LAUSR

Parent conflict is related to attenuated infant vagal reactivity, suggesting less effective regulation. Because infants' self-regulation develops in the context of coregulation, the current study examined a novel measure, flexibility, purported to reflect dyadic reorganization in response to contextual demands. Flexibility was expected to mediate the relation between greater conflict and lesser vagal reactivity during the reunion episode of the Face-to-Face Still-Face (FFSF). Six-month-old infants' and their mothers' (N = 53) affective behaviors were observed during the FFSF and heart rate data were collected for infants. Flexibility was computed using state-space analysis of dyadic behaviors and measured variability in and movement among dyadic states. Conflict was related to lesser infant vagal reactivity in the reunion through lower flexibility, suggesting less effective recovery from social stress. Flexibility may capture aspects of coregulation affected by environmental stress and may be one mechanism by which conflict contributes to developing vagal regulation.