by Andrew Trees
FICKLENESS, THY NAME IS FERTILITY CYCLE
It is possible that the chemistry of the body, particularly hormones, also offers an explanation for the fickleness attributed to women. For example, a woman’s ovulation cycle can have a dramatic effect on what sort of man she finds attractive. Studies have shown that during ovulation women find masculine faces more attractive but find feminine faces more attractive the rest of the time (other traits such as voice follow a similar pattern). Women during ovulation also show a greater preference for the smell of symmetrical men. Masculine faces and symmetricality are signs of health, so there are very good evolutionary reasons why women would have developed an unconscious preference for these markers of genetic superiority. Intriguingly, women do not show a preference for the smell of symmetrical men when they are not ovulating. This may be due to the unconscious realization that men with the best genes often don’t make the most faithful partners, which suggests just how subtle our evolutionary tendencies can be. Even the smell of other women can influence female behavior. In one study, women exposed to the smell of other women who were breast-feeding found that their sexual desire spiked 17-24 percent. Truly bold women can try to pull off a daring stunt with their copulins, which are fatty acids found in vaginal secretions. In one study, while men did not rate the smell of copulins as pleasant, they had a dramatic effect on how the men viewed women. After being exposed to the smell, the men gave higher ratings for attractiveness to photos of women, and their testosterone levels spiked. The less attractive the woman, the more her rating went up. If men want to pull off a similar feat, they can try to plant some sweat under a woman’s nose. In one study, women rated men’s faces and then were exposed to a small amount of underarm sweat and asked to rate the faces again. After smelling the sweat, the women raised their ratings substantially.
It’s not simply how we judge looks that can be affected by things like smell and ovulation—these things can also alter what sort of personality a woman finds attractive. In a study run by Geoffrey Miller and Martie Haselton, women read stories that described either a creative, poor man or an uncreative, rich man. When women were near their peak fertility, they preferred creativity to wealth for a short-term relationship, offering evidence that ovulation can dramatically affect a woman’s mate choice by pushing her to choose good genes over a good dad, particularly when she is not making a long-term decision. Marriage itself influences a woman’s preferences. In another examination of the influence of smell on female choice, a woman with a partner preferred the smell of more dominant men, while single women showed no preference. Researchers have suggested that single women were interested in securing a partner, but once that was taken care of, women turned to the pursuit of the best genes. Ovulation may even provide an explanation for the female complaint that all the good men are taken. According to a 2008 study, women with partners found men in a relationship more attractive during periods of low fertility, but they preferred single men (if they displayed masculine traits) during periods of high fertility. Again, this shift in preference seems to correspond to a good genes/good dad split, with ovulation increasing a woman’s attraction to single, masculine men for their genes but with low fertility shifting their attraction to men who show an ability to commit to a long-term relationship (i.e., a man already in a relationship). So, the next time a woman finds herself lamenting the lack of available men, she can perhaps blame it on her fertility cycle.
MEN GET MOODY, TOO
Don’t worry, ladies. A man is ruled just as much by his own body chemistry, although it does not function in the same way that a woman’s does. Let’s return to that odiferous object of scientific inquiry, the sweaty T-shirt. Researchers decided to run a similar smell test on men. They gave women cotton T-shirts to wear during different phases of their menstrual cycle and then had men smell the results. What men honed in on was not a woman’s MHC profile but her ovulation cycle. Rating T-shirts for pleasantness and sexiness, men gave women who were ovulating or about to ovulate a much higher rating than women who were approaching menstruation. According to another study, women reported that their partners became more loving and attentive during their ovulations as well as more jealous of other men. In other words, men aren’t particularly focused on finding a woman with a different immune profile, but they have an uncanny ability to seek out women who are at their peak fertility. This seems to hold true in the real world as well as the experimental one. In one barroom study, men initiated touching with ovulating women more than nonovulating women. This all makes evolutionary sense. In general, men want to have sex with as many fertile women as possible, regardless of whether or not the woman is a good genetic fit. For women, though, each pregnancy represents a huge investment, so it makes sense that they would devote a lot more (unwitting) attention to ensure that the baby has the best genetic chance of success.
Men also have their own hormonal fluctuations to worry about. Their testosterone goes through a series of peaks and valleys throughout the day, but it can still serve as an indicator for more significant traits, such as mood and aggression. Some men are naturally low in testosterone, which is good for society because if all men were alpha males, the fighting would never stop. We would constantly find ourselves locked in Travis Bickle-like arguments. “Are you looking at me?” “No, but are you looking at me?” Important life changes can also influence a man’s testosterone. When men are in a stable relationship, their baseline level of testosterone drops. For example, married men have lower testosterone on average than single men, and married men with children have less testosterone on average than married men without children. But their testosterone will ratchet back up if the relationship becomes unstable. A high-testosterone man will also behave more aggressively when it comes to dating. A study was done in which different men competed for the attention of a woman. Men with high testosterone would make fun of the other man, criticize him, and refuse to laugh at his jokes. Women interested in a long-term relationship should try to avoid men who display the traits of someone with high testosterone—they tend to marry less frequently, have more affairs, abuse their wives more, and divorce more often.
