animals.* For example: you put a hungry
animal, say a cat, in a cage which has a door that can be opened by
lifting a latch; outside the cage you put food. The cat at first dashes
all round the cage, making frantic efforts to force a way out. At last,
by accident, the latch is lifted and the cat pounces on the food. Next
day you repeat the experiment, and you find that the cat gets out much
more quickly than the first time, although it still makes some random
movements. The third day it gets out still more quickly, and before long
it goes straight to the latch and lifts it at once. Or you make a model
of the Hampton Court maze, and put a rat in the middle, assaulted by the
smell of food on the outside. The rat starts running down the passages,
and is constantly stopped by blind alleys, but at last, by persistent
attempts, it gets out. You repeat this experiment day after day; you
measure the time taken by the rat in reaching the food; you find that
the time rapidly diminishes, and that after a while the rat ceases to
make any wrong turnings. It is by essentially similar processes that we
learn speaking, writing, mathematics, or the government of an empire.

* The scientific study of this subject may almost be said to
begin with Thorndike's "Animal Intelligence" (Macmillan,
1911).

Professor Watson ("Behavior," pp. 262-3) has an ingenious theory as to
the way in which habit arises out of random movements. I think there is
a reason why his theory cannot be regarded as alone sufficient, but it
seems not unlikely that it is partly correct. Suppose, for the sake of
simplicity, that there are just ten random movements which may be made
by the animal--say, ten paths down which it may go--and that only one of
these leads to food, or whatever else represents success in the case in
question. Then the successful movement always occurs during the animal's
attempts, whereas each of the others, on the average, occurs in only
half the attempts. Thus the tendency to repeat a previous performance
(which is easily explicable without the intervention of "consciousness")
leads to a greater emphasis on the successful movement than on any
other, and in time causes it alone to be performed. The objection to
this view, if taken as the sole explanation, is that on improvement
ought to set in till after the SECOND trial, whereas experiment shows
that already at the second attempt the animal does better than the
first time. Somet