Comparison of monoptic and dichoptic masking by light

Abstract

Observers detected drifting gratings presented on a steady uniform field or on a background of uniform flicker with the same time-averaged luminance. Masking effects were obtained whether the flicker mask was presented to the eye on the same side as the test grating or to the one on the opposite side. Unlike masking-by-light studies, in which the mask changes the mean luminance of the display, dichoptic effects were only slightly smaller than those obtained monoptically. Moreover, when observers detected flicker masked by gratings, the dichoptic effect was as large as or larger than the monoptic masking. These results are consistent with the view that masking by light involves separate steady-state luminance and transient components. It is likely that only the transient effect occurs under conditions of dichoptic stimulation. © 1984 Psychonomic Society, Inc.