1
|
Loued-Khenissi L, Pfeiffer C, Saxena R, Adarsh S, Scaramuzza D. Microgravity induces overconfidence in perceptual decision-making. Sci Rep 2023; 13:9727. [PMID: 37322248 PMCID: PMC10272216 DOI: 10.1038/s41598-023-36775-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Accepted: 06/09/2023] [Indexed: 06/17/2023] Open
Abstract
Does gravity affect decision-making? This question comes into sharp focus as plans for interplanetary human space missions solidify. In the framework of Bayesian brain theories, gravity encapsulates a strong prior, anchoring agents to a reference frame via the vestibular system, informing their decisions and possibly their integration of uncertainty. What happens when such a strong prior is altered? We address this question using a self-motion estimation task in a space analog environment under conditions of altered gravity. Two participants were cast as remote drone operators orbiting Mars in a virtual reality environment on board a parabolic flight, where both hyper- and microgravity conditions were induced. From a first-person perspective, participants viewed a drone exiting a cave and had to first predict a collision and then provide a confidence estimate of their response. We evoked uncertainty in the task by manipulating the motion's trajectory angle. Post-decision subjective confidence reports were negatively predicted by stimulus uncertainty, as expected. Uncertainty alone did not impact overt behavioral responses (performance, choice) differentially across gravity conditions. However microgravity predicted higher subjective confidence, especially in interaction with stimulus uncertainty. These results suggest that variables relating to uncertainty affect decision-making distinctly in microgravity, highlighting the possible need for automatized, compensatory mechanisms when considering human factors in space research.
Collapse
Affiliation(s)
- Leyla Loued-Khenissi
- Laboratory for Behavioral Neurology and Imaging of Cognition, Neuroscience Department, Medical School, University of Geneva, Geneva, Switzerland.
- Neuro-X Institute, École Polytechnique Fédérale de Lausanne, Geneva, Switzerland.
| | - Christian Pfeiffer
- Robotics and Perception Group, University of Zurich, Zurich, Switzerland
| | - Rupal Saxena
- Robotics and Perception Group, University of Zurich, Zurich, Switzerland
| | - Shivam Adarsh
- Robotics and Perception Group, University of Zurich, Zurich, Switzerland
| | - Davide Scaramuzza
- Robotics and Perception Group, University of Zurich, Zurich, Switzerland
| |
Collapse
|
2
|
Kuldavletova O, Navarro Morales DC, Quarck G, Denise P, Clément G. Spaceflight alters reaction time and duration judgment of astronauts. Front Physiol 2023; 14:1141078. [PMID: 37007995 PMCID: PMC10063900 DOI: 10.3389/fphys.2023.1141078] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Accepted: 03/03/2023] [Indexed: 03/19/2023] Open
Abstract
We report a study on astronauts aimed at characterizing duration judgment before, during, and after long-duration stays on board the International Space Station. Ten astronauts and a control group of 15 healthy (non-astronaut) participants performed a duration reproduction task and a duration production task using a visual target duration ranging from 2 to 38 s. Participants also performed a reaction time test for assessing attention. Compared to control participants and preflight responses, the astronauts’ reaction time increased during spaceflight. Also, during spaceflight, time intervals were under-produced while counting aloud and under-reproduced when there was a concurrent reading task. We hypothesize that time perception during spaceflight is altered by two mechanisms: (a) an acceleration of the internal clock through the changes in vestibular inputs in microgravity, and (b) difficulties in attention and working memory when a concurrent reading task is present. Prolonged isolation in confined areas, weightlessness, stress related to workload, and high-performance expectations could account for these cognitive impairments.
