Contagious yawning is triggered involuntarily when we observe another person yawn.
But our ability to resist when someone near us starts yawning is limited, and our urge to yawn actually increases if we are instructed to resist yawning.
However no matter how hard we try to stop, it might change how we yawn – but it won’t alter our propensity to yawn.
Nottingham University researchers explained the contagious yawn was triggered automatically by primitive reflexes in the primary motor cortex, the area of the brain responsible for motor function.
It is a common form of echophenomena, which is the automatic imitation of someone else’s words, known as echolalia, or actions called echopraxia.
The researchers also found it is not just in humans involuntary yawning occurs as the behaviour has been seen in chimpanzees and dogs.
The study, published in the journal Current Biology, is part of broader research into the underlying biology of neuropsychiatric disorders and the search for new methods of treatment.
Professor Stephen Jackson, said: “We suggest that these findings may be particularly important in understanding further the association between motor excitability and the occurrence of echophenomena in a wide range of clinical conditions that have been linked to increased cortical excitability and/or decreased physiological inhibition such as epilepsy, dementia, autism, and Tourette syndrome.”
For their research the team looked into the link between motor excitability and the neural basis for contagious yawning and used a transcranial magnetic stimulation (TMS).
They recruited 36 adults to help with their study, who viewed video clips showing someone else yawning and were instructed to either resist yawning or to allow themselves to yawn.
The participants were videoed throughout, and their yawns and stifled yawns were counted.
In addition, the intensity of each participant’s perceived urge to yawn was continuously recorded.
Scientists also found using electrical stimulation they were also able to increase the urge to yawn.
Professor Georgina Jackson form the Institute of Mental Health, said: “This research has shown that the ‘urge’ is increased by trying to stop yourself.
“Using electrical stimulation we were able to increase excitability and in doing so increase the propensity for contagious yawning.
“In Tourettes if we could reduce the excitability we might reduce the ticks and that’s what we are working on.”
The TMS results were able to predict contagious yawning and showed each individual’s propensity for contagious yawning is determined by cortical excitability and physiological inhibition of the primary motor cortext.
Professor Jackson added: “If we can understand how alterations in cortical excitability give rise to neural disorders we can potentially reverse them.
“We are looking for potential non-drug, personalised treatments, using TMS that might be affective in modulating inbalances in the brain networks.