In mate selection, people have been shown to have a preference of 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