The processes of vision.

The reaction of the nervous system to stimulation by light is far from passive. The eye and brain do not act as a camera or a recording instrument. Neither in perceiving, nor in remembering is there any enduring copy of the optical input. In perceiving, complex patterns are extracted from that input and fed into the constructive processes of vision, so that the movements and the inner experience of the perceiver are usually in good correspondence with his environment. Visual memory differs from perception because it is based primarily on stored rather than on current information, but it involves the same kind of synthesis.