Yawning is an everyday phenomenon perceived as a sign of drowsiness and boredom. Some people even see it as a sign of disrespect.
Robert R. Provine, the pioneer of yawning research, once wrote in 1986 that “Yawning may have the dubious distinction of being the least understood common human behavior.”
Today, yawning continues to be poorly understood, with no physiological significance associated with it.
Yawning is well known for its contagious effects. Besides humans, contagious yawning has been found in dogs and chimpanzees as well.
Past research by Ivan Norscia and Elisabetta Palagi demonstrated the correlation between strengthened social bond and yawning. Participants were more likely to yawn if they had a deeper social bond with the person yawning in the video.
Contagious yawning is a form of echophenomena, which is the automatic imitation of another person’s word or action without awareness.
Echophenomena is known to be associated with increased cortical motor excitability or decreased physiological inhibition. It is a symptom commonly found in disorders such as autism, epilepsy and Tourette syndrome.
According to a recent study published in Current Biology, Georgina Jackson, professor of cognitive neuropsychology at the University of Nottingham, and colleagues provided evidence for two findings. They found that instructions to resist yawning increases the urge to yawn significantly and causes more stifled yawns compared to full yawns.
The second finding was that cortical motor excitability and physiological inhibition are strongly associated with one’s inclination for contagious yawning.
The researchers took a sample of 36 neurologically healthy adults with an average age of 20. During the experiment, participants watched video clips of people yawning in four distinct blocks. They were either instructed to permit or resist their urges to yawn.
After the first two blocks, transcranial electrical stimulation (tES) was used on the supplementary motor area in conjunction to video clips. The supplementary motor area is the part of the brain responsible for planning complex movements.
In their results, the research team discovered that the number of stifled yawns increased after participants were told to resist yawning and the total number of yawns, including both full and stifled, were not significantly different between the first two blocks.
“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,” Jackson said, according to ScienceDaily.
Jackson and her team’s research serves as an example of how yawning, a widely misunderstood behavior, can provide insight to fixing other diseases.
“In Tourettes, if we could reduce the excitability, we might reduce the tics and that’s what we are working on,” Jackson said, according to ScienceDaily.
Tics play a significant role in shaping a Tourette syndrome patient’s experience. People with mild or severe tics can easily be viewed negatively by their peers or suffer from pain and discomfort from the repetitive movement. Reducing the tics improves the quality of life in individuals with Tourette syndrome.
In addition, the research team believes their findings can contribute to the development of non-drug treatments for neural diseases.
“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, personalized treatments,” Professor Stephen Jackson of University of Nottingham said, according to ScienceDaily.