Yawning is a suspicious and ubiquitous behaviour that has been reported in almost all vertebrates. Nevertheless, it is relatively understudied and its function and the underlying mechanisms have long been obscured. Recent studies suggest that yawning functions as a brain-cooling mechanism, through the enhancement of blood-flow to the brain, the refreshment of nasal air-pockets and the inhalation of cool air. It's contagion, however, remains a hotly debated topic, with hypotheses ranging from the synchronization of behaviour, collateral vigilance to (in my opinion prematurely) empathy.
In collaboration with Andrew Gallup, I study the proximate mechanisms underlying (contagious) yawning. And to also gain an evolutionary perspective, I use a comparative approach and study (contagious) yawning in a wide range of species ranging from chimpanzees, to marmosets, to humans.