The search is on for the funniest joke in the world. A year from now, when thousands of contenders have given way to the single greatest side-splitter, scientists hope to have learned something fundamental about the difference between an hilarious joke and a groaner.

Laugh Lab, an online humour experiment, was launched on Wednesday at the British Association for the Advancement of Science's annual meeting in Glasgow. It will be the largest-ever look at the psychology of humour, say its creators.

Anyone can participate by going to the project's website, www.laughlab.co.uk, to contribute new jokes or rate the ones already in the lab's archives.

To start the ball rolling, several famous British scientists have submitted their favourite jokes to the site. These gems will face off against a batch of computer-generated gags this week; the winner will be announced on Friday.

"I thought going into this that the scientists would win hands down," says psychologist Richard Wiseman of the University of Hertfordshire, who devised Laugh Lab. "Now that I've seen their jokes, I think it's going to be a pretty close contest."

When the general public starts contributing, Wiseman's group hopes to garner as many as 1,000 jokes on the first day. People who visit the site to rate jokes also fill in a short questionnaire about their age, gender and nationality, as well as a brief cognition quiz.

"We'll be able to answer questions like: 'Are there jokes that women find funny but men don't?'," Wiseman says. "And we can see if there's a universal joke that is funny all across the world."

"This will be the first opportunity to study these questions in a naturalistic way, without any pre-existing hypotheses," he adds.

Six months from now, the scientists will ask a professional comedian to record some of the funniest jokes, and let visitors to the website rate the performances with different-length pauses between the opening and the punchline.

The crowning moment will come at the end of the year, when one lucky person will get to listen to the funniest joke in the world, told with the optimum timing, while scientists peer at a scan of their brain.