Picture yourself in the driver’s seat of a car, spiraling out of control, pitching over the lip of a ditch, knowing as it happens that you were going a little too fast on the ice. You are tossed, casually, like a body turning as it meets a wave. The windshield fills with snow, bursts of powdery fluff, the kind you’d play in with your brothers and sisters when you were young, flakes glittering as they floated past your eyelashes to the ground. Instead, those specks are glass, sparkling shards twinkling around your hair, speckling your arms, which are clutched around your head, cradling your brain from the impact. You land upside down, hanging by a seatbelt in mid-air, a shaken mess of brittle glass and bone surrounded by crunched steel. When you replay the scene in your mind, the windshield shatters as it meets the snow. You can hear the crack. It broke. Didn’t it? Now, after so many years, you don’t know for sure. You think so, but you don’t have the cuts to prove it. Imagine that every single time since, your foot pushes the gas pedal and this memory replays in your head. Now imagine someone told you that you could forget it, forever.

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When Karim Nader was a 33-year-old graduate student at New York University in 1999, he had the eureka moment most neuroscientists only dream of. He’d bet a bottle of tequila on the results of a study his supervisor, Joseph LeDoux, was convinced would fail. Nader, whose background wasn’t in memory, wanted to challenge a long-held tenet of the field. Recollections, once built into the brain, were thought to be virtually unchangeable. But that theory didn’t line up with studies showing that rats’ memories could be disrupted with painful shocks or drugs. So Nader set up his own experiment: he trained four rats to expect an electric shock after a high-octave beep was emitted. Twenty-four hours later, he injected the animals with a drug that prevents the brain’s pathways from producing new proteins. If memories were unalterable, the rats would react the same way as they had the day before. They didn’t. Instead of freezing after they heard the beep, the rats acted utterly unfazed, like nothing had happened. Nader’s theory? We rebuild memories each time we access them. His finding rocked the academic world—scientists wrote journal articles trying to debunk his discovery. Some ignored him outright at conferences. But as other studies confirmed what he’d discovered, the field of research exploded.

What happens when that rewiring—reconsolidation, as it’s known academically—becomes a less organic process? All over the world, white coats in laboratories are trying to determine how to make ideas similar to the ones explored in 2004 cult classic Eternal Sunshine of the Spotless Mind a reality. In the film, Clementine and Joel (played by a neon-tressed Kate Winslet and a serious Jim Carrey) each visit a clinic to undergo a medical procedure to erase the memories of their relationship once it disintegrates. Although no such facility exists in our world, scientists have developed drugs to eradicate memories we associate with feelings of fear. One scientist, Merel Kindt, at the University of Amsterdam used beta-blockers, pills usually prescribed to patients with heart disease, to successfully destroy a fear of spiders her team had cultivated in its subjects in previous days. But trauma created in a lab can’t mirror longstanding, irrational phobias, so the next logical step for the group was to test the drugs (40 milligrams of propranolol) on actual arachnophobes. In the study, set to be published in Biological Psychiatry later this year, the researchers exposed their volunteers to a live tarantula for two minutes to see who freaked out and who, after ingesting the propranolol, didn’t register a strong reaction. The experiment worked.

Also last year, a paper in the journal Nature described researchers from the Netherlands using electroconvulsive therapy to successfully stop the brain from reconsolidating memories. The doctors sat 42 depressed patients down to watch slideshows of two emotionally traumatizing events, a sexual assault and a car crash. The following week, those patients were split into three groups to test their memories. One contingent was tested a day after receiving electroshock therapy, a second 90 minutes after and a third tested just based on what they’d seen the week before, with no neural tampering. The results were pretty insane: the researchers found the first group’s recall to be no different from “chance level”—like they’d never witnessed the traumas at all.

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Last year, Stanford University School of Medicine genetics professor Dr. Hank Greely, who’s also the school’s director for the centre for law and biosciences, told The Atlantic that he thinks it’s within the realm of possibility that in 10 to 20 years, we’ll be able to pinpoint and delete entire memories. But to what degree do our memories define who we are? “Memories make up our identity, including our personalities, and in some important ways, we are our memories so if we lost or changed our memories we would be different people,” he said.

Of course, the positive implications of this work could be great: Daniela Schiller, a prolific researcher in New York who runs the Mount Sinai School of Medicine’s affective neuroscience lab, is trying to discover a way out of the pain for PTSD sufferers like her father, who survived the holocaust. As she explains in a recent New Yorker profile of her work, “I want to disentangle painful emotion from the memory it is associated with. Then somebody could recall a terrible trauma, like those my father obviously endured, without the terror that makes it so disabling. You would still have the memory, but not the overwhelming fear attached to it. That would be far more exciting than anything that happens in a movie.” For those tortured by flashbacks of their psychological wounds—abuse, addiction, anxieties, anything that cripples them with fear—it could mean release.

Many of us are lucky enough to avoid the festering traumas, the ones that split your guts open and splatter them on the walls over and over, the ones we turn into art. I have been lucky. But we all live in fear of hurt or betrayal, the pinpricks people leave on our hearts that can turn into scars. It’s those micro hurts that we face that made Eternal Sunshine so relatable. Two weeks ago, I sat in a friend’s car, the Montreal deep freeze creeping in, as she reflected on a boyfriend’s recent infidelity. Why couldn’t she have something like the memory-zapping pen used by Tommy Lee Jones and Will Smith in Men in Black, to obliterate not just the feelings of pain, but the ones of love and care that she still felt, irreconcilably, alongside them? She was desperate to relieve herself of the frenzy of her own mind. For her, the pen wouldn’t help, not really. The memories are a lesson in watching more closely for signs, to avoid ignoring the red flags next time. A child learns a knife is sharp by making the mistake of cutting their finger. For me, once veering off the road now keeps me on it.

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Our memories make us human; instinct and science tell us so. They’re inextricably linked to our identities and imaginations. We’re decades beyond the question of whether or not memory alteration is an area of research worth pursuing. Does eliminating the feelings of terror that keep me, or anyone, up at night mean freedom from our mental prisons? Imagine that, in a decade or two, we’re able to isolate, adapt and slowly dull our memories. Imagine all the world’s atrocities indexed on a spectrum—everyone whose suffering ranks five or higher gets access to the memory drug. Imagine us a little more numbed to our sadness. Imagine someone with the resources—a government, a military, a hostile enemy—buying up the world’s supply. And then what? Dystopian, sure, but not impossible. If you can splice a memory, can you embed a new one? Can you rationalize the sickest of historical events by deleting someone’s feelings? We are already masters at manipulating our own minds. Won’t we lose ourselves?

Also read: Lauren Quinn on how our minds rewrite history—and what we do with all we’ve forgotten.