Rational imitation declines within the second year of life: Changes in the function of imitation

Cultural learning plays a crucial role in enabling children to fit into their social community by mastering culture-specific habits. Infants learn actions via imitation, and they seem to be sensitive to the context in which a model demonstrates these. They imitate rationally by copying unusual means to achieve a goal more when the model chooses this means voluntarily compared with when some constraints force the model to do so. We investigated the development of rational imitation. In a within-participants design, 18-, 24-, and 36-month-olds (N = 293) observed two unusual actions: Instead of using her hands, a model operated an apparatus by using her head or by sitting on the apparatus. The model did so once with her hands being occupied and once with her hands being free. Besides measuring participants' imitative responses, we analyzed the gaze behavior directed at the model during the response phase of the current study and of 14-month-olds (N = 82) from Gellén and Buttelmann's study (Child Development Research, Vol. 2017, art. 8080649 [2017]). Increasing age was accompanied by an increasing rate of overall imitation across conditions. None of the three older age groups selectively imitated the unusual actions significantly more often in the hands-free condition than in the hands-occupied condition. Thus, rational imitation seems to disappear during the second year of life. Furthermore, there was a significant increase between 14 and 24 months of age and beyond in children's tendency to gaze at the model after reenacting the observed action. Children's gaze behavior indicates that this pattern might be due to a growing underlying social component in early cultural learning.