Determination of visual figure and ground in dynamically deforming shapes

Elan Barenholtz, Jacob Feldman
2006 Cognition  
Figure/ ground assignment -determining which part of the visual image is foreground and which background -is a critical step in early visual analysis, upon which much later processing depends. Previous research on the assignment of figure and ground to opposing sides of a contour has almost exclusively involved static geometric factors -such as convexity, symmetry, and size -in non-moving images. Here, we introduce a new class of cue to figural assignment based on the motion of dynamically
more » ... ming contours. Subjects viewing an animated, deforming shape tended to assign figure and ground so that articulating curvature extrema -i.e., "hinging" vertices -had negative (concave) contour curvature. This articulating-concavity bias is present when all known static cues to figure/ground are absent or neutral in each of the individual frames of the animation, and even seems to override a number of well-known static cues when they are in opposition to the motion cue. We propose that the phenomenon reflects the visual system's inbuilt expectations about the way shapes will deform -specifically, that deformations tend to involve rigid parts articulating at concavities.
doi:10.1016/j.cognition.2005.12.002 pmid:16448640 fatcat:qj2xheeyy5bazevp7mfad3d7lm