To evaluate whether there was a moderating relationship between SOB and dopamine gene polymorphisms on the behavioral traits in this study, DRD2 and DRD4 were added as independent variables in the factorial ANOVA and binary logistic regression models. We found a significant interaction effect of DRD2×DRD4 on total sensation seeking (SSS-Total; F [1,145] = 6.883, p = .010), which was not observed in previous models that did not include SOB. Among those without A1 alleles (A1−), long DRD4 alleles (L+) were associated with decreased SSS-Total, but the reverse was true among those with A1 alleles (A1+). In addition, there was an interaction effect of SOB×DRD4 on EIQ-V (F[1,156] = 9.878, p = .002) as illustrated in Figure 2. On all other scales, no new significant associations were evident.
