Facial symmetry key to good looks
The more symmetric your face, the more attractive you are to others, according to University of Queensland research.
School of Psychology research consultant Dr Linda Mealey and honours student Ruth Bridgstock asked one group of 75 undergraduate students to rate symmetry and another 75 students to rate attractiveness, of 43 sets of identical twins.
To assess symmetry, each twin's image was manipulated to create two faces - one composed of two right sides of the original face and the other composed of two left sides of the original face.
A high attractiveness rating correlated with a high level of facial symmetry, Dr Mealey said.
"We can say that 50 percent of the attractiveness difference between the co-twins can be explained by a symmetry difference. We don't know what factors account for the other 50 percent," she said.
Hers is the first study to test the impact of symmetry on judgements of attractiveness using identical twins. Past studies have been hampered by the fact that people subconsciously take into account other factors such as hair and eye colour or face shape.
As the genes controlling the development of the left and right side of the face are identical, differences in the appearance of the two sides are a direct result of developmental stress, Dr Mealey said.
"The more asymmetric a person's face, the more disruptions they have had to their physical and mental health, both before and after birth. These include sickness of the mother while she was carrying the baby, nutritional deficiencies, disease or even psychological stress," she said.
"Therefore facial symmetry is an indicator of good health. Healthy people (those with greater facial symmetry) are considered more attractive therefore increasing their chances of mating and having offspring. This is nature's way of ensuring the best survival chance for the next generation.
"Identical twins are a wonderful accident of nature as the genetics are already controlled. Any symmetry differences are entirely due to environmental disruptions, either in the mother's womb or during childhood and adolescence growth spurts."
The study sheds new light on how people make attractiveness judgements about others as well as supporting the theory that facial symmetry can be used as a measure of health.
"Previous studies have shown that facial symmetry is an excellent indicator of health, such as whether a woman has an increased risk of premature birth or the presence of schizophrenia," Dr Mealey said.
She said people mostly made assessments of another's facial symmetry subconsciously on first meeting them, but the desire for facial symmetry appears in our everyday life in other ways.
"When women apply make-up, they will cover a blotch on one side of the face or pluck their eyebrows to achieve symmetry. People seeking plastic surgery are often wanting to create a more symmetrical face or feature," Dr Mealey said.
The study was completed last year from photographs obtained from Professor Grant Townsend, Dean of Dentistry at the University of Adelaide. Professor Townsend is conducting a separate study on dental symmetry between pairs of identical twins.
Dr Mealey's study will soon be published in the Journal of Personality and Social Psychology. She has also presented results at both the Human Behaviour and Evolution Society conference in the United States of America and the International Society for Human Ethology conference in Canada.
Media contact: Dr Mealey (telephone 07 3365 6727).
