258 EDWARD J. KEMPF, M. D. 



but ever since F punished C when B, C and F were caged to- 

 gether, B punishes her and she submits to his aggressions. 



D, E and F are about matured males. E is the largest and 

 most powerful and dominates the band. D is next in strength 

 and dominates all but E. That is, he punishes all but E. F is 

 not liked by the other monkeys, and they all have preferences 

 for some other monkey than F. F dominates A, B and C. 



The studies were conducted in a basement where they live 

 in three cages. Besides one or two boxes, a barrel and a chair, 

 there is no other furniture in the room. My presence during 

 the studies could have had very little influence since they all 

 are used to me. They are more or less timid toward me, but 

 pay practically no attention to me when I am quiet and remain 

 at a distance. 



The problem studied was accidentally suggested. The cages 

 are all raised 18-19 cm. from the floor by blocks, one under 

 each corner. There is an aperture about 4 cm. wide and 80 

 cm. long between the flooring of the cages and the lower hori- 

 zontal wooden bar to which the screen is attached. This aper- 

 ture is closed by a movable wooden bar to keep the sawdust 

 in the cage and is easily removed for cleaning the cage and 

 watering. A small wooden box, 25x30x16 cm. happened to be 

 at hand. One evening I noticed some of the monkeys trying 

 to reach to the floor for some peanut shells. It occurred to me 

 to drop a few peanuts into this box and push it up to the cage 

 and see the monkeys reach for the nuts. 



A, B and C were in this cage. They promptly reached through 

 the wires into the box but the distance was too great to reach 

 the peanuts. The bar was then removed and A, B and C im- 

 mediately returned to grab peanuts. B and C returned first 

 and, true to their habits, overlooked the new opening and utilized 

 as before, the nearest wire screen area above the box. They 

 repeatedly reached through the spaces but could not quite 

 touch the nuts. A tried to reach from this place also but was 

 pushed away by B and C, whereupon he tried it lower down 

 and pushed his hand through the horizontal aperture between 

 the floor and the crossbar and then extended his hand into the 

 box containing the nuts. He chuckled his delight as he drew 

 out the nut. Immediately B and C tried this aperture and 

 succeeded in reaching the nuts. (Objective learning through 



