Why do we love a thriller?

The paper perceptual psychologist Helen Keyes has been looking at this month has found that we enjoy stories of revenge more than stories of forgiveness. Perhaps not surprising, as many of us enjoy a thriller. And this paper sheds a little light on why that might be...

Helen - When we engage with a fictional piece of work, we can approach it from an enjoyment perspective or from an appreciation perspective. And we know from our own viewing experiences that this isn't always the same thing. So for example, you might really enjoy watching repeats of Friends or watching some Love Island, but from an appreciation perspective, when you really want to have some deep meaningful connection with a narrative, you might watch a historical documentary or an arthouse movie. So we know that these are different ways to appreciate some art. These two approaches satisfy different needs that we have. So the enjoyment approach can satisfy some emotional needs, a really lower order drive to get that satisfaction from a narrative. So from an appreciation perspective that satisfies a different need, a more cognitive need, a more higher order need.

And the authors were interested in looking at retribution here. And that's because there is a lot of work done around something called the Just World hypothesis, which is an intrinsic need that we have to believe that the world is just, this is a real motivator for our behaviours. If we didn't believe the world was just, it would be hard for us to keep going and thinking, "if I put this hard work in, there's a reward for me there at the end". And "if I don't, if I transgress this boundary, there is going to be a punishment for me here". We're all invested in this idea that the world is just and therefore we have a desire to see justice done. And so these authors asked 206 students to read a number of scenarios, and these scenarios either had a narrative of under-retribution, equitable retribution, or over-retribution. You're presented with a story where a coworker has stolen 50 pounds, an under-retribution narrative would be that you then go and buy them a coffee. An equitable retribution narrative would be, you go and steal a 50 pound bottle of whiskey back from their office. And over-retribution, you would go and steal the 50 pound bottle of whiskey and also download a virus onto your coworker's computer.

Now the participants had to press a button as to whether they liked or disliked this narrative on a really basic level. And the authors also measured how quickly they press that button. But following each narrative, they also asked participants how much they enjoyed the narrative. So questions about whether it was a fun story, whether it was an entertaining story, and they asked questions about the appreciation of the narrative. So, "Was this a thought provoking, or moving, or meaningful narrative?" And what they found was people liked the equitable retribution stories the most. And this fits in what we know about a Just World hypothesis. People liked it when somebody steals 50 pounds from you, so you still 50 pounds back. That was liked the most and it was also responded to the most quickly out of all the options, suggesting it was a real intrinsic, gut-level decision, "I like this. This is fair". However, when it came to enjoyment, participants enjoyed the over-retribution scenarios significantly more than any of the other scenarios. And on the flip side of that, they appreciated the under retribution or the forgiveness narratives more than the other types of narrative.

So it suggests that, while we know what's fair and we like what's fair, when it comes to entertainment and enjoying something, we like to indulge that revenge fantasy. But if we want to have a meaningful deeper connection with something, we appreciate that deeper, slower to respond to, more thought-provoking forgiveness approach.

Katie - I feel like that makes sense, right? Because when you're talking about fiction, you're in a safe space where you can go over the top in terms of retribution.

Helen - It certainly explains the number of revenge plots in movies and books, whereas in real life, revenge plots aren't really that common. We don't usually build our lives around seeking revenge. It links in nicely with a lot of research around watching horror movies and the experience of fear or the indulging of these heightened intense emotions. Like you say, we like to do that in a safe space. So you're watching this revenge narrative and even though you know it's not fair and it's not something you'd like to see in real life, it feels nice to indulge in that heightened emotion, in this safe controlled environment, in the same way we might enjoy feeling scared.

And there's a lot to be said around the transfer of excitation here as well. So this is when you watch something that makes you scared or feel excited and that feeling, that arousal, the increased heart rate and those responses can transfer over to more positive experiences later. So if you're hanging out with your friends later, that increased arousal can really transfer into a positive experience for you.

Katie - Duncan?

Duncan - I was wondering how culturally specific this might be. Does everybody regard the same thing is just or unjust? I can imagine there are cultures or societies in the world where what they see as justice actually is sort of much harsher.

