Paris—In pain? A good laugh with friends will help you deal with it courtesy of “feel-good” chemicals that flood the brain, according to a British study released on Wednesday.

Researchers conducted lab experiments in which volunteers watched either comedy clips from “Mr. Bean” or “Friends,” or nonhumorous items such as golf or wildlife programs, while their resistance to mild pain was monitored.

Another test was carried out at the Edinburgh Fringe Festival, where the volunteers watched either a stand-up comedy show or a theatrical drama.

The pain came from a deep-frozen wine-cooler sleeve slipped over a forearm, an ever tightening blood pressure cuff, or an excruciating ski exercise.

For the Fringe Festival, the volunteers were asked to do a tough exercise. They leaned against the wall with their legs at right angles, as if sitting on a straight-backed chair, before and immediately after the performance, to see if laughter had helped with the pain.

Just 15 minutes of laughter increased the level of pain tolerance by around 10 percent, the study found.

In the lab experiments, the neutral, nonfunny programming had no pain-alleviating effect at all. Nor did watching drama at the Fringe Festival.

But the study notes two important distinctions.

The only laughter that worked was relaxed, unforced laughter that creases the eyes, as opposed to a polite titter. And this kind of belly laugh is far likelier to happen when you are with others, rather than alone.

Endorphins

“Very little research has been done into why we laugh and what role it plays in society,” said Robin Dunbar, head of the Institute of Social and Cultural Anthropology at the University of Oxford.

“Using microphones, we were able to record each of the participants and found that in a comedy show, they laughed for about a third of the time, and their pain tolerance rose as a consequence,” he added.

The protection apparently comes from endorphins, a complex chemical that helps to transmit messages between neurons but also dulls signals of physical pain and psychological stress.

Endorphins are the famous product of physical exercise—they help create the “buzz” that comes from running, swimming, rowing, yoga and so on.

In laughter, the release comes from an involuntary, repeated muscular exertion that comes from exhaling without drawing a breath, the scientists believe. The exertion leaves us exhausted and thereby triggers the endorphins.

Great apes are also believed to be able to laugh but, unlike humans, they breathe in as well as out when they do so.

The investigators believe the experiments help to understand the physiological and social mechanism of how laughter is generated.

The group seems vital in unleashing the right kind of endorphin-making laughter, they contend.

Human evolution

“Laughter is very weird stuff, actually,” Dunbar said. “That’s why we got interested in it.”

And the study findings, published in the Proceedings of the Royal Society B: Biological Sciences, fit well with a growing sense that laughter contributes to group bonding and may have been important in the evolution of highly social humans.

Dunbar suggests that social laughter, relaxed and contagious, is “grooming at a distance”—an activity that fosters closeness in a group the way one-on-one grooming, patting and delousing promote and maintain bonds between individual primates of all sorts.

The study findings provided a partial answer to the ageless conundrum of whether we laugh because we feel giddy or feel giddy because we laugh, Dunbar said.

“The causal sequence is laughter triggers endorphin activation,” he said. What triggers laughter is a question that leads into a different labyrinth.

Dunbar thinks laughter may have been favored by evolution because it helped bring human groups together, the way other activities like dancing and singing do.

Those activities also produce endorphins, and physical activity is important in them as well, Dunbar said.

“Laughter is an early mechanism to bond social groups,” he said. “Primates use it.”

‘Pant, pant’

Indeed, apes are known to laugh, although in a different way than humans: They pant.

“Panting is the sound of rough-and-tumble play,” said Robert R. Provine, a neuroscientist at the University of Maryland, Baltimore County, and the author of “Laughter: A Scientific Investigation.”

It becomes a “ritualization” of the sound of play. And in the course of the evolution of human beings, Provine said, “pant, pant becomes ha, ha.”

Provine said he thought the study was “a significant contribution” to a field of study that dates back 2,000 years or so.

It has not always focused on the benefits of laughter. Both Plato and Aristotle, Provine said, were concerned with the power of laughter to undermine authority. And he noted that the ancients were very aware that laughter could accompany raping and pillaging as well as a comic tale told by the hearth.

Dunbar, however, was concerned with relaxed, contagious social laughter, not the tyrant’s cackle or the “polite titter” of awkward conversation.

He said a classic example would be the dinner at which everyone else speaks a different language and someone makes an apparently hilarious but incomprehensible comment.

Reports from AFP and New York Times News Service