S u m m a r y :
The more you resist yawning, the more you feel like yawning! New findings shedding further light on the contagious action might be used to design individualised treatment procedures for patients of neural disorders like dementia. The paper is published in the journal Current Biology.
All About Yawning
The urge for contagious yawning is automatically stimulated by reflexes found in the motor cortex, the brain area responsible for motor function, the latter term englobing the processes by which we use our brain to coordinate movement in muscles. Furthermore, while we can resist the propensity to yawn, the ability itself remains limited: no matter how much we can try to stifle a yawn, our tendency to do so remains unchanged. Quite surprisingly, the urge to yawn increases when we are told to resist it. This propensity is, however, different for every one of us.
The authors of the research believe that their findings will help them understand the link between the excitability of the motor cortex and the occurrence of echophenomena in certain disorders.
Yawning & Echophenomena
Yawning is contagious—we cannot help but yawn when we see someone else yawning; even dogs and chimps have such a tendency. Moreover, even the mere mention of the action is sometimes enough to trigger the same in ourselves. In the world of science, we call this involuntary, reflexive imitation of other’s (their words or actions) as echophenomena.
As a matter of fact, echophenomena extends to certain disorders—like Tourette syndrome, dementia, epilepsy, and autism—characterised by increased excitability of the cerebral cortex and/or decreased physiological inhibition. What remains a mystery is the cause behind this phenomenon.
Resisting & Succumbing to Yawning
Using transcranial magnetic stimulation (TMS), a team of researchers from Nottingham University attempted to determine the link between motor excitability and contagious yawning.
The volunteers were made to view video clips depicting an individual yawning: a group of them were to let themselves yawn, and another was to resist the contagious action. Their number of yawns and stifled yawns were recorded together with the intensity of their perceived urge to yawn. Also, the participants’ urge to yawn was increased through electrical stimulation.
Resist Yawning, and Yawn Some More!
The findings show that the more you resist yawning, the more you feel like yawning! Study author Georgina Jackson explains that the urge is increased when one tries to stop oneself from yawning. Given that they have electrically enhanced the tendency to yawn, Jackson and her colleagues believe that they might ultimately be able to understand and tackle certain disorders.
“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,” says Jackson.
Individual Yawning Experience
Interestingly, TMS could be used to predict the propensity of each individual participant for contagious yawning. Not only did the TMS measures turn out to be significant predictors of contagious yawning but they also showed that the urge to yawn is determined by cortical excitability and physiological inhibition of the primary motor cortext. Furthermore, the urge to yawn is difference for every one of us.
Co-author Stephen Jackson comments that neural disorders might potentially be reversed if we can understand how they are caused by modifications in cortical excitability. Their aim is to build non-drug and personalised treatments.