Perceptual Constancies: Part 2 -- Brightness Constancy

Brightness Constancy is the tendency for a visual object to be perceived as having the same brightness under widely different conditions of illumination. Brightness Constancy is based largely on prior knowledge and past experiences. The less experience had with an object, the less the effects of Brightness Constancy. A good example of Brightness Constancy is snow which can appear white under the light of the moon or under the light of the sun with provides much more brightness. It is useful in the way that it allows us to know the color of an object even under low levels of light.