Symmetry is attractive to the human eye

Today, this symmetry has been scientifically proven to be inherently attractive to the human eye. It has been defined not with proportions, but rather with similarity between the left and right sides of the face. Thus, the Greeks were only partially correct.

By applying the stringent conditions of the scientific method, researchers now believe symmetry is the answer the Greeks were looking for.

Babies spend more time staring at pictures of symmetric individuals than they do at photos of asymmetric ones. Moreover, when several faces are averaged to create a composite -- thus covering up the asymmetries that any one individual may have -- a panel of judges deemed the composite more attractive than the individual pictures.

Victor Johnston of New Mexico State University, for example, utilizes a program called FacePrints, which shows viewers facial images of variable attractiveness. The viewers then rate the pictures on a beauty scale from one to nine. In what is akin to digital Darwinism, the pictures with the best ratings are merged together, while the less attractive photos are weeded out. Each trial ends when a viewer deems the composite a 10. All the perfect 10s are super-symmetric.

Scientists say that the preference for symmetry is a highly evolved trait seen in many different animals. Female swallows, for example, prefer males with longer and more symmetric tails, while female zebra finches mate with males with symmetrically colored leg bands.

The rationale behind symmetry preference in both humans and animals is that symmetric individuals have a higher mate-value; scientists believe that this symmetry is equated with a strong immune system. Thus, beauty is indicative of more robust genes, improving the likelihood that an individual's offspring will survive. This evolutionary theory is supported by research showing that standards of attractiveness are similar across cultures.

According to a University of Louisville study, when shown pictures of different individuals, Asians, Latinos, and whites from 13 different countries all had the same general preferences when rating others as attractive -- that is those that are the most symmetric.