Similarity and inhibition in long-term memory: evidence for a two-factor theory

J Exp Psychol Learn Mem Cogn. 2000 Sep;26(5):1141-59. doi: 10.1037//0278-7393.26.5.1141.


Recalling a past experience often requires the suppression of related memories that compete with the retrieval target, causing memory impairment known as retrieval-induced forgetting. Two experiments examined how retrieval-induced forgetting varies with the similarity of the competitor and the target item (target-competitor similarity) and with the similarity between the competitors themselves (competitor-competitor similarity). According to the pattern-suppression model (M. C. Anderson & B. A. Spellman, 1995), high target-competitor similarity should reduce impairment, whereas high competitor-competitor similarity should increase it. Both predictions were supported: Encoding target-competitor similarities not only eliminated retrieval-induced forgetting but also reversed it, whereas encoding competitor-competitor similarities increased impairment. The differing effects of target-competitor and competitor-competitor similarity may resolve conflicting results concerning the effects of similarity on inhibition.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Female
  • Generalization, Psychological
  • Humans
  • Inhibition, Psychological*
  • Male
  • Memory*
  • Mental Recall
  • Models, Psychological
  • Practice, Psychological*