How Do Festive Cracker Jokes Influence Our Brains?

"How much did Father Christmas's sled cost? Zero, it was on the house."

This one-liner is met by groans that resonate through a storage facility in London.

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

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

"You measure the gag by the number of moans and the intensity of the groans around the table," she explains.

The key to a great Christmas cracker joke is not the identical as a good gag in itself. It is all about the setting - in this case, the shared laughter of the holiday meal with elders, children and potentially friends.

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

The Neuroscience Behind Shared Laughter

Coming together to enjoy shared laughter is not only nothing new, scientists argue, it is likely to be pre-human.

"So when you are chuckling with people at the holiday dinner you are dropping into what's very likely a really primordial mammal social sound," explains a professor.

Communal amusement, she says, helps make and maintain social connections between people.

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

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

These natural chemicals are the brain's "feel-good compounds" and are released both to alleviate stress and pain and in reaction to enjoyable activities, such as chuckling with friends over a particularly awful festive cracker gag.

"It's not simply laughing at a foolish joke with a holiday cracker," the expert states. "You are actually performing a lot of the truly vital work of making, maintaining the connections you have with the people you love."

Which Occurs Inside the Brain?

But what is actually taking place inside the brain when we hear a gag?

A tremendous amount happens in reaction to humour, it turns out.

Employing functional magnetic resonance imaging (fMRI), a kind 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 involves scanning the minds of volunteer subjects and then subjecting them to a database of funny words, paired with either a neutral sound, or pre-recorded laughter.

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

A joke activates not just the areas of the brain responsible for auditory processing and interpreting language, but also brain areas involved in both planning and starting motion and those involved in vision and memory.

Put all of this as a whole, and people listening to a pun have a sophisticated set of neural responses that underpin the amusement we experience.

The Contagious Power of Laughter

Scientists discovered that when a humorous phrase is combined with laughter there is a stronger reaction in the brain than the same phrase when followed by a neutral sound.

"This activation occurred in parts of the mind that you would employ to contort your face into a grin or a laugh," she says.

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

Amusement, according to the professor, can be contagious.

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

"You laugh more when you know people," she says, "and laughter increases further when you like them or love them."

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

"The laughter is key. The joke is the terrible Christmas cracker joke, and it's just a pretext to laugh as a group."

The Quest for the Perfect Cracker Joke

Is it possible to find the perfect joke?

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

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

Over 40,000 jokes later, with ratings lodged by hundreds of thousands of people globally, he has a better understanding than most as to what works and what does not.

The ideal Christmas cracker joke needs to be short, he says.

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

The increasingly "awful" the gag, he says the better.

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

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

"That's a shared moment around the table and I think it's lovely."