What Do Holiday Cracker Gags Do to Our Brains?

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

This one-liner is greeted with moans that resonate through a storage facility in the capital.

This describes a humor-evaluation session with a company that makes supplies for gatherings. Its catalogue includes festive crackers.

The firm's owner smiles, nearly sheepishly at the joke. But the pun 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," the founder explains.

The secret to a great Christmas 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 dinner table with grandparents, children and potentially friends.

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

The Science Behind Communal Amusement

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

"Therefore when you are laughing with others around the holiday dinner you are engaging in what's almost certainly a truly primordial mammalian social vocalisation," says a professor.

Shared amusement, she says, aids in forge and strengthen social connections between individuals.

Researchers have found that a absence of such social exchanges can seriously damage mental and physical health.

"Those you talk to, and share laughter with, it results in enhanced levels of 'happy chemical' release," she adds.

These natural chemicals are the brain's "feel-good compounds" and are produced both to alleviate tension and discomfort and in response to enjoyable experiences, such as laughing with friends over a particularly terrible festive cracker gag.

"You're not just chuckling at a silly joke with a holiday cracker," the expert states. "You are actually performing a lot of the really important task of making, maintaining the connections you have with the people you care about."

Which Occurs In the Mind?

But what is actually happening inside the brain when we hear a gag?

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

Using brain scanning technology, a kind of neural imager which indicates which areas of the mind are working harder, scientists have been able to map the regions that receive more blood flow.

Testing involves scanning the minds of volunteer subjects and then subjecting them to a collection of funny phrases, paired with either a non-emotional sound, or pre-recorded laughter.

"In the scanner we got a really fascinating activation pattern of activation," says the neuroscientist.

A gag stimulates not just the areas of the brain responsible for auditory processing and interpreting speech, but also neural areas associated with both preparation and initiating motion and those involved in sight and memory.

Combine these elements together, and individuals listening to a joke have a sophisticated series of brain reactions that underpin the laughter we hear.

The Infectious Nature of Laughter

Researchers found that when a humorous word is paired with laughter there is a stronger response in the brain than the same word when followed by a neutral sound.

"This activation occurred in areas of the mind that you would employ to contort your face into a grin or a laugh," she says.

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

Laughter, according to the expert, can be infectious.

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

"People laugh more when you know people," she notes, "and you laugh more when you are fond of them or care for them."

When it comes to festive cracker puns, she explains, the feel-good effect is more likely to be triggered not by the joke in itself, but from the response to it.

"It's the laughter. The gag is the dreadful holiday cracker pun, and it's just a pretext to laugh as a group."

The Quest for the Perfect Festive Pun

Will we ever discover the ultimate joke?

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

In 2001, a professor established a scientific project for the planet's funniest gag.

Over 40,000 jokes later, with ratings lodged by 350,000 participants around the world, he has a better understanding than most as to what works and what does not.

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

"They must also need to be bad gags, puns that cause us to groan," he continues.

The more "terrible" the gag, he says the better.

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

"What's interesting about the Christmas cracker jokes is that not one person find them humorous.

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