STARRY-EYED OEDIPUS
In a result that will delight Freudians, it appears that although men may not want to sleep with their mothers, they do prefer women who remind them of their mothers—at least that’s what the evidence from the animal kingdom seems to suggest. In one study, the mothers of infant male rats were doused with lemon scent. Later, the males were paired with some female rats with lemon scent and some without it. It was no contest. The males mounted the lemon-scented rats sooner and ejaculated more quickly. One man I interviewed admitted that he had a serious relationship with a woman and found himself attracted to her perfume, only to realize later the rather distressing news that the perfume was the same one his mother used.
Luckily, we seem to have evolved mechanisms to protect us against our own personal Oedipal drama. One researcher decided to take a look at marriage on an Israeli kibbutz. Because of the way the kibbutzim is structured, girls and boys are raised in close proximity, almost like brothers and sisters of the same family. When researchers looked at their marriage patterns, it turned out that even though they would not have violated any incest taboos, children of the kibbutzim almost never married. Of the 2,769 marriages, only thirteen were between children who grew up together, and even in those cases, at least one of the children moved in after the age of six. So, it appears that the ultimate antiaphrodisiac is growing up from a young age in close proximity to one another.
Of course, if you want to maximize the number of children you have, there is a powerful incentive to choose someone in your extended family: greater fecundity. According to a study of the Icelandic population, the ideal degree of relatedness to produce the maximum number of children and grandchildren is a union between cousins of the third or fourth degree. Any closer and the couple risks inbreeding. Any further and the couple risks running into genetic incompatibility prob
lems. Who knew that extended family reunions are a potential dating scene?
YOUR CHEATING . . . GENE
It also appears that there may be a genetic component that determines how likely a man is to cheat, what some researchers have dubbed the “promiscuity gene.” They have found that there is a variant in some genes for the D4 receptor, a dopamine receptor. Because dopamine is the chemical that stimulates us to want things and underlies everything from sexual attraction to gambling addiction, a change in dopamine reception can have a major influence on our behavior. Men with the promiscuity version of the D4 receptor have an increased desire for erotic adventure and have 20 percent more sexual partners than the average man. Researchers estimate that roughly 30 percent of men carry this gene, but before women go on a genetic witch hunt to weed out these philandering miscreants, they should know that, while similar research has not been done on women, it is very likely that some women have a similar genetic variation. Remember—all those children who are not the product of their legal parents’ loins need both a cheating father and a cheating mother.
For a more precise take on a man’s ability—or inability, if you are a glass-half-empty kind of gal—to be faithful, we need to take a look at the rather unprepossessing and very monogamous prairie vole. Upon reaching maturity, the male latches onto virtually the first available female partner. The couple will spend an entire day copulating like, well, voles and then spend the rest of their lives together. Even separation does not change the bond, and when one of the partners dies, the other vole, in a remarkable display of fidelity, does not take a new mate. However, there is another type of mole—the montane vole—which is polygamous.
So, what accounts for the unstinting and admirable monogamy of the prairie vole and the promiscuous polygamy of his montane cousin? It probably all comes down to one small slice of DNA that acts as a blueprint for a particular type of vasopressin receptor in the brain, and the reason that receptor is so important is that the hormone vasopressin, which is released during sex, plays a central role for males in forming monogamous bonds. The prairie voles have this slice of genetic code, which means that they have a lot more vasopressin receptors in their brain than the montane voles. That makes them much more susceptible to the pair-bonding power of vasopressin. When scientists inserted this genetic code into montane voles, they immediately became as monogamous as the prairie voles.
Vasopressin is so powerful that prairie voles don’t even need the sex to form a monogamous bond. They just need the vasopressin. If injected with it, they form a lifelong bond with the first available female, even though they have not had sex. When the vasopressin is blocked, the male vole acts as if he has never seen the female before, even after having repeated sex with her. How many women know that feeling? Vasopressin (and oxytocin for the females) has even been used to create monogamy among polygamous house mice. In a final twist, it turns out that all voles are not created equal when it comes to vasopressin. Further study revealed that some males have a longer version of the gene than others and that those with the longest versions are also the most reliable partners.
