of range voltages (±75 μV) were rejected as artifacts and were excluded from further processing. If 50% or more of the epochs of a participant contained artifacts, this participant was excluded from further analyses. As a result, three participants were rejected from further analyses, two in the placebo group and one in the alcohol group. The mean number of included negative feedback trials was 25.02 (SE = 0.75), and mean number of positive feedback trials was 29.38 (SE = 0.60). Epochs locked to positive and negative feedback were averaged separately for artifact-free trials at each scalp site, producing one average waveform per feedback condition per subject. All epochs, across balloons in the entire test block from the start of the procedure, were included in the average. A finer grain analysis of the data separated across the three 20-trial blocks of the BART (as was done for the behavioral measure of risk-taking) was not appropriate because this resulted in too few epochs for each average.
