People often laugh when others laugh, smile when others smile, and frown when others frown. According to livescience.com, the same thing is true for yawning.

The average yawn lasts about six seconds. Yawning may be caused by stress, exhaustion, tiredness, and boredom. Scientists even theorize that we yawn to stretch our lung muscles.

Yawning is directly linked to our ability to connect with others emotionally. How empathetic you are towards others may actually be part of the cause of contagious yawning. It is theorized that people yawn with others as a way to emotionally connect, and yawning has to do with social attachment between individuals.

Recent studies show that it may even be linked to the cooling of the brain, which helps keep your body and mind awake and functioning, as your body temperatures go up when you sleep. Increasing oxygen in your brain helps ready you for action.

Reading about, hearing, or even just thinking about a yawn can make you do it. But yawning is not just contagious between humans, it is even contagious between animals. Studies have suggested that infectious yawning developed to keep animal groups alert. Other studies show that dogs yawn more when they see people they know do so as opposed to a stranger yawning.

People with autism are less likely to catch a yawn; the more severe the condition of the autistic person, the less common the behavior gets. Yawns become contagious around age four, and its contagion is usually unconscious. When we see a yawn, we usually yawn. But when we do, then we do so unconsciously until we realize that we really are yawning. Contagious yawning is a complete phenomenon.

Try it! If you have a pet, yawn in front of it and see what happens. You could also watch strangers yawn and see if they cause you to want to yawn as much as your friends and family do when they yawn. There’s even the option of writing “yawn” over and over and over again and seeing how many times you yawn in the time it takes you to type “yawn yawn” and fill a page with yawn!

Yawning is important because it gets colder air to your brain, as it heats up when it’s tired. This may be the reason why we are more awake in winter than in summer. It is so cool that there is a way to stay awake without caffeine.