Figure and ground in space and time: 1. Temporal response surfaces of perceptual organization.
The figure-ground organization of an ambiguous bipartite pattern can be manipulated by altering the temporal-frequency content of the two regions of the pattern. Ambiguous patterns in which the two regions of each pattern contained sine-wave gratings of either 8, 4, 1, or 0.5 cycles deg-1 undergoing contrast reversal at rates of 0, 3.75, 7.5, or 15 Hz were tested for figure-ground organization under conditions of equated space-averaged and time-averaged luminance and perceived contrast. All combinations of temporal-frequency differences between the two regions were tested at each spatial frequency. The data are reported for two levels of temporal resolution (15 and 30 s). The pattern region with the relatively higher temporal frequency tended to be seen as the background a higher percentage of the viewing time. There were significant linear trends for the appearance as background of the region of higher temporal frequency with respect to the magnitude of the temporal-frequency difference between the two regions of each pattern for all spatial frequencies and data intervals except the final 15 s interval of the lowest (0.5 cycle deg-1) spatial-frequency condition.
Klymenko
V
V
Department of Radiology, University of North Carolina, Chapel Hill 27514.
Weisstein
N
N
D005556:Form Perception; D006801:Humans; D009039:Motion Perception; D010364:Pattern Recognition, Visual; D010775:Photic Stimulation; D013997:Time Factors