n they do not
occur, and often, when they do occur, they follow the perception of
the fact, being aroused by that perception and not constituting it.

Sometimes images are certainly aroused during the perception of a
fact, and, blending with the present rather vague sensation, add color
and filling to the picture.

Here is an instance of this which I once observed in myself, in spite
of the infrequency of my visual images. Approaching a house through a
wide field one winter night, and seeing a lamp shining out of a window
towards me, I seemed to see the yellowish light touching the high
spots in the grass around. I was surprised that the lamp should carry
so far, and the next instant saw that the light spots on the ground
were small patches of snow, lighted only from the clouded sky; and at
this the yellow tinge of the spots vanished. I must have read the
yellow color into them to fit the lamplight. The yellow was an image
blending with the actual sensation. Colors tacked on to a seen object
in this way are sometimes called "memory colors".

When this instance is considered carefully, however, it does not by
any means indicate that the image produced the perception. I responded
to the pair of stimuli--lamp shining towards me and light spots around
me--by perceiving the spots as lighted by the lamp; and the color
followed suit. I next saw the spots as snow, and the color vanished.
It was a case of trial and error perception, with color images
conforming to the perception.

Perception does not essentially consist in the recall of {427} images,
but is a different sort of response--what sort, we have still to
consider.

Perception and Motor Reaction

Possibly, we may surmise, perception is a motor response, completely
executed or perhaps merely incipient, or at least a readiness for a
certain motor response. This guess is not quite so wild as our
customary sharp distinction between knowing and doing might lead us to
think. When we say that reacting to a thing in a motor way is quite
different from merely seeing the thing, we forget how likely the child
is to do something with any object as soon as he sees what it is. We
forget also how common it is for a person, in silently reading a
word--which is perceiving the word--to whisper it or at least move his
lips. To be sure, persons who read a great deal usually get over this
habit, as the child more and more inhibits his motor response to many
seen objects. But may i