How Do Holiday Cracker Puns Do to Our Minds?

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

This one-liner is met by moans that echo through a warehouse in London.

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

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

"The success is gauged by the joke by the number of moans and the intensity of the groans at the table," she says.

The key to a great Christmas cracker pun is not the identical as a stand-up gag per se. It is all about the setting - in this case, the communal amusement of the Christmas dinner table with grandparents, children and possibly neighbours.

"You want the joke to be something that unites the child together with the grandparent," she adds.

The Neuroscience Of Communal Amusement

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

"So when you are laughing with others at the holiday dinner you are engaging in what's very likely a truly primordial mammalian social sound," says a professor.

Shared laughter, she says, aids in forge and strengthen social bonds between individuals.

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

"Those you converse with, and share laughter with, it results in increased levels of 'happy chemical' uptake," the professor adds.

Endorphins are the body's "happy chemicals" and are released both to reduce stress and pain and in response to enjoyable activities, such as chuckling with loved ones over a particularly awful Christmas cracker gag.

"You're not just chuckling at a foolish joke with a Christmas cracker," the expert says. "You are in fact doing a lot of the truly 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 joke?

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

Using brain scanning technology, a kind of neural imager which shows which parts of the brain are more active, scientists have been able to chart the regions that get more blood flow.

The research entails scanning the minds of volunteer subjects and then subjecting them to a collection of funny phrases, accompanied by either a neutral sound, or pre-recorded laughter.

"During the study we observed a very fascinating pattern of activation," says the professor.

A gag activates not just the areas of the mind responsible for hearing and interpreting language, but also neural areas involved in both planning and initiating movement and those involved in sight and recall.

Put these elements as a whole, and individuals hearing a joke have a sophisticated series of brain reactions that support the amusement we hear.

The Infectious Nature of Chuckles

Scientists found that when a humorous word is combined with chuckles there is a stronger reaction in the mind than the same word when accompanied by a non-emotional sound.

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

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

Amusement, says the expert, can be contagious.

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

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

When it comes to festive cracker puns, she says, the feel-good factor is more likely to be caused not by the joke in 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 laugh together."

The Search for the Ideal Festive Pun

Will we ever discover the perfect joke?

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

Years ago, a professor established a scientific search for the planet's most humorous joke.

Over tens of thousands of gags submitted, with scores lodged by 350,000 participants around the world, he has a better understanding than many as to what succeeds and what does not.

The ideal Christmas cracker joke must be brief, he says.

"But they also be poor gags, puns that make us moan," he continues.

The increasingly "terrible" the joke, he says the better.

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

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

"That's a shared moment around the gathering and I think it's lovely."