Guidi S, Parlangeli O, Bettella S, Roncato S, 2011, "Features of the selectivity for contrast polarity in contour integration revealed by a novel tilt illusion" Perception 40(11) 1357 – 1375
Download citation data in RIS format
Features of the selectivity for contrast polarity in contour integration revealed by a novel tilt illusion
Stefano Guidi, Oronzo Parlangeli, Sandro Bettella, Sergio Roncato
Received 20 December 2010, in revised form 12 October 2011; published online 14 December 2011
Abstract. We studied a novel illusion of tilt inside checkerboards due to the role of contrast polarity in contour integration. The preference for binding of oriented contours having same contrast polarity, over binding of opposite polarity ones (CP rule), has been used to explain several visual illusions. In three experiments we investigated how the binding effect is influenced by luminance contrast value, relatability of contour elements, and distance among them. Experiment 1 showed that the effect was indeed present only when the CP rule was satisfied, and found it to be stronger when the luminance contrast values of the elements are more similar. In experiment 2 the illusion was reported only with relatable edges, and its strength was modulated by the degree of relatability. The CP-rule effectiveness, thus, seems to depend on good continuation. The intensity of contrast polarity signals propagating from an oriented contour might be the less intense, the more its direction deviates from linearity. In experiment 3 we estimated the distance threshold and found it to be smaller than the one found for other illusions, arising with collinear fragments. This seems to show that the reach of the contrast polarity signal inside the association field of a contour unit is shorter along non-collinear orientations than along collinear ones.
Full-text PDF size: 965 Kb
References 35 references, 28 with DOI links ()
Your computer (IP address: 18.104.22.168) has not been recognised as being on a network authorised to view the full text or references of this article. If you are a member of a university library that has a subscription to the journal, please contact your serials librarian (subscriptions information).