New Approaches to Visual Scale and Visual Shape

Human 3D vision is thought to triangulate the size, distance, direction, and 3D shape of objects using vision from the two eyes. But all four of these capacities rely on the visual system knowing where the eyes are pointing. Dr Linton's experimental work on size and distance challenge this account, suggesting a purely retinal account of visual size and distance, and likely direction and 3D shape. This requires new accounts of visual scale and visual shape. For visual scale, he argues that observers rely on natural scene statistics to associate accentuated stereo depth (largely from horizontal disparities) with closer distances. This implies that depth / shape is resolved before size and distance. For visual shape, he argues that depth / shape from the two eyes is a solution to a different problem (rivalry eradication between two retinal images treated as if they are from the same viewpoint), rather than the visual system attempting to infer scene geometry (by treating the two retinal images as two different views of the same scene from different viewpoints). Dr Linton also draws upon his book, which questions whether other depth cues (perspective, shading, motion) really have any influence on this process.