Collapse
|
3
|
Navarro Morales DC, Kuldavletova O, Quarck G, Denise P, Clément G. Time perception in astronauts on board the International Space Station. NPJ Microgravity 2023; 9:6. [PMID: 36658133 PMCID: PMC9852442 DOI: 10.1038/s41526-023-00250-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2022] [Accepted: 01/10/2023] [Indexed: 01/20/2023] Open
Abstract
We perceive the environment through an elaborate mental representation based on a constant integration of sensory inputs, knowledge, and expectations. Previous studies of astronauts on board the International Space Station have shown that the mental representation of space, such as the perception of object size, distance, and depth, is altered in orbit. Because the mental representations of space and time have some overlap in neural networks, we hypothesized that perception of time would also be affected by spaceflight. Ten astronauts were tested before, during, and after a 6-8-month spaceflight. Temporal tasks included judging when one minute had passed and how long it had been since the start of the workday, lunch, docking of a vehicle, and a spacewalk. Compared to pre-flight estimates, there is a relative overestimation for the 1-min interval during the flight and a relative underestimation of intervals of hours in duration. However, the astronauts quite accurately estimated the number of days since vehicle dockings and spacewalks. Prolonged isolation in confined areas, stress related to workload, and high-performance expectations are potential factors contributing to altered time perception of daily events. However, reduced vestibular stimulations and slower motions in weightlessness, as well as constant references to their timeline and work schedule could also account for the change in the estimation of time by the astronauts in space.
Collapse
Affiliation(s)
- Deborah C. Navarro Morales
- grid.412043.00000 0001 2186 4076UNICAEN, INSERM, CHU Caen, Normandy University, COMETE, CYCERON, Esplanade de la Paix, 14032 Caen, France
| | - Olga Kuldavletova
- grid.412043.00000 0001 2186 4076UNICAEN, INSERM, CHU Caen, Normandy University, COMETE, CYCERON, Esplanade de la Paix, 14032 Caen, France
| | - Gaëlle Quarck
- grid.412043.00000 0001 2186 4076UNICAEN, INSERM, CHU Caen, Normandy University, COMETE, CYCERON, Esplanade de la Paix, 14032 Caen, France
| | - Pierre Denise
- grid.412043.00000 0001 2186 4076UNICAEN, INSERM, CHU Caen, Normandy University, COMETE, CYCERON, Esplanade de la Paix, 14032 Caen, France
| | - Gilles Clément
- grid.412043.00000 0001 2186 4076UNICAEN, INSERM, CHU Caen, Normandy University, COMETE, CYCERON, Esplanade de la Paix, 14032 Caen, France
| |
Collapse
|
4
|
Karpinskaia VY, Pechenkova EV, Zelenskaya IS, Lyakhovetskii VA. Vision for Perception and Vision for Action in Space Travelers. Front Physiol 2022; 13:806578. [PMID: 35360254 PMCID: PMC8963356 DOI: 10.3389/fphys.2022.806578] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Accepted: 02/10/2022] [Indexed: 11/13/2022] Open
Affiliation(s)
- Valeriia Yu. Karpinskaia
- Laboratory of Neurovisualization, N.P. Bechtereva Institute of the Human Brain (Russian Academy of Sciences), St. Petersburg, Russia
- *Correspondence: Valeriia Yu. Karpinskaia
| | | | - Inna S. Zelenskaya
- Laboratory of Gravitational Physiology of the Sensorimotor System, Institute of Biomedical Problems, Russian Academy of Sciences, Moscow, Russia
| | - Vsevolod A. Lyakhovetskii
- Laboratory of Movement Physiology, Pavlov Institute of Physiology, Russian Academy of Sciences, St. Petersburg, Russia
| |
Collapse
|
5
|
Judgments of Object Size and Distance across Different Virtual Reality Environments: A Preliminary Study. APPLIED SCIENCES-BASEL 2021. [DOI: 10.3390/app112311510] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Emerging technologies offer the potential to expand the domain of the future workforce to extreme environments, such as outer space and alien terrains. To understand how humans navigate in such environments that lack familiar spatial cues this study examined spatial perception in three types of environments. The environments were simulated using virtual reality. We examined participants’ ability to estimate the size and distance of stimuli under conditions of minimal, moderate, or maximum visual cues, corresponding to an environment simulating outer space, an alien terrain, or a typical cityscape, respectively. The findings show underestimation of distance in both the maximum and the minimum visual cue environment but a tendency for overestimation of distance in the moderate environment. We further observed that depth estimation was substantially better in the minimum environment than in the other two environments. However, estimation of height was more accurate in the environment with maximum cues (cityscape) than the environment with minimum cues (outer space). More generally, our results suggest that familiar visual cues facilitated better estimation of size and distance than unfamiliar cues. In fact, the presence of unfamiliar, and perhaps misleading visual cues (characterizing the alien terrain environment), was more disruptive than an environment with a total absence of visual cues for distance and size perception. The findings have implications for training workers to better adapt to extreme environments.
