The typical and atypical development of dynamic self-regulation and coregulation of respiratory sinus arrhythmia in mothers and children across early childhood

We examined the development of mother-child dynamic self-regulation and coregulation of respiratory sinus arrhythmia (RSA) from ages 3 to 4, and variations by harsh parenting. RSA was collected from at-risk mother-preschooler dyads during a challenging task (N = 129; 53% female; 63.6% White; 24.8% Latinx; collected 2013-2017). Across development, lower-risk mothers showed increased RSA self-regulation inertia and decreased mother-led RSA coregulation with children, supporting the theory that parents externally regulate young children, which weakens as children develop regulatory skills. Conversely, harsher mothers showed increased mother-led RSA coregulation and their children showed increased RSA self-regulation inertia (implying less flexibility), suggesting children of harsher mothers experience increasing physiological regulatory difficulties and receive or need greater external regulation from mothers across early childhood.