We often imagine memories as files stored permanently in the brain once created, they simply remain there waiting to be retrieved. Neuroscience suggests something much more complicated. When a memory is recalled, it can temporarily become flexible again, creating an opportunity for that memory to be altered before it is stored once more. This process is known as memory reconsolidation.
The concept challenges the idea that remembering is simply replaying a fixed record of the past. When we retrieve a memory, the neural representation associated with it may enter a temporarily unstable or “labile” state. It then has to be stabilised again through reconsolidation. During this window, new information can sometimes become incorporated into the memory.
One reason this can happen is prediction error the experience of something not matching what we expected. For example, imagine that you have a strong memory of being afraid of a particular situation. If that memory is reactivated and you subsequently experience the situation without the expected negative outcome, the mismatch can provide a signal that the original memory needs updating. Researchers have found evidence that prediction error can help make certain memories more susceptible to modification.
Importantly, this does not mean scientists can simply erase a memory like deleting a computer file. Memory modification is highly dependent on the type, age and strength of the memory and on exactly how it is reactivated. Studies in humans have produced promising findings, but results have also been inconsistent, and some apparent memory changes may reflect new learning rather than actual alteration of the original memory trace.
Researchers are particularly interested in reconsolidation because it could potentially help modify maladaptive emotional memories, including memories associated with fear, trauma and addiction. Instead of attempting to eliminate a memory completely, scientists are investigating whether its emotional impact can be reduced by introducing new information while the memory is temporarily susceptible to updating.
But there is a fascinating implication beyond clinical applications: memory may be naturally designed to change.
A perfectly unchanging memory would not always be useful. The world changes, circumstances change, and information learned today may need to modify what we remember from yesterday. Memory updating may therefore be a feature rather than a flaw: a biological mechanism that allows past experiences to remain relevant to present circumstances.
Could a memory therefore be changed without you realising it?
Potentially, yes but not in the science-fiction sense of someone secretly rewriting your memories at will. Ordinary remembering itself can sometimes alter how information is subsequently represented or retrieved. The process is subtle, conditional and still being investigated. Your memories may feel like records of the past, but biologically, remembering may be part of rewriting them.
Sources:
Elsey, J. W. B., van Ast, V. A., & Kindt, M. (2018). Human memory reconsolidation: A guiding framework and critical review of the evidence. Psychological Bulletin, 144(8), 797–848. https://doi.org/10.1037/bul0000152
