December 2001
Volume 1, Issue 3
Free
Vision Sciences Society Annual Meeting Abstract  |   December 2001
Counter-changing contrast as the basis for the perception of contrast-defined, single-element apparent motion
Author Affiliations
  • Lee A. Gilroy
    Florida Atlantic University, Boca Raton, FL, USA
  • Howard S. Hock
    Florida Atlantic University, Boca Raton, FL, USA
Journal of Vision December 2001, Vol.1, 247. doi:10.1167/1.3.247
  • Views
  • Share
  • Tools
    • Alerts
      ×
      This feature is available to authenticated users only.
      Sign In or Create an Account ×
    • Get Citation

      Lee A. Gilroy, Howard S. Hock; Counter-changing contrast as the basis for the perception of contrast-defined, single-element apparent motion. Journal of Vision 2001;1(3):247. doi: 10.1167/1.3.247.

      Download citation file:


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

      ×
  • Supplements
Abstract

Purpose. Gilroy, Hock, & Harnett (2000) have shown that counter-changing luminance, not Fourier-based, 1st-order motion energy, provides the basis for perceiving luminance-defined, single-element apparent motion (AM). In this study, we investigate AM for contrast-defined (2nd-order) elements. Similar to principles governing luminance-defined AM, contrast-defined AM was expected to depend on events occurring simultaneously at two element locations. When a contrast-defined element is shifted discontinuously between the two locations, the contrast at the first location changes toward the background contrast, while the contrast at the other location changes away from the background contrast (e.g. a homogeneous background has a contrast of 0; a checkered black/white background has a contrast of 1.0). We call this counter-changing contrast. Method. Experiments are based on a pair of small, checkered elements simultaneously visible at two locations. Although the elements' mean luminances remain constant, their contrasts alternate between two values over a series of frames. Results. Combinations of element and background contrasts were selected which showed that the presence of counter-changing contrast is sufficient for the perception of AM. Conclusion. We have shown previously that counter-changing luminance is necessary for the perception of luminance-defined, single-element AM. We now show that counter-changing contrast is necessary for the perception of contrast-defined (2nd-order), single-element AM. These results point to a more general conclusion: AM is perceived when there is a simultaneous change in activation in opposite directions at nearby element locations; i.e. decreasing at one element location and increasing at the other element location.

Gilroy, L.A., Hock, H.S.(2001). Counter-changing contrast as the basis for the perception of contrast-defined, single-element apparent motion [Abstract]. Journal of Vision, 1( 3): 247, 247a, http://journalofvision.org/1/3/247/, doi:10.1167/1.3.247. [CrossRef]
×
×

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.

×