Cardinal and Steinberg provide evidence from both laboratory animal and human studies indicating that behavior is controlled by two distinct brain systems, one activational and the other inhibitory. This conceptual framework continues to be a useful integrative framework in developmental neurobiology and psychology. Despite the conceptual framework that posits a two-system control of high-risk behavior, it is notable that the bulk of research related to this topic has focused on one system in isolation from the other. Since the activational and inhibitory systems are constructs that are amenable to investigation using both laboratory animals and human subjects, it seems that a fruitful avenue for future interdisciplinary research would be to ascertain the interactive effect of these systems across the periadolescent period.