The Development of Rational Imitation in 9‐ and 12‐Month‐Old Infants

Studies on rational imitation have provided evidence for the fact that infants as young as 12 months of age engage in rational imitation. However, the developmental onset of this ability is unclear. In this study, we investigated whether 9‐ and 12‐month‐olds detect voluntary and implicit as well as nonvoluntary and explicit constraints in the head touch task. Three groups of infants watched video sequences, which displayed a person illuminating a lamp using the head. The hands of the model were either free, occupied by voluntarily holding a blanket, or nonvoluntarily restrained by being tied to the table. An additional control group of infants watched the model turning on the lamp by using the hand. Given that the majority of infants imitated the head touch when the model's hands were free, there was evidence for rational imitation in comparison to the condition in which the model's hands were tied to the table, but not in comparison to the condition in which the hands were occupied by holding a blanket. Nine‐month‐olds showed no differences in their behavior according to the condition. These findings clarify the onset of rational imitation by showing that 12‐month‐olds (but not 9‐month‐olds) take into account a situational constraint only when the constraint is nonvoluntary and explicit.     

Means‐End Behavior in Young Infants: The Interplay of Action Perception and Action Production

In 2 experiments, the interplay of action perception and action production was investigated in 6‐month‐old infants. In Experiment 1, infants received 2 versions of a means‐end task in counterbalanced order. In the action perception version, a preferential looking paradigm in which infants were shown an actor performing means‐end behavior with an expected and an unexpected outcome was used. In the action production version, infants had to pull a cloth to receive a toy. In Experiment 2, infants' ability to perform the action production task with a cloth was compared to their ability to perform the action production task with a less flexible board. Finally, Experiment 3 was designed to control for alternative low‐level explanations of the differences in the looking times toward the final states presented in Experiment 1 by only presenting the final states of the action perception task without showing the initial action sequence. Results obtained in Experiment 1 showed that in the action perception task, infants discriminated between the expected and the unexpected outcome. This perceptual ability was independent of their actual competence in executing means‐ end behavior in the action production task. Experiment 2 showed no difference in 6‐month‐olds' performance in the action production task depending on the properties of the support under the toy. Similarly, in Experiment 3, no differences in looking times between the 2 final states were found. The findings are discussed in light of theories on the development of action perception and action production.