Kindhearted: Ethical guilt and ethical heart rate reactivity codevelop with aggression across childhood

Largely cross-sectional evidence indicates that ethical guilt is a robust predictor of childhood aggression. However, the underlying mechanisms of ethical guilt-in part assessed as ethical heart rate (HR) reactivity in the present study-are less clear, and longitudinal associations between ethical guilt, its underlying mechanisms, and aggression have not been explored. The present study used a multicohort longitudinal design to assess these constructs across early and middle childhood. At the beginning of the study and 2 years later, cohorts of 4- and 8-year-olds (ns = 150; N = 300) reported their guilt in response to an ethical transgression (i.e., pushing) and a nonethical transgression (i.e., breaking a classroom rule), and their HR was measured while they imagined committing these acts. Caregivers reported their child's aggression at each time point via questionnaire. Latent difference score models indicated that, regardless of cohort, children who increased in their ability to prioritize ethical guilt over 2 years were more likely to decrease in aggression over the same period. Moreover, children whose HR reactivity became more sensitive to ethical transgressions over time showed corresponding declines in aggression over time. Overall, these findings highlight the potential protective roles of children's capacities to react affectively and autonomically to the gravity of ethical transgressions across early and middle childhood.