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David Nguyen-Tri, Jocelyn Faubert; Chromatic motion perception is facilitated by static luminance texture. Journal of Vision 2004;4(8):552. doi: 10.1167/4.8.552.
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© ARVO (1962-2015); The Authors (2016-present)
It has been argued that the color system cannot process motion because dynamic luminance noise can mask chromatic motion. This has led to the suggestion that the ability to discriminate chromatic motion direction in the presence of static luminance masks is due to the mask's weakness. In Experiment 1, a stationary plaid pattern was added to a 0.5 CPD chromatic grating drifting at 8?/sec. The perceived speed of chromatic motion was assessed at different plaid contrasts and spatial frequencies. An increase in the perceived speed of chromatic motion with increasing levels of plaid contrast was observed. This increase is most evident at spatial frequencies of 2 CPD. In Experiment 2, the effect of the plaid on the perceived speed of achromatic motion was assessed. An increase in perceived speed with increasing levels of plaid contrast also occurred for achromatic motion. In Experiment 3, the effect of increasing the contrast of flickering plaids of different spatial frequencies on the ability to discriminate direction of motion was assessed. At 4 CPD and 0.5 CPD, increasing contrast had no effect on observers' ability to discriminate direction of motion. At 1 and 2 CPD, increasing levels of plaid contrasts resulted in a decrease in the ability to discriminate direction of motion. We conclude that the ability to discriminate the direction of chromatic motion in the presence of static luminance masks is not due to the masks' weakness, as increasing levels of plaid contrasts resulted in increased perceived speeds. We also conclude that stationary luminance texture facilitates chromatic motion perception by providing additional spatial information to assess the displacement of the chromatic grating.
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