Updating reactivated memories in infancy: I. Passive- and active-exposure effects

This study examined the vulnerability of infants' reactivated memories to modification. In three experiments, one hundred eight 3-month-olds learned to move a distinctive mobile by kicking. After the operant task was forgotten, its memory was recovered by a reactivation treatment. Immediately afterward, attempts were made to modify the reactivated memory by exposing infants to a novel mobile. Exposing the novel mobile immediately after the reactivation treatment did not affect the reactivated memory (Experiment 1). When exposure to the novel mobile was delayed for 24 hr, the novel mobile temporarily interfered with recognition of the original mobile, but did not modify the reactivated memory (Experiment 2). Only when the contingency was briefly associated with the novel mobile (an active-exposure procedure) was the reactivated memory modified (Experiment 3). These data reveal that infants' recently reactivated memories are surprisingly resistant to updating unless the operant contingency that established the original memory accompanies the new information.