A yawn is an involuntary action characterized by opening the mouth, breathing in, expanding a tube that leads to the eardrums, and then exhaling. The whole process takes about six seconds, and may be one of the best known social contagions
you just yawned when she yawned! did you know that scientists connect contagious yawning to empathy, sensing other people’s emotions and imagining what they might be thinking or feeling
children are 4 or 5 years old, about the same time children develop the ability to identify other people’s emotions. It decreases along with empathetic abilities in old age.