Fig. 1.

Stimuli and masks used in (a) Experiment 1 and (b) Experiment 3. For each experiment, an example stimulus is shown on the left, and a continuous flash suppression (CFS) mask is shown on the right. Experiment 1 utilized the simultaneous brightness contrast illusion. The suppressed eye was shown two gray circles that were physically identical but appeared different in luminance because of the context. The CFS mask covered most of the illusion stimulus except for two “holes” (highlighted here by arrows) that coincided with the two gray circles. Experiment 3 utilized the Kanizsa triangle illusion. The suppressed eye was shown four inducer elements, three of which created the illusory impression of a triangle. In the selective-mask condition (illustrated here), four circular CFS masks covered the inducers in the illusion stimulus; in the invisible condition, a single CFS mask covered the entire stimulus.