Sibling Proactive and Reactive Aggression in Adolescence

We describe sibling proactive and reactive aggression in middle and late adolescence. Participants were 8th (n = 303, Mage = 13.74 years, SD = .59) and 12th (n = 300, Mage = 17.73 years, SD = .56) grade adolescents who completed an in-school survey. Findings revealed that these adolescents were significantly more likely to engage in reactive than proactive aggression with their closest-aged sibling. However, 8th grade adolescents reported greater aggression toward their closest-aged sibling than did 12th grade adolescents. In addition, sex composition of the sibling dyad moderated the association between sibling relationship quality (i.e., warmth and rivalry) and both proactive and reactive aggression indicating unique links for brother-brother and older sister-younger brother pairs.