Neural correlates of conversational feedback

This paper explores the brain correlates of conversational feedback (FB) in human-human and human-agent interactions, focussing on its impact on discourse and processing at semantic and pragmatic levels. The study investigates how FB, produced either congruously or incongruously, influences brain activity (EEG) during interactions between a doctor (the main speaker) and a patient (the listener). The results show that FB incongruity does not elicit an N400 response in either human-human or human-agent interactions. Instead, a P600 component emerges, especially in human-human interactions. This pattern aligns with the mechanism underlying the semantic P600 characterised by the absence of an N400 and the presence of a P600, here attributed to the dominant role of FB's pragmatic dimension. Additionally, the study identifies a P200 component in human-agent interactions, which is stronger for congruous FB, indicating high predictability in agent-produced feedback due to the unique and prototypical form of feedback generated for the agent. The findings highlight that FB's processing is more linked to activation at the pragmatic level than to semantic content. The study also suggests that variability in feedback, particularly in human-human interactions, should be addressed in future research on feedback.