54 Animal Intelligence 
order. On the other hand, if the animal fails to rise above 
the type in his dealings with the boxes, the observer should 
confess that his opinion of the animal’s intelligence may 
have been at fault and should look for a correction of it. 
We have in these time-curves a fairly adequate measure 
of what the ordinary cat can do, and how it does it, and in 
similar curves soon to be presented a less adequate measure 
of what a dog may do. If other investigators, especially 
all amateurs who are interested in animal intelligence, will 
take other cats and dogs, especially those supposed by own- 
ers to be extraordinarily intelligent, and experiment with 
them in this way, we shall soon get a notion of how much 
variation there is among animals in the direction of more or 
superior intelligence. The beginning here made is meager 
but solid. The knowledge it gives needs to be much ex- 
tended. The variations found in individuals should be 
correlated, not merely with supposed superiority in intel- 
ligence, a factor too vague to be very serviceable, but with 
observed differences in vigor, attention, memory and muscu- 
lar skill. No phenomena are more capable of exact and 
thorough investigation by experiment than the associations 
of animal consciousness. Never will you get a better 
psychological subject than a hungry cat. When the crude 
beginnings of this research have been improved and re- 
placed by more ingenious and adroit experimenters, the 
results ought to be very valuable. 
Surely every one must agree that no man now has a right 
to advance theories about what is in animals’ minds or to 
deny previous theories unless he supports his thesis by 
systematic and extended experiments. My own theories, 
soon to be proclaimed, will doubtless be opposed by many. 
I sincerely hope they will, provided the denial is accompa- 
nied by actual experimental work. In fact, I shall be tempted 
