🔗 Share this article

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

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

This describes a joke-testing session with a company that makes products for gatherings. Its catalogue features festive crackers.

The company's founder grins, almost sheepishly at the joke. But the joke has been selected and will appear in upcoming crackers.

"The success is gauged by the gag by the number of moans and the intensity of the groans at the table," she says.

The key to a good Christmas cracker joke is not the same as a stand-up joke per se. It is entirely about the setting - in this case, the shared laughter of the Christmas meal with elders, children and potentially neighbours.

"You want the gag to be a thing that brings the child in harmony with the 80-year-old," she adds.

The Science Behind Communal Laughter

Coming together to enjoy shared amusement is not only ancient, scientists argue, it is probably to be pre-human.

"Therefore when you are laughing with people around the Christmas dinner you are engaging in what's very likely a truly ancient mammalian social sound," says a professor.

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

Researchers have discovered that a lack of such interactions can significantly harm mental and physical health.

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

Endorphins are the body's "feel-good compounds" and are produced both to alleviate stress and pain and in response to enjoyable experiences, such as laughing with friends over a truly terrible festive cracker joke.

"It's not simply laughing at a foolish pun with a Christmas cracker," she states. "You are actually performing a lot of the really vital work of building, preserving the social bonds you have with the people you care about."

Which Occurs Inside the Mind?

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

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

Employing brain scanning technology, a type of neural imager which indicates which areas of the mind are working harder, scientists have been able to map the areas that get more blood.

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

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

A joke activates not just the parts of the mind responsible for hearing and interpreting language, but also brain regions involved in 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 support the amusement we experience.

The Contagious Power of Laughter

Researchers found that when a funny word is paired with chuckles there is a greater response in the brain than the identical phrase when followed by a non-emotional sound.

"This was in parts of the brain that you would employ to move your expression into a grin or a chuckle," the professor explains.

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

Amusement, says the professor, can be contagious.

So what does this mean for the laughter found at a Christmas gathering?

"You laugh harder when you are familiar with others," she says, "and you laugh further when you are fond of them or care for them."

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

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

The Search for the Perfect Festive Pun

Will we ever discover the perfect joke?

Probably not, but that has not stopped experts from trying to.

Years ago, a psychologist established a research project for the planet's most humorous joke.

Over 40,000 jokes later, with ratings provided by hundreds of thousands of participants around the world, he has a clearer idea than many as to what works and what does not.

The ideal Christmas cracker pun needs to be brief, he says.

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

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

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

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

"It creates a shared experience at the table and I think it's wonderful."