Science Backs Up Old Saying, 'Never Go To Bed Angry'

Never go to bed angry or having a bad feeling about something is maybe one of the most common advices one may have received. Some think that it is just a normal relationship cliché, while some think that it is a good idea to live by these words. A study has revealed that sleep builds up bad memories, which will make one live with them longer than normal.

According to The Guardian, scientists have discovered evidence that can support the idea that negative emotional memories are harder to get rid of after a night's sleep. The study, published in the journal Nature Communications, claims that when one sleeps, the brain reorganizes the way negative memories are kept, which makes the association more difficult to forget in the future.

"In our opinion, yes, there is certain merit in this age-old advice," said Yunzhe Liu, who led the research at Beijing Normal University and is now based at University College London. "We would suggest to first resolve argument before going to bed; don't sleep on your anger."

For the study, Liu and a team of researchers enlisted 73 male college students to test how well they could intentionally keep negative memories, and determine how sleeping may influence the process. The participants were trained to link images of neutral faces with disturbing images of things like injured people, mutilated bodies and crying children.

The next day, after a full night's sleep, they were shown the neutral faces again and instructed to either recall the negative associations or to try to suppress them, using a psychological technique called think/no-think, reported Science Alert.

When this session was done just 30 minutes after the initial learning, the participants were 9 percent less likely to remember the images that they had avoided thinking about compared to control image pairs -- the suppression had been effective. However, when the suppression session was carried out 24 hours after the initial learning, after a good night's sleep, they were only 3 percent less likely to recall the image.

Brain scans determined why memories may be more difficult to forget once they have been consolidated by sleep. Functional MRI scans of the participants revealed how newly acquired memories were represented by brain activity tightly centered on the hippocampus, the brain's memory center, but the overnight memories had become more distributed across the cortex.

However, the authors warned that the findings were in healthy participants and are not immediately applicable to conditions like PTSD and expecting people who have suffered a traumatic experience to start working on suppressing the memory on the same day is "probably not realistic advice," Liu said. However, the research could help design evidence-based treatments for PTSD in the future, he said.

"We think the "reconsolidation" technique may be useful, so that we first evoke this piece of memory, and then try to suppress that," Liu said, referring to a treatment strategy in which old information is called to mind with the aim of modifying the memory either with drugs or through behavioral interventions.