Schedule of Events | Search Abstracts | Invited Symposia | Symposia | Poster Sessions | Data Blitz

Shape from shading as a marker of lateralization changes across the lifespan

Poster Session E - Monday, March 9, 2026, 2:30 – 4:30 pm PDT, Fairview/Kitsilano Ballroom

Marjola Peca¹ (), Giovanni d'Avossa¹, Ayelet Sapir²; ¹Bangor University, ²University of Greenwich

Shape from shading refers to the ability to judge whether a surface appears convex or concave based on shading information relative to an assumed light source. Observers typically assume that the light source is positioned above and to the left. This left bias is thought to reflect right-hemisphere dominance in processing shape from shading. Furthermore, while younger adults tend to show a strong left bias, older adults have on average a reduced left bias, which has been associated with decreased lateralization during aging. However, it remains unclear when this shift begins to emerge across adulthood. In the current study, we investigated the pattern of shape-from-shading bias across the adult lifespan, from 18 to 91 years of age. Participants completed a shape-from-shading task in which they judged whether shaded shapes appeared convex or concave. We replicated the previously observed difference between younger and older adults. Some older participants had a left bias, while others had a central or even right bias. In contrast, younger adults had a left bias. Importantly, the reduced left bias in older age resulted from a continuous change across adulthood. This pattern suggests that age-related changes in shape-from-shading perception reflect a gradual decline in hemispheric lateralization. Shape-from-shading may therefore serve as a reliable longitudinal tool for tracking lateralization changes across the lifespan.

Topic Area: ATTENTION: Development & aging