Science of Love, Sex, and Babies

Why are Men Mad About Mammaries?

Posted in news, psychology, science, sex by jenapincott on April 3, 2011

Why do men love breasts?

Let me count the theories:

1. Freudian (breasts remind men of their moms and the nurturing of childhood)
2. Evolutionary (breasts resemble buttocks, and prehuman ancestors always mounted from behind)
3. Reproductive (breasts are an indicator of age, and big breasts in particular are a marker of high estrogen levels, associated with fertility).

Do these reasons sufficiently explain why breasts are beloved — even in cultures that don’t eroticize them any more than the face?

If not, here’s another:

Breasts facilitate “pair-bonding” between couples. Men evolved to love breasts because women are likelier to have sex with — and/or become attached to — lovers who handle their breasts.

This idea came up in New York Times journalist John Tierney’s interview with Larry Young, a neuroscientist famous for his research on monogamy. According to Young, “[M]ore attention to breasts could help build long-term bonds through a ‘cocktail of ancient neuropeptides,’ like the oxytocin released during foreplay or orgasm.”

The same oxytocin circuit, he notes, is activated when a woman nurses her infant.

When women’s breasts are suckled, as they are during breastfeeding, the hormone oxytocin is released. Oxytocin makes the mother feel good and helps her bond with her baby. She feels loving and attached. The same reaction might happen if a man sucks and caresses a woman’s breasts during foreplay. In our ancestral past, the most titillated men may have been the ones to attract and retain mates and pass on their genes.

The “boobs-help-bonding” theory may not be the strongest explanation of why men love breasts, but it’s worth introducing to the debate. That said, there are many ladies out there for whom a lover’s suckling does nothing — and there are many breast-ogling boobs who know nothing of foreplay.

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What Singles Can Learn from Baby Talk

Posted in news, psychology, science by jenapincott on March 28, 2011

When you become a new parent you get a lot of advice on how to connect with your infant. To win her over, you’re told, talk the way she talks.  If Baby says “bah-bah-bah,” you say, “bah-bah-bah” back. You can make your “bah” sound like a real word by saying BAH-tel” or “BAH-th.” The content doesn’t really matter.  You just need make sure you sound like her.  Researchers call this “language style matching.” It draws the infant in and helps her connect with you. Experts can predict a baby’s attachment to her mother by how much they bah-bah back and forth during baby talk.

            Singles seeking love and connection can learn from this, according to a new study led by James Pennebaker and Molly Ireland at the University of Texas at Austin, and their colleagues at Northwestern University.  What the psychologists investigated is whether people on a first date who use similar words hit it off better than those who don’t.  Could language style predict whether you and your date will decide to see each other again and even have a strong and stable relationship eventually?

            To find out, the researchers recorded college students on speed dates. Thrown together for four-minute pairings, the men and women warmed up by asking each other the usual questions:  Where are you from?  What’s your major? How do you like college?

 Using a computer algorithm to analyze the speed-daters’ conversations, Pennebaker and Ireland found that men and women that wanted to see each other again matched each other’s function words significantly more often than those that had no interest in each other. Function words are like glue. They are not nouns or words; rather, they show how those words relate.  They are words like the, a, be, anything, that, will, him, and well. They are the yeses and okays and the pauses and interjections between words. They are the ifs, ands, and buts. By themselves they don’t sound like much, but they set a mood.

            The more a couple’s language styles matched, especially the function words, the likelier they were to hit it off. Couple whose speaking styles were in sync more than average were nearly four times as likely to desire a second date as those that were not.  About 77 percent of similar-sounding speed-daters desired a second date compared to only about half the dissimilar speakers.  Similar-speakers were also significantly more likely to be dating three months later.

            Language style matching is usually unconscious, according to the researchers.  It’s verbal body language.  Just as couples on the most successful dates make more eye contact, lean in toward one another, and otherwise echo each other’s body movements, they also echo each other’s choice of words.  We put ourselves in sync with people with whom we want to get close and stay close. 

Pennebaker and his team also used the alogrithm to test written correspondence for language style, and found that couples who had been dating a year or more were likelier to stay together if their writing styles in text messages matched. 

