Abstract
Mothers are concerned about their firstborn children's acceptance of a baby sibling. Observing children's reactions to mothers interacting with an infant doll simulator has been offered as one means of seeing how children will react to the baby sibling. A longitudinal pilot study with 30 pregnant mothers and their firstborn children was conducted comparing children's behaviors to mother-doll interaction in the laboratory before birth with behaviors during home observations of mother-sibling interaction 1 month after birth. Children responded to mother-doll and mother-sibling interaction differently, with no significant associations across children's behaviors in mother-doll and mother-sibling interactions. The use of an infant doll simulator before birth did not reliably predict children's behavioral adjustment after the birth of a baby sibling.