PSYCHOLOGICAL SCIENCE Research Article MUST FIGURE-GROUND ORGANIZATION PRECEDE OBJECT RECOGNITION? An Assumption in Peril

Abstract-The assumption that figure-ground segmentation ml/st precede object or shape recognition has been celltral to theories ofvisual perception. We showed that assumption to be incorrect in an experiment in whiciz observers reported the first perceivedfigure-ground organization ofbriefly exposed stimuli depicting two regions sharing a figure-ground border. We ma-nipulated the symmetry ofthe two regions and their orientation-dependellt denotivity (roughly, their meaningfulness), and mea-sured how each of these variables influenced figure-ground reports when the stimuli were exposedfor 14, 28, 57, 86, or 100 ms, andfollowed immediately by a mask. Influences onfigure-ground organization from both sym"metry and orientation-dependent object recognition processes were found; both were observed first in the 28-ms condition. Object recognition inputs did not dominate symmetry inputs. We suggest that object rec-ognition processes may operate simultaneously on both sides of edges detected before figure-ground relationships are deter-mined. Figure-ground organization entails segmenting the visual field into regions that are figures and regions that are back-grounds. Figures are patently endowed with shape and appear to occlude backgrounds; the latter appear to be shapeless near the borders they share with figures. Since the early 20th cen-tury, most theories of visual perception and object recognition have been grounded on the assumption that regions must be registered as figures before they can be matched to representa-tions of objects in memory (Biederman, 1987; Hebb, 1949