Abstract:
The McGurk effect---the integration of visual information into speech perception---is well documented for English consonants. However, a recent attempt to extend the effect to musical events (violin plucks and bows) showed only a weak visual influence on perception [Saldana and Rosenblum, Percept. Psychophys. 54, 406--416 (1993)]. Thus the conditions required to produce a strong McGurk effect are unknown. The effect may be specific to perception of native phonological categories; alternatively, it may apply to dynamic vocal-tract events in general. This study tested for a McGurk effect with click consonants, which are phonological in some African languages, but are treated as nonspeech by English speakers [Best, McRoberts, and Sithole, JEP:HPP 14, 345--360 (1988)]. Audio bilabial, dental, and lateral clicks, spoken in isolation and coarticulated with a vowel, were dubbed onto video presentations of each click. Parallel stimuli were made from English stops in syllables and with their excised bursts only. English-speaking subjects made bimodal matching judgments on the dubbed stimuli. Results revealed a visual influence on perception of the non-native sounds that was somewhat weaker than for native speech, although stronger than Saldana and Rosenblum's effect for violin sounds. [Work supported by NIH.]