Naturalistic Movie Viewing Reveals a Distributed Network Supporting Audiovisual Speech Processing

Audiovisual speech during naturalistic movie viewing recruits consistent left pSTS and STG activation across two full-length films, with audiovisual speech engaging a broad left-lateralized network.

• Why it matters: Traditional audiovisual speech studies use simplified stimuli that limit ecological validity, leaving uncertainty about how multisensory speech processing operates during real-world experience.
• What they did: fMRI data from 38 participants watching 500 Days of Summer and Citizenfour were analyzed using manual word onset timing and modality labels (audiovisual vs. auditory-only).
• The result: Compared with auditory-only speech, audiovisual speech recruited angular gyrus, posterior temporal cortex, temporal pole, inferior frontal gyrus, and right cerebellum, with effects also present in single-subject data.