An EEG hyperscanning study during persuasion toward groupness. The frontal brain area activation as a function of role.

This hyperscanning study explored the electrophysiological (EEG) patterns of dyads during a naturalistic persuasive interaction, in which the persuader had to convince the receiver that choosing a group solution was the most effective way to solve a group hypothetical everyday situation. Fifteen dyads composed of a persuader and a receiver were involved in a persuasive interaction while EEG data were recorded. EEG frequency bands (delta, theta, alpha, beta and gamma bands) were analyzed, first, considering the distinct role of the participants and, second, dividing the dyads according to the perceived effectiveness of persuasion. The intra-brain results showed greater activation of the delta, theta and alpha bands in the frontal area of the persuader compared to the receiver. The inter-brain analyses reported a significantly increased dissimilarity activation for delta and theta band in the frontal area compared to more temporo-central and parieto-occipital regions, regardless of the perceived effectiveness of persuasion. To summarize, the process of enhancing groupness during a persuasive interaction generates in the persuader a specific EEG pattern involving mainly low frequency bands activation in the frontal brain regions, suggesting a significant attentional effort and emotional involvement.