Reactivation: priming forgotten memories in human infants.

3-month-old infants, trained to produce movement in an overhead crib mobile by footkicking, showed no evidence of remembering the learned association during a cued recall test 14 days later. Infants who received a reactivation treatment 24 hours prior to the 2-week retention test, however, performed at a level not different from that observed immediately following training. A reactivation treatment administered to a group of infants without prior training did not enhance responding during the retention session 24 hours later. Different measures of retention that have previously been used with 3-month-olds were differentially sensitive to the reminder procedure. The finding that forgotten memories can be remembered through a "prior cuing" procedure illustrates that much of the forgetting of young infants may be attributable to failures in retrieval, rather than to failure in encoding or storage (i.e., memory deficits) as has previously been assumed.