Apiece 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 constancy.

Brightness consistency

There are three types of perceptual consistency
Types of Perceptual Constancy: Shape, Size, and Brightness Size constancy
Since the moon and sun affect light, brightness consistency is occurring.
Brightness constancy is our visual ability to perceive objects as having the same level of brightness even though the level of lighting changes.