aftereffect

   Also known as aftersensation and perceptual aftereffect. All three terms refer to the illusory visual perception that may follow prolonged exposure to a particular visual stimulus. As a rule, aftereffects present themselves in the inverted shape of the original percept. Thus in a subgroup of aftereffects, called the * tilt aftereffect, staring at a pattern of lines tilted to the right is followed by the illusory impression that vertical lines are tilted to the left. Other examples of aftereffects include the * contingent aftereffect (such as the *McCollough effect, characterized by the complex, orientation-contingent illusion of complementary colours), the *motion aftereffect (such as the * waterfall illusion, in which stationary objects are perceived as if moving upwards after the prolonged viewing of descending masses of water), the * postural aftereffect, the group of * kinaesthetic aftereffects, the size aftereffect, the * spiral aftereffect, and the * rotational aftereffect. Most of the research on aftereffects involves visual illusory phenomena, but aftereffects can also occur in other (and perhaps all) sensory modalities. As to their neurophysiological correlates, various complex hypotheses have been developed, many of which involve the adaptation of single cells or cell columns within the cerebral sensory cortex. Aftereffects are commonly classified as * physiological illusions.

   References

   Mather, G., Verstraten, F., Anstis, S. (1998). The motion aftereffect: A modern perspective. Cambridge, MA: MIT Press.