n neural terms, we can only
repeat what was said before, that perception is the next response
after sensation, being a direct response to a certain combination of
sensations, and being in its turn the stimulus, or part of the
stimulus, that arouses a motor adjustment, as it may also be the
stimulus to recall of previously observed facts. In more psychological
terms, we can say that sense perception is closely bound up with
sensation, so that we seem to see the fact, or hear it, etc.; we
perceive it as present to the {433} senses, rather than as thought of
or as anticipated. Motor readiness is anticipatory, perception
definitely objective. Motor readiness is an adjustment for something
yet to be, while perception is an adjustment to something already
present.

Practised Perception

A fact perceived for the first time must needs be attended to, in
order that it may be perceived. That is, the first and original
perception of a fact is a highly conscious response. But the
perception of a fact, like any other form of response, becomes easy
with practice; the linkage of stimulus and response becomes stronger
and stronger, till finally the stimulus arouses the perceptive
response almost automatically. The familiar fact is perceived without
receiving close attention, or even without receiving any attention.
While your attention is absorbed in reading or thinking, you may
respond to the sight of the flower in a vase on your table by knowing
it to be there, you may respond to the noise of the passing street car
by knowing what that is, and you may respond to the contact of your
foot with the leg of the chair by dimly knowing what that object is. A
great deal of this inattentive perception of familiar facts is always
going on. Aside from sensation and from some of the reflexes, the
perception of familiar facts is the most practised and the easiest of
all responses.

The laws and sub-laws of learning apply perfectly to practised
perception. The more frequently, the more recently, and the more
intensely a given fact has been perceived, the more readily is it
perceived again. The more a given fact is in line with the mental set
of the moment, the more readily is it perceived. Sometimes it is so
readily perceived that we think we see it when it isn't there. If you
are hunting for a lost knife, anything remotely resembling {434} a
knife will catch your eye and for an instant be perceived as the
missing object.

The principle o