Abstract
McGurk effect is a multisensory illusion in which one perceives another consonant when the audio recording of a consonant is presented with visual image of a different consonant. For example, auditory "ga" stimulus combined with visual "ba" stimulus may result in perception of "da." Frequency of McGurk effect experience may be affected by many factors such as expectations, general sensory preference, and sensory system efficiency. There are also large differences among individuals in the rate of McGurk effect occurrence. The goal of this study was to investigate the influence of the context which manipulates participants' expectation on McGurk effect. We used 4 types of contexts: neutral (black screen), congruent (auditory and visual stimuli show the same syllabi), incongruent (auditory and visual stimuli show different syllabi), and mismatch (auditory syllabi are combined with video in which a speaker reads sentences). The duration of the context was 2 sec for neutral context, and 1, 2, 4, or 8 syllabi for the other contexts. After the context stimulus, a gray screen was presented for 1 sec before the target stimulus. The target stimulus was either normal audio-visual video (auditory and visual components show the same syllable twice) or McGurk stimulus (auditory and visual components are created in one of the combinations that are known to produce McGurk effect; the same combination of the syllable is repeated twice). The participant indicated the perceived syllable (consonant) by a button press. The order of the context type and the target stimulus type were randomized. Surprisingly, the results did not show a significant effect of the context type on McGurk percept. On the other hand, there was a significant effect of context duration such that the four-syllable context produced less frequent McGurk percept compared to shorter or longer contexts.
Meeting abstract presented at VSS 2017