214 Animal Intelligence 



each time the food which resulted, and finally to see whether, 

 having failed before the tuition, he would succeed after it. 

 This sounds very simple, but such experiments are hard to 

 carry out satisfactorily. If you try the animal enough times 

 by himself to make quite sure that he will not of himself hit 

 upon the act, you are likely to form in him the habit of 

 meeting the particular situation in question with total dis- 

 regard. His efforts having failed so often may be so in- 

 hibited that you could hardly expect any tuition to give 

 them new life. The matter is worse if you add further 

 enough trials to assure you that your attracting his atten- 

 tion to it has been unavailing. On the other hand, if you 

 take failure in five or ten minutes to mean inability, and 

 from subsequent success after imitation argue that imitation 

 was efficient, you have to face the numerous cases where 

 animals which have failed in ten minutes have succeeded in 

 later unaided trials. With dogs and cats this does not much 

 matter, because they are steady performers, and their conduct 

 in one short trial tells you what to expect with some proba- 

 bility. But the monkeys are much more variable and are 

 so frequently distracted that one feels much less confidence 

 in his predictions. Moreover, you cannot be at all sure of 

 having attracted a monkey's attention to an object unless he 

 does touch it. Suppose, for example, a monkey has failed 

 to even touch a bar though you have put a bit of food on it 

 repeatedly. It is quite possible that he may look at and 

 take the food and not notice the bar, and the fact that after 

 such tuition he still fails to push or pull the bar may mean 

 simply that it has not caught his notice. I have, therefore, 

 preferred in most cases to give the animals only a brief 

 period of trial to test their ability by their own unaided 

 efforts and to omit the attempts to test the efficacy of at- 

 tracting their attention to the vital point in the mechanism. 



