A previous finding (Weitzman, 1963) suggested the possibility that division of the perceptual field into figure and ground regions results in a threshold difference between figure and ground contours. To examine this possibility discrimination thresholds for 2 lines were determined, in tachistoscopic presentation, for 29 college students and student nurse Ss [subjects]. Fixation was central between the lines, one of which was contained in a figural region, and the other in a ground region. Retinal equivalence of the 2 lines was indexed by an interpolated task. The prediction that the figural contour would have a lower discrimination threshold than the ground contour was supported, at the .05 level, by the results. The finding was interpreted as requiring that the possibility of modification of stimulus input, as a result of the dichotomizing of stimuli into figure and ground regions, be included in any complete description of contour perception.