Imitation of hierarchical structure versus component details of complex actions by 3- and 5-year-olds.

We investigated developmental changes in the level of information children incorporate into their imitation when a model executes complex, hierarchically organized actions. A total of 57 3-year-olds and 60 5-year-olds participated, watching video demonstrations of an "artificial fruit" box being opened through a complex series of nine different steps. Half of each sample observed the same nine steps performed through either of two different, hierarchically organized procedures, whereas half witnessed differing component action details. Children were found to imitate at both levels but were more likely to copy at the higher hierarchical level than at the level of specific action details. Fidelity to hierarchical organization, but not to the imitation of specific detail, increased with age. However, variation in imitativeness across children at one of these levels did not predict imitativeness at the other level.