Seeing a talking face matters to infants, children and adults : behavioural and neurophysiological studies

Abstract

Everyday conversations typically occur face-to-face. Over and above auditory information, visual information from a speaker's face, e.g., lips, eyebrows, contributes to speech perception and comprehension. The facilitation that visual speech cues bring"" termed the visual speech benefit""are experienced by infants, children and adults. Even so, studies on speech perception have largely focused on auditory-only speech leaving a relative paucity of research on the visual speech benefit. Central to this thesis are the behavioural and neurophysiological manifestations of the visual speech benefit. As the visual speech benefit assumes that a listener is attending to a speaker's talking face, the investigations are conducted in relation to the possible modulating effects that gaze behaviour brings. Three investigations were conducted. Collectively, these studies demonstrate that visual speech information facilitates speech perception, and this has implications for individuals who do not have clear access to the auditory speech signal. The results, for instance the enhancement of 5-month-olds' cortical tracking by visual speech cues, and the effect of idiosyncratic differences in gaze behaviour on speech processing, expand knowledge of auditory-visual speech processing, and provide firm bases for new directions in this burgeoning and important area of research.

Date of Award	2020
Original language	English