PISA - This story is a yawner.

You’ve been there before: standing in line or sitting around the conference table when some sleepy-eyed dude lets loose a big ol’ yawn, and you  – tired or not – start yawning too. 

Yes, yawns are indeed contagious. Research has shown that some 50 percent of humans who watch a video of someone yawning will quickly yawn in response. Sometimes just reading about it can set one off too. Did someone say: yaaaawn....??

If daddy sees, you know what he'll do... (Dangermain)

Now a new Italian study digs deeper to find out just how contagious one yawn is from another, reports La Stampa.

Elisabetta Palagi, a zoologist at the University of Pisa’s natural history museum, notes that the causes of yawning are still not entirely clear, but that a yawn has developed a “social function,” and that people yawn more when they are in a group than by themselves.

The yawn, which is present in countless species, is only contagious amongst those with more advanced intelligence, where it has evolved into a mode of communication. More specifically, the follow-up yawn is an expression of empathy, Palagi says.

Tracking the yawning habits of both humans and Bonobo chimpanzees, Palagi’s team has concluded that the closer the relation to the yawner, the more likely that yawn will be contagious.

Ever see a swamp monkey yawn? (Lazarite)

“The only important parameter of contagiousness is the type of relation that links the two subjects,” Palagi told La Stampa. “Nationality, gender, context are not important, only the quality of the link that unites the emitter and receiver (of the yawn).”

Thus yawns from close relatives are more likely to prompt empathetic yawns than from recent friends, and certainly from strangers, the study concludes.

An interesting finding in the study of the Bonobos is that the female chimpanzee species is more likely to let loose a yawn of empathy than the male counterparts. Initial conclusions on this front for humans are the same – women are more likely to yawn empathatically than men.

Needless to say, that conclusion is likely to provoke a different kind of yawn from some male readers.