Angle illusion on a picture's surface.
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.
University of Toronto at Scarborough, 1265 Military Trail, Toronto ON M1C1A4, Canada.
Sherief
S
Hammad
John M
JM
Kennedy
Igor
I
Juricevic
Shazma
S
Rajani
D000328:Adult; D005260:Female; D005556:Form Perception / Q000502:physiology*; D006801:Humans; D007088:Illusions / Q000502:physiology*; D008297:Male; D010151:Paintings; D010364:Pattern Recognition, Visual / Q000502:physiology*