🔗 Share this article

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

This joke is greeted with moans that echo through a warehouse in London.

This describes a humor-evaluation meeting with a firm that produces products for social events. Its repertoire includes Christmas crackers.

The firm's owner smiles, almost sheepishly at the gag. But the pun has made the cut and will feature in future crackers.

"You measure the gag by the volume of moans and the loudness of the groans at the table," she explains.

The key to a good holiday cracker joke is not the same as a stand-up joke per se. It is all about the context - in this case, the shared amusement of the holiday meal with elders, children and potentially friends.

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

The Neuroscience Behind Communal Laughter

Gathering to experience communal amusement is not only nothing new, experts argue, it is likely to be pre-human.

"So when you are laughing with people around the Christmas table you are dropping into what's very likely a truly ancient mammalian social vocalisation," says a neuroscience expert.

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

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

"The people you talk to, and laugh with, it leads to enhanced amounts of 'happy chemical' uptake," she adds.

These natural chemicals are the brain's "feel-good compounds" and are released both to reduce stress and pain and in reaction to pleasurable activities, such as laughing with loved ones over a particularly terrible festive cracker gag.

"It's not simply laughing at a silly joke with a Christmas cracker," she says. "You are in fact performing a lot of the truly vital task of building, preserving the social bonds you have with those you care about."

Which Happens Inside the Brain?

But what is truly happening inside the brain when we listen to a joke?

A tremendous amount happens in reaction to humour, it transpires.

Using brain scanning technology, a kind of brain scanner which indicates which parts of the mind are more active, researchers have been able to chart the regions that get more blood flow.

Testing entails imaging the brains of volunteer subjects and then exposing them to a collection of humorous phrases, accompanied by either a non-emotional sound, or pre-recorded chuckles.

"During the study we got a very interesting activation pattern of neural activity," notes the neuroscientist.

A joke activates not just the parts of the mind responsible for auditory processing and interpreting language, but also brain regions involved in both planning and initiating movement and those involved in sight and memory.

Put all of this as a whole, and people hearing a pun have a sophisticated series of neural reactions that underpin the laughter we experience.

The Contagious Power of Laughter

Researchers found that when a funny phrase is combined with laughter there is a greater response in the brain than the same phrase when followed by a non-emotional sound.

"This was in areas of the brain that you would use to contort your expression into a smile or a laugh," she says.

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

Amusement, says the professor, can be infectious.

So what does this mean for the laughter found around a Christmas table?

"People laugh harder when you know people," she says, "and laughter increases more when you are fond of them or love them."

When it comes to festive cracker jokes, she says, the feel-good factor is more probable to be caused not by the joke itself, but from the response to it.

"It's the laughter. The gag is the dreadful Christmas cracker joke, and it's just a pretext to laugh together."

The Search for the Ideal Cracker Joke

Is it possible to discover the ultimate joke?

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

Years ago, a professor set up a scientific project for the world's funniest joke.

More than tens of thousands of gags submitted, with scores provided by hundreds of thousands of people globally, he has a clearer understanding than many as to what succeeds and what fails.

The ideal Christmas cracker joke must be brief, he explains.

"They must also need to be bad jokes, jokes that cause us to moan," he continues.

The increasingly "awful" the joke, he states the better.

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

"The fascinating part about the Christmas cracker jokes is that not one person find them funny.

"It creates a common experience around the table and I believe it's lovely."