Color segregation and visual search.

Abstract

Visual search of color-coded alphanumeric displays was investigated by reaction time methods. The task was to indicate the alphanumeric class of a target item, singled out by appearing in a designated color which varied across trials. Mean reaction time increased with both the number of colors and the number of items in the displays. When same-colored noise items appeared in spatial proximity (organized displays), mean reaction time was a linear function of the number of colors for each level of number of items, and effects of the two factors were additive. For displays constructed by random assignment of colors to individual noise items (scrambled displays), temporal effects of the same factors showed strong interaction. Search times for scrambled displays were predictable from search times for organized displays by use of subjective estimates of the number of phenomenally separate groups of displayed items. The results suggest that visual search for items in the target color consisted in sequentially examining groups of same-colored items, unitized in accordance with Gestalt principles of proximity and similarity, until a unit in the target color was found.