Objective: The spill-over hypothesis suggests that childhood aggression results from spillover of interparental conflict to poor parenting, which promotes aggressive child behavior. This study was designed to examine the spill-over hypothesis in non-genetically related parent-child dyads from the toddler period through age 6.
Method: A sample of 361 sets of children, adoptive parents, and birth parents from the Early Growth & Development Study (EGDS) was assessed from child age 9 months to 6 years on measures of adoptive parent financial strain, antisocial traits, marital hostility, hostile parenting, and child aggression. Structural equation modeling was used to examine links from financial strain, parent antisocial traits, and marital hostility in infancy and toddlerhood to hostile parenting and child aggression at age 4.5 and 6 years.
Results: Spill-over of marital conflict from child age 18 to 27 months was associated with more parental hostility in mothers and fathers at 27 months. In turn, adoptive fathers’ parental hostility, but not mothers’, was associated with aggression in children at age 4.5 years. However, there was no significant spillover from hostile parenting at 4.5 years to child aggression at 6 years. Birth mother antisocial traits were unassociated with child
aggression.
Conclusions: This study is the first to examine spill-over of marital hostility to parenting to child aggression from toddlerhood through age 6 years in an adoption design, highlighting the impact of these environmental factors from the toddler to preschool period. The findings support the potential benefit of early identification of marital hostility.