Does “stress sweat” make you more compassionate?

Posted in news by jenapincott on August 4, 2009

armpit3Pheromones fascinate me, and not only the ones that mediate sexual attraction.

Several months ago I wrote a post about a study that suggests that airborne chemical signals also mediate stress and fear. Known as alarm pheromones, these chemicals are found in sweat and saliva. In that experiment, sweat from skydivers (collected from pads in their armpits) activated anxiety circuits in the brains of people who sniffed those pads later on. The fascinating theory: Emotions can be communicated by smell. It happens unconsciously.

That was just one study, and naysayers are quick to point out that a solitary experiment doth not prove human pheromones are real. But now there’s further proof.

Researchers at the Universities of Dusseldorf and Kiel in Germany recently published the results of study based on the sweat smells of 49 stressed-out students after a.) taking a final oral exam (stress sweat) and b.) exercising (sport sweat). Sniffing the pads that had been in students’ armpits, volunteers often couldn’t detect an actual odor. Nor could they tell whether they were smelling stress sweat and sport sweat. But it turns out that an area of their brains detected the difference. Only stress sweat — and not sport sweat — triggered brain activity in areas involved in the processing of social emotional stimuli (fusiform gyrus), and empathetic feelings (insula), attention (thalamus).

The implications are fascinating. Is stress contagious? In an emergency situation, it makes sense that we’re “wired” to perceive and respond to the stress of others. An odor that induces attention and anxiety may help a group to focus together or synchronize a fight-or-flight response.

It’s particularly interesting that neural circuits associated with empathy — not just attention — were activated. Are we naturally empathetic creatures? Then again, there’s no proof that the volunteers actually felt more understanding and compassionate when smelling stress sweat even if their brains go through some of the motions. I suspect empathy is context-dependent. Further experiments should look into whether volunteers really are more empathetic (more willing to help a person in distress, for instance) after smelling stress sweat compared to sport sweat. If so, this would be further proof that stress sweat is an alarm pheromone, which, by definition, changes the way we behave after we inhale it.

A thought: Could stress sweat induce compassion in autistic people?

And another thought: If feelings have smells, is happiness also inhalable, communicable?

Are pheromones why the rhythm method doesn’t work?

Posted in news by jenapincott on August 2, 2009

Pregnancy_25_weeks For women not trying to get pregnant, life should be easy. Conception can only happen in the 12-24 hours after ovulation. Sure, sperm may last as many as 3-4 days in the genital tract, hanging around for the egg to arrive. But you’d think not having sex during the 4-5-day window would be sufficient to avoid mishaps. That’s what the rhythm method is — a natural form of birth control that relies on abstinence on fertile days.

But slips happen even among the most careful practitioners of the rhythm method. Some of this may have to do with women not keeping perfect track of their menstrual cycles or having naturally irregular cycles. (I discuss in BLONDES the evolutionary reasons why ovulation is hidden to both women and their partners.) The failure rate for rhythm method is 25 percent each year (with a perfect-use rate of 9 percent).

Why so high?

Another reason could be pheromones. The latest issue of my favorite journal, Medical Hypotheses, includes a submission that suggests that pheromones from men may cause an early ovulation in women. By invoking an early release of the egg — in advance of the expected fertile window — chances of fertilization are higher. As I mention in BLONDES, studies have the found that androstadienone, a testosterone-related compound found in men’s sweat, semen, and saliva, increases the amount of luteinizing hormone in women, which thereby triggering ovulation. It’s possible that high-testosterone men may be likelier to have this effect on their lovers. Their sweat smell alone may do the trick.

As I mentioned in an earlier post, there are other properties in semen that may also trigger early ovulation. For instance, seminal fluid contains follicle stimulating hormone (FSH) and luteinizing hormone (LH), which may coax the ovary to release an egg.

Despite the high failure rate, the Roman Catholic Chruch continues to promote the rhythm method, now renamed natural family planning (adding cervical mucus and temperature data to the regimen). Problem is, we don’t live in a clockwork universe, nor do we have clockwork bodies.

“Blondes” in Elle

Posted in media by jenapincott on July 27, 2009

Nice mention of BLONDES in ELLE magazine. Johanna Cox interviewed me for her fun article and mentioned the Hungarian hair-length study I describe in the book. A previous article also draws on some of the lighter topics in the book.

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


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

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.


Connect on Facebook

Top Posts & Pages