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 (IPE), 16 (4). ISSN 2041-6695 (Online) (doi:10.1177/20416695251350000)

Preview

PDF (Open Access Article) 50107 SAPIR_Three-Dimensional_Shape_From_Shading_Is_Modulated_By_Top-Down_Attention_(OA)_2025.pdf - Published Version Available under License Creative Commons Attribution. Download (2MB) | Preview

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:	Awarded best early career paper.
Uncontrolled Keywords:	three-dimensional shape, depth perception, shape-from shading, top-down attention, event-related potentials
Subjects:	B Philosophy. Psychology. Religion > BF Psychology Q Science > Q Science (General) R Medicine > RE Ophthalmology
Faculty / School / Research Centre / Research Group:	Faculty of Education, Health & Human Sciences Faculty of Education, Health & Human Sciences > Institute for Lifecourse Development Faculty of Education, Health & Human Sciences > Institute for Lifecourse Development > Centre for Thinking and Learning Faculty of Education, Health & Human Sciences > School of Human Sciences (HUM)
Last Modified:	06 Mar 2026 13:32
URI:	https://gala.gre.ac.uk/id/eprint/50107

Actions (login required)

View Item

Downloads