Ehrenstein illusion
The Ehrenstein illusion is an optical illusion in which a circle appears at the end points of a series of lines. The Ehrenstein illusion is one of the most popular subjective contor illusions (illusions that create the impression of a shape even though a large portion of the contour is nonexistant.) A similar effect can be found in the Kanizsa triangle.
Discovery
The Ehrenstein illusion is named for German psychologist Walter Ehrenstein, who published his findings in 1941 in the German psychology journal 'Zeitschrift für Psychologie' (150, 83-91). Ehrenstein published his findings as a modification of the Hermann grid illusion.
Description
The classic Ehrenstein illusion consists of a grid in which the lines at an intersection terminate a short distance away from the intersection. When looking at the illusion, the viewer tends to see a circle that is slightly brighter than the background. If the space at the intersetctions is imagined to be square, it can also be perceived that way.
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, 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 percieves 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 perceptual illusions, the Ehrenstein illusion helps neuroscientists study how the brain processes visual information.
Notes
- ↑ "The Grid illusion of Spot 06" The Visual Perception Lab. Retrieved October 4, 2007.
ReferencesISBN links support NWE through referral fees
- Ninio, Jacques. "The Science of Illusions" April 2001. Cornell University Press. ISBN 0801437709
- Seckel, Al. "More Optical Illusions" October 2002. Carlton Books ISBN 1842224875
- Zakia, Richard D. "Perception and Imaging" December 2001. Focal Press. ISBN 024080466X
