Here's how a false memory could be planted in your brain

Here's how a false memory could be planted in your brain

Research suggests that your recollections aren’t just worryingly fallible, they’re also surprisingly malleable. So could someone plant a false memory in your mind?

Illustration credit: Matthew Holland

Published: March 16, 2025 at 4:00 pm

What is Darth Vader's most iconic line in The Empire Strikes Back? And how doe the Evil Queen address her mirror in Disney's Snow White and the Seven Dwarfs? Unfortunately, there are no points for the answers "Luke, I am your father" and "Mirror, mirror on the wall."

The actual lines are "No, I am your father" and "Magic mirror on the wall."

But don’t worry if you, like so many, slipped up slightly here. Be it movie quotes or even the details of well- known images like the Monopoly Man’s supposed monocle (he’s never actually worn one), collective misremembering is common. In fact, there’s even a scientific term for it: the Mandela Effect.

The name comes from researcher Fiona Broome who, in 2009, found that many people writing on the internet (including herself) had a memory of Nelson Mandela dying in prison in the 1980s, despite him being released and living until 2013.

False memories appear in our everyday lives, too. It can be different recollections of who agreed to take the bins out or being sure that we’ve locked the front door when actually we haven’t. We’ve all felt certain of something that’s happened, only to have to eat humble pie when proven wrong.

So why does this happen? How can we recollect things so differently from other people – and so differently from what actually occurred? The short answer is our memories are unreliable.

Unlike the episode of Black Mirror where everything is recorded as we live it, we don’t have a perfect playback of our previous actions (thank goodness – I can do without seeing some of my finest moments played back to me). Human memory is fallible.

False memories are memory errors that happen when we remember a past event differently from how it happened: different details, a mash-up of multiple events or even remembering something that never happened. We might think we’ve taken a medication when we haven’t or misremember where we met someone.

More serious examples have historically included worries that people might misremember significant (and potentially abusive) childhood events, if manipulated by others.

Prof Catherine Loveday from the University of Westminster, London, researches normal and impaired memory. She likens the way that two people can end up with different recollections of the same event to cooking: “You both start out with the same ingredients, but one of you makes a spaghetti bolognese and the other makes a chilli.”

Our memory is a limited capacity system and when we have gaps in it, our brain tends to fill those in based on general ideas, which can be different for each of us.

“For most of us”, explains Loveday, “we pull together sights and sounds and feelings, and use a knowledge framework to create the sense of a remembered experience. Imagination does the same thing – when we imagine a future event we’re creating it from the building blocks that we have.

“It’s not that memories are all fictional, but they’re not as accurate as we think they are. We use all sorts of mechanisms to keep them within the bounds of what’s likely.”

The idea that our memories are inaccurate can feel unsettling. We link our sense of self to the narrative of our lives and experiences, so the idea that these are shifting can leave us feeling unsure of ourselves. Particularly when we consider the possibility that other people can influence our memories.

Mind games

Illustration of a person sat at a table with a hot drink, the steam from the hot drink is in the shape of them proposing to the steam of a person from another hot drink.
How can we recollect things so differently from other people? - Illustration credit: Matthew Holland

How does your brain know a memory is real? One thing we do is compare our memories with our knowledge about the world. So, if I have a memory that I saw my grandmother in 2016, but I know that she died before then, I won’t believe that memory, however vivid it might be.

Despite these mechanisms for fact-checking your memory, there are experiments that claim it can be manipulated. In the Deese-Roediger-McDermott false memory paradigm, people are given lists of words and tested for memory of a related word.

For example, if I give you a list with the words ‘tree’, ‘decoration’, ‘tinsel’, ‘cake’, ‘present’ and so on, you might be more likely to incorrectly remember that I also presented you with the word ‘Christmas’.

Explanations as to why vary. Some think that our brains work by getting the ‘gist’ of something, rather than recalling each word precisely. This approach can create a false sense of familiarity with words that fit the general theme, leading us to mistakenly believe we’ve seen them before.

Others propose that our memories operate by activating neural networks associated with related concepts, causing similar ideas to be activated simultaneously, even if the exact word isn’t present.

Similar mistakes happen with familiar visual objects. For example, if people are shown altered images of famous mascots – like Tony the Tiger with a black nose instead of his usual blue, for example – they often don’t notice the change.

Our brains tend to ‘fill in’ details to match what we expect to see, creating a sense of familiarity even when something is off. This is part of how our brains make sense of the world, sometimes inventing details that aren’t actually there.

Misinformation-based experiments get people to remember wrong information presented after an event. Often this can result in reorganisation or misattribution of actual memories. The ‘lost in the mall’ experiment is a classic example of this, where researchers suggest to people that they were lost in a shopping centre as a child.

Two people look through photographs together
Personal details tend to make falsely planted memories seem more familiar - Credit: Thanasis Zovoilis

When people were presented with four memories described by a trusted adult, one of which was a false memory of being lost, a small proportion said they believed this memory to some degree.

Importantly, personal details were provided by family members that made the fictitious memory seem more believable, such as which shops the participants usually visited. Participants were also told that their families remembered the event.

Memory inflation is another memory-influencing technique. In this approach, people are asked to imagine a specific event and later questioned about whether it actually happened. Simply imagining the event makes it feel more familiar, which can create a false sense of recognition. And this increased familiarity leads people to believe the event might have actually occurred.

Some of this research on memory has led to valuable insights into how we should question people in legal settings. Leading questions, which guide someone towards a specific answer, can bias what people say and influence their memory.

