Facial symmetry

Facial symmetry is one specific measure of bodily asymmetry. Along with traits such as averageness and youthfulness it influences judgments of aesthetic traits of physical attractiveness and beauty. For instance, in mate selection, people have been shown to have a preference for symmetry. This is because it is seen an indicator of health and genetic fitness, but also as holding adaptation qualities; reflecting the ability to withstand the changes in their environments.Original Facial symmetry is one specific measure of bodily asymmetry. Along with traits such as averageness and youthfulness it influences judgments of aesthetic traits of physical attractiveness and beauty. For instance, in mate selection, people have been shown to have a preference for symmetry. This is because it is seen an indicator of health and genetic fitness, but also as holding adaptation qualities; reflecting the ability to withstand the changes in their environments. Facial symmetry has been suggested as a possible physical manifestation of the 'big-five' personality traits. For example, it is found that extraversion and openness are strongly associated with the symmetry of the face. Hormones such as testosterone and estrogen are believed to be associated with developmental processes and growth of facial features during puberty and as a result are hypothesized to be the cause for individual differences in the implications associated with facial symmetry. Facial bilateral symmetry is measured via fluctuating asymmetry of the face comparing random differences in facial features of the two sides of the face that develop and accumulate throughout one's lifetime as a result of stressors. Facial symmetry has been shown to have an effect on ratings of attractiveness in human faces. More symmetrical faces are perceived as more attractive in both males and females, although facial symmetry plays a larger role in judgments of attractiveness concerning female faces. A wide variety of methods have been used to examine the claim that facial symmetry plays a role in judgments of beauty. Blending of multiple faces to create a composite and face-half mirroring have been among the techniques used. While studies employing the first method produced results that indicate that more symmetrical faces are perceived as more attractive, studies applying the later method have indicated that humans prefer slight asymmetry. Also studies show that nearly symmetrical faces are considered highly attractive compared to unsymmetrical ones, yet more specifically, people tend to find a face unattractive if a person has an unsymmetrical nose, and effect of unsymmetrical lips do not really affect people on judging attractiveness. The most conspicuous directional asymmetries are sometimes only temporary. For example, during speech, most people (76%) tend to express greater amplitude of movement on the right side of their mouth. This is most likely caused by the uneven strengths of contralateral neural connections between the left hemisphere of the brain (linguistic localization) and the right side of the face. Conclusions derived from face mirroring, however, have been called into question, because it has been shown that mirroring face-halves creates artificial features. For example, if the nose of an individual is slightly bent to the right side, then mirroring the right side of the face will lead to an over-sized nose, while mirroring the left side will lead to an unnaturally small nose. Evolutionary theorists in biology and psychology argue that more symmetric faces are preferred because symmetry is a possible honest sign of superior genetic quality and developmental stability. However it is possible that high facial symmetry in an individual is not due to their superior genetics but due to a lack of exposure to stressors during development. This potentially confounding source of facial symmetry is not explored in the literature. The notion that facial symmetry is viewed by humans as an indicator of 'good genes' is supported by experiments demonstrating that more symmetrical faces are rated as healthier than less symmetrical faces. For example, evidence has found that ratings of a person’s facial symmetry is positively associated with ratings of healthiness of their facial skin. Additionally, asymmetry can be fluctuated by increasing health challenges during growth. As a result, phenotypic quality and how well an individual's genome can fight disease and uphold normal development can be indicated by symmetry. Furthermore, studies suggest that facial fluctuation asymmetry, non symmetrical faces, may also be associated with an individuals physiological, psychological and emotional distress. Additionally current studies indicate that face preferences in adults can be predicted by the number of infections in childhood. People who had more infections as children prefer more sex-typical and symmetric faces because those faces indicate being healthy. Especially recent infections trigger this preference.