Dec 29, 2011 2:00 PM by NBC News, (CC)
It's all in the family: you're more likely to yawn after you've seen a family member yawning, according to a recent study.
The fact that yawns are contagious has been well established -- although researchers still don't know the reasons behind it.
Researchers in Italy said you are more likely to yawn after seeing a family member yawn, compared to friends and strangers.
They say this suggests yawning may be a form of social empathy that illustrates the bond between two people.