200 



Animal Intelligence 



black being in front (October 25-29). The reaction to the 

 ' yes ' signal was perfect from the start. The progress with 

 the ' no ' signal is shown in Fig. 30, d. 



I then tried him with an apparatus externally of different 

 size, shape and color from that so far used, showing as the 

 'yes' signal a brown card and as the 'no' signal a white 

 and gold card one half inch farther back in the apparatus. 

 The ' yes ' signal was practically perfect from the start. His 

 progress with the ' no ' signal is shown in Fig. 30, e. 



I then tried a still different arrangement for exposure, to 

 which, however, he did not give uniform attention. 



I then tried cards i and 101, 101 being in front and i in 

 back, i was the ' yes ' signal. c Yes J responses were perfect 

 from the start. For * no ' responses see Fig. 30, /. I then put 

 the 'yes' signal in front and the 'no' signal behind. 'Yes' 

 responses perfect ; for ' no ' responses see Fig. 30, /, a. 



From now on I arranged the exposures in such a way that 

 there was no difference between the ' yes ' and ' no ' signals 

 in distance or surroundings. 



The following list shows the dates, signals used, and the 

 figures on page 199 presenting the results. Where there is 

 only one figure drawn, it refers to progress with the 'no' 

 signal, the 'yes' signal being practically perfect from the start. 



TABLE 10 



