Perceptual Discriminability as a Basis for Selecting Graphic Symbols

Abstract

The purpose of this research was to develop a performance-based criterion for selecting among alternative symbols to be used in graphic displays. The specific criterion developed was an index of perceptual discriminability. Through regression analyses of an intersymbol similarity-rating matrix, it was concluded that symbols are judged more or less similar on the basis of the number of shared versus unique configural attributes (an X, a triangle, etc.), as opposed to primitive attributes (number of lines, arcs, etc.). An easy-to-use discriminability-index formula was derived from the regression analysis involving the configural attributes, and this formula was used to predict the results of an experiment involving a search for specific symbols embedded in an array. Indices obtained from a formula such as the one developed here could be used as part of the basis for choosing among alternative candidate symbols for inclusion in an existing symbol domain.