title: Is amodal completion necessary for the formation of illusory figures?
abstract: Kanizsa's hypothesis suggests that the creation of an anomalous surface is due to the amodal completion of the inducers. In the present paper a new pattern that is able to disconfirm this explanation is presented. According to the Helmholtz-Ratoosh law amodal completion only occurs when the borders of two adjacent surfaces meet forming T-shaped junctions. When the borders of the two adjacent surfaces have Y-shaped junctions, amodal completion is absent. However, when a pattern inducing an anomalous figure has the latter figural characteristics, in spite of the absence of amodal completion, an illusory figure is still visible. In this paper a set of experimental results (carried out by means of a magnitude estimation procedure as well as the method of constant stimuli) supporting the aforementioned observations is presented.
authors.affiliation: Dipartimento di Psicologia, Università di Roma La Sapienza, Italy.
authors.forename: F
authors.initials: F
authors.lastname: Purghé
mesh_terms: D000328:Adult; D001288:Attention; D005260:Female; D006801:Humans; D008297:Male; D009903:Optical Illusions; D009949:Orientation; D010364:Pattern Recognition, Visual; D010466:Perceptual Closure; D011601:Psychophysics