Can We—and Should We—Erase Painful Memories?

We don’t have an instant “erase and move on” switch for painful memories—yet. But researchers already know how to tinker with memory: they can dull the emotions tied to a memory and, in animals, even turn memories off completely.

What a memory trace is and how researchers change it

The brain stores memory as physical changes called memory traces: patterns of activity in specific groups of neurons or changes in the connections between them. Those traces can strengthen or fade over time—for example during sleep—and they can shift each time we recall an event.
When a memory is recalled, it goes through reconsolidation, opening a short window of a few hours during which the memory can be modified. Researchers have exploited that vulnerability in animal experiments and, to some extent, in clinical studies with people.

From erased neurons to memories you can switch on

Steve Ramirez, now a professor of neuroscience at Boston University, knows firsthand how destructive memories of loss can be. In 2015, while he was a PhD student studying memory manipulation in mice, his close friend and lab colleague, Xu Liu, died suddenly at 37. Ramirez struggled with grief that interfered with his daily life and work. He tried to numb the pain with alcohol and developed a serious dependence.
The turning point came in February 2021, when Ramirez realized he was drinking in the morning and tracking how much he consumed each day. Friends arranged rehab and staged an intervention. He joined group therapy and has been sober since. Ramirez says the memory of Liu stopped being a source of helplessness and became a motivating force for his research.
In 2009, a Canadian team published a headline-making result: they located the neurons that fired when mice associated a sound with a mild electric shock and felt fear. The researchers chemically destroyed those neurons, and the animals stopped freezing when they heard the same sound—as if the fear memory had been erased.
Ramirez calls that work transformational: it showed that memories include certain highly active cells that researchers can identify and target selectively. The authors cautioned, though, that judging whether a memory truly vanished based only on behavior is tricky—absence of evidence is not evidence of absence.
Another method uses optogenetics. In 2012, Ramirez, Xu Liu, and colleagues identified hippocampal neurons that responded to shock and later activated those same cells with light delivered through an optical fiber in a different context. The mice froze in fear even though there was no shock or conditioned cue—it seemed the researchers had switched the memory on by stimulating neurons. Later experiments implanted false memories in mice and showed that researchers can change a memory’s emotional tone—for example, making a negative memory less negative by activating a positive memory at the same time.
In 2022 Ramirez and his team demonstrated that if researchers activate a positive memory during reconsolidation, they can permanently blunt a negative one—and the effect lasted for months.

Does this work in people?

So far, most interventions in humans are noninvasive and far less extreme than those used in animals. Emily Holmes, a professor at Uppsala University, says the mouse work is valuable because it explains basic memory mechanics, like the reconsolidation timing window.
A few approaches already see use or testing in humans:

• Cognitive behavioral therapy (CBT) — helps people reframe negative memories so they feel less threatening. That approach mirrors mouse experiments where activating a positive memory reduced a negative one.
• EMDR (eye movement desensitization and reprocessing) — involves recalling a memory while performing an external task (sounds, tapping, or tracking a moving object) that disrupts reconsolidation and makes the memory less distressing.
• Pharmacological approaches — some drugs can interfere with forming new memories (benzodiazepines, propofol) or might weaken memories during reconsolidation (propranolol, metyrapone). Results so far are mixed.

The ‘Tetris’ trick and fewer flashbacks

Holmes proposed an unexpectedly simple tactic to reduce intrusive visual flashbacks: play Tetris. She noticed that flashbacks are often visual, and playing Tetris activates the same visual brain regions. A focused 20-minute game right after a traumatic image or memory can hijack visual processing and reduce how often those intrusive images recur.
In a randomized trial of ICU nurses during the COVID pandemic, that brief intervention cut flashbacks from about 14 per week to one per week after a month. Holmes and Ramirez see promise in these noninvasive strategies.

What happens if we erase memories

Even if researchers develop a safe way to erase memories in people, that capability raises many thorny questions. Holmes warns about legal risks: if someone loses memory of a crime, how can they testify in court? How would society preserve records of events? Seeking justice often plays a central role in recovering from trauma.
There are psychological risks too. People who have lost memory because of drug-induced blackouts—for example, after Rohypnol use—don’t always recover more easily. Even without explicit recall, the body and mind can remain traumatized, and an incomplete memory can complicate healing.
Painful memories also teach lessons and shape identity. Imagine removing a memory of a failed relationship or a workplace mistake: how would someone learn to make better choices without that experience? Many artistic, cultural, and charitable responses have sprung from suffering. Temporarily dulling a memory can help in some cases, but permanently erasing it might remove opportunities for growth.
Surveys show up to 80% of people would not want any of their memories erased forever. That makes sense: memories help define who we are. For others, whose traumatic memories destroy daily life, memory manipulation could be life-changing. Ramirez himself says he would not want his memories of his friend Xu erased.
“I always knew I did not want those memories to disappear. Solutions shouldn’t be instant—sometimes answers come decades later. I’d like to believe life is long enough for turning points that give the past deeper meaning,” Ramirez said.
Science already shows memory is not a fixed thing: researchers can weaken it, change its emotional tone, or, in animals, switch it off completely. But the right path for people will likely be complicated. The most realistic and balanced options today focus on reducing suffering safely—therapies, behavioral techniques (like the Tetris trick), and cautious drug interventions. Ethical and legal dilemmas remain, so the question of whether we should erase memories must involve society, not just science.
Based on material from BBC Science Focus
Photo: pixabay.com