title: Assessment of apparent length and angle explanations of the Poggendorff effect.
abstract: Explanations of the Poggendorff effect were assessed by comparing the degree of angular distortion induced by modified and traditional configurations. Assimilation theory predicted that the traditional effect would be reversed in modified configurations. Analysis showed that the effect, although reduced in magnitude, was not reversed. Comparison of the degree of the effect induced by modified and traditional configurations indicated that a substantial portion of the Poggendorff effect was due to processing of areas between the long vertical lines of the display. This finding is not consistent with theories based on subjective distortion of angles. It was concluded that a theory of the Poggendorff effect must include processing of internal areas of the configuration.
mesh_terms: D000328:Adult; D004193:Discrimination Learning; D005260:Female; D005556:Form Perception; D006801:Humans; D007088:Illusions; D008297:Male; D009903:Optical Illusions; D009949:Orientation