Say Less! Backchanneling and HPA-axis Attunement, But Not Semantic Synchrony, Relate to Couples’ Relationship Quality Across the Transition to Parenthood

Objective: Language and physiology each carry information about how couples attune, yet are rarely studied together, especially during vulnerable periods such as the transition to parenthood. Semantic synchrony , or shared meaning across partners’ speaking turns, is a potential marker of relational functioning that may reflect couples’ use of active listening and reflection to validate one another’s concerns. Semantic synchrony may also intersect with other dimensions of health-relevant synchrony such as covariation in partners’ hypothalamic-pituitary-adrenal (HPA) axis. Methods: The present study examined semantic and HPA-axis/cortisol synchrony in 100 expectant parent dyads during lab-based discussions in pregnancy and at six months postpartum. Results: Semantic synchrony was present across all conversations and was strongest during discussions of conflict. Positive HPA-axis synchrony emerged at both timepoints, but semantic and HPA-axis synchrony were unrelated. Semantic synchrony during discussions about relationship conflict was negatively associated with partners’ validation of one another (i.e., communicating sincere understanding), but this association was primarily attributable to couples’ backchanneling (e.g., “ mmhm ,” “ uh-huh ”) – brief verbal expressions that communicate understanding without interrupting the speaker. Neither form of synchrony predicted relationship quality at either visit, with one exception: postpartum HPA-axis synchrony marginally predicted couples’ relationship quality ( P =.04). Moreover, partners’ backchanneling during discussions of conflict was positively associated with participants’ relationship quality. Conclusions: Together, these findings suggest that it is backchanneling, not semantic synchrony, that is associated with greater validation and relationship quality and may therefore serve as a potential linguistic marker of relational functioning.