Do beauties inspire higher sperm counts?

Posted in news by jenapincott on July 24, 2009

HughHefner Not all orgasms are created equal. For instance, intercourse orgasms are known to trump masturbatory ones, as evidenced by the amount of dopamine and prolactin produced. For men, sexual excitement produces higher sperm counts. As I recount in BLONDES, men who felt jealous or threatened by the possibility of a cheating partner had higher sperm counts than men who did not. The same is also true of male porn-watchers masturbating to a threesome. When guys watched two men attending to one woman, they had higher sperm counts than when watching one-on-one sex.

Sperm competition is the reason, according to the notorious British biologists Baker & Bellis. Men produce more copious, higher quality semen in situations in which those sperm might compete with rival sperm from other males.

And now there’s more — speculation that beautiful women also inspire men to have better quality sperm.

Female beauty has been found to enhance male sperm quality in other species. The latest evidence comes from a study led by Oxford biologist Charlie Cornwallis on Gallus gallus, a species of bird. Cornwallis and his colleagues discovered that the comelier the chick — e.g., plump with an elaborate comb — the better the quality her partner’s sperm (more motile, higher velocity, with a higher sperm count). Interestingly, this was true of dominant males but not subordinate ones, who appeared to put everything they had into every copulation. From Cornwallis’ perspective, the most fit males invest their best loads in the most reproductively fit females.

No study has yet proven that the same is true in humans — it’s not exactly ethical to recruit a guy to have sex with both a beauty and a plain Jane and then compare the aftermath. A beauty bias that affects sperm count may be true only in a wildly polygamous species, which humans are not.

Even so, this theory applied to humans doesn’t sound so controversial if you think about it — after all, sperm counts in men are associated with sexual excitement. Beauty can spark frisson. Even more exciting to ponder is how in practice an alpha male would make a larger reproductive investment in the most desirable mate. How does a Hugh Hefner decide? And wouldn’t it be ironic if this were true?

PsyBlog Top 40

Posted in media by jenapincott on July 22, 2009

psyblog_logoPsyBlog, a superb psychology blog in its own right, named this blog as one of the “40 Superb Psychology Blogs.” Click here to see the others on the list. Thank you, Psyblog!

Blatant works best when picking up men

Posted in news by jenapincott on July 21, 2009

l35b631350000_1_9129 In BLONDES I wrote about the pick-up lines men use to strike up conversation with women. Direct compliments were bad, sexual come-ons worse. The most effective lines involved those that suggested social status (“This drink’s on me; I know the owner.”) and kindness (“Let me help you get to the front of the line”) or culture and wealth (“I like your Versace sunglasses. I’ve got a pair too.”)

But given that women also approach men, what pick-up lines should women use?

The answer is direct no-nonsense lines, according to a recent study led by Joel Wade at Bucknell University. Wade and his colleagues asked 40 female undergrads which lines they’d use to pick up a guy, and how likely they’d use those lines in a real-life situation. More than 30 men were than asked to evaluate the lines.

The results:

“Hey, want to meet up later tonight?”
“Do you have a girlfriend?”
“I like your hair”
“Give me a call – here’s my number”

trumped the more subtle
“Hello, how’s it going?”
“Hey, what’s your name?”
“How was your weekend?”

and humorous/sexual comments (e.g. “Your shirt matches my bed spread, basically you belong in my bed”).

The more direct, the better. One interpretation of these findings is that men have a distaste for subtlety. Studies show that men have an overestimation bias — they’re more likely to think a woman is interested in them even when she’s not — so any blatant reinforcement is welcome. A direct pick-up line also suggests a more sexually motivated woman. She wants you, not just a chat.

I find it odd that men weren’t more responsive to direct sexual/humorous come-ons by women; I suspect it depends on the context and delivery. (The sample lines in the study were also real duds.) Or it supports the theory that many men don’t prefer sexually aggressive women. Even if a woman makes the first foray, men like a pursuit.

All this leads me to point to the limitations of studies such as this one. Men were asked to rate pick-up lines, but the effectiveness of the lines was not tested in an actual situation. See, guys are visual creatures; a direct pick-up line won’t work if they don’t find the woman attractive. And assuming the woman is comely enough, I suspect any come-on would work equally well.

Your right ovary rules

Posted in news by jenapincott on July 13, 2009

200028164-002cropIf you’re like most women you probably think ovulation is something of a meritocracy — that both ovaries do equal work, and that they alternate every cycle.

