SOUNDS AND SPEECH 55 



cage and operated at will by the experimenter. Each day at 

 a stated hour the observer would place the apparatus in 

 position, having loaded it in advance with six pieces of ba- 

 nana each about an inch in length, and would call Chim to 

 attention. With him beside the apparatus and watching 

 intently, the sound "co, co" was made distinctly and em- 

 phatically a few times, whereupon a piece of banana suddenly 

 appeared on the table. Sometimes Chim was allowed to 

 have the banana, and again the experimenter took it in order 

 to continue his interest and attention, and if possible increase 

 his eagerness for the reward. Occasionally this procedure 

 induced certain lip movements seemingly in imitation of 

 those of the experimenter. Rarely, and as if by accident, 

 Chim would make a sound. Certain slight and unconvincing 

 intimations of attempts to make sounds when facing this 

 apparatus appeared. The training test was continued for 

 several weeks with regularity but, apart from the above 

 encouraging signs, with negative results. 



Another type of device consisted of a board on which was a 

 small box hinged on one side and provided with a spring 

 which when released would raise the box and uncover a 

 banana. This box had a wire mesh cover through which 

 Chim could see the banana. 



Having placed a banana in the apparatus the experimenter 

 would take it into the cage and having secured Chim 's atten- 

 tion, would make the sound "na, na" distinctly and em- 

 phatically a few times, thereupon releasing the apparatus so 

 that the banana was uncovered. Usually the observer 

 seized the banana and began to eat it, thus intensifying the 

 eagerness of the animal. In the second or third trial Chim 

 was allowed to get the banana and eat it whether or not he 

 made a sound. This method also, although tried until 



