AP Psychology Practice Test 2026 - Free AP Psychology Practice Questions and Study Guide

Relative size is a depth cue that relies on the size of objects on the retina to inform the observer about their perceived distance. When two objects are of similar size, if one object casts a smaller retinal image than the other, it suggests that the smaller image is perceived as being further away. This is based on the understanding that objects which are farther from the observer appear smaller due to the perspective of the visual field. Thus, the correct answer accurately describes how our perception interprets size differences to deduce distance in relation to two similar-sized objects.

The other options presented pertain to different depth perception cues. Movement (involving relative motion) indicates the closeness of an object through motion parallax; the height in the visual field addresses surface placement; and brightness can imply light intensity but doesn't directly correlate to size perception in relation. Each of these cues operates under different principles than relative size does.