Open-ended questions, which could be answered with any response, are better for accuracy. For example, asking “When did you start a conversation with person X?” is more leading than the request “Tell me about what happened.”

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False alarms

While the false memory studies can feel alarming due to their revelation of how open we are to being influenced by others, there are important caveats to bear in mind.

Prof Chris Brewin, from University College London, has spent years researching memory, particularly in relation to psychological trauma. He suggests that false memory research might not go as far as some have concluded.

A man climbing up a brain on a ladder
False memories all seem to follow the same format when studied in experiments - Credit: Feodora Chiosea

In 2016, he reviewed false memory experiments and checked how much the false memories met three criteria: that they created a belief that the event occurred; gave the person a corresponding recollective experience (a memory of the event); and that the person was confident that the memory was true.

Very few experiments succeeded in meeting all three criteria.

In addition, Brewin points out that the ‘lost in the mall’ experiment, where people are convinced that they were lost as a child, depends on very specific procedures: “People are being told that this happened by a highly credible source [their family member] and false memory judgements are being made by the investigators not participants.”

In fact, when asked themselves, participants tend to report less confidence in their own memories than experimenters believe they have.

Brewin thinks that although false memory studies do show our brains are susceptible to elaborating or mixing up events, the idea that random and new memories can be inserted is possible, but much less likely.

This fits with studies showing that people could be manipulated into believing that they got lost as a child, but can’t be made to falsely remember having an enema – something much more intrusive.

Also, some people might be more vulnerable than others to believing false memories. People under the influence of drugs or alcohol, or with existing memory problems, are more at risk (one study suggests creative individuals might be more likely to have memory errors).

The context we’re in is also important.

The risk of false memory creation is greatest when three conditions are met: one, when someone we trust gives additional information that increases plausibility; two, when someone encourages and guides imagery of the event; and three, when someone uncritically accepts the memory recall rather than challenging it.

Just as with any potential source of misinformation, people’s awareness of potential manipulation also has an important impact.

Set the record straight

Neuroscience and cognitive psychology techniques have tried to tease apart if there’s anything neurologically different about false and real memories. It seems hard to tell.

Functional MRI scans of people experiencing false and true memories implicates the hippocampus in differentiation between the two, but also suggests that the hippocampal response is fallible. It doesn’t seem possible to scan someone’s brain and reliably determine whether a memory is true or false.

Eye scanning has been more successful.

Dr Alex Kafkas from the University of Manchester, in the UK, and his colleagues found that when they created false memories using the Deese-Roediger-McDermott paradigm (the lists of words technique mentioned before), they could differentiate between false and true memories by measuring changes in pupil size.

This suggests that brain signals sent to the autonomic nervous system (which controls your pupils) could reveal unconscious elements of memory accuracy. This experiment was carried out in a lab-based setting using simple words, however – very different to the complex memories of everyday life.

Advances in technology and predictive models may change things in the future. But for now, even with a brain or eye scanner, it’s hard for us to know whether our memories are true or not.

The nature of being human is that we all experience the world differently and all remember it slightly differently too. If your memory is functional for your everyday life, this is fine. But if you’re worried about accuracy and want to improve yours, there are some steps you can take.

Total recall

If you want to improve your memory, consider how we encode our memories and how we recall them. Mindfulness (paying attention in the present moment) has been linked to memory and being aware of your life as it unfolds, rather than multi-tasking and being distracted, is one thing you can try to do to improve your chances of recalling what happened later.

You can notice smells, tastes, sights, sounds and tactile sensations. Memory experts also describe consciously associating information with other things (for instance, creating a story or image in their mind that helps to remember a name or series of events).

Research with actors suggests they associate specific physical gestures with parts of scripts.

An illustration of two people sat down looking at photos.
Try to create more records to improve your memory. - Illustration credit: Matthew Holland

We can also think about “rehearsing [memories] and keeping an aide memoire,” says Brewin. Trying to create more records, such as taking photos or videos, can refresh a memory when we want to return to it. These can also act as prompts for conversations with others, which can help us to strengthen the memory of the event.

Loveday agrees about the importance of documenting what’s happening to us. “Write it down straight away,” she says. “When it really matters, almost as soon as you possibly can, write down every detail you can remember so that it becomes your first-hand account.”

We can also help ourselves to recall memories, which is a different process to the encoding of memories. Recall is improved when we have more contextual cues that are like the setting of the original event.

Thinking about what we were doing, what the weather was like, maybe trying to cue in the smells of the memory – all these things can help us to remember more vividly.

To protect ourselves against false memories, we don’t need to eliminate them all – that would be impossible. But it is useful to know that our recollection isn’t perfect. This might help us to guard against potential misinformation, but also makes us more aware of our fallibility, helping ensure we don’t get stuck in rigid beliefs about how right we are.

Brewin thinks we do know this – “There’s no evidence that people think memory is like a video recorder. It’s a red herring.” Nevertheless, we still need reminding sometimes.

If there are memories that we know are likely to be precious to us, we need to actively try to remember them: to pay attention and to work to record and rehearse. If you’re looking for a reason to journal more or to print some photos out for your walls, then this is it. What we revisit is what we remember.

About our experts

Prof Catherine Loveday is a Professor of Social Sciences at the University of Westminster, London. She is the author of the book The Secret World of The Brain and has been published in various journals including International Journal of Geriatric Psychiatry, PLoS ONE and Cortex.

Prof Chris Brewin is an Emeritus Professor of Clinical Psychology at University College London. His work has been published in The British Journal of Psychiatry, Applied Cognitive Psychology and Clinical Psychological Science to name a few journals.

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