Neurophysiological evidence of the gesture enhancement effect on degraded speech in children.
To communicate, people can use speech but also co-speech gestures. Previous studies have shown that adults integrate speech and gesture during comprehension. For children, evidence of gesture-speech integration in degraded speech conditions is only provided on a behavioral level. To provide neural evidence, in the present study 6 and 7-year-old children were presented with videos of an actor producing a verb. Sometimes the speech was clear and sometimes degraded by noise. In addition, half of the videos contained an iconic gesture matching the speech. ERP measures showed that gestures caused a larger N400 than speech only, suggesting more semantic processing effort. However, an expected effect of gestures on degraded speech processing was not found. This could suggest that children’s brains are not yet developed similarly as adults’ brains, but since the present study was very small and the expected tendency is visible, it should be replicated on a bigger scale.
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