- waterfall illusion
- Also known as waterfall effect and waterfall phenomenon. All three terms refer to a variant of the * motion aftereffect characterized by an optical *illusion of upward motion in stationary objects. The term waterfall illusion was coined in or shortly before 1880 by the British physicist Sil-vanus Phillips Thompson (1851-1916). Theintro-duction of the term waterfall effect has been attributed to the British psychologist Richard Langton Gregory (b. 1923) and the introduction of the term waterfall phenomenon to the American optometrists Horace B. Barlow (b. 1921) and Richard M. Hill. The Greek philosopher Aristotle (384-322 BC) has been credited with being the first author to describe the phenomenon, referring to it as * river illusion. The first modern description of the waterfall illusion can be found in a paper published in 1834 by the chemist and natural philosopher Robert Addams. Addams reported the phenomenon after having observed it at the Falls of Foyers, on the borders of Loch Ness, Scotland. The waterfall illusion can be induced by looking for some time at a descending mass of water and then shifting one's gaze to the stationary objects in the environment. These stationary objects then appear to be moving in the opposite direction. The waterfall illusion is commonly classified as a * physiological illusion. Physiologically, the waterfall illusion and other motion aftereffects have been associated with a process called neural adaptation, i.e. a selective response of neurons in the visual association cor-textomovementinthe visual field.Amove-ment aftereffect that has been classified by some as a special variant of the waterfall illusion is known as * Archimedes's spiral. The waterfall illusion should not be confused with the *hygric hallucination.ReferencesAddams, R. (1834). An account of a peculiar optical phaenomenon seen after having looked at a moving body, &c. London and Edinburgh Philosophical Magazine and Journal of Science, 5, 373-374.Barlow, H.B., Hill, R.M. (1963). Evidence for a physiological explanation of the waterfall phenomenon and figural aftereffects. Nature, 200, 1434-1435. Gregory, R.L. (1981). Eye andbrain. Third revised edition. New York, NY: McGraw-Hill. Mather, G., Verstraten, F., Anstis, S. (1998). The motion aftereffect: A modern perspective. Cambridge, MA: MIT Press.Thompson, P. (1880). Optical illusions ofmotion. Brain, 3, 289-298.
Dictionary of Hallucinations. J.D. Blom. 2010.
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waterfall effect — see waterfall illusion … Dictionary of Hallucinations
waterfall phenomenon — see waterfall illusion … Dictionary of Hallucinations
Waterfall (M. C. Escher) — Artwork title=Waterfall artist=M. C. Escher year=1961 type=lithograph height=38 width=30 Waterfall is a lithograph print by the Dutch artist M. C. Escher which was first printed in October, 1961. It shows an apparent paradox where water from the… … Wikipedia
river illusion — A term attributed to the Greek philosopher Aristotle (384 322 BC), who reportedly used it as an equivalent of what is known today as waterfall illusion. For a more detailed account, see the entry Waterfall illusion. References Thompson,… … Dictionary of Hallucinations
Aristotle's illusion — The eponym Aristotle s illusion refers to the Greek philosopher Aristotle (384 322 BC), who appears to have been the first to describe the concomitant phenomenon in his books On dreams, Metaphysics,andProblems. The expression Aristotle s… … Dictionary of Hallucinations
Optical illusion — This article is about visual perception. For the Time Requiem album, see Optical Illusion (album). An optical illusion. The square A is exactly the same shade of gray as square B. See checker shadow illusion. An optical illusion (also called a… … Wikipedia
Motion aftereffect — The motion after effect (MAE) is a visual illusion experienced after viewing a moving visual stimulus for a time (seconds to minutes) with stationary eyes, and then fixating a stationary stimulus. The stationary stimulus appears to move in the… … Wikipedia
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… … Dictionary of Hallucinations
spiral motion aftereffect — (spiral MAE) Also known as spiral aftereffect. Both terms are used to denote a * motion aftereffect that can be induced with the aid of an * Archimedes s spiral or * Plateau s spiral. After viewing such a rotating spiral for several minutes… … Dictionary of Hallucinations
Archimedes' spiral — Also known as Plateau s spiral. The eponym Archimedes spiral refers to the Greek mathematician and physicist Archimedes of Syracuse (297 212 BC). The eponym Plateau s spiral refers to the Belgian physicist Joseph Plateau (18011883). Both… … Dictionary of Hallucinations