Can babies read emotions?
A number of experiments have shown that if a parent looks towards something and displays fear, for example (by widening the eyes and stretching the mouth towards their ears) the child is very likely to become scared too, even if the baby cannot actually see what the parent is looking at.
This ability to experience fear when we see fear in others plays a vital role in our survival. It allows us to prepare for threats we may otherwise miss, and gives us a better chance of dealing with that threat. Whether that be through fighting or running away.
This behavior is not unique to humans, it can also be seen working throughout the animal kingdom.