Face Symmetry Is Sexy To Humans And Primates

According to a recent study published in the journal PLoS ONE,
researchers better understand why symmetry and sexual dimorphism are
key variables that determine how attractive a face is.



Faces are important in transmitting social information among humans,
and attractiveness is a quickly noted quality. Researchers
have wondered why it is that these traits are attractive and what the
link is between symmetry and sexual dimorphism - how masculine
or feminine a face seems.



Researchers have postulated that symmetry and sexual dimorphism
advertise genetic quality. That is, they are indicators of qualities
such as fertility. Others believe that the preference for these traits
is strictly a visual phenomenon, not a biological or reproductive one.
To evaluate the idea of a face's having the potential to advertise the
quality of a mate, researchers looked at interrelationships between
these two measures of quality.



Anthony Little (University of Stirling) and colleagues
measured symmetry and sexual dimorphism in the faces of humans (both
Europeans and African hunter-gatherers) and in a non-human primate (the
macaque). The researchers found a relationship between the two measures
in each group. Males and females with symmetric faces, in all samples,
also had masculine and feminine facial proportions, respectively.



The authors write: "Our results indicate that symmetry and sexually
dimorphic traits are related in male and female faces in humans, in a
modern western society and in a different society living under
conditions better approximating human evolutionary history, and across
species, both in humans and a non-human primate. We found symmetry was
related to sexual dimorphism using physical measurements of large
numbers of faces and perceptual tests based on the perceived sexual
dimorphism of faces that were most and least symmetric in our samples."



According to the authors, the findings provide support for the idea
that both sexual dimorphism and symmetry in faces advertise
quality, and there must be some biological mechanism that links the two
traits during development. They posit that having the symmetric and
sexually dimorphic trains may be a characteristic of individuals who
tend to be resistant to disease.



"Our finding of sex specific co-variation with symmetry, femininity for
females, masculinity for males, indicates then that both sexual
dimorphism and symmetry likely are signals advertising quality. We have
shown such a relationship in diverse human cultures and in a monkey
species, which suggests that signaling properties of faces are
universal across human populations and that facial advertisements of
quality may have arisen relatively early in the phylogeny of primates,"
conclude the authors.



Symmetry Is Related to Sexual Dimorphism in Faces: Data
Across Culture and Species

Little AC, Jones BC, Waitt C, Tiddeman BP, Feinberg DR, et al.

PLoS ONE (2008). 3(5): e2106.

doi:10.1371/journal.pone.0002106

Click
Here to View Article



About PLoS ONE



PLoS ONE is the first journal of primary research
from all areas of science to employ both pre- and post-publication peer
review to maximize the impact of every report it publishes. PLoS
ONE is published by the Public Library of Science (PLoS), the
Open-access publisher whose goal is to make the world's scientific and
medical literature a public resource.



About the Public Library of Science



The Public Library of Science (PLoS) is a non-profit organization
of scientists and physicians committed to making the world's
scientific and medical literature a freely available public resource.
For more information, visit plos



Written by: Peter M Crosta