Here are three article edits. They are all from the same magazine because I remember two of them and thinking it a curious subject for publication.
Thank you for asking so I could share!
Hunkier than thou
Scientists are finally succeeding where so many men have failed: in understanding why women find some guys handsome and others hideous
Dec 9th 2010 | from the print edition
WHEN it comes to partners, men often find women’s taste fickle and unfathomable. But ladies may not be entirely to blame. A growing body of research suggests that their preference for certain types of male physiognomy may be swayed by things beyond their conscious control—like prevalence of disease or crime—and in predictable ways.
Masculine features—a big jaw, say, or a prominent brow—tend to reflect physical and behavioural traits, such as strength and aggression. They are also closely linked to physiological ones, like virility and a sturdy immune system.
The obverse of these desirable characteristics looks less appealing. Aggression is fine when directed at external threats, less so when it spills over onto the hearth. Sexual prowess ensures plenty of progeny, but it often goes hand in hand with promiscuity and a tendency to shirk parental duties or leave the mother altogether.
So, whenever a woman has to choose a mate, she must decide whether to place a premium on the hunk’s choicer genes or the wimp’s love and care. Lisa DeBruine, of the University of Aberdeen, believes that today’s women still face this dilemma and that their choices are affected by unconscious factors.
In a paper published earlier this year Dr DeBruine found that women in countries with poor health statistics preferred men with masculine features more than those who lived in healthier societies. Where disease is rife, this seemed to imply, giving birth to healthy offspring trumps having a man stick around long enough to help care for it. In more salubrious climes, therefore, wimps are in with a chance.
[EDITED]
Another recent study by Dr DeBruine and others has tried to do just that. Its results lend further credence to the health hypothesis. This time, the researchers asked 124 women and 117 men to rate 15 pairs of male faces and 15 pairs of female ones for attractiveness. Each pair of images depicted the same set of features tweaked to make one appear ever so slightly manlier than the other (if the face was male) or more feminine (if it was female). Some were also made almost imperceptibly lopsided. Symmetry, too, indicates a mate’s quality because in harsh environments robust genes are needed to ensure even bodily development.
Next, the participants were shown another set of images, depicting objects that elicit varying degrees of disgust, such as a white cloth either stained with what looked like a bodily fluid, or a less revolting blue dye. Disgust is widely assumed to be another adaptation, one that warns humans to stay well away from places where germs and other pathogens may be lurking. So, according to Dr DeBruine’s hypothesis, people shown the more disgusting pictures ought to respond with an increased preference for masculine lads and feminine lasses, and for the more symmetrical countenances.
That is precisely what happened when they were asked to rate the same set of faces one more time. But it only worked with the opposite sex; the revolting images failed to alter what either men or women found attractive about their own sex. This means sexual selection, not other evolutionary mechanisms, is probably at work.
More research is needed to confirm these observations and to see whether other factors, like witnessing violence, bear on human physiognomic proclivities. For now, though, the majority of males who do not resemble Brad Pitt may at least take comfort that this matters less if their surroundings remain spotless.
http://www.economist.com/node/17672806
Tried to shorten it but keep some context.
The evolutionary psychologists tell us facial symmetry and hip-to-waist ratios are what really matter.
http://www.economist.com/...y_and_othe
This article here is less than half of the original piece:
[Edited]
Randy Thornhill of the University of New Mexico has gone further in his analysis of who mates with whom, and why. Over the past few years he has sought to find out just what it is that makes people attractive. And what he has found is that one of the most important factors is symmetry. Even if features are asymmetrical by only a millimetre or two it can have a detectable effect. Moreover, it is not just facial symmetry that matters, but the symmetry of the whole body—even things like the corresponding fingers of different hands being the same length.
He has also found, by reviewing the literature in co-operation with Anders Moller of the Université Pierre et Marie Curie, in Paris, that people are not alone in these preferences. Some 42 other species—including insects and birds, as well as other mammals—use at least some aspect of bodily symmetry to help choose their mates. His discoveries have provoked a number of follow-up projects, one of which he conducted jointly with Karl Grammer of the Ludwig Boltzmann Institute for Urban Ethology (LBI-UE) in Vienna. Together, Dr Grammer, Dr Thornhill and their research groups have refined the idea of what it is that makes for an attractive woman.
