Developmental changes in the specificity of memory over the first year of life.

In two experiments with 260 infants between 2 and 12 months of age, we examined how differences between the conditions of encoding and retrieval affect retention. Initially, 9- and 12-month-olds were tested with a different cue (Experiment 1) or in a different context (Experiment 2) after delays spanning their respective forgetting functions. These data were then combined with corresponding data previously collected from 2-to 6-month-olds trained and tested in an equivalent task. The resulting analyses revealed that the specificity constraints on memory retrieval become progressively looser at the extremes of the forgetting function with age. With increasing age, retention was less affected by cue changes after shorter absolute delays and, except at 6 months, by context changes after longer absolute delays. This pattern dovetails with evidence of decreasing specificity in the retrieval cues required for deferred imitation during infants' 2nd year and reveals that the memory abilities of older children evolve gradually from early in infancy.