How Do Festive Cracker Gags Influence Our Brains?

"What was the price did Father Christmas's sleigh cost? Nothing, it was on the house."

This joke is met by groans that echo through a warehouse in the capital.

We're at a humor-evaluation meeting with a company that produces supplies for gatherings. Its repertoire features festive crackers.

The company's owner grins, nearly sheepishly at the joke. But the pun has made the cut and will appear in future crackers.

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

The secret to a good holiday cracker pun is not the identical as a good joke in itself. It is all about the setting - in this case, the shared amusement of the Christmas dinner table with grandparents, children and potentially friends.

"The goal is for the joke to be something that brings the eight-year-old in harmony with the 80-year-old," she adds.

The Neuroscience Of Shared Laughter

Coming together to experience shared amusement is not only nothing new, scientists say, it is likely to be pre-human.

"So when you are laughing with people at the Christmas table you are engaging in what's almost certainly a really primordial mammal play sound," explains a professor.

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

Scientists have found that a lack of these social exchanges can seriously damage both psychological and bodily health.

"Those you talk to, and laugh with, it leads to enhanced levels of endorphin uptake," she adds.

Endorphins are the brain's "feel-good compounds" and are produced both to alleviate stress and pain and in reaction to enjoyable experiences, such as laughing with loved ones over a particularly terrible Christmas cracker gag.

"It's not simply chuckling at a silly joke with a holiday cracker," the expert says. "You are actually performing a lot of the truly vital task of making, maintaining the social bonds you have with those you care about."

Which Happens Inside the Brain?

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

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

Using functional magnetic resonance imaging (fMRI), a type 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.

Testing entails scanning the minds of healthy subjects and then exposing them to a collection of funny phrases, paired with either a neutral sound, or pre-recorded chuckles.

"During the study we observed a very interesting pattern of neural activity," says the professor.

A joke stimulates not just the areas of the mind in charge of hearing and understanding speech, but also brain areas involved in both preparation and starting movement and those involved in vision and recall.

Combine these elements together, and people hearing a pun have a complex series of neural reactions that support the laughter we hear.

The Contagious Nature of Laughter

Researchers discovered that when a humorous word is combined with chuckles there is a greater reaction in the mind than the identical phrase when accompanied by a neutral sound.

"This activation occurred in parts of the mind that you would use to contort your face into a smile or a laugh," the professor explains.

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

Amusement, according to the professor, can be contagious.

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

"You laugh more when you are familiar with people," she says, "and you laugh more when you are fond of them or love them."

When it comes to Christmas cracker jokes, she says, the feel-good factor is more likely to be caused not by the gag itself, but from the reaction to it.

"It's the laughter. The joke is the dreadful holiday cracker pun, and it's just a pretext to chuckle together."

The Quest for the Perfect Festive Pun

Is it possible to find the perfect gag?

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

In 2001, a professor set up a scientific project for the planet's most humorous joke.

Over tens of thousands of gags later, with ratings lodged by hundreds of thousands of people around the world, he has a clearer idea than most as to what works and what fails.

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

"But they also need to be bad jokes, puns that cause us to moan," he continues.

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

"This is because if no-one finds it funny – it's the gag's shortcoming, not your own.

"The fascinating part about the holiday cracker jokes is that not one person find them humorous.

"It creates a shared moment at the table and I believe it's wonderful."