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Issue 13 Science (of) Fiction

From Obliviate to Neuralyzers – erasing and modifying memories

🕒 6 min

“Hermione! The tea is ready, darling!”

“Coming, mum!”

In the next frame we can see Hermione, portrayed by Emma Watson in the movie Harry Potter and the Deathly Hallows: Part 1, coming down the stairs behind her parents’ back, pointing her magic wand towards them and saying the word Obliviate. I am guessing every Harry Potter fan reading this just experienced shivers down their spine, but for those who are not familiar with this book series and the movies that followed, Hermione just erased all memories of her from her parents’ minds.

You can watch the scene here for yourselves:

We can see Hermione disappearing from family pictures, which is just a nice way of depicting that her parents are not aware of her existence anymore. They continue living their lives as if they had never had a daughter. But is something like this actually possible? Can we somehow make people forget some events on purpose? Or even better, plant fake memories? This can be seen in various SF movies and comic books, like in Men in Black, where agents use the Neuralyzer to plant a fake memory inside a person’s mind when they have seen something they should not have seen. How plausible is this in real life?

Is erasing memories possible?

The process of erasing memories (or forgetting, which would be a layman’s term) is crucial for our everyday life. Imagine being able to remember everything you have ever read, seen, heard, smelled, and tasted – probably sounds fun? Then imagine being able to remember everything bad that happened to you or someone close to you? It starts to suck quickly, don’t you agree?

Our brains function on a simple principle – “use it or lose it” – if a memory is not used for a while, the synapses which form this memory degrade and disappear. If you wish to learn more about how we form and keep memories, take a look at one of my previous posts where I go into detail about it.

This enables us to pile up the important stuff in our brains and get rid of the unnecessary junk. This is frequently seen in people who have had traumatic experiences in their childhoods. When an event generates an immense amount of stress in a person’s life, their brain resorts to powerful mechanisms to prevent the destabilization of their mental status. These mechanisms are called defence mechanisms, and they help us process events like that on a subconscious level. One of these mechanisms is called repression, where a person forgets about the circumstances of an event or even whole events or periods in their life because they were very stressful. Sometimes this can cause dissociative amnesia, a condition where a person cannot remember important information about their life.

As you can see, we have the necessary mechanisms in our brains to forget, there are only a few questions standing: can we somehow make this happen in anyone we want? And when should we use it?

When can memory erasing be useful?

The first thing that popped into my mind when thinking about this problem is helping people with phobias – immense irrational fears of, say, heights, or closed spaces, or spiders. Also, this could help people who were not able to forget something very stressful in their life who wish that they could. We could also think outside the box – what if we could help people entering stressful situations, like soldiers, become less prone to remembering those stressful events while being completely able to function during them?

This of course raises various ethical questions, which you have possibly already asked yourselves. Personally, I am very interested in the question of whether we would stay the same person after our memories were erased? Imagine if some of the most important events in your life suddenly disappeared from your memory. Wouldn’t it change the way you acted? And the way you thought about something?

Also, an additional problem (especially with the soldier example) would be the dehumanization process. Imagine being able to commit a crime and then forgetting that you even did it. Or how about erasing the stressful aspect of it so it seems like you read about it in a book? To me, it seems like erasing something inherently human – our conscience.

If you think of any other ethical problems, feel free to comment! I would like to hear your thoughts about this.

How can we actually erase memories?

Just the outright targeted erasing of memories which we can see in the movies Eternal Sunshine of the Spotless Mind, Harry Potter or Men in Black is still impossible in humans. The processes involved in forming memories and forgetting are not well understood enough for us to just go and inject a “forgetting compound” into our brain or use electroconvulsive therapy to zap our bad memories out of existence. Well, at least targeted memory erasure is impossible. If you wish to cause general short-term amnesia, just hit a person in the head with something very heavy. They probably will not remember what happened and why they fell to the ground, but they will still remember their name, dreams, and problems.

However, a lot of work is being put into doing the next best thing – learning to cope with bad memories. Cognitive behavioral therapy is one of the better-known types of psychotherapy for various conditions ranging from phobias and anxiety to eating disorders and PTSD. The main premise of cognitive behavioral therapy is that, by identifying the source of the problem and changing our perception of it, we can change our behavior and mood.

On the other hand, a promising result from Jürgen Sandkühler and Jonathan Lee came in 2013 when they published their paper “How to erase memory traces of pain and fear”, which showed that (in animals) they were able to erase memories of fearful and painful events. One particular substance they used is Zeta inhibitory peptide (ZIP), which has been shown to erase long-term memories in various animal models, from cockroaches to mice, by reversing the mechanism of learning.

Another interesting way of erasing memories (and potentially modifying them) is optogenetics paired with deep brain stimulation – an invasive neuromodulation technology which uses light to control the activity of individual neurons.

Modifying memories

For the end, I wanted to touch on modifying memories. The subject of modifying memories is very controversial, especially since a lot of people claim that they can do it. They are calling themselves “memory hackers” and they say that implanting false memories is surprisingly easy. Some rely on confusing people so that they cannot find the difference between a real event and a made up one. Others just ensure that a person repeatedly pictures the event happening until it is rooted in their memory.

Optogenetics is also being used in animal models to modify various aspects of memories like the valence (are they perceived as happy or sad) or their consolidation (how long to they stay in your brain). A lot can be said about this new technology, but for now just know that it has showed results in animals!

Final remarks

As always, authors of comics, books, and movies take existing science and they extrapolate what humans could be able to do with them. The same happened here with memory erasing and modifying, which is a very compelling and frequently used subject of various fictional media. Just be sure to remember that the future is coming and a lot of what was science fiction a long time ago is now a reality!


By Mario Zelić

Mario is a medical student with a finite amount of time and an infinite number of hobbies which he tries to squeeze into his everyday life.

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