Mar 25, 2010
* A smile is a facial expression formed by flexing those muscles most notably near both ends of the mouth.
* Among humans, it is customarily an expression denoting pleasure, happiness, or amusement, but can also be an involuntary expression of anxiety, in which case it is known as a grimace.
* Cross-cultural studies have shown that smiling is used as a means of communicating emotions throughout the world.
Happiness is most often the motivating 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 also be a sign of fear.
* Laughter is an audible expression or the appearance of happiness, or an inward feeling of joy (laughing on the inside). It may ensue (as a physiological reaction) from jokes, tickling or other stimuli. It is in most cases a very pleasant sensation.
Bejegyezte: Csernaczki Emoke