Long-term maintenance of infant memory.

The present experiments with human infants asked whether periodic nonverbal reminders could maintain a memory established at 2 months of age over a substantial period of development. In Experiment 1, a reactivation reminder recovered infants' forgotten memory after 3 weeks, but a reinstatement reminder did not. In Experiment 2, 2-month-olds received a reminder every 3 weeks through 6(1/2) months of age and a final test at 7(1/4) months of age. A preliminary retention test preceded each reminder; which type of reminder (reinstatement or reactivation) infants received depended on performance during this test. Infants exhibited significant retention 4(1/2) months later, and most remembered 5(1/4) months later, when infants outgrew the task. Untrained controls exhibited no retention after any delay. These data confirm that periodic reminders can maintain early memories over significant periods of development and challenge popular claims that preverbal human infants cannot maintain memories over the long term because of neural immaturity or an inability to rehearse experiences by talking about them. Copyright 1999 John Wiley & Sons, Inc.