Haptic information facilitates audiovisual size perception in children but not adults: An ERP study in support of the developmental cross-calibration theory

Several behavioural studies have shown that, while adults integrate sensory information in a statistically optimal fashion, children as old as 8– 10 years exhibit sensory dominance. When discriminating object size for example, young children rely more on haptic than visual or auditory information (Gori et al., 2008; Petrini et al., 2014). However, evidence in support of this sensory dominance at the neural level is scarce. Here we present an ERP study looking at the differences in multisensory processing between children and adults using active touch to perceive object size. We asked 10 adults and 10 children to attend to a wooden ball stimulus while we recorded their neural activity using electroencephalography (EEG). They either had to listen to the sound of the ball, passively look at the ball being tapped while listening to its sound or look at and actively tap the ball while listening to its sound. Here, the sound either matched the size of the presented ball (congruent, e.g. big ball with loud sound) or not (incongruent, e.g. small ball with loud sound). A temporal analysis of ERPs at the mid-parietal channels revealed significant differences in processing patterns between adults and children. We found a significant interaction of age and congruency in the P2 (area and peak amplitude), N2 (area and peak amplitude), and N1 (peak amplitude) components when active touch was involved. When no active touch was involved we found a significant interaction only in the P2 component. The results indicate that touch facilitates object size perception in children by reducing the level of neural activity only in this group when audio and visual information disagreed. These findings support Gori et al.’s (2008) cross-calibration theory by which the more robust sense in a given task (touch here) calibrates the less robust senses in young children.