“…By comparison, object surfaces and support structures, such as the background, typically comprise regions where these properties vary more slowly. Not surprisingly, the processing of both image discontinuities and the grouping of features over space have featured prominently in models of image segmentation (Grossberg & Mingolla, 1985; Koechlin, Anton, & Burnod, 1999; Li, 2000; Malik & Perona, 1990; Roelfsema, Lamme, Spekreijse, & Bosch, 2002; Thielscher & Neumann, 2003) and in empirical studies (Bach & Meigen, 1992; Lamme, Van Dijk, & Spekreijse, 1992; Landy & Bergen, 1991; Marcus & Van Essen, 2002; Nothdurft, 1991; Song & Baker, 2006; Sutter & Graham, 1995). …”