Perceptual Constancy
This video presents the same text shown beside it, spoken and on screen. It adds nothing the text does not say.
State
Perceptual constancy is the perception of an object's size, shape, and brightness as stable despite changing sensory input.
Show
A door swinging open projects a changing trapezoid on the retina and is seen throughout as a rectangle.
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Constancy is an achievement, not a default. It requires cues that can be removed.