So, what sort of vasopressin receptors are men equipped with? The answer is far more complicated than anyone first imagined. Researchers have already found that the human version of the gene comes in at least seventeen different lengths, a number that is likely to grow as more work is done (similar work also needs to be done for women and oxytocin). What this means is that there is a wide spectrum of possibilities when it comes to the issue of how genetically predisposed individual men may be toward monogamy. Still, it may hold the key to understanding long-term bonds between men and women. To give you some idea of how significant this particular gene might be to male behavior, a shorter version of the gene has been found in those with autism, a condition characterized by difficulty forming relationships with other people. As men realize the possible seductive power of their receptivity to vasopressin, we may one day find that they have stopped bragging about the size of their members in order to brag about the size of their vasopressin receptors, which would, I think, have to be considered at least a small step forward.
Of course, any definitive answers to the chemical nature of love are still a distant hope, but scientists are making progress. As we have seen, researchers have been able to sniff out at least a few clues about the elusive nature of attraction between a man and a woman. If all else fails in your search for love, remember that you can always simply follow your nose.
A Second Brief Intermission to Focus—Finally—On the More Traditional Subject of a Book About Attraction: Practical Advice
THE REAL QUESTION IS, CAN SCIENCE PROVIDE PRACTICAL advice for all of us wayward daters? The surprising answer is yes. Some of that advice is common sense, and some of it is unexpected. Before I go into any of it, though, I want to issue a warning. I have read far more dating books than any human being should, and they have convinced me of one thing: be leery of anyone who confidently offers surefire dating tips. Most of these books are based on little more than a mishmash of anecdotes. I can promise that the information in this section is based on the same scientific studies and surveys as the rest of the book. That said, please treat what you are about to read as a casual buffet of dating tips from which you can pick and choose as you please.
I’ve broken this part into three sections:
1. For Him and Her;
2. For Him;
3. For Her.
FOR HIM AND HER
Learn to love yourself. I know that sounds incredibly unscientific and touchy-feely—I can almost hear strains of “Kumbaya” in the background—but a great deal of research backs it up. Simply put, the more you have a positive view of yourself, the more likely you are to fall in love. And the more likely the love will be healthful, rather than destructive.
Although we like to believe we aren’t shallow people who simply judge a book by its cover, research shows that first impressions are very important. According to a 1993 study, people viewing a videotape of a teacher were able, after viewing the tape for only thirty seconds, to do a very good job of predicting how a teacher would be evaluated by his or her students. And here’s the real kicker: the thirty seconds included only nonverbal interaction and physical attractiveness. If you are unsure how to make a good first impression, there are many books that have been written on the subject, although I have one suggestion: focus on the other person. A good first impression depends more on showing interest in someone than in showing off.
Selective desire is better than generalized desire—in other words, don’t hit on every eligible person you meet like some kind of Energizer bunny of flirting. In a recent study, people who were seen as having generalized desire were perceived as less desirable, while people who showed desire for just one person were viewed much more positively. Also, in a study of speed dating, researchers found that the choosier people were, the higher others rated their appeal.
Try to bump into the object of your desire as often as possible. Familiarity has a powerful effect on attractiveness. In one study, men and women were shown a number of photographs and were asked to select the photograph of a person they could imagine marrying. Afterward, some of the photographs were projected several times on a screen, and then the participants were asked to select a photograph again. In a number of cases, both men and women changed their initial selection and switched to one of the photographs that had been projected several times. The other benefit of this for the less attractive among us is that physical attractiveness becomes less important over time as what researchers call the “familiarity effect” takes hold.
Keep your face animated—although not so animated that you come across as crazy. Research shows that a face animated with expression is seen as more attractive than one that is devoid of emotion. This is why people with good poker faces have trouble getting dates.
Use eye contact. We’ve already discussed this, but I can’t emphasize enough how powerful this is. Eye contact can boost attractivene
ss, regardless of the sex. In a study conducted by psychologist Arthur Aron, total strangers were paired up and had a ninety-minute conversation in which they shared personal details about themselves. Then they gazed silently into each other’s eyes for four minutes. Afterward, they were asked about their feelings for the other person, and many of the participants admitted that they felt strongly attracted. How strongly? Some of the couples eventually married! Not bad for four minutes of eye contact.
Don’t obsess about how you look. Obsess about how you act. A recent study showed that while attractiveness, emotional expressiveness, and social skills all contributed to someone’s likability, attractiveness was the least important of the three.
If you aren’t attractive, at least try to hang out with attractive people. A study found that people sitting next to attractive people were also judged to be more attractive because of their proximity.
Show the person that you like him or her. Researchers have discovered that how much we think someone likes us has a powerful effect on how much we like them. I realize that it is somewhat disheartening to consider that we have not evolved much beyond junior high school when serious flirting involved passing a note telling someone that you liked them and asking them to check a box if they liked you, but it’s true. Studies have found, for example, that a similarity in attitudes has far less of an influence over how much someone likes you than does reciprocity (the feeling that both people like each other). And once both people are convinced that the other person does like them, it can create a positive feedback loop where increasingly positive feelings are created.