Associative memory persistence in three- to five-year-olds.

Abstract

Adults struggle to recollect episodic memories from early life. This phenomenon - referred to as infantile and childhood amnesia - has been widely observed across species and is characterized by rapid forgetting from birth until early childhood. While a number of studies have focused on infancy, few studies have examined the persistence of memory for newly learned associations during the putative period of childhood amnesia. In this study, we investigated forgetting in 137 children ages three- to five-years-old by using an interactive storybook task. We assessed associative memory between subjects after five-minute, 24-hour, and one-week delay periods. Across all delays, we observed a significant increase in memory performance with age. While all ages demonstrated above-chance memory performance after five-minute and 24-hour delays, we observed chance-level memory accuracy in three-year-olds following a one-week delay. The observed age differences in associative memory support the proposal that hippocampal-dependent memory systems undergo rapid development during the preschool years. These data have the potential to inform future work translating memory persistence and malleability research from rodent models to humans by establishing timescales at which we expect young children to forget newly learned associations.