Color and Texture Differences in Embedded Target Visual Search Situations

Abstract

This study provides a direct investigation of embedded target visual search situations. The relationships between measures of visual search performance, peripheral visual acuity and ratings of discriminability were determined. The embedded target displays were constructed using a color and a monochrome texture background. They were used in a rating study, in which the production magnitude rating method was used, and in visual search and peripheral acuity experiments. In the first of these, 28 observers rated the discriminability of five color targets from the color background, and of four black and white targets from the monochrome background. There were two visual search experiments. Five observers searched the color background for the color targets, and six searched the monochrome background for the black and white targets. In both experiments, after practice, there were sixty search trials per observer per target. The extent into the periphery, that the five color targets could be seen when the color display was exposed for 0. 3 seconds, was measured for the five observers used in the color search task. The same measurement was made with the black and white stimulus materials for four of the six observers used with the monochrome task.

For the color stimulus materials, a set of simple relationships were found to describe the measures obtained in all three experimental areas. The results with the monochrome texture material did not fit the same equations so well. The equations were based on those developed by Howarth and Bloomfield (1969; Bloomfield and Howarth, 1969) for search situations involving targets that were confused with other nontarget objects. For the color display, the relationships between mean search time (), peripheral visual acuity (θ) and rated discriminability (D), could be summarized as follows:

This is an encouraging finding. It leads one to hope that predictive procedures developed from these simple relationships can be applied in a wide range of complex search situations.