Ideal Versus Real Group Mental Representations During Communicative Exchange: A Hyperscanning Study

Group decision-making is a cognitive and emotional process influenced by mental representations of the group in terms of ideal and real dimensions. This study explored how communication about these representations affects decision-making as well as neural and autonomic responses. Using an electroencephalography (EEG), functional near-infrared spectroscopy (fNIRS), and biofeedback (BIO) hyperscanning paradigm, 28 participants divided into dyads discussed group decisions while self-representing either an ideal (Phase 1) or a real (Phase 2) group. EEG bands (delta, theta, alpha, beta, and gamma bands), oxygenated (O₂Hb) and deoxygenated hemoglobin (HHb), and autonomic measures (i.e., heart rate variability [HRV]) were recorded for individual and dyadic analyses. Single-subject analyses showed increased frontal low-frequency EEG bands, suggesting emotional involvement in all communication exchanges. Higher beta/gamma bands and HHb levels while subjects self-represented the real group indicated greater cognitive and perspective-taking effort. Increased HRV when discussing a group decision while mentally self-representing the ideal compared to the real group suggested greater emotion regulation. Euclidean distance analyses revealed increased delta dissimilarity within dyads, indicating higher emotional and cognitive engagement regardless of group representation. Beta dissimilarity increased when discussing a group decision while mentally self-representing the real group, reflecting higher attentional and cognitive control demands. The multimodal hyperscanning paradigm (combining EEG/fNIRS/BIO) offers complementary insights into the study of communicative exchanges. These findings enhance the understanding of decision-making dynamics and support strategies to improve group communication.