consistent with the parallel correlations based on the twins as individuals (−0.18 to −0.21). Correlations of intrapair differences in alcohol use with intrapair differences in P3 offer some within-family control for many unmeasured between-family confounds, including family history and parental alcohol use, confounds that could mediate any association between drinking patterns of young adults and their neurophysiological functions. Accordingly, the consistency in our 2 sets of correlational results offers evidence of an association between binge drinking and novel P3 amplitude, with additional evidence that the association is unlikely because of unmeasured third variable family confounds.
