Science fiction author Jo Harkin shares the science of memory alteration which underpins her new novel, Tell Me An Ending
“If you could pick and choose which memories to keep and which to erase, would you do it?”
This isn’t just a thought experiment: it could be a question you find yourself asking in your own life time.
"This isn’t just a thought experiment"
This question is the premise of my first speculative fiction novel, Tell Me An Ending. When I initially had the idea, I thought I’d be operating in the realm of pure sci-fi. My inspirations were Eternal Sunshine of the Spotless Mind and Black Mirror—works of fiction.
Memory removal is a popular theme in books and TV, so my first concern when I started researching my book was to make sure I wasn’t accidentally copying anyone. I was alarmed to find that the toes I was treading on were real toes, owned by scientists. And my main worry became that by the time the book was published, it wouldn’t be science fiction anymore.
How memory works
Until recently, our understanding of memory has been generally unchanged since Plato’s time. It was accepted that memories laid down in the brain didn’t change.
But this belief was dramatically overturned in the early 2000s, when research published by Karim Nader and Joseph LeDoux showed that each time a memory is accessed, the very act of recall makes it vulnerable to change. This is because a memory is physically rebuilt by the brain, synthesised out of proteins—every time it’s remembered. This process is called reconsolidation.
You rebuild a memory every time you remember it
And—disturbingly—the brain doesn’t refer back to the original memory when it does this. Instead, it refers back to the last time you remembered it. Like a photocopy of a photocopy.
What Nader also found is that the conditions of remembering can affect the rebuilding. For example, if you recall a stressful memory when you’re feeling happy and relaxed, the stress of that memory will fade.
"A memory is physically rebuilt by the brain, synthesised out of proteins—every time it’s remembered"
And if you call up a memory while under the influence of a chemical that temporarily blocks protein formation in the brain, the brain can’t rebuild the memory at all, meaning there’s no reference point for it anymore, and the memory…disappears.
Now, at this point it might seem that we’re very close to the world of my novel, in which a selected memory can be completely deleted. But the leap from erasing memories in rats to doing it in humans is a giant one. We can observe that rats have in fact forgotten something, but we can’t know how they feel afterwards.
Altering memories as treatment for PTSD
The discovery of reconsolidation is the basis, however, for current research on how memory can be altered in humans. Which could be particularly useful for people with PTSD.
The problem with PTSD is that these memories are fixed. Every time the person remembers the trauma, they panic. They relive the moment in a state of high fear and anxiety, and the memory stays vivid and unchanging. Getting them into a calm enough state for the memory to become a calmer memory is the challenge. Traditional therapy can work, but researchers have been trialling new methods that utilise our new knowledge of reconsolidation. Studies have been carried out involving propanolol—an anxiety medication—and MDMA, a euphoria-inducing (and currently illegal) drug.
MDMA, typically seen as an illegal party drug, could be useful for treating PTSD
The idea is for people to talk about traumatic incidents while in the calm or happy state created by the drugs. When the brain begins rebuilding the memory, it looks for stress, and finds only calm. The memory is reconsolidated as a calm memory.
Other non-chemical approaches such as EMDR could be said to work on similar principles. The person with the traumatic memory is encouraged to recall it while being distracted by eye movements. Their brain, being busy, isn’t able to give itself over to panic.
Twenty years on from the discovery of reconsolidation, what has emerged is a willingness to experiment with memory alteration, but not with memory deletion. While most of us have experienced the pain or shame of remembering something we wish we could forget, the ethical problem of testing real deletion on real people in real life is insurmountable.
"There is a willingness to experiment with memory alteration, but not with memory deletion"
Furthermore, early evidence discovered by scientists such as David Glanzman—who found that the memories of sea snails can restore themselves after being erased—could fundamentally develop or change our new understanding of reconsolidation.
In my novel, the ethical line on memory deletion has obviously been crossed. Nobody is asking if it should be done: they’re already doing it. The new development in the world of the novel is that memories can be restored. The story follows several different characters who have had their most painful memories erased—and who now are facing the dilemma of whether to get them back. And while I was alarmed at first, the knowledge that this thought experiment may not be not so theoretical after all added an extra layer of fascination to the writing process—and hopefully to the experience of reading.
Jo Harkin is the author of Tell Me An Ending (Penguin)
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