Facial symmetry is an indicator of good genes and that is exactly why symmetrical faces are preferred.
Many say it is cultural programming. What features we find attractive in a human face is largely shaped by experience and education.
However, some education is instilled in us even before birth by evolution so that we learn to distinguish attractive faces from unattractive ones without prior experience. A study showed that neonates, who have no prior experience or social education, spend more time looking at faces that adults perceive to be highly attractive.
Symmetrical faces is just one of the few characteristics that make faces appear attractive. Across different societies and cultures symmetrical facial features in both genders are deemed as attractive.
But, why do we like symmetrical faces?
Face attractiveness test
Facial features convey information about a person’s overall health and reproductive status. It is an indicator of good genes. Our nervous systems have been programmed by natural selection to perceive faces of healthy and reproductively viable individuals as attractive. So, in a face attractiveness test a person scoring higher is more fit that the person scoring less. When high-school students with attractive faces were followed up they were found to live longer than their lesser attractive classmates. In another study, men who scored higher in the scale for attractiveness had better quality and highly fertile sperm.
The ability to resist diseases or signs of a strong immune system is also communicated through the face. Men who are judged by women as having attractive faces were found to be heterozygotic at the Major Histocompatibility Complex Loci. And, by now we all know, how important having genetic diversity in the MHC loci is for better immune function. Men and women who score higher in the facial attractiveness test also deviate less from facial symmetry. Bilateral symmetry in facial features is an indicator of good health and fitness. It is the outcome of normal development, free of genetic anomaly and parasitic infections.
Why is face symmetry attractive?
Human bodies possess bilateral symmetry along the sagittal plane. Symmetry is produced when both the left and right side develop together in harmony. Such harmony is only possible when genes in organ forming cells positioned on either sides of the body are switched on at the same time and stay active for the right duration, releasing chemical messengers and gene transcripts in the right dosage.
Similarly facial symmetry is an indication of stable development and lower mutation load. For a face to develop symmetrically genes on either side of our face must function in sync mirroring each other with perfect harmony. Our nervous system has learnt to take up such cues involuntarily due to years of evolution and natural selection.
Facial symmetry also mirrors higher ability to resist diseases and infections. Injury, inflammation, infections, allergies, metabolic diseases and even malnourishment can lead to facial asymmetry. A stronger immune system equips the person better to fight off such ailments and restore symmetry to some extent. Mate selection is highly competitive where only the best and healthiest candidates are successful at securing a mate. An ongoing disease manifesting as facial asymmetry gives a telltale sign of infection which leads to avoidance of the diseased individual by prospective mates.
Since facial symmetry is an indicator of good genes, choosing partners with near-perfect facial symmetry confers genetic advantages to the offspring. Science call it the Evolutionary Advantage Theory.
Are faces symmetrical?
The previously mentioned law of attraction says that people in general prefer symmetrical faces. But, are real human faces truly symmetrical?
Perfectly symmetrical faces are rare to come by, but they do exist. Data says that only 2% of the world’s population has perfect facial symmetry.
Despite its hype facial symmetry is not the sole criteria of attraction between the sexes or not as influential as the weightage previously conferred on it. In fact perfectly mirrored faces are perceived as unnatural and a slight asymmetry is often viewed as attractive.
Many other factors interact with facial symmetry to make a face appear as attractive. Skin quality, sexual dimorphism markers and averageness of facial features besides symmetry together decide the attractiveness score of a human face.
So, the next time you look in the mirror and find an ear a few millimeters higher than the other or the right eye slightly larger than the left one, understand that it is normal. Such slight asymmetry doesn’t make you any less attractive. Instead, focus more on your health and mental wellbeing. A healthy body and a balanced mind can compensate for the slight genetic shortcomings that prevents the achievement of a perfectly symmetrical face.