Developmentally enhanced visual reliability reduces susceptibility to the sound-induced flash illusion: Evidence from bayesian causal inference

Multisensory integration depends on binding tendency (the prior expectation that auditory and visual signals share a common cause) and sensory reliability (the precision of unisensory inputs). However, the distinct developmental contributions of these factors to temporal audiovisual integration remain unclear. Using the sound-induced flash illusion (SiFI) and its reverse variant (FiSI) combined with Bayesian causal inference modeling, we compared performance across early school-aged children, mid-to-late school-aged children, and adults. Our findings show that binding tendency remains stable from childhood to adulthood, with no significant differences in prior expectations between age groups. In contrast, adults exhibited significantly lower visual precision than early school-aged children. These results demonstrate that developmental improvements in audiovisual temporal integration primarily reflect enhanced visual reliability rather than changes in binding tendency.