Humans Can't Not Smile
It's difficult for humans not to smile when they see someone else smiling, and that's because of "mirror neurons".
from Stuff to Blow Your Mind
Key Facts In This Video
Because of "mirror neurons" and social norms, humans tend to smile when we see others doing it. (0:12)
One study found those who smile more often appeared more competent in the eyes of their peers. (1:52)
Smiling can reduce blood pressure, release endorphins and can create an overall improved mood. (2:06)