How Do Holiday Cracker Gags Influence Our Brains?

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

This joke is met by moans that echo through a warehouse in the capital.

This describes a joke-testing meeting with a company that produces products for gatherings. Its catalogue includes Christmas crackers.

The company's founder grins, nearly apologetically at the gag. But the joke has been selected and will feature in future crackers.

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

The key to a good Christmas cracker pun is not the same as a good joke per se. It is entirely about the context - in this instance, the communal amusement of the holiday dinner table with grandparents, children and potentially neighbours.

"The goal is for the joke to be a thing that brings the child in harmony with the 80-year-old," she adds.

The Neuroscience Behind Shared Laughter

Gathering to experience shared amusement is not only ancient, experts say, it is probably to be pre-human.

"Therefore when you are chuckling with people around the holiday dinner you are dropping into what's very likely a truly ancient mammalian social vocalisation," says a professor.

Communal laughter, she says, aids in forge and strengthen social connections between people.

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

"The people you converse with, and share laughter with, it leads to enhanced levels of endorphin uptake," the professor adds.

These natural chemicals are the body's "feel-good compounds" and are released both to alleviate tension and discomfort and in reaction to enjoyable experiences, such as chuckling with loved ones over a particularly awful Christmas cracker joke.

"It's not simply laughing at a foolish pun with a holiday cracker," she says. "You are actually performing a lot of the really important task of building, preserving the connections you have with the people you love."

What Happens In the Brain?

But what is actually happening within the brain when we listen to a joke?

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

Using functional magnetic resonance imaging (fMRI), a type of brain scanner which indicates which areas of the mind are working harder, researchers have been able to map the areas that receive more blood.

The research involves imaging the brains of volunteer subjects and then subjecting them to a database of funny words, paired with either a non-emotional sound, or pre-recorded laughter.

"In the scanner we observed a very interesting pattern of activation," says the neuroscientist.

A gag activates not just the areas of the mind in charge of hearing and understanding speech, but also neural areas associated with both planning and initiating movement and those involved in vision and memory.

Combine these elements as a whole, and people listening to a pun have a complex set of brain reactions that support the amusement we hear.

The Infectious Power of Laughter

Scientists discovered that when a humorous phrase is paired with chuckles there is a greater reaction in the brain than the identical phrase when followed by a non-emotional sound.

"This activation occurred in areas of the brain that you would use to contort your face into a grin or a chuckle," the professor explains.

It means people are not just reacting to humorous jokes, they are reacting to the amusement that accompanies them.

Laughter, according to the expert, can be infectious.

So what does this imply for the laughter found around a Christmas table?

"You laugh harder when you are familiar with others," she says, "and you laugh more when you like them or care for them."

When it comes to Christmas cracker jokes, she says, the positive factor is more likely to be triggered not by the joke in itself, but from the reaction to it.

"The laughter is key. The gag is the terrible Christmas cracker pun, and it's just a pretext to laugh together."

The Search for the Ideal Festive Pun

Will we ever discover the perfect gag?

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

Years ago, a psychologist set up a scientific project for the world's most humorous gag.

Over tens of thousands of jokes later, with scores provided by 350,000 people around the world, he has a better understanding than many as to what works and what fails.

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

"They must also be bad jokes, jokes that cause us to moan," he adds.

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

"This is because if nobody laughs – it's the joke's fault, not yours.

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

"It creates a common experience at the gathering and I believe it's lovely."