🔗 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 London.

We're at a joke-testing meeting with a firm that makes products for gatherings. Its repertoire features Christmas crackers.

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

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

The key to a good holiday cracker joke is not the identical as a good joke in itself. It is all about the context - in this instance, the communal laughter of the holiday meal with elders, children and potentially neighbours.

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

The Neuroscience Of Shared Laughter

Coming together to enjoy shared laughter is not only nothing new, scientists argue, it is likely to be older than humanity.

"Therefore when you are chuckling with others at the Christmas dinner you are engaging in what's very likely a really ancient mammal social vocalisation," says a neuroscience expert.

Communal laughter, she says, helps forge and strengthen social connections between individuals.

Scientists have discovered that a lack of these social exchanges can significantly harm mental and physical well-being.

"Those you talk to, and share laughter with, it leads to enhanced levels of endorphin uptake," the professor adds.

Endorphins are the body's "feel-good compounds" and are produced both to reduce stress and pain and in response to pleasurable experiences, such as chuckling with friends over a particularly terrible festive cracker gag.

"You're not just laughing at a silly joke with a Christmas cracker," she states. "You are in fact performing a lot of the truly important work of building, preserving the connections you have with the people you care about."

What Happens In the Brain?

But what is truly taking place within the mind when we hear a joke?

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

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

The research involves scanning the brains of volunteer participants and then exposing them to a database of humorous words, paired with either a neutral sound, or recorded chuckles.

"During the study we got a very fascinating pattern of neural activity," notes the professor.

A joke activates not just the parts of the mind in charge of auditory processing and understanding language, but also neural areas involved in both preparation and initiating motion and those involved in sight and memory.

Combine these elements together, and individuals listening to a joke have a sophisticated set of brain reactions that underpin the laughter we hear.

The Contagious Nature of Laughter

Scientists discovered that when a humorous word is paired with laughter there is a stronger response in the mind than the same word when accompanied by a neutral sound.

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

It indicates we are not just reacting to funny jokes, they are responding to the amusement that follows them.

Laughter, says the professor, can be infectious.

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

"You laugh more when you are familiar with people," she says, "and you laugh more when you like them or care for them."

When it comes to festive cracker puns, she says, the positive factor is more likely to be triggered not by the gag itself, but from the reaction to it.

"The laughter is key. The gag is the terrible holiday cracker pun, and it's just a reason to chuckle as a group."

The Quest for the Ideal Festive Pun

Is it possible to find the ultimate joke?

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

In 2001, a psychologist established a scientific project for the world's most humorous gag.

More than 40,000 gags later, with ratings lodged by hundreds of thousands of participants around the world, he has a clearer idea than most as to what works and what fails.

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

"They must also be bad gags, jokes that cause us to groan," he adds.

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

"The reason is that if nobody finds it funny – it's the gag's fault, not your own.

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

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