The colour of love
A researcher looks at the science behind attraction and finds that skin lightness may not be all it’s cracked up to be.
SOME say faces are a window to the soul. Studies on the science of attraction, however, suggest it could a valuable source of information for those in search of a sexual partner.
In other words, beauty is not some arbitrary concept. It’s an advertisement, reflecting aspects of our genetic and reproductive health.
Evolutionary psychologists have been studying the factors underlying facial attractiveness for nigh on three decades and beauty, it seems, has a formula. Symmetry, averageness, masculinity and femininity are among the main ingredients.
The theory is that each trait is linked to some otherwise invisible aspect of our fitness. A lack of facial symmetry, for example, could indicate a lack of stability during development – the person may have suffered from a high number of infections, indicating a less robust immune system.
Or the hormones resulting in overtly feminine or masculine features, such as oestrogen and testosterone, may also signal a higher level of fertility or virility.
In other words, our concept of beauty may be nothing more than a long-term strategy for mate selection.
For these assumptions to be true, however, there has to be a series of links, evidence connecting the trait in question to our overall concept of “attractiveness”.
Researchers may have been good at linking traits with attractive appearance, but there has been less success linking these traits to some aspect of real health.
One of the few facial features that has recently been producing reliable evidence, however, is skin colour or shade – a relatively new area within the field of facial attraction.
Up until four years ago, most studies on facial attractiveness have been focused on the shape of the face or the texture of the skin.
It was only in 2009 that scientists published a fascinating study on our preference for skin colour. Dr Ian Stephen, an assistant professor in the School of Psychology at University of Nottingham’s Malaysia Campus, has studied the science of sex and attraction, and posits that making ourselves more attractive to the opposite sex may involve as simple an act as changing our diet.
Colour is skin deep
When Dr Stephen set out to look at how skin colouration affects our perceptions of health and attractiveness, he was expecting people to favour lighter skin tones.
After all, the skin-colour debate had been raging for quite a while.
“It came out of the question, why are people in Europe so pale?” he says. “It’s obvious why you need to be dark-skinned near the equator – melanin protects you from harmful UV rays and reduces your likelihood of sunburn and skin cancer.
“But there’s not any obvious reason why you should be really pale in Europe.”
Genetic drift – a concept which says that if you take away the need for dark skin, there could be a gradual accumulation of DNA muta- tions resulting in pale skin – was dismissed as an explanation.
The time-scales that would be required for this to occur were simply insufficient.
A more promising theory revolved around the suggestion that low light levels in Europe would actually make high amounts of melanin in the skin a disadvantage.
Blocking out too much sunlight could contribute to a deficiency in Vitamin D, which can lead to rickets, a bone deformation that used to be fairly common among Britain’s nonCaucasian community.
Still, this argument falls short of explaining why there are plenty of dark-skinned people in other regions of the far north. Any suggestions of a more recent historical migration, by dark-skinned people from the tropical belt, are not supported by known migration patterns.
Then there was another school of thought, which put forth sexual selection as an alternative explanation.
What if lighter skin is more attractive?
Anyone taking note of the cosmetics market in Asia will be aware of the wide array of skin-lightening products available.
This was the line of inquiry Dr Stephen decided to pursue during his PhD at the University of St Andrews in Scotland.
Apparent cultural ideals, however, are not always as representative. His investigations into the role that skin colour plays in our perceptions of health and attractiveness yielded some surprises.
Instead of lightness, redness and yellowness were more important, concluded a paper he co-authored back in 2009. The question was, why? That redness is an important factor didn’t come as too much of a surprise.
Our bodies run on oxygen, supplied via the blood, which is delivered via millions of tiny little vessels called capillaries.
It is the blood flow through capillaries in the skin which create a nice red flush. And a nice, red flush is a sign of healthy heart and lungs.
“Oxygenated blood is bright red,” explains Stephen, “whereas de-oxygenated blood is still red, but darker and more purple.
“Hence, people with serious lung illnesses who end up looking a bit blue, and people with heart problems, often look pallid.”
Yellow, however, was a bit more of a mystery.
Most people know about melanin, which is the dark brown pigment in our skin that contributes to our “yellowness”. However, Dr Stephen was also interested in carotenoids, the red-orange-yellow pigment that also makes an important contribution to the yellowness in our skin.
“That’s when we came across all this research about birds and fish, and the role of carotenoids in sexual selection, and thought, maybe that’s what’s happening in humans...”
Carrots and Ferraris
If you were a female bird, you might find a male’s bright yellow feathers irresistible.
Evolutionary biologists have a theory for why that is – it’s called the handicap principle.
A hypothesis originated by biolo- gist Amotz Zahavi back in the 1970s, it is based on the idea that females choosing their mates leads to the evolution of “honest” signals of health and fertility.
Carotenoids, the pigment derived from food sources responsible for the bright yellow feathers, are in fact a very important currency of the immune system.
“They are antioxidants, which means they neutralise reactive oxygen species – chemical by-products of the body’s metabolic processes – that basically whizz around and damage whatever they bash into, such as proteins and DNA,” Dr Stephen explains.
“So if a bird can afford to store lots of carotenoids in its feathers, leaving less for its immune system, it must be in good health.”
In other words, bright yellow feathers are a costly, and therefore “honest”, way of signalling good health.
Humans do something similar, says Dr Stephen, recounting an analogy often shared with his students: “Think about men who drive Ferraris. A Ferrari doesn’t actually do anything a cheap car doesn’t. Ok, maybe it goes a bit faster. But in some ways, it’s actually worse, because you can fit fewer people and luggage in, right?”
Ultimately, what’s important about Ferraris is they are loud, look cool, and are really really expensive.
“It’s conspicuous consumption, to borrow a term economists would use.
“The very purpose is to show off how much money you’ve got.”
Ferraris signal wealth. Carotenoids signal health.
It’s just that the latter incurs a metabolic cost, instead of a financial one. And humans do both. Dr Stephen’s 2009 study enabled people to make colour adjustments via software to a series of Caucasian faces.
Participants increased skin redness the most, then yellowness and lightness.
The same tests performed on African faces yielded similar results, as did Asian faces. In fact, it was searching for the East Asian component that led Dr Stephen to set up camp at the University of Nottingham’s Malaysia Campus.
Interestingly, colour only seems to be important within our own ethnic groups.
“Probably because we’re more familiar with our own group and can detect more subtle shifts in colour,” he says.
The colour code
The next step was to find out how sensitive people were to changes in colour.
Pretty sensitive, it turns out, when it comes to red, but less so for yellow and not much at all for lightness.
Tan Kok Wei, a PhD student at Dr Stephen’s laboratory, used computer software to manipulate colour pixels in the skin portions of photographs of faces, objects and colour patches.
Study participants were unable to detect the same changes in objects or colour patches when it came to red, but were better at detecting changes in objects when it came to lightness.
This means we have a special affinity for seeing red in faces, which Stephen. just health, For because save wrath could potentially
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The attraction spectrum: evolutionary psychologist Dr Ian Stephen and his PhD student Tan Kok Wei using a spectrophotometer to known as ‘lightness’ of the skin, which is determined by the concentration of melanin in the skin.
Studies show that redness, yellowness and lightness play a role in how we perceive attractiveness