It’s not fair, but it’s true: some people just look prettier and more attractive than others. And as if that were not enough, beautiful people live easier lives – from the nurse who gives more attention to the pretty baby, the schoolteacher who is more likely to blame the ugly kids to the salary negotiations where beauty often results in a bigger paycheck.
From a biological perspective it has become clear in recent years that beauty is not a fleeting phenomenon which, like fashion, changes with time and across cultures. Rather, behind all this beauty lies a biological signal that informs the surroundings of how healthy we are.
The face appears to be particularly important as a signaling device. Biologist Markus Rantala of Turku University, shows that attractive faces signal different things in men and women.
A STRONG IMMUNE SYSTEM IS ATTRACTIVE
A year ago, Rantala and colleagues found that the attractiveness of men’s faces is related to how strong their immune systems are.
They found that the higher the men featured in the women’s ratings, the stronger the men’s immune response to a vaccine against hepatitis B.
A STRONG IMMUNE SYSTEM CAN WITHSTAND HIGH TESTOSTERONE LEVELS
The study found that the higher the women’s levels of stress hormones, the lower the men ranked the attractiveness of their faces.
There are, in other words, many indications that the attractiveness of men’s faces is evolutionarily linked to the immune system.
BUT WHAT ABOUT WOMEN’S BEAUTY?
It is tempting to think that the immune system also plays a part in women, and now Rantala’s research group has repeated the experiment with the hepatitis B vaccine on women.
They picked the hepatitis B vaccine because hepatitis B is one of the most common viruses, so it may be ecologically and evolutionarily relevant in the sense that our immune system can be selected to respond to it.
STRESSED WOMEN HAD THE LOWER SCORE
The researchers found that the higher the levels of stress hormones, the lower the rating of the women.
“This is actually quite logical, because we know that stress hormones inhibit the female sex hormone, and if the stress level is very high, it can make the woman infertile.”
A Pretty Face Should be Neither Thin nor Thick
Our study shows that if a women wishes to look attractive, she should try to keep her stress levels down.
So this could indicate that men pick their mate based on health and fertility, while women pick their mate partly based on the short-term risk the he might infect her with a disease, and partly based on whether he can produce children with strong immune systems.
Beauty is a Broad Concept
Our concept of beauty is not, of course, limited to the facial features mentioned in this study. Other factors, such as youthfulness, body proportions, symmetry and scents play a role too.
“But facial attractiveness is one of the most important factors – more important than e.g. body shape,” says Rantala.
”Our study shows that if a women wishes to look attractive, she should try to keep her stress levels down.”