It is common knowledge that yawning is contagious, but not many are aware of why it is so.
A 2025 article in Psychology Today defined contagious yawning as “the tendency of individuals to yawn after seeing, hearing, or even thinking about someone else yawning.”
The behaviour is not limited to humans alone, but has also been observed in other animals such as domesticated dogs, chimpanzees, bonobos, macaques, gelada baboons, and even parrots. Yawning itself is an involuntary reflex action that scientists are still studying the cause of. When it comes to contagious yawning, the exact cause is being debated as well. However, there are two leading hypotheses on the issue. They are explained as follows. It supported the idea that such behaviours may promote social cohesion. There is research that supports this idea as well. Studies have shown that domesticated dogs yawn more frequently when they observe their owners yawning than when they observe strangers. Similarly, chimpanzees and bonobos tend to yawn more frequently when observing familiar individuals, indicating that emotional closeness influences contagious yawning.
Studies have shown that about 40 to 60 percent of people exhibit contagious yawning when exposed to these triggers. The hypothesis is supported by a 2011 study , where researchers studied parrots and found the birds demonstrated yawning and stretching behaviours in synchrony.
