From http://www.medicinenet.com/script/main/art.asp?articlekey=35284&page=3
It was found, by Wedekind and his team, that how women rate a man's body odor pleasantness and sexiness depends upon how much of their MHC profile is shared. Overall, women prefer those scents exuded by men whose MHC profiles varied the most from their own. Hence, any given man's odor could be pleasingly alluring to one woman, yet an offensive turnoff to another.
Raters said that the smells they preferred reminded them of current or ex-lovers about twice as often as did the smells of men who have MHC profiles similar to their own, suggesting that smell had played a role in past decisions about who to date. MHC-similar men's smells were more often described as being like a brother's or father's body odor...as would be expected if the components of smell being rated are MHC determined.
Somewhat more surprising is that women's evaluations of body odor intensities did not differ between MHC-similar and MHC-dissimilar men. Body scent for MHC-dissimilar men was rated as less sexy and less pleasant the stronger it was, but intensity did not affect the women's already low ratings for MHC-similar men's smells.
That strong odor turned raters off even with MHC-dissimilar men may be due to the fact odor is a useful indicator of disease. From diabetes to viral infection to schizophrenia, unusually sweet or strong body odors are a warning cue that ancestral females in search of good genes for their offspring may have been designed to heed. (In the case of schizophrenia, the issue is confounded--while some schizophrenics do actually have an unusually sweet smell, many suffer from delusions of foul smells emanating from their bodies.)
Nobody yet knows what roles MHC may play in male evaluations of female attractiveness. Females' superior sense of smell, however, may well be due to their need to more carefully evaluate a potential mates merits--a poor mate choice for male ancestors may have meant as little as a few minutes wasted, whereas a human females mistake could result in a nine-month-long "morning after" and a child unlikely to survive.
Perfumers who really want to provide that sexy allure to their male customers will apparently need to get a genetic fingerprint of the special someone before they can tailor a scent that she will find attractive.
The Swiss researchers found that women taking oral contraceptives (which block conception by tricking the body into thinking it's pregnant) reported reversed preferences, liking more the smells that reminded them of home and kin. Since the Pill reverses natural preferences, a woman may feel attracted to men she wouldn't normally notice if she were not on birth control--men who have similar MHC profiles.
The effects of such evolutionary novel mate choices can go well beyond the bewilderment of a wife who stops taking her contraceptive pills and notices her husband's "newly" foul body odor. Couples experiencing difficulty conceiving a child--even after several attempts at tubal embryo transfer--share significantly more of their MHC than do couples who conceive more easily. These couples' grief is not caused by either partner's infertility, but to an unfortunate combination of otherwise viable genes.
Doctors have known since the mid-1980s that couples suffering repeated spontaneous abortions tend to share more of their MHC than couples for whom pregnancies are carried to term. And even when MHC-similar couples do successfully bring a pregnancy to term, their babies are often underweight.
The Swiss team believes that MHC-related pregnancy problems in humans are too widespread to be due to inbreeding alone. They argue that in-couple infertility problems are due to strategic, unconscious "decisions" made by women bodies to curtail investment in offspring with inferior immune systems--offspring unlikely to have survived to adulthood in the environments of our evolutionary past.
Perfume; daily, soapy showers; convenient contraceptive pills---all have their charms. But they also may be short-circuiting our own built-in means of mate choice, adaptations shaped to our unique needs by millions of years of ancestral adversities. The existence of couples who long for children they cannot have indicates that the Western dismissal of body scent is scarcely benign.
How does body odor affect a woman's sexiness? Scientists don't know for sure, but they do know that a man's allure depends in part on how many immune system genes he shares with a potential mate.
Since it's known that women can detect genetic compatibility by smell--it's not that men can't but that so far no one knows--the onus is on females to sniff out a suitable squire.
Choosing a genetically compatible partner can be difficult it today's perfume rich postindustrial jungle, and getting your immune system genes profiled can be expensive. Before you run to a doctor for blood work to see whether your mate is a suitable match--and sire for your future children--try listening to your nose. (Unfortunately, the sniff test will only work if you're not taking birth control pills.)