You can predict if you and your date or partner are in sync by taking Pennebakers’s online test at http://www.utpsyc.org/synch/.   Enter your and your love’s email or text correspondence and you’ll get a number that assesses how much your language matches up — which in turn may predict how well your relationship will hold up.

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If you and your partner use actual baby talk to communicate — that is, speaking in a high-pitched voice with elongated syllables to your ickle-bitty-peshus wuv –you may have an especially healthy long-term relationship. According to a study by researchers Meredith Bombar and Lawrence Littig, baby talk helps lovers enhance feelings of mutual intimacy and attachment to each other.  Compared to other couples, babytalkers are more secure and less avoidant in romantic relationships.

Why?  In effect, baby talk, when mutual, is not only a form of language style matching but also a way to reactivate primal circuits of attachment. It taps into the unconditional love of a parent for child.

The old “play” circuits are activated; as in any form of fantasy, baby talk allows a couple to step outside the limits of self, space, and time. Stress is reduced — the same reason why a recent study on light S&M found that couples who spank together stay together. Babytalking lovers get a blast of dopamine and oxytocin in areas of the brain involved in reward and bonding — the ventral tegmental area, orbitofrontal cortex, and anterior cingulate cortex.

Mutual use of high-pitched voices, soothing whispers, cooing, lisping, and making expressive faces is also a way of “looping” or “mirroring” affection. Along with the other bonding benefits, baby talk may be a way of flaunting one’s healthy emotional neural circuitry — suggesting not only love and commitment but also strong nurturing instincts.

Do babytalking couples make better parents?  Who knows — but secure, loving, long-term ones do.

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?

Are Americans more loving?

Posted in news by jenapincott on August 20, 2009

23-heidi-montag-spencer-pratt-american-flagI love the large cross-cultural surveys done by evolutionary psychologist David Schmitt and his colleagues at Bradley University. His latest adds evidence to the conviction that love is universal. Repeat: love is universal. To be universal, there must be a evolutionary reason — in other words, it must help our species to perpetuate somehow. As Schmitt explains:

Love can rivet our attention to a single mate, instigate the process of romantic flirtation, lead to systematic patterns of courtship behavior, and on occasion culminate in marriage. Love helps parents bond in healthy ways with newborn offspring, leads to informative adolescent infatuations before more serious romantic pursuits, and serves as a social glue for functional interchanges of support amongst family and friends.

But even if love is universal, there are some very interesting cultural distinctions that emerge in the study. Here are a few outcomes/insights derived from the answers of 15,234 participants from 48 nations:

Nationality affects emotional investment, an indicator of love. As measured by an Emotional Investment Scale, countries in which people scored highest are the United States, Slovenia, and Cyprus. Low-scoring nations were Tanzania, Hong Kong, and Japan.

Focusing on men alone, the countries with the most emotionally invested males are the United States, Brazil, Portugal, Argentina, Philippines, and Greece.

The countries with the most emotionally invested women are Slovenia, the United States, Malta, Cyprus, Australia, and Argentina.

In almost every country, women reported higher levels of emotional investment than did men. But there are a few notable exceptions: In Bolivia, men and women were identical in their average levels of Emotional Investment, and Malaysia, men scored higher than women (though not significantly so). The researchers suggest there is something restricting women’s reporting of their romantic investment in these two cultures.

Oddly, sex differences in emotional Investment were larger in nations with high gender equality (e.g., Switzerland, Australia, and Germany) and were smaller in nations with low gender equality (e.g., Turkey, South Korea, and Bolivia). The researchers claim: “What appears to be happening is that greater gender equality is associated with higher Emotional Investment among both men and women, but the accentuating effects of gender equality on Emotional Investment are greater among women, leading to larger levels of the naturally-occurring sex difference in Emotional Investment.”

Stress reduces emotional investment. In cultures with high stress (e.g., Bolivia, Indonesia, and Malaysia), levels of Emotional Investment were significantly lower, especially among women. High national levels of stress (Infant Mortality rates, Childhood Malnutrition rates, and the Pathogen Stress experienced in local environments) —were also linked to lower levels of Emotional Investment. This is predicted by evolutionary theory: harsh conditions lead people to develop insecure attachment levels that result in lower emotional investment.

Emotional investment doesn’t lead to higher fertility rates.To the contrary: countries with lower emotional investment levels among women were related to higher fertility levels.

