The lateralization of lip-reading: a second look.

Photographs of unfamiliar speaking faces were matched by normal right-handed subjects on the basis of perceived mouth-shape (i.e. visible speech sound) across different face-views. A clear left-hemisphere (RVF) processing advantage emerged, which was absent when the task was that of identity matching. In contrast to earlier proposals, the extraction of lip-shape from face photographs may be better managed by left-hemisphere- than right-hemisphere mechanisms even at its initial stages. This may contribute to the observed patterns of dissociations in speech-reading and in audiovisual speech-processing in neurological patients.