ERP waveforms were filtered at 0.03–16.0 Hz and the P3 amplitude was measured as the voltage difference from the pre-stimulus baseline window (0–100 ms) to the largest positive going peak within the post-stimulus time window (275–600 ms) after the onset of an outcome stimulus. A semi-automatic computerized algorithm developed in our laboratory identified the P3 peak as a time point on the P3 wave with maximum amplitude within the 275–600 ms post-stimulus time window (Cohen et al., 2002; Kamarajan et al., 2009). Further, ERP waveforms were visually analyzed for the correctness of peak identification and morphology of the waveforms. Since the P3 topography for smaller and larger amounts (10¢ and 50¢) were similar (Kamarajan et al., 2009; Kamarajan et al., 2010), trials for the two amounts (10¢ and 50¢) were combined for the loss condition (loss 10¢ + loss 50¢) as well as for the gain condition (gain 10¢ + gain 50¢) in order to have more trials per subject and more subjects per group. Mean trial numbers across the risk groups in each condition are: LR = 39.12 and
