How the speaker's emotional facial expressions may affect language comprehension

During communicative face-to-face interactions, emotional expressions are typically processed along with auditory speech. Although previous research has demonstrated the interaction between emotion and linguistic processes, so far no study has focused on the effect of the speaker's emotional facial expression on natural language processing. In the present event-related potential (ERP) study, participants listened to spoken sentences while seeing the portrait of the speaker's face with either happy, neutral, or fearful emotional expression. In Study 1A, the N400 effect, a neural marker of semantic comprehension, was unaffected by the speaker's emotional expression. In Study 1B, we manipulated morphosyntactic agreement. The P600 effect was boosted by the happy emotional expression. This may be interpreted as reflecting additional effort in linguistic reanalysis, in line with the heuristic processing style that characterises positive emotions. The present results demonstrate an influence of the speaker's emotional facial expressions on non-emotional language processing during audiovisual communicative interactions.