Smile

For other uses, see Smile (disambiguation).

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A laughing smile with teeth showing and mouth open.

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 is 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 is most often the cause of a smile. Among animals, the exposure of teeth, which may bear a resemblance to a smile, is 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.

The Philosopher Democritus, by Agostino Caracci

Contents 1 Types of smiles 2 Historical background 3 References 4 See also 5 Images 6 External links

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".

The Laughing Cavalier, by Frans Hals, 1624: the "laugh" is only in the eyes

Historical background

Many biologists think the smile started as a sign of fear. Primalogist Signe Preuschoft traces the smile back over 30 million years of evolution to the "fear grin." Monkeys and apes used barely clenched teeth to portray to predators that they were harmless. Biologists believe the smile has evolved differently among species and especially among humans.

Biology is not the only academic discipline that interprets the smile. Those who study kinesics view the smile as an affect display. It can communicate feelings such as: love, happiness, pride, contempt, and embarrassment.

References

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

• Conniff, R. (2007). What\'s behind a smile? Smithsonian Magazine, 38,46-53.

• Ottenheimer, H.J. (2006). The anthropology of language: An introduction to linguistic anthropology. Belmont, CA: Thomson Wadsworh.

• Scanner shows unborn babies smile

See also

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

Images

Wikimedia Commons has media related to:

Smile

Iraqi girl smiles.jpg Girl with closed mouth smile.

Asian girl with dimples.jpg 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
• Expressions of Positive Emotion in Women\'s College Yearbook Pictures and Their Relationship to Personality and Life Outcomes Across Adulthood.

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