I Love Your Immune System Genes
Have We Solved the Mystery of Mutual Attraction?
A person who is protected from all controversial ideas is as vulnerable as a person who is protected from every germ.
- Jane Smiley
by Michael Hanlon
Where love's concerned, it's the oldest cliché in the book. Cupid's arrow, we like to think, is aimed at opposites who, in a romantic universe, turn out to make the perfect pairings. She extremely tall, he a dwarf. She tidy and well organised, he a slovenly eccentric. She open, dilettante and forgiving, he obsessive and secretive. Beauty and the beast.
The trouble is, no one has much of a clue whether this is actually true, or if it is, what the basis of the attraction of opposites might be. Hard evidence has emerged to suggest that this romantic notion may have a grain of truth in it. Opposites, at least on a very limited genetic level, may have what it takes to make a successful and long-lasting pairing. In a report in the journal Psychological Science, geneticist Christine Garver-Apgar at the University of New Mexico found in heterosexual couples that the more similar a particular set of genes (linked to immune system development), the less sexually responsive a woman was to her partner, and the more likely she would be unfaithful.
The thinking goes that seeking out a mate with a different immune system ensures that any children the couple have will benefit from a broader immunity against disease. In a New Scientist article commenting on the findings, it was suggested that this genetic attraction could one day lead to a DNA test for women, to reveal how likely it was that she would remain faithful to her partner (men seem to be unaffected by the similarities in these genes). This is not the same as saying couples who are alike will fall apart. A man and a woman could look like sister and brother and yet their immune system genes might be very different - meaning she would not be particularly likely to look elsewhere.
But it opens a chink of light into the murky area of how our genes, our bodies and our emotions come into play when deciding who we choose for a mate, and how likely it is that our partnerships will be permanent. When it comes to crude similarities between partners, we can all think of examples when opposites do attract. We all know a mousy wife married to a thrusting, alpha male, or a sheepish man paired with a sexually aggressive Amazon.
The history of love is littered with famous examples. Marilyn Monroe and Henry Miller, the pneumatic movie star and the intellect with a brain the size of a planet. Salman Rushdie and his wife Padma Lakshmi, he the author of books too well written for anyone actually to finish, she a Bollywood starlet. More often than not, the pairing is this way around. It is hard to think of many examples where the beauty has belonged to the male and the brains to the female.
But is this just a case of power or fame, or fortune acting as an aphrodisiac? Or is there something more subtle, and fundamental, going on? The first thing to say is there is a remarkable degree of consistency, across all races, cultures, nationalities and times, about what is considered attractive in both males and females. Study after study has shown that men tend to prefer women with youthful, symmetrical features, of average weight and build, with fairly well-developed breasts and hips, long hair and long fingernails.
These features are suggestive of good health and good levels of the hormones œstrogen and progesterone. For women, the ideal man is tall, with a strong brow and jaw, a triangular torso and, like men, women look for signs of symmetry and health suggestive of genetic "fitness" to reproduce. Interestingly, a woman's preference for a "manly" man increases strongly during the time of ovulation, with a preference for a more feminised, "nurturing" appearance taking precedence at other times of the month. This suggests females may have traditionally preferred different men to bring up their children to those who actually fathered them biologically.
Last year, a University of California study showed that women are very good at assessing a man's biological potential just by looking at his face. Shown photographs of 29 men, a group of volunteers were able to rank the men in terms of their testosterone levels and by their supposed interest in children. The men ranked most attractive for a short-term relationship ranked highest for the male hormone, whereas those men rated good child-nurturers ranked high as a long-term prospect.
But if people selected mates only on this basis we would all have to look like either Brad Pitt or Angelina Jolie. Clearly we do not. So individual preferences, as well as luck of the draw, must play a huge part. In fact, all the evidence shows that - despite this latest study in Nature magazine - people tend to prefer partners pretty much like themselves. A 2003 study, reported in the Proceedings of the National Academy of Sciences, showed that of 1,000 young New York volunteers, people's stated preferences in a partner correlated with their opinion of themselves.
