an
strengthen the recollection of that particular fact; on the contrary, it
may grow weaker, in the absence of any record of it. But if I touch ice
to-day and again find it cold, the association is repeated, and the
memory of it becomes stronger. And, by this very simple process of
repetition of experience, it has become utterly impossible for us to
think of having handled ice without thinking of its coldness. But, that
which is, under the one aspect, the strengthening of a memory, is,
under the other, the intensification of an expectation. Not only can we
not think of having touched ice, without feeling cold, but we cannot
think of touching ice, in the future, without expecting to feel cold. An
expectation so strong that it cannot be changed, or abolished, may thus
be generated out of repeated experiences. And it is important to note
that such expectations may be formed quite unconsciously. In my dressing
room, a certain can is usually kept full of water, and I am in the habit
of lifting it to pour out water for washing. Sometimes the servant has
forgotten to fill it, and then I find that, when I take hold of the
handle, the can goes up with a jerk. Long association has, in fact, led
me to expect the can to have a considerable weight; and, quite unawares,
my muscular effort is adjusted to the expectation.

The process of strengthening generic memories of succession, and, at the
same time, intensifying expectations of succession, is what is commonly
called _verification_. The impression B has frequently been observed to
follow the impression A. The association thus produced is represented as
the memory, A -> B. When the impression A appears again, the idea of B
follows, associated with that of the immediate appearance of the
impression B. If the impression B does appear, the expectation is said
to be verified; while the memory A -> B is strengthened, and gives rise
in turn to a stronger expectation. And repeated verification may render
that expectation so strong that its non-verification is inconceivable.

FOOTNOTES:

[24] It is not worth while, for the present purpose, to consider
whether, as all nervous action occupies a sensible time, the duration of
one impression might not overlap that of the impression which follows
it, in the case supposed.

[25] We give no name to faint memories; but expectations of like
character play so large a part in human affairs that they, together with
the associated emotions of pleas