The conscious awareness of visual space: A tripartite encoding model.

Abstract

The prevailing model of 3D vision proposes that the visual system recovers a single objective and internally consistent representation of physical 3D space based on a process of ideal-observer probabilistic inference. A significant challenge for this model has been in explaining the contents of our subjective awareness of visual space. Here I argue that integrating phenomenological observations, empirical data, evolutionary logic and neurophysiological evidence leads to the conjecture that the human conscious awareness of visual space is underwritten by multiple, sometimes mutually inconsistent, spatial encodings.By assessing four primary competencies in the conscious awareness of space, three major types of spatial encodings are conjectured. Among the most primitive of these is proposed to support the competency of the conscious awareness of distance at an ambulatory scale (operationally defined as egocentric distance) and is hypothesised to originate in medial temporal allocortex. The second is proposed to support the competency of awareness of object layout and 3D shape without scale (operationally, relative depth). This encoding is hypothesised to have evolved from more primitive encodings that provide a depth-ordered segmentation of the visual field. The third encoding is proposed to support the competency of fine-grained awareness of intra-and inter-object spatial separation in near space (operationally, scaled or absolute depth) and instantiated in the posterior parietal cortex. This encoding is conjectured to underlie the phenomenology of object solidity, spatial separation, tangibility and object realness that is often referred to as stereopsis. The combined effect of the first and third competencies (ambulatory distance and near-space scaled spatial separation) is conjectured to contribute to the feeling of spatial immersion/presence.

Experimental phenomenology, a challenge.

“…The role of completeness is explored in terms of its inner logic and through an accurate phenomenal analysis of counterexamples and limiting or critical conditions. Dhanraj Vishwanath (2021) contributes an article which extends his previous work on a “dual depth map” hypothesis aimed at explaining phenomena in the conscious awareness of three-dimensional space. The current work hypothesizes a third distinct map that underlies our awareness and anticipation of movement at an ambulatory scale.…”

“…Neuroscience and experimental phenomenology, however correlated, are nevertheless different sciences, because their observables, principles, methods, measurement and explanation are nether equivalent nor interchangeable. In particular, in the last years experimental phenomenology enriched the Gestalt tradition with new advancements, among which the identification of new principles of organization (the Principle of meaning and the Principle of reversed contrast) and the demonstration of their dominant role in shape formation when compared with other Principles such as similarity, Prägnanz, and good continuation (Pinna, 2010(Pinna, , 2021Pinna & Albertazzi, 2010); the discovery of new junctions (I-Junctions) besides T-junctions and Y-Junctions (Pinna & Conti, 2021); visual completion in drawings perceived as flat knots (Massironi & Bressanelli, 2002); the impression of self-luminosity in the glare effect (Zavagno & Caputo, 2001); the presence of natural associations in cross-modal complex stimuli of experience (Albertazzi et al, 2015(Albertazzi et al, , 2016; the development of Osgood semantic differential in sensory scales (da Pos & Pietto, 2010), and the qualitative and phenomenological components of space and 3D object perception (Vishwanath, 2014(Vishwanath, , 2021. These advancements have been brought on by the methods of description, demonstration, and experimental verification in line with the main tenets of experimental phenomenology.…”

Minimal theory of 3D vision: new approach to visual scale and visual shape

“…The two leading accounts of pictorial depth in the vision science literature treat it either as (i) a weak form of normal depth perception [53], or (ii) the perception of 3D shape [49,[54][55][56]. Indeed, when I developed my purely cognitive account of pictorial depth in 2017 ([41, pp.…”

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

“…This effect is most readily apparent phenomenologically when viewing dashed lines dividing a roadway. Moreover, there is the phenomenological impression, as one walks along the road, of the dashed lines ‘growing’ or ‘stretching’ in length as one comes closer to each interval [ 46 ]. While the finding that egocentric distance perception is accurate over a wide range of distances is consistent with inferential models (which assume the derivation of a veridical representation of space), the finding of the dissociation between egocentric distance and exocentric (inter-object) distance or interval perception, along with other associated phenomenology, cannot be accommodated in such models.…”

“…However, as previously mentioned, the phenomenological introspection of egocentric and exocentric distance perception beyond personal space (greater than 2 m) reveals a clear dissociation, where the impression of exocentric depth separation appears to rapidly diminish with increasing distance (even for very large depth separations), while the phenomenological impression of distance to objects does not diminish in the same way. Moreover, closing one eye when viewing a real scene substantially diminishes the impression of spatial separation between objects within action space, but the perception of the distance to an object appears unchanged (see [ 18 , 46 ]). The psychophysical data by Loomis and collaborators [ 39 , 43 ] described in the Introduction confirms this phenomenological dissociation.…”