Deferred imitation refers to observing a model and replicating important aspects of the model’s behavior after some significant period. Jean Piaget proposed that deferred imitation, along with language, imagery, and symbolic play, is an indication of the symbolic (or semiotic) function. Although Piaget stated that deferred imitation emerges at around 18 months of age, more recent research has indicated deferred imitation for simple behaviors at as early as 6 or 9 months of age, although the complexity of the actions imitated increases with age.
The length of delay over which behaviors can be imitated also increases with age. For example, Andrew Meltzoff (1985) reported that 45% of 14-month-olds and 70% of 24-month-olds were able to defer imitation over 24 hours. Patricia Bauer and her colleagues (2000) assessed imitation over delays ranging from 1 to 12 months. They showed infants a series of three-step sequences; for instance, the model placed a bar across two posts, hung a plate from the bar, and then struck the plate with a mallet. About half of 9-month-olds tested showed imitation of simpler two-sequence actions after a 1-month delay, although these infants required at least three exposures to the events before displaying imitation. Rate of deferred imitation increased substantially for 13-, 16-, and 20-month-old infants, with older infants demonstrating higher levels of performance during each delay interval than younger infants did. In fact, by 20 months, children remembered individual actions for as long as 12 months.
Some have speculated that deferred imitation reflects a nonverbal form of explicit memory. Explicit, or declarative, memory refers to memory that is available to conscious awareness as reflected by tests of recall in verbal children and adults. This is contrasted with implicit, or nondeclarative, memory, which is memory without conscious awareness. Support for the position that deferred imitation reflects a type of explicit memory comes from research with adult amnesiacs. Adults with specific brain damage (usually to the hippocampus) are unable to form new explicit memories, although they are still able to form new implicit memories. For example, after practicing complicated motor tasks for several days, their performance improves substantially, although they have no conscious (i.e., explicit) recollection of ever having performed such tasks before. These brain-damaged patients perform similarly (and poorly) on explicit memory and deferred imitation tasks, suggesting that deferred imitation uses the same memory system as more conventional explicit memory tasks, implying that infants within their first year of life possess at least the rudiments of explicit cognition.
Evidence of deferred imitation as a nonverbal form of declarative memory may be especially important in comparative research with primates, investigating the possible phylogenetic origins of humans’ unique cognitive abilities. Michael Tomasello (2000) has argued that true imitation requires that the observer not simply repeat the model’s actions, but understand the model’s goal, or intention. Evidence of deferred imitation of actions on objects has been observed in chimpanzees (Pan troglodytes), but only those that have been enculturated, or raised by humans, much as children are reared. Moreover, longitudinal research of deferred imitation in enculturated chimpanzees has shown that these abilities increase with age, with older chimpanzees being capable of more complex imitative behaviors, similar to the pattern observed for human infants. These findings suggest that chimpanzees, and possibly the common ancestor of both chimpanzees and humans, possess the rudimentary representational ability for explicit cognition.
Deferred imitation has been recognized as reflecting important cognitive abilities in children, beginning with the work of Piaget. More recent research indicates that the representational skills underlying deferred imitation are found in infants much younger than proposed by Piaget and may be possessed, under certain circumstances, by humans’ closest genetic relative, the chimpanzees.
- Bauer, P. , Wenner, J. A., Dropik, P. L., & Wewerka, S. S. (2000). Parameters of remembering and forgetting in the transition from infancy to early childhood. Monographs of the Society for Research in Child Development, 65(4, Serial No. 263).
- Bjorklund, F., & Bering, J. M. (2003). A note on the development of deferred imitation in enculturated juvenile chimpanzees (Pan troglodytes). Developmental Review, 23,389–412.
- McDonough, , Mandler, J. M., McKee, R. D., & Squire, L. R. (1995). The deferred imitation task as a nonverbal measure of declarative memory. Proceedings of the National Academy of Sciences, 92, 7580–7584.
- Meltzoff, N. (1985). Immediate and deferred imitation in fourteenand twenty-four-month-old infants. Child Development, 56, 62–72.
- Piaget, (1962). Play, dreams, and imitation in childhood.New York: W. W. Norton.
- Tomasello, (2000). Culture and cognitive development.Current Directions in Psychological Science, 9, 37–40.
- Tomasello, , Savage-Rumbaugh, S., & Kruger, A. C. (1993).Imitative learning of actions on objects by children, chimpanzees, and enculturated chimpanzees. Child Development, 64, 1688–1705.