Three-dimensional shape from shading is modulated by top-down attention: Evidence from event-related potentials

Matthews, Joshua P., Mills, Debra L. and Sapir, Ayelet (2025) Three-dimensional shape from shading is modulated by top-down attention: Evidence from event-related potentials. i-Perception, 16 (4). ISSN 2041-6695

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Abstract

Shading is an important monocular cue for three-dimensional (3D) perception, whereby 3D shape can be inferred from shading patterns across an object, in a process termed shape-from-shading. Shape-from-shading has been characterised as a pre-attentive process that occurs in parallel across the visual field. Recent evidence, however, has challenged this notion, suggesting that it consists of an early pre-attentive process and a later stage of processing that is reliant on top-down attention. Here, we use event-related potentials (ERPs) to test this claim whilst participants were instructed either to ignore or to attend to shaded stimuli that could be perceived as two-dimensional (2D) and 3D. We found that 3D stimuli evoked a larger N1 component than 2D stimuli in both attended and unattended conditions, implying an early, pre-attentive processing stage in shape-from-shading. This activity was lateralised to the right hemisphere when participants attended to the stimuli, in accordance with the right hemisphere advantage in top-down attention. Further, when participants attended to the stimuli, a larger N2 component for 3D compared to 2D shape was found, suggesting a late, top-down process for identifying 3D shape. These findings provide evidence for two distinct stages of processing for shape-from-shading and suggest that attention is necessary for the perception of shape-from-shading.

Item Type:	Article
Additional Information:	Publisher Copyright: © The Author(s) 2025. This article is distributed under the terms of the Creative Commons Attribution 4.0 License (https://creativecommons.org/licenses/by/4.0/) which permits any use, reproduction and distribution of the work without further permission provided the original work is attributed as specified on the SAGE and Open Access page (https://us.sagepub.com/en-us/nam/open-access-at-sage).
Uncontrolled Keywords:	depth perception,event-related potentials,lateralisation,shape from shading,three-dimensional shape,top-down attention,experimental and cognitive psychology,ophthalmology,sensory systems,artificial intelligence ,/dk/atira/pure/subjectarea/asjc/3200/3205
Faculty \ School:	Faculty of Social Sciences > School of Psychology
Related URLs:	http://www.scopus.com/inward/record.url?... https://research.bangor.ac.uk/en/publica...
Depositing User:	LivePure Connector
Date Deposited:	04 Nov 2025 17:30
Last Modified:	06 Nov 2025 15:30
URI:	https://ueaeprints.uea.ac.uk/id/eprint/100901
DOI:	10.1177/20416695251350000

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