Countries scoring high in emotional investment don’t have stronger marriages. To the contrary: national levels of emotional investment were positively correlated with divorce rate, unrestricted sociosexuality, short-term mating interests, and the tendency to engage in short-term mate poaching (i.e., stealing someone else’s partner for a short-term sexual affair)

Emotional investment is linked with commitment, but there are nationwide exceptions. Individuals from North America who reported more unrestricted sociosexuality reported lower levels of emotional investment. Similar results were observed within the world regions of South America, Eastern Europe, and Oceania. However, unrestricted sociosexual individuals from South/Southeast Asia and East Asia reported higher levels of emotional investment. Moreover, individuals from Africa who were interested in short-term mating reported significantly higher levels of emotional investment.

Emotional investment peaks when dating one person. It’s somewhat lower among those who are living with someone, married, or currently single (in that order); and is significantly lower than that among those who have never had sex.

Schmitt admits that people from different cultures may express emotional investment differently (have different response biases) and in ways hard to quantify on a standardized scale. Moreover, the questions were written in English and translated into the native languages of the participants. Could this possibly bias the U.S. results — or are Americans really more loving?

(My book, BLONDES, provides a more detailed description of some of Schmitt’s fascinating work with the International Sexuality Description Project.)

Why do couples babytalk?

Posted in news by jenapincott on April 6, 2009

diaper-personals-site Several times in the last week, twice on the subway and once in a cafe, I sat near a baby-talking couple spweaking wike dis, in a wery squeaky voice, saying wuv wu oochy-coochie poopy. They were all adults in their mid-twenties to mid-forties. They wore leather jackets, high heels, makeup, suits-and-ties. But they acted as if they were in diapers.

I think terms of endearment — Cupcake, Honey, Tootie, Mochi — are sweet. It’s the bwack-and-forth bwabble that bwothers me a bwit, only because I don’t understand the appeal. Of all forms of role play, infantilizing a boyfriend or husband — talking to him as a little girl would a baby doll — just doesn’t seem romantic or arousing.

Yet psychologists consider lovers’ babytalk a real and valid form of bonding. A study by Meredith Bombar and Lawrence Littig suggests it’s a good sign: Babytalkers were more secure and less avoidant in romantic relationships. In effect they’re reactivating primal circuits of attachment. Ickle-bitty-peshus-wuvy cooing reinforces intimacy, tapping into the unconditional love of a parent for child. The old “play” circuits are also activated; as in any form of fantasy, babytalk allows a couple to step outside the limits of self, space, and time. Stress is reduced — the same reason why a recent study on light S&M found that couples who spank together stay together. Babytalking lovers get a blast of dopamine and oxytocin in areas of the brain involved in reward and bonding — the ventral tegmental area, orbitofrontal cortex, and anterior cingulate cortex.

According to psychologists, mutual use of high-pitched voices, soothing whispers, cooing, lisping, and overexpressive faces is a way of “looping” or “mirroring” affection. Exclusive and intimate, it’s an act of trust-building. Think of it as verbal swaddling. Along with the other bonding benefits, babytalk may be a way of flaunting one’s healthy emotional neural circuitry — suggesting not only love and commitment but also strong parental instincts. (Take it to an extreme and more interesting interpretations may be made.)

Psychologists, then, don’t seem troubled by babytalk between lovers. In moderation it’s considered a healthy indulgence. Even so, it’s not my idea of pampering.

What are “female hormones” doing in semen?”

Posted in news by jenapincott on March 29, 2009

queens2
It happened again to my friend C. — she had an affair with a dashing Moroccan guy two weeks ago and got her period early. She always experiences short or untimely cycles in the beginning of relationships, and do many women I know. One study found that one out of every three gals reports getting her period early in response to a new sex partner, or — as been found among Army wives — a visit from an existing one who lives far away. Even among women whose cycles are like clockwork, novel sex can make them cuckoo.

There are many factors that can throw off a cycle, including emotional excitement and stress. As I discuss in BLONDES, there’s evidence that sweat and semen can, too. Digging deeper into the psychobiology of semen, I stumbled upon a provocative theory. It all begins with the discovery that semen contains “female hormones” including follicle stimulating hormone (FSH) and luteinizing hormone (LH).

