Chromatic induction: border contrast or adaptation to surrounding light?
Chromatic induction from a surrounding light is measured with an additional remote field outside the surround. Chromatic induction from the surround into a central test field is found to be attenuated by a remote inhomogeneous 'checkerboard', composed of squares at two different chromaticities. A uniform remote field, on the other hand, either at the average or at the most extreme chromaticity of the 'checkerboard', has a weaker effect on chromatic induction than the inhomogeneous field, implying that chromatic contrast within the remote region is a critical factor. The complete set of experiments is accounted for by chromatic contrast gain control: chromatic induction, mediated by a neural signal for contrast at the edge of the test, is attenuated by contrast within the remote region. A contrast gain control set by variation in chromaticity over a broad area can contribute to the stable color appearance of surfaces embedded within complex scenes by minimizing chromatic induction from locally adjacent regions.
Shevell
S K
SK
Department of Psychology, University of Chicago, IL 60637, USA. shevell@uchicago.edu
Wei
J
J
D000221:Adaptation, Ocular / Q000502:physiology*; D003118:Color Perception / Q000502:physiology*; D015350:Contrast Sensitivity / Q000502:physiology*; D006801:Humans; D009903:Optical Illusions / Q000502:physiology; D010364:Pattern Recognition, Visual / Q000502:physiology