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Updated: Jun 19, 2026

Methods to Explore the Influence of Top-down Visual Processes on Motor Behavior
Published on: April 16, 2014
Influence of parallel and orthogonal real lines on illusory contour perception
Barbara Dillenburger1, Anna W Roe
1Institute of Imaging Science, Department of Psychology, Vanderbilt University, Medical Center North, 1161 21st Ave. S., Nashville, TN 37232-2310, USA. barbara.dillenburger@vanderbilt.edu
Abstract:
Real lines and illusory contours (ICs) have been reported to either interfere with or facilitate the perception of the other, depending on real line orientation and contrast. Here we investigate contextual effects of real lines on illusory contour perception. Curvature discrimination thresholds of Kanizsa-contours were measured for superimposed real lines of different sub- and suprathreshold contrasts. We find that parallel lines interfere with curvature discrimination at suprathreshold, whereas orthogonal lines interfere at subthreshold contrasts. We did not find stable facilitating effects of lines in any orientation or contrast. These results are discussed in relation to existing physiological and imaging data.
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