Table 1.

Initial contrasts of the above- and below-convergence variations of the 2AFC 1 up/1 down staircases for Experiment 1. Notes: The contrasts were equal between reddish (R) and greenish (G) and between bluish (B) and yellowish (Y) conditions but varied among the three spatial patterns (gratings, Gabors, and Gaussians). All values are given in terms of their appropriate mechanism contrast.

Stimulus	Grating			Gabor			Gaussian
Color	R/G	B/Y	DG	R/G	B/Y	DG	R/G	B/Y	DG
Initial above-convergence contrast (mechanism contrast)	0.068	0.51	0.25	0.068	0.51	0.18	0.027	0.29	0.18
Initial below-convergence contrast (mechanism contrast)	0.034	0.35	0.09	0.034	0.35	0.09	0.008	0.10	0.09