Child-directed action promotes 2-year-olds' imitation.

Children are voracious learners and adults are ubiquitous teachers. This project investigated whether the special infant-directed action modifications parents use when teaching their children (called "motionese" by Brand et al., Developmental Science, 2002, Vol. 5, pp. 72-83) improves 2-year-olds' imitation. Children saw an adult perform a series of acts on four novel objects using either an infant-directed style (including larger range of motion and enhanced boundary marking) or an adult-directed style. Children's imitation of the acts was higher in the infant-directed condition relative to the adult-directed condition, and both types of demonstration increased imitation relative to baseline (no demonstration). We propose that motionese provides information about actions, objects, and intentionality, thereby enhancing toddlers' observational learning.