Social class differences in dyadic involvement during infancy.

The social interactions of 60 mother-infant pairs were observed for 25 min in a seminaturalistic setting when the infants were 6 months old and again at 20 months. 46 of the infants were termed at high risk for later school failure due to the socioeconomic situations of their families. Half of these high-risk infants had been randomly assigned to an early intervention program. The remaining group of 14 infants was a sample drawn from the general population. Principal components analyses of the 10 behaviors scored during the session yielded a first component at both 6 and 20 months which represented "dyadic involvement." Comparing the 3 groups of dyads on the proportion within each who scored positively on the dyadic-involvement component, it was evident that the groups did not differ at 6 months but did differ at 20 months. The changes in level of interaction across time were compared with changes in scores on developmental tests. Results indicated that higher dyadic involvement at 20 months was associated with higher intellectual performance.