When your friend stifles a yawn as you chat, don't be offended. Instead, take it as a compliment.
For, far from being a sign of boredom, yawning may signal empathy. Scientists believe that contagious yawning - yawning after someone else does - is a sign of being keenly interested in the first person's thoughts and feelings.
This is the theory of Italian researchers who observed more than 100 men and women from four continents as they went to work, ate in restaurants and sat in waiting rooms.
When one of the volunteers yawned, the researchers noted whether anyone within a 10ft radius 'caught' the yawn - that is, yawned within the next three minutes.
Their results showed that race and gender had no effect on whether the uncontrollable urge to yawn was passed on. But how well the two people knew each other did. A reciprocal yawn was most likely to occur among family members, then friends, then acquaintances. The phenomenon was least common among strangers, the journal PLoS ONE reports.
