Coparenting and children’s temperament predict firstborns’ cooperation in the care of an infant sibling.

This study examined how coparenting and firstborn children's temperament predicted children's cooperative behavior in response to maternal requests for assistance in the care of a 1-month-old infant sibling. Children's cooperative responding was observed during a diaper change session for 216 firstborns (ages 13 to 70 months; M = 32). Parents also completed questionnaires assessing coparenting and children's temperament. Results suggested that...