They say truth is stranger than fiction, but it looks like fiction might’ve gotten it right this time. If you’ve ever seen the 2000 movie Memento, you’ll remember the whole story was told backwards because the main character has lost his short-term memory. Well, according to a study published in Nature Communications, the human brain works backwards to retrieve memories. It’s almost like Pearce’s character is an unintentional metaphor for the way the brain works. Freaky.
Researchers at the University of Birmingham found that the brain basically works backwards to remember something, starting with the “gist” of the memory first, according to a news release, then works to retrieve the specific details.
"We know that our memories are not exact replicas of the things we originally experienced," Juan Linde Domingo, lead author of the study, said in the news release. "Memory is a reconstructive process, biased by personal knowledge and world views — sometimes we even remember events that never actually happened. But exactly how memories are reconstructed in the brain, step by step, is currently not well understood."
The researchers said in the news release that the way the brain remembers something is the opposite from how it processes information. So when you look at something, the researchers said, the brain processes specific visual details — like its patterns and colors — first, and then the brain processes its abstract meaning, like if it’s a dog, guitar, or a cup. But when you’re trying to remember something, the researchers said the brain starts at a much higher level, and then gets more specific.
But your brain isn’t a limitless vault that stores memories of every single experience you’ve ever had. Researchers at Columbia University found that the brain prioritizes important memories and filters out “neutral” or “inconsequential” events. "Our memory is not an accurate snapshot of our experiences. We can't remember everything," Daphna Shohamy, senior study author and principal investigator at Columbia's Mortimer B. Zuckerman Mind Brain Behavior Institute and a professor in the Department of Psychology, said in the news release. "One way the brain solves this problem is by automatically filtering our experiences, preserving memories of important information and allowing the rest fade away."
The researchers from Birmingham University said understanding how the brain retrieves information could also help law enforcement better assess how reliable eye witness accounts at crime scenes are. It’s actually a myth that eyewitness testimony is a reliable form of evidence, according to the Association for Psychological Science (APS). In fact, 71 percent of the 358 people exonerated through DNA evidence since 1989 had been convicted and sentenced to death through eyewitness testimony, says the APS. But the APS says the myth persists because of pop culture — like crime shows and literary figures like Sherlock Holmes — and because people believe traumatic events should be memorable.
But the way the brain processes traumatic memories is more complicated. Richard Alan Friedman, professor of clinical psychiatry at Weill-Cornell Medical School, told NBC News that’s why people who experience a traumatic event often can’t provide a full account of what happened. “Things that are dangerous or scary are perfectly encoded [processed into a memory],” Friedman told NBC News. “Things that are not emotional are not attended to.”
Through follow-up studies, the researchers hope to better understand how the brain processes traumatic memories, along with complex memories and memories as the brain ages. What’s clear is that the human brain continues to be an amazing mystery that offers more questions than answers.