What Do Christmas Cracker Puns Influence Our Brains?

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

This joke is greeted with moans that echo through a storage facility in London.

We're at a joke-testing session with a company that makes products for gatherings. Its repertoire includes Christmas crackers.

The firm's owner grins, almost apologetically at the gag. But the pun has made the cut and will feature in upcoming crackers.

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

The secret to a good holiday cracker pun is not the same as a good gag in itself. It is all about the setting - in this instance, the communal amusement of the Christmas meal with grandparents, children and possibly friends.

"You want the joke to be a thing that brings the eight-year-old in harmony with the grandparent," she adds.

The Science Behind Shared Laughter

Coming together to enjoy shared amusement is not only ancient, scientists argue, it is probably to be older than humanity.

"Therefore when you are laughing with others at the Christmas dinner you are engaging in what's very likely a truly primordial mammalian play vocalisation," explains a professor.

Shared amusement, she explains, helps make and maintain social bonds between individuals.

Researchers have discovered that a absence of these interactions can seriously damage mental and physical well-being.

"The people you converse with, and laugh with, it leads to increased amounts of 'happy chemical' release," the professor adds.

Endorphins are the body's "feel-good compounds" and are produced both to alleviate stress and pain and in reaction to pleasurable experiences, such as chuckling with loved ones over a particularly awful festive cracker joke.

"It's not simply chuckling at a foolish joke with a Christmas cracker," she says. "You are actually doing a lot of the really vital task of making, maintaining the connections you have with the people you care about."

Which Happens In the Brain?

But what is truly happening within the brain when we listen to a gag?

A tremendous amount occurs in response to comedy, it transpires.

Using functional magnetic resonance imaging (fMRI), a kind of brain scanner which shows which areas of the mind are more active, scientists have been able to chart the regions that get more blood flow.

The research entails imaging the minds of volunteer participants and then subjecting them to a collection of humorous phrases, accompanied by either a non-emotional sound, or recorded laughter.

"During the study we got a very fascinating activation pattern of activation," notes the neuroscientist.

A joke stimulates not just the areas of the mind in charge of hearing and understanding language, but also neural areas associated with both preparation and initiating motion and those linked to sight and memory.

Combine these elements as a whole, and individuals listening to a pun have a complex series of neural reactions that support the laughter we experience.

The Contagious Power of Laughter

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

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

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

Amusement, says the expert, can be contagious.

So what does this imply for the laughter heard around a holiday gathering?

"You laugh more when you know others," she says, "and you laugh more when you like them or love them."

When it comes to Christmas cracker puns, she explains, 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 joke is the dreadful holiday cracker pun, and it's just a reason to laugh as a group."

The Search for the Ideal Cracker Joke

Will we ever discover the ultimate joke?

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

In 2001, a psychologist set up a scientific project for the world's funniest joke.

More than 40,000 jokes submitted, with scores lodged by hundreds of thousands of participants globally, he has a better idea than many as to what works and what fails.

The perfect Christmas cracker joke must be short, he says.

"They must also need to be bad jokes, puns that make us moan," he adds.

The more "awful" the gag, he says the more effective.

"The reason is that if nobody laughs – it's the gag's fault, not yours.

"The fascinating part about the Christmas cracker jokes is that none of us considers them funny.

"That's a common moment around the table and I think it's lovely."