Category: news

“Cheating gene” mouth swab test available

Posted in news by jenapincott on May 8, 2010

In BLONDES and in this post I write about the so-called “cheating gene.”

Not long ago, Hasse Walum, a handsome post-graduate at the Karolinska Institute in Sweden, decided to study the association between a particular gene for what is called a vasopressin receptor and relationship stability. He analyzed the responses of over 550 twins and their partners to questions, some of them intrusive, about their relationships: How often do you kiss your mate? “Have you ever regretted getting married/moving in?” “Have you discussed a divorce or separation with a close friend?” “Rate your degree of happiness in your relationship on a scale of 1-7.”

Walum then sampled the men’s DNA. Getting DNA from the men was simple. You don’t need blood to have access to another person’s genome, just saliva, which the men submitted in a mouth swab.

What Walum discovered was stunning. Focusing on one particular vasopressin receptor gene variant, allele 334, he found that the more copies of it a man had, the weaker his bond with his partner. Men who lacked the gene variant were generally happiest in their relationships — only 15 percent of them had a crisis. Men with one copy were slightly more likely to have marital problems. And men with two copies were, on average, twice as likely to have had a relationship crisis in the past year than men who didn’t have the variant — meaning that 34 percent of them, or one in three, were headed toward a break up. Their partners agreed. Women whose partners carried one or two copies of the allele 334 variant were generally less satisfied with their men, probably because they generally scored as less affectionate than other guys.

Walum also found that men with two copies of the variant were nearly twice as likely not to marry their partners and mothers of their children as men who had no copies of the variant. This suggests that there is something slightly different about the vasopressin receptors in the brains of men who struggle in their roles as partners and fathers. These men may have more difficulty bonding with other people, including their wives and kids.

I imagine that some of you are now scheming to get an allele 334 test for your man. Of the more than five hundred women who responded to my online poll on this topic, nearly 65 percent said they would test their man if given the option.

And now you can. Yes, you can order a saliva test for allele 334 of the AVPR1A gene for $99 from Genesis Biolabs. (I can’t vouch for the lab. I’m reporting for entertainment purposes.)

Ladies, there’s a caveat here, of course. Even if there’s a correlation between this particular gene variant and a man’s behavior, it doesn’t account for all men. Just as the “god gene” and “gay gene” are met with skepticism in the scientific community, so is the “cheating gene.” Even within Walum’s study, there were men with two allele 334 variants who were happy husbands and fathers, and there were men without the variant who were miserable in their relationships. The statistics apply to populations, not individuals, who are also influenced by a other factors — parental role models, partner choice, opportunity to cheat, past loves, age, life satisfaction, religion, hormone levels, and so on.

A two-allele man may become a number one husband under the right circumstances.

But it’s your call. Swab him and then decide?

A new theory on men’s penis shape?

Posted in news by jenapincott on April 27, 2010

Several months ago, I blogged about a new theory on why men love breasts. New theories pop up all the time, so it’s no surprise that there are new theories on male body parts, too. A recent issue of Archives of Sexual Behavior features an alternative explanation for the shape of the human penis.

As described in BLONDES, the prevailing theory on why the human penis has a distinctive head and corona (rounded projecting border) is that it can scoop out semen deposited in the vagina by a woman’s previous lovers, thus averting a pregnancy. This means the last lover, not the first, gets the head-start.

Not likely, says Dr. Edwin Bowman, in his letter to the editor.

Instead of scooping out other men’s semen, writes Bowman, the penile head and corona scoop out vaginal secretions. After collected, these fluids are then absorbed by the foreskin. The mucous membrane of the foreskin, it turns out, is like a sponge for the stuff.

Why would evolution select for men to absorb vaginal secretions?

Just as semen has “mind control properties,” so do vaginal fluids. When ovulating and most likely to conceive, these secretions contain neurohormones such as pitocin and vasopressin. The latter in particular has been associated with bonding and is thought to trigger protective behavior among males for their partners. Vasopressin, after all, is thought of as a male “love drug.” Flooded with bonding hormones, a guy may be more likely to stick around if he impregnates his partner.

Knowing this, will more men use condoms?

Pourquoi les hommes préfèrent les blondes

Posted in news by jenapincott on April 16, 2010

Now in French. Note the title is no longer posed as a question!

Why pregnant women are calmer

Posted in news, pregnancy by jenapincott on March 30, 2010

If you were to take the Trier Social Stress Test (TSST), as nearly one hundred fifty pregnant women did in a study led by Sonja Entinger at the University of California at Irvine, you’d be led to a windowless room with a video camera and instruments that measure your vital signs. There, an assistant would ask you to sit and be hooked up to instruments that measure your vital signs. In the room you’d also find three men and women sitting at a table, waiting for you.

They are your interview panel.

