Researchers led by Brice Kuhl at Stanford University in California, US, conducted a study on the brain and found that the brain only chooses to remember memories that it deems important.
This is done by suppressing the memories that the brains thinks are less relevant, thus lessening its cognitive load, and preventing confusion.
"Whenever you're engaging in remembering, the brain adapts. It's constantly re-weighting memories," the New Scientist quoted Kuhl, as stating.
"In this simple test, we see it reverse memory to weaken competing memories. This is something that probably happens a lot in the real world," he added.
As a part of the study, that appears in Nature magazine, the researchers used functional magnetic resonance imaging (fMRI) to measure the brain activity of 20 healthy adults as they performed a simple memory test.
The test included memorising three pairs of words, two of which were closely associated. These pairs were: ATTIC dust, ATTIC junk and MOVIE reel.
After studying "ATTIC dust" twice, the participants were asked to recall all three pairs using the first words as cues.
The researchers found that on an average, people were better at recalling the unrelated pair 'MOVIE junk', than 'ATTIC junk'.
When the researchers compared the findings to the fMRI data taken during the test, they found that the brains of the participants was highly active in a region known for handling competing memories, which is also an area believed to induce memory suppression.
They now believe that the first region in the brain identified "ATTIC dust" and "ATTIC junk" as conflicting memories, leading to the second region to suppress "ATTIC junk" as it had only been seen once.
When the researchers asked the participants to undergo the test a second and third time, they noted that the suppression activity lessened in the brain, indicating the memory adjustment had been made.
The study is published in the journal Nature Neuroscience.