From pictures to reality: modelling the phenomenology and psychophysics of 3D perception

Abstract

The dominant inferential approach to human 3D perception assumes a model of spatial encoding based on a physical description of objects and space. Prevailing models based on this physicalist approach assume that the visual system infers an objective, unitary and mostly veridical representation of the external world. However, careful consideration of the phenomenology of 3D perception challenges these assumptions. I review important aspects of phenomenology, psychophysics and neurophysiology which suggest that human visual perception of 3D objects and space is underwritten by distinct and dissociated spatial encodings that are optimized for specific regions of space. Specifically, I argue that 3D perception is underwritten by at least three distinct encodings for (1) egocentric distance perception at the ambulatory scale, (2) exocentric distance (scaled depth) perception optimized for near space, and (3) perception of object shape and layout (unscaled depth). This tripartite division can more satisfactorily account for the phenomenology, psychophysics and adaptive logic of human 3D perception. This article is part of a discussion meeting issue ‘New approaches to 3D vision’.

Toward a Theory of Perspective Perception in Pictures

“…However, many studies identify inconsistencies and distortions in visual space that cannot be explained by any metric geometry (Linton, 2022): distortions of estimated depth due to irrelevant factors (Johnston, 1991;Todd and Norman, 2003;Campagnoli et al, 2022;Vishwanath, 2014), inconsistencies between estimates of depth, slant, curvature, and/or shape (Di Luca et al, 2010;Koenderink, 1998;Loomis et al, 2002;Koenderink et al, 2002), and internal inconsistency of multiple relative judgements (Koenderink et al, 2008;Svarverud et al, 2012;Vuong et al, 2019). Some recent theories explain inconsistent results by treating visual space as fragmentary in some way, with, for example, separate representations for different surfaces (Koenderink, 1998), different distance ranges (Vishwanath, 2022), or for action versus perception (Goodale and Milner, 1992).…”

New Approaches to 3D Vision

“…Tripartite model: Perhaps we should think of visual spaces, rather than one single visual space. In this issue Dhanraj Vishwanath [ 334 ] argues for a ‘tripartite model’ of visual space, according to which there are three ‘distinct and dissociated encodings' for (a) 3D shape, (b) ‘egocentric’ (observer to object) distances, and (c) ‘exocentric’ (object to object) distances. However, often viewing conditions will only support one or two of these encodings, explaining the ‘inconsistencies’ reported in the literature above.…”