(USATODAY) — Warning: This story may make you yawn. That’s because yawning is so highly contagious that even reading about it, much less seeing or hearing someone yawn, is enough to get many people going.

Why? Contrary to popular theory and a number of studies, it may not be all about empathy – the capacity to share the emotions and experiences of others, a new study suggests.

“Empathy does play a role, but it’s just not the huge role people were thinking,” says study author Elizabeth Cirulli, an assistant professor of medicine at Duke University School of Medicine. The study, among the biggest ever to examine this little quirk, was published online Friday by PLOS ONE.

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