SYNCON · The role of interpersonal neural SYNchrony during verbal CONversations: Correlation, Causation and Personalization

Verbal conversations are a hallmark of human social interaction and are supported by various socio-cognitive processes promoting specific conversation patterns. For instance, more engaging conversations are marked by how often and quickly participants switch turns speaking (turn-taking). Similarly, an engaging conversation is also marked by the interlocutors converging towards a common phonetic space (phonetic convergence). One of the neural mechanisms supporting these conversation patterns is proposed to be interpersonal neural synchrony (INS), the coupling of brain oscillations between two interlocutors. However, only a few studies truly tested the role of INS during free-flowing conversations. These studies have some limitations as they were either conducted in a non-ecologically valid context or the evidence was purely correlational. In addition, important inter-dyadic differences were neglected. The present project – SYNCON – aims to overcome these limitations by combining EEG hyperscanning with multi-person brain stimulation (tACS) and personalized neuroscience. I will first measure the correlation between INS and mutually engaged conversations marked by enhanced turn-taking and phonetic convergence. The measurement will yield a dyad-specific INS profile, considering properties such as frequency, phase, and topography. Utilizing a longitudinal design, these profiles will allow me – in a second experiment – to exogenously induce INS between interlocutors and, in turn, promote mutually engaged conversations (i.e., increased turn-taking and phonetic convergence). Understanding the causal role of INS in conversations will have groundbreaking applications for facilitating interpersonal communication across therapeutical and educational contexts. Accordingly, this project will address critical gaps in our understanding of the neural underpinnings of human communication and its potential use in applied contexts.