The effect of cartoon-face adaptation on curvature judgment (experiment 1). a , Psychometric functions from a naive subject under the following conditions. 0-c, No adaptation baseline (blue); c-c, adaptation to the most concave curve (green); f-c, adaptation to the saddest face, whose mouth was identical to the most concave curve (red). For each condition, the fraction of convex responses was plotted as a function of the curvature of the test curves. b , Summary of all four subjects' data. For each condition, the average PSE relative to the baseline condition and the SEM were plotted. The p value shown for each condition in the figure was calculated against the baseline condition using the two-tailed paired t test.