Mother-infant affect synchrony as an antecedent of the emergence of self-control.

This study examined relations between mother-infant affect synchrony and the emergence of children's self-control. Mother-infant face-to-face play and infant difficult temperament were examined at 3 and 9 months. Maternal and infant affective states at play were coded in 0.25-s frames, and synchrony was computed with cross-correlation functions. Self-control, verbal IQ, and maternal warm discipline were assessed at 2 years. Maternal synchrony with infant affect at 3 months (infant-leads-mother-follows relation) and mutual synchrony at 9 months (cross-dependence between maternal and infant affect) were each related to self-control at 2 years when temperament, IQ, and maternal style were partialed. Infant temperament moderated the relations of synchrony and self-control, and closer associations were found between mutual synchrony and self-control for difficult infants. Shorter lags to maternal synchrony at 3 months were independently related to self-control. The mutual regulation of affect in infancy, as moderated by temperament, is proposed as an important contributor to the emergence of self-regulation.