An investigation of linear separability in visual search for color suggests a role of recognizability

Visual search for color is thought to be performed either using color-opponent processes, or through the comparison of unique color categories. In the present study, we investigate these theories by using displays with a red or green hue, but varying levels of saturation. The linearly inseparable nature of this display makes search for the midsaturated target inefficient. A genetic algorithm was employed, which evolved the distractors in a search display to reveal the processes that people use to search color. Results show that participants were able to search within only midsaturated red items, but not within only midsaturated green items, providing evidence for color categories, as in English there is a basic color label for midsaturated red (i.e., pink), but not for midsaturated green. A follow-up experiment revealed that it was possible to search within midsaturated green items if the exact target color was primed before each trial. We therefore suggest that both priming and a unique color category increase the recognizability of the target color, which has been speculated to increase visual search performance.