We say that our feelings can be like a rollercoaster – and, as it turns out, the psychology of our emotions has influenced rollercoaster design from the beginning. Thrill engineer Prof Brendan Walker talked to us about fairground rides, adrenaline and adventure, and why we seek out the seemingly scary…
What does a ‘thrill engineer’ do?
I came up with the term because I really like the idea of combining the objective practice of engineering, creating things with rules, with the subjective elements of human emotions. So, being a thrill engineer means I craft extreme, human emotional experiences, using design principles.
What psychological levers are you trying to pull when you design a rollercoaster?
If I put you on a rollercoaster and blindfolded you, your body’s levels of arousal would pretty precisely track the changes in acceleration forces felt around the ride.
Rollercoasters are successful because they really grab hold of that element of arousal and, because it’s so tightly interlinked with physical sensations that we get from the world, we can almost force an emotional experience by the very shape of the rollercoaster.
We have 43 different muscle groups in the face, and any combination can express different emotions that we’re feeling.
I was interested in using the techniques that computers use to detect human expressions, to understand people’s emotions on rides. Dr James Condron, from Massachusetts Institute of Technology, created a galvanic skin-response monitoring device, and worked with me on a project.
We put people on fairground rides and used the technology to fire a camera when the device measured high levels of arousal. The 10 portraits from that project absolutely set in stone the range of emotions experienced across different ride types.
On a ride, people’s emotions are constantly in flux – between extreme excitement, delight, joy, happiness all the way through to terror, horror, sometimes boredom as well. But the critical thing about thrill is that thrill isn’t an emotion itself. It is the change in emotions.
There’s a fine line between ‘fun’ fear, and believing you’re really under threat…
Absolutely. If I were to do an experiment through a university’s psychology department, if I said that I was going to make people believe that they’re really in danger… I would be in ethics committees for years.
Yet in entertainment, there’s this sort of tacit understanding, a kind of unspoken contract between people who go seeking entertainment and those who provide it. The people going into amusement parks are saying, “I want to be challenged. I want to be taken to the edge, but I trust as part of this agreement, you are agreeing to ultimately keep me safe.”
Why are some people more sensation-seeking than others?
You can look at the personality traits of people who tend to go to theme parks and on rollercoasters. In fact, I usually quote Marvin Zuckerman, a professor at the University of Delaware. I think of him as the grandfather of thrill-seeking.
He classified four different dimensions to sensation-seeking. One is thrill- and adventure-seeking, which is very much to do with rollercoasters and that kind of high adrenaline experience. Another one is experience-seeking – people who like unusual experiences, like theatre, circus and magic.
The other one is disinhibition, so people who might like to scream on a rollercoaster really let themselves go. And there’s also resistance to boredom, which is a great measure to have, particularly if you’re going to queue for an hour to get on a rollercoaster that lasts only two minutes.
Also, our enjoyment depends on our perceptions of risk, whether we’re novelty-seeking, and, critically, how we ride rollercoasters. If I went on a ride with you, we might have a great time because we’re good friends.
If I go on to do a very objective scientific exploration of the ride, I’ll have a different experience. If I get on it with somebody I don’t like, in the rain, I could have a miserable time. There are so many contributing factors.
You’ve been involved in rollercoaster design from the conception to the final product, right?
Yes. I have been involved in the design of rollercoasters from early inception, for example, the Wicker Man at Alton Towers. All we knew was that they had a footprint of land and we had an audience who were demanding a new rollercoaster. After that, there were no other prescriptions for what we would make.
In a situation like that, there are several things we look at. One is what are the cultural trends in society? What novel technologies are out there? What are people talking about?
This is where the idea of a wooden rollercoaster came in. In America they’re very popular but in the UK, we only have one or two. Then the theme of the Wicker Man and the horror scenario started to evolve.
Then there are the rides like TH13TEEN at Alton Towers, where it had been pretty much finalised and I just worked on one particular feature. If you don’t know TH13TEEN, you go in and – this isn’t a spoiler by the way, I think most people know this before they get on – you go into the dark tunnel, the ride stops and then it falls. Your carriage falls, vertically, through the dark.
