title: 3-D processing in the Poggendorff illusion.
abstract: In the Poggendorff illusion two collinear oblique lines, separated by two vertical lines, appear to be misaligned. 3-D processing of the oblique but not the vertical lines is considered to cause this apparent misalignment. We investigated whether more explicitly triggering 2-D versus 3-D interpretations of the different parts of Poggendorff-like displays would influence the apparent misalignment. In Experiment 1, we found that compared to 2-D controls, 3-D interpretations of the vertical parts did not influence apparent misalignment, while for the oblique parts 3-D processing resulted in more apparent misalignment than 2-D controls. In Experiment 2, the amount of contour convergence of the oblique parts was manipulated resulting in the 3-D blocks, but not the 2-D line patterns, to be perceived as receding in depth. Now, apparent misalignment increased the more the 3-D blocks were perceived as receding in depth. We conclude that apparent misalignment in Poggendorff-like displays can be influenced by different interpretations of its separate parts, while keeping the local junctions between the different elements the same.
authors.affiliation: Nijmegen Institute for Cognition and Information, Radboud University Nijmegen, The Netherlands. arno.koning@psy.kuleuven.be
authors.forename: Arno
authors.initials: A
authors.lastname: Koning
authors.forename: Rob
authors.initials: R
authors.lastname: van Lier
mesh_terms: D006801:Humans; D021621:Imaging, Three-Dimensional; D009903:Optical Illusions; D014796:Visual Perception