🔗 Share this article

"What was the price did Father Christmas's sleigh cost? Zero, it was on the house."

This one-liner is greeted with moans that resonate through a storage facility in London.

We're at a joke-testing meeting with a firm that makes supplies for social events. Its catalogue features Christmas crackers.

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

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

The secret to a great Christmas cracker joke is not the same as a good joke per se. It is all about the setting - in this case, the shared laughter of the holiday dinner table with grandparents, children and possibly neighbours.

"You want the joke to be a thing that unites the eight-year-old in harmony with the 80-year-old," she states.

The Science Of Shared Laughter

Gathering to enjoy shared amusement is not only nothing new, experts say, it is probably to be older than humanity.

"So when you are laughing with people around the holiday dinner you are engaging in what's very likely a really ancient mammalian social sound," explains a neuroscience expert.

Communal laughter, she explains, helps make and maintain social connections between people.

Researchers have discovered that a absence of such interactions can seriously damage both psychological and bodily health.

"Those you talk to, and laugh with, it results in enhanced levels of endorphin uptake," she adds.

Endorphins are the brain's "happy chemicals" and are produced both to alleviate stress and pain and in reaction to enjoyable activities, such as laughing with friends over a truly awful festive cracker gag.

"You're not just chuckling at a silly pun with a holiday cracker," she states. "You are in fact performing a lot of the truly vital work of making, maintaining the connections you have with those you love."

Which Happens In the Brain?

But what is actually taking place inside the brain when we listen to a joke?

An awful lot happens in response to humour, it turns out.

Using functional magnetic resonance imaging (fMRI), a type of brain scanner which shows which parts of the brain are working harder, scientists have been able to map the regions that receive more blood.

The research entails scanning the minds of volunteer subjects and then exposing them to a collection of humorous phrases, paired with either a neutral sound, or recorded laughter.

"During the study we observed a very fascinating activation pattern of neural activity," says the neuroscientist.

A gag stimulates not just the parts of the mind in charge of hearing and interpreting speech, but also neural areas associated with both preparation and initiating motion and those involved in sight and memory.

Combine all of this as a whole, and individuals listening to a joke have a sophisticated set of brain reactions that underpin the amusement we hear.

The Contagious Power of Laughter

Researchers found that when a humorous word is combined with chuckles there is a greater response in the mind than the same phrase when followed by a non-emotional sound.

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

It means we are not just responding to funny words, they are reacting to the laughter that accompanies them.

Laughter, according to the expert, can be infectious.

So what does this mean for the laughter heard at a Christmas table?

"You laugh harder when you are familiar with people," she notes, "and you laugh further when you like them or care for them."

When it comes to Christmas cracker puns, she says, the positive factor is more likely to be caused not by the gag itself, but from the response to it.

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

The Quest for the Ideal Cracker Joke

Is it possible to discover the ultimate joke?

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

In 2001, a professor set up a research project for the world's most humorous gag.

Over tens of thousands of gags later, with ratings provided by hundreds of thousands of participants around the world, he has a better idea than many as to what succeeds and what fails.

The perfect festive cracker joke needs to be short, he says.

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

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

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

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

"It creates a shared moment around the gathering and I believe it's lovely."