India, May 2 -- Yawning is an involuntary reflex action that is widely considered to be a sign of fatigue, boredom, or stress. However, a study published in the Respiratory Physiology & Neurobiology, titled Biomechanics of contagious yawning: Insights into cranio-cervical fluid dynamics and kinematic consistency, has revealed something unexpected about the effect of yawning on the flow of fluid that protects the brain.

While scientists are not clear about the impact of the findings, researchers from the University of New South Wales in Australia believe that the discovery can provide clues as to why humans and other animals evolved the capacity to yawn in the first place.

There were 22 healthy participants in the study, who were asked t...