A look at the peer-reviewed research on facial symmetry, why it's linked to attractiveness judgments, and the leading explanations for why humans respond to it.
The Basic Finding
Across dozens of studies using digitally symmetrized versions of real faces, researchers have found that more symmetrical faces are consistently rated as more attractive than the same face with natural asymmetries left in place. This holds across different cultures and age groups, making it one of the more replicated findings in the attractiveness literature.
Leading Explanations
The most-cited explanation is the 'developmental stability' hypothesis: facial symmetry may signal that a person experienced fewer disruptions (illness, poor nutrition, genetic stress) during development, since environmental and genetic stressors tend to produce measurable asymmetries. Whether observers consciously or unconsciously use symmetry as this kind of signal is still debated, but the correlation between symmetry and attractiveness ratings itself is well documented.
Everyone Has Some Asymmetry
No face is perfectly symmetrical — a landmark study comparing left and right face halves found measurable differences in the large majority of subjects, including models and actors typically held up as conventionally attractive. The research finding isn't that faces need to be perfectly symmetrical to be attractive, but that relative symmetry correlates with higher ratings on average.
Why This Matters for Styling
Because most style choices — a side part, an asymmetrical fringe, one-sided facial hair growth patterns — interact directly with a face's existing symmetry, understanding your own asymmetries (which side of your jaw is slightly wider, which eyebrow sits higher) is genuinely useful information before choosing a haircut or beard style, independent of any broader ideas about beauty standards.