color signal integration for color discrimination along a longrange apparent motion trajectory in contrast to the classical view that fundamental visual attributes such as color and motion are independently processed in the visual system eg livingstone and hubel 1987 marr 1982 recent studies have revealed various forms of crossattribute interactions such as averaging of color appearance along the motion trajectory of an object nishida et al 2007 in this study we investigated whether such color signal integration along a motion trajectory can be induced only by motion mechanisms having large receptive fields without simple integration within directionselective neurons with small receptive fields like those in v1 the stimulus consisted of discs with longrange apparent motion along a circular trajectory the stimulus onset asynchrony soa between disc presentations controlled the strength of the apparent motion perception we measured observers sensitivity in detecting color modulation on the discs the results showed that the measured sensitivity was lowest at soas corresponding to the strongest motion perception this can be interpreted as follows color signals were integrated along an apparent motion path and this integration reduced chromatic sensitivity by averaging color signals another experiment that controlled apparent motion perception in a different way also supported this idea however this integration effect seemed to be linked to responses of motion detectors for the apparent motion stimuli not directly to perceptual motion representation in the visual system these results suggest that the human visual system handles color information from retinal inputs regarding moving objects based not only on a retinotopic coordinate but also on objectbased coordinates even when the moving object yields only longrange apparent motion