The reach of reactivation: Effects of consciously triggered versus unconsciously triggered reactivation of associative memory

Amir Tal, Eitan Schechtman, Bruce Caughran, Ken A. Paller, Lila Davachi

Research output: Contribution to journalArticlepeer-review

2 Scopus citations

Abstract

Consolidating memories for long-term storage depends on reactivation. Reactivation occurs both consciously, during wakefulness, and unconsciously, during wakefulness and sleep. While considerable work has examined conscious awake and unconscious sleep reactivation, in this study, we directly compare the consequences of conscious and unconscious reactivation during wakefulness. Forty-one participants learned associations consisting of adjective–object–position triads. Objects were clustered into distinct semantic groups (e.g., fruits, vehicles) such that we could examine consequences of reactivation on semantically related memories. After an intensive learning protocol, we systematically reactivated some of the triads by presenting the adjective as a cue. Reactivation was done so that it was consciously experienced for some triads, and only unconsciously processed for others. Memory for spatial positions, the most distal part of the association, was affected by reactivation in a consciousness-dependent and memory-strength-dependent manner. Conscious reactivation resulted in weakening of semantically related memories that were strong initially, resonating with prior findings of retrieval-induced forgetting. Unconscious reactivation, on the other hand, selectively benefited weak reactivated memories, as previously shown for reactivation during sleep. Semantically linked memories were not impaired, but rather were integrated with the reactivated memory. These results taken together demonstrate that conscious and unconscious reactivation have qualitatively different consequences. Results support a consciousness-dependent inhibition account, whereby unconscious reactivation entails less inhibition than conscious reactivation, thus allowing more liberal spread of activation. Findings set the stage for additional exploration into the role of conscious experience in memory storage and structuring.

Original languageEnglish
Article numbere2313604121
JournalProceedings of the National Academy of Sciences of the United States of America
Volume121
Issue number10
DOIs
StatePublished - 5 Mar 2024
Externally publishedYes

Bibliographical note

Publisher Copyright:
© 2024 the Author(s). Published by PNAS.

Keywords

  • consciousness
  • inhibition
  • memory consolidation
  • memory reactivation

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