One of the most useful ways to categorize smiles is according to their social function, or the purposes they serve in groups of people.
Broadly sp… See more

Many smiles arise from a positive feeling — contentment, approval, or even happiness in the midst of sorrow. Researchers describe these as “reward” smiles because we use the… See more

People also use smiles to reassure others, to be polite, and to communicate trustworthiness, belonging, and good intentions. Smiles like these have been characteriz… See more

People sometimes smile to show their superiority, to communicate contempt or derision, and to make others feel less powerful. You might call it a sneer. The mechanics … See more