If by chance you were not taught that the ovaries soldier on left-right-left-right, then you probably think ovulation is random, like a coin toss.

The second scenario is closer to the truth, but it’s not the whole truth. At least not all the time or for most women.

Fact is, your right ovary is likelier to ovulate more often than the left. This means that in two consecutive months, the right side is probably the one doing more of the hard work of producing the dominant follicle that could become a baby.

At least this is what multiple studies have found, including here (57.7% of women have right-side ovulation), here (54.5 percent have right-side ovulation), and here (62% of total follicles are on the right), and here (larger, more numerous follicles).

Why is the right ovary often dominant?

Anatomical asymmetries between the left and right sides are thought to be the reason. The left ovarian vein drains to the left renal vein and the right ovarian vein to the inferior vena cava. The left renal vein is thought to be under higher pressure than the right and therefore drains slower. Because the left ovary drains slower, the collapsed follicle (called a corpus luteum) takes longer to clear and thereby diminishes the chance that ovulation will occur on that side the following month. No such condition exists on the right side, which is why successive right-side ovulation is more common. Estradiol and testosterone levels are also higher during a right-side cycle; this may also be related to the right ovary’s more efficient plumbing as it flushes lining-plumping hormones into the uterus.

All this leads to some fascinating statistics. For instance, right-sided ovulation favors pregnancy more often than left-sided ovulation (64 percent of pregnancies came from women’s right ovaries), according to a study in Japan that tracked nearly 2,700 natural cycles. Then again, according to another study, odds of pregnancy are best when the dominant follicle develops in the ovary opposite to where ovulation took place in the previous cycle (with pregnancy occurring more often in a right-side cycle that follows a left-side cycle) because the dominant follicles in such cycles are healthier. Even if the right ovary drains faster than the left, the corpus luteum left over from the previous cycle still negatively affects the hormonal health of the dominant follicle. Best to start with a clean slate.

Interestingly, researchers in another study speculate that right-side ovulation is dominant for most of a women’s reproductive years. Toward perimenopause women are more likely to become left-dominant, presumably because the supply of follicles in the right ovary has diminished.

Apart from ultrasound, there’s no reliable way of telling which ovary you’re ovulating from. ( I devote a section of BLONDES to why ovulation is concealed, even to women themselves.) If you think about it, perhaps that’s a good thing.

What body region are you judged by most?

Posted in news by jenapincott on July 8, 2009

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Which do people fixate on most when assessing women’s physical attractiveness — the stomach or the hips?

As I discuss in BLONDES, weight, as estimated by body mass index (BMI), and curves, as measured by waist-to-hip ratio (WHR), are two major factors when assessing women’s bodily attractiveness. Which matters more is a point of contention between various experts.

A new study led by University of York psychologist Piers Cornelissen tries to settle the argument. Implementing a novel way of tracking eye movements, Cornelissen asked male and female volunteers to rate nearly 50 photos of women. The longer their gaze rested on a particular body region, the more that region counted.

There’s a strong argument that curves should matter more than weight when evaluating attractiveness. A low WHR — a relatively thin waist to hip ratio — suggests something about a woman’s hormonal status. Estrogen increases the deposition of body fat on the hips thighs, and bust. Higher estrogen is linked with higher fertility.

But those aren’t the body regions that people fixate on when they look at you, according to Cornellisen’s experiment. The stomach apparently has the most impact. When judging attractiveness, both sexes appear to settle their gaze on the central torso, an area that reveals much about a person’s overall body mass, and not the pelvic and hip areas. This outcome, according to the psychologists, suggests that body mass index is more important in assessing physical attractiveness than curviness.

The study is not conclusive. It’s possible that WHR is assessed more quickly than body mass, which could be why people fixate longer on the torso. Or perhaps the study participants, aware that their eye movements are tracked, are abashed to linger on the pelvic region of the models. The central torso is also quite close to the bust.

Still, it’s another study that falls definitively in the body mass-over-curves camp. And perhaps it helps explain the new rage in stomach-cinchers.

“Blondes” in The Daily

Posted in media by jenapincott on

daily-masthead
Nice mention of BLONDES in The University of Washington’s The Daily .
Too jet-lagged to write more today. Back to regular posts soon.

Banned in China

Posted in media by jenapincott on July 6, 2009

banned_mediumI tried but could not access/ update this blog anywhere in China this past week. Apparently, the Chinese internet filters find it censor-worthy.

