Additive and Interactive Relations of Personality and Cognition with Externalizing Behaviors

Personality and cognition offer robust frameworks to understand the individual differences associated with externalizing behaviors. However, these literatures have historically been separated in the study of the externalizing spectrum. The present study used comprehensive tests of additive and interactive effects to examine the utility of integrating models of personality and cognition to understand externalizing behaviors in young adulthood (N = 1,179; Human Connectome Project) and late childhood (N = 11,448; Adolescent Brain Cognitive Development Study). Generally, the average effects of personality traits in young adulthood and the additive effects of impulsigenic traits and cognition in late childhood demonstrate the utility of integrating personality and cognition to understand incidence of early onset EXT. Although interaction effects were detected, they were small and practically negligible in their explanation of variance in externalizing behaviors. Results support primarily focusing on additively integrating these literatures to understand the individual differences related to externalizing behaviors.