Dyadic Neural Synchronization: Differences between Offline and Computer-assisted Online Verbal Interaction.

Computer-assisted online interaction (CAOI) has become predominant in daily life and is increasingly supplanting offline verbal interaction (FVI). Previous research has shown that face-to-face verbal interaction (VI) exhibits significant differences in interpersonal neural synchronization (INS) compared to computer-assisted online VI. However, the differences between various forms of FVI and CAOI remain unclear. In this work, we designed different forms of naturalistic VI tasks between dual persons and adopted electroencephalography (EEG) hyperscanning to simultaneously record neural activities from both participants. The experiment included three conditions: online versus offline, with versus without feedback, with versus without visual information or eye contact. Thirty-one pairs of labmates with ordinary levels of intimacy were recruited as subjects. To analyze the impacts of these VI forms on INS, we calculated intersubject correlation at both scalp and cortex levels and constructed brain-to-brain networks based on intersubject functional connectivity using the phase lag index at the scalp level and the phase locking value at the cortex level. We found that interactions with feedback exhibit higher synchronization than interactions without feedback. VIs with visual information or eye contact are more effective in eliciting stronger INS. Additionally, compared to FVI, CAOI exhibits weakened neural synchronization. Intriguingly, online text-based interaction also results in high neural coupling. Our study reveals significant differences in various CAOIs and FVIs concerning typical factors, providing crucial insights into the mechanisms of INS during online interactions.