User:EricT223/sandbox

A smile is formed primarily by flexing the muscles at the sides of the mouth. Some smiles include a contraction of the muscles at the corner of the eyes, an action known as a Duchenne smile. Among humans, a smile expresses pleasure, sociability, happiness, joy 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, there are large differences among different cultures, religions and societies, with some using smiles to convey confusion or embarrassment. '''A study done by the Association for Psychological Science indicates that the act of smiling may positively affect our physical state by lowering our heart rates and aiding in the recovery from stressful situations.  Similarly, another study done by Swedish scientists at the University of Uppsala, determined that when a human sees a face smiling back at them, their response is commonly a positive emotional stimulus, or a smile back. '''