The researchers also found that the urge to yawn - our propensity for contagious yawning - is individual to each one of us. Contagious yawning is triggered involuntarily when we observe another person yawn. It is not just the humans who have a propensity for contagious yawning - chimpanzees and dogs do it too. To test the link between motor excitability and the neural basis for contagious yawning, the researchers used transcranial magnetic stimulation (TMS). "Using electrical stimulation we were able to increase excitability and in doing so increase the propensity for contagious yawning," said Jackson.

Source: dna September 02, 2017 10:07 UTC