Paradoxical decrease of imitation performance with age in children
AbstractWe studied the development of imitation ability in a cohort of 6-11-year-old children (N=174) with specific attention to error types and their cognitive interpretation. Participants imitated meaningless actions as if they were in front of a mirror (specularly). Actions varied across three levels of complexity (movements of a single limb, arm and leg of the same body side, or arm and leg of opposite sides). Overall performance improved with age. Among the most frequent error categories, side errors (movement imitated with the left instead of the right limb or vice-versa) paradoxically increased with age (from 9 years). Still, their sensitivity to complexity decreased with age. Thus, encoding two opposite body sides has high cognitive costs in younger children and smaller or null costs in older children. We interpreted these results in terms of the enhancement of Working Memory (WM) and body knowledge with age. When WM increases, it paradoxically drives older children to apply their superior body knowledge and imitate anatomically, producing side errors. Younger children are free from such interference because they still lack the necessary body knowledge and WM capacity. In conclusion, this study suggests that anatomical imitation becomes available in childrens cognitive repertoire from age nine due to increased body knowledge and WM capacity. Research HighlightsO_LIThe analysis of error types uncovers/illustrates the role of working memory and body knowledge in imitation. C_LIO_LIAs an effect of little working memory capacity, younger children pay a cognitive cost to encode opposite body sides and make "side errors". C_LIO_LIImitation performance improves with age, but side errors paradoxically increase in frequency due to greater ability to master body knowledge bringing to anatomical imitation. C_LIO_LIAnatomical imitation is available in childrens cognitive repertoire from age 9, as an effect of the development of body knowledge and working memory capacity. C_LI