Metacontrast masking between cyclopean and luminance stimuli.

This study investigated the functional equivalence between cyclopean (global stereoscopic) and luminance (local stereoscopic) stimuli. To do so, a metacontrast masking paradigm was employed to determine the level of perceptual interaction between the two stimulus domains. Four target and mask combinations were used: cyclopean target-cyclopean mask, luminance target-luminance mask, cyclopean target-luminance mask, and luminance target-cyclopean mask. Substantial intradomain masking occurred, with the form of masking being similar for both domains. Moreover, significant interdomain masking also occurred, in equal measure for the cyclopean and luminance stimuli, although the magnitude of masking was one-half that of intradomain masking. These results imply that there is a functional equivalence at some stage of the visual system between the mechanisms representing cyclopean and luminance stimuli.