Facing them belly-on, your instructions are to pretend that you’re applying for a job and must deliver a five-minute speech to convince them that you’re right for the position. Someone would say 1-2-3-GO, and you’d start babbling, hopefully coherently. If you have nothing more to say before your time is up, one of your interviewers will blandly instruct you to continue. Run out of words again and twenty seconds of eerie silence will fill the room. And when you’re finally done, you’ll be asked to do a bit of mental math — say, to count down, in increments of thirteen, from a large prime number like 54,499. Before and afterward the fifteen minute ordeal, a researcher will enter the room and hand you a swab to collect your saliva for testing.

Analyzing all the data from their study, including an analysis of body language and hormone levels of women who took the TSST, the UC Irvine researchers confirmed something remarkable: the further along a woman was in her pregnancy, the less stressful she found the stress test. Compared to their stress levels in second trimester (17 weeks), volunteers in their third trimester (31 weeks) had lower blood pressure, slower heartrates, and lesser spike in the hormone cortisol. Pregnant women also did not stress out as much as nonpregnant controls who took the same tests at the same time intervals. This was not the first study that found that pregnant women, especially those in third trimester, are calmer than nonpregnant women under the same (short and moderately stressful) circumstances. But it was the first time that the same women were tracked at different stages of gestation.

So what is that makes pregnant women more Zen as they approach their due date? The likely answer is that the body reduces the sensitivity of cortisol receptors, even though baseline levels of the stress hormone are higher. In other words, it takes more stress hormones than usual to get the nervous system all hot and bothered. At the same time, the placenta increases production of an enzyme that changes cortisol to an inactive form, meaning that less of the toxic stuff filters through to the baby. Near the end of pregnancy, probably to calm you down before labor and help you bond with the baby, your body also produces more of the nervous-system soothing hormones oxytocin and prolactin.

All this is good news for moms who are slammed with short-term mild to moderate stress late in their pregnancies.

But there’s an even bigger surprise to come out of this. You may think this is your body subconsciously protecting the baby at a time of stress. But it’s just as likely that it works the other way around: your baby protecting you (as well as herself), because her placenta is responsible for at least some of the stress-dampening response to cortisol. It’s a beautiful idea — mother and child soothing one another in the face of life’s assaults.

WSJ Saturday Essay

Posted in magazine articles, media, news by jenapincott on March 27, 2010

Here’s a link to my essay in today’s Wall Street Journal. To attract attention, the WSJ gave it a lightning-rod title: “Why Women Don’t Go For Macho Men.” Men, please stop sending me hate mail! My article — and the study on which it is based — are more nuanced.

(The print edition has the title “The Masculine Mystique,” which inspires an entirely different response.)

Men prefer dark nipples?

Posted in news by jenapincott on March 14, 2010

Thank goodness Victoria University’s $60,000 “Eyelink 1000” eye-tracking device was available recently to psychology PhD student Barnaby Dixson, for now we have more clarity on what, exactly, men think of women’s breasts.

Dixson recruited men to look at images of naked images of women that were digitally altered to increase or decrease the size of her bust and the color of her areola (the ring around the nipples). In keeping with evolutionary theory and previous experiments on men’s breast size preferences, Dixson hypothesized that guys would gaze longer at larger breasts and prefer light areolae. Fair to light pigmented areolae and nipples would be considered sexier, he reasoned, because these hormonally-sensitive features darken with pregnancy and with age. He also asked the guys to rate the attractiveness of each photo.

But the results weren’t exactly as expected.

Turns out that men did indeed rate women with medium-sized and large breasts as more attractive than women with small breasts. But variation in breast size did not affect their eye movements — they were just as likely to fixate on small breasts as large ones, and for the same number of times.

And the nipple data was even more shocking. The first thing men fixed their gaze on was women’s areolae. And while they fixed their gaze just as often and as long on pale nipples as dark ones, the majority expressed a distinct preference for dark areolae. Dark nipples appear to play a significant role in men’s judgments of women’s attractiveness.

Like large breasts, Dixson reasoned, dark areolae suggest sexual maturity. Yes, older and pregnant women have darker nipples than younger women, but those pigment changes also come from hormones that suggest fertility — high levels of estrogen and progesterone.

Is a successful line of nipple and areolae blush in this PhD student’s future?

Even blind men prefer curves

Posted in news by jenapincott on March 8, 2010

When traveling around the world, even to the remotest regions, anthropologists have often carried with them illustrations of the female figure. Some of the women represented have thick waists, what is known as a high waist-to-hip ratio, or WHR. Others have tiny wasp waists, a low WHR. Some have WHRs somewhere in between. The anthropologist will show these drawings to the menfolk, and ask them which figure they prefer.

About 90 percent of the time, men prefer women with a WHR of about .7, the waist being 70 percent the width of the hips, which is rather low. Some cultures prefer heavier women and other cultures prefer lightweights, but the preferred proportions are about the same.

For decades researchers have debated the importance and veracity of these findings. As detailed in BLONDES, many researchers think there are some very good reasons why men prefer wider hips and smaller waists: fertility (wider pelvises are good for childbirth and high estrogen prevents excess waist waste), sexual dimorphism (it’s what makes women “womenly”), youth (the exception being wasp-waist-record-holder Cathie Jung, above, who modified hers), and health (the fat that accumulates on the thighs is good for a baby’s developing brain, while abdominal fat is harmful).

