Updated on: Wednesday, January 18, 2012
If you think sleeping on a problem is the best way to solve it, think again, for a new study has claimed that it could actually make matters worse.
This is because a team at the University of Massachusetts Amherst say that sleeping on a problem causes painful memories to remain more vivid, contradicting previous researches which claim that a nap can help one to come up with a solution.
The study found that unpleasant experiences stay more upsetting if people sleep immediately after the event than if they digest the memory while being awake, 'The Daily Telegraph' reported.
Team leader Rebecca Spencer said: "We found that if you see something disturbing, let's say an accident scene, and then you have a flashback or you're asked to look at a picture of the same scene later, your emotional response is greatly reduced, ie, you'll find the scene far less upsetting if you stayed awake after the original event than if you slept."
The findings make sense from an evolutionary perspective, because retaining vivid memories of negative events would have taught our ancestors to avoid repeating them in future, she was quoted by the British newspaper as saying.
They could also be significant for people suffering from post-traumatic stress disorder or eyewitnesses in court cases, say the researchers.
For their study, the team showed 106 young adults pictures, some of which were designed to be upsetting, and asked participants to rate their emotional response to them.
After a 12-hour gap the subjects were shown another set of pictures, some of which were the same, and asked to give fresh emotional feedback on each image and state whether or not they had seen it before.
Participants who slept overnight between viewings were better at recognising images they had seen and retained stronger negative feelings about them compared with those who saw the pictures in the morning and again the same evening.
Spencer said the new study provides the first evidence that sleep preserves not only our memory of emotional events but also our sensitivity to them.
She said: "Some previous studies have looked at just memory itself, not how emotional reactivity changes. There have been a few studies which look at one or the other but this is the first to look at them side by side."