Figure 2.

Psychophysical matching task. A–C, Estimated flicker intensity (% opacity of the sinusoidally modulated gray field superimposed at the center of the reference stimulus) for different spatial frequencies of the test pattern (i.e., different number of spokes within the wheel) (A), different contrast levels (B), and right-monocular (R), left-monocular (L), and binocular (B) viewing conditions (using a stimulus with 32 spoke sectors and 100% contrast) (C). p values are obtained from one-way ANOVAs. n.s., Not significant. D, Distribution of estimated frequencies of the perceived illusory flicker over trials. We analyzed for each subject (N = 9) and experimental condition with optimal flicker perception (32 spoke wheel and 100% contrast level) the three trials with strongest flicker intensity. A–C, Error bars indicate SEM.