Brain-to-Brain Synchrony Tracks Real-World Dynamic Group Interactions in the Classroom
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Viinikainen M. Jääskeläinen I.P. Hari R. Sams M. Emotions promote social interaction by synchronizing brain activity across individuals.Proc. Natl. Acad. Sci. USA. 2012; 109: 9599-9604Crossref PubMed Scopus (287) Google Scholar], and contextual factors [15Dikker S. Silbert L.J. Hasson U. Zevin J.D. On the same wavelength: predictable language enhances speaker-listener brain-to-brain synchrony in posterior superior temporal gyrus.J. Neurosci. 2014; 34: 6267-6272Crossref PubMed Scopus (71) Google Scholar] may underpin similarities and differences in neural activity across people. However, most studies to date suffer from various limitations: they often lack direct face-to-face interaction between participants, are typically limited to dyads, do not investigate social dynamics across time, and, crucially, they rarely study social behavior under naturalistic circumstances. Here we extend such experimentation drastically, beyond dyads and beyond laboratory walls, to identify neural markers of group engagement during dynamic real-world group interactions. We used portable electroencephalogram (EEG) to simultaneously record brain activity from a class of 12 high school students over the course of a semester (11 classes) during regular classroom activities (Figures 1A–1C; Supplemental Experimental Procedures, section S1). A novel analysis technique to assess group-based neural coherence demonstrates that the extent to which brain activity is synchronized across students predicts both student class engagement and social dynamics. This suggests that brain-to-brain synchrony is a possible neural marker for dynamic social interactions, likely driven by shared attention mechanisms. This study validates a promising new method to investigate the neuroscience of group interactions in ecologically natural settings.