What Do Festive Cracker Puns Affect The Brain?

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

This joke is greeted with groans that echo through a warehouse in London.

We're at a joke-testing session with a company that produces products for social events. Its repertoire features Christmas crackers.

The company's founder grins, nearly sheepishly at the gag. But the pun has been selected and will feature in upcoming crackers.

"You measure the gag by the volume of groans and the loudness of the groans around the table," she says.

The secret to a great Christmas cracker pun is not the identical as a stand-up joke per se. It is all about the context - in this case, the communal amusement of the holiday dinner table with grandparents, kids and potentially friends.

"You want the joke to be a thing that unites the child together with the 80-year-old," she states.

The Neuroscience Behind Shared Amusement

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

"So when you are laughing with others at the Christmas dinner you are dropping into what's almost certainly a truly primordial mammal social vocalisation," says a professor.

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

Scientists have found that a absence of such interactions can seriously damage both psychological and bodily health.

"The people you talk to, and laugh with, it results in enhanced amounts of 'happy chemical' release," the professor continues.

These natural chemicals are the body's "happy chemicals" and are produced both to alleviate tension and discomfort and in reaction to pleasurable experiences, such as chuckling with friends over a truly terrible Christmas cracker gag.

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

What Happens Inside the Mind?

But what is truly happening within the mind when we hear a joke?

A tremendous amount occurs in reaction to comedy, it turns out.

Employing functional magnetic resonance imaging (fMRI), a kind of neural imager which shows which areas of the mind are more active, researchers have been able to chart the regions that receive more blood flow.

Testing involves imaging the minds of volunteer participants and then exposing them to a collection of humorous words, accompanied by either a non-emotional sound, or recorded laughter.

"During the study we observed a very fascinating activation pattern of neural activity," notes the professor.

A joke activates not just the areas of the mind responsible for hearing and understanding speech, but also brain areas associated with both preparation and starting movement and those involved in vision and memory.

Put all of this as a whole, and individuals hearing a joke have a sophisticated series of neural reactions that support the laughter we experience.

The Infectious Nature of Chuckles

Scientists found that when a funny phrase is paired with chuckles there is a stronger reaction in the mind than the identical phrase when followed by a non-emotional sound.

"This was in areas of the mind that you would use to contort your face into a smile or a chuckle," she explains.

It indicates we are not just responding to funny jokes, they are responding to the amusement that accompanies them.

Laughter, according to the expert, can be contagious.

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

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

When it comes to Christmas cracker puns, she says, the positive effect is more likely to be caused not by the joke itself, but from the reaction to it.

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

The Search for the Ideal Cracker Joke

Is it possible to find the perfect gag?

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

Years ago, a psychologist set up a research project for the planet's most humorous joke.

More than tens of thousands of gags later, with ratings lodged by hundreds of thousands of people globally, he has a clearer idea than many as to what works and what does not.

The ideal festive cracker pun needs to be brief, he explains.

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

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

"The reason is that if no-one laughs – it's the gag's shortcoming, not your own.

"What's interesting about the holiday cracker jokes is that none of us considers them humorous.

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