The role of luminance edges in misbinding of color to form

Perceptual misbinding of color during binocular rivalry reveals separate neural representations of color and form followed by a neural binding process. The misbinding shows that the neural representation of color from a suppressed form can be expressed within a non-retinotopic location within the dominant form. Misbinding during rivalry is known to be affected by luminance edges within the stimulus: increasing luminance-contrast at edges decreases perceptual misbinding (Hong, S.W. & Shevell, S.K. (2006). Resolution of binocular rivalry: Perceptual misbinding of color. Visual Neuroscience, 23, 561-566.). Previous work, however, did not address the question of whether misbinding depends on equiluminance (i) in the eye of the suppressed form, which contributes the misbound color to the dominant form from the opposite eye, or (ii) in the eye of the dominant form, which incorporates the misbound color. This study answered this question. Misbinding of the chromatic response from a suppressed form that contains high luminance-contrast shows that location information provided by luminance-contrast edges does not inhibit misbinding of color to a non-retinotopic location within an equiluminant form presented to the opposite eye. If filling-in of color is constrained within regions defined by luminance edges, these edges must be perceived; retinal encoding of luminance edges by itself is not sufficient to constrain the perceived location of color.