August 2014
Volume 14, Issue 10
Vision Sciences Society Annual Meeting Abstract  |   August 2014
Perceived Occlusion Velocity for Fully Visible and Fragmented Shapes
Author Affiliations
  • Ricarda Moses
    University of Kaiserslautern, Germany
  • Tandra Ghose
    University of Kaiserslautern, Germany
  • Gennady Erlikhman
    Department of Psychology, University of California, Los Angeles, USA
  • Philip J. Kellman
    Department of Psychology, University of California, Los Angeles, USA
Journal of Vision August 2014, Vol.14, 249. doi:
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      Ricarda Moses, Tandra Ghose, Gennady Erlikhman, Philip J. Kellman; Perceived Occlusion Velocity for Fully Visible and Fragmented Shapes. Journal of Vision 2014;14(10):249.

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

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Background: In order to perceive coherent perceptual units, the visual system must integrate information about fragments across space and time (Palmer, Kellman & Shipley, 2006). This requires the accurate encoding of fragment velocity when they are visible and occluded. However, previous research has shown that the representation of occlusion velocity is often not veridical (DeValois & Takeuchi, 2001; Palmer & Kellman, 2013). Questions: Is perceived occlusion velocity similar for shapes that are fully visible ("Full"), spatially fragmented, or spatiotemporally fragmented? Is the misperception (if any) dependent on the duration of occlusion? Does perceived occlusion velocity depend on eye-movement patterns or vice versa? Method: In the "Full" display a red, textured oval traveled in front of two white rectangles separated by a black rectangle (occluder). The oval was invisible when it passed behind the occluder. In the spatially fragmented condition, a horizontal black bar spanning the width of the screen separated the oval into two pieces. In the spatiotemporally condition, only top or bottom half of the oval was visible on either side of the occluder. The task was to report whether the oval emerged from occlusion sooner or later than anticipated, given its constant velocity. The time that the oval was occluded was manipulated by using short, medium, or long occluder width. The perceived occlusion-velocity was calculated from the 50% point of the resulting psychometric functions. Eye-movements were also recorded. Results and Conclusions: Perceived occlusion-velocity did not differ for whole and fragmented shapes, but varied with occluder width. Remarkably, perception of occlusion velocity was not predicted by patterns of eye movements. We discuss the results in relation to previous work on occlusion velocity with differing ranges of speed and aperture separation.

Meeting abstract presented at VSS 2014


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