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A Nepali Newar woman smiling

A smile is a facial expression formed primarily by flexing the muscles at the sides of the mouth.<ref>{{#invoke:citation/CS1|citation |CitationClass=book }}</ref> Some smiles include a contraction of the muscles at the corner of the eyes, an action known as a "Duchenne smile". Smiles performed without the eye contraction can be perceived as "fake".

Among humans, smiling is an expression denoting pleasure, sociability, happiness, or amusement. It is distinct from a similar but usually involuntary expression of anxiety known as a grimace. Although cross-cultural studies have shown that smiling is a means of communication throughout the world,<ref>{{#invoke:citation/CS1|citation |CitationClass=book }}</ref> there are large differences between different cultures, with some using smiles to convey confusion or embarrassment.

Smile sections
Intro   Historical background    Social effects    Cultural differences    Dimples    Duchenne smile    In animals    See also    References    Further reading    External links   

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