Contextual updating of infants' reactivated memories.

The ease with which a reactivated memory is updated has major implications for whether or not a prior memory is likely to be retrieved in the future. In three experiments, we explored this problem with nonverbal human infants, whose newly acquired memory of training in a specific context is readily updated by novel contextual information. In Experiment 1, exposing infants to a novel context immediately after a successful reactivation treatment neither impaired their retention in the original context nor facilitated it in the novel exposure one. In Experiment 2, increasing the delay between the reactivation treatment and exposure to the novel context also failed to facilitate retention in the novel test context. In Experiment 3, the reactivated memory was updated when the contingency was briefly experienced in the novel context immediately after the reactivation treatment. Under these circumstances, previously trained infants exhibited retention in the novel context, but infants who had not been trained 3 weeks earlier or whose original memory had not been reactivated exhibited none. The resistance of a reactivated memory to contextual updating unless the new context is predictive apparently buffers infants' memories against revision after long delays by contexts that could be inappropriate.