2O2 Animal Intelligence 



No. 2 did come to differentiate these two signals. The record 

 of his progress is given in Fig. 31 by A and A. 



I then made a second attempt with the exposing appara- 

 tus, using cards 2 and 102 (November 6, 14-21). No. 2 

 did react to my movements in pulling the string but in over 

 100 trials made no progress in the direction of a differential 

 reaction to the ' no ' signal. I then tried feeding him at each 

 signal, feeding him at the bottom of the cage as usual when 

 I gave the ' yes ' signal and at the top when I gave the ' no ' 

 signal. After a hundred trials with the 'no' signal there 

 was no progress. 



I then abandoned again the exposing apparatus and used 

 as signals the ordinary act of taking food with my left hand 

 (yes) and the act of moving my left arm from my right side 

 round diagonally (swinging it on my elbow as a center) and 

 holding the hand, after taking the food, palm up (no) (No- 

 vember 26, 27, 1900). No. 2 did come to differentiate these 

 signals. His progress is given in the diagram in Fig. 31 en- 

 titled ' Palm up 7 (). 



I next used (November 27, 1900) as the 'yes' signal the 

 same act as before and for the ' no ' signal the act of holding 

 the food just in front of the box about four inches below 

 the edge. No. 2's progress is shown in Fig. 31 in the dia- 

 gram entitled 'low front' (C and Ci). 



I next used (November 27-30) the same movement for 

 both ' yes ' and 'no' signals save that as the ' yes ' signal I took 

 the food from a brown pasteboard box 3 by 3 by 0.5, and as 

 the ' no ' signal I took it from a white crockery cover two 

 inches in diameter and three eighths of an inch high which 

 was beside the box but three inches nearer me. No. 2's 

 progress is shown in Fig. 31 in the diagram entitled 'Box 

 near ' (D). 



I next used for the ' yes ' signal the familiar act and for the 



