There is common consensus now that color-defined motion can be
perceived by the human visual system. For global motion integration tasks
based on isoluminant random dot kinematograms conflicting evidence exists,
whether observers can (Ruppertsberg et al., 2003) or cannot (Bilodeau & Faubert, 1999) extract a common motion direction for stimuli
modulated along the isoluminant red-green axis. Here we report conditions,
in which S-cones contribute to chromatic global motion processing. When
the display included extra-foveal regions, the individual elements were
large (∼0.3°) and the displacement was large (∼1°),
stimuli modulated along the yellowish-violet axis proved to be effective
in a global motion task. The color contrast thresholds for detection for
both color axes were well below the contrasts required for global motion
integration, and therefore the discrimination-to-detection ratio was
>1. We conclude that there is significant S-cone input to chromatic
global motion processing and the extraction of global motion is not
mediated by the same mechanism as simple detection. Whether the
koniocellular or the magnocellular pathway is involved in transmitting
S-cone signals is a topic of current debate (Chatterjee & Callaway,
2002).