Helen - Yeah. And I think what is quite intrinsic and natural to people is the desire to see justice. But you're absolutely right. What people view as being just is very culturally dependent. And the large body of research on the Just World hypothesis explores this in great depth, what you believe to be justice is very culturally dependent. But what doesn't change is that people's drive to see whatever it is they see as just is very constant across people.

The paper Cambridge University cognitive neuroscientist Duncan has been looking at this month delves into the teenage brain...

Duncan - So traditionally about 20 or 30 years ago, we believed that brain development in humans finished at the end of childhood. So when someone's 10 or 11 years old. But we now know that actually the brain continues to develop and change throughout adolescence, which is defined as a period between puberty and adult independence, which is typically thought to be about mid twenties.... I thought you were going to ask me a question there but you're not!

Katie - No, I'm going to keep my age out of this interview!

Duncan - And so now we know that the brain continues to develop over that period of time, there are some really interesting questions to ask. So how does it continue to change, and why? And how do those changes relate to changing behaviour? So we know that as people transition from being children to adolescents, and then to adults, there are big changes in their behaviours. So for instance, the propensity for risk taking changes a lot. And how's that related to changes in the brain?

Katie - How did they seek to look into this, then? What did they do?

Duncan - So they gathered data from 298 individuals, who are aged between 14 and 26, and each person is seen multiple times, so it's a longitudinal study. And what they did for each time they saw a subject is that they would scan their brains using functional magnetic resonance imaging. And what this is able to do is track fluctuations in brain activity in multiple different regions at once. And so with these scans, across multiple different time points, at different ages, they were able to measure how well different brain areas are connected with each other. So for example, if you have two brain areas and the activity of those two areas fluctuates together, even though they're anatomically separate from each other, that implies those two brain regions are functionally connected to each other.

So you can imagine if we had scans for each person at multiple points in time, we could then chart the changes in how different brain areas are connected to each other, as the person is getting older. And this is what they did, and they found that there were multiple different changes in connectivity and they could group those changes into two classes. The first class was a set of brain regions where areas that are strongly connected just become more strongly connected. A bit like the rich become richer. And those areas are involved in things like motor control, vision, listening skills. But they can be distinguished from a second class of brain regions, areas that are well connected become less well-connected, and areas that are not well-connected become more strongly connected over time, as if what's actually happening is that there's a reorganisation in how these brain areas are connected.

Now interestingly, the second class of brain regions we know to be involved in higher order thinking skills, things like memory for your personal events, social skills and social cognition. And so what the authors are able to show is that there are these two separate types of brain development that are going on during adolescence; some areas that just become more embedded or the established connections just become stronger, and other areas where there's a massive reorganisation in which areas are connected to which areas. And this seems to mirror or match on to differences in cognitive skills.

Katie - Was there much variation between people? I'm wondering if the bits of the brain that you're talking about develop at different rates depending on the individual.

Duncan - Yeah, there's massive variability. So the headlines that you'll get in a paper like this describe the group average results. But if you dig down and look at the figures, you'll see that there are individual data points corresponding to individual participants, and that gives you a real window onto the variability. So there's a massive variability and that's why whenever we describe when adolescence starts and ends, it's group average. So for some people we would characterise their adolescence of having ended much later and others much earlier.

Katie - How significant would you say this result is?

Duncan - I think this characterisation of there being two types of brain development over this period of time is really, really interesting, because you can imagine that the genetic underpinnings of these different types of development could be different, and that might provide a really important window on the genetic underpinnings of differences in, say, social cognition or the susceptibility for different types of mental health difficulty that we know have an onset during adolescence. So I think that's really interesting.

But there are also lots of unanswered questions. So for example, it could be that all brain regions go through this disruptive phase and then this conservative phase, and that actually what the authors have captured here is that areas involved in social cognition and areas in the frontal cortex and the parietal cortex just mature much more slowly. And so you're capturing their disruptive phase before they get to their conservative phase. Whereas areas in like the motor cortex or in vision, they've already been through their disruptive phase, it happens much younger, and now they're in their conservative phase, which is a little bit different from the way the authors describe it.