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Published on: April 16, 2014
Angle illusion on a picture's surface
Sherief Hammad1, John M Kennedy, Igor Juricevic
1University of Toronto at Scarborough, 1265 Military Trail, Toronto ON M1C1A4, Canada.
Abstract:
Shapes on picture surfaces are not seen accurately (Arnheim, 1954). In particular, if they depict 3-D forms, angles between lines on a picture surface are misperceived. To test four theories of the misperception, subjects estimated acute and obtuse internal angles of quadrilaterals. Each quadrilateral was shown alone or as part of a drawing of a cube. The drawings showed the tops of the cubes, tilted at various angles around a horizontal axis. This generated different acute and obtuse angles in the drawings. Compared to a quadrilateral on its own, judgments of the acute and obtuse angles in the cube drawings were biased towards 90 degrees . The bias was present over a wide range of intermediate tilts. The results support a perspective convergence theory and run counter to 'Extreme Foreshortening', Gestalt and Cognitive theories.
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