🔗 Share this article

"What was the price did Father Christmas's sled cost? Nothing, it was on the house."

This quip is met by groans that echo through a warehouse in London.

We're at a joke-testing meeting with a company that produces products for social events. Its catalogue includes Christmas crackers.

The company's owner smiles, nearly apologetically at the joke. But the joke has made the cut and will appear in future crackers.

"You measure the joke by the volume of moans and the intensity of the groans around the table," the founder explains.

The secret to a great Christmas cracker pun is not the identical as a good joke per se. It is all about the setting - in this instance, the shared laughter of the holiday dinner table with elders, children and potentially friends.

"The goal is for the joke to be something that unites the child in harmony with the grandparent," she adds.

The Neuroscience Behind Shared Amusement

Coming together to experience communal laughter is not only ancient, scientists say, it is probably to be pre-human.

"Therefore when you are laughing with others around the holiday dinner you are engaging in what's very likely a really primordial mammalian play sound," says a neuroscience expert.

Communal amusement, she explains, aids in forge and strengthen social connections between people.

Scientists have found that a lack of such social exchanges can significantly harm both psychological and bodily well-being.

"The people you talk to, and laugh with, it leads to enhanced levels of 'happy chemical' release," she continues.

Endorphins are the body's "happy chemicals" and are released both to alleviate stress and pain and in reaction to enjoyable activities, such as chuckling with loved ones over a truly terrible festive cracker joke.

"You're not just laughing at a foolish pun with a Christmas cracker," she says. "You are in fact performing a lot of the really vital work of building, preserving the social bonds you have with the people you love."

Which Occurs In the Mind?

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

A tremendous amount happens in response to humour, it turns out.

Using functional magnetic resonance imaging (fMRI), a type of neural imager which shows which parts of the mind are more active, scientists have been able to chart the regions that receive more blood flow.

The research involves scanning the minds of healthy participants and then exposing them to a database of funny phrases, paired with either a neutral sound, or pre-recorded chuckles.

"During the study we got a very interesting activation pattern of activation," notes the professor.

A joke activates not just the parts of the mind in charge of hearing and interpreting language, but also brain regions involved in both planning and initiating movement and those linked to sight and memory.

Put these elements together, and people hearing a joke have a complex series of brain reactions that support the laughter we hear.

The Contagious Nature of Laughter

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

"This activation occurred in parts of the mind that you would use to contort your expression into a grin or a laugh," she says.

It means people are not just responding to humorous words, they are responding to the laughter that accompanies them.

Laughter, according to the expert, can be infectious.

So what does this imply for the chuckles heard around a holiday table?

"People laugh harder when you are familiar with others," she says, "and you laugh further when you are fond of them or care for them."

When it comes to Christmas cracker puns, she says, the positive effect is more probable to be caused not by the gag itself, but from the reaction to it.

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

The Quest for the Perfect Cracker Joke

Will we ever find the perfect joke?

Likely not, but that has not stopped experts from trying to.

In 2001, a psychologist established a scientific search for the planet's funniest joke.

More than tens of thousands of gags submitted, with scores lodged by 350,000 participants globally, he has a clearer idea than many 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 cause us to moan," he continues.

The increasingly "terrible" the gag, he says the better.

"The reason is that if no-one finds it funny – it's the joke's fault, not yours.

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

"That's a shared moment at the table and I think it's wonderful."