1 88 Animal Intelligence 



abundant opportunity to realize that one signal meant 

 food at the bottom of the cage and another none, a monkey 

 would not act from the obvious inference and consistently 

 stay up or go down as the case might be, but would make 

 errors such as would be natural if he acted under the growing 

 influence of an association between sense-impression and 

 impulse or sense-impression and idea, but quite incompre- 

 hensible if he had compared the two signals and made a 

 definite inference. We shall find that, after experience 

 with several pairs of signals, the monkeys yet failed, when 

 a new pair was used, to do the obvious thing to a rational 

 mind; viz., to compare the two, think which meant food, 

 and act on the knowledge directly. 



The methods one has to take to get them to do anything, 

 their general conduct in becoming tame and in the ex- 

 periments throughout, confirm these conclusions. The 

 following particular phenomena are samples of the many 

 which are inconsistent with the presence of reasoning as 

 a general function. No. i had learned to open a door by 

 pushing a bar around from a horizontal to a vertical posi- 

 tion. The same box was then fitted with two bars. He 

 turned the first bar round thirteen times before attempting 

 to push the other bar around. In box LL all three monkeys 

 would in the early trials do one or two of the acts over and 

 over after they had once done them. No. i, who had 

 learned to pull a loop of wire off from a nail, failed thereafter 

 to pull off a similar loop made of string. No. i and No. 3 

 had learned to poke their left hands through the cage for 

 me to take and operate a chute with. It was extremely 

 difficult to get either of them to put his right hand through 

 or even to let me take it and pull it through. 



A negative answer to the question "Do the monkeys 

 reason?" thus seems inevitable, but I do not attach to 