Nocturnal orgasms — women have them too

Posted in news, Polls and Surveys by jenapincott on June 25, 2009

For the 40 percent of women who’ve had one, an orgasm in a dream is often more intense that one in real life. And it’s not just a dream — a nocturnal orgasm is a real physiological phenomenon. The dreamer awakens to the same pulsing sensations she’d have during an orgasm from masturbation or sex. Her heart rate surges, her breathing deepens, her vaginal blood flow increases. Her orgasm might even be so fierce that she cramps up as she transitions from dream to reality.

Why?

A few studies shed some light:

1. During REM, the relative pulse pressure in the vagina increases. This also happens to a man’s penis, resulting in nocturnal emissions and morning erections. The content of the dream doesn’t appear to affect genital pulse — after all, it increases every time you sleep — but the physical sensation may influence your dreams (no one knows for sure). At the same time, the parts of the brain that inhibit orgasm, particularity the prefrontal cortex and amygdala, are offline when you’re asleep. (Readers of BLONDES might recall that the left amygdala, associated with anxiety, and the prefrontal correct are quiet during orgasm.)

2. Female orgasm can result from brain activity alone — “no hands.” Evidence of this comes from the research of Beverley Whipple, who studied women who reach orgasm via “self-induced imagery” (i.e. fantasy) alone. Volunteers’ blood pressure, heart rate, pupil size, pain threshold, and so on increase as they reach climax, their hands nowhere near their genitals.

As speculated by Whipple ( see also her research on paralyzed women), a “hands-off” orgasm may channel the vagus nerve, which is like a livewire that extends from the brain to the cervix via the heart, lungs, and other organs. Not every orgasm strums it — but, like hitting the right chord, a vagus nerve climax is said to be richer and more fulfilling. Some women think they can even feel it surge through their bodies from their brainstems. (See previous blog about asphyxiophiliacs.) It’s interesting: Vagus nerve activity might be one reason why so many women say their nocturnal orgasms are so much stronger than their diurnal ones.

Only in their dreams….

Height isn’t everything

Posted in news by jenapincott on June 21, 2009

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Two inflammatory points in BLONDES are:

1. Women tend to have a same-race bias in marriage. This is especially true of black women — at least in the US and UK. Asian women have the weakest same-race bias. Asian men, meanwhile, seldom marry women of other races.

2. Short men get short shift. Women prefer men who are taller and men prefer women who are shorter.

A new economic research paper, Anthropometry of Love: Height and Gender Asymmetries in Interethnic Marriages, led by an Oxford economist, combines these two findings. The latter (#2) explains the former (#1), they claim. Height is a major factor, which means the reason Asian men don’t fare as well in the interracial marriage market is they tend to be shorter than men of other races while Asian women have more options for the same reason. Black women, meanwhile, tend to be taller of women of other races, so they fewer options. (See discussion in the Times.)

We argue that a simple preference for a taller husband (or shorter wife) can explain part of the gender-specifi…c asymmetries across ethnic groups in the propensity to outmarry. Blacks are taller than Asians, and their height distribution is closer to whites. Because they are taller, black men have better prospects on the white marriage market than Asian men. For women, the reverse is true. Because Asians are relatively short on average, women fare substantially better on the white marriage market than black women.

There’s a certain (uncomfortable) logic to this, but height shouldn’t overshadow more important factors.

The economists ignore findings that many people tend to marry those from a similar background (religion, educational level, and ethnicity including race), because familiar trumps foreign in a long-term context. (Happily, certain behaviors such as talking about a favorite literary work reduced same-race preferences in one speed-dating study). While height may well be a deciding factor in selecting a long-term partner, a shared background is likely stronger. (Many non-Asian women believe Asian men are more traditional and would not marry them.)

Also overlooked by the economists are the other qualities that matter to women: status, paternal proclivity, and resources. Like background, these qualities may be more influential than height. Women are inclined to overcome their same-race and height biases when a man has an abundance of one of more of these qualities (according to studies I describe in the the book). This suggests that a short guy of any race will have more marriage options, including a tall choosy black woman, if he’s successful, kid-loving, and shares a lot in common with that woman.

Note to economists: height is important to sexual selection — but it isn’t the only measure.

Ma perchè gli uomini preferiscono le bionde?

Posted in media by jenapincott on

8845414787g BLONDES just debuted in Italian, illumina il mistero più appassionante: l’amore.

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