Tyrannosaur, Breaking the Waves and Schindler’s List might make you reach for the tissues, but psychologists say they have found a reason why traumatic films are so appealing.

Researchers at Oxford University say that watching traumatic films boosts feelings of group bonding, as well as increasing pain tolerance by upping levels of feel-good, pain-killing chemicals produced in the brain.

“The argument here is that actually, maybe the emotional wringing you get from tragedy triggers the endorphin system,” said Robin Dunbar, a co-author of the study and professor of evolutionary psychology at the University of Oxford.

Previous research has found that laughing together, dancing together and working in a team can increase social bonding and heighten pain tolerance through an endorphin boost. “All of those things, including singing and dancing and jogging and laughter, all produce an endorphin kick for the same reason - they are putting the musculature of the body under stress,” said Dunbar.

Being harrowed, he adds, could have a similar effect. “It has turned out that the same areas in the brain that deal with physical pain also handle psychological pain,” said Dunbar.

Writing in the journal Royal Society Open Science, Dunbar and colleagues describe how they set out to unpick whether our love of storytelling, a device used to share knowledge and cultivate a sense of identity within a group, is underpinned by an endorphin-related bonding mechanism.



To explore the possibility, the researchers split 169 participants into groups composed largely of people they did not know, and showed them the traumatic drama Stuart: A life backwards which is based on the true story of a disabled, homeless drug addict and alcoholic.

A control group of 68 individuals was shown, two documentaries back to back - one on natural history and the other on the geology and archaeology of Britain.

Before and after seeing the films, participants were asked to indicate through various scales their mood, together with their feelings of belonging towards other members of their group. A number of participants were also asked to complete an exercise to gauge their pain tolerance - the wall-sit test, involving squatting with their back against a wall for as long as possible.

With increased levels of pain tolerance linked to the release of potent pain-killing chemicals known as endorphins, the test offered scientists an indirect way of gauging changes to endorphin levels in the brain.

“What one wants to know is does your response to one film change in a different way to your response to the other,” said Dunbar.

The results reveal that those who watched the traumatic film had, on average, a strong negative change to their mood, while those who watched the documentaries showed only a slight change in both positive and negative markers, which the researchers attribute to boredom.

They also found that, on average, the pain tolerance of those who watched the traumatic movie increased by 13.1%, whereas those who watched the documentaries experienced a decrease in pain threshold of 4.6%. The upshot is that the traumatic film boosted pain thresholds by nearly 18% compared to the “control” scenario. What’s more, those who showed an increase in pain tolerance also had increased feelings of group bonding, despite their mood becoming less positive.

But not everyone showed an emotional response to Stuart: A life backwards. Some viewers showed a decrease in pain threshold, together with no change in their social bonding.

“This is probably true of everyday life - some people get very moved emotionally by some event that happens while other people look blankly on and say ‘what is the fuss?’” said Dunbar.

While further research is needed to look at a wider range of films and other influences, such as musical scores, Dunbar says the results suggest that watching traumatic films increases endorphin levels in the brain, boosting pain tolerance and increasing the sense of bonding with others in the group.

Prof Sophie Scott, group leader of the speech communication neuroscience group at the Institute of Cognitive Neuroscience, University College London, said it was striking that traumatic films, like laughter, appear to produce a social bonding effect.

“It suggests that it not simply [with] positive emotions that you have this bonding effect - maybe there is something about a shared emotional experience which is really changing how your endorphins are being taken up and making you feel closer to people,” she said, adding that exploring the effects of anger or disgust could help to tease apart whether the effect was down to particular emotions, or rather the sharing of them.

But Scott, who wasn’t involved in the research, said she isn’t convinced that Dunbar and colleagues have discovered the foundations of our love of storytelling. “Stories are everything for humans - if we can fit something into a story we will do. We understand things better if they fit to stories, we remember things better if they fit to stories,” she said. “I don’t know if you are going account for that simply with shared emotions.”