Chromatic assimilation is a shift toward the color of nearby light.
Several studies conclude that a neural process contributes to
assimilation but the neural locus remains in question. Some studies
posit a peripheral process, such as retinal receptive-field
organization, while others claim the neural mechanism follows depth
perception, figure/ground segregation, or perceptual grouping. The
experiments here tested whether assimilation depends on a neural
process that follows stereoscopic depth perception. By introducing
binocular disparity, the test field judged in color was made to appear
in a different depth plane than the light that induced assimilation.
The chromaticity and spatial frequency of the inducing light, and the
chromaticity of the test light, were varied. Chromatic assimilation was
found with all inducing-light sizes and chromaticities, but the
magnitude of assimilation did not depend on the perceived relative
depth planes of the test and inducing fields. We found no evidence to
support the view that chromatic assimilation depends on a neural
process that follows binocular combination of the two eyes'
signals.
Chromatic assimilation measured by temporal nulling: Interaction between the l and s pathways