Contingent Aftereffect

A contingent aftereffect is an illusory perception that appears on a test stimulus only after a person has been exposed for an extended period to an induction stimulus that pairs one stimulus feature with another, such as a color paired with an orientation or a direction of motion. It differs from a simple aftereffect because a distinct test stimulus is needed before the illusion becomes visible at all, and researchers have documented contingent aftereffects across the visual, auditory and haptic senses, not only vision. The best known example of the class is the McCollough effect, in which black and white gratings of one orientation come to look faintly tinted with a color after a person has viewed colored gratings of two different orientations, with the tint tied specifically to orientation rather than to the whole visual field. This description is adapted from Wikipedia contributors under CC BY-SA 4.0; changes were made. https://creativecommons.org/licenses/by-sa/4.0/