Perchance to dream

By • Published: August 24th, 2011
Category: Health in a Heartbeat

A certain song or word might remind you of something you’d much rather forget. And when you’re in a bad mood, sleeping away those unwanted memories might sound like a great idea.

Not necessarily, according to a new study in the Journal of Sleep Research. Sleep might actually hinder suppression of unwanted memories, making it easier for them to spring to mind.

You might remember being told not to stay awake studying until just before an exam, but to instead get a good night’s rest to help consolidate the new information you just learned. So what would sleep do for those memories you don’t want to come rushing back?

Research shows that working to actively suppress memories can make it harder to recall them later. This deliberate pushing away of memories involves acquiring new “forgetting” skills, so researchers wondered whether sleep might help consolidate those skills too.

To test this, participants in a European study learned pairs of words. Then, for half the list, they were given the first word of each pair and asked to recall the second word. For the other half of the list, participants had to do the opposite … deliberately try to keep the matching word out of the mind.

Some participants slept for eight hours after this exercise, and others stayed awake. In a later session they were all asked to recall partner words, including the ones they had worked so hard to forget.

Those who had slept generally recalled words more easily than did those who stayed awake. But sleep didn’t seem to make a difference when it came to forgetting unwanted words. In fact, the stage of sleep associated with dreams, called REM sleep, even appeared to make it easier to recall some of the suppressed memories. So sleep away. It will give you needed rest, though it might not help you forget.