🔗 Share this article

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

This joke is met by groans that echo through a storage facility in London.

We're at a joke-testing session with a company that produces products for gatherings. Its repertoire includes festive crackers.

The firm's owner grins, almost sheepishly at the joke. But the joke has been selected and will feature in future crackers.

"The success is gauged by the joke by the volume of groans and the loudness of the groans at the table," the founder explains.

The secret to a great Christmas cracker joke is not the same as a good gag per se. It is all about the setting - in this case, the communal amusement of the holiday dinner table with grandparents, kids and potentially friends.

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

The Neuroscience Behind Shared Laughter

Coming together to experience shared amusement is not only ancient, experts say, it is probably to be pre-human.

"So when you are laughing with people around the Christmas dinner you are dropping into what's almost certainly a truly ancient mammal social sound," says a professor.

Shared amusement, she says, helps forge and strengthen social bonds between people.

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

"Those you talk to, and laugh with, it results in increased amounts of 'happy chemical' uptake," the professor continues.

Endorphins are the body's "feel-good compounds" and are released both to alleviate stress and pain and in response to pleasurable activities, such as laughing with loved ones over a truly terrible festive cracker joke.

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

Which Happens Inside the Brain?

But what is actually taking place within the mind when we listen to a joke?

A tremendous amount happens in response to comedy, it transpires.

Employing functional magnetic resonance imaging (fMRI), a kind of neural imager which shows which areas of the mind are more active, researchers have been able to map the regions that get more blood flow.

The research entails imaging the brains of volunteer subjects and then exposing them to a collection of funny phrases, paired with either a neutral sound, or recorded chuckles.

"In the scanner we observed a very interesting activation pattern of neural activity," notes the professor.

A gag activates not just the parts of the mind in charge of auditory processing and interpreting speech, but also brain regions associated with both planning and starting movement and those involved in vision and recall.

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

The Infectious Power of Laughter

Scientists found that when a humorous phrase is combined with laughter there is a greater response in the mind than the same word when followed by a neutral sound.

"This was in parts of the mind that you would employ to contort your face into a smile or a chuckle," she says.

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

Amusement, according to the professor, can be infectious.

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

"People laugh more when you are familiar with people," she notes, "and laughter increases more when you like them or care for them."

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

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

The Search for the Perfect Festive Pun

Will we ever discover the ultimate joke?

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

Years ago, a psychologist set up a research project for the world's most humorous joke.

More than tens of thousands of gags later, with ratings lodged by 350,000 people globally, he has a clearer idea than most as to what succeeds and what fails.

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

"They must also be poor jokes, puns that make us moan," he adds.

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

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

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

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