The effects of perspective alterations on apparent size and distance scales

Abstract

Ss made magnitude estimations first of the areas, then of the distances, of four circles presented at five distances within an enclosed box 9 ft long. There were three viewing situations: the box had parallel walls, converging walls, or diverging walls. The variations in perspective cues influenced the apparent distance scales: with converging and parallel walls, apparent distance grew as the 1.4 power of physical distance; with diverging walls, it grew as the .95 power. Apparent area was related to distance differently in the three conditions: with converging walls, apparent area increased with distance; with parallel and diverging walls, apparent area decreased with distance. Apparent area was thus not related to changes in physical distance as the apparent distance effects would predict. In each condition, the ratio of apparent area to apparent distance (S′/D′) was a monotonie increasing function of retinal angle θ, but the rate of growth varied among the three conditions. The failure of θ D′ to define a unique value of S′ across conditions indicates that the size-distance invariance hypothesis is inadequate to predict the outcome of this experiment.