The association between P3 amplitude and externalizing behavior was not significant among AA participants when accounting for age and sex effects. While the magnitude of association between P3 amplitude and externalizing behavior was similar at the bivariate level among both EA and AA young adults (rEA = −0.09, rAA = −0.08), in the regression models when age and sex covariates are included, the association was no longer significant for AA participants. This may be due to smaller N’s for the AA adolescent and young adult groups, making it more difficult to detect small effects. Further research is needed with larger, diverse samples to address this limitation. The association between P3 amplitude and externalizing behavior was also not significant among EA adolescent participants when accounting for age and sex effects. However, the magnitude of the association between P3 amplitude and externalizing behavior among EA adolescents (β = −0.06) was similar to the significant association seen in the EA young adult group (β = −0.05). Therefore, the lack of significance among EA adolescents may be due to limitations of sample size (the largest N was available for EA young adults).
