Electrodermal and respiratory synchrony in couple therapy in distinct therapeutic subsystems and reflection periods.

Synchrony in the multi-person context of systemic therapy is a complex and understudied phenomenon. We analyzed respiratory and electrodermal synchronies within a couple therapy system with two therapists to determine whether dyadic subsystems between each client and therapist synchronized differently. We also studied synchrony in reflection periods, in which the therapists discussed the therapy process with clients listening. Finally, we examined the association of synchronies with alliance and outcome. A sample of 22 therapy sessions in which electrodermal activity (EDA) and respiration were recorded were analyzed. Self-report measures of session alliance and outcome were obtained. Synchrony computation was based on windowed cross-correlation using surrogate synchrony and segment-wise shuffling of physiological time series. The results supported the presence of EDA synchrony for the client-therapist and therapist-therapist dyads but not client-client dyads across entire sessions. No significant synchronies were found for respiration behavior. A similar picture was found in reflection periods. Clients' well-being as well as therapists' alliance ratings were significant predictors of client-client EDA synchrony. Our results point to the relational meaning of synchrony and its importance for understanding couple psychotherapy, particularly the reflection periods. Challenges involved in extending synchrony computation to multi-person settings were highlighted.