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

Lightness constancy illustrates the principle that objects maintain the same perceived lightness regardless of changes in illumination. This phenomenon allows us to recognize that a white piece of paper, for instance, appears white both in bright sunlight and in dim indoor lighting, even though the amount of light reflecting off the paper differs significantly due to different lighting conditions.

This ability to perceive an object's lightness as stable is crucial for visual perception, as it helps us accurately interpret our environment. It reflects how our brains interpret visual information, integrating factors like the surrounding light and colors, to maintain a consistent perception of an object's characteristics, which enhances our ability to navigate and recognize objects in varying conditions.

The other options do not encapsulate the essence of lightness constancy. While shadows can influence color perception and screen brightness adjustments relate to ambient lighting conditions, they do not address the core idea of perceived lightness remaining constant under varying lights, which is central to the concept of lightness constancy.