The body beautiful
First, they have found that men from around the world rank women (or, at least, photographs of women) from ethnic groups with which they are unfamiliar in the same order as men from those groups do themselves. This suggests that beauty is a less arbitrary notion than is sometimes claimed. (Similar experiments in which women rank men from different parts of the world have not yet been done, although Dr Thornhill has shown that symmetry is important in a woman’s choice of mates, too.)
Then, to try to work out just what it is that men everywhere are looking for, Dr Grammer and Dr Thornhill used standardised photographs of almost 100 white American women taken by Akira Gomi, a Japanese photographer. Mr Gomi took three shots of each woman—one of her whole body from the front, one of it from the back, and a close-up of her face. Men were then asked to rank the shots for physical attractiveness without seeing more than one picture of a particular woman. In the full-frontal picture, the woman’s face was blocked out so that the subject could only rank her on bodily features.
The result was that the rank of a woman in each of the three sets of shots was more or less the same. Again, this might not come as a surprise to the man or woman in the street. But it is actually quite surprising. Rather than a woman having, say, some genes that make for a beautiful face, while others conspire to give her ugly feet, the attractiveness of all her bodily features seems to be correlated. To try to find out just what it is, beyond mere symmetry, that turns men on or off, Dr Grammer and Dr Thornhill subjected the photographs to a statistical analysis of all their features.
The various measurements used in the analysis ended up clustered into four groups. These were referred to by the researchers as “body-mass”, “nubility”, “colour” and “androgynicity”. High scores in nubility (of which symmetry is a major component) and colour (a combination of skin colour—for the Austrian and American men in their sample, darker was better—and further aspects of symmetry) increased a woman’s attractiveness to men. Meanwhile, as women have often feared, high body-mass (not just weight, but overall podginess) and androgynicity (features that would look more appropriate on a man) reduced it.
And, lest it be thought that Dr Thornhill and his colleagues are interested only in the physical aspects of attraction, they have also investigated the relationship between bodily symmetry, mental faculties and general well-being. The results of these investigations suggest that the old saw about a healthy mind in a healthy body has much truth to it. A person’s degree of bodily symmetry does correlate quite closely with his or her IQ. It correlates with freedom from minor ills such as headaches and stomach pains, too. And, yes, men who have symmetrical bodies not only obtain more attractive mates, they tend to invest less effort in their relationships. They love ’em and leave ’em.
There is a reason for all this, of course. Bodily symmetry patterns are built up during embryonic development. Though the results may seem commonplace, development is a complex and sophisticated process that can easily be knocked off course. Many external “insults”, such as infections and poisons, can have this effect. How perfectly an embryo develops, therefore, is a mixture of how unlucky it is in the number of such insults that it receives, and how successful its genes are at coping with them.
That means that symmetry (ie, accurate development) not only indicates good health, of the sort that might make for a more effective parent; it is also quite likely to show that someone possesses genes that, when passed on to the kids, can keep their developmental process on track. That is why symmetry is sexy.
Sex in the air
None of this, however, answers the question of why sex is there in the first place. That may seem an odd thing to worry about, but common sense suggests that asexual reproduction would be better than sexual reproduction. This is because it would take only one animal to produce a litter of offspring rather than two, so the number of an individual’s descendants would increase much faster. If sex halves the rate at which those descendants are multiplying, it needs a very good compensating reason for existing.
One possible reason, which was dreamed up by Bill Hamilton of Oxford University, is that the gene-shuffling in sexual reproduction keeps parasites confused. If all of an animal’s offspring have the same genes (the usual consequence of asexuality), all can be wiped out by a parasitic infection that “likes” that particular genetic combination. And there are a lot of parasites out there: viruses, bacteria, protozoa, fungi, a slithering variety of worms and even fleas and lice.
