Finally he reached 

 in with the back of the hand towards the food — D's method — 

 and extracted a nut. After this E learned rapidly. He gradually 

 modified the position of his body until he no longer uses the 

 wires to raise himself but forces his head tightly against the bar 

 or floor and is able to reach the food with either hand. D also 

 abandoned the vertical screen position but still keeps the pos- 

 terior half of his body elevated. Both D and E now place 

 their bodies nearly parallel to the aperture. The tendency is 

 still to use the arm on the off side with the back of the hand 

 facing towards the food in the box unless the hand is extremely 

 extended, when the thumb also reaches the food — the most awk- 

 ward position of the hand for grasping. 



E and D are good specimens of the Macacus rhesus, well 

 developed young adults. That spontaneous subjective learning 

 should be so slow and laborious a process, even in an organism 

 so highly developed as this species of monkey, when trying to 

 adapt well developed movements to a new situation is sur- 

 prising upon first estimation. 



CONCLUSIONS 



The observations seemed to show repeatedly that the follow- 

 ing phenomenon occurred: D was the host of a motive — 

 to acquire food. This motive discharged itself through a mani- 

 fold of more or less incoordinated movements to acquire the 

 food. A novel, accidental association of movements permitted 

 complete expression of the motive. Hence there was a ten- 

 dency to repeat similarly associated movements, eliminate the 

 unnecessary and finally reach a maximum of efficiency whereby 

 the hunger motive could express itself with a minimum of effort. 

 In other words, the motive was the force, the box, etc., the 

 mold, and the repertory of movements the material to be molded. 

 A novel or accidental association of movements finally made the 

 molding possible. 



That is to say, D did not strictly try one movement and 

 then another as a process of elimination of the useless move- 

 ments but more aimlessly seemed to be the host of a stream of 

 force that caused a continuous pressure for expression and ac- 



