🔗 Share this article

"How much did Santa's sleigh cost? Zero, it was on the house."

This joke is met by groans that resonate through a warehouse in the capital.

This describes a humor-evaluation session with a company that produces supplies for gatherings. Its repertoire features festive crackers.

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

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

The key to a great holiday cracker joke is not the same as a good gag per se. It is all about the context - in this instance, the communal amusement of the Christmas meal with elders, children and potentially neighbours.

"You want the joke to be something that unites the eight-year-old together with the 80-year-old," she adds.

The Science Behind Communal Laughter

Gathering to enjoy communal amusement is not only nothing new, scientists say, it is probably to be pre-human.

"So when you are chuckling with people around the holiday dinner you are dropping into what's almost certainly a truly primordial mammal social vocalisation," says a neuroscience expert.

Shared amusement, she explains, helps make and maintain social bonds between individuals.

Researchers have found that a lack of these interactions can significantly damage both psychological and bodily health.

"Those you converse with, and laugh with, it results in increased 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 response to pleasurable activities, such as chuckling with loved ones over a truly awful Christmas cracker joke.

"You're not just laughing at a silly joke with a Christmas cracker," she says. "You are actually doing a lot of the really vital work of making, maintaining the social bonds you have with those you care about."

Which Occurs Inside the Brain?

But what is truly happening inside the mind when we hear a joke?

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

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

Testing involves scanning the minds of healthy subjects and then exposing them to a database of humorous words, accompanied by either a non-emotional sound, or recorded laughter.

"In the scanner we got a very interesting pattern of activation," says the neuroscientist.

A joke stimulates not just the areas of the brain responsible for hearing and interpreting speech, but also neural regions associated with both preparation and starting movement and those involved in sight and recall.

Put these elements as a whole, and individuals listening to a joke have a complex set of brain responses that underpin the amusement we hear.

The Infectious Nature of Chuckles

Researchers found that when a humorous phrase is paired with laughter there is a stronger reaction in the mind than the same phrase when accompanied by a neutral sound.

"This activation occurred in parts of the brain that you would employ to contort your face into a grin or a chuckle," she explains.

It means people are not just responding to humorous jokes, they are reacting to the laughter that follows them.

Amusement, says the expert, can be contagious.

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

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

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

"It's the laughter. The gag is the dreadful holiday cracker pun, and it's just a pretext to chuckle together."

The Quest for the Ideal Cracker Joke

Is it possible to discover the ultimate gag?

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

In 2001, a professor set up a scientific search for the world's funniest joke.

Over 40,000 gags later, with scores lodged by hundreds of thousands of people around the world, he has a better understanding than most as to what succeeds and what fails.

The perfect festive cracker pun must be short, he explains.

"They must also need to be poor jokes, jokes that cause us to groan," he adds.

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

"This is because if no-one laughs – it's the gag's shortcoming, not yours.

"What's interesting about the Christmas cracker jokes is that not one person find them humorous.

"It creates a shared moment around the table and I think it's wonderful."