What Do Holiday Cracker Jokes Do to Our Minds?

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

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

We're at a joke-testing session with a company that produces supplies for gatherings. Its repertoire features Christmas crackers.

The firm's founder grins, nearly apologetically at the joke. But the joke has been selected and will appear in future crackers.

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

The key to a good holiday cracker joke is not the same as a good gag in itself. It is all about the context - in this case, the shared amusement of the Christmas meal with grandparents, children and possibly neighbours.

"You want the gag to be something that unites the child together with the 80-year-old," she adds.

The Neuroscience Of Shared Amusement

Coming together to experience communal laughter is not only nothing new, experts argue, it is likely to be older than humanity.

"Therefore when you are laughing with people around the holiday table you are engaging in what's almost certainly a truly ancient mammal play vocalisation," says a neuroscience expert.

Shared amusement, she says, aids in make and maintain social connections between individuals.

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

"The people you talk to, and laugh with, it leads to increased levels of endorphin uptake," the professor adds.

These natural chemicals are the body's "happy chemicals" and are released both to reduce tension and discomfort and in reaction to pleasurable experiences, such as laughing with loved ones over a truly awful Christmas cracker joke.

"It's not simply chuckling at a foolish pun with a Christmas cracker," the expert says. "You are actually performing a lot of the truly important task of making, maintaining the connections you have with those you love."

Which Happens Inside the Mind?

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

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

Employing functional magnetic resonance imaging (fMRI), a kind of neural imager which indicates which parts of the mind are working harder, scientists have been able to map the regions that get more blood.

Testing entails imaging the minds of healthy participants and then exposing them to a collection of funny phrases, paired with either a neutral sound, or recorded laughter.

"During the study we got a very interesting pattern of neural activity," notes the neuroscientist.

A joke activates not just the parts of the brain in charge of auditory processing and understanding language, but also neural areas associated with both preparation and starting motion and those linked to sight and recall.

Put all of this as a whole, and individuals listening to a pun have a sophisticated set of neural responses that support the amusement we hear.

The Contagious Power of Chuckles

Researchers found that when a humorous phrase is combined with chuckles there is a stronger response in the brain than the identical word when accompanied by a neutral sound.

"This was in areas of the brain that you would use to move your expression into a grin or a chuckle," the professor says.

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

Laughter, according to the professor, can be infectious.

So what does this mean for the laughter found around a holiday gathering?

"People laugh more when you are familiar with others," she says, "and you laugh more when you are fond of them or care for them."

When it comes to Christmas cracker jokes, she explains, the feel-good factor is more probable to be triggered not by the joke itself, but from the reaction to it.

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

The Quest for the Perfect Cracker Joke

Will we ever find the ultimate gag?

Likely not, but that has not prevented experts from attempting to.

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

Over 40,000 jokes later, with scores lodged by 350,000 participants globally, he has a clearer idea than most as to what works and what does not.

The ideal Christmas cracker pun must be brief, he explains.

"They must also be poor jokes, puns that cause us to groan," he continues.

The more "awful" the joke, he states the better.

"The reason is that if no-one laughs – it's the joke's shortcoming, not yours.

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

"That's a common moment around the gathering and I think it's wonderful."