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 - known as a snarl - or a sign of submission. In chimpanzees, it can be a sign of fear. This article or section does not cite any references or sources. ... Photographs from the 1862 book Mécanisme de la Physionomie Humaine by Guillaume Duchenne. ... A top-down view of skeletal muscle Muscle (from Latin musculus little mouse [1]) is contractile tissue of the body and is derived from the mesodermal layer of embryonic germ cells. ... It has been suggested that this article or section be merged with mouth (human). ... Trinomial name Homo sapiens sapiens Linnaeus, 1758 Humans, or human beings, are bipedal primates belonging to the mammalian species Homo sapiens (Latin: wise man or knowing man) in the family Hominidae (the great apes). ... In the sense used in philosophy and the social sciences, a convention is commonly seen as a set of widely agreed or accepted rules or customs. ... Look up Pleasure in Wiktionary, the free dictionary. ... Amusement, Viktor Vasnetsov Amusement is the state of experiencing humorous and usually entertaining events or situations, and is associated with enjoyment, happiness, laughter and pleasure. ... This article includes a list of works cited or a list of external links, but its sources remain unclear because it lacks in-text citations. ... Grimace Grimace is part of the marketing campaign of McDonalds. ... “Animalia” redirects here. ... Types of teeth Molars are used for grinding up foods Carnassials are used for slicing food. ... A threat is a declaration of intention to inflict punishment or harm on another. ... A man snarling A snarl is a facial expression, where the upper lip is raised, and the nostrils widen. ... Submission can refer to: An object to hand in A proposal for a presentation at an academic conference Domination and submission, where it is opposite in meaning to dominance. ... Species Pan troglodytes Pan paniscus Chimpanzees, also called chimps, are the common name for two species in the genus Pan. ... Fear is a powerful biological feeling of unpleasant risk or danger, either real or imagined. ...

Images

A ball with a smiley face. Image File history File linksMetadata Size of this preview: 800 × 568 pixel Image in higher resolution (2048 × 1455 pixel, file size: 1. ... Balls are objects typically used in games. ...

A natural smile with teeth showing. Image File history File links Download high-resolution version (1024x683, 300 KB) File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Smile Talk:Jim Hoffman ...

A smiling Iraqi girl. Download high resolution version (2048x1536, 1239 KB) Wikipedia does not have an article with this exact name. ...

A girl smiling. Image File history File linksMetadata Size of this preview: 450 × 600 pixel Image in higher resolution (1944 × 2592 pixel, file size: 1. ...

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".

Guillaume Benjamin Amand Duchenne was a French neurologist born in Boulogne on September 17, 1806. ... The Zygomatic major is a muscle of the human body. ... The Orbicularis oculi is a muscle of the human body. ... The Zygomatic major is a muscle of the human body. ... Politeness is best expressed as the practical application of good manners or etiquette. ... Flight attendant in an Embraer ERJ 145 LR (PBair, Thailand) Stewardess, circa 1949-50, American Overseas, Flagship Denmark, Boeing Stratocruiser In aviation, flight attendants—also known as sky girls, air hostesses, stewardesses or stewards—are members of a flight crew employed by airlines to ensure the safety of the passengers... Pan American World Airways, commonly known as Pan Am, was the principal international airline of the United States from the 1930s until its collapse in 1991. ... David Foster Wallace is an American novelist, essayist, and short story writer. ... A Supposedly Fun Thing Ill Never Do Again is the title essay of a collection of non-fiction writing by David Foster Wallace. ...

References

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

• Scanner shows unborn babies smile

December 12 is the 346th day (347th in leap years) of the year in the Gregorian calendar, with 19 days remaining. ... 2003 (MMIII) was a common year starting on Wednesday of the Gregorian calendar. ...

See also

• Emotion
• Emoticon
• Facial Action Coding System
• Scowl
• Facial expression
• Smiley
• Social Psychology

For other uses, see Emotion (disambiguation). ... An emoticon (pronounced (IPA) ) is a small piece of specialized ASCII art (usually two to five characters, always on a single line) used in text messages as informal markup to indicate emotions and attitudes that would be conveyed by body language in face-to-face communications. ... Facial Action Coding System (FACS) is a system originally developed by Paul Ekman and Wallace Friesen in 1976, to taxonomize every conceivable human facial expression. ... A man is frowning in this painting by Albrecht Dürer. ... Photographs from the 1862 book Mécanisme de la Physionomie Humaine by Guillaume Duchenne. ... The smiley has gone through many incarnations over the years, but it consistently retains the same features. ... The scope of social psychological research. ...

External links

Wikimedia Commons has media related to:

Smile

• See examples of genuine, false, and contempt smiles
• Spot The Fake Smile on BBC Science & Nature