Reconsolidation of episodic memories: a subtle reminder triggers integration of new information

Abstract

Recent demonstrations of "reconsolidation" suggest that memories can be modified when they are reactivated. Reconsolidation has been observed in human procedural memory and in implicit memory in infants. This study asks whether episodic memory undergoes reconsolidation. College students learned a list of objects on Day 1. On Day 2, they received a reminder or not, and then learned a second list. Memory for List 1 was tested immediately on Day 2 (Experiment 2) or on Day 3 (Experiment 1). Although the reminder did not moderate the number of items recalled from List 1 on either day, subjects who received a reminder incorrectly intermixed items from the second list when recalling List 1 on Day 3. Experiment 2 showed that this effect does not occur immediately and thus is time-dependent. The reminder did not affect memory for List 2 on Day 3 (Experiment 3), demonstrating that modification occurred only for the original memory (List 1). The study demonstrates the crucial role of reminders for the modification of episodic memory, that reconsolidation of episodic memory is time-dependent, and, in contrast to previous reconsolidation findings, that reconsolidation is also a constructive process, one that supports the incorporation of new information in memory.

Figure 1.

Mean percentage of objects correctly and falsely recalled on Day 3 (Experiment 1) in the reminder, the no-reminder, and the interference control group during Experiment 1 (recall test on Day 3). Error bars represent standard errors of means. Note: Participants were asked to recall objects from List 1. Objects that were falsely recalled from List 2 are labeled as Intrusions.

Figure 2.

Mean percentage of objects correctly and falsely recalled on Day 2 (Experiment 2) in the reminder, the no-reminder, and the interference control group. Error bars represent standard errors of means. Note: Participants were asked to recall objects from List 1. Objects that were falsely recalled from List 2 are labeled as Intrusions.

Figure 3.

Mean percentage of objects correctly and falsely recalled from List 2 on Day 3 (Experiment 3) in the reminder and the no-reminder groups. Error bars represent standard errors of means. Note: Participants were asked to recall objects from List 2. Objects that were falsely recalled from List 1 are labeled as Intrusions.