Smile

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In physiology, a smile is a facial expression formed by flexing the muscles most notably near both ends of the mouth. The smile can be also around the eyes. Among humans, it's customarily an expression of pleasure, happiness, or amusement, but can also be an involuntary expression of anxiety, in which case it can be known as a grimace. There is much evidence that smiling is a normal reaction to certain stimuli and occurs regardless of culture. Happiness most often causes the smile to occur, though. Among animals, the exposure of teeth, which may bear a resemblance to a smile, are often used as a threat or warning display - known as a snarl - or a sign of submission. In chimpanzees, it can be a sign of fear.

Types of smiles

Researchers have identified two main varieties of smiles:

• The "Duchenne smile", after the researcher Guillaume Duchenne, is the most studied, and involves the movement of both the zygomaticus major muscle near the mouth and the orbicularis oculi muscle near the eyes. An example of the smile is shown in the girl's smile in the middle of the page. It is believed that the Duchenne smile is only produced as an involuntary response to genuine emotion, and is therefore what one could call the "genuine" smile. Due to the involvement of the muscle near the eyes, it is sometimes said that one can tell whether or not a smile is "real" by whether or not it "reaches the eyes".
• The "Pan American smile", on the other hand, is the voluntary smile involving only the zygomaticus major muscle to show politeness; for example, by a flight attendant on the former airline of the same name. Considered "insincere", this type of smile has also been called the "Professional Smile" by David Foster Wallace in his comedic short story "A Supposedly Fun Thing I'll Never Do Again".

References

• Miller, Professor George A., et. al. Overview for "smile." Retrieved 12 December 2003 from this page.

• Scanner shows unborn babies smile

See also

• Laughter
• Emotion
• Emoticon
• Facial Action Coding System
• Frown
• Facial expression
• Smiley
• Social Psychology

Images

Iraqi girl smiles.jpg Girl with closed mouth smile.

Girl with open mouth smile.

2005 03 01 rice blair 600.jpg Politicians and leaders are often shown smiling as this is considered a sign of confidence

Happy face ball.jpg Artwork on this ball is a common abstract representation of a smiling face.

External links

• See examples of genuine, false, and contempt smiles
• Spot The Fake Smile on BBC Science & Nature
• Have you smiled today? Let's smile together now! - Great positive!de:Lächelnfr:Sourire

he:חיוך id:Senyum it:Riso (ridere) ja:微笑み no:Smilsimple:Smile fi:Hymy sv:Leende vi:Cườiyi:שמייכל sv:Smile