Sex differences in judging self-orientation: the morphological horizon and body pitch.
BACKGROUND
Sex differences exist for many spatial tasks. This is true for circular vection, field dependence, and perception of veridical vertical with body tilt. However, explanations for these sex differences is lacking in the literature. In this study, we investigated the nature of individual differences in the perception of self-orientation in humans. Male and female participants were asked to identify their Morphological Horizon (i.e., line perpendicular to saggital plane at eye-level) in different body orientations relative to gravity (i.e., 45 deg and 135 deg body pitch) with and without prior whole body rotation.


RESULTS
Sex explained the observed differences in the perception of self-orientation only when blood distribution was least altered (i.e., 45 deg body pitch) and without prior whole body rotation. Specifically, females presented a more footward bias than males in these conditions.


CONCLUSIONS
These results add to the literature on sex differences for spatial orientation tasks. As the differences were only observed with static conditions and when blood distribution was least affected, we concluded that sex differences in the perception of self-orientation are associated with gravireceptors (e.g., otoliths).
Tremblay
Luc
L
University of Toronto, 55 Harbord Street, Toronto, Ontario, M5S 2W6, Canada. luc.tremblay@utoronto.ca
Elliott
Digby
D
D000328:Adult; D005260:Female; D006112:Gravitation; D018594:Human Body; D006801:Humans; D008297:Male; D009949:Orientation / Q000502:physiology*; D011187:Posture / Q000502:physiology*; D012649:Self Concept; D012727:Sex Characteristics; D013028:Space Perception / Q000502:physiology*; D013223:Statistics as Topic