Declutter the mind: Brain scans reveal how to best get rid of unwanted thoughts

BOULDER, Colo. — Even sitting at home in quarantine, our minds can be full of a thousand different thoughts that compete for our attention. It’s easy to say “think about something else” or “clean your mind,” but is it really that simple to do? A new study finds certain tricks work better than others when it’s time to declutter our minds. Researchers from the University of Colorado Boulder and the University of Texas say brain scans reveal how long your mind holds on to a thought, even after you try to get rid of it.

“We found that if you really want a new idea to come into your mind, you need to deliberately force yourself to stop thinking about the old one,” says co-author Marie Banich of CU Boulder in a university release.

Researchers enlisted 60 volunteers to see how well they flush thoughts from their working memory. Jarrod Lewis-Peacock, a cognitive neuroscience researcher at UT-Austin, compares a person’s working memory to a “scratch pad” for the mind. This is where humans store temporary thoughts we need to carry out tasks right away. Unfortunately, this part of the mind can only hold on to three or four different thoughts at one time. Before starting a new task, you have to clean out some of the old ones first.

“Once we’re done using that information to answer an email or address some problem, we need to let it go so it doesn’t clog up our mental resources to do the next thing,” Lewis-Peacock explains.

Dwelling on a problem can lead to trouble

While it might seem like some thoughts require our complete attention for however long it takes, researchers say dwelling on something — especially if it’s negative — can affect how you view new thoughts in the future. Banich warns this can even lead to mental health disorders.

“In obsessive compulsive disorder it could be the thought of as, ‘If I don’t wash my hands again I will get sick.’ In anxiety, it might be, ‘This plane is going to crash,'” the professor of psychology and neuroscience says.

Which word is best to clear your thoughts?

To see if people can really purge a thought from their mind, the participants underwent a series of functional magnetic resonance imaging machine (fMRI) scans. Researchers showed each volunteer pictures of faces, fruit, and landscapes and then asked them to hold the thought of that particular item for four seconds. At the same time, the fMRI scans created unique “brain signatures” revealing what each person’s brain looked like while they focused on each picture.

Study authors then told the group either “replace” the thought, “clear” all their thoughts, or “suppress” the thought by focusing on the image and then deliberately trying to stop thinking of it. In each case, the group’s brain signatures connected to the image visibly faded, showing humans really can get rid of an unwanted thought.

“We were thrilled,” Banich says. “This is the first study to move beyond just asking someone, ‘Did you stop thinking about that?’ Rather, you can actually look at a person’s brain activity, see the pattern of the thought and then watch it fade as they remove it.”

It’s not what you say, it’s how you say it

While the results reveal each of the key words successfully trigger a person to flush their memories, they didn’t all achieve this at the same speed.

Researchers find that telling someone to “replace” or “clear” a thought makes an brain image disappear faster. While they may be speedier, the results find part of the image still remains in the background.

Although telling someone to suppress an image takes longer to clear the thought, researchers find the brain signature fades away more completely. This leaves the mind more open for new thoughts.

“The bottom line is: If you want to get something out of your mind quickly use ‘clear’ or ‘replace,’ but if you want to get something out of your mind so you can put in new information, ‘suppress’ works best,” Banich reports.

Out of sight and out of mind

The study authors conclude that for people stuck on a problem or having trouble multitasking, their findings suggest the best way to deal with it is to simply stop thinking about it for a while.

“People often think, ‘If I think about this harder I am going to solve this problem.’ But work by clinicians suggests it can actually give you tunnel vision and keep you in a loop that is hard to get out of,” the CU-Boulder researcher explains.

For mental health counselors, the study suggests that to help someone completely eliminate a troubling memory, the patient may need to intentionally focus on it and then push it aside. The team adds brain imaging could one day help health professionals monitor how well patients are ridding themselves of harmful thoughts.

“If we can get a sense of what their brain should look like if they are successfully suppressing a thought, then we can navigate them to a more effective strategy for doing that,” Lewis-Peacock concludes. “It’s an exciting next step.”

The study appears in the journal Nature Communications.

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