How do our brains decide what to do with our memories? Does new information become our main focus or is it stored for later use? University of Wisconsin-Madison researchers discovered that certain stored memories could be brought to mind with the help of magnets. The research sheds light on how the brain determines what memories to retrieve, knowledge that someday could help sufferers of mental illnesses who lack control over their thoughts.

In the study published in the journal Science, psychology professor Brad Postle and his lab challenged the idea that our working memory always keeps all of our memories on hand. They caught study participants' brains tucking away information that was deemed less important, and then researchers were able to bring the information back to mind with a magnetic pulse, according to a press release.

The lab conducted several experiments where they asked participants to remember two of three different types of information, including words, faces, and directions of motion.

Participants were either given a single cue for the type of upcoming question or two cues, with the second cue being the testers letting the participant know they would be asked about the question. This caused brain activity to rise, showing it was the focus of their attention.

Later, the participants were able to remember information presented to them without any cues thanks to a technique used by the researchers called transcranial magnetic stimulation (TMS). This involves applying an electromagnetic field to a particular section of the brain which helps store the word given to them, triggering the brain activity that can be seen in the participant’s focused attention. When remembering faces, researchers could help participants remember with a well-timed pulse from the TMS.

“We think that memory is there, but not active,” Postle said in a press release. “More than just showing us it’s there, the TMS can actually make that memory temporarily active again.”

Postle notes the majority of people believe they can focus on far more than they actually can at a given time, similar to how we can focus on an object in our vision but not everything in it.

"The notion that you're aware of everything all the time is a sort of illusion your consciousness creates," Postle said in a press release. "That is true for thinking, too. You have the impression that you're thinking of a lot of things at once, holding them all in your mind. But lots of research shows us you're probably only actually attending to — are conscious of in any given moment — just a very small number of things."

Studying how the brain recalls memories may help us understand and treat mental health disorders such as depression and schizophrenia. These disorders deal with focusing on either negative thoughts or hallucinations, according to a press release.

Read More: Peppermint Tea May Improve Memory, Cognitive Function — Chamomile Tea, Not So Much