Alton Towers wanted to know, was this going to be thrilling? How far in the dark should we drop people? There’s quite a precise calculation – we can work out how quickly the brain processes novel information, such as a sudden drop in the dark, and how long it takes to translate that into action, such as screaming.
That’s quite a critical calculation, because if you make it too short, people aren’t going to be thrilled. If you make it too long, well for every extra inch of steelwork you create, it costs tens of thousands of pounds. There’s not only psychological modelling, but also economics modelling behind the whole thing.
In any other situation, a drop like the one on TH13TEEN would frighten me. How does that turn into thrill and excitement?
Yeah, I feel like my job is terrorising people! As animals, we have a really strong relationship with thrill. In evolutionary terms, thrill has evolved as a mechanism to reward the persistence of life.
Now, that’s evading danger – not being killed or maimed – all the way through to reproduction, sating hunger, quenching thirst, chasing prey. These are all quite exciting things. And in modern life, in our Western world, we’re lucky that we rarely experience those extremes.
But to feel thrilled is to feel truly alive. In a world where we don’t feel thrilled, we feel flat, we don’t feel excited. So, part of the appeal of theme parks and rollercoasters is replacing those mechanisms that used to naturally exist.
But whereas in the wild, we truly were faced with real dangers, the job of a theme park is to create the perception of danger. The actual danger of the theme park – well, you’re more likely to fall off a donkey in Skegness than have any accidents on a theme park ride.
Do you consider yourself a thrill-seeker?
I’d always thought of myself as a real thrill-seeker. But I think my perceptions of risk are quite low.
I actually went to see if I had the ‘thrill-seeking gene’, as research suggests our reasons for thrill-seeking can be partly put down to genetics.
When we experience pleasure, the body releases dopamine. Dopamine binds to receptors in the body, which gives us this sense of euphoria. This is the reward feedback we get, and it can be a problem because it can lead to addictive behaviour. But in rollercoasters, think about it: we rely on this burst of dopamine.
Some people have a defect, called a polymorphism, version of a dopamine receptor gene, which means that the receptor can’t bind to dopamine as efficiently. So, the body needs to produce more dopamine to give the receptors a better chance of picking it up.
I found that I have this polymorphism and I am a bona fide thrill-seeker. I’m not unusual – in the UK, around 1 in 30 people have this polymorphism.
But when you go to the US and in Australia, the proportion is about 1 in 20. This is thought to be because the people who had this thrill-seeking gene were more likely to be adventurers, more likely to go and colonise these other places.
But then you look at other nations such as China, where I think the occurrence is about 1 in 60. They have a different attitude to adventure, and going out and seeking new places. So, it’s quite fascinating once you start charting on a global scale who has got this polymorphism.
Hurtling around a track, with forces up to 5g, can be a terrifying thought…
It sure can be. But on rollercoasters, we only experience 5g for momentary periods. The way that rides have all the banking and twists and turns, that’s primarily to try to maintain the majority of the g-forces acting through the body. So – through your head, down the spine, through the seat of your pants and into the seat below you.
And that’s because we’re pretty good at withstanding g-forces in that particular plane. If you sustain that kind of force for any period of time, blacking out is a possibility. So, they [high g-forces] usually mark transitions between different forms of motion and they can be the really thrilling moments.
After the lockdown, when I can go out again, what ride would you recommend?
For my money, I would go to the fairground and I would find a ride called the Orbit. It was one of the first fairground rides which didn’t just do circles within circles, but the arms raise up and they throw you around. It’s a really compact ride, and so the motions you get are really intense.
When I found out that the people who invented that ride were more used to making oil rigs and drilling equipment, it suddenly all made sense. If you imagine diamond blades at the end of these arms, whizzing around, and the whole thing boring underneath the Channel Tunnel, I think you kind of get the idea. So, when you can, go to your local fairground, find an Orbit and get on it.
Amy is the Editorial Assistant at BBC Science Focus and looks after all things books, culture and media. She is also a regular interviewer on the Science Focus Podcast. Her interests range from natural history and wildlife, to women in STEM and accessibility tech.