Windy L Roy

Publications (2)4.43 Total impact

• Article: The visual perception of lines on the road.

  Dennis M Shaffer, Andrew B Maynor, Windy L Roy
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  ABSTRACT: The present work demonstrates that observers grossly underestimate the length of lines parallel to their line of sight. In Experiment 1, observers, working from memory, estimated the length of a dashed line on the road to be 0.61 m. This result is consistent with observers' using an average visual angle converted to the physical length of visible lines on the road to estimate their length. In Experiment 2, observers gave verbal and matching estimates that significantly underestimated the length of a 3.05-m line on the ground that was parallel to their line of sight. In Experiment 3, observers significantly underestimated the length of dashed lines on the road while in a moving car. The results of Experiments 1 and 3 are described well by Euclidean geometry, whereas the tangle model that utilizes an increasing function of the visual angle to describe perceived extent best describes the results of Experiment 2.
  Perception & Psychophysics 12/2008; 70(8):1571-80. · 1.37 Impact Factor
• Source

  Available from: osu.edu

  Article: A linear optical trajectory informs the fielder where to run to the side to catch fly balls.

  Dennis M Shaffer, Michael K McBeath, Windy L Roy, Scott M Krauchunas
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  ABSTRACT: P. McLeod, N. Reed, and Z. Dienes (2002) argued that the linear optical trajectory (LOT) strategy incorrectly cues fielders to run forward for balls headed beyond them. The authors of this article explain that the downward optical curvature found for balls landing beyond the fielder's initial position occurs because the balls reorient the direction the fielder is facing during pursuit. Thus, when downward optical curvature begins, the ball is headed to land in front of where the fielder is facing and running. This investigation of open-loop failure conditions has led to new insights such as the reorientation of the fielder, and it supports the use of maintaining matching rates of vertical and lateral optical ball movement consistent with primacy of the LOT control mechanism even when interception is unachievable.
  Journal of Experimental Psychology Human Perception & Performance 01/2004; 29(6):1244-50. · 3.06 Impact Factor