August 2009
Volume 9, Issue 8
Vision Sciences Society Annual Meeting Abstract  |   August 2009
Peripheral sensitivity to biological motion is unaffected by dividing attention
Author Affiliations
  • Gabrielle Roddy
    Department of Psychology, Concordia University, Montreal, QC, Canada
  • Nikolaus Troje
    Department of Psychology, Queen's University, Kingston, ON, Canada
  • Rick Gurnsey
    Department of Psychology, Concordia University, Montreal, QC, Canada
Journal of Vision August 2009, Vol.9, 604. doi:10.1167/9.8.604
  • Views
  • Share
  • Tools
    • Alerts
      This feature is available to authenticated users only.
      Sign In or Create an Account ×
    • Get Citation

      Gabrielle Roddy, Nikolaus Troje, Rick Gurnsey; Peripheral sensitivity to biological motion is unaffected by dividing attention. Journal of Vision 2009;9(8):604. doi: 10.1167/9.8.604.

      Download citation file:

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

  • Supplements

Previous research has shown that stimulus magnification is sufficient to equate sensitivity to biological motion across the visual field. However, this research used point-light walkers with fixed direction differences that make it impossible to judge whether the limits of walker direction discrimination change with eccentricity. We addressed this question by measuring walker direction-discrimination thresholds at a range of sizes from 0° to 16°. We found asymptotic thresholds, at all eccentricities, to be ±1.14 degrees from straight ahead. The psychometric functions at each eccentricity were shifted versions of each other on a log size axis. Therefore, when we divided stimulus size at each eccentricity (E) by an appropriate F = 1 + E/E2 (where E2 is the eccentricity at which stimulus size must double to achieve equivalent-to-foveal performance) all thresholds collapsed onto a single psychometric function. Therefore, stimulus magnification was sufficient to equate sensitivity to walker direction across the visual field. The average E2 value required to achieve this was 1.02. We also examined the role of attention in eccentricity-dependent sensitivity loss using a dual-task procedure in which participants were asked to judge first the colour (red or green) then the direction of the point-light walker. The difficulty of the colour judgment, and hence the level of attentional-engagement, was controlled by maintaining colour contrast at threshold levels. The dual-task returned a single E2 value of 1.20 for walker direction discrimination, suggesting that there is no effect of splitting attention between colour and direction at either fixation or 16°. Although there were no costs of splitting attention in the present study, it may be that such costs would be seen when subjects have to divide attention either between (i) two different spatial aspects of a stimulus or (ii) two different locations.

Roddy, G. Troje, N. Gurnsey, R. (2009). Peripheral sensitivity to biological motion is unaffected by dividing attention [Abstract]. Journal of Vision, 9(8):604, 604a,, doi:10.1167/9.8.604. [CrossRef]
 This research was funded by NSERC grants to Rick Gurnsey.

This PDF is available to Subscribers Only

Sign in or purchase a subscription to access this content. ×

You must be signed into an individual account to use this feature.