Evidence for a Generic Process Underlying Multisensory Integration

It has been shown repeatedly that the various sensory modalities interact with each other and that the integra- tion of incongruent percepts across two modalities, such as vision and audition, can lead to illusions. Different individual cognitive features (i.e., attention, linguistic experience, etc.) have been shown to modulate the level of multisensory integ- ration. As such, it may be hypothesized that an intra-individual generic process underlies parts of illusory perception, irre- spective of illusory material. One simple way to address this issue is to assess whether observers experience multisensory integration to a similar degree when the illusory material varies with respect to its sensory features. Here, performance on two distinct audio-visual illusions (McGurk effect, illusory flash effect) was tested in a group of adult observers. Results show a positive within-subject correlation between both illusions indirectly supporting the existence of a generic process for multisensory integration that could include individual differences in attention.