The Science of Smiles
Charles Darwin observed that smiling is a universal expression, whereas other body language cues and gestures vary from culture to culture. Even smiling can vary from one culture to another. For example, people in the southern United States are more likely to smile than people in the northern United States. Eastern Asians often cover their mouths when they smile and British people tend to smile pursed instead of upward, keeping a stiff upper lip.
In fact, we often say “cheese” for a photograph because saying cheese forces your face into a sort of smile.
Smiling is an important part of social interaction. In ...