Emotional Content and Semantic Structure of Dialogues Predict Interpersonal Neural Synchrony in the Prefrontal Cortex

Abstract

AbstractA fundamental characteristic of social exchanges is the synchronization of individuals’ behaviors, physiological responses, and neural activity. However, the influence of how individuals communicate in terms of emotional content and expressed associative knowledge on interpersonal synchrony has been scarcely investigated so far. This study addresses this research gap by bridging recent advances in cognitive neuroscience data, affective computing, and cognitive data science frameworks. Using functional near-infrared spectroscopy (fNIRS) hyperscanning, prefrontal neural data were collected during social interactions involving 84 participants (i.e., 42 dyads) aged 18-35 years. Wavelet transform coherence was used to assess interpersonal neural synchrony between participants. We used manual transcription of dialogues and automated methods to codify transcriptions as emotional levels and syntactic/semantic networks. Our quantitative findings reveal higher than random expectations levels of interpersonal neural synchrony in the superior frontal gyrus (p= 0.020) and the bilateral middle frontal gyri (p<0.001;p= 0.002). Stepwise models based on dialogues’ emotional content only significantly predicted interpersonal neural synchrony across the prefrontal cortexConversely, models relying on semantic features were more effective at the local level, for predicting brain synchrony in the right middle frontal gyrusGenerally, models based on the emo-tional content of dialogues lose predictive power when limited to data from one region of interest at a time, whereas models based on syntactic/semantic features show the opposite trend, losing predictive power when incorporating data from all regions of interest. Moreover, we found an interplay between emotions and associative knowledge in predicting brain synchrony, especially in social interactions based on role-play techniques, providing quantitative support to the major role played by the prefrontal cortex in conditions of identity faking. Our study identifies a mind-brain duality in emotions and associative knowledge reflecting neural synchrony levels, opening new ways for investigating human interactions.