Abstract
Introduction:
On Earth, spatial orientation is defined by vector model of three reference frames: the direction of gravity; the visual surround and the orientation of the own body`s longitudinal axis. The absence or the incongruence of these reference frames during spaceflight might challenge astronauts’ spatial orientation and thus lead to performance errors, to the detriment of the mission’s success. The purpose of the study was to investigate spatial orientation in weightlessness as it manifests not in perception but rather in motor performance. Additionally, we compared the data to prone body posture on Earth, so that gravity pulled orthogonally to the body / task. In more detail, subjects are asked to flip a series of switches into the "off" position.
Methods:
Twenty-one participants (10 female; 28.5 ± 3.8 years) were tested in two conditions (in parabolic flight and on Earth). Both conditions were characterized by a lack of meaningful gravitational cue, also on Earth, since participants lay prone. The visual surroundings were occluded. Participants were asked to flip an omnidirectional switch “down” in order to turn a visual stimulus off. The experimenter avoided any definition of “down”, i.e., participants were not told to move the switch in the direction of the own long body axis / other body parts, or of the additional visual cues. The cues about their visual vertical (labeling) were congruent / dissociated from the egocentric vertical, or totally absent.
Results:
When egocentric and visual reference frames coincided, results revealed no significant difference between the conditions – responses showed only a slight clockwise shift from the vertical. If visual reference frame was absent, the subjective vertical was also egocentric-orientated – slightly more clockwise. Results of dissociated reference frames showed a significant difference to the congruent reference frames. Overall, there were no differences between the conditions.
Conclusion:
We conclude that the vector model for the subjective perceptual vertical could also be applicable for the subjective motor vertical. Based on the similarity of responses, one might argue that experiments could be done in prone body posture on Earth. However, it could be proved that all participants tried first to push the switch ‘down’ in direction of gravity (on Earth), which indicates that their spatial orientation was not re-orientated. This still indicates a difference between spatial orientation in weightlessness and on Earth.
Supported by the German Ministry for Economic Affairs and Energy (50WB1425)
On Earth, spatial orientation is defined by vector model of three reference frames: the direction of gravity; the visual surround and the orientation of the own body`s longitudinal axis. The absence or the incongruence of these reference frames during spaceflight might challenge astronauts’ spatial orientation and thus lead to performance errors, to the detriment of the mission’s success. The purpose of the study was to investigate spatial orientation in weightlessness as it manifests not in perception but rather in motor performance. Additionally, we compared the data to prone body posture on Earth, so that gravity pulled orthogonally to the body / task. In more detail, subjects are asked to flip a series of switches into the "off" position.
Methods:
Twenty-one participants (10 female; 28.5 ± 3.8 years) were tested in two conditions (in parabolic flight and on Earth). Both conditions were characterized by a lack of meaningful gravitational cue, also on Earth, since participants lay prone. The visual surroundings were occluded. Participants were asked to flip an omnidirectional switch “down” in order to turn a visual stimulus off. The experimenter avoided any definition of “down”, i.e., participants were not told to move the switch in the direction of the own long body axis / other body parts, or of the additional visual cues. The cues about their visual vertical (labeling) were congruent / dissociated from the egocentric vertical, or totally absent.
Results:
When egocentric and visual reference frames coincided, results revealed no significant difference between the conditions – responses showed only a slight clockwise shift from the vertical. If visual reference frame was absent, the subjective vertical was also egocentric-orientated – slightly more clockwise. Results of dissociated reference frames showed a significant difference to the congruent reference frames. Overall, there were no differences between the conditions.
Conclusion:
We conclude that the vector model for the subjective perceptual vertical could also be applicable for the subjective motor vertical. Based on the similarity of responses, one might argue that experiments could be done in prone body posture on Earth. However, it could be proved that all participants tried first to push the switch ‘down’ in direction of gravity (on Earth), which indicates that their spatial orientation was not re-orientated. This still indicates a difference between spatial orientation in weightlessness and on Earth.
Supported by the German Ministry for Economic Affairs and Energy (50WB1425)
| Originalsprache | Deutsch |
|---|---|
| Titel | Human Physiology Workshop : 9th of December 2017 |
| Seitenumfang | 1 |
| Herausgeber (Verlag) | Deutsches Zentrum für Luft- und Raumfahrt e. V. (DLR) |
| Erscheinungsdatum | 2017 |
| Seiten | 11 |
| Publikationsstatus | Veröffentlicht - 2017 |
| Veranstaltung | German Human Physiology Workshop 2017 - Köln, Deutschland Dauer: 09.12.2017 → 09.12.2017 Konferenznummer: 2 |