Difference between revisions of "Kanizsa triangle" - New World Encyclopedia

From New World Encyclopedia
({{Contracted}})
Line 5: Line 5:
  
 
[[Image:Kanizsa triangle.svg|thumb|right|225px|'''Kanizsa triangle''']]
 
[[Image:Kanizsa triangle.svg|thumb|right|225px|'''Kanizsa triangle''']]
The '''Kanizsa triangle''' is an [[optical illusion]] first described by the Italian psychologist [[Gaetano Kanizsa]] in 1955. <ref>{{Citation| last=Kanizsa | first=G| year=1955| title=Margini quasi-percettivi in campi con stimolazione omogenea. |journal=Rivista di Psicologia| volume=49|issue=1 |pages=7–30}}</ref> In the accompanying figure a white [[equilateral triangle]] is perceived, but in fact none is drawn. This effect is known as a ''subjective'' or ''illusory'' contour. Also, the nonexistent white triangle appears to be brighter than the surrounding area, but in fact it has the same brightness as the background.
+
The '''Kanizsa triangle''' is an [[optical illusion]] first described by the Italian psychologist [[Gaetano Kanizsa]] in 1955. The Kanizsa triangle is known as a ''subjective'' or ''illusory'' contour illusion. The Kanizsa triangle is similar to other contour illusions like the [[Ehrenstein illusion]].
  
Another contour illusion is the [[Ehrenstein illusion]].
+
==Discovery==
 +
The Kanizsa triangle is named for the Italian psychologist [[Gaetano Kanizsa]], who published his findings of the optical illusion in a 1955 edition of the Italian journal "Rivista di Psicologia".
 +
 
 +
==Description==
 +
When looking at the Kanizsa triangle, one sees the shape of a white, equilateral triangle in the center that appears to occlude the shapes around it. The nonexistent white triangle also appears to be brighter than the surrounding area, but in fact it has the same brightness as the background.
 +
 
 +
==Explanation==
 +
The "phantom edge phenomena" (seeing an outline that is not actually there) is due to what neuropsychologists call the "T-effect". Groups of neural cells see breaks in lines or shapes, and if given no further input, will assume that there is a figure in front of the lines. Scientists believe that this happens because the brain has been trained to view the break in lines as an object that could pose a potential threat. With lack of additional information, the brain errs on the side of safety and perceives the space as an object. The circle is the most simple and symmetrical object, so the mind usually sees a circle unless active effort is made to see an alternate shape.<ref>[http://www.blelb.ch/english/blelbspots/spot06/exspot06_en.htm#top "The Grid illusion of Spot 06"] The Visual Perception Lab. Retrieved October 10, 2007.</ref>
 +
 
 +
==Applications==
 +
Like many other visual and perceptual illusions, the Kanizsa triangle helps neuropsychologists study the various ways the brain and eyes perceive visual information.  
  
 
==Notes==
 
==Notes==
Line 13: Line 23:
  
 
==References==
 
==References==
 
+
*Hoffman, Donald David and Donald D. Hoffman. ''Visual Intelligence: How We Create What We See'' February 2000. W. W. Norton & Company ISBN 0393319679
 +
*Koch, Christof. ''The Quest for Consciousness: A Neurobiological Approach'' March 2004. Roberts & Company Publishers. ISBN 0974707708
 +
*Norretranders, Tor. ''The User Illusion: Cutting Consciousness Down to Size'' August 1999. Penguin. ISBN 0140230122
  
  

Revision as of 19:30, 10 October 2007


Kanizsa triangle

The Kanizsa triangle is an optical illusion first described by the Italian psychologist Gaetano Kanizsa in 1955. The Kanizsa triangle is known as a subjective or illusory contour illusion. The Kanizsa triangle is similar to other contour illusions like the Ehrenstein illusion.

Discovery

The Kanizsa triangle is named for the Italian psychologist Gaetano Kanizsa, who published his findings of the optical illusion in a 1955 edition of the Italian journal "Rivista di Psicologia".

Description

When looking at the Kanizsa triangle, one sees the shape of a white, equilateral triangle in the center that appears to occlude the shapes around it. The nonexistent white triangle also appears to be brighter than the surrounding area, but in fact it has the same brightness as the background.

Explanation

The "phantom edge phenomena" (seeing an outline that is not actually there) is due to what neuropsychologists call the "T-effect". Groups of neural cells see breaks in lines or shapes, and if given no further input, will assume that there is a figure in front of the lines. Scientists believe that this happens because the brain has been trained to view the break in lines as an object that could pose a potential threat. With lack of additional information, the brain errs on the side of safety and perceives the space as an object. The circle is the most simple and symmetrical object, so the mind usually sees a circle unless active effort is made to see an alternate shape.[1]

Applications

Like many other visual and perceptual illusions, the Kanizsa triangle helps neuropsychologists study the various ways the brain and eyes perceive visual information.

Notes

  1. "The Grid illusion of Spot 06" The Visual Perception Lab. Retrieved October 10, 2007.

References
ISBN links support NWE through referral fees

  • Hoffman, Donald David and Donald D. Hoffman. Visual Intelligence: How We Create What We See February 2000. W. W. Norton & Company ISBN 0393319679
  • Koch, Christof. The Quest for Consciousness: A Neurobiological Approach March 2004. Roberts & Company Publishers. ISBN 0974707708
  • Norretranders, Tor. The User Illusion: Cutting Consciousness Down to Size August 1999. Penguin. ISBN 0140230122


Credits

New World Encyclopedia writers and editors rewrote and completed the Wikipedia article in accordance with New World Encyclopedia standards. This article abides by terms of the Creative Commons CC-by-sa 3.0 License (CC-by-sa), which may be used and disseminated with proper attribution. Credit is due under the terms of this license that can reference both the New World Encyclopedia contributors and the selfless volunteer contributors of the Wikimedia Foundation. To cite this article click here for a list of acceptable citing formats.The history of earlier contributions by wikipedians is accessible to researchers here:

The history of this article since it was imported to New World Encyclopedia:

Note: Some restrictions may apply to use of individual images which are separately licensed.