Mothers' attuned responses to infant affect expressivity promote earlier achievement of language milestones

To investigate infants' affective expressivity and maternal attuned responsiveness to infant expressivity in relation to early language achievement, 77 dyads were visited in their homes at 9 and 13 months, and mothers were interviewed about their children's language between 9 and 21 months. Maternal responses that were attuned to infant affect, by selectively matching either the gradient features or the valence of infants' affective expressions, were more predictive of children's language achievement than maternal nonmatching responses; and maternal matching responses at 9 months were more predictive of children's language achievements than maternal responses at 13 months. Moreover, maternal matching responses at 9 months predicted second-year language achievements over and above infant affect expressivity at 9 and 13 months, and over and above maternal matching responses at 13 months. Infants' affective expressivity per se was not predictive.