Emergent Properties of Visual Patterns at Sizes well above Threshold

Abstract

Discrimination performance of two classes of patterns (histoforms and polygons) was determined as a function of the size of the forms at three levels of complexity (4, 6, and 8 columns or angles). The visual angle subtense of the stimulus forms was varied over a range of sizes from near threshold (1.88 min.) to well above it (16.56 min.). The important finding is that below a visual angle of 8 min. discrimination of the form is essentially identical in terms of both accuracy and speed of identification. At angular sizes above 8 min. consistent differences in the rate of processing the two classes of forms emerged. The results were interpreted as indicating that identification performance depends on “emergent features” of the forms as they increase in size.