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 exami ne 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 cohor ts of boys who had been rated as having disruptive behavior problems i n kindergarten and one normative cohort) while controlling for body si ze, pubertal status, and level of family adversity. Results: Heart rat e showed moderate stability at 1- and 2-year intervals in two of the t hree cohorts. The composite fighting score was related to heart rate f or 11-year-old boys in the normative cohort and 12-year-old boys in on e of the disruptive cohorts. Conclusion: These data support the conclu sion that there is a relationship between heart rate and aggression ev en within a low socioeconomic status sample.