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Surprising Science

#3: Erase Traumatic Memories (and Achieve Your Own “Eternal Sunshine”)

This idea was suggested by Big Think Delphi Fellow Joseph LeDoux, of the Center for Neural Science and Department of Psychology at NYU.

“Blessed are the forgetful: for they get the better even of their blunders.” When philosopher Friedrich Nietzsche wrote this in 1885, he couldn’t have imagined that one day people might join the blessed ranks of the forgetful simply by swallowing a pill. Yet this may soon be a reality; several studies suggest we may be able to selectively erase human memories in coming years—yes, just like in the movie “Eternal Sunshine of the Spotless Mind”—and NYU neuroethicist S. Matthew Liao tells Big Think that this is a great idea. 

If and when scientists perfect this technology, it will have tremendous potential for blunting painful memories in those suffering from post-traumatic stress disorder, and it may also help to combat addictive urges. Even though there are some ethical considerations that must be addressed, the choice should ultimately be up to the individual, Liao says: “As long as you don’t harm other people, you should be allowed to use these memory modification drugs in order to improve your personal well-being.”
Liao says that some memory modification drugs “may change what you believe to be true about yourself,” but these problems are not so worrying, because small bits of misremembered falsehoods (believing that you had a good holiday so that you can feel more relaxed) don’t affect anyone else.
But how far away is this technology really? Researchers, including NYU psychology and neuroscience professor Joseph LeDoux, have already been able to target and eliminate certain memories in rats. Based on the knowledge that memory formation relies on certain proteins in the brain, LeDoux administered protein inhibitors to rats to see what would happen. “We conditioned a rat to be afraid of a tone,” LeDoux recounted in his Big Think interview. “So, the next day, he hears the tone and he freezes, because that’s how rats express their fear of the stimulus. But immediately after presenting that tone, we give the rat a certain kind of drug…and we test the rat the next day; the memory is no longer present—or at least can’t be accessed.” Next, LeDoux tried administering the protein inhibitors not during memory formation, but when the rat retrieved that memory of the tone at a later time. Again, the result was the same: no more memory. 
LeDoux’s experiment triggered a wave of similar studies. One

researcher, Dr. Ted Sacktor of SUNY Downstate Medical Center in Brooklyn, pinpointed a specific protein in the brain called PKMzeta, which seems vital for long-term potentiation (the strengthening of connections between two neurons, which scientists see as an important mechanism underlying memory). With this in mind, he conducted a new study using rats in an electrified chamber. First the rats were conditioned to avoid areas of the chamber whose floor was electrified, something the rats would never forget. Later the rats were injected which the drug ZIP, which interferes with PKMzeta, causing them to forget which parts of the floor were electrified; in other words, these long-term memories had been wiped clean. This discovery challenged the prevailing view that memories were a structural mechanism and could not be erased chemically. 

Meanwhile, studies in humans have successfully softened the negative emotions attached to certain memories, in lieu of erasing the memory altogether. In 2009, Dutch researchers at the University of Amsterdam tested the effect of beta-blockers (drugs normally used to treat heart conditions) on minimizing fear responses. They artificially created fearful memories in subjects by showing them unnerving pictures of spiders coupled with small electric shocks. A day later, half of the subjects were given beta blockers and again shown pictures of the spiders. The fear response that they had exhibited a day before was gone; the same was true on following days, suggesting the response had been permanently erased.


Eternal sunshine in pill form is closer than you may think. Researchers have already selectively erased memories in rats, and they have been able to dissociate memories from their negative emotions in humans. As for zapping memories like in Michel Gondry’s 2004 film, Liao tells Big Think this would be “pretty difficult” but that with FMRI brain scans, which pinpoint the parts of the brain that activate when someone thinks or remembers something, this might even be possible in the future.

Why We Should Reject This

Memory is a very complicated phenomenon, with many parts of the brain implicated in the storage of a single memory. “Memory is a network of neurons,” explained Liao, admitting that erasing one negative memory might unintentionally damage important positive ones. Plus, so much of our understanding of ourselves and the world is predicated on our memories; tampering with them could radically alter our inner narratives. 

Bad memories also serve purposes in themselves. In an article for Daily Mail, columnist Harry Phibbs argued that bad memories help us to learn from our mistakes: “Remembering our horrors and confronting them is the right moral course, not just to learn lessons ourselves but to warn others. … If we have a terrible burden on our conscience surely that is better as some restraint on our future conduct? Popping a pill and proceeding in a guilt-free manner with a hop, skip and a jump seems too easy.”

This technology introduces potential ramifications for criminal justice as well, John Harris, a bioethics professor from the University of Manchester, was quoted as saying in the Daily Mail: “Victims, say, of violence, might wish to erase the painful memory and with it their ability to give evidence against assailants. Similarly criminals and witnesses to crime may, under the guise of erasing a painful memory, render themselves unable to give evidence.”

More Resources
— Big Think special series “The Mystery of Memory