Thus wealthy, educated, high-achieving people of both sexes wanted partners who were also rich and successful. The tall preferred the tall, the very short the short. People look for the safety of compatibility rather than the dangerous excitement of being at odds. In fact, the ideal partner for most would be their similar-aged sibling. For obvious ethical reasons, few studies have been done on sexual attraction between brothers and sisters, but there have been a number of cases where siblings, unaware of each other's existence, have met as adults and immediately fallen in love (see Genetic Sexual Attraction further on in this section for more on this topic).
The fact this doesn't happen often has probably got less to do with the incest taboo than with a protection mechanism that has evolved to encourage genetic diversity; people simply don't fancy those they grew up with, whether or not they are related. According to one theory, the natural tendency to prefer similar partners may be becoming more pronounced, at least in some social classes. The Cambridge neuroscientist Simon Baron Cohen (a cousin of Borat star Sacha) has proposed that there are innate differences between male and female brains.
It is possible that one of the causes of the autism epidemic is the growing tendency for successful men to marry and have children with powerful, assertive "masculine brain" females. A hundred years ago, such a man may have preferred a dippy blonde on his arm, while nowadays they prefer someone who is on their intellectual and professional level. Tony Blair and former the US President Bill Clinton illustrate this trend. One interesting side effect may be that extreme "masculine" traits - and autism may be one - could be magnified.
There may be truth in all or some of this, but the harsh fact is that we tend to overestimate just how much free will we have when choosing our partner. Our genes may be a good way of predicting how long couples will stay together, but they are a terrible way of predicting who will get together. Cupid does not so much aim a well-targeted arrow as fire a scattergun in random directions. Opposites attract, but the similar may be far more beguiling. Of one thing we can be certain: it will be a long time before dating agencies offer a reliable DNA test for compatibility.
Source: dailymail.co.uk 15 January 2007
Partner Choice "Shaped by Father"
Much as she might hate to admit it, a woman's choice of partner may depend a lot on her own father. Scientists have found women who were treated well by their dad during childhood are attracted to men who resemble their father facially. But the link is lost on women who did not have good relationships with their fathers. The research, led by a psychologist at Durham University, is published in Evolution and Human Behaviour. Author Dr Lynda Boothroyd said the findings added to our understanding of how we become attracted to certain types of people. She said such knowledge could have implications for fields such as relationship counselling.
Women in the study were asked to rate pictures of men's faces for attractiveness, and assess their relationship with their fathers. The team compared the facial features of the men in the study, such as the width of nose and lips, to pictures of the women's fathers. They found in women who reported more positive relationships with their fathers, there was a link between the faces the women found most attractive and their father's faces.
The study was the first of its kind to use facial measurements to assess the similarity of the faces. Dr Boothroyd said previously it had been thought selecting partners similar to our parents was because our parents are the people from whom we learn what our species looks like. But she said the research shows there is a more emotional component involved in the process.
Dr George Fieldman, a psychologist and lecturer from Buckinghamshire Chilterns University College, said the results were "very interesting". He said it seemed to show an adaptive response to being treated well by our parents - women are making the underlying assumption people who look like their father might act in the same way as him. Hence they are attracted to people who look similar to their dads only if their fathers treated them well as children. Dr Fieldman said: "The paper shows that there seems to be an environmental influence over what we find attractive. It is important to understand attraction, as your choice of partner is a very important decision - for your own sake and for the sake of your offspring."
Source: news.bbc.co.uk 13 June 2007
For articles on affair motivators, changing relationships, do-it-yourself psychotherapy, lies, insincerity, social graces, cosmetic surgery, roots of culture, self-deception, love,
and reunions of lost relatives click the "Up" button below to take you to the Table of Contents for this Relationships section.