An Evolutionary Hypothesis for White's Illusion: Constant Percentage Correction and Modern Individual Variation

원문 초록

White's illusion is a striking demonstration of context-dependent brightness and lightness perception. In earlier work, we developed a forward translucency-based formula capable of producing approximately constant perceived appearance across varying backgrounds. While validating that formulation, we observed a notable population-level pattern: individuals selected slightly different correction percentages for "constant perception," while the population average remained remarkably stable across experiments. In this paper, we propose an evolutionary hypothesis for this phenomenon. We suggest that a simple constant-percentage correction function could have emerged as an adaptive mechanism for maintaining useful material and reflectance judgments under variable illumination. Under this interpretation, the stability of the population mean may reflect a conserved perceptual mechanism, whereas individual differences may reflect learning, adaptation, or variation around a shared computational response. Using a modification of our previously published forward model, we show that White's illusion can be reproduced by applying a constant-percentage correction to background luminance. The model therefore provides a compact computational account of the observed population-level regularity and motivates a testable evolutionary interpretation of individual variation in contextual lightness judgments.