September 05, 2017
Yawn and the world yawns with you, to misquote a familiar saying. But scientists say they may have discovered the reason why yawning can trigger the same response in someone near you.
Contagious yawning is a common form of echophenomena, the automatic imitation of another person's words or actions, according to scientists at the University of Nottingham.
They say it's something we share in common with chimpanzees and dogs.
Primitive Brain Function
Their findings suggest that primitive reflexes in the primary motor cortex may be behind the phenomenon. This is an area of the brain responsible for motor function and is linked to a network of brain regions that are associated with empathy and how we behave in social groups.
The scientists say that echophenomena is found in a wide range of conditions, including epilepsy, dementia, autism, and Tourette's syndrome, and that their findings may help us understand these disorders too.
The team monitored 36 adults to see what happened when they saw video clips of someone else yawning. The volunteers were instructed to either stifle yawning or to allow themselves to yawn.
Hard to Resist
Video evidence suggests demonstrated that our ability to resist yawning when someone else near us yawns is limited.
Also, our urge to yawn actually increases if we are instructed to resist yawning.
We may try to hold out against yawning, but we still feel the urge to do it, say the scientists.
They also found that our propensity for contagious yawning is individual to each one of us.
By using electrical stimulation known as transcranial magnetic stimulation (TMS), the team was able to boost 'excitability' in the motor cortex and increase a volunteer's urge to yawn.
Treating Other Conditions
The Nottingham scientists say they are looking for possible non-drug, personalised treatments, using TMS that might be effective in stabilising imbalances in brain activity.
One avenue is whether TMS could be used to reduce the involuntary and uncontrollable sounds and movements, known as tics, experienced by people with Tourette's syndrome.
The study is published in the journal Current Biology.