It could be possible to learn new skills while you sleep, according to American scientists.
Researchers at Yale University investigated the brain function of lucid dreamers - people who have 'waking dreams' that they can manipulate - and found that they can control parts of their brain to open up and 'learn' while they sleep.
The study, published in New Scientist, found that these dreamers performed better in gambling tasks that stretch the regions in the brain that control social interaction and emotional decision-making.
The researchers are looking at how to train people with new skills by manipulating their dreams and implanting new ideas. They hope this could be used to improve a person's social control and decision-making abilities.
"We know that by engaging circuits in the brain we can change its architecture," says researcher Dr Peter Morgan from the study.
These findings, published in the New Scientist, follow a previous study where researchers from the University of Bern discovered that lucid dreamers who practiced throwing a coin into a cup were better at this skill in real life when they woke up.
If you have unusual dreams that you can't shake off the next morning, take a look at our dream decoder.
In another less-scientific sleep study this week, it has been found that what side of the bed you sleep on reveals a lot about our personality. The research, commissioned by Premier Inn claims that people who sleep on the left side of the bed are happier than those who snooze on the right. A quarter of 'lefties' woke up feeling positive, cheerful and ready to tackle the day as well as being better at dealing with stress, in comparison to grumpy right-hand sleepers.
Your sleep position is also said to be a telling sign, according to sleep expert, Professor Chris Idzikowskia, from the Sleep Assessment and Advisory Service. See his analysis of what your sleep position says about you.
"Those who curl up in the foetus position are described as tough on the outside but sensitive at heart. They may be shy when they first meet somebody, but soon relax. The foetus is the most common sleeping position, with women more likely to adopt this position than men."
"Lying on your back with both arms up around the pillow. These sleepers make good friends because they are always ready to listen to others, and offer help when needed. They generally don't like to be the centre of attention."
"Lying on your front with your hands around the pillow, and your head turned to one side. Often gregarious and brash people, but can be nervy and thin-skinned underneath, and don't like criticism, or extreme situations."
"Lying on your back with both arms pinned to your sides. People who sleep in this position are generally quiet and reserved. They don't like a fuss, but set themselves and others high standards."
"People who sleep on their side with both arms out in front are said to have an open nature, but can be suspicious, cynical. They are slow to make up their minds, but once they have taken a decision, they are unlikely ever to change it."
"Lying on your side with both arms down by your side. These sleepers are easy going, social people who like being part of the in-crowd, and who are trusting of strangers. However, they may be gullible."