nd the existence in the past of some
special relation of the recognizer to the recognized, if only that of an
observer. In fact, it is evident that in this mode of recognition we
have the transition from common perception to individual
recollection.[8]

While we may thus distinguish different steps in the process of visual
recognition, we may make a further distinction, marking off a passive
and an active stage in the process. The one may be called the stage of
preperception, the other that of perception proper.[9] In the first the
mind holds itself in a passive attitude, except in so far as the
energies of external attention are involved. The impression here awakens
the mental images which answer to past experiences according to the
well-known laws of association. The interpretative image which is to
transform the impression into a percept is now being formed by a mere
process of suggestion.

When the image is thus formed, the mind may be said to enter upon a more
active stage, in which it now views the impression through the image, or
applies this as a kind of mould or framework to the impression. This
appears to involve an intensification of the mental image, transforming
it from a representative to a presentative mental state, making it
approximate somewhat to the full intensity of the sensation. In many of
our instantaneous perceptions these two stages are indistinguishable to
consciousness. Thus, in most cases, the recognition of size, distance,
etc., takes place so rapidly that it is impossible to detect the two
phases here separated. But in the classification of an object, or the
identification of an individual thing, there is often an appreciable
interval between the first reception of the impression and the final
stage of complete recognition. And here it is easy to distinguish the
two stages of preperception and perception. The interpretative image is
slowly built up by the operation of suggestion, at the close of which
the impression is suddenly illumined as by a flash of light, and takes a
definite, precise shape.

Now, it is to be noted that the process of preperception will be greatly
aided by any circumstance that facilitates the construction of the
particular interpretative image required. Thus, the more frequently a
similar process of perception has been performed in the past, the more
ready will the mind be to fall into the particular way of interpreting
the impression. As G.H. Lewes well remarks,