Collapse
|
6
|
Salatino A, Iacono C, Gammeri R, Chiadò ST, Lambert J, Sulcova D, Mouraux A, George MS, Roberts DR, Berti A, Ricci R. Zero gravity induced by parabolic flight enhances automatic capture and weakens voluntary maintenance of visuospatial attention. NPJ Microgravity 2021; 7:29. [PMID: 34315902 PMCID: PMC8316350 DOI: 10.1038/s41526-021-00159-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Accepted: 06/28/2021] [Indexed: 11/30/2022] Open
Abstract
Orienting attention in the space around us is a fundamental prerequisite for willed actions. On Earth, at 1 g, orienting attention requires the integration of vestibular signals and vision, although the specific vestibular contribution to voluntary and automatic components of visuospatial attention remains largely unknown. Here, we show that unweighting of the otolith organ in zero gravity during parabolic flight, selectively enhances stimulus-driven capture of automatic visuospatial attention, while weakening voluntary maintenance of covert attention. These findings, besides advancing our comprehension of the basic influence of the vestibular function on voluntary and automatic components of visuospatial attention, may have operational implications for the identification of effective countermeasures to be applied in forthcoming human deep space exploration and habitation, and on Earth, for patients’ rehabilitation.
Collapse
Affiliation(s)
- Adriana Salatino
- Department of Psychology, University of Turin, Turin, Italy. .,Institute of Neuroscience (IoN), Université Catholique de Louvain Brussels, Brussels, Belgium.
| | - Claudio Iacono
- Department of Psychology, University of Turin, Turin, Italy
| | | | | | - Julien Lambert
- Institute of Neuroscience (IoN), Université Catholique de Louvain Brussels, Brussels, Belgium
| | - Dominika Sulcova
- Institute of Neuroscience (IoN), Université Catholique de Louvain Brussels, Brussels, Belgium
| | - André Mouraux
- Institute of Neuroscience (IoN), Université Catholique de Louvain Brussels, Brussels, Belgium
| | - Mark S George
- Department of Psychiatry and Behavioral Sciences, Medical University of South Carolina, Charleston, SC, USA.,Ralph H. Johnson VA Medical Center, Charleston, SC, USA
| | - Donna R Roberts
- Department of of Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC, USA
| | - Anna Berti
- Department of Psychology, University of Turin, Turin, Italy
| | - Raffaella Ricci
- Department of Psychology, University of Turin, Turin, Italy. .,Department of Psychiatry and Behavioral Sciences, Medical University of South Carolina, Charleston, SC, USA.
| |
Collapse
|
7
|
Boada M, Perez-Poch A, Ballester M, García-Monclús S, González DV, García S, Barri PN, Veiga A. Microgravity effects on frozen human sperm samples. J Assist Reprod Genet 2020; 37:2249-2257. [PMID: 32683528 PMCID: PMC7492354 DOI: 10.1007/s10815-020-01877-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Accepted: 06/29/2020] [Indexed: 10/23/2022] Open
Abstract
PURPOSE Microgravity has severe effects on cellular and molecular structures as well as on metabolic interactions. The aim of this study is to investigate the effects of microgravity (μg) exposure on human frozen sperm samples. METHODS Sibling samples from 15 normozoospermic healthy donors were frozen using glycerol as cryoprotectant and analyzed under microgravity and ground conditions. Microgravity was obtained by parabolic flights using a CAP10B plane. The plane executed 20 parabolic maneuvers with a mean of 8.5 s of microgravity for each parabola. RESULTS Frozen sperm samples preserved in cryostraws and stored in a secure and specific nitrogen vapor cryoshipper do not suffer significant alterations after μg exposure. Comparing the study group (μg) and the control group (1 g), similar results were obtained in the main parameters studied: sperm motility (M/ml) 13.72 ± 12.57 vs 13.03 ± 12.13 (- 0.69 95% CI [- 2.9; 1.52]), progressive a + b sperm motility (%) 21.83 ± 11.69 vs 22.54 ± 12.83 (0.03 95% CI [- 0.08; 0.15]), sperm vitality (%) 46.42 ± 10.81 vs 44.62 ± 9.34 (- 0.04 95% CI [- 0.13; 0.05]), morphologically normal spermatozoa (%) 7.03 ± 2.61 vs 8.09 ± 3.61 (0.12 95% CI [0.01; 0.24]), DNA sperm fragmentation by SCD (%) 13.33 ± 5.12 vs 13.88 ± 6.14 (0.03 95% CI [- 0.09; 0.16]), and apoptotic spermatozoa by MACS (%) 15.47 ± 15.04 vs 23.80 ± 23.63 (- 0.20 95% CI [- 0.66; 1.05]). CONCLUSION The lack of differences obtained between frozen samples exposed to μg and those maintained in ground conditions provides the possibility of considering the safe transport of human male gametes to space. Nevertheless, further research is needed to validate the results and to consider the possibility of creating a human sperm bank outside the Earth. TRIAL REGISTRATION NUMBER ClinicalTrials.gov: NCT03760783.
