Figure 2.

Individual d′s in the three regions, showing their sensitivity to the stimulus statistics. A, B, Performance (d′) of Controls (A; N = 14) and Dyslexics (B; N = 14) in Bias+, Bias0, and Bias− trials. Thick lines denote medians. Thin lines denote individual performance. C, Difference between Bias+ d′ and Bias− d′for each participant (Controls in blue and Dyslexics in red). In both groups, performance in the Bias+ regions was generally better than in the Bias− region (d′ of Bias+ > d′ of Bias0 > d′ of Bias−; Friedman tests, Controls: p < 0.00005; Dyslexics: p < 0.005). But Controls were more sensitive to the prior distribution than Dyslexics (Group × Condition interaction; Mann–Whitney test for interaction of Bias+ vs Bias− and Controls vs Dyslexics, z = 3.5, p < 0.001).