Presentation Information
[P3-40]Tracking vocal turn-taking and inter-brains synchrony in human interactions
*Mami Terao1, Kazuo Okanoya1,2 (1. Teikyo University, 2. The University of Tokyo)
Keywords:
communication,turn-taking,brain activity,synchrony
This study aims to quantitatively investigate the universal mechanisms underlying communicative behavior at both behavioral and neural levels. In everyday life, our actions are dynamically shaped by interactions such as conversations and gestures. Although individual behavioral patterns are autonomous, an increasing body of evidence suggests that the neural activity of interacting partners can become temporally synchronized during communication (e.g., Cui et al., 2012). Recent advances now allow for the non-invasive measurement of brain states during multi-person communication tasks (e.g., Ahn et al., 2017). However, the neural processes underlying behavioral coordination and inter-brain synchrony remain unclear. While numerous social factors—such as interpersonal relationships and facial expressions—contribute to communication, this study focuses on the phenomenon of inter-brain synchrony. Specifically, we examined the similarity of neural activity and its relationship to behavior in a simple turn-taking task in which participants alternately emit a short vocalization. We hypothesized that smoother communication would be associated with stronger inter-brain synchrony in regions involved in action prediction. In our pilot experiment, we recorded EEG data (32 channels per participant) during a turn-taking vocal exchange task and analyzed event-related potentials (ERPs). The results revealed simultaneous peaks in central regions during both speaking and listening phases, suggesting the presence of preparatory activity during speech production and anticipatory responses to partner speech. Future work will involve manipulating inter-brain synchrony using non-invasive brain stimulation techniques (e.g., transcranial alternating current stimulation, tACS) to causally examine its effect on behavioral coordination. We also plan to analyze the temporal dynamics of synchrony formation to identify the neural substrates engaged at each stage. These findings may advance our understanding of the neural basis of social interaction and inform clinical research on communication disorders (Work supported by JSPS 23H05428 to KO).