Suppressing Unwanted Memories Reduces Their Unintended Influences

The ability to control unwanted memories is critical for maintaining cognitive function and mental health. Prior research has shown that suppressing the retrieval of unwanted memories impairs their retention, as measured on intentional (direct) memory tests. Here we review emerging evidence revealing that retrieval suppression can also reduce the unintended influence of suppressed traces. In particular, retrieval suppression (1) gradually diminishes the tendency for memories to intrude into awareness, and (2) reduces memories’ unintended expressions on indirect memory tests. We present a neural account in which, during suppression, retrieval cues elicit hippocampally-triggered neocortical activity that briefly reinstates features of the original event, which, in turn, are suppressed by targeted neocortical and hippocampal inhibition. This reactivation-dependent reinstatement principle could provide a broad mechanism by which suppressing retrieval of intrusive memories limits their indirect influences.