The influence of lighting on perceived product size: The role of surface curvature and attention

While the affective and behavioural effects of bright lighting in retail settings have been widely explored, its influence on visual perception—particularly product size perception—remains overlooked. This research fills that gap by uncovering a novel link between bright lighting and object shape, showing how their interaction shapes consumer perception. Bridging two previously disconnected streams of literature—lighting and perceived product size—we demonstrate that under bright lighting, convex products are perceived as significantly larger, while concave products appear smaller. Across three controlled experiments, we find that bright lighting heightens visual attention, which amplifies the perceived size of products—but critically, only when the surface curvature is convex. These findings advance theoretical understanding of visual processing in retail environments and offer actionable insights for product display, packaging, and lighting design.