Schizotypal Personality Traits and Multisensory Integration: An Investigation Using the McGurk Effect

Abstract

Multisensory integration, the process by which sensory information from different sensory modalities are bound together, is hypothesized to contribute to perceptual symptomatology in schizophrenia, in whom multisensory integration differences have been consistently found. Evidence is emerging that these differences extend across the schizophrenia spectrum, including individuals in the general population with higher levels of schizotypal traits. In the current study, we used the McGurk task as a measure of multisensory integration. We measured schizotypal traits using the Schizotypal Personality Questionnaire (SPQ), hypothesizing that higher levels of schizotypal traits, specifically Unusual Perceptual Experiences and Odd Speech subscales, would be associated with decreased multisensory integration of speech. Surprisingly, Unusual Perceptual Experiences were not associated with multisensory integration. However, Odd Speech was associated with multisensory integration, and this association extended more broadly across the Disorganized factor of the SPQ, including Odd or Eccentric Behaviour. Individuals with higher levels of Odd or Eccentric Behaviour scores also demonstrated poorer lip-reading abilities, which partially explained performance in the McGurk task. This suggests that aberrant perceptual processes affecting individuals across the schizophrenia spectrum may relate to disorganized symptomatology.

Schizotypal traits are not related to multisensory integration or audiovisual speech perception

“…Additionally, our findings that multisensory integration was not related to schizotypal traits in these individuals does not align with much of the related literature. Audiovisual multisensory integration has been previously investigated in relation to schizotypal traits in the general population, with increased integration being found in the form of stronger responses to the McGurk illusion (Muller, Dalal, & Stevenson, 2020) and the double-flash illusion (Ferri, Venskus, Fotia, Cooke, & Romei, 2018). Investigations using visual-tactile illusions, which require multisensory integration, have also been conducted.…”

Excitation/Inhibition imbalance increases the proneness to experience the sound-induced flash illusion by impairing multisensory causal inference in the schizophrenia spectrum

“…Patients with schizophrenia are more prone to experience the streaming-bouncing illusion [20], the McGurk effect [21] and the double flash illusion [22]. These impairments have also been observed in high schizotypal individuals for the McGurk [23] and the double flash illusion [24]. Despite the amount of empirical evidence available, there…”