August 2012
Volume 12, Issue 9
Vision Sciences Society Annual Meeting Abstract  |   August 2012
Effects of environment constraints and judgments about action on distance judgments
Author Affiliations
  • David Lessard
    Department of Psychology, University of Utah
  • Sarah Creem-Regehr
    Department of Psychology, University of Utah
  • Jeanine Stefanucci
    Department of Psychology, University of Utah
Journal of Vision August 2012, Vol.12, 1092. doi:
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      David Lessard, Sarah Creem-Regehr, Jeanine Stefanucci; Effects of environment constraints and judgments about action on distance judgments. Journal of Vision 2012;12(9):1092. doi:

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      © ARVO (1962-2015); The Authors (2016-present)

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To determine action capabilities, an actor must compare environmental features to the actor’s individual body and capabilities (Gibson, 1979). Previous research, such as Witt et al. (2005), has shown that changing an actor’s ability to reach by changing the body influences judgments of distance to reachable objects. However, it is unclear whether environmental features that could affect reaching will also alter estimates of distance. The current studies tested whether environmental features that constrain reaching would influence estimated distance to reachable objects. In Experiment 1, participants judged distances to a small object when it was behind a clear, reach-limiting Plexiglas barrier and also when the barrier was absent. Participants estimated their ability to reach the object (yes or no response), and then visually matched the perceived distance to the object. For analysis, we created ratios that divided distance judgments by the actual distance to the object. The results indicated a main effect for the presence of the barrier, such that participants judged the distance to the object as farther when the object was behind the barrier than when the barrier was absent. The barrier did not significantly affect reachability judgments. Experiment 2 investigated whether intent to reach is necessary to induce the effect of the barrier. Participants performed the distance-matching task but did not give estimates of their ability to reach the object; reaching was not mentioned. Experiment 2 did not result in a significant difference for distance judgments when the barrier was present versus absent. These results suggest that environmental features that constrain action can influence distance estimations but only when the actor is thinking about performing a distance-relevant action. Further experimentation is in progress to test whether accounts of motor simulation or task expectations may explain these effects.

Meeting abstract presented at VSS 2012


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