Trait mindfulness predicts inter-brain coupling during naturalistic face-to-face interactions

In recent years, the benefits of practicing mindfulness have raised much public and academic interest. Mindfulness emphasizes cultivating awareness of our immediate experience, and has been associated with compassion, empathy and various other prosocial traits. However, experimental evidence pertaining to its prosocial benefits in social settings is lacking. In this study, we investigate neural correlates of trait mindfulness during naturalistic dyadic interactions, using both individual brain and inter-brain coupling measures. We used the Muse headset, a portable electroencephalogram (EEG) device, to record participants' brain activity during a ~10 minutes' naturalistic dyadic interaction (N = 62) in an interactive art setting. They further completed the Mindful Attention Awareness Scale (MAAS) and the Interpersonal Reactivity Index (IRI). This allowed us to ask whether inter-brain coupling during naturalistic interactions can be predicted by dyads' affective traits and trait mindfulness, respectively. First, we failed replicating prior laboratory-based findings with respect to individual brain responses as they relate to mindfulness. Trait mindfulness did, however, predict inter-brain coupling within dyads, in theta (~5-8 Hz, p < 0.001) and beta frequencies (~26-27Hz, p < 0.001). Finally, we found a negative correlation between personal distress and trait mindfulness (t(475) = -5.493, p < 0.001). These findings underscore the importance of conducting social neuroscience research in ecological settings and enrich our understanding of multi-brain neural correlates of mindfulness during social interaction, while raising critical practical considerations regarding the viability of commercially available EEG systems.