Abstract
BACKGROUND: Induction with S-cone stimulating patterns can cause striking color shifts (e.g., Monnier & Shevell, 2003). In the present study, we explored whether changing the space-average S-cone stimulation of the inducing pattern, holding the differences in S-cone stimulation between inducing and test chromaticities constant, affected the color shifts. METHODS: Chromatic induction was measured with patterns composed of circles that varied in S-cone stimulation using asymmetric matching. The color appearance of a test ring presented with high and low S-cone stimulating circles was matched by adjusting the hue, saturation, and brightness of a comparison ring presented within a uniform gray (EEW) field. The space-average S-cone stimulation of the test pattern was varied, holding the differences in S-cone stimulation between the inducing and test chromaticities constant. For each inducing pattern, measurements for three test-chromaticities that varied in L/(L+M) were obtained. RESULTS: As previously reported, S-cone inducing patterns can cause relatively large shifts in color appearance. The arrangement of the inducing circles (high-S-cone-adjacent/low-S-cone non-adjacent or vice versa) determined the direction of the color shifts toward higher or lower S-cone stimulation, respectively, independent of the space-average S-cone stimulation of the inducing pattern. The space-average manipulation did affect the three test L/(L+M) chromaticities differently, with a general shift toward lower S-cone matches for the high L/(L+M) test. CONCLUSION: Variations in the space-average S-cone stimulation of the inducing patterns did not alter the overall direction of the color shifts but did affect the magnitude of the shifts for the three test-ring chromaticities that varied in L/(L+M) chromaticities. These measurements suggest an interaction among the different cone-types.