Why is yawning so contagious?

Yawning is so contagious that watching another person, dog or cat doing it, or even just reading about it, can trigger us to yawn.

Are you doing it yet?

It is one of the most common habits of humans, yet we still do not fully understand why we yawn. Previously, Dr Andrew Gallup, evolutionary psychologist at Princeton University said that “yawning is triggered by numerous eliciting stimuli, and thus we are still uncovering why we yawn in certain contexts and conditions.” 

Now, a new study from the University of Nottingham has shed light on why this occurs and why yawning is so contagious, and it is to do with the primitive part of the human brain. 

The researchers showed videos of people yawning to a group of participants and recorded their reactions. They also asked the participants to either yawn or resist yawning, and found when they told people they could not yawn their urge to yawn was increased.

Contagious yawning does not only happen to humans, we’ve seen it in dogs and chimpanzees too. It is a form of echophenomena – an automatic copying of someone else’s words or actions.

“This research has shown that the ‘urge’ is increased by trying to stop yourself,” said Georgina Jackson, professor of Cognitive Neuropsychology at Nottingham. “Using electrical stimulation we were able to increase excitability and in doing so increase the propensity for contagious yawning.”

The researchers used a technique called transcranial magnetic stimulation (TMS), where a magnet placed near the head can be used to stimulate different parts of the brain. This electrical stimulation in the primary motor cortex, the primitive part of the brain, also increased people’s urge to yawn.

The research could lead the way to helping people with other conditions that are linked to increased excitability in this part of the brain, like Tourette syndrome, epilepsy and dementia. “In Tourettes, if we could reduce the excitability we might reduce the ticks and that’s what we are working on,” said Jackson.

“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…such as epilepsy, dementia, autism, and Tourette syndrome,” said Stephen Jackson, Professor of Cognitive Neuroscience who led the study.

“If we can understand how alterations in cortical excitability give rise to neural disorders we can potentially reverse them,” he added. “We are looking for potential non-drug, personalised treatments, using TMS that might be affective in modulating inbalances in the brain networks.”