Figure 4.
Performance for contrast modulation (CM) stimuli. The stimuli consisted of a contrast-reversing grating (carrier) modulated by a drifting sinewave envelope with a SF of 0.50 cpd and a TF of 3 Hz. The task was to discriminate the direction of motion of the envelope of a CM stimulus presented monocularly at 4.3° of eccentricity. Percent correct responses were measured while varying carrier SF (cpd) within blocks for different values of carrier TF: magenta, 5 Hz; green, 10 Hz; cyan, 15 Hz; and dark blue, 20 Hz. (a–f) Percent correct responses for subjects 1 (S1) through 6 (S6). (g) Mean percent correct responses of the six subjects. Error bars represent the binomial SE of each condition for each subject (a–f) and the SEM (N = 6 subjects) for the subject-averaged results (g).