Group mean proportions of question judgments as a function of the F0 increments in the cooperating vs. conflicting conditions. Panels (a) through (d) display the data for the CI group, the NH group under the full-spectrum condition, the NH group under the 8-channel condition, and the NH group under the 4-channel condition, respectively. The x-axis in each panel indicates the steps of F0 contour increments; the y-axis indicates the proportions of question judgments. Data points in the cooperating and conflicting conditions are linked with solid and dashed lines, respectively.