Collapse
Affiliation(s)
- M Boada
- Women's Health Dexeus, Department of Obstetrics, Gynaecology and Reproduction, Hospital Universitari Dexeus, Avinguda Carles III 71-75, 08028, Barcelona, Spain.
| | - A Perez-Poch
- Universitat Politècnica de Catalunya, UPC BarcelonaTech, EEBE Campus Diagonal-Besòs, C. E. Maristany 16, 08019, Barcelona, Spain
| | - M Ballester
- Women's Health Dexeus, Department of Obstetrics, Gynaecology and Reproduction, Hospital Universitari Dexeus, Avinguda Carles III 71-75, 08028, Barcelona, Spain
| | - S García-Monclús
- Women's Health Dexeus, Department of Obstetrics, Gynaecology and Reproduction, Hospital Universitari Dexeus, Avinguda Carles III 71-75, 08028, Barcelona, Spain
| | - D V González
- Aeroclub Barcelona-Sabadell, Sabadell Airport, Carretera de Bellaterra s/n, 08205 Sabadell, Barcelona, Spain
| | - S García
- Women's Health Dexeus, Unit of Biostatistics, Avinguda Carles III 71-75, 08028, Barcelona, Spain
| | - P N Barri
- Women's Health Dexeus, Department of Obstetrics, Gynaecology and Reproduction, Hospital Universitari Dexeus, Avinguda Carles III 71-75, 08028, Barcelona, Spain
| | - A Veiga
- Women's Health Dexeus, Department of Obstetrics, Gynaecology and Reproduction, Hospital Universitari Dexeus, Avinguda Carles III 71-75, 08028, Barcelona, Spain
- Barcelona Stem Cell Bank, Centre of Regenerative Medicine in Barcelona, Hospital Duran i Reynals, Gran Via de l'Hospitalet 199, 08908 Hospitalet de Llobregat, Barcelona, Spain
| |
Collapse
|
8
|
Clément G, Wood SJ, Paloski WH, Reschke MF. Changes in gain of horizontal vestibulo-ocular reflex during spaceflight. J Vestib Res 2019; 29:241-251. [PMID: 31306145 PMCID: PMC9249294 DOI: 10.3233/ves-190670] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
BACKGROUND: The vestibulo-ocular reflex (VOR) is a basic function of the vestibular system that stabilizes gaze during head movement. Investigations on how spaceflight affects VOR gain and phase are few, and the magnitude of observed changes varies considerably and depends on the protocols used. OBJECTIVE: We investigated whether the gain and phase of the VOR in darkness and the visually assisted VOR were affected during and after spaceflight. METHODS: We measured the VOR gain and phase of 4 astronauts during and after a Space Shuttle spaceflight while the subjects voluntary oscillated their head around the yaw axis at 0.33 Hz or 1 Hz and fixed their gaze on a visual target (VVOR) or imagined this target when vision was occluded (DVOR). Eye position was recorded using electrooculography and angular velocity of the head was recorded with angular rate sensors. RESULTS: The VVOR gain at both oscillation frequencies remained near unity for all trials. DVOR gain was more variable inflight and postflight. Early inflight and immediately after the flight, DVOR gain was lower than before the flight. The phase between head and eye position was not altered by spaceflight. CONCLUSION: The decrease in DVOR gain early in the flight and after the flight reflects adaptive changes in central integration of vestibular and proprioceptive sensory inputs during active head movements.
