March 11 (UPI) -- Letting go of a piece of information may take more work than holding on to it, a new study says.
To forget a memorable experience, people must use more mental energy to redirect their attention from it than to just keep remembering it, according to findings published Monday in the Journal of Neuroscience.
"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, said in a press release.
"Decades of research has shown that we have the ability to voluntarily forget something, but how our brains do that is still being questioned. 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."
Memories aren't just fixed in place. Rather, they are revised and shifted around as time goes on, the researchers say.
Forgetting things, they say, forces the brain to use a moderate amount of brain activity compared to what it takes to keep memory intact.
"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," Tracy Wang, a researcher at University of Texas and study lead author, said in a news 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 researchers used neuroimaging to locate patterns of brain activity, after showing study participants images of pictures and faces. They asked them to either forget or remember each image.
The exercise showed researchers that it's easiest for people get rid of memories of faces.
"We're learning how these mechanisms in our brain respond to different types of information, and it will take a lot of further research and replication of this work before we understand how to harness our ability to forget," Lewis-Peacock said. "We're looking not at the source of attention in the brain, but the sight of it."