Local contour characteristics as determinants of pattern discrimination

Subjects were required to discriminate complex random polygons which had the same global shapes but differed in local contour characteristics. Discrimination was most often successful when local contour features comprised a few long line segments or when they were relatively complex. Local contour features of intermediate sized elements and intermediate complexity played a smaller role in discrimination. Presentation time and interstimulus interval effects, and their interaction were observed. A two-factor explanation was offered for the effect of the contour variable.