Rapid Integration of Contour Fragments: From Simple Filling-in to Parts-based Shape Description

Brain potentials and integration of external and internal features into face representations

“…One possibility is that external features are quite useful for triggering the neural mechanisms responsible for the detection of perceptual input specifying the stimulus as a face (processing of "first-order relations" in Maurer et al, 2002). This idea is not so surprising, since facial contours have been found to be significant in the initial stages of development of face processing skills (Mondloch et al, 1999;Mondloch et al, 2002;Pascalis et al, 1995;Simion et al, 2001), and contours in general, have shown themselves to be crucial for shape perception in objects (Breitmeyer et al, 2006;De Winter and Wagemans, 2003;Lamote and Wagemans, 1999;Seghier and Vuilleumier, 2006;Strother and Kubovy, 2006).…”

“…External features may also be relevant when new face representations are being constructed (Sergent, 1986) and face processing skills are developing (Mondloch et al, 1999;Mondloch et al, 2002;Pascalis et al, 1995;Simion et al, 2001). The relevance of contours is revealed in several experiments on shape perception (Breitmeyer et al, 2006;De Winter and Wagemans, 2003;Lamote and Wagemans, 1999;Seghier and Vuilleumier, 2006;Strother and Kubovy, 2006) and supported by the existence of neurons in the visual cortex responding to them (Peterhans and von der Heydt, 1991).…”

Processing convexity and concavity along a 2-D contour: figure–ground, structural shape, and attention

“…In their Experiment 3, participants were asked to mark apparent part boundaries: 81 % of participants marked part boundaries indicating minima parts, 10 % indicating maxima parts, and 9 % other positions. Another study that attempted to test the minima rule was by Lamote and Wagemans (1999). They used closed contours and found that convex (M+) deletions were easier to detect than the deletions around the other two singularities (m− and inflections).…”

Perceptually relevant and piecewise linear matching of silhouettes

“…The sharpness of cusps has also been exploited in attempts to quantify the salience of SB segments, for the recognition and similarity-based retrieval of SBs [10,13]. Recently, the above observations, regarding the increased salience of cusps relative to inflection points and the correspondence of this salience to the sharpness of a cusp, have been verified through psychophysical experiments [14][15][16].…”