Data of the experiment on the unisensory vs. multisensory nature of the McGurk Effect

The McGurk effect is traditionally viewed as a prime example of multisensory integration, where a novel percept (e.g., "da") emerges from the fusion of conflicting auditory (e.g., /ba/) and visual (e.g., /ga/) inputs. However, this effect can also be explained through unisensory mechanisms, specifically the visual dominance hypothesis, where visual input may dominate auditory processing by capturing attention. To explore this, an experiment was conducted with participants exposed to different combinations of auditory and visual consonant-vowel (CV) pairs, including voiced and voiceless phonemes, across five places of articulation. The results show that both auditory and visual dominance can occur in the McGurk effect, with visual dominance varying by place of articulation. Visemes from the front of the mouth (e.g., bilabial) were more consistently perceived within their category, while those from the back (e.g., glottal) led to more variable perceptions. Additionally, visual cues alone could induce the perception of a consonant-vowel (CV) pair, even without an auditory consonant present. These findings suggest that the McGurk effect may not result from audio-visual fusion but rather from unisensory dominance, either visual or auditory.