Dean Burnett looks at what we know

Where does humour and laughter come from in the brain? It’s a good question, but not one that has a simple answer. It’s hard to deny that they’re very important to people. A good sense of humour, or ‘GSOH’, is a default requirement on dating profiles the world over. This is arguably redundant, because who wants a date with a bad sense of humour? Saying ‘I’m looking for someone who thinks stand-up comedy is the work of Satan but guffaws at burning kittens.’

However, what counts as a ‘good’ sense of humour varies wildly between individuals, hence we get stand-up enthusiasts and regular Chortle readers expressing fury and bafflement at the success of Mrs Brown’s Boys. And here you have a major problem; the subjective nature of humour makes it very tricky to study scientifically. 

You might think it should be simple. Just use the modern go-to approach when you want to see how the brain does something and use an fMRI scanner. Say you want to find out how the brain processes the colour red? You put someone in a scanner, show them the colour red, then monitor the activity of their brain while they are ‘perceiving the colour red’, which is the desired response. Why not do that with humour? 

Except it’s obviously more complicated. The typical conscious brain is invariably doing several hundred things at once (processing all the sensory information, contemplating, thinking, remembering, diverting attention etc.) , and an fMRI scan shows all the activity produced as a result of these things and all the processes they involve. So if you’re looking at someone’s brain in a scanner while showing them the colour red, how do you know the activity you’re detecting is caused by processing the colour red, or something else entirely, like a stray thought or sensation of claustrophobia? (fMRI scanners are quite cramped). 

To get around this, you need to scan as many different people as possible while showing them the colour red. If the same bit of the brain lights up each time in 50 (ideally very different) people, then it’s far more likely to be that bit which processes perception of the colour red. For this to be valid though, you have to use the same stimulus each time; it’s no good showing one subject something red thing and the next something burgundy, and the next something burnt orange, and so on. For these experiments to work, you need to show as many people as possible something that will reliably produce the same brain activity you’re looking for each time. 

This means if you want to use a brain scanner to study laughter and humour, you’d ideally need something that is guaranteed to make everybody laugh, 100 per of the time. Such a thing has eluded the finest comedy minds since the dawn of civilisation, so to expect scientists, who aren’t exactly known for their prowess with humour, to come up with such a thing is a ridiculous ask. 

This is just one reason why humour and laughter (and how they’re processed by the brain) are such tricky things to study. Not that scientists are totally put off. Professor Sophie Scott from UCL is particularly notable for her efforts to understand how and why we laugh, and this very website often flags up studies relating to humour and comedy, albeit ones with dubious conclusions and/or involving rather ‘interesting’ methods (unicycles, anyone?). But often, humour and laughter are used as a means to study something else (the differences between genders, or the prevalence of mental health issues etc). Interesting perhaps, but it doesn’t tell us much about how or why we laugh or find things funny. Humour is more a tool, than the focus of such research.

Why we laugh is a question that’s been puzzled over by great minds over the centuries. Nietzsche argued that laughter is an inherent reaction to the sense of existential loneliness and mortality felt by all humans. But then, that’s the sort of thing Nietzsche said a lot, although I’ve met open spots with similarly bleak outlooks. 

The ‘relief' theory of laughter was pioneered by people like Sigmund Freud, and argues that laughter is a mechanism for releasing ‘psychic energy’ caused by a build-up of nervous tension. It could be tension caused by someone in imminent physical danger, which would explain why slapstick is a rich source of humour; there’s physical ‘risk’, but the individual never comes to harm, so the tension can ‘dissipate’ via laughter. Someone slips on ice and lands on their arse? Funny. Someone slips on ice and lands on their head, cracking their skull? Not funny. The danger was real, there’s no tension to dissipate. 

There’s also more abstract tension, which supposedly comes from being presented with scenarios, set-ups or wordplay that violates our norms or expectations. Jokes usually aren’t logical, and uncertainty isn’t something our brains enjoy dealing with. When the punchline is delivered, this explains the situation so we experience this same ‘relief’, and have a pleasurable laugh as a reward for getting rid of the uncertainty. This would also explain why a joke is never as funny the second time; the uncertainty has been neutered, it’s predictable now.

These approaches focus on what’s going on inside our head, whereas most psychologists would agree that laughter and humour is very much a social thing, strongly influenced by those around us. Studies suggest we’re thirty times more likely to laugh when we’re part of a group, as opposed to alone. We’ve evolved to openly and loudly laugh when amused, and it’s clearly very infectious, so obviously has excellent unifying and bonding effects. People are also very sensitive to fake laughter, which may explain why canned laughter gets so many people’s backs up. 

It’s not all friendly though. One theory is that we laugh at people to demonstrate our superiority to them; it’s a way of saying ‘you screwed up, so I will make it obvious that I find you amusing, because that shows I’m better than you’. An interesting theory perhaps, but clearly not the whole story. The thousands of people watching Kevin Bridges in his arena gigs aren’t all thinking, ‘Look at this loser. I’m better than this guy’. 

With regards to "where" in the brain humour and laughter comes from, it’s almost certainly not one particular area that is responsible for it all, more a network of widespread regions all working together. You’ve got the hippocampus for memory storage and recognition allowing us to recognise when something is unusual or ridiculous, the amygdala for processing strong emotional reactions, the language processing areas in the parietal lobe for wordplay and puns and the like, the frontal lobes for focus and attention and calculation, and probably a whole suite of other bits chiming in as well. 

One interesting study looked at deaf subjects. With people lucky enough to have intact hearing, the patterns of laughter during joke telling are very consistent. We only laugh during pauses in sentences or at the punchlines, because if we laugh during the telling of the joke it would obscure it, as it’s a form of sound-based communication. This doesn’t apply to people who tell jokes and laugh using sign language, but the study found that they still laugh in the same intervals and pauses regardless. 

It seems that, when it comes to comedy, even the underlying workings of the brain support the notion that timing is everything.

• Dean Burnett is a doctor of neuroscience, sometimes stand-up comic and science writer for the Guardian. This article is adapted from his debut book The Idiot Brain, published now by Guardian Faber, priced £12.99. Click here to buy from Foyles.

Published: 25 Feb 2016