The effect of long-term exposure to microgravity on the perception of upright

Abstract

Sensory perception: Knowing which way is ‘up’ Prolonged exposure to microgravity has a long-term effect on the perception of upright. On earth we use visual, body, and gravity cues to help us determine the orientation of ourselves relative to the world which affects many perceptual tasks including reading, recognizing faces, and navigating. Laurence R. Harris and colleagues at York University assessed how seven astronauts who spent 168 days on average on the International Space Station perceived their orientation before, during and after flight. Although no changes were observed during their missions, astronauts’ judgements in the absence of visual cues were worse upon return to earth compared with ground-based controls. Harris and his team found that the effect persisted for up to four months after the astronauts returned to earth. These findings could help develop countermeasures to avoid perceptual mistakes during space travel, and contribute to facilitating safer, long-duration journeys without gravity.