We tend to think of memories as perfect little time capsules—important records of past events that matter to us and made us who we are, as unchangeable as a dragonfly stuck in amber. Well, they're anything but. I recently met with Julia Shaw, a criminal psychologist who specializes in the science of memory. "I am a memory hacker," Shaw told me. "I use the science of memory to make you think you did things that never happened."
Implanting a false memory, it turns out, is alarmingly easy to do.
Shaw, a Canadian now living in London, was in Toronto to promote her new book, The Memory Illusion. In it, she describes how false memories can be deliberately placed in people's brains—leading to false police confessions that could send the wrong person to jail, or detailed accounts of alien abductions that (almost certainly) never happened.
"A memory is a network of brain cells," Shaw explained to me. That network, which stretches across different regions of the brain, is constantly being updated. It's an important function that allows us humans to learn new things and to problem-solve, among other skills. But as a result, it "can be manipulated," she continued. "Each time you tell a story, you change the memory," maybe dropping in new details, weaving in tidbits you really heard from somebody else, or forging new, and possibly inaccurate or misleading, connections.
For example: If you think you remember anything before you were about two-and-a-half years old, Shaw said, that's a false memory. (Before then, our brains aren't developed enough to store memories, a phenomenon called childhood or infantile amnesia.) A memory from earlier that "was either given to you through photos, you saw a picture, or maybe your parents told you a story," she explained. "You can internalize them quite readily."
"I think that reality is purely your perception"
The fact that memories are so changeable has important implications for, among other things, the criminal justice system, Shaw pointed out—and that's the focus of much of her work. "In the lab, I convince people through memory hacking that they committed crimes that never happened," said Shaw, senior lecturer and researcher in the Department of Law and Social Sciences at London South Bank University. "I do it to show that the interrogation process can really distort memories, in consistent ways."
To implant a false memory, "you try to get someone to confuse their imagination with their memory," she said. "That's it: Get them to repeatedly picture it happening."
She'll start off by letting them know they committed a crime, and then claim to have insider information. For example: "Your parents told me that, when you were 14, you stole something, and the police were involved," she said, adding that she'll say she called the parents, and give details of their talk, "and then you believe me. You know I contacted your parents, and you trust them," she continued. That gives her credibility.
She'll keep going and layer in detail—the person's age, hometown, the name of their childhood best friend, and get them to repeatedly imagine the crime happening, over and over again, even if they never did it. Over the course of a couple of weeks, maybe even a shorter timespan than that, "it gets harder to decipher imagination, versus a memory coming back," Shaw said. "By the end, it's easy to think, this actually happened."
Of course, false memories produce disastrous consequences within the criminal justice system, sending innocent people to jail. But they could also help explain so-called "impossible memories," Shaw said, like someone who's certain they were taken by aliens. Once mental illness or another explanation has been ruled out, "it's possible that some have false memories," she said. "They've pictured it repeatedly, or it's been suggested to them. Or they watched a movie, and dreamt about it," and then start believing it's true.
So when will we be able to do the opposite of implanting a false memory—deleting a real one, that's possibly painful and unwanted, from our minds?
"Eternal Sunshine of the Spotless Mind," Shaw nodded when I brought it up. Because memories are made up of networks across the brain, it doesn't seem likely we'll be able to pluck away an entire recollection anytime soon. What seems more likely, she said, is that we'll be able to remove the piece of it that matters most: the emotion that's tied up in it.
With optogenetics (a technique that uses light to switch various parts of the brain on and off), scientists are capable of erasing the fear associated with bad memories, in rats. This hasn't yet been done in humans, of course. (Optogenetic techniques currently require cutting a big old hole in the rats' skulls.) But it hints at what could be possible.
So, if our memories are so easy to manipulate, and constantly in flux, pulling in new details and dropping others, is anything we remember really a true record of the past?
"I think that reality is purely your perception. And it's a completely personal experience. The world as you know it only exists to you, [as you are] right now. Every day you wake up a new person," with a different brain, and a different set of memories to guide you.
"I like to say that all memories are essentially false," Shaw said. "They're either a little bit false, or entirely false. There are entire experiences that never happened."
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