They checked out six of the most popular positions people sleep in, and found each one is linked to a different kind of person.

The most popular position is called the foetus, and more than two thirds of the 1,000 people they asked slept in that way.

The experts described these people as tough on the outside but sensitive at heart, and added they may be shy when they first meet somebody, but soon relax.

The six sleep positions are:

• The Foetus: curled up in a ball - tough on the outside but also shy
• Log: on your side with arms straight down - easy going, like being in the in-crowd
• The yearner: on your side with arms out in front - slow to make up their minds, but determined
• Soldier: on your back with arms at sides - quiet and reserved, sets high standards
• Freefall: on your front with hands around the pillow - loud on the outside, but sensitive inside
• Starfish: on your back with arms up around the pillow - good friend, helpful, dislikes centre of attention

Sleep expert, Professor Chris Idzikowski, also found that how good your night's sleep is may also be linked to the position you nap in.