Thirty six electrodes, as indicated in Figure 3, were grouped in to 6 scalp regions for the statistical analyses. The ERP data were analyzed by performing a linear mixed model of the Analysis of Variance (ANOVA) using the Statistical Analysis System (SAS, version 9.2) (SAS Institute Inc., NC 27513, USA). The application of mixed effects model of the Analysis of Variance (ANOVA) in our study is due to its several advantages over the traditional methods of ANOVA (Gueorguieva and Krystal, 2004), and has been successfully implemented by researchers to analyze EEG data (Bachman et al., 2008). The covariance structure used in the model was ‘Compound Symmetry’ which has a constant variance and constant covariance. The model included five factors as fixed effects: Valence (loss, gain), Amount (50¢, 10¢), Region (frontal, central, parietal, occipital, left-temporal, and right-temporal), Electrode (6 electrodes) as within-subjects factors, and Group (control, alcoholic) as a between-subjects factor. In order to keep the number of electrodes equal across each region, only 6 electrodes from each region were selected (as some regions had only 6 electrodes). We treated electrodes
