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Suppression periods of rivalry are accompanied by a general loss in visual sensitivity. Thus, a probe target superimposed on a stimulus engaged in rivalry is more difficult to detect when that probe is presented while the rival target is suppressed, compared to detection performance when the same probe is presented during rival target dominance (Wales and Fox, 1970; Fukuda, 1981; O'Shea and Crassini, 1981; Smith et al, 1982).
Use the animation sequence below to experience this effect for
yourself. The "probe" consists of a small circular patch
of grating that briefly appears in the upper left-hand portion
of the grating whose bars are oriented diagonally clockwise --
the upper figure (one frame from the animation) shows the location
of the probe. When you play the animation, the probe fades "on"
and then fades "off" quickly. Initiate a few probe presentations
when the rival target upon which the probe appears is dominant,
noticing how it can barely be detected; if you have trouble seeing
the probe, try looking directly at the location where it appears,
not at the central fixation mark. Next initiate presentations
when that grating is completely suppressed (meaning that the diagonal
counterclockwise grating is dominant exclusively). Notice how
the probe is now impossible to see. Quantitative measures show
this loss in visual sensitivity to be on the order of 0.3 - 0.5
log units.
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References
Fukuda, H., 1981: Magnitude of suppression of binocular rivalry
within the invisible pattern, Percept. Mot. Skills 53, 371-375.
O'Shea, R.P. and Crassini, B., 1981: The sensitivity of binocular
rivalry suppression to changes in orientation assessed by reaction-time
and forced-choice techniques, Perception 10, 283-293.
Smith, E.L., Levi, D.M., Harwerth, R.S. and White, J.M., 1982:
Color vision is altered during the suppression phase of binocular
rivalry, Science 218, 802-804.
Wales, R. and Fox, R. 1970: Increment detection thresholds during
binocular rivalry suppression, Percept. Psychophys. 8, 90-94.