Einfluss gravizentrischer, egozentrischer und visueller Reize auf die räumliche Orientierung des Menschen: Die Wahrnehmung der habituell subjektiven Vertikalen

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The perception of “up” and “down” constitutes an important aspect of spatial orientation and makes use of the three reference frames: direction of gravity (gravicentric); the orientation of visual objects (allocentric), e.g. walls or trees; and the orientation of our own body (egocentric), e.g. the long body axis. Usually, the three reference frames are aligned, so that humans have an unambiguous perception of “up” and “down”.
Previous studies about spatial orientation have investigated how a dissociation between these reference frames affects the perception of verticality. However, many of these studies have limited ecological validity, as participants are explicitly instructed to use a specific reference frame (for example the direction of gravity).
The experimental design of the present work was based on few studies in which the experimenters deliberately avoided any specific instructions regarding reference frames, so that participants would use their individual comprehension of “up” and “down” – what we call the “habitual subjective vertical”. Beside the validation of the habitual subjective vertical (study I), we also focused on the investigation of the differences between the use of the habitual subjective vertical in perception and action tasks (study I – III). Furthermore, we aimed to decode the weightings of all three contributing reference frames (studies IV and V).
In contrast to the findings of studies using pre-defined reference frames, the current results (study I) show significantly different characteristics – a bimodal distribution (responses close to the correct alignment of the gravicentric or egocentric verticals). The comparison of the perceptual and motor tasks revealed inconsistent responses between the current studies. Nevertheless, based on the intra- and inter-individual differences we assumed that there were distinct habitual subjective verticals between perception and action tasks (studies I – III). This was likely due to the additional gravicentric cues available in the action tasks. In studies IV and V, we decoded the weighting of the reference frames contributing to the habitual motor vertical. Our results show that visual cues have only a minor influence on the habitual motor vertical.
Overall, the diverging intra- and inter-individual responses on the current tasks support the existence of a habitual subjective vertical. The alignment of which is contingent upon diverse factors. This percept can vary in terms of the relative weightings of the three contributing reference frames, as a function of body postures, instructions, task demands and other factors.
Original languageGerman
Place of PublicationKöln
PublisherDeutsche Sporthochschule Köln
Number of pages118
Publication statusPublished - 2017

ID: 3195169

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