🔗 Share this article

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

This joke is greeted with moans that resonate through a warehouse in the capital.

This describes a joke-testing meeting with a company that makes supplies for gatherings. Its catalogue includes festive crackers.

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

"The success is gauged by the joke by the number of moans and the intensity of the groans at the table," the founder explains.

The key to a great Christmas cracker pun is not the same as a good gag per se. It is entirely about the setting - in this instance, the communal laughter of the Christmas dinner table with elders, children and possibly friends.

"You want the gag to be something that brings the child in harmony with the grandparent," she adds.

The Neuroscience Of Shared Laughter

Coming together to enjoy shared amusement is not only nothing new, scientists argue, it is likely to be pre-human.

"So when you are chuckling with others at the holiday dinner you are dropping into what's almost certainly a really ancient mammal social vocalisation," explains a neuroscience expert.

Shared laughter, she explains, aids in forge and strengthen social connections between individuals.

Researchers have discovered that a absence of these interactions can seriously harm both psychological and bodily well-being.

"Those you talk to, and laugh with, it results in enhanced levels of endorphin uptake," the professor continues.

Endorphins are the body's "happy chemicals" and are produced both to reduce stress and pain and in reaction to enjoyable activities, such as chuckling with friends over a particularly terrible festive cracker joke.

"It's not simply chuckling at a foolish joke with a Christmas cracker," she says. "You are actually doing a lot of the really vital work of making, maintaining the connections you have with the people you care about."

Which Occurs In the Mind?

But what is truly taking place inside the brain when we hear a gag?

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

Using functional magnetic resonance imaging (fMRI), a type of neural imager which shows which areas of the brain are working harder, researchers have been able to map the regions that get more blood.

Testing involves imaging the brains of volunteer participants and then subjecting them to a database of humorous words, paired with either a neutral sound, or pre-recorded laughter.

"In the scanner we got a really interesting pattern of neural activity," says the professor.

A gag activates not just the parts of the mind in charge of auditory processing and understanding speech, but also brain regions involved in both planning and initiating movement and those linked to sight and recall.

Put these elements as a whole, and people listening to a joke have a complex series of neural reactions that underpin the amusement we hear.

The Contagious Nature of Laughter

Researchers discovered that when a funny word is combined with chuckles there is a greater response in the mind than the same word when accompanied by a non-emotional sound.

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

It indicates we are not just reacting to funny jokes, they are responding to the laughter that follows them.

Amusement, says the expert, can be contagious.

So what does this mean for the chuckles heard at a holiday gathering?

"People laugh more when you know others," she notes, "and you laugh further when you like them or care for them."

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

"The laughter is key. The joke is the dreadful Christmas cracker pun, and it's just a reason to chuckle together."

The Search for the Ideal Cracker Joke

Is it possible to discover the perfect gag?

Likely not, but that has not prevented researchers from attempting to.

Years ago, a professor established a scientific search for the planet's funniest gag.

More than tens of thousands of jokes later, with ratings lodged by 350,000 participants globally, he has a clearer understanding than most as to what succeeds and what fails.

The ideal Christmas cracker pun needs to be brief, he explains.

"But they also be bad jokes, puns that make us moan," he adds.

The more "awful" the joke, he says the more effective.

"This is because if no-one laughs – it's the joke's shortcoming, not your own.

"The fascinating part about the holiday cracker jokes is that none of us considers them humorous.

"That's a shared moment around the table and I think it's lovely."