Effect of keywords on long-term retention

A number of studies have demonstrated the effectiveness of the keyword mnemonic for short-term recall, for example:

  • McDaniel et al (1987) compared the keyword mnemonic with a strategy whereby new vocabulary were studied in a meaningful context. They found immediate recall was significantly better using the keyword strategy, but after a week, recall was comparable using either strategy.
  • Wang et al (1992) compared the keyword strategy with rote rehearsal for learning foreign vocabulary. They found immediate recall was higher using the keyword strategy, but much worse after one week. But note that recall of the keywords themselves was very good - the problem came with recalling the word the keyword was supposed to remind you of.

In the present study, as with the McDaniel study, the keyword mnemonic was compared with the semantic-context strategy, and obscure English words were used. As usual, immediate recall was better for the keyword method, but after two days, recall using the keyword strategy was significantly worse (although, as before, the keyword itself was recalled very well). The same pattern of results was found using foreign vocabulary.

In the next experiment, subjects were given the opportunity to review, either three times or five times. Compared to a control condition (no review), review improved both immediate recall and recall after two days, with the number of reviews making a significant difference (for both strategies). The important finding however, was that the more rapid forgetting of the keyword mnemonic was considerably reduced with repeated reviews (bringing it to the level of recall seen using the semantic-context strategy after five reviews).

The authors' conclusions are interesting. They point out that distinctiveness cues are apparently less durable (less well-remembered over time) than cues that are relational and semantic, and that these results are thus consistent with the view that imagery-based mnemonics produce distinctiveness cues. That is, such strategies make the to-be-remembered items more vivid and concrete.

They suggest that with only a little practice, only the distinctive keyword images are formed. Extended practice is needed to generate images that effectively integrate relational qualities.

Images are only valuable to the extent that they connect otherwise unrelated information (see The myth of imagery).


  • McDaniel, M.A., Pressley, M. & Dunay, P.K. 1987. Long-term retention of vocabulary after keyword and context learning. Journal of Educational Psychology, 79, 87-89.
  • Wang, A.Y., Thomas, M.H. & Ouellette, J.A. 1992. Keyword mnemonic and retention of second-language vocabulary words. Journal of Educational Psychology, 84, 520-528.


Effective use of the keyword strategy requires repeated reviews of the material

Distinctiveness is not as good a cue as more meaningful information

To be effective, imagery-based mnemonics need to use relational images that bring together the to-be-remembered information and all the necessary cues

Wang, A.Y. & Thomas, M.H. (1995). Effect of keywords on long-term retention: help or hindrance? Journal of Educational Psychology, 87, 468-475.