The perceptual consequences of these asymmetric roles played by positive and negative curvature in part segmentation have been demonstrated in a number of contexts, including figure-ground perception (Baylis & Driver,
1995b; Driver & Baylis,
1996; Hoffman & Singh,
1997), amodal completion (Liu, Jacobs, & Basri,
1999), memory for shapes (Braunstein, Hoffman, & Saidpour,
1989), the perception of symmetry and repetition in visual patterns (Baylis & Driver,
1994,
1995a), the localization of vertex height (Bertamini,
2001), the perception of transparency (Singh & Hoffman,
1998), and visual search (Wolfe & Bennett,
1997; Hulleman, te Winkel, & Boselie,
2000; Xu & Singh,
2002). Moreover, a number of recent studies have demonstrated that selective attention can be allocated to individual parts (Barenholtz & Feldman,
2003; Vecera, Behrmann, & Filapek,
2001; Vecera, Behrmann, & McGoldrick,
2000; Watson & Kramer,
1999). In particular, visual comparisons are found to be systematically faster and more accurate when they involve features of a single part of an object, rather than features found on two distinct parts—even when the curvature profile of the intervening contour is carefully controlled (Barenholtz & Feldman,
2003).