Microgenesis of surface completion in visual objects: Evidence for filling-out

Using metacontrast masking we examined the temporal dynamics of surface completion in object vision. By varying the stimulus onset asynchrony between the target object and the flanking mask(s), we obtained estimates of the time required for the entire surface contrast to fill out within the area delimited by the contours/edges of the target. The estimated speed of the filling-out process was 36.0 deg/s. Using existing estimates of cortical magnification, the computed filling-out speed in terms of cortical distance is .385 m/s, a value that approximates the estimated cortical filling-in speed and the speed of horizontal propagation in monkey V1. We discuss our results in relation to (1) prior findings of filling-in and filling-out phenomena, using surface completion in cortical space as the unifying principle, and (2) extant computational models of object vision.

► Previous research has demonstrated surface filling-in; here we show surface filling-out.
► Filling-out may be a sequential filling-in proceeding along coarse-to-fine spatial scales.
► Both filling-out and filling-in appear to occur at similar constant speeds in cortical space.