Color-ambiguity Matching

[摘要] Classical color matching reveals physically different lights that appear identical. For example, a mixture of 550+670 nm lights appears identical to 580 nm light viewed alone. The explanation is that the physically different lights result in identical neural responses so must be indistinguishable. Note this explains why the lights match each other, though not their perceived hue. This principle is extended here to neural representations of color that are ambiguous and thus perceptually unstable: two lights with identical but ambiguous neural representations match each other even though their hue can vary. This is color-ambiguity matching. METHODS/RESULTS: Ambiguous chromatic neural representations were generated using a form of interocular-switch rivalry (aka stimulus rivalry; Logothetis, Leopold & Sheinberg, Nature,1996). Two binocularly rivalrous chromaticities were swapped between the two eyes about 7 times/second. This resulted in a sustained percept for over 1.5 sec (>10 eye swaps) of one color and then the other color. Further, two such ambiguous representations, one above a fixation point and one below it, usually were the same color (far above chance, p< 0.001). Although their color changed regularly, both appeared the same. Importantly, a control with an ambiguous representation above fixation and a nonrivalrous stable representation below showed that the stable color (below) did not directly facilitate the same color above. CONCLUSION: Two separate stimuli that generate identical but ambiguous neural representations become grouped, even though the resulting color is unstable. Like classical color matching, the neural representations establish a match without specifying the perceived hue, which fluctuates over time. Note grouping by identical ambiguous representations occurs prior to perceptual resolution of the neural ambiguity. This is unlike the typical assumption that the color seen determines grouping, as in resolution of the correspondence problem in ambiguous apparent motion in which grouping by color establishes motion direction.

[学科分类] 眼科学