"How much did Santa's sleigh cost? Nothing, it was on the house."
This one-liner is met by groans that resonate through a warehouse in London.
This describes a humor-evaluation meeting with a company that makes supplies for gatherings. Its catalogue features Christmas crackers.
The firm's founder grins, nearly apologetically at the gag. But the joke has been selected and will feature in future crackers.
"You measure the joke by the number of moans and the loudness of the groans at the table," the founder says.
The secret to a good Christmas cracker joke is not the identical as a good gag in itself. It is all about the setting - in this instance, the shared amusement of the holiday dinner table with grandparents, kids and potentially neighbours.
"You want the joke to be something that brings the eight-year-old together with the 80-year-old," she adds.
Coming together to enjoy communal amusement is not only ancient, scientists 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 very likely a truly primordial mammal social vocalisation," says a neuroscience expert.
Communal laughter, she says, aids in make and maintain social connections between individuals.
Researchers have found that a lack of these social exchanges can seriously harm both psychological and bodily well-being.
"The people you talk to, and share laughter with, it results in increased levels of endorphin uptake," she continues.
These natural chemicals are the body's "feel-good compounds" and are released both to alleviate tension and discomfort and in response to pleasurable activities, such as laughing with loved ones over a particularly terrible Christmas cracker gag.
"It's not simply laughing at a silly joke with a holiday cracker," she states. "You are in fact performing a lot of the truly important work of building, preserving the social bonds you have with those you care about."
But what is truly happening within the mind when we hear a joke?
A tremendous amount happens in reaction to humour, it transpires.
Using functional magnetic resonance imaging (fMRI), a kind of neural imager which indicates which areas of the brain are working harder, scientists have been able to chart the areas that get more blood flow.
Testing entails imaging the minds of volunteer participants and then subjecting them to a collection of humorous phrases, accompanied by either a neutral sound, or recorded chuckles.
"During the study we got a very fascinating pattern of neural activity," notes the professor.
A gag activates not just the areas of the mind responsible for hearing and understanding language, but also neural areas associated with both preparation and initiating motion and those involved in sight and memory.
Combine all of this as a whole, and individuals hearing a joke have a complex set of brain reactions that underpin the laughter we hear.
Scientists found that when a funny word is paired with laughter there is a stronger response in the mind than the identical word when accompanied by a non-emotional sound.
"This was in areas of the mind that you would employ to move your face into a smile or a laugh," the professor explains.
It means people are not just responding to funny words, they are reacting to the laughter that accompanies them.
Laughter, says the expert, can be contagious.
So what does this mean for the laughter found around a holiday table?
"People laugh harder when you know people," she notes, "and you laugh further when you like them or love them."
When it comes to festive cracker jokes, she says, the feel-good factor is more probable to be triggered not by the gag in itself, but from the response to it.
"It's the laughter. The joke is the terrible holiday cracker joke, and it's just a reason to laugh as a group."
Will we ever discover the ultimate joke?
Likely not, but that has not prevented experts from trying to.
In 2001, a psychologist set up a research project for the planet's funniest gag.
Over 40,000 jokes later, with scores provided by hundreds of thousands of people globally, he has a clearer idea than most as to what succeeds and what does not.
The perfect festive cracker joke must be short, he says.
"But they also need to be bad gags, puns that make us groan," he continues.
The increasingly "awful" the gag, he states the more effective.
"This is because if nobody finds it funny – it's the gag's shortcoming, not yours.
"The fascinating part about the Christmas cracker jokes is that none of us considers them funny.
"That's a shared experience at the gathering and I think it's wonderful."
A seasoned gambling analyst with over a decade of experience in casino gaming and slot machine strategy development.