These are all good reasons. But naysayers claim that Western culture has influenced the rest of the world through TV and other media, which is why men prefer such small waists in proportion to hips. These critics believe that the preference is the result of visual learning. Kids grow up seeing that women with low WHRs are considered most attractive, and they believe it. This is reinforced by the Western media. Drawing on this logic, these skeptics think there is nothing intrinsically sexy about curves.

But now a score for evolutionary psychologists.

A recent study led by researchers at Rahboud University in the Netherlands and the University of California at Los Angeles confirmed that men prefer small-waisted women — by sight or by touch. Nearly forty men, half of them blind from birth, were invited to a lab containing mannequins. One mannequin had a figure with a 70 percent WHR, often considered the golden ideal, while the other had a thicker 84 percent WHR. The men were asked to rate the attractiveness of each figure. Sighted men gazed and blind men groped. Later, reviewing the results, the researchers saw the same clearcut pattern: both groups rated the hourglass-shaped mannequin as sexier. (Vision did play some role, with the sighted group giving the slimmer-waisted mannequin higher ratings, but the difference was slight.)

No doubt cultural relativists will refute this, saying that the sightless are also influenced by Western media. Blind guys might not see shapely female bodies, but they’ll hear about them and form a bias in their favor. In the immortal words of singer Sir Mix-a-Lot: “I like big butts and I can not lie/You other brothers can’t deny/That when a girl walks in with an itty bitty waist/And a round thing in your face…”

How a hot partner makes you seem hotter

Posted in news by jenapincott on February 28, 2010

Ask a veteran E-Harmony or user to list her peeves about online dating, and she’ll surely mention the “cropped-ex shot.” Why do so many people include pictures of themselves with seemingly unattached body parts — a slim bangled arm thrown around their shoulder, or hairy fingers around their waist? Those body parts, assumed to belong to an ex, are maddening in part because of what they don’t reveal: the ex herself (or himself).

That’s because we rate another person’s attractiveness, at least in part, on the attractiveness of his or her partner.

Researchers call this mate-choice copying. As I detail in BLONDES, mate-choice copying happens in many animal species, and there’s mounting evidence that human animals are no exception. If that male has an attractive partner, then there must be something worthwhile about him. It’s a wisdom-of-crowds approach.

The latest mate-copying study, published by researchers at Duke University and the University of California Davis, involves 30 male and 30 female volunteers who all described themselves as straight. One group of volunteers was then asked to rate the attractiveness of men and women pictured alone in photos. Another group was then shown pictures of the same men and women paired together and asked how desirable they would find long-term relationships with members of the opposite sex in the pictures. They were told the people in each photograph had been engaged in a long-term romantic relationship but their relationship ended.

These exes were not cropped out.

No surprise to evolutionary psychologists: Both male and female volunteers rated people in the pictures as more desirable when they were paired next to attractive companions than when they were pictured alone. This was true for both men and women. By using cameras to track eye movements during the experiments, the researchers also saw that when volunteers spent more time looking at a potential mate’s unattractive partner, they were less interested in that mate. Interestingly, even though judges were only asked to rate the person of the opposite-sex, they all spent significant time looking at that person’s partner. Having a homely ex can hurt you.

The exception, the researchers found, is if you’re a hot woman. While women downgraded otherwise hot men if they were paired with a dumpy partner, men gave high ratings to the most attractive women regardless of their partners. As found in other studies, women, generally the choosier and more cautious sex, are more likely to rely on social cues such as whether other women find the target guy attractive.

By no means does this warrant that you leave your ex, in full or in part, in your profile photo. Unless your ex is your only asset.

Are firstborns likelier to marry firstborns?

Posted in news, Polls and Surveys by jenapincott on February 20, 2010

Opposites attract, but not in marriages or other long-term relationships. As I describe in BLONDES, we value in others what we value in ourselves. So many of us prefer those with similar background, religion, ethnicity, education, values, and so on. Women often prefer potential spouses who look like themselves or family members. We even prefer those whose body language and verbal intonation resembles our own.

The marriage-minded seek the like-minded.

So is it any wonder that researchers have now found evidence that birth order — one of the major forces that influences who we are — also influences our choice in marriage?

In a recent study, Harvard researcher Joshua Hartshone and his colleagues found evidence that people are more likely to form long-term romantic relationships with someone of the same birth order rank. Only children are likelier to marry other onlies, firstborns are likelier to marry firstborns, middleborns are likelier to marry middleborns, and lastborns are likelier to marry lastborns.

The study, based on the responses of over 2,500 visitors to the website, found that the birth-order effects are independent of family size and unlikely to be a product of class or ethnicity. “If spouses correlate on personality,” Hartshone writes, “and personality correlates with birth order, spouses should correlate on birth order.”

Incidentally, the researchers found that best friends also tend to share the same birth order.

My parents are both firstborns. Many of my closest friends are onlies and firstborns who married other onlies and firstborns respectively. Me, I’m a firstborn who married a middleborn.


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