Semantic priming from McGurk words: Priming depends on perception

The McGurk effect is an illusion in which visible articulations alter the perception of auditory speech (e.g., video 'da' dubbed with audio 'ba' may be heard as 'da'). To test the timing of the multisensory processes that underlie the McGurk effect, Ostrand et al. Cognition 151, 96-107, 2016 used incongruent stimuli, such as auditory 'bait' + visual 'date' as primes in a lexical decision task. These authors reported that the auditory word, but not the perceived (visual) word, induced semantic priming, suggesting that the auditory signal alone can provide the input for lexical access, before multisensory integration is complete. Here, we conceptually replicate the design of Ostrand et al. (2016), using different stimuli chosen to optimize the success of the McGurk illusion. In contrast to the results of Ostrand et al. (2016), we find that the perceived (i.e., visual) word of the incongruent stimulus usually induced semantic priming. We further find that the strength of this priming corresponded to the magnitude of the McGurk effect for each word combination. These findings suggest, in contrast to the findings of Ostrand et al. (2016), that lexical access makes use of integrated multisensory information which is perceived by the listener. These findings further suggest that which unimodal signal of a multisensory stimulus is used in lexical access is dependent on the perception of that stimulus.