🔗 Share this article

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

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

This describes a joke-testing meeting with a firm that produces products for gatherings. Its catalogue includes festive crackers.

The company's owner grins, almost sheepishly at the gag. But the joke has made the cut and will appear in upcoming crackers.

"You measure the joke by the number of groans and the loudness of the groans at the table," the founder says.

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

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

The Science Behind Communal Laughter

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

"So when you are laughing with others at the Christmas dinner you are dropping into what's very likely a truly ancient mammalian play sound," explains a neuroscience expert.

Shared laughter, she says, helps make and maintain social connections between people.

Researchers have found that a lack of such social exchanges can seriously harm mental and physical health.

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

These natural chemicals are the brain's "feel-good compounds" and are released both to reduce tension and discomfort and in response to pleasurable activities, such as laughing with loved ones over a truly terrible Christmas cracker gag.

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

Which Occurs Inside the Brain?

But what is truly happening within the brain when we hear a joke?

A tremendous amount occurs in response to humour, it transpires.

Using functional magnetic resonance imaging (fMRI), a kind of brain scanner which indicates which areas of the brain are working harder, researchers have been able to chart the areas that get more blood flow.

Testing involves imaging the minds of volunteer subjects and then subjecting them to a database of humorous words, paired with either a neutral sound, or recorded chuckles.

"In the scanner we got a very fascinating pattern of neural activity," notes the neuroscientist.

A joke stimulates not just the areas of the brain responsible for hearing and interpreting speech, but also neural areas associated with both planning and starting motion and those linked to sight and recall.

Put all of this together, and individuals listening to a pun have a complex set of neural reactions that underpin the amusement we experience.

The Contagious Nature of Chuckles

Researchers found that when a funny phrase is combined with laughter there is a stronger reaction in the mind than the same phrase when followed by a neutral sound.

"This was in parts of the mind that you would employ to move your expression into a smile or a laugh," she says.

It indicates we are not just reacting to humorous words, they are reacting to the amusement that accompanies them.

Amusement, according to the professor, can be contagious.

So what does this mean for the chuckles found around a holiday table?

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

When it comes to Christmas cracker jokes, she says, the positive effect is more likely to be triggered not by the gag in itself, but from the response to it.

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

The Search for the Perfect Festive Pun

Will we ever discover the ultimate gag?

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

In 2001, a psychologist established a research project for the planet's most humorous gag.

More than tens of thousands of gags submitted, with ratings provided by 350,000 participants globally, he has a better idea than most as to what works and what fails.

The ideal festive cracker pun must be short, he says.

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

The increasingly "terrible" the gag, he says the more effective.

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

"What's interesting about the holiday cracker jokes is that none of us find them funny.

"It creates a shared moment at the table and I believe it's lovely."