Symmetrical faces are often considered to be more attractive. The idea that symmetry in faces is attractive because it indicates good health and therefore a good choice of mate has generated lots of scientific literature on the evolution of how humans pick mates. However, there are few large scale and long running tests to work out if subtle differences in facial symmetry really are a good indicator of health.
The team behind this paper undertook the first study of its type by analysing the symmetry of teenagers faces at age 15 and comparing their scores to health surveys completed throughout their lives. The survey data came from the Avon Longitudinal Study of Parents and Children and involved questionnaires filled in by a child’s care giver each year. The self-reported data helped the team work out how many years a child had had health problems, the different illness the child had had (for example measles, chicken pox and meningitis) and how many symptoms like coughing, diarrhoea or vomiting the child had had on average each year. Together these measures helped the scientists get an insight into the wellbeing of the children from birth.
The results of the team’s analysis showed that there was no significant association between the symmetry of the faces of the teenagers at 15 and their childhood health. The team didn’t find any difference in how the teens’ faces scored for symmetry between those who had had many of the conditions the survey’s probed for and those who had had few of them.
The team did however find a small but significant relationship between facial symmetry and IQ for the boys in the study but not the girls. The male teenagers who had more symmetric faces at age 15 had better scores on an IQ test taken when they were 8 years old than the teens with less symmetric faces. This results is ‘consistent with the idea that low facial asymmetry is associated with improved developmental outcomes,’ say the team.
The team say that their study shows that subtle differences in the symmetry of faces is not a reliable indicator of childhood health. Larger variations in facial symmetry do result from various genetic disorders and trauma in early development. The team say that preferences to find symmetrical faces more attractive even though subtle symmetries aren’t indicative of good health might have evolved not to provide marginal fitness benefits but ‘due to the potential costs associated with picking a mate with a serious developmental problem’.