It usually begins quietly. A thought appears without warning, tied to something unpleasant, and the body reacts before the mind can catch up. For people dealing with trauma or anxiety, this pattern can repeat for years. Scientists have long wondered whether memories like these can be softened without disturbing everything else stored in the brain. A new study suggests a possible route. Instead of forcing bad memories away, researchers explored what happens when positive memories are strengthened in their place. The work was small and careful, involving volunteers, sleep, and simple word games. Yet the results point to something unexpected. Negative memories may lose their hold when they are gently crowded out by better ones, especially during sleep.
Positive memories during sleep may help weaken bad ones
The study published on PNAS involved 37 participants and unfolded over several days. First, volunteers were asked to link made up words with unpleasant images. These images came from established databases and included scenes such as injuries or threatening animals. The aim was to create mild but clear negative associations.After a night of sleep, which helps the brain stabilise new memories, the researchers returned. This time, half of the same nonsense words were paired with positive images instead. Calm landscapes, smiling faces, ordinary scenes that felt safe. The idea was not to erase the original memory outright but to interfere with it by building a new emotional link.The researchers found that this interference mattered. People later struggled more to recall the original negative images linked to those words.
What role does sleep play in memory change
Sleep was central to the experiment. During the second night, the nonsense words were quietly played aloud while participants were in a deep phase of non rapid eye movement sleep. This stage is known to be important for memory processing.As the words were replayed, brain activity was measured using electroencephalography. The researchers noticed increased theta band activity, a signal often linked with emotional memory. This activity was stronger when the words had been reconnected with positive images rather than negative ones.In simple terms, the sleeping brain seemed more responsive to the positive associations. It replayed them more actively. By morning, this appeared to have shifted how those memories were stored and recalled.
What changed when people tried to remember
In the days that followed, participants completed questionnaires and memory tests. The differences were subtle but consistent. Words that had been paired again with positive images were less likely to trigger recall of the original negative scenes.Instead, positive memories intruded more often. When thoughts appeared involuntarily, they tended to carry a better emotional tone. Participants also rated these memories as less distressing than before.The researchers described this as a weakening of aversive recollection rather than deletion. The memory was still there, but it no longer dominated. This distinction matters. Forgetting entirely could remove useful learning. Changing emotional weight may be safer.
Could this help treat trauma and anxiety
The researchers were careful not to overstate their findings. Viewing negative images in a lab is not the same as living through trauma. Real world experiences are deeper, messier, and more personal. Overwriting those memories may be harder.Still, the study offers insight into how memory works. We already know the brain replays memories during sleep. This research suggests that replay can be nudged. Positive memories can be encouraged to take up more space, leaving less room for harmful ones.Such an approach is non invasive. It does not rely on medication or direct brain stimulation. That makes it appealing, though much work remains before it could be tested clinically.
Why this approach feels different
Many attempts to manage traumatic memory focus on suppression or avoidance. This method moves in the opposite direction. It works by addition rather than removal. For now, the findings suggest something modest but important. Memories are not fixed objects. They shift, overlap, and compete. Sometimes, the most effective way to quiet a bad memory is not to fight it, but to give the brain something else to hold onto.
