It's now official: Yawns are really contagious when they come from family members or close friends, a new study says.
The reason why people can't resist without yawning when they see others doing so has long perplexed scientists. Some have suggested the behaviour was a form of social empathy which helps people to connect with one another.
Now, a new study by a team from the University of Pisa in Italy has shown that the biggest factor in whether or not a yawn is contagious is the relationship between the yawner and the person who hears or sees it, the Daily Telegraph reported.
People are most likely to "catch or pass on" a yawn when interacting with family members, followed on a decreasing scale by friends, then acquaintances and lastly strangers - the same pattern that is seen for other measures of empathy, the researchers found. The findings were published in the Public Library of Science ONE journal.