Neural correlates of colour categories.

This study used an electrophysiological marker of visual detection to investigate adults' processing of colour difference. Event-related potentials were collected from the identical colour (green: G0) presented as the frequent or infrequent stimulus within different colour contexts. Critically, we compared differences within the same colour category (G0 vs. green: G1) to differences between colour categories (G0 vs. blue and G0 vs. red). All differences showed a change-related positivity with similar scalp distribution. It was, however, not simply the magnitude of colour difference that reduced the latencies of the change-related positivity. A change in colour category without a magnitude difference also reduced latency of the event-related potential. Thus, for the first time we report an independent neural correlate of a colour category.