Abstract
To reduce sensory uncertainty and reach a decision, the brain can use sensory combination and acquired knowledge. Whereas adults can reduce uncertainty by combining sensory estimates, in recent studies children below 8 years failed to do so. Here we ask whether children’s multisensory processing is sensitive to prior knowledge about cue correspondences. Fifteen adults, thirteen 10-11, and fourteen 7-8 year-old children gave simultaneity judgments (SJ) and temporal order judgments (TOJ) for audiovisual displays with varying degrees of synchrony. We compared stimuli in which prior knowledge predicts a low (beep-flash) vs. a high (face-voice) degree of audiovisual correlation. Psychometric functions were fitted to proportions of ‘simultaneous’ (SJ task) and ‘vision first’ (TOJ task) responses in order to measure observers’ temporal integration windows (TIWs) across tasks and stimuli. We interpret a larger TIW in the TOJ compared with the SJ task as indicating mandatory integration of estimates, as reflected in an impaired ability to judge which came first (despite an ability, in the SJ task, to judge whether they were simultaneous ͨ2;Hirsh, 1961). Overall, TIWs reduced with age: children were less sensitive than adults to audiovisual asynchrony. Differences in the size of TIW for SJ vs. TOJ tasks also significantly decreased with age, indicating that children were more subject than adults to mandatory integration of estimates. Across ages, the TOJ-SJ difference was greater for face-voice than flash-beep stimuli, showing that children, like adults, were affected by prior knowledge about cue correspondences. Finally, correlation analyses revealed that children’s sensitivity to audiovisual asynchrony across the two tasks was correlated, while, in line with previous findings, the sensitivity of adults was not (van Eijk, Kohlrausch, Juola, van De Par, 2008). Together these results indicate that while prior knowledge affects multisensory integration from early childhood, with age more specific task-related multisensory mechanisms emerge.
Meeting abstract presented at VSS 2013