48 Animal Intelligence 
they licked themselves, and of cats 6, 2 and 4, which were 
let out when they scratched themselves, are interesting be- 
cause they show associations where there is no congruity 
(no more to a cat than to a man) between the act and the 
result. One chick, too, was thus freed whenever he pecked 
at his feathers to dress them. He formed the association, 
and would whirl his head round and poke it into his feathers 
as soon as dropped in the box. There is in all these cases 
a noticeable tendency, of the cause of which I am ignorant, 
-te diminish the act until it becomes a mere vestige of a 
‘lick or scratch. After the cat gets so that it performs the 
,act soon after being put in, it begins to do it less and less 
Enel The licking degenerates into a mere quick 
turn of the head with one or two motions up and down with 
tongue extended. Instead of a hearty scratch, the cat 
waves its paw up and down rapidly for an instant. More- 
over, if sometimes you do not let the cat out after this 
feeble reaction, it does not at once repeat the movement, 
as it would do if it depressed a thumb piece, for instance, 
without success in getting the door open. Of the reason for 
this difference I am again ignorant. 
Previous experience makes a difference in the quickness 
with which the cat forms the associations. After getting 
out of six or eight boxes by different sorts of acts the cat’s 
general tendency to claw at loose objects within the box is 
strengthened and its tendency to squeeze through holes 
and bite bars is weakened ;' accordingly it will learn associa- 
tions along the general line-of the old more quickly. Fur- 
ther, its tendency to pay attention to what it is doing gets 
strengthened, and this is something which may properly 
be called a change in degree of intelligence. A test was 
made of the influence of experience in this latter way by 
putting two groups of cats through I (lever), one group 
