Nonverbal Synchrony and the Alliance in Psychotherapy for Major Depression: Disentangling State-Like and Trait-Like Effects

Given the importance of the alliance in psychotherapy, nonverbal synchrony has been suggested as a promising automatic objective marker of its levels and development. Accumulating research presents mixed results regarding the association between alliance and nonverbal synchrony. In the current study, we propose that one of the reasons for the inconsistencies is that previous studies did not disentangle trait-like characteristics from state-like changes occurring throughout treatment. To test this, we had 86 patients enrolled in an ongoing randomized controlled trial, along with their therapists, report their alliance levels after every session. Nonverbal movement synchrony was quantified by motion energy analysis for each of the 16 sessions of treatment. Findings suggest a significant association between nonverbal synchrony and the state-like effect of patient-reported alliance (p < .0001) but not for the trait-like effect. The results confirm the importance of disentangling the state-like and trait-like components because they may have distinct effects.