Perceived Size and Perceived Distance of a Growing Pattern on the Frontal Plane

Abstract

This experiment was conducted to examine perceived size (extent) and perceived distance of a two-point dot pattern whose inter-point separation was growing or shrinking. Eight subjects estimated size (extent) and distance under two amplitude conditions with different ranges of change in visual angle. Convergence distance were held constant (Conditions A and B), changed in the direction consistent with (Condition C) and paradoxical to the visual angle change (Condition D). The results showed that size estimation was influenced more strongly by the change in visual angle rather than the change in convergence distance and that the degree of size constancy was higher in the larger amplitude condition. The latter result suggested the importance of the continuity of motion and the effect of cognitive factor on perceived size and perceived distance. Causal inference by means of partial correlation was applied to the relations among visual angle, convergence distance, perceived size and perceived distance. We inferred the interaction of perceived size and perceived distance when convergence distance and visual angle were changed in paradoxical directions.