Difference between revisions of "White's illusion" - New World Encyclopedia

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[[Category:Politics and social sciences]]
 
[[Category:Politics and social sciences]]
 
[[Category:Psychology]]
 
[[Category:Psychology]]
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[[Category:Illusion]]
  
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[[Image:Whites illusion.svg|thumb|225px|White's illusion]]
  
[[Image:White_illusion.png|frame|225px|White's illusion]]
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'''White's illusion''' is an [[optical illusion]] illustrating the fact that the same target [[luminance]] can elicit different perceptions of [[brightness]] in different contexts. White's illusion is sometimes combined with the [[Munker illusion]] (a similar illusion that uses colors instead of grayscale) and referred to as the "Munker-White" illusion. White's illusion, as well as numerous other visual and perceptual [[illusion]]s, provide a valuable way to investigate how the eye and brain process visual information. Equally, they are used by [[art]]ists for visual effect, entertaining and satisfying the endless fascination [[human being]]s have with novelty and [[creativity]].
  
'''White's illusion''' is an [[optical illusion]] illustrating the fact that the same target [[luminance]] can elicit different perceptions of [[brightness]] in different contexts.
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==Discovery==
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''White's illusion'' was discovered in 1979 by M. White, who published his findings in the psychological journal ''Perception'' in 1979 and 1981.  
  
Note, that although the gray rectangles are all of equal [[luminance]], the ones seen in the context with the dark stripes appear brighter than the ones seen in the context with the bright stripes. Note that this effect is opposite to what would be expected from a simple physiological explanation on the basis of [[simultaneous contrast]] (in that case the rectangles sharing the long borders with the dark stripes should appear brighter).
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==Description==
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White's illusion is made up of a series of black and white horizontal bars. On one side, shorter gray bars cover the black bars; on the other side, they cover the white bars. When observing the image, it appears as though the gray bars surrounded by white stripes are definitively lighter than the gray bars surrounded by black stripes. In addition to appearing lighter, the gray bars surrounded by white also appear to be brighter, or of higher [[luminance]].
  
[[Television]] screens depend on this visual illusion. [[Pixel]]s that are not illuminated are seen as black, when they are really the same dim gray seen when the television is turned off. An even more extreme example is an [[overhead projector]] screen, which is bright white in reality but whose less-illuminated regions appear black. Note that this is an effect of [[simultaneous contrast]], not White's illusion, per se.
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==Explanation==
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The effect of the White illusion is opposite to what would be expected from a simple physiological explanation on the basis of [[simultaneous contrast]] (the rectangles sharing the long borders with the dark stripes should appear brighter, not darker). While the effect is not fully understood, theories have been advanced to explain the mechanism that causes the White illusion.  
  
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Some theories stay within the framework of simultaneous contrast, but propose that the reactions of different parts of the visual system are responsible for the illusion. Other theories propose that the processing of the T-junctions (the area where the gray stripes intersect adjacent stripes) create the illusion.<ref>Barton L. Anderson. 2003. [http://www2.psy.unsw.edu.au/Users/BAnderson/TexturedWhites.pdf "Perceptual organization and White's illusion"] ''Perception'', 2003. Vol 32. pp. 269-284. Retrieved January 3, 2008.</ref>
  
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==Applications==
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The fact that White's illusion behaves in opposition to what would be expected by physiological mechanisms such as simultaneous contrast and [[lateral inhibition]] has sparked scientists and researchers into an attempt to discover the actual mechanism that causes the effect. The fact that this illusion contradicts previous assumptions about the visual system may help scientists to come to a better understanding of the mechanisms involved in vision and [[perception]].
  
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==Notes==
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<references/>
  
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==References==
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*Hoffman, Donald D. ''Visual Intelligence: How We Create What We See''. 2000. W. W. Norton. ISBN 0393319679
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*Ninio, Jacques. ''The Science of Illusions''. 2001. Cornell University Press. ISBN 0801437709
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*Seckel, Al. ''The Art of Optical Illusions''. 2000. Carlton Books. ISBN 1842220543
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*White M. 1979. "A new effect of pattern on perceived lightness." ''Perception'', 8, 413-416.
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*White M. 1981. "The effect of the nature of the surround on the perceived lightness of gray bars within square-wave test gratings." ''Perception'', 10, 215-230.
  
 
{{Credits|White's_illusion|83147402}}
 
{{Credits|White's_illusion|83147402}}

Revision as of 20:55, 21 November 2022


White's illusion

White's illusion is an optical illusion illustrating the fact that the same target luminance can elicit different perceptions of brightness in different contexts. White's illusion is sometimes combined with the Munker illusion (a similar illusion that uses colors instead of grayscale) and referred to as the "Munker-White" illusion. White's illusion, as well as numerous other visual and perceptual illusions, provide a valuable way to investigate how the eye and brain process visual information. Equally, they are used by artists for visual effect, entertaining and satisfying the endless fascination human beings have with novelty and creativity.

Discovery

White's illusion was discovered in 1979 by M. White, who published his findings in the psychological journal Perception in 1979 and 1981.

Description

White's illusion is made up of a series of black and white horizontal bars. On one side, shorter gray bars cover the black bars; on the other side, they cover the white bars. When observing the image, it appears as though the gray bars surrounded by white stripes are definitively lighter than the gray bars surrounded by black stripes. In addition to appearing lighter, the gray bars surrounded by white also appear to be brighter, or of higher luminance.

Explanation

The effect of the White illusion is opposite to what would be expected from a simple physiological explanation on the basis of simultaneous contrast (the rectangles sharing the long borders with the dark stripes should appear brighter, not darker). While the effect is not fully understood, theories have been advanced to explain the mechanism that causes the White illusion.

Some theories stay within the framework of simultaneous contrast, but propose that the reactions of different parts of the visual system are responsible for the illusion. Other theories propose that the processing of the T-junctions (the area where the gray stripes intersect adjacent stripes) create the illusion.[1]

Applications

The fact that White's illusion behaves in opposition to what would be expected by physiological mechanisms such as simultaneous contrast and lateral inhibition has sparked scientists and researchers into an attempt to discover the actual mechanism that causes the effect. The fact that this illusion contradicts previous assumptions about the visual system may help scientists to come to a better understanding of the mechanisms involved in vision and perception.

Notes

  1. Barton L. Anderson. 2003. "Perceptual organization and White's illusion" Perception, 2003. Vol 32. pp. 269-284. Retrieved January 3, 2008.

References
ISBN links support NWE through referral fees

  • Hoffman, Donald D. Visual Intelligence: How We Create What We See. 2000. W. W. Norton. ISBN 0393319679
  • Ninio, Jacques. The Science of Illusions. 2001. Cornell University Press. ISBN 0801437709
  • Seckel, Al. The Art of Optical Illusions. 2000. Carlton Books. ISBN 1842220543
  • White M. 1979. "A new effect of pattern on perceived lightness." Perception, 8, 413-416.
  • White M. 1981. "The effect of the nature of the surround on the perceived lightness of gray bars within square-wave test gratings." Perception, 10, 215-230.

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