Situating language in a minimal social context: how seeing a picture of the speaker's face affects language comprehension.

Natural use of language involves at least two individuals. Some studies have focused on the interaction between senders in communicative situations and how the knowledge about the speaker can bias language comprehension. However, the mere effect of a face as a social context on language processing remains unknown. In the present study, we used event-related potentials to investigate the semantic and morphosyntactic processing of speech in the presence of a photographic portrait of the speaker. In Experiment 1, we show that the N400, a component related to semantic comprehension, increased its amplitude when processed within this minimal social context compared to a scrambled face control condition. Hence, the semantic neural processing of speech is sensitive to the concomitant perception of a picture of the speaker's face, even if irrelevant to the content of the sentences. Moreover, a late posterior negativity effect was found to the presentation of the speaker's face compared to control stimuli. In contrast, in Experiment 2, we found that morphosyntactic processing, as reflected in left anterior negativity and P600 effects, is not notably affected by the presence of the speaker's portrait. Overall, the present findings suggest that the mere presence of the speaker's image seems to trigger a minimal communicative context, increasing processing resources for language comprehension at the semantic level.