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Martin Voshell, Flip Phillips; Posterior visual space perceptual distortions in ecological applications. Journal of Vision 2002;2(7):514. doi: 10.1167/2.7.514.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: The goal of this research is to extend upon our initial findings (Phillips and Voshell in these proceedings) regarding distortion in the static structure of posterior visual space. Our initial experiments led us to believe that there are perceptual biases in given situations to consistently underestimate and overestimate direction. Continuing upon this vein of external validity in the lab, we immersed observers in more realistic and ecological situations of posterior direction estimation.
Methods: A virtual field was projected onto a screen and artificial pylons were randomly placed in the field. Pylon location varied in depth and lateral positioning. In the first experiment observers were instructed to freely use either shoulder in their pointing task. In the second experiment, observers were instructed to position the automotive mirror as they would in a car and then to proceed with their pointing task using only the mirrored image. In each case, observers made a direction judgment and adjusted a pointing device towards each target.
Results: Results for the bilateral shoulder viewing were consistent across observers. In Experiment I, when the observers had free choice of aim utilizing both shoulders, they consistently overestimated the positions of targets respective to side, and this perceptual spread was hyperbolic in nature. When observers used an automotive rear-view mirror, a consistent shift in object perception was encountered. Observers underestimated ipsilateral stimuli and gradually started overestimating stimuli as more stimuli were presented contralateral to the mirror.
Conclusion: These findings suggest there are inherent distortions in VS that phenomenalogically affect how posterior visual space is perceived. Of a more ecological and applied nature, by taking in regard the distortions both inherent in mirror navigation and non-mirror navigation we may attempt to determine an ideal approach to such activities as backing up in a car.
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