Memory can be a heavy weight to bear.
Whether it's a childhood trauma or an experience that changed your life perspective for the worst, the past can be a terrible burden.
But leaving that luggage behind, rather than dragging it through life and letting it distort fresh experiences, is no easy feat.
In fact, in many ways, our mind works against us.
According to research published this week in the Journal of Neuroscience, the brain has a much harder time forgetting experiences than it does remembering them.
And that's a problem for people so scarred by the past that they can't move forward.
"We may want to discard memories that trigger maladaptive responses, such as traumatic memories, so that we can respond to new experiences in more adaptive ways," Jarrod Lewis-Peacock, the study's senior author and a researcher at University of Texas, explains in a press release.
The trouble is we may be going about the forgetting process all wrong. Most of us try to shed a bad memory by not thinking about it. Maybe time — and the brain's natural knack for blurring the sharp edges of the past — will allow that memory to slip into the folds of forgetfulness.
But the researchers found forgetting to be a surprisingly brain-intensive exercise. To forget something, you may actually have to think about it — not pretend it isn't there.
Up until now, methods for helping people get through past trauma have focused on just the opposite: pay less attention to the memories or through therapy or drugs, block the brain entirely from accessing them.
"Decades of research has shown that we have the ability to voluntarily forget something, but how our brains do that is still being questioned," Lewis-Peacock explains. "Once we can figure out how memories are weakened and devise ways to control this, we can design treatment to help people rid themselves of unwanted memories."
For their study, researchers used neuroimaging to track patterns of brain activity in a group of healthy adults. The participants were shown pictures of faces and scenes and asked to remember or forget each one.
They noted that the act of remembering was accompanied by moderate brain activity. But forgetting resulted in increased brain activity. It was simply a greater effort for the brain to lose information than it was to add it.
"A moderate level of brain activity is critical to this forgetting mechanism. Too strong, and it will strengthen the memory; too weak, and you won't modify it," study author Tracy Wang notes in the release. "Importantly, it's the intention to forget that increases the activation of the memory, and when this activation hits the 'moderate level' sweet spot, that's when it leads to later forgetting of that experience."
The bottom line? We can control what we forget. But to do so, we actually have to focus on it.
Maybe that's because the brain is such a meticulous librarian constantly obsessing over the information in its archives. And memories aren't just pasted in place like pages of a scrapbook. They're fluid, the researchers note, always being re-organized and revised by that busy brain.
But the mind may be loath to give up its memories — even the most painful ones — for good reason.
They serve an important purpose, too. Like stamps in a passport, they tell us where we've been — and remind us of places we really don't want to visit again.
Besides, while the brain does its own memory editing — softening our recall of bad experiences over time — most of us want to live an authentic life.
In a 2011 study, psychologists asked people if they would sign up for a drug that makes traumatic memories disappear. An overwhelming 82 percent of respondents said no thanks.
As Robert Nash, a psychology professor at Aston University writes in The Conversation:
"There is no doubt that we place a huge value on the (apparent) authenticity of our personal memories, both good and bad, and so it's clear that the idea of actively interfering with these memories seems wholly unappealing to many of us."
But what about those memories that leave scars so deep, they extend into our present? Are they candidates for an "Eternal Sunshine" scrubbing?
Memory can be a terrible thing. But the brain is careful not to throw out the proverbial baby with the bath water — and, when in doubt, may err on the side of keeping it all.
Which is why studies like this one may pave the way for therapy that helps us make conscious decisions about what past experiences are hurting us the most, and unburden ourselves from them accordingly.
"This will make way for future studies on how we process, and hopefully get rid of, those really strong, sticky emotional memories," Lewis-Peacock adds. "Which can have a powerful impact on our health and well-being."