Collapse
Affiliation(s)
- Gilles Clément
- KBR, Houston, USA.,Lyon Neuroscience Research Center, Bron, France
| | - Scott J Wood
- Neuroscience Laboratories, NASA Johnson Space Center, Houston, USA
| | | | | |
Collapse
|
9
|
Reschke MF, Clément G. Vestibular and Sensorimotor Dysfunction During Space Flight. CURRENT PATHOBIOLOGY REPORTS 2018. [DOI: 10.1007/s40139-018-0173-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
|
10
|
|
11
|
Jörges B, López-Moliner J. Gravity as a Strong Prior: Implications for Perception and Action. Front Hum Neurosci 2017; 11:203. [PMID: 28503140 PMCID: PMC5408029 DOI: 10.3389/fnhum.2017.00203] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Accepted: 04/07/2017] [Indexed: 11/29/2022] Open
Abstract
In the future, humans are likely to be exposed to environments with altered gravity conditions, be it only visually (Virtual and Augmented Reality), or visually and bodily (space travel). As visually and bodily perceived gravity as well as an interiorized representation of earth gravity are involved in a series of tasks, such as catching, grasping, body orientation estimation and spatial inferences, humans will need to adapt to these new gravity conditions. Performance under earth gravity discrepant conditions has been shown to be relatively poor, and few studies conducted in gravity adaptation are rather discouraging. Especially in VR on earth, conflicts between bodily and visual gravity cues seem to make a full adaptation to visually perceived earth-discrepant gravities nearly impossible, and even in space, when visual and bodily cues are congruent, adaptation is extremely slow. We invoke a Bayesian framework for gravity related perceptual processes, in which earth gravity holds the status of a so called “strong prior”. As other strong priors, the gravity prior has developed through years and years of experience in an earth gravity environment. For this reason, the reliability of this representation is extremely high and overrules any sensory information to its contrary. While also other factors such as the multisensory nature of gravity perception need to be taken into account, we present the strong prior account as a unifying explanation for empirical results in gravity perception and adaptation to earth-discrepant gravities.
Collapse
Affiliation(s)
- Björn Jörges
- Department of Cognition, Development and Psychology of Education, Faculty of Psychology, Universitat de BarcelonaCatalonia, Spain.,Institut de Neurociències, Universitat de BarcelonaCatalonia, Spain
| | - Joan López-Moliner
- Department of Cognition, Development and Psychology of Education, Faculty of Psychology, Universitat de BarcelonaCatalonia, Spain.,Institut de Neurociències, Universitat de BarcelonaCatalonia, Spain
| |
Collapse
|
12
|
Cebolla AM, Petieau M, Dan B, Balazs L, McIntyre J, Cheron G. "Cerebellar contribution to visuo-attentional alpha rhythm: insights from weightlessness". Sci Rep 2016; 6:37824. [PMID: 27883068 PMCID: PMC5121637 DOI: 10.1038/srep37824] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Accepted: 11/02/2016] [Indexed: 11/23/2022] Open
Abstract
Human brain adaptation in weightlessness follows the necessity to reshape the dynamic integration of the neural information acquired in the new environment. This basic aspect was here studied by the electroencephalogram (EEG) dynamics where oscillatory modulations were measured during a visuo-attentional state preceding a visuo-motor docking task. Astronauts in microgravity conducted the experiment in free-floating aboard the International Space Station, before the space flight and afterwards. We observed stronger power decrease (~ERD: event related desynchronization) of the ~10 Hz oscillation from the occipital-parietal (alpha ERD) to the central areas (mu ERD). Inverse source modelling of the stronger alpha ERD revealed a shift from the posterior cingulate cortex (BA31, from the default mode network) on Earth to the precentral cortex (BA4, primary motor cortex) in weightlessness. We also observed significant contribution of the vestibular network (BA40, BA32, and BA39) and cerebellum (lobule V, VI). We suggest that due to the high demands for the continuous readjustment of an appropriate body posture in free-floating, this visuo-attentional state required more contribution from the motor cortex. The cerebellum and the vestibular network involvement in weightlessness might support the correction signals processing necessary for postural stabilization, and the increased demand to integrate incongruent vestibular information.
