A frown (also known as a scowl) is a facial expression in which the eyebrows are brought together, and the forehead is wrinkled, usually indicating displeasure, sadness or worry, or less often confusion or concentration. The appearance of a frown varies by culture. Although most technical definitions define it as a wrinkling of the brow, in North America it is primarily thought of as an expression of the mouth. In those cases when used iconically, as with an emoticon, it is entirely presented by the curve of the lips forming a down-open curve. The mouth expression is also commonly referred to in the colloquial English phrase "turn that frown upside down" which indicates changing from sad to happy.
Charles Darwin described the primary act of frowning as the furrowing of the brow which leads to a rise in the upper lip and a down-turning of the corners of the mouth. While the appearance of a frown varies from culture to culture, there appears to be some degree of universality to the recognition of the frown as a negative facial expression. In fact, frowning as a component of anger or disgust is widely recognized as a universal expression easily recognized across cultures. This universality suggests a shared adaptive quality to frowning allowing for social communication of negative emotional states.
Scott Fahlman first suggested the use of the colon with the left parenthesis to iconically represent a frowning face on the Internet in what has become a well-known emoticon. In this form the frown is entirely presented as a curve of the lips facing away from the eyes. Specifically, frowns that incorporate the furrowing of the brow are a response to perceived obstacles to the achievement of goals, while frowns that involve movement of the cheeks reflect an unpleasant reaction. Just as smiling alone can make one feel better, frowning can make one feel worse. In a scientific study participants that held their face in a frown ranked images as more unpleasant than participants who viewed the images with a neutral facial expression. In a similar test, participants reported increased anger with the manipulated expression of a frown and they also ranked cartoons they saw as less funny than participants with the manipulated expression of a smile.