🔗 Share this article

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

This one-liner is greeted with groans that resonate through a warehouse in London.

We're at a humor-evaluation session with a company that makes supplies for social events. Its catalogue includes Christmas crackers.

The firm's founder smiles, nearly sheepishly at the gag. But the joke has made the cut and will feature in upcoming crackers.

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

The secret to a good holiday cracker joke is not the identical as a stand-up gag per se. It is entirely about the context - in this instance, the shared amusement of the holiday dinner table with elders, kids and possibly neighbours.

"You want the joke to be a thing that brings the eight-year-old in harmony with the 80-year-old," she adds.

The Neuroscience Behind Shared Laughter

Gathering to enjoy communal amusement is not only ancient, scientists say, it is probably to be older than humanity.

"Therefore when you are chuckling with others around the holiday table you are engaging in what's very likely a really ancient mammalian play vocalisation," explains a neuroscience expert.

Shared amusement, she explains, aids in make and maintain social connections between people.

Researchers have discovered that a lack of such interactions can significantly damage both psychological and bodily health.

"The people you converse with, and laugh with, it leads to enhanced levels of endorphin release," the professor adds.

Endorphins are the brain's "happy chemicals" and are released both to reduce stress and pain and in response to enjoyable experiences, such as laughing with loved ones over a truly awful Christmas cracker gag.

"You're not just chuckling at a silly pun with a Christmas cracker," she states. "You are in fact doing a lot of the really vital work of building, preserving the social bonds you have with those you love."

Which Happens In the Mind?

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

An awful lot occurs in response to comedy, it transpires.

Employing brain scanning technology, a type of brain scanner which shows which parts of the mind are more active, researchers have been able to map the areas that get more blood.

Testing involves scanning the minds of volunteer participants and then exposing them to a collection of humorous words, accompanied by either a neutral sound, or recorded chuckles.

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

A joke activates not just the areas of the brain in charge of hearing and interpreting speech, but also brain regions involved in both planning and initiating motion and those linked to sight and memory.

Put these elements as a whole, and individuals listening to a joke have a complex set of brain reactions that underpin the laughter we hear.

The Infectious Nature of Laughter

Researchers discovered that when a funny phrase is combined with chuckles there is a stronger reaction in the mind than the identical 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 chuckle," she explains.

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

Laughter, says the expert, can be contagious.

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

"People laugh harder when you are familiar with others," she says, "and laughter increases further when you like them or love them."

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

"The laughter is key. The joke is the terrible holiday cracker pun, and it's just a pretext to chuckle together."

The Quest for the Perfect Cracker Joke

Is it possible to discover the perfect gag?

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

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

Over tens of thousands of gags later, with ratings provided by 350,000 people around the world, he has a clearer idea than most as to what works and what fails.

The ideal festive cracker pun must be short, he explains.

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

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

"This is because if no-one laughs – it's the gag's shortcoming, not your own.

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

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