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. 
