Second-order texture gratings produce overestimation of height in depictions of rectangles and steps


The horizontal-vertical illusion (HVI) has been proposed as a method to increase the perceived height of steps, increase toe clearance and prevent falls. High contrast vertical stripes are placed on the step riser abutting a horizontal edge-highlighter creating ‘T’ junctions which are thought to promote the illusion. Various configurations of the HVI were tested including luminance gratings (L) and second-order modulations of contrast (CM), spatial frequency (FM) and orientation (OM). Observers were asked to compare the apparent height of gratings with that of either filled, unmodulated rectangles or unfilled rectangles. Rectangles were presented alone or as part of a step with a highlighter. In some conditions highlighters matched the properties of the grating; in others or not. In one critical experiment, the HVI was compared for steps with highlighters that were separated from the riser by a thin line and those where the risers and highlighters were continuous. All gratings except FM appeared taller when presented in the step configuration with a continuous, matching highlighter. This effect was greatly reduced when a thin line separated the grating from the highlighter and abolished for mis-matched highlighters and risers. In the rectangle conditions, all cues appeared taller than blank rectangles and L and CM appeared taller than filled-unmodulated rectangles. In conclusion, second-order cues may be useful for inducing the HVI onto steps. However, the ability of vertical stripes and edge-highlighters to accentuate perceived step height may be due to aggregation of the highlighter into the grating rather than the normal horizontal-vertical illusion.

Publication DOI:
Divisions: College of Health & Life Sciences > School of Psychology
College of Health & Life Sciences > Aston Institute of Health & Neurodevelopment (AIHN)
College of Health & Life Sciences
Additional Information: © Published by Elsevier Ltd. This is an open access article under the CC BY license
Uncontrolled Keywords: Horizontal vertical illusion,Second order,Texture,Step Height
Publication ISSN: 1878-5646
Last Modified: 04 Jul 2024 07:09
Date Deposited: 03 Aug 2022 13:25
Full Text Link:
Related URLs: https://www.sci ... 79?via%3Dihub#! (Publisher URL)
PURE Output Type: Article
Published Date: 2022-11
Published Online Date: 2022-07-28
Accepted Date: 2022-06-27
Authors: Schofield, Andrew J (ORCID Profile 0000-0002-0589-4678)



Version: Published Version

License: Creative Commons Attribution

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