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Philosophical Transactions of the Royal... Jan 2023The dominant inferential approach to human 3D perception assumes a model of spatial encoding based on a physical description of objects and space. Prevailing models... (Review)
Review
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'.
Topics: Humans; Depth Perception; Psychophysics; Distance Perception; Visual Perception; Space Perception
PubMed: 36511412
DOI: 10.1098/rstb.2021.0454 -
Attention, Perception & Psychophysics Oct 2023The present study examined whether and how the mutual perceptual biases of temporal and spatial information, known as the kappa and the tau effects, depend on the...
The present study examined whether and how the mutual perceptual biases of temporal and spatial information, known as the kappa and the tau effects, depend on the duration and spatial extent of sensory stimulation as well as on the magnitude of spatio-temporal discrepancy. Three small circles were presented in succession at different spatial positions. The time points of presentation and the spatial position of the second circle systematically varied. Participants judged either whether the temporal interval between the first and the second circle was longer than the interval between the second and the third circle (Experiment 1) or whether the spatial distance between the first and the second circle was larger than the distance between the second and the third circle (Experiment 2), or both in separate blocks of trials (Experiment 3). The impact of spatial information on temporal perception (i.e., the kappa effect) increased with velocity of motion presumably imputed by the participants to the static displays and decreased with spatio-temporal discrepancy. No inverse biases (i.e., no tau effects) were observed. These results are considered as an indication that integration of spatial and temporal signals follow the same basic principles as multisensory integration of redundant signals, such as those from vision and touch.
Topics: Humans; Photic Stimulation; Space Perception; Vision, Ocular; Time Perception; Touch
PubMed: 36828992
DOI: 10.3758/s13414-023-02678-5 -
Journal of Vision Apr 2024This paper reviews projection models and their perception in realistic pictures, and proposes hypotheses for three-dimensional (3D) shape and space perception in... (Review)
Review
This paper reviews projection models and their perception in realistic pictures, and proposes hypotheses for three-dimensional (3D) shape and space perception in pictures. In these hypotheses, eye fixations, and foveal vision play a central role. Many past theories and experimental studies focus solely on linear perspective. Yet, these theories fail to explain many important perceptual phenomena, including the effectiveness of nonlinear projections. Indeed, few classical paintings strictly obey linear perspective, nor do the best distortion-avoidance techniques for wide-angle computational photography. The hypotheses here employ a two-stage model for 3D human vision. When viewing a picture, the first stage perceives 3D shape for the current gaze. Each fixation has its own perspective projection, but, owing to the nature of foveal and peripheral vision, shape information is obtained primarily for a small region of the picture around the fixation. As a viewer moves their eyes, the second stage continually integrates some of the per-gaze information into an overall interpretation of a picture. The interpretation need not be geometrically stable or consistent over time. It is argued that this framework could explain many disparate pictorial phenomena, including different projection styles throughout art history and computational photography, while being consistent with the constraints of human 3D vision. The paper reviews open questions and suggests new studies to explore these hypotheses.
Topics: Humans; Fixation, Ocular; Form Perception; Depth Perception; Space Perception; Eye Movements; Fovea Centralis
PubMed: 38662346
DOI: 10.1167/jov.24.4.23 -
Journal of Vision Jul 2022Visual systems exploit temporal continuity principles to achieve stable spatial perception, manifested as the serial dependence and central tendency effects. These...
Visual systems exploit temporal continuity principles to achieve stable spatial perception, manifested as the serial dependence and central tendency effects. These effects are posited to reflect a smoothing process whereby past and present information integrates over time to decrease noise and stabilize perception. Meanwhile, the basic spatial coordinate-Cartesian versus polar-that scaffolds the integration process in two-dimensional continuous space remains unknown. The spatial coordinates are largely related to the allocentric and egocentric reference frames and presumably correspond with early and late processing stages in spatial perception. Here, four experiments consistently demonstrate that Cartesian outperforms polar coordinates in characterizing the serial bias-serial dependence and central tendency effect-in two-dimensional continuous spatial perception. The superiority of Cartesian coordinates is robust, independent of task environment (online and offline task), experimental length (short and long blocks), spatial context (shape of visual mask), and response modality (keyboard and mouse). Taken together, the visual system relies on the Cartesian coordinates for spatiotemporal integration to facilitate stable representation of external information, supporting the involvement of allocentric reference frame and top-down modulation in spatial perception over long time intervals.
