Light

Constancy

Definition

Constancy refers to the tendency of our perception to remain unchanged even when the stimuli changes. Size constancy is perceiving objects as having a constant size, even while our distance from them varies. Shape constancy is understanding that an object's shape remains the same despite changes in its perceived shape due to rotation or other factors. Brightness constancy means we perceive an object as having a constant brightness even if its illumination changes.

Analogy

Think of constancies like your favorite song on different speakers - it might sound slightly different on your phone speaker versus a high-quality stereo system (like how objects can look different under varying light conditions or distances), but you still recognize it as the same song (just like you recognize an object's true size, shape, and brightness).

Related terms

Perception: The process by which sensory information is interpreted and consciously experienced.

Depth Perception: The ability to perceive spatial relationships, especially distances between objects, in three dimensions.

Color Constancy: Perceiving familiar objects as having consistent color, even if changing illumination alters the wavelengths reflected by the object.