It was found, by Wedekind and his team, that how women rate a man's body odor pleasantness and sexiness depends upon how much of their MHC profile is shared. Overall, women prefer those scents exuded by men whose MHC profiles varied the most from their own. Hence, any given man's odor could be pleasingly alluring to one woman, yet an offensive turnoff to another.
Raters said that the smells they preferred reminded them of current or ex-lovers about twice as often as did the smells of men who have MHC profiles similar to their own, suggesting that smell had played a role in past decisions about who to date. MHC-similar men's smells were more often described as being like a brother's or father's body odor...as would be expected if the components of smell being rated are MHC determined.
Somewhat more surprising is that women's evaluations of body odor intensities did not differ between MHC-similar and MHC-dissimilar men. Body scent for MHC-dissimilar men was rated as less sexy and less pleasant the stronger it was, but intensity did not affect the women's already low ratings for MHC-similar men's smells.
That strong odor turned raters off even with MHC-dissimilar men may be due to the fact odor is a useful indicator of disease. From diabetes to viral infection to schizophrenia, unusually sweet or strong body odors are a warning cue that ancestral females in search of good genes for their offspring may have been designed to heed. (In the case of schizophrenia, the issue is confounded--while some schizophrenics do actually have an unusually sweet smell, many suffer from delusions of foul smells emanating from their bodies.)
Nobody yet knows what roles MHC may play in male evaluations of female attractiveness. Females' superior sense of smell, however, may well be due to their need to more carefully evaluate a potential mates merits--a poor mate choice for male ancestors may have meant as little as a few minutes wasted, whereas a human females mistake could result in a nine-month-long "morning after" and a child unlikely to survive.
Perfumers who really want to provide that sexy allure to their male customers will apparently need to get a genetic fingerprint of the special someone before they can tailor a scent that she will find attractive.
The Swiss researchers found that women taking oral contraceptives (which block conception by tricking the body into thinking it's pregnant) reported reversed preferences, liking more the smells that reminded them of home and kin. Since the Pill reverses natural preferences, a woman may feel attracted to men she wouldn't normally notice if she were not on birth control--men who have similar MHC profiles.
The effects of such evolutionary novel mate choices can go well beyond the bewilderment of a wife who stops taking her contraceptive pills and notices her husband's "newly" foul body odor. Couples experiencing difficulty conceiving a child--even after several attempts at tubal embryo transfer--share significantly more of their MHC than do couples who conceive more easily. These couples' grief is not caused by either partner's infertility, but to an unfortunate combination of otherwise viable genes.
Doctors have known since the mid-1980s that couples suffering repeated spontaneous abortions tend to share more of their MHC than couples for whom pregnancies are carried to term. And even when MHC-similar couples do successfully bring a pregnancy to term, their babies are often underweight.
The Swiss team believes that MHC-related pregnancy problems in humans are too widespread to be due to inbreeding alone. They argue that in-couple infertility problems are due to strategic, unconscious "decisions" made by women bodies to curtail investment in offspring with inferior immune systems--offspring unlikely to have survived to adulthood in the environments of our evolutionary past.
Perfume; daily, soapy showers; convenient contraceptive pills---all have their charms. But they also may be short-circuiting our own built-in means of mate choice, adaptations shaped to our unique needs by millions of years of ancestral adversities. The existence of couples who long for children they cannot have indicates that the Western dismissal of body scent is scarcely benign.
How does body odor affect a woman's sexiness? Scientists don't know for sure, but they do know that a man's allure depends in part on how many immune system genes he shares with a potential mate.
Since it's known that women can detect genetic compatibility by smell--it's not that men can't but that so far no one knows--the onus is on females to sniff out a suitable squire.
Choosing a genetically compatible partner can be difficult it today's perfume rich postindustrial jungle, and getting your immune system genes profiled can be expensive. Before you run to a doctor for blood work to see whether your mate is a suitable match--and sire for your future children--try listening to your nose. (Unfortunately, the sniff test will only work if you're not taking birth control pills.)
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