Intermediate stimulus comparisons
To ensure that the found correlation was not an artifact of the extracted thresholds, Samaha & Postle also conducted tests with the proportion of correct responses on the intermediate stimulus onset asynchrony (30 ms gap). We replicated this analysis, and found a moderate correlation between the proportion correct and peak alpha frequency from eyes-closed EEG-recording (r = 0.33, P < 0.05, one-tailed). We found no statistically significant correlation for peak alpha frequency extracted from electrode B7 for pre-stimulus EEG-recording (r = 0.28, P = 0.07, one-tailed).