By Stephanie Jeanneret, Anthony Dutcher, Jarrod A. Lewis-Peacock

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We often think of forgetting as a failure of our brain’s normally “functional memory system” that exists to help us remember important details in our lives. To protect against forgetting, we often rehearse what we seek to remember in hopes of preserving the memory. However, this intuitive strategy may not be as beneficial as we might think. Recent research has shown that the retrieval of a memory can actually impair the future recall of related memories. In other words, forgetting may be an unintended consequence of remembering.

This surprising phenomenon has been coined "retrieval-induced forgetting [RIF)". The pioneers of RIF demonstrated this phenomenon with a relatively simple memory paradigm. Participants studied a number of different items belonging to various conceptual categories (e.g. fruits: oranges and apples; and vehicles: cars and trucks). Afterwards, participants practised retrieving a subset of the studied items with help from a retrieval cue that included the category and part of the item itself: e.g., “Fruit: or__” would be a cue to retrieve “orange”. At the end of the experiment, participants’ memory for all studied items was tested.

The researchers found that participants were less likely to remember the non-studied pairs relative to the studied pairs (not a surprising result, given what we know about the benefits of study practice). But, surprisingly, they also found that memory for non-studied items from a category that underwent retrieval practice (e.g., “apple”, when “Fruit: orange” was practised) was worse than memory for items from un-practised categories (e.g., “Vehicle: car”). These findings suggest that while studying can certainly enhance memory for studied items, studying may actually lead you to forget related unstudied items more so than if you hadn’t studied them at all!

Thus, forgetting one item may be a consequence of remembering a related item. Knowing that our memory system operates in this way has significant implications for designing curricula and shaping study habits more efficiently within the education system.

The behavioural consequences of RIF are becoming more widely appreciated, but we still don’t understand how or why the brain gives rise to this forgetting effect. There is growing interest in studying the neural correlates of RIF. Our research in the Lewis-Peacock Lab at the University of Texas at Austin uses functional magnetic resonance imaging (fMRI) to look at people’s brain activity while they perform memory tasks such as the cued-retrieval task outlined above. We are working to better understand the principles of how the brain remembers and forgets, with a specific focus on the role of “neural competition” whereby thoughts and memories interfere with each other and can produce forgetting. Ultimately, our goal is to understand how the brain curates our memories – strengthening some, discarding others – and identifying the consequences this has on our daily experiences.

Bibliography

Anderson, M. C., Bjork, E. L., & Bjork, R. A. (2000). Retrieval-induced forgetting: Evidence for a recall specific mechanism. Psychonomic Bulletin & Review, 7(3), 522-530. ISSN 1069-9384.

Anderson, M. C., Bjork, R. A., & Bjork, E. L. (1994). Remembering can cause forgetting: Retrieval dynamics in long-term memory. Journal of Experimental Psychology: Learning, Memory, and Cognition, 20(5), 1063-1087. ISSN 0278-7393.

Bjork, E. L., & Bjork, R. A. (1996). Continuing influences of to-be-forgotten information. Consciousness and Cognition, 5, 176-196.

Lewis-Peacock, J. A., & Norman, K. A. (2014). Competition between items in working memory leads to forgetting. Nature Communications 5. doi:10.1038/ncomms6768.