EEG hyperscanning and behavioral synchronization during a joint action

Brain-to-brain coupling during cooperation is a core question of study on social interactions. The aim of the present study was to investigate the neural basis of interbrain cooperation and the cognitive performance underlying the execution of jointactions by using EEG coherence measures. Synchronicity of the cognitive variables (response times, RTs, and error rates, ERs) in response to an attentional task, intersubjective coherence analysis on EEG frequency bands, and correlational measures between cognitive and brain activity were considered during some steps of progressive reinforcing conditions. Fifteen couples of subjects performed an attentional task in eight temporal steps, stressing their good performance at the end of each step. The induced feedback affected both the cognitive performance and brain-to-brain coupling by increasing behavioral and brain synchronization when a positive feedback was furnished to the participants for their performance. Secondly, about the cortical contribution, high coherence effect was mainly observed when a positive reinforce was produced, but only for some low frequency bands within the prefrontal left area, compared to the right one. Thus, also a left lateralization effect was reportable. Finally, the cognitive and EEG coherence measures were shown to be correlated, with a significant similar trend anchored to the progressive feedback.