Collapse
Affiliation(s)
- A. M. Cebolla
- Laboratory of Neurophysiology and Movement Biomechanics, CP640, ULB Neuroscience Institute, Université Libre de Bruxelles, 1070 Brussels, Belgium
| | - M. Petieau
- Laboratory of Neurophysiology and Movement Biomechanics, CP640, ULB Neuroscience Institute, Université Libre de Bruxelles, 1070 Brussels, Belgium
| | - B. Dan
- Laboratory of Neurophysiology and Movement Biomechanics, CP640, ULB Neuroscience Institute, Université Libre de Bruxelles, 1070 Brussels, Belgium
- Inkendaal Rehabilitation Hospital, 1602 Vlezenbeek, Belgium
| | - L. Balazs
- Institute for Psychology of the Hungarian Academy of Sciences, Department of Experimental Psychology, 1132 Budapest, Hungary
| | - J. McIntyre
- LNRS/CNRS-Université René Descartes Paris V, 75006, Paris, France
| | - G. Cheron
- Laboratory of Neurophysiology and Movement Biomechanics, CP640, ULB Neuroscience Institute, Université Libre de Bruxelles, 1070 Brussels, Belgium
- Laboratory of Electrophysiology, Université de Mons, 7000 Mons, Belgium
| |
Collapse
|
13
|
Clément G, Loureiro N, Sousa D, Zandvliet A. Perception of Egocentric Distance during Gravitational Changes in Parabolic Flight. PLoS One 2016; 11:e0159422. [PMID: 27463106 PMCID: PMC4963113 DOI: 10.1371/journal.pone.0159422] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2016] [Accepted: 07/01/2016] [Indexed: 12/05/2022] Open
Abstract
We explored the effect of gravity on the perceived representation of the absolute distance of objects to the observers within the range from 1.5-6 m. Experiments were performed on board the CNES Airbus Zero-G during parabolic flights eliciting repeated exposures to short periods of microgravity (0 g), hypergravity (1.8 g), and normal gravity (1 g). Two methods for obtaining estimates of perceived egocentric distance were used: verbal reports and visually directed motion toward a memorized visual target. For the latter method, because normal walking is not possible in 0 g, blindfolded subjects translated toward the visual target by pulling on a rope with their arms. The results showed that distance estimates using both verbal reports and blind pulling were significantly different between normal gravity, microgravity, and hypergravity. Compared to the 1 g measurements, the estimates of perceived distance using blind pulling were shorter for all distances in 1.8 g, whereas in 0 g they were longer for distances up to 4 m and shorter for distances beyond. These findings suggest that gravity plays a role in both the sensorimotor system and the perceptual/cognitive system for estimating egocentric distance.
Collapse
Affiliation(s)
| | - Nuno Loureiro
- Champalimaud Neuroscience Programme, Champalimaud Centre for the Unknown, Lisbon, Portugal
| | - Duarte Sousa
- International Space University, Strasbourg, France
| | - Andre Zandvliet
- European Space Research and Technology Center, European Space Agency, Noordwijk, The Netherlands
| |
Collapse
|
14
|
Perception of Affordance during Short-Term Exposure to Weightlessness in Parabolic Flight. PLoS One 2016; 11:e0153598. [PMID: 27097218 PMCID: PMC4838214 DOI: 10.1371/journal.pone.0153598] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2015] [Accepted: 03/31/2016] [Indexed: 11/19/2022] Open
Abstract
We investigated the role of the visual eye-height (VEH) in the perception of affordance during short-term exposure to weightlessness. Sixteen participants were tested during parabolic flight (0g) and on the ground (1g). Participants looked at a laptop showing a room in which a doorway-like aperture was presented. They were asked to adjust the opening of the virtual doorway until it was perceived to be just wide enough to pass through (i.e., the critical aperture). We manipulated VEH by raising the level of the floor in the visual room by 25 cm. The results showed effects of VEH and of gravity on the perceived critical aperture. When VEH was reduced (i.e., when the floor was raised), the critical aperture diminished, suggesting that widths relative to the body were perceived to be larger. The critical aperture was also lower in 0g, for a given VEH, suggesting that participants perceived apertures to be wider or themselves to be smaller in weightlessness, as compared to normal gravity. However, weightlessness also had an effect on the subjective level of the eyes projected into the visual scene. Thus, setting the critical aperture as a fixed percentage of the subjective visual eye-height remains a viable hypothesis to explain how human observers judge visual scenes in terms of potential for action or “affordances”.
Collapse
|