William RevilleScience of Life
We each find that some people look more attractive to us than others. Much research has been carried out to identify the features that appeal to us. There is a long list of physical features that almost everybody finds attractive and it seems that evolution has hardwired us in this regard. However, we also differ significantly from each other with regard to what we find attractive and this seems to be determined by our individual life experiences – in this sense beauty is in ‘the eye of the beholder’.
Many studies have shown that facial symmetry is a powerfully attractive feature. A face that is equal on both sides tells the viewer, on an unconscious level, that the bearer of the face has good genes and would make a good mate. An asymmetric face hints at a less than harmonious development in the womb, predisposing the bearer to poor health and predicting that he/she would make a poor quality mate.
Attractive
Other facial features are also found to be universally attractive. Apparently the type of face that we find most attractive is not a face that dramatically stands out from the crowd but an ‘average’ face – that is an average of all the faces we have seen in the past. We like faces where the distance from the eyes to the mouth is about 36% of the length of the face and we like the distance between the eyes to be 40% of the width of the face.
The importance of symmetry goes beyond the face. Women with symmetrical breasts are more fertile than women who are a bit lopsided and wives whose husbands have symmetrical bodies have most orgasms.
Symmetry is important across the entire animal kingdom – male flies with the most symmetrical wings win the most mates, bees are attracted to symmetrical flowers (they carry the most nectar), male swallows with symmetrical tail feathers attract more females, and so on.
If you and I were asked to rate the attractiveness of the same faces we would agree about 50% of the time. This agreement is probably down to facial symmetry and the other facial features I already listed. But why would we disagree the other 50% of the time?
A recent study by Jeremy Wilmer and others in Current Biology addresses this latter question. The researchers studied the facial preferences of 547 pairs of identical twins and 214 pairs of fraternal twins. The results showed that even though identical twins are genetically identical to each other and were reared in the same family environment they are frequently very different from each other in their choice of faces they find attractive. The authors conclude that our personal experiences, which often differ greatly from one person to another even when people are reared together, very much inform whom we find attractive. On the other hand the study showed that the ability to recognise faces is highly hereditable.
Evolution has also programmed us to pay attention to body shape when we assess the attractiveness of the opposite sex. Men prefer a waist to hip ratio of 7:10 in a woman and are also attracted by a generous bust. Breast size and hip width are important factors in fertility, childbirth and rearing. Women are attracted to a waist to hip ratio of 9:10 in a man. Women also like a man with a big jaw and a prominent brow. Men are attracted to women who smile but this doesn’t apply the other way around.
Hands are also revealing. In men there is a link between finger length and the levels of testosterone to which the foetus was exposed in the womb. The greater the ratio between ring finger length and index finger length the higher the testosterone level and this augers well for high sperm count, good fertility and a healthy heart. However, studies also indicate that men with longer ring fingers are more likely to be promiscuous. And you thought that homing in on the ring finger could only tell you whether he was married or not!
It is said that gentlemen prefer blondes although a recent study to find the most beautiful woman in the world picked a brunette. However, there is no doubt that blondes are popular.
Combination
The Caucasian blue eye/blond hair combination evolved in northern Europe about 11,000 years ago. When the ice sheets retreated at the end of the ice age and populations moved northwards, being blonde conferred an evolutionary advantage. The lack of skin pigmentation allows the ultraviolet rays of the weaker sun to penetrate deeper to synthesise Vitamin D which is essential to good health. Blonde women were not only likely to be healthier than their darker rivals but they also stood out and were therefore more likely to be chosen by the male hunters.
And finally, at the risk of inducing all my female readers to fall hopelessly in love with me, could I direct your attention to the small photograph of yours truly that accompanies this article. As you see, this symphony of symmetry and proportion nicely illustrates many of the attractive features I describe in this article. You cannot see my ring finger, but you can take my word that it is a beauty!
William Reville is an Emeritus Professor of Biochemistry at UCC http://understandingscience.ucc.ie
