Correlates and antecedents of nine-month infant behavior and mother-infant interaction

This study investigated the stability of infant irritability, motor activity, and sociability from the newborn period through the first nine months of life, and the relationship between mother and infant behavior over the same time period. Sixteen infants were assessed neonatally and the mother-infant pairs were observed in their homes at one, three, and nine months. The results identify mother and infant antecedents of nine-month infant behavior. Motor activity is most clearly related to newborn characteristics and least influenced by mother behavior. Fussing and crying is highly consistent from one and three to nine months, although mother behavior may contribute to this consistency. Sociability is related positively to maternal contact and responsiveness. Mother behavior at nine months is associated with both early infant and mother characteristics.