Abstract
The importance of second-order processing in binocular vision has been documented for a decade. We investigated the dynamical properties of second-order binocular processing as analogous to those of motion processing revealed in motion aftereffects.
We examined possible binocular rivalry in second-order patterns with a static (sSO) or dynamic carrier (dSO). For the carrier, uncorrelated (both between eyes and over time) static or dynamic random dot fields whose contrasts were modulated at 1.5 cpd sinewave with orientations of ±45, ±15, or ±7.5 deg were used. The dominance durations for dSO were about twice as long than those for the comparable first-order luminance gratings at orientations of ±45 and ±15 deg while there was no rivalry at ±7.5 deg. However, for sSO, the perceptual alternations were much slower and hardly perceptible. The perceived depth (tilt) for sSO and dSO at small orientation disparities was measured and about 50% more disparity was needed to match the depth of sSO to that with dSO.
We also investigated possible hysteresis effects in the transition between depth and rivalry for sSO and dSO. A sequence of the sSO or dSO with orientation disparities (0–40 deg) was presented in ascending or descending order. There were substantial hysteresis effects for dSO but the effects were greatly reduced for sSO.
The results suggest that second-order processing in binocular vision and motion have similar dynamical properties. An expansion of current neural models incorporating first-order and delayed second-order visual processing can readily explain our results.
Supported by an NSERC grant to HRW (#OP227224), a CIHR training grant in vision health research and an NSERC postdoctoral fellowship