LONGITUDINAL PATTERNS OF HEART-RATE AND FIGHTING BEHAVIOR IN 9-YEAR-OLD 12-YEAR-OLD BOYS

Objective: To assess the temporal stability of heart rate and to examine its relationship with fighting behavior. Method: Heart rate at ages 9 through 12 was compared to a composite measure of fighting behavior in three cohorts of low socioeconomic status boys (n = 138; two cohorts of boys who had been rated as having disruptive behavior problems in kindergarten and one normative cohort) while controlling for body size, pubertal status, and level of family adversity. Results: Heart rate showed moderate stability at 1- and 2-year intervals in two of the three cohorts. The composite fighting score was related to heart rate for 11-year-old boys in the normative cohort and 12-year-old boys in one of the disruptive cohorts. Conclusion: These data support the conclusion that there is a relationship between heart rate and aggression even within a low socioeconomic status sample.