Forgetting unrelated episodic memories through suppression-induced amnesia.

Cognitively suppressing the retrieval of an unwanted memory causes its forgetting and, in the meantime, disrupts hippocampal functions. The present study investigated whether retrieval suppression induces virtual amnesia, which disturbs any existing memories that are reactivated in the temporal vicinity but are otherwise unrelated to the targets of suppression. Participants performed retrieval suppression on a set of memories while cues of an unrelated set of memories were briefly presented near in time to the suppression trials. Results showed that retrieval suppression impaired the retrieval of both the directly suppressed content and the reactivated unrelated memory. This amnesic shadow functioned in both the forward and backward temporal directions, and its forgetting effect was revealed by independent cues that were not presented in the shadow. Remarkably, a negative memory could be impaired simply by presenting it between the suppression episodes of an unrelated neutral memory. These findings provide support for systemic influence of retrieval suppression on hippocampal functions and offer a way to disrupt existing episodic memory strategically. (PsycInfo Database Record (c) 2021 APA, all rights reserved).