Perception & Psychophysics

, Volume 28, Issue 1, pp 19-27

First online:

Dynamic visual noise and the stereophenomenon: Interocular time delays, depth, and coherent velocities

  • David S. FalkAffiliated withDepartment of Physics and Astronomy, University of Maryland
  • , Robert WilliamsAffiliated withBrain and Perception Laboratory, Bristol University


This study concerns the stereophenomenon obtained with binocular viewing of dynamic visual noise with a neutral density filter over one eye. Such a display offers the opportunity to study quantitatively the way in which perceptions are organized when the stimulus provides virtually no organization. Measurements are reported of interocular delay times, apparent depth, and horizontal streaming velocity. The effects of changes in filter density, viewing distance, and dot rate are discussed within the context of various theoretical models that have been proposed. These models attribute the stereophenomenon to temporal disparity, the Pulfrich effect, and random spatial disparity. None is shown to account fully for all aspects of the phenomenon. Finally, the effects of tracking are explained as a property of dynamic visual noise.