Skilled musicians are indeed subject to the McGurk effect

Abstract

The McGurk effect is an illusion whereby speech sounds are often mis-categorized when the auditory cues in the stimulus conflict with the visual cues from the speaker's face. A recent study claims that 'skilled musicians are not subject to' this effect. It is not clear, however, if this is intended to mean that skilled musicians do not experience the McGurk effect at all, or if they just experience it to a lesser magnitude than non-musicians. The study also does not statistically demonstrate either of these conclusions, as it does report a numerical (albeit non-significant) McGurk effect for musicians and does not report a significant difference between musicians' and non-musicians' McGurk effect sizes. This article reports a pre-registered, higher-power replication of that study (using twice the sample size and changing from a between-to a within-participants manipulation). Contrary to the original study's conclusion, we find that musicians do show a large and statistically significant McGurk effect and that their effect is no smaller than that of non-musicians.