Supplementary Figure 2: Equivalent ratio as a function of Triple Number in Experiment 1.

Each panel is for one subject. In the choice task, there were 12 different Triples, whose paired Singles were adjusted in width by adaptive procedures (Fig. 2e). For each subject and each Triple, we defined the equivalent width of a Triple as the width of the Single that the subject judged to be as “hittable” as the Triple. We defined the equivalent ratio as the ratio of the equivalent width of the Triple to the total width of its three rectangles. The equivalent ratio provides a measure for the probability density function in subjects’ internal pdf, roughly indicating the mean probability density over the side rectangles of the Triple relative to the probability density around the center. The 12 Triples in the plot are sorted by the horizontal position of the right rectangle in the Triple. Note the measured equivalent ratios (black dots and line) had abrupt changes at adjacent Triples. The U-mix prediction (green line) captured the abrupt changes better than the predictions of the Gaussian prediction (blue line). The predictions of other mixture models (especially mG-mix) were close to that of U-mix and were omitted in the plot for simplicity.