A consequence of Dr Hamilton’s theory is that a good mate should be good at fending off parasites. Not only is such a mate healthy now, its progeny are likely to enjoy that state, too. Indeed, Dr Milinski’s work with his sticklebacks was an early demonstration that the Hamilton hypothesis may be true.
In mammals, one of the most important sets of genes involved in keeping the body parasite-free is the one that carries the plans for the major histocompatibility complex (MHC). This is part of the immune system. It consists of a collection of highly variable proteins that are involved in recognising invading parasitic organisms. Because MHCproteins are so variable, no individual carries a complete set of them. And because the parasites, too, are capable of evolving to get around the immune system, it makes sense to make the MHC genes in one’s offspring as variable as possible.
An animal could therefore learn a lot if it were able to study the MHCs of potential mates. By doing so it could avoid mating with individuals that carried genes for MHCproteins similar to its own. Just as importantly, it could also reduce its risk of inbreeding, since close relatives share MHC genes. Inbreeding reduces genetic variety, allowing genetic diseases to appear (the effects of failed genes inherited from one parent are no longer masked by functional ones from the other).
It might seem implausible that animals could work out much about each others’ MHCsystems, but a long-term project led by Wayne Potts at the University of Utah has shown that mice, at least, are able to do so. More surprisingly still, Claus Wedekind, one of Dr Milinski’s colleagues at Berne, has produced evidence that the same thing may be going on in people—whose MHC genes are more properly known as Human Leucocyte Antigen, or HLA, genes.
Mice with similar MHC genes rarely mate with each other. If a female finds herself corralled into the harem of an immunologically unsuitable male, she will go out of her way to copulate with more suitable neighbouring males. Despite the vigilance of the harem masters, some 46% of mice are sired by outsiders in this way, and Dr Potts’s experiments have demonstrated that the choice is made on the basis of smell. Cross-fostering experiments recently carried out by Dustin Penn, one of Dr Potts’s collaborators, have shown that a young mouse learns the scent to avoid by smelling its litter-mates—another example of imprinting.
Dr Wedekind was not able to do a similar experiment with people. But, by asking volunteers to sniff T-shirts that had been worn by members of the opposite sex, he has been able to show that the pleasantness of the smell depends on the differences between the HLA genes of the volunteer and those of the T-shirt wearer. And work currently being carried out by Carol Ober at the University of Chicago suggests that these smell preferences may translate into actual choices for human mates.
Just what it is that mice (and, come to that, people) are actually smelling has not yet been established. It may be breakdown products from the MHC proteins themselves, or it may be the secretions of bacteria that are able to escape the attentions of particularMHC proteins. But other work presented to the conference in Vienna reinforces the idea that the human sense of smell is much more important in mate selection than even perfume manufacturers have dared to dream.
In separate studies Dr Thornhill and Anja Rikowski, of the LBI-UE, have adopted Dr Wedekind’s methods to see if there is a link between the attractiveness of a person’s body odour and his or her symmetry. They have found that there is. And Astrid Jütte, also of the LBI-UE, believes she has shown an even more direct link between scent and sexual attractiveness—and this time it is something that could be bottled.
Dr Jütte has assailed male nostrils with a synthetic mixture of the fatty acids that are found in human vaginal secretions. She has found that when men inhale this mixture their sexual judgment goes to pot. Photographs of women to whom they would not normally give a second glance suddenly become attractive. Indeed, the worse a woman’s picture rates without the chemicals, the larger the leap she undergoes in a man’s estimation when he is sniffing them. Even the most acutely tuned genetic responses, it seems, can be subverted environmentally by the correct stimulus.
This does, however, raise a query. Why would evolution have produced men whose lust could so easily be subverted? The answer to that remains to be seen, though it might simply be that the secretions indicate female sexual arousal and thus an increased chance of a successful seduction. That would make sense, for while it seems that natural selection may have toned down the promiscuous male impulse in humans, the anguish of wives throughout the centuries shows that such promiscuity has not yet been abolished.
http://www.economist.com/node/155444
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