Associations of Aggressive and Prosocial Behaviors With Friendship Quality Before and After the Transition to Secondary School

This study examined associations of aggressive and prosocial behaviors with perceived support and negativity in children’s best friendships before and after the transition to secondary school ( N = 1, 073; 49.2% girls). Teachers rated children’s aggressive and prosocial behaviors in grades 1, 3, 4, and 6 of primary school. In grade 6 and the first 2 years of secondary school, children rated perceived support and negativity with their best friend. Growth curve analyses showed that increasing aggression combined with infrequent prosocial behavior predicted lower perceived support at the end of primary school and beyond, albeit only for girls. In contrast, high aggression combined with frequent pro-social behavior was unrelated to perceived support and conflict for both sexes. These results suggest that prosocial behaviors may be beneficial to buffer the effects of aggression on perceived support and conflict with the best friend, particularly for girls.