Has your mother ever told you not to go to bed angry?
If so, she might be right.
In fact, researchers have found that it’s harder to forget bad memories if you’re distressed or angry when you head to bed.
Never Go To Bed Angry
A study from the National Center of Neurology and Psychiatry in Tokyo examined two groups of 14 healthy volunteers after aversive (motor vehicle accident films) and nonaversive episodic memory stimuli. The sleep-deprived group had no sleep at all during day 1 and both groups were examined on Day 1,3, and 10.
In the sleep-deprived group, all participants no longer had any physiological and generalized fear responses when recalling the memory stimuli at the day 10 mark.
“The results are of major interest for treating the frequent clinical problem of unwanted memories, memories of traumatic events being the most prominent example,” says Christoph Nissen at the University of Freiburg Medical Center in Germany, who was not involved in the work (3).
Taking it Further
Another study examined 73 male students who were asked to memorize 26 mugshots, each paired with a disturbing image. These included crying children, lifeless bodies, and gruesome injuries.
On the second day, after a good night’s sleep, half of the participants were asked to recall the images associated with half of the mugshots. The other half were instructed to actively suppress the memories. Both groups were then pushed to memorize a fresh batch of mugshot and images.
30 minutes later, both groups went through the same recall/suppress process. Through the comparison, researchers found that the suppression technique worked best 30 minutes after seeing the images than after a 24-hour period.
Science Alert explains how it works: “When the participants tried to remember or inhibit the memories only 30 minutes after learning the associations, their neural activity was centered in the hippocampus – the part of the brain primarily associated with memory.” (4)
“But after a night’s sleep, the memory task showed that neural activity was reduced in the hippocampus, having dispersed among a number of cortical regions also associated with memory and information processing, including the lateral parietal cortex, angular gyrus, and middle temporal gyrus.”
Going through these different structures ingrains the memory in your brain.
So what does this mean for people suffering from a traumatic event or simply a negative experience?
“We suggest that people try to get a bad memory out of their minds as soon as they can, not to think about it too much, and especially not to sleep on it,” says Yunzhe Liu of University College London, who worked on the study at Beijing Normal University in China.