The Influence of Speaker's Gaze on Sentence Comprehension: An ERP Investigation

Behavioral studies demonstrate the influence of speaker gaze in visually-situated spoken language comprehension. We present an ERP experiment examining the influence of speaker’s gaze congruency on listeners’ comprehension of referential expressions related to a shared visual scene. We demonstrate that listeners exploit speakers’ gaze toward objects in order to form sentence continuation expectations: Compared to a congruent gaze condition, we observe an increased N400 when (a) the lack of gaze (neutral) does not allow for upcoming noun prediction, and (b) when the noun violates gaze-driven expectations (incongruent). The later also results in a late (sustained) positivity, reflecting the need to update the assumed situation model. We take the combination of the N400 and late positivity as evidence that speaker gaze influences both lexical retrieval and integration processes, respectively (Brouwer et al., in press). Moreover, speaker gaze is interpreted as reflecting referential intentions (Staudte & Crocker, 2011).