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Directional organization and shape formation: new illusions and Helmholtz’s square

Pinna, Baingio (2015) Directional organization and shape formation: new illusions and Helmholtz’s square. Frontiers in human neuroscience , in press. eISSN 1662-5161. Article.

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DOI: 10.3389/fnhum.2015.00092

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According to Helmholtz’s Square illusion, a square appears wider when it is filled with vertical lines and higher when filled with horizontal lines (Helmholtz, 1866). Recently, Pinna (2010a) demonstrated that the grouping of small squares on the basis of the similarity principle influences also perception of their shape and of the whole emerging shapes. The direction imparted by grouping is the main attribute that influences the shape by polarizing it in the same direction both globally and locally. The rectangle illusion is opposite to what expected on the basis of Helmholtz’s Square illusion. Aim of this work is to solve the antinomy between the two sets of illusions and to demonstrate a common explanation based on the interaction between different sources of directional organization. This was accomplished by introducing some new phenomena and through phenomenological experiments proving the role played by the directional shape organization in shape formation. According to our results, Helmholtz’s square illusion shows at least two synergistic sources of directional organization: the direction of the grouping of the lines due to their similarity of the luminance contrast and the direction of the grouping of the lines due to the good continuation.

Item Type:Article
ID Code:10782
Status:In Press
Uncontrolled Keywords:Shape perception1, Gestalt psychology2, perceptual organization3, visual illusions4, directional organization5
Subjects:Area 11 - Scienze storiche, filosofiche, pedagogiche e psicologiche > M-PSI/01 Psicologia generale
Divisions:001 Università di Sassari > 01-a Nuovi Dipartimenti dal 2012 > Architettura, Design e Urbanistica
Publisher:Frontiers Research Foundation
Copyright Holders:© 2015 Pinna
Additional Information:This Provisional PDF corresponds to the article as it appeared upon acceptance, after rigorous peer-review. Fully formatted PDF and full text (HTML) versions will be made available soon.
Deposited On:10 Feb 2015 11:41

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