Why is yawning contagious?

Why people yawn after seeing someone else yawn is one of those strange questions that no one really knows the answer to. It has been confirmed by many studies that 40-60% of people will yawn automatically after seeing another person yawn.

Originally it was thought that this was to do with the mirror neuron system, a system of the brain that enables us to imitate the actions of others. However a recent study conducted by Finnish scientists discovered that a contagious yawn is generally an unconscious urge to yawn, meaning it must bypass the mirror nueron system. The researchers found that the contagious yawn was actually part of the periamygdala section of the brain, which is the part that helps us interpret such things as facial expressions.

The scientist are still not entirely sure why the yawn is contagious, however they have busted the myth that it was an imitative act. Some people believe that it may have evolved from the early days of man as some type of signal that it was time to sleep. If one person yawned and then another yawned afterwards, it was seen as a sign that more than one person was tired and it was time for sleep.