Topics: Reaction Time; Space Perception
PubMed: 35857298
DOI: 10.1167/jov.22.8.13 -
Trends in Cognitive Sciences Jan 2007Current views of the parietal cortex have difficulty accommodating the human inferior parietal lobe (IPL) within a simple dorsal versus ventral stream dichotomy. In... (Review)
Review
Current views of the parietal cortex have difficulty accommodating the human inferior parietal lobe (IPL) within a simple dorsal versus ventral stream dichotomy. In humans, lesions of the right IPL often lead to syndromes such as hemispatial neglect that are seemingly in accord with the proposal that this region has a crucial role in spatial processing. However, recent imaging and lesion studies have revealed that inferior parietal regions have non-spatial functions, such as in sustaining attention, detecting salient events embedded in a sequence of events and controlling attention over time. Here, we review these findings and show that spatial processes and the visual guidance of action are only part of the repertoire of parietal functions. Although sub-regions in the human superior parietal lobe and intraparietal sulcus contribute to vision-for-action and spatial functions, more inferior parietal regions have distinctly non-spatial attributes that are neither conventionally 'dorsal' nor conventionally 'ventral' in nature.
Topics: Attention; Brain Mapping; Functional Laterality; Parietal Lobe; Space Perception
PubMed: 17134935
DOI: 10.1016/j.tics.2006.10.011 -
Vision Research Sep 2016Objects in our environment are subject to manifold transformations, either of the physical objects themselves or of the object images on the retina. Despite drastic...
Objects in our environment are subject to manifold transformations, either of the physical objects themselves or of the object images on the retina. Despite drastic effects on the objects' physical appearances, we are often able to identify stable objects across transformations and have strong subjective impressions of the transformations themselves. This suggests the brain is equipped with sophisticated mechanisms for inferring both object constancy, and objects' causal history. We employed a dot-matching task to study in geometrical detail the effects of rigid transformations on representations of shape and space. We presented an untransformed 'base shape' on the left side of the screen and its transformed counterpart on the right (rotated, scaled, or both). On each trial, a dot was superimposed at a given location on the contour (Experiment 1) or within and around the shape (Experiment 2). The participant's task was to place a dot at the corresponding location on the right side of the screen. By analyzing correspondence between responses and physical transformations, we tested for object constancy, causal history, and transformation of space. We find that shape representations are remarkably robust against rotation and scaling. Performance is modulated by the type and amount of transformation, as well as by contour saliency. We also find that the representation of space within and around a shape is transformed in line with the shape transformation, as if shape features establish an object-centered reference frame. These findings suggest robust mechanisms for the inference of shape, space and correspondence across transformations.
Topics: Adult; Female; Form Perception; Humans; Male; Pattern Recognition, Visual; Photic Stimulation; Reaction Time; Recognition, Psychology; Space Perception; Young Adult
PubMed: 25937375
DOI: 10.1016/j.visres.2015.04.011 -
Journal of Vision 2015Masking and crowding are major phenomena associated with contextual modulations, but the relationship between them remains unclear. We have recently shown that crowding...
Masking and crowding are major phenomena associated with contextual modulations, but the relationship between them remains unclear. We have recently shown that crowding is apparent in the fovea when the time available for processing is limited, pointing to the strong relationship between crowding in the spatial and temporal domains. Models of crowding emphasize the size (acuity) of the target and the spacing between the target and flankers as the main determinants that predict crowding. Our model, which is based on lateral interactions, posits that masking and crowding are related in the spatial and temporal domains at the fovea and periphery and that both can be explained by the increasing size of the human perceptive field (PF) with increasing eccentricity. We explored the relations between masking and crowding using letter identification and contrast detection by correlating the crowding effect with the estimated size of the PF and with masking under different spatiotemporal conditions. We found that there is a large variability in PF size and crowding effects across observers. Nevertheless, masking and crowding were both correlated with the estimated size of the PF in the fovea and periphery under a specific range of spatiotemporal parameters. Our results suggest that under certain conditions, crowding and masking share common neural mechanisms that underlie the spatiotemporal properties of these phenomena in both the fovea and periphery. These results could explain the transfer of training gains from spatiotemporal Gabor masking to letter acuity, reading, and reduced crowding.
