A piece of paper looks white in both the noonday sun and under moonlight, even though there is less light being reflected off the paper under moonlight. This form of perceptual constancy is called _________.

A) size constancy
B) shape constancy
C) brightness constancy
D) color constancy

Brightness constancy refers to the ability of our perceptual system to recognize that an object's brightness remains constant, even in different lighting conditions. This is why a piece of paper looks white under both the noonday sun (bright illumination) and under moonlight (dim illumination), even though the actual amount of light being reflected off the paper is significantly different. Size constancy refers to the ability to perceive the true size of an object regardless of its distance from us, while shape constancy refers to our ability to perceive an object's shape as constant even when its orientation changes. Color constancy, on the other hand, refers to our ability to perceive the color of an object as constant even under different lighting conditions.