Longitudinal associations between parents' hostility and siblings' externalizing behavior in the context of marital discord.

This study examined longitudinal associations between parents' hostility and siblings' externalizing behavior in the context of interparental discord. The sample included 116 families (mothers, fathers, 2 siblings) assessed in middle childhood, when siblings were, on average, 8 and 10 years old, and in adolescence, at average ages of 14 and 16 years. Parents reported on their hostility toward each child and on each child's externalizing problems. Raters observed interparental hostility, and parents rated their marital quality. Results indicated both within-family and between-families effects. Specifically, the child who received more parental hostility than his or her sibling showed greater increases in externalizing problems than his or her sibling; this association was moderated by marital discord. In addition, the child who exhibited more behavioral problems than his or her sibling received greater increases in hostile mothering than did his or her sibling. Between-families effects were evident, in that children's externalizing problems were associated with increases in mothers' hostility toward both children in the family. Results support transactional models of development and family systems theory.