Abstract
A field of dense random dots that makes a series of small jumps is veridically seen in apparent motion. If the jumps exceed a distance Dmax (Braddick, Vision Res. 1974; Dykmans and Anstis, VSS 2015) the observer loses track of which dot is which and sees only random twinkling motion (dynamic visual noise). Dmax increased steadily with eccentricity, being 0.2° at an eccentricity of 9°, rising to ~3° at an eccentricity of 65°. Thus an orbiting motion that looked like random twinkling in the fovea (jump > small Dmax) could clearly be seen to orbit in the periphery (jump < large Dmax). We have found that if a moving patch (jump < Dmax) was put next to a twinkling patch (jump > Dmax), the motion captured or entrained the twinkle and both patches appeared to move in unison. We used two adjacent rectangular patches, or a moving disk surrounded by a twinkling annulus, or conversely a twinkling disk surrounded by a moving annulus. To avoid motion streaks, the motion was in circular orbits instead of linear. Results: Entrainment increased markedly with increasing eccentricity. In the far periphery (65°), an inner orbiting disc appeared to entrain outward into the surrounding twinkle, its perceived radius increasing by as much as 24%. For the opposite condition, in which an annulus of orbit surrounded twinkle, at 65° an outer annulus of orbit (15% total area) entrained the remaining inner 85% of twinkle.
Meeting abstract presented at VSS 2018