Perception of movement mimicry and working alliance in a psychotherapy session: the role of observer characteristics and task instruction

Background: In psychotherapy, the mirroring of nonverbal behaviour (mimicry) has been linked to more favourable patient evaluations of the therapeutic relationship. Because video recordings are commonly used in clinical supervision, it is important to understand how nonverbal mimicry is perceived by third-party observers. Across two experiments, we investigated the accuracy of mimicry perception and examined associations with observer characteristics (emotional competence and mindfulness) as well as task instructions. Method: In Experiment 1, 132 participants (70% female; mean age = 30.12 years, SD = 11.92; 80% psychology students) were randomly assigned to view a video of a patient–therapist interaction that either included 10 instances of movement mimicry or a digitally edited version in which these instances were removed. Participants were instructed to watch the video attentively but were not informed about the presence of mimicry. In Experiment 2, 94 participants (56% female; mean age = 24.97 years, SD =7.64; 80% psychology students) viewed the mimicry video with explicit instructions to attend to nonverbal behaviour. Results: Experiment 1 indicated that the presence of mimicry did not affect observers’ ratings of the working alliance. The number of perceived instances of mimicry varied substantially across participants and was positively associated with self-reported emotion regulation abilities. Observers underestimated the number of mimicry instances in the mimicry video. In Experiment 2, participants slightly overestimated mimicry. In this experiment, perceived mimicry frequency was positively correlated with working alliance ratings. Conclusion: These findings highlight the importance of both observer characteristics and task instructions in the assessment of nonverbal mimicry in psychotherapy contexts. However, the observed effects were small and based on a specific instance of mimicry within a single dyad evaluated by psychology students. Future research should seek to replicate these findings using a broader range of interaction dyads (e.g., patients with different mental disorders), as well as evaluators with varying levels of expertise and professional backgrounds (e.g., psychotherapists).