Mother–Child Biobehavioral Synchrony and Its Association With Social Functioning in Autistic School‐Aged Children

Parent-child biobehavioral synchrony, or the concordance of behavior and physiological indicators between individuals, is theorized to support children's social development; however, this relationship has yet to be investigated in autistic children. This study examined whether moment-to-moment physiological synchrony-indexed via respiratory sinus arrhythmia (RSA)-and its interface with global levels of behavioral synchrony was associated with the pragmatic language skills and friendship quality of school-aged autistic children in 40 mother-child dyads. Mother-child dyads participated in a collaborative task, from which RSA synchrony and behavioral synchrony were assessed. Mothers and their autistic children demonstrated negative RSA synchrony, such that when one partner displayed an increase in RSA, the other partner showed a decrease in RSA. The extent of behavioral synchrony between mothers and their children did not moderate the strength of concordance between mother and child RSA. Negative RSA synchrony was associated with better pragmatic language skills in autistic children from mother-child dyads who displayed high levels of behavioral synchrony. These findings highlight the complexity of dyadic synchrony, suggesting that the coordination of mother-child RSA, in conjunction with behavioral synchrony, may aid in the development of social skills in autistic children that extend beyond the immediate caregiver context. However, larger longitudinal studies are needed to confirm this.