In everyday language, the way we talk about memories implies they’re something like snapshots that are somewhat stored in some sort of album in the brain.
If that were the case, we would be able to remove a very specific bad memory, the same way we can remove a photo from an album. Or we could conceivably transplant memories into other people.
But this is no more possible than it is possible to transplant a palm tree to the Arctic, or a ski slope to Las Vegas. A palm tree or a ski slope don’t exist in isolation, they’re rooted in an ecosystem. A memory is also deeply rooted in an ecosystem.
For one thing, a memory is not a neutral snapshot of what happened, independent of how the experience affected us. A memory is the trace that an experience leaves in us: It includes both factual information about the event, and our reaction to it. This is coded in the sequence of neural connections that correspond to our reaction (i.e. the somatic markers of the emotional emotions and motions).
Because the memory is not just a neutral snapshot, but also a “script” of how we react, it has the capacity to change when we look at it again, under new circumstances. In fact, this is what makes healing possible: We change our perspective. We do not go back to facing the traumatic experience from a narrow, isolated perspective where we are overwhelmed. We create a resourcing environment, a broader container, within which the experience can be “digested”.
In other words: We can’t remove the memory and do as if the experience never happened, but “digesting” it means that we are nourished by it, and stronger for it. As we overcome the effects of stress, we build resilience.
See also: What is stress? What can we do about it?