Laughing with your friends releases endorphins in your brain, and the more opioid receptors you have, the more you tend to laugh, according to a new study by researchers at the University of Turku and Aalto University in Finland and the University of Oxford in England.
The findings, recently published in The Journal of Neuroscience, also show how social laughter helps promote the establishment of social bonds.
For the study, participants were injected with a radioactive compound binding to their brain’s opioid receptors while they underwent positron emission tomography (PET).
Scans were used to measure the “endorphin rush” in 12 healthy men after their opioid systems had been stimulated by watching 30 minutes of comedy clips together. Radioactivity in the brain was measured twice with the PET camera: once after the participants had laughed together with their friends, and again after they had spent comparable time alone in the laboratory.
During the study, the researchers found that social laughter led to pleasurable feelings and significantly increased the release of endorphins and other opioid peptides in brain areas associated with arousal and emotions. The more opioid receptors the participants had in their brain, the more they laughed during the experiment.
In another experiment, the pain threshold caused by the endorphin rush was much higher in both male and female volunteers when they watched comedy rather than drama in groups.
“Our results highlight that endorphin release induced by social laughter may be an important pathway that supports formation, reinforcement, and maintenance of social bonds between humans,” said Professor Lauri Nummenmaa from the Turku PET Centre at the University of Turku.
“The pleasurable and calming effects of the endorphin release might signal safety and promote feelings of togetherness. The relationship between opioid receptor density and laughter rate also suggests that opioid system may underlie individual differences in sociability.”
The study findings emphasize the importance of vocal communication in maintaining human social networks. Other primates maintain social contacts through the endorphin-releasing act of mutual grooming, which of course, isn’t very applicable in our society.
But since social laughter leads to a similar chemical response in the brain, it may allow for the significant expansion of human social networks. For example, laughter is highly contagious, and the endorphin response may thus easily spread through large groups that laugh together, said Professor Robin Dunbar of the University of Oxford.
Source: University of Turku