Distance and Size Perception in Astronauts during  Long-Duration Spaceflight

Clément, Gilles; Skinner, Anna; Lathan, Corinna

doi:10.3390/life3040524

Cited by 50 publications

(49 citation statements)

References 27 publications

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“…If participants felt they were taller than usual, then this could cause a perceptual rescaling of the size of the room a la Alice in Wonderland. When unsure of head position in the environment, either because of an unusual posture or in microgravity (Clément et al, 2013), the depth system may get recalibrated resulting in a rescaling of the apparent size of the environment with corresponding errors in size perception.…”

Section: Discussionmentioning

confidence: 99%

“…Perceived distances were consistently underestimated during either shortterm exposure to microgravity using parabolic flight (Clément, Lathan, & Lockerd, 2008) or long term exposure on the International Space Station (Clément, Skinner, & Lathan, 2013) leading to perceptual distortions of three dimensional objects. In the absence of a gravitational reference it seems that objects appear closer than in the presence of orientation cues.…”

Section: Introductionmentioning

confidence: 98%

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Perceived distance depends on the orientation of both the body and the visual environment

Harris

Mander

2014

Journal of Vision

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Models of depth perception typically omit the orientation and height of the observer despite the potential usefulness of the height above the ground plane and the need to know about head position to interpret retinal disparity information. To assess the contribution of orientation to perceived distance, we used the York University Tumbled and Tumbling Room facilities to modulate both perceived and actual body orientation. These facilities are realistically decorated rooms that can be systematically arranged to vary the relative orientation of visual, gravity, and body cues to upright. To assess perceived depth we exploited size/distance constancy. Observers judged the perceived length of a visual line (controlled by a QUEST adaptive procedure) projected on to the wall of the facilities, relative to the length of an unseen iron rod held in their hands. In the Tumbled Room (viewing distance 337 cm) the line was set about 10% longer when participants were supine compared to when they were upright. In the Tumbling Room (viewing distance 114 cm), the line was set about 11% longer when participants were either supine or made to feel that they were supine by the orientation of the room. Matching a longer visual line to the reference rod is compatible with the opposite wall being perceived as closer. The effect was modulated by whether viewing was monocular or binocular at a viewing distance of 114 cm but not at 337 cm suggesting that reliable binocular cues can override the effect.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 98%

Perceived distance depends on the orientation of both the body and the visual environment

Harris

Mander

2014

Journal of Vision

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“…Microgravity experiments showed that visual perception of horizontal depth is influenced by altered vestibular signals [19]. For example, perceived distances were underestimated during either short-term exposure to microgravity using parabolic flight [20] or long term exposure on the International Space Station [21] leading to perceptual distortions of three dimensional space. However, the vestibular contribution to elevation biases in visual depth perception remains under-investigated.…”

Section: Introductionmentioning

confidence: 99%

Up, Down, Near, Far: An Online Vestibular Contribution to Distance Judgement

et al. 2017

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Whether a visual stimulus seems near or far away depends partly on its vertical elevation. Contrasting theories suggest either that perception of distance could vary with elevation, because of memory of previous upwards efforts in climbing to overcome gravity, or because of fear of falling associated with the downwards direction. The vestibular system provides a fundamental signal for the downward direction of gravity, but the relation between this signal and depth perception remains unexplored. Here we report an experiment on vestibular contributions to depth perception, using Virtual Reality. We asked participants to judge the absolute distance of an object presented on a plane at different elevations during brief artificial vestibular inputs. Relative to distance estimates collected with the object at the level of horizon, participants tended to overestimate distances when the object was presented above the level of horizon and the head was tilted upward and underestimate them when the object was presented below the level of horizon. Interestingly, adding artificial vestibular inputs strengthened these distance biases, showing that online multisensory signals, and not only stored information, contribute to such distance illusions. Our results support the gravity theory of depth perception, and show that vestibular signals make an on-line contribution to the perception of effort, and thus of distance.

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“…Positive errors correspond to underestimations of the adjustable dimension and/or to overestimations of the reference dimension. Thus, the present experimental paradigm, similar to the one previously used by Clément et al ( , 2013, allows the quantification of the perceptive distortions of one dimension relative to another, but cannot lead to a measure of the absolute perceptive distortions for each dimension separately (see Annex 1). Table 1 shows that the error in estimating one dimension has opposite effects for the two tasks performed within a given plane.…”

Section: Discussionmentioning

confidence: 99%

“…In an analogy with previous experiments on visual perception (Clément et al , 2013, our paradigm was conceptually designed to detect distortions in the perception of a purported 3D cube. The sequential nature of haptic perception induced us, however, to focus each trial on the comparison of the relative size between two out of three possible dimensions.…”

Section: Methodsmentioning

confidence: 99%

Modality-independent effect of gravity in shaping the internal representation of 3D space

Morfoisse

Gabriela

Angelini

et al. 2020

Preprint

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Human visual 3D perception is flawed by distortions, which are influenced by non-visual factors, such as gravitational vestibular signals. Distinct hypotheses regarding the sensory processing stage at which gravity acts may explain the influence of gravity: 1) a direct effect on the visual system, 2) a shaping of the internal representation of space that is used to interpret sensory signals, or 3) a role in the ability to build multiple, modalityspecific, internal depictions of the perceived object. To test these hypotheses, we performed experiments comparing visual versus haptic 3D perception, and the effects of microgravity on these two senses. The results show that visual and haptic perceptual anisotropies reside in body-centered, and not gravity-centered, planes, suggesting an ego-centric encoding of the information for both sensory modalities. Although coplanar, the perceptual distortions of the two sensory modalities are in opposite directions: depth is visually underestimated, but haptically overestimated, with respect to height and width. Interestingly microgravity appears to amplify the 'terrestrial' distortions of both senses. Through computational modeling, we show that these findings are parsimoniously predicted only by a gravity facilitation of cross-modal sensory reconstructions, corresponding to Hypothesis 3. This theory is able to explain not only how gravity can shape egocentric perceptions, but also the unexpected opposite effect of gravity on visual and haptic 3D perception. Overall, these results suggest that the brain uses gravity as a stable reference cue to reconstruct concurrent, modality-specific internal representations of 3D objects even when they are sensed through only one sensory channel. Up-Down Longitudinal B C A

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Distance and Size Perception in Astronauts during Long-Duration Spaceflight

Cited by 50 publications

References 27 publications

Perceived distance depends on the orientation of both the body and the visual environment

Perceived distance depends on the orientation of both the body and the visual environment

Up, Down, Near, Far: An Online Vestibular Contribution to Distance Judgement

Modality-independent effect of gravity in shaping the internal representation of 3D space

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