Symmetry and perceived facial attractiveness: A monozygotic co-twin comparison

Symmetry is a major correlate of physical attractiveness across species, in cluding humans. Investigating the nature of this relationship has been diff icult, however, for several reasons, including the facts that variance in s ymmetry is attributable to more than one source and is often correlated wit h other variables related to attractiveness. This study assessed the role o f facial symmetry in relation to perceptions of facial attractiveness. Some of the natural covariates of symmetry were controlled for by comparing the symmetry and attractiveness differentials between monozygotic co-twins, wh o are genetically, but not developmentally, identical. The more symmetric t win of a pair was consistently rated as more attractive, and the magnitude of the difference between twins in perceived attractiveness was directly re lated to the magnitude of the difference in symmetry.