How Do Festive Cracker Jokes Affect The Brain?

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

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

We're at a joke-testing meeting with a firm that makes products for social events. Its catalogue features Christmas crackers.

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

"The success is gauged by the gag by the volume of moans and the loudness of the groans around the table," she says.

The secret to a great holiday cracker joke is not the identical as a stand-up joke per se. It is all about the context - in this case, the shared laughter of the Christmas meal with grandparents, kids and possibly friends.

"You want the gag to be something that unites the eight-year-old together with the grandparent," she states.

The Science Behind Communal Laughter

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

"So when you are chuckling with others at the Christmas table you are engaging in what's very likely a really ancient mammalian play sound," says a neuroscience expert.

Shared laughter, she explains, helps make and maintain social connections between people.

Scientists have discovered that a lack of these interactions can seriously damage both psychological and bodily well-being.

"The people you converse with, and share laughter with, it results in increased levels of 'happy chemical' uptake," the professor continues.

Endorphins are the body's "happy chemicals" and are produced both to alleviate stress and pain and in response to pleasurable experiences, such as chuckling with friends over a truly terrible Christmas 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 building, preserving the connections you have with the people you love."

What Occurs In the Brain?

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

An awful lot occurs in response to humour, it turns out.

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

Testing involves scanning the minds of healthy subjects and then exposing them to a database of humorous phrases, accompanied by either a non-emotional sound, or pre-recorded chuckles.

"In the scanner we observed a really fascinating activation pattern of neural activity," says the neuroscientist.

A gag stimulates not just the areas of the brain in charge of auditory processing and interpreting speech, but also brain regions involved in both preparation and initiating motion and those involved in sight and memory.

Combine these elements as a whole, and people listening to a joke have a complex series of brain reactions that support the laughter we hear.

The Contagious Nature of Laughter

Researchers found that when a humorous word is combined with laughter there is a stronger reaction in the brain than the same word when accompanied by a non-emotional sound.

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

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

Amusement, according to the professor, can be infectious.

So what does this imply for the chuckles found at a holiday gathering?

"People laugh harder when you know people," 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 caused not by the joke in itself, but from the response to it.

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

The Search for the Perfect Festive Pun

Is it possible to find the ultimate gag?

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

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

More than 40,000 gags later, with ratings lodged by hundreds of thousands of participants globally, he has a better understanding than many as to what succeeds and what does not.

The ideal Christmas cracker joke must be short, he explains.

"But they also be bad jokes, puns that make us moan," he adds.

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

"The reason is that if nobody finds it funny – it's the joke's shortcoming, not yours.

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

"That's a common moment at the table and I think it's wonderful."