Progressive changes occurring throughout life in the soft tissues of the face will cause more prominent facial asymmetry in older faces. Therefore, symmetrical transformation of older faces generally increases their attractiveness while symmetrical transformation in young adults and children will decrease their attractiveness. Personality and Big Five personality traits
Research indicates that facial symmetry is correlated with the big-five model of personality. The five factors are:
Openness to experience (inventive/curious vs. consistent/cautious)
Conscientiousness (efficient/organized vs. easy-going/careless)
Extraversion (outgoing/energetic vs. solitary/reserved)
Agreeableness (friendly/compassionate vs. challenging/detached)
Neuroticism (sensitive/nervous vs. secure/confident)A consistent finding is that facial symmetry is positively correlated with extraversion, indicating that individuals with more symmetric faces are also more extroverted. More symmetrical faces are also judged to be lower on neuroticism but higher on conscientiousness and agreeableness (asymmetrical faces were rated as less agreeable than normal ones, but the more symmetrical were again rated as somewhat less agreeable than the normal). More symmetrical faces are also more likely to have more desirable social attributes assigned to them, such as sociable, intelligent or lively.However, the relationship of facial symmetry and the big-five personality model remains somewhat unclear with regard to neuroticism, openness, agreeableness and conscientiousness. Openness and agreeableness appear to be significantly negatively related to facial symmetry, while neuroticism and conscientiousness do not seem to be linked to facial symmetry. With respect to trustworthiness it has been found that the facial muscles become imbalanced when lying. Evolution and sexual selection
Sexual selection is a theoretical construct within evolution theory. According to sexual selection, mate choice can have profound influence on the preferred features.
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. Attractiveness
Facial symmetry has been found to increase 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.While studies employing the composite faces produced results that indicate that more symmetrical faces are perceived as more attractive, studies applying the face-half mirroring technique have indicated that humans prefer slight asymmetry. Also, studies have shown that nearly symmetrical faces are considered highly attractive as compared to asymmetrical ones. The symmetry of the nose seems to be more important than that of the lips. Dynamic asymmetries
Highly conspicuous directional asymmetries can be temporary ones. 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. Facial averageness vs. symmetry
Experiments suggest that symmetry and averageness make independent contributions to attractiveness. Aging
Facial symmetry is also a valid marker of cognitive aging.