Most people have experienced it. A person yawns and then a few minutes later, another person nearby yawns. Is it always fatigue? Do tired people just happen to gather together? Not exactly. Yawning has always been seen as somewhat "contagious" because once it starts, others around them tend to follow.
New research shows that it's an automatic reaction from one part of the brain. A study conducted by neuroscientists at the University of Nottingham looked at the primary motor cortex and found that the yawns that are triggered by seeing others yawn are likely a reflex action. The study is published in the journal Current Biology. It's part of a group of research projects that are looking to the brain for the biology beneath several neuropsychiatric disorders. Knowing more about the mechanical underpinnings of these disorders can help find more suitable treatments.
Echophenomena, which occurs in humans as well as some animals, is the natural reaction to copy what happens around us. Echolalia is how babies learn to speak; they naturally imitate the vocalizations that they hear around them. Echopraxia, the imitation of another's actions, is involved in how babies learn to pick up toys, crawl or walk. Yawning is part of this, and apparently, it can't be helped. A yawn might be minimized or controlled, so it's not a gaping roar of embarrassment, but when someone near us yawns, we are going to want to yawn as well. It's a natural and unpreventable reflex action.
Stephen Jackson, Professor of Cognitive Neuroscience, at University of Nottingham's School of Psychology, led the project and explained, "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."
So how did the researchers in Jackson's group test this? They used transcranial magnetic stimulation (TMS). Thirty-six study volunteers were asked to view clips of people yawning. They were instructed to either resist yawning or to allow themselves to yawn. Video of the participants' reactions to the yawning clips was taken and analyzed to see how intense the urge to yawn was. It varied between individuals. The TMS stimulation was also part of the experiments since researchers were able to use it to increase the urge to yawn in those volunteers who had a lower response to contagious yawning.
The TMS was also able to gauge the excitability of the neurons in the primary motor cortex. Georgina Jackson, Professor of Cognitive Neuropsychology at the Institute of Mental Health at Nottingham, explained that the ability of the team to manipulate the excitability factor could mean that treatments for diseases like Tourette's could come about from this work. She stated, "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 Tourette's if we could reduce the excitability we might reduce the ticks, and that's what we are working on."
The video below explains more about the work and what it could mean for a host of neuropsychological disorders that are related to the primary motor cortex and the excitability of the neural networks it contains. Check it out.
Sources: University of Nottingham via Eureka, Current Biology, BBC