This study was designed to determine the contributions of mothers and fathers to infant social development. Nine 1 0-month-olds , 12 fourteen-month- olds, and 12 eighteen-month-olds were observed with their mothers and fathers in a laboratory situation. Parent-infant interactions were videotaped during three different episodes: Mother-infant dyad, father-infant dyad, and mother- father-infant triad. Findings revealed different interaction patterns as a result of the ages of infants and the interaction situation. Older infants and their parents engaged in more verbal behavior (responsive talk, social speech, and story reading) than younger infants and their parents. It was found that parents and infants interacted with each other more when observed in dyads than in triads. However , it is argued that situation may not be a significant factor, if the duration of interactions, is controlled for. There were no significant differences between mothers and fathers in the amount of interaction they engaged in with their infants . Likewise, there were few gender differences across age groups in parent-infant interaction. The data are discussed with respect to the importance of early interaction patterns and the need to control for interaction time when examining second-order effects
