The development of declarative memory in human infants: age-related changes in deferred imitation.

In 2 experiments, deferred imitation procedures were used to trace age-related changes in declarative memory by human infants over the first 2 years of life. An adult modeled 3 actions with an object, and infants' ability to reproduce those actions was assessed 24 hr later. Some infants were tested with a new object or in a new context relative to the original demonstration. Changes in the context disrupted the performance of 6-month-olds but had no effect on the performance of 12- and 18-month-olds. Changes in the object disrupted the performance of 6- and 12-month-olds but had no effect on the performance of 18-month-olds. This age-related increase in representational flexibility may account for the decline of childhood amnesia during the 3rd year of life.