And maybe even adding new ones.
Traumatic experiences, deaths, bad break-ups, embarrassing moments — all of us have experienced some things in our past that can be particularly hard to think about. These painful memories can trigger feelings of anxiety, fear, depression, or conditions like post-traumatic stress disorder.
Wouldn’t it be easier to just erase the painful memories, Eternal-Sunshine-of-the-Spotless-Mind style? Scientists have now figured out how to erase and change memories, and even implant new ones — not just in animals, but human subjects, according to the PBS documentary Memory Hackers. Additionally, scientists are working on drugs that could rewire our brains to forget the bad memories and triggers.
It turns out that memories, even long-term ones, aren’t as permanent as once believed. Scientists used to think that memories were stored in one specific spot in the brain, but thanks to advances in neurological scanning, they’ve discovered that each memory we have is secured in connections across the brain. Our memories form when proteins stimulate our brain cells to grow and form these new connections, to state it simply.
But what’s important to understand when it comes to memories, is that each time you recall a memory, you’re really remembering the last time you thought about it. Because of this, our memories are malleable, meaning they can be reset a bit differently and more vividly than before.
This process is called reconsolidation, and it explains why we don’t always remember the past in perfectly accurate detail. It’s during the reconsolidation process that scientists can “hack” our memories to change or erase them.
By blocking a chemical called norepinephrine, which is involved in the fight or flight response, researchers can effectively cloud up our recollection of traumatic memories — and this has been demonstrated in a number of studies already.
For instance, researchers from the Netherlands showed that, by using a drug called propranolol to block norepinephrine, they could take away the fear of spiders in arachnophobes. Two of three groups of arachnophobes were shown a tarantula in a glass jar to trigger their fear of spiders, and then were given either propranolol (the norepinephrine blocker) or a placebo. In order to rule out the possibility that the drug on its own could reduce fear, the researchers gave a third group propranolol but didn’t show them a spider.
Over the next few months, the researchers measured the participants’ fear responses when they were presented with another tarantula, and the results were impressive — the group that wasn’t exposed to a spider and the group that took a placebo both showed no change in their fear levels to spiders, but the arachnophobes who took the drug and faced the spider were able to actually touch the tarantula within days. Some of them grew comfortable enough to even hold the tarantula, and the fear didn’t come back, even after a year. Essentially, it was like it had been erased.
For obvious ethical reasons, researchers haven’t tried to totally delete an entire memory from humans, at least not so far. However, the evidence suggests that with the right drugs and reconsolidation exercises, it would be possible, and may even one day be used to help people struggling with anxiety, phobias, and PTSD.
What’s a bit unsettling about the whole idea is the potential of adding false memories into someone’s brain. Elizabeth Loftus, cognitive psychologist and expert on human memory, demonstrated that she could successfully plant false memories in one-fifth of the participants in her study. She convinced them that they had a memory of being lost in a mall as a child simply through a series of suggestions and implications — a golden example of just how malleable our memories are.
While getting lost in the mall is a more common childhood experience, other studies have convinced subjects that they almost drown, were attacked by a vicious animal, or witnessed a demonic possession during their childhood. Pretty crazy stuff.
"Rewriting memories allows you to update them, but the purpose of forgetting is not just so you can clean off the hard drive,” Michael Bicks, the creator of the Memory Hackers documentary, told Co.Create. “The ability to forget the unpleasant things allows us to create a story about ourselves that we can live with."