Sex differences and the Perception of Upright under different Gravity loads – implications for spaceflight

Under normal terrestrial conditions, people are always aware of their orientation in space. The decision where "up" is happens as if by itself. The same applies to the perception "vertical" and "horizontal". But a closer look at perception reveals a very complex process. The perception of "up, vertical, and horizontal" is influenced by a variety of different stimuli, such as the type of display (visual stimuli), the orientation of a body in space (idiotropic stimuli), and gravity, which confirms to everyone under normal conditions where "up" and "down" are and thus what should be evaluated as "vertical" and "horizontal." These cue stimuli seem to be used differently by men and women, but this does not make any difference in normal circumstances, because usually these sensory stimuli are in agreement with each other. However, in unusual environments, such as underwater or in outer space, these sensory stimuli may conflict or individual stimuli may be absent altogether. If these sensory impressions become ambiguous, they can deceive the perceiver and lead to a false perception of body orientation, which may be different for men and women. The person then no longer knows for sure where above and what is "vertical," which can result in fatal errors. Reports of diving and space accidents are replete with examples where divers and pilots have become disoriented, resulting in sometimes fatal accidents (Previc & Ercoline, 2004). There are also other applications in the field of aviation research, particularly in perception from "above" during complex flight maneuvers such as high speed turns and the like. In addition, there are individuals whose ability to use gravity as a source of perceptual information is already limited/unreliable even under normal terrestrial conditions, as is more common among the elderly or disabled. The knowledge gathered by the experiments should help us to predict how the perception of "upright" (or perceptual upright, PU - the perception of "upright") as well as the perception of "vertical" (or perceptual vertical) changes in men and women in situations where gravity is not a reliable source of orientation perception. This is the case, for example, on the Moon, where gravity has a smaller strength than on Earth (about 0.2g). Although research in this area has been active for years (e.g., Mittelstaedt, 1983; Oman et al., 2003; Adams et al., 2004; Jenkin et al., 2004; Dyde et al., 2006), human orientation perception is not yet fully decoded and predictable, especially in special environments such as underwater, on the Moon, or in zero gravity. Many of the errors that occur when working in space are consequences of perceptual misinterpretations, some of which are related to the issues to be investigated here. Thus, the goal of our project is to make perception predictable and thus to be able to help female and male individuals (pilots, astronauts, divers) to perceive their environment in an optimal way, each depending on the particular circumstances of their environment and their gender. The results of our research project should help us to develop a better understanding of how people (men and women) decide where "up" is and where "vertical" is. Predecessor studies PUG1-3 registered in DRKS with the number: 00029681