🔗 Share this article

"How much did Santa's sled cost? Zero, it was on the house."

This quip is met by groans that resonate through a storage facility in the capital.

This describes a humor-evaluation meeting with a company that makes supplies for social events. Its catalogue includes Christmas crackers.

The firm's founder grins, nearly sheepishly at the joke. But the joke has been selected and will feature in future crackers.

"The success is gauged by the gag by the number of moans and the loudness of the groans around the table," she says.

The key to a great Christmas cracker pun is not the identical as a good gag in itself. It is entirely about the setting - in this instance, the communal laughter of the holiday meal with grandparents, kids and potentially friends.

"You want the gag to be something that unites the eight-year-old in harmony with the 80-year-old," she adds.

The Neuroscience Behind Communal Laughter

Gathering to enjoy shared laughter is not only ancient, experts say, it is probably to be older than humanity.

"Therefore when you are laughing with people around the holiday table you are dropping into what's very likely a truly ancient mammalian social sound," explains a professor.

Shared laughter, she explains, helps make and maintain social bonds between people.

Researchers have discovered that a absence of such interactions can seriously damage mental and physical well-being.

"The people you talk to, and share laughter with, it leads to increased levels of endorphin release," the professor continues.

Endorphins are the brain's "happy chemicals" and are released both to reduce tension and discomfort and in response to pleasurable activities, such as chuckling with loved ones over a particularly awful festive cracker gag.

"You're not just chuckling at a foolish joke with a holiday cracker," the expert states. "You are in fact performing a lot of the truly vital task of making, maintaining the social bonds you have with those you love."

Which Happens Inside the Mind?

But what is truly taking place within the mind when we hear a gag?

An awful lot happens in response to humour, it transpires.

Using functional magnetic resonance imaging (fMRI), a type of neural imager which indicates which parts of the mind are working harder, researchers have been able to chart the areas that receive more blood.

Testing entails imaging the minds of healthy participants and then exposing them to a collection of funny words, paired with either a non-emotional sound, or recorded chuckles.

"During the study we observed a very interesting pattern of activation," says the neuroscientist.

A joke stimulates not just the parts of the mind responsible for hearing and understanding speech, but also brain areas involved in both planning and starting movement and those linked to vision and memory.

Put these elements together, and people listening to a joke have a complex set of neural reactions that underpin the laughter we hear.

The Infectious Nature of Laughter

Researchers discovered that when a funny phrase is paired with chuckles there is a greater response in the mind than the identical word when followed by a non-emotional sound.

"This was in areas of the mind that you would employ to move your face into a smile or a chuckle," she explains.

It means we are not just reacting to humorous jokes, they are responding to the amusement that accompanies them.

Amusement, according to the professor, can be infectious.

So what does this imply for the chuckles heard around a Christmas gathering?

"You laugh more when you know others," she notes, "and you laugh further when you are fond of them or love them."

When it comes to festive cracker jokes, she says, the feel-good effect is more probable to be triggered not by the joke in itself, but from the reaction to it.

"It's the laughter. The gag is the terrible Christmas cracker joke, and it's just a reason to laugh as a group."

The Quest for the Perfect Cracker Joke

Will we ever find the ultimate joke?

Probably not, but that has not stopped researchers from trying to.

In 2001, a professor set up a scientific search for the world's funniest gag.

More than 40,000 gags later, with scores provided by 350,000 people around the world, he has a clearer idea than many as to what succeeds and what fails.

The perfect Christmas cracker pun needs to be short, he says.

"But they also need to be bad jokes, jokes that make us groan," he adds.

The more "awful" the gag, he states the better.

"This is because if nobody laughs – it's the gag's shortcoming, not yours.

"The fascinating part about the holiday cracker puns is that not one person find them humorous.

"It creates a common moment around the table and I believe it's wonderful."