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…”


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