Abstract
Whether fundamental visual attributes, such as color, motion and shape, are analyzed separately in specialized pathways has been one of the central questions of visual neuroscience. Although recent studies have revealed various forms of cross-attribute interactions, including significant contributions of color signals to motion processing, it is still widely believed that color perception is relatively independent of motion processing. A challenge to this belief is ‘motion-induced color mixing’ (Nishida et al., 2007, Current Biology), in which moving bars, the color of which alternates between two colors (e.g., red and green), are perceived as the mixed color (e.g., yellow) even though the two colors are never superimposed on the retina. This phenomenon suggests that color signals may be integrated not only at the same retinal location, but also along a motion trajectory, as in the case of trajectory integration of pattern signals (Nishida, 2004, Current Biology). It is possible that this neural mechanism helps us to see veridical colors for moving objects by reducing motion blur. In line with this hypothesis, we also found ‘motion-induced color segregation’ (Watanabe & Nishida, 2007, Journal of Vision), in which temporal alternations of two colors on the retina are perceptually segregated more veridically when they are presented as moving patterns rather than as stationary alternations at the same rate. Additionally, this improvement of objective temporal resolution is similar to subjective motion deblurring (Bedell & Rott, 1996, Current Biology) in that both effects are enhanced when an observer views a stationary object while making a pursuit eye movement, in comparison with when an observer views a moving object without moving eyes (Terao et al., 2008, VSS).