This novel finding by New York University has shown that remembering something old or noticing something new can bias how we process the information that follows it.
The study published in the journal 'Science', suggests that our memory system can adaptively bias its processing towards forming new memories or retrieving old ones based on recent experiences.
For instance, when we walk into a restaurant for the first time, our memory system can both encode the details of this new environment as well as allow us to remember a similar one where we recently dined with a friend.
The results of this study suggest that what we did right before walking into the restaurant can determine which process is more likely to occur.
Specifically, encoding is thought to rely on pattern separation, a process that makes overlapping, or similar representations more distinct, whereas retrieval is thought to depend on pattern completion, a process that increases overlap by reactivating related memory traces.
The researchers saw a potential resolution to this neurological paradox -that the hippocampus can be biased towards either pattern completion or pattern separation, depending on the current context.
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To address this question, the researchers conducted an experiment in which participants rapidly switched between encoding novel objects and retrieving recently presented ones.
The researchers hypothesised that processing the novel objects would bias participants' memory systems towards pattern separation while processing the old ones would evoke pattern completion biases.
Specifically, they were shown a series of objects that fell into three categories: novel objects, repeated objects, or objects that were similar but not identical to previously presented ones.
Participants were then asked to identify each as new (first presentation), old (exact repetition), or similar (not exact repetition). The similar items were the critical study items since they contained a little old and little new information.
The researchers found that participants' ability to notice the new details and correctly label those stimuli as 'similar' depended on what they did on the previous trial.