The forgetting of newly acquired and reactivated memories of 3-month-old infants

Abstract

Three-month-old infants were trained to produce movement in an overhead crib mobile by footkicking in a standard mobile conjugate reinforcement paradigm. Thirteen days following the conclusion of training, when forgetting was complete, infants received a direct reactivation treatment consisting of a brief noncontingent exposure to the reinforcer. Not only did the reactivation treatment arrest forgetting and restore conditioned responding of infants tested as long as 3 days after the reminder, but also the forgetting function of the reactivated memory, which was obtained from independent groups tested 1, 3, 6, 9 and 15 days after the reactivation treatment, had the same form and slope as the forgetting function of the newly acquired memory. These data confirm the efficacy of a reactivation treatment in alleviating forgetting, and demonstrate the relatively broad time span over which a single, brief reminder can facilitate retrieval in very young infants.