Individual differences in ageing, cognitive status, and sex on susceptibility to the sound-induced flash illusion: A large-scale study

Although there is some evidence suggesting that audiovisual integration is inefficient in older adults, and that such inefficiency is associated with age-related functions such as mild cognitive impairment, falls, and balance maintenance, these associations have yet to be demonstrated in a population-representative study of ageing. Based on a sample of 3,955 adults aged over 50 years, we investigated the role of age, cognitive status, and sex on susceptibility to the sound-induced flash illusion (SIFI) as a measure of audiovisual temporal integration, while controlling for a range of covariates. We developed a hierarchical Bayesian, ordinal-regression model to determine which variables predicted audiovisual integration. Higher susceptibility to the SIFI was predicted by older age, female sex (at larger temporal asynchronies), and a lower score on the Montreal Cognitive Assessment (MoCA). Our results confirm, in a populationrepresentative sample, that enhanced audiovisual integration is associated with ageing and extend the association between multisensory integration and mild cognitive impairment to global cognitive status. Importantly, the findings also highlight the role of the sex of the participant as a previously overlooked factor in studying multisensory perception in ageing.