🔗 Share this article

"How much did Santa's sled cost? Nothing, it was on the house."

This joke is greeted with groans that resonate through a warehouse in the capital.

We're at a humor-evaluation session with a company that makes products for gatherings. Its repertoire features Christmas crackers.

The firm's founder smiles, nearly sheepishly at the gag. But the pun has made the cut and will appear in upcoming crackers.

"You measure the joke by the number of groans and the intensity of the groans at the table," she explains.

The key to a good Christmas cracker pun is not the same as a good gag per se. It is entirely about the context - in this instance, the shared amusement of the holiday meal with grandparents, kids and potentially neighbours.

"You want the gag to be a thing that unites the eight-year-old in harmony with the 80-year-old," she states.

The Neuroscience Behind Communal Laughter

Gathering to enjoy shared laughter is not only ancient, experts argue, it is likely to be pre-human.

"So when you are laughing with people around the holiday table you are engaging in what's almost certainly a really ancient mammal social sound," says a professor.

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

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

"Those you converse with, and laugh with, it leads to enhanced levels of 'happy chemical' release," the professor continues.

Endorphins are the body's "feel-good compounds" and are released both to reduce tension and discomfort and in reaction to enjoyable experiences, such as laughing with friends over a truly awful Christmas cracker gag.

"You're not just laughing at a silly pun with a Christmas cracker," the expert states. "You are actually doing a lot of the really important work of building, preserving the social bonds you have with the people you care about."

Which Happens Inside the Brain?

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

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

Using functional magnetic resonance imaging (fMRI), a kind of brain scanner which shows which areas of the brain are working harder, scientists have been able to map the areas that get more blood.

The research involves imaging the brains of healthy participants and then exposing them to a database of humorous phrases, accompanied by either a non-emotional sound, or pre-recorded laughter.

"During the study we got a really interesting pattern of neural activity," says the professor.

A joke stimulates not just the parts of the brain responsible for auditory processing and interpreting speech, but also brain regions involved in both planning and initiating movement and those involved in sight and recall.

Put all of this as a whole, and individuals listening to a joke have a sophisticated series of brain responses that support the laughter we hear.

The Infectious Power of Laughter

Scientists found that when a funny word is paired with chuckles there is a stronger reaction in the brain than the same word when followed by a neutral sound.

"This was in parts of the mind 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 responding to the laughter that follows them.

Amusement, says the expert, can be infectious.

So what does this imply for the laughter found at a holiday table?

"You laugh harder when you are familiar with people," she notes, "and laughter increases further when you are fond of them or love them."

When it comes to festive cracker puns, she says, the positive factor is more likely to be caused 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 pretext to chuckle as a group."

The Search for the Perfect Cracker Joke

Is it possible to find the perfect gag?

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

Years ago, a professor established a research project for the world's most humorous joke.

Over 40,000 jokes later, with scores lodged by 350,000 participants globally, he has a better idea than most as to what works and what fails.

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

"But they also be poor jokes, puns that make us moan," he adds.

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

"This is because if nobody laughs – it's the joke's shortcoming, not your own.

"What's interesting about the holiday cracker jokes is that none of us find them humorous.

"It creates a common experience around the table and I think it's wonderful."