ROME- If you let out a great yawn and the person next to you follows suit, they must really like you.
This is the conclusion of a scientific study that suggests that contagious yawns are a sign of deep empathy.
Research published yesterday suggests that the ‘catching yawn’ is caused by an irrepressible need to share and understand the emotions and feelings of others.
The ‘emotional bridge’ created by the shared experience enhances social bonding, according to Italian scientists.
The researchers, who monitored 33 adults over 380 hours, found that a yawn was far more likely to spread among groups of friends.
The scientists, from universities in Pisa, Parma and Rome, also tracked the way yawns spread among bonobos, a species of chimpanzee closest related to humans.
They monitored the apes for 800 hours, and found that a yawn ‘wave’ was just as likely to spread among the bonobos as it was in humans.
The impact of friendship, however, was not evident among the chimpanzees.
A yawn was just as likely to spread between unrelated primates as it was between family members or those of the same kinship groups.
The researchers concluded that the human ability to feel empathy is far stronger between friends and relatives.
They wrote in the journal PeerJ: ‘Compared to bonobos, the human susceptibility and promptness to others’ yawns were significantly more potentiated when kin and friends were involved.
‘Humans’ responses were more frequent and faster when the trigger and responder shared a strong emotional bond.
‘On the other hand, susceptibility and promptness incredibly overlapped between the two species when a strong emotional involvement was lacking, thus indicating that emotional contagion is not always highest in humans.’
They added: ‘Humans show a different degree of sensitivity… but only when they are strongly emotionally involved.’
Biologists believe contagious yawns are caused by an involuntary re-enactment of the facial expression seen in others.
They think ‘mirror neurons’ in the pre-frontal cortex – the brain region involved in social behaviour – fire when certain expressions are seen in other people, prompting us to instinctively copy them.
The new research suggests that this ‘mirror system’ is strongest between people who are emotionally attached, probably by shared memories.
The Italian scientists think that the difference between humans and bonobo apes is most profound when it comes to the strongest of our social bonds, particularly those shared with friends and family members.
When it comes to strangers, however, the results suggest we possess no more empathy than the apes.