Evidence for children's online integration of simultaneous information from speech and iconic gestures: an ERP study

Children perceive iconic gestures, along with speech they hear. Previous studies have shown that children integrate information from both modalities. Yet it is not known whether children can integrate both types of information simultaneously as soon as they are available (as adults do) or whether they initially process them separately and integrate them later. Using electrophysiological measures, we examined the online neurocognitive processing of gesture-speech integration in 6- to 7-year-old children. We focused on the N400 event-related potential component which is modulated by semantic integration load. Children watched video clips of matching or mismatching gesture-speech combinations, which varied the semantic integration load. The ERPs showed that the amplitude of the N400 was larger in the mismatching condition than in the matching condition. This finding provides the first neural evidence that by the ages of 6 or 7, children integrate multimodal semantic information in an online fashion comparable to that of adults.