Topics: Adolescent; Adult; Contrast Sensitivity; Crowding; Fovea Centralis; Humans; Perceptual Masking; Reading; Space Perception; Young Adult
PubMed: 26381841
DOI: 10.1167/15.13.10 -
Trends in Cognitive Sciences Nov 2016To interact with the world, we have to make sense of the continuous sensory input conveying information about our environment. A recent surge of studies has investigated... (Review)
Review
To interact with the world, we have to make sense of the continuous sensory input conveying information about our environment. A recent surge of studies has investigated the processes enabling scene understanding, using increasingly complex stimuli and sophisticated analyses to highlight the visual features and brain regions involved. However, there are two major challenges to producing a comprehensive framework for scene understanding. First, scene perception is highly dynamic, subserving multiple behavioral goals. Second, a multitude of different visual properties co-occur across scenes and may be correlated or independent. We synthesize the recent literature and argue that for a complete view of scene understanding, it is necessary to account for both differing observer goals and the contribution of diverse scene properties.
Topics: Brain; Environment; Humans; Sensation; Space Perception; Visual Perception
PubMed: 27769727
DOI: 10.1016/j.tics.2016.09.003 -
Journal of Vision May 2011Crowding occurs when stimuli in the peripheral fields become harder to identify when flanked by other items. This phenomenon has been demonstrated extensively with...
Crowding occurs when stimuli in the peripheral fields become harder to identify when flanked by other items. This phenomenon has been demonstrated extensively with simple patterns (e.g., Gabors and letters). Here, we characterize crowding for everyday objects. We presented three-item arrays of objects and letters, arranged radially and tangentially in the lower visual field. Observers identified the central target, and we measured contrast energy thresholds as a function of target-to-flanker spacing. Object crowding was similar to letter crowding in spatial extent but was much weaker. The average elevation in threshold contrast energy was in the order of 1 log unit for objects as compared to 2 log units for letters and silhouette objects. Furthermore, we examined whether the exterior and interior features of an object are differentially affected by crowding. We used a circular aperture to present or exclude the object interior. Critical spacings for these aperture and "donut" objects were similar to those of intact objects. Taken together, these findings suggest that crowding between letters and objects are essentially due to the same mechanism, which affects equally the interior and exterior features of an object. However, for objects defined with varying shades of gray, it is much easier to overcome crowding by increasing contrast.
Topics: Anisotropy; Contrast Sensitivity; Discrimination, Psychological; Form Perception; Humans; Pattern Recognition, Visual; Perceptual Masking; Photic Stimulation; Sensory Thresholds; Space Perception; Visual Fields; Visual Perception
PubMed: 21613388
DOI: 10.1167/11.6.19 -
Philosophical Transactions of the Royal... Jul 2009The development of sub-disciplines within cognitive neuroscience follows common sense categories such as language, audition, action, memory, emotion and perception among... (Review)
Review
The development of sub-disciplines within cognitive neuroscience follows common sense categories such as language, audition, action, memory, emotion and perception among others. There are also well-established research programmes into temporal perception, spatial perception and mathematical cognition that also reflect the subjective impression of how experience is constructed. There is of course no reason why the brain should respect these common sense, text book divisions and, here, we discuss the contention that generalized magnitude processing is a more accurate conceptual description of how the brain deals with information about time, space, number and other dimensions. The roots of the case for linking magnitudes are based on the use to which magnitude information is put (action), the way in which we learn about magnitudes (ontogeny), shared properties and locations of magnitude processing neurons, the effects of brain lesions and behavioural interference studies. Here, we assess this idea in the context of a theory of magnitude, which proposed common processing mechanisms of time, space, number and other dimensions.
Topics: Humans; Mental Processes; Parietal Lobe; Space Perception; Time Perception
PubMed: 19487186
DOI: 10.1098/rstb.2009.0028