Illusory contour
visual illusion that evokes the perception of an edge without a luminance or color change across that edge
An illusory contour or subjective contour is a visual illusion that evokes the perception of an edge without a luminance or color change across that edge. Illusory brightness and depth ordering often accompany illusory contours. Friedrich Schumann is often credited with the discovery of illusory contours around the beginning of the 20th century, but they are present in art dating to the Middle Ages. Gaetano Kanizsa's 1976 Scientific American paper marked the resurgence of interest in illusory contours for vision scientists.
Common types
Perhaps the most famous example of an illusory contour is the triangle configuration popularized by Gaetano Kanizsa. Kanizsa figures trigger the percept of an illusory contour by aligning circles with wedge-shaped portions removed in the visual field such that the edges form a shape. Although not explicitly part of the image, Kanizsa figures evoke the perception of a shape, defined by a sharp illusory contour. Typically, the shape seems brighter than the background, even though the luminance is in reality homogeneous. Additionally, the illusory shape seem to be closer to the viewer than the inducers. Kanizsa figures involve modal completion of the illusory shape and amodal completion of the inducers.
Begin with the source’s own compact description: “Illusory contour” is visual illusion that evokes the perception of an edge without a luminance or color change across that edge. The dossier treats that line as a proposition to test through Illusory, contour and visual, not as a finished interpretation.
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Named sources, stable identifiers and responsible institutions provide the strongest route from overview to verifiable evidence. The source revision retrieved here is dated Sep 13, 2026. The linked authority identifier is Q2629943. None of the 0 selected statements returned an explicit reference. The first chronological checks are 1976.
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This entry incorporates text from “Illusory contour” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.