Non-Modality specific speech coding: The processing of lip-read information

Abstract

Two experiments investigated the nature of the code in which lip‐read speech is processed. In Experiment 1 subjects repeated words, presented with lip‐read and masked auditory components out of synchrony by 600 ms. In one condition the lip‐read input preceded the auditory input, and in the second condition the auditory input preceded the lip‐read input. Direction of the modality lead did not affect the accuracy of report. Unlike auditory/graphic letter matching (Wood, 1974), the processing code used to match lip‐read and auditory stimuli is insensitive to the temporal ordering of the input modalities. In Experiment 2, subjects were presented with two types of lists of colour names: in one list some words were heard, and some read; the other list consisted of heard and lip‐read words. When asked to recall words from only one type of input presentation, subjects confused lip‐read and heard words more frequently than they confused heard and read words. The results indicate that lip‐read and heard speech share a common, non‐modality specific, processing stage that excludes graphically presented phonological information.