Morgan M, Dillenburger B. Geometrical features underlying the perception of collinearity.
Vision Res 2016;
128:83-94. [PMID:
27664353 DOI:
10.1016/j.visres.2016.09.008]
[Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Revised: 09/10/2016] [Accepted: 09/16/2016] [Indexed: 11/25/2022]
Abstract
The magnitude of the Poggendorff bias in perceived collinearity was measured with a 2AFC task and roving pedestal, and was found to be in the region of 6-8deg, within the range of previous estimates. Further measurements dissected the bias into several components: (1) The small (∼1deg) repulsion of the orientation of the pointer from the parallel, probably localized in the part of the line near the intersection (2) A small (<1deg) location bias affecting the intersection of pointers and inducing lines; and (3) A larger (>1deg) bias in the orientation of virtual lines crossing the gap between two parallels, towards the orientation of the parallels, or equivalently (4) An orthogonal bias in actively constructing a virtual line across the gap. We conclude that orientation repulsion by itself is an inadequate explanation of the Poggendorff effect, and that a full explanation must take account of the way in which observers construct virtual lines in visual space in order to carry out elementary geometrical tasks such as extrapolation.
Collapse