Laughter really is the best medicine. Researchers at the University of Oxford have shown that uncontrollable, social laughter is associated with an improved pain threshold.
Credit: Veer
SYDNEY: Authentic, uncontrollable laughter may encourage positive affects and improve our ability to cope with pain, a new study suggests.
Researchers at the University of Oxford in England have shown that social laughter is related to an increased pain tolerance, which is likely due to 'painkilling' endorphins released in the process.
The findings, published last week in Proceedings of the Royal Society B, showed that the pain thresholds of a group of subjects had increased by an average of 10% after watching 15 minutes of comedy clips.
"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," said lead author Robin Dunbar, an evolutionary psychologist at the University of Oxford.
Endorphin explanation
Years of study on endorphins, the peptides that act as neurotransmitters in our body, have revealed their ability to promote feelings of 'well-being' and defend our bodies against mental and physical stress.
The researchers hypothesised that laughter stimulates the release of these precious endorphins in a similar way that physical exercise does.
When humans laugh deeply, we endure a series of continuous exhalations without drawing any breath, leading to that well-known sensation of pure elation and painful, keeled-over suffocation.
It is this exhausting abdominal workout, or possibly the physical toll of emptying the lungs, that the researchers suggest triggers the endorphin activity in humans and leads to feelings of positive well-being and pain relief.
Contagious laughter works best
But the researchers also make a careful distinction between feigned, forced and solitary laughter and Duchenne laughter, also known as social laughter.
Duchenne laughter is contagious and involves "involuntary contraction of the orbicularis oculi muscles - those tiny areas at the sides of the eye that crease when you experience a deep-felt, hearty laugh. Duchenne laughter is alone thought to allow the capacity for endorphin release.
The researchers executed six experiments in the study, in which they played comedic film clips from the TV shows Friends and Mr. Bean, as well as live stage shows and clips of shows intended to provoke a neutral response. They then measured subjects' pain thresholds before and after viewing.
They tested subjects alone and in groups, and found that those who had watched comedic material with a group of people and experienced Duchenne laughter had the greatest increase in pain threshold.
This was assayed by testing subjects' capacity to endure the sting of freezing cold sleeves, the physical force of a blood pressure cuff and the strain of endurance-testing thigh workouts.
Regulating endorphins
Macdonald Christie, a pharmacologist at the University of Sydney, agreed that the researchers proved there was a correlation between pain threshold and laughter, but thought the study fell short in proving this was due to endorphins.
A foolproof way to test for endorphin activity would be to inject the subjects with a drug that blocks the opiate receptor, which is directly involved in regulating endorphin levels, commented Christie.
If they had blocked endorphin activity in a group of subjects after the first pain test, but before watching the comedy show, the researchers could have determined whether a change in pain threshold was indeed directly caused by endorphin activity, added Christie.
Laughter's social evolution
We share the capabilities for laughter with the great apes, suggesting it is a primitive trait. However, apes both inhale and exhale while laughing, whereas humans typically endure a series of continuous exhalations without drawing any breath, which is a crucial component of the capacity for language.
The researchers maintain that the release of endorphins after laughing may have evolved to promote Duchenne laughter and further social behaviour among humans.
"We think that it is the bonding effects of the endorphin rush that explain why laughter plays such an important role in our social lives," said Dunbar.
The researchers recognise further possible studies in which other positive effects of laughter could be explored, such as enhanced 'prosociality' and altruistic behaviour.
