This is an invited research digest contributed by Marcus L. Leppanen, M.S. at the University of Louisville.
The most common form of memory that is studied in psychology is memory for events from a person’s life, for instance, their graduation ceremony years ago or the romantic dinner with their partner last night. However, people frequently remember, and forget, that they have already remembered something. It is likely that you have had the experience of telling a friend your story of your graduation ceremony, for instance, but had them abruptly stop you, saying “you already told me that!”
When such a situation occurs, you are having the experience of forgetting that you previously retrieved a memory, despite there are also being plenty of times in which you can remember that you told someone a story before. In the literature, this is known as memory for prior remembering. We, as well as other researchers, are interested in understanding why people forget prior remembering and how we can be better at remembering our previous acts of retrieval.
Previous research has shown that contextual information is associated with the accuracy of memory for prior remembering. Loosely defined, contextual information is the when, where, and how you felt about an event that makes similar experiences distinct from one another in memory. Previous research suggests that changes in semantic context, or word meaning, impairs memory for prior remembering .
This was shown using a three-phase procedure during which participants initially learned a series of cue-target word pairs (e.g., dog – bark), where the first word was the cue and the second word was the target. In memory research, the term “target” is used to identify the information that will be retrieved later. Critically, in this procedure, the target words were homographs and could have two dominant meanings which were signaled by one of two possible cues. For example, bark can be the sound that a dog makes, but it is also part of a tree. For that reason, bark could be cued by either dog or tree. Participants were asked to retrieve most of the targets twice and to indicate, after the second attempt, whether they also retrieved the target during the first attempt.
The results showed that when bark is cued by dog throughout the entire experiment, that participants can accurately remember their previous retrieval of bark. However, when bark is cued by tree first and then by dog, participants can no longer remember that they previously retrieved bark as accurately. In other words, compared to retrieving something in a single context, retrieving something in different contexts makes remembering the retrieval more difficult.
As a real-world example, you may tell a friend a story, while having dinner at their house, about a fun experience that you had at a particular restaurant. Perhaps weeks later, you and that same friend go to the restaurant you had the fun experience at. Being at the restaurant may remind you of the last time you went there and you start telling your friend about your fun experience, only to be interrupted with the reminder that you already told them the story. In that situation, you retrieved your memory for the bad experience at the restaurant in two different contexts. One was your friend’s house and the other was the restaurant. Research suggests that the change in context could be part of why you forgot previously telling the story.
In our laboratory at the University of Louisville, we wanted to explore whether we could reduce, or eliminate the impairment that changes in context have on how accurately we remember our previous retrievals. Using the previously described procedure, we explored whether having participants think about both contexts during the first retrieval could improve their ability to remember that retrieval, even if there was a change in context.
We showed that some participants could remember that bark was initially learned as the sound a dog makes, despite now being tested as part of a tree, while others could not. The participants who were able to remember both contexts were able to remember that they retrieved bark just as well as participants who only saw bark paired with dog throughout the experiment .
Our results suggest that experiencing an event, retrieving a memory for that event, and remembering that you retrieved a memory for that event, are all intertwined. Specifically, remembering the context in which an event was experienced, when you try to remember it for the first time, can make it easier to also remember that act of retrieval later on. Remembering previous contexts would be particularly helpful when you retrieve a memory in a situation that closely resembles the initial event. The greatest benefit comes from actively searching for the previous context in your memory, rather than being given that information from someone else.
Thus, one way to reduce the likelihood of experiencing those embarrassing situations when a friend says “you already told me that” could be to attempt to think about the context in which the event you are remembering occurred. That way you can associate the original context with your current retrieval context. It seems plausible that such a strategy would make an act of retrieval more memorable and less likely to be forgotten later.
 Arnold, M. M. & Lindsay, D. S. (2002). Remembering remembering. Journal of Experimental Psychology: Learning, Memory, and Cognition, 28, 521-529.
 Leppanen, M. L. & Lyle, K. B. (2018). Making remembering more memorable. Memory, DOI: 10.1080/09658211.2017.1422270