What Do Christmas Cracker Puns Do to The Brain?

"What was the price did Santa's sled cost? Nothing, it was on the house."

This one-liner is met by groans that echo through a storage facility in London.

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

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

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

The secret to a great holiday cracker pun is not the identical as a good gag in itself. It is entirely about the context - in this instance, the communal amusement of the Christmas dinner table with grandparents, children and potentially friends.

"You want the gag to be something that unites the child in harmony with the grandparent," she adds.

The Neuroscience Behind Communal Amusement

Gathering to enjoy shared amusement is not only nothing new, experts say, it is likely to be pre-human.

"Therefore when you are laughing with others at the Christmas dinner you are dropping into what's very likely a truly primordial mammalian social vocalisation," says a professor.

Communal laughter, she says, helps make and maintain social bonds between individuals.

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

"The people you converse with, and share laughter with, it leads to increased levels of endorphin uptake," she continues.

Endorphins are the body's "feel-good compounds" and are produced both to reduce stress and pain and in response to pleasurable activities, such as laughing with friends over a truly terrible Christmas cracker gag.

"It's not simply chuckling at a silly joke with a Christmas cracker," she states. "You are actually doing a lot of the truly important work of making, maintaining the connections you have with the people you care about."

What Happens Inside the Brain?

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

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

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

Testing involves imaging the brains of healthy participants and then exposing them to a collection of humorous words, accompanied by either a neutral sound, or pre-recorded laughter.

"In the scanner we observed a really interesting pattern of neural activity," notes the neuroscientist.

A joke stimulates not just the parts of the mind in charge of hearing and interpreting speech, but also neural regions involved in both planning and initiating motion and those linked to vision and memory.

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

The Contagious Nature of Laughter

Researchers discovered that when a funny word is combined with chuckles there is a greater response in the mind than the identical phrase when followed by a non-emotional sound.

"This was in parts of the brain that you would employ to contort your face into a smile or a laugh," the professor explains.

It indicates people are not just responding to funny jokes, they are reacting to the laughter that follows them.

Amusement, according to the expert, can be infectious.

So what does this mean for the laughter found at a holiday table?

"People laugh harder when you know people," she notes, "and laughter increases more when you like them or care for them."

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

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

The Quest for the Ideal Cracker Joke

Is it possible to find the ultimate joke?

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

In 2001, a professor established a scientific search for the world's funniest gag.

Over tens of thousands of jokes later, with scores provided by hundreds of thousands of participants globally, he has a better idea than many as to what succeeds and what does not.

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

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

The more "terrible" the joke, he says the more effective.

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

"The fascinating part about the holiday cracker puns is that none of us find them funny.

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