Overall, the findings support the conceptual distinction between EC and reactive undercontrol (impulsivity). For example, impulsivity but not EC tended to differentiate the internalizing group from the control group at T3, whereas EC was a more consistent predictor than impulsivity of change in externalizing problems. Thus, future work may benefit from careful differentiation between more voluntary EC and less voluntary and more reactive behaviors that reflect over- versus undercontrol. Such work is important because it is possible that EC is more malleable (because it is voluntary) than is reactive control and a better target for intervention.
