Abstract
Van Lier, Vergeer, and Anstis (2009) reported that color information in a visual afterimage could spread across regions that were not colored in the inducing stimulus. The perceived color and shape of the afterimage could be manipulated by drawn contours that apparently trapped the spread of afterimage color signals. New simulations of the BCS/FCS model of visual perception (Grossberg & Mingolla, 1985a,b) demonstrates that the model easily accounts for many of the properties of these afterimages. A core idea of the model is that representations of colors spread in all directions at a filling-in stage until blocked by boundary signals. Boundary signals that form closed connected contours can trap the spreading colors to create a surface of relatively uniform color. A side effect of this process is that color contrasts that are too weak to form boundaries may spread beyond their physical location. The weak color contrasts that are often present with an afterimage are one example of this phenomenon. The model simulations further predict that a small closed contour should block the spread of afterimage color into the interior of the contour. Empirical data demonstrate the validity of this prediction.