FIGURE 2.

GLM results for response bias and accuracy. (a) Amplitude spectrum of accuracy: The amplitudes were computed with the beta coefficients obtained from the GLM which was fitted to the responses collapsed across the two target‐probability conditions, L80 and R80. This analysis includes all trials on which a frequent or infrequent target was presented. The orange line shows the mean vector length of the individual subject vectors (N = 17) at every frequency from 4 to 12 in 0.1‐Hz steps. The orange‐shaded area around the line indicates the dispersion of the individual subject vectors for the same frequencies and shows ±1 standard error of the mean (SEM). (b) Results of 2D permutation test for accuracy: The orange solid line shows the p‐values yielded by the 2D permutation test, corrected for multiple comparisons (see Methods). The uncorrected p‐values are shown by the orange dotted line. The red line indicates α = 0.05. No frequency survived the strict multiple comparison correction we applied. (c) Amplitude spectrum of response bias: As in (a), we collapsed responses across the L80 and R80 conditions. The green line shows the mean vector length of the individual response bias vectors with the shaded area around indicating the vectors’ dispersion in ±1 SEM. There is a one clear peak in the amplitude spectrum around 9.1 Hz. (d) Results of the 2D permutation test for response bias. Only the frequencies around 9.1 Hz remain significant after the correction. (e) Response bias vectors at 9.1 Hz for individual subjects. (f) Illustration of the 2D permutation test, corrected for multiple comparisons. Each green dot represents the maximal mean vector across all tested frequencies (frequency changes for the individual dots), obtained by permuting the individual response data. The red dot indicates the maximal mean vector of the original group data at 9.1 Hz. The p‐value reflects the proportion of permuted vectors equal or exceeding the original mean vector (i.e., all the green dots that fall outside the red circle)