Statistical Analyses
As explained above, we controlled for age in the analyses. To test the prediction that the HD group would demonstrate greater ERN during simulated discarding decisions relative to emotionally neutral decisions as compared to the control groups, we used a 3 (group) x 2 (task: ERN during the discarding task vs. neutral task) mixed analysis of covariance (ANCOVA), controlling for age. To test the prediction that the HD group would demonstrate greater right vs. left alpha asymmetry, we used 1-way ANCOVA, controlling for age. For our prediction that the HD group would demonstrate greater psychophysiological activity during the simulated discarding task relative to the neutral task compared to the control groups, we used 3 (group) x 2 (task: ETCO2, SCL, HRV, and HR during the discarding task vs. neutral task) mixed ANCOVAs, controlling for age. Finally, we used hierarchical multiple regression to test the prediction that the ERN during discarding decisions would predict SI-R scores, controlling for age.