Interaction and development in the first year. I. The effects of prematurity.

Six month infant-mother interaction patterns were observed and 10 month Bayley MDI scores were obtained in 10 fullterm and 14 healthy preterm (less than 37 weeks) infants. Relationships among interaction parameters and intellectual performance are compared with those among earlier interaction patterns and development. At 6 months preterm dyads were more synchronised and had higher levels of interaction than fullterm dyads; preterm mothers demonstrated lower levels of affection. Fullterm variables reflecting unfocussed infant vocalising at 2, 3 and 6 months were negatively related to later development while those maternal variables indicating general and specific stimulation were positively related. Preterm infant vocalising levels at 3 and 6 months were positively related while 3 and particularly 6 month variables indicating maternal stimulation and high levels of dyadic interaction were negatively related to later development. In both groups early maternal state differentiation in responses was positively related to 10 month intellectual performance. Ten month MDI scores for the preterm group were lower than for the fullterm group. The results are discussed with respect to information processing abilities, optimal patterns of interaction for each kind of infant, and their differential paths of development in the first year.