Color similarity in visual search

In the present study, we investigated the role of phenomenologically perceived color differences between stimuli in determining visual search efficiency. We contrasted this with predictions based on the categorical color status, as proposed by Wolfe's Guided Search 2 model. We first asked participants to rate the color similarity of each pair of stimuli (pairwise comparison). The results were combined using multidimensional scaling to produce a similarity metric, which was subsequently used to define stimulus similarities for two visual search experiments. The results demonstrate that the time required by participants to find a target is more adequately explained by the perceived similarity of colors than by color categories.