TITLE OF ARTICLE: Color Perception: Seeing With the Brain

              AUTHOR: Montgomery, Geoffrey
              JOURNAL NAME: Discovery
              DATE: Dec., 1989
              PAGE(S) 52-59
              ACCESSION NUMBER: 05
              SENSE(S): Sight

              ABSTRACT: Provides theories of the phenomenon of
              color constancy, that is, how our perception of the
              color of an object does not alter even when that
              object is bathed in the light of a different color.
              Edwin Land postulated that the we do not sense a
              color in isolation. We always compare it with its
              background. We calculate the center and surround
              ratios of light intensity of the three wavelength
              bands of red, blue and green. <LK105 SIGHT>

              A major theory discussed is trichromatic theory of
              color. This holds that the eyes are primarily three
              color cameras with separate receptors receiving and
              measuring the amount of red, green and blue light
              bouncing off an object.

              The discoveries and theories of Edwin Land
              (inventor of the instant camera), James Maxwell,
              Isaac Newton, John Dalton, Thomas Young, Jeremy
              Nathan, and David Hogness are discussed. Land's
              theories, however, if true, required a special kind
              of nerve cell in the visual system.

              Researchers found evidence to back Land's
              theory in research on goldfish retinas. Later work
              indicated further evidence in the primary visual
              cortex (or V1) at the lower back of the skull or
              primates. Another area, called "V4" or "blob-V4"
              was later discovered to better account for color
              constancy.

              The most recent research, however, suggests great
              complexity in how color perception works. Some
              researchers claim it presupposes a network of
              interconnected "blobs," Researchers do not all
              agree on how color perception works precisely. Many
              details and inconsistencies have yet to be worked
              out. <LK150 NEUROLOGICAL ARTICLE THEMES>

RESEARCHERS QUOTED IN ARTICLE:

              Land, Edwin. Retired head of Polaroid and now runs
              a non-profit lab called the Rowland Institute of
              Science. Postulated many theories of color
              perception which he or others later confirmed.

              Van Essen, David. Caltech researcher who believes
              in the network theory of "blobs" in color
              perception.

              Wiesel, Torsten. Rockefeller University researcher
              and Nobel Prize winner who, with David Hubel of
              Harvard University, confirmed and extended many of
              Land's theories on color perception.