Why are these so-called female hormones in semen? The answer, according evolutionary psychologists Gordon Gallup and Rebecca Burch at SUNY Albany, is that they increase the man’s chances of impregnating the woman. Unlike females of other species, women don’t advertise when they’re ovulating. And because ovulation is concealed and the fertile window easy to miss, it may take many months of regular sex for conception to happen.

But what would happen if men could control the timing?

Turns out that hormones in semen may do exactly that — by mimicking the conditions of ovulation. The FSH in semen causes an egg in an ovary to ripen and mature. The LH in semen triggers ovulation and the release of the egg. If a woman is near ovulation — say, in the first week or so of her cycle — these seminal chemicals may be sufficient to induce an early release of the egg. By synchronizing ovulation with sex, a man improves his chances of conception in a casual encounter.

As a reason why female hormones are present in human sperm, the theory sounds plausible. Women conceal ovulation to prevent men from knowing when they’re fertile (for reasons I discuss in the book). Men, in an evolutionary tit for tat, developed ways to induce ovulation to increase the chances of conception. Indeed, when researchers analyzed the sperm of chimpanzees, which advertise ovulation rather than conceal it, levels of the female hormones LH and FSH were low to nonexistent.

Of course, questions remain: How do women’s cycles normalize a few months into the relationship despite ovulation-inducing hormones? Are FSH and LH hormones exclusively “female;” what other purposes might they have for men?

As for my friend C., she didn’t get pregnant from her fling. Fortunately, her cycle only accelerated. But the risk of a surprise pregnancy is one more reason why it’s a good idea to use a condom.

The “psych” in semen

Posted in news by jenapincott on March 25, 2009

hypnotize2My post on mind control properties in semen still attracts a disturbing amount of attention. So to appease your curiosity — and, I’ll admit it, mine — I’ve decided to do a little more investigation into the compounds in semen that may enter the bloodstream after sex. Some may have an indirect effect on the recipient’s hormones. A few may breach the blood-brain barrier, directly influencing mood and sex drive. Several, but not all, of the chemicals have been studied and proven to pass through the vaginal walls. From an evolutionary perspective, mood-modulating components in semen may give a woman an incentive to be in a committed relationship with regular, frequent sex. Apparently, the goo is bonding.

The information below comes from SUNY Albany evolutionary psychologists Gordon Gallup and Rebecca Burch, whose fascinating study on semen and depression I describe in BLONDES. Gallup and Burch wrote a chapter, “The psychobiology of human semen,” published in a compilation of research on sexuality. What they describe, I think, is fascinating.

The primary putative mind-altering ingredients in semen:

Luteinizing hormone: astounding concentration in semen; linked to high sperm count and motility. Absorption into female bloodstream may facilitate or even induce ovulation.

Prolactin: influences maternal behavior, oxytocin secretion; mediates bonding

Estrone and estradiol: assists in recipient’s absorption of other compounds such as progesterone; may boost woman’s sexual motivation and mood

Testosterone: may increase sex drive and motivation; the more intercourse, the higher the testosterone levels in women, and the stronger the sexual desire. More than half the amount of testosterone in sperm has been found to be absorbed by the vagina.

Cytokines: these are the “warriors,” they suppress immune reaction to semen invading the vagina and cervix and therefore increase likelihood of pregnancy

Enkephalins: these opioids may contribute to orgasmic experience. They may decrease anxiety and cause drowsiness after sex.  There’s also speculation that they assist in immune function and “reinforcing effects” — making a woman come back for more, i.e. addiction  (although the absorption rate in female bloodstream is unknown)

Oxytocin: assists in stimulation of ovulation, increases production of other hormones, initiates bonding, facilitates orgasmic contractions; may strengthen bonding and make sexual activity more rewarding

Placental proteins, including human chorionic gonadotrophin (hcg) and human placental lactogen: associated with sperm motility; may increase chances of pregnancy

Relaxin: made in the prostate, this hormone may facilitate fertilization, implantation, and uterine growth. The role of relaxin suggests that women should keep having a lot of sex during pregnancy because sperm has pregnancy-maintaining properties. Relaxin also facilitates implantation and prevents preterm labor.

Thyrotropin-releasing hormones: potential anti-depressive; works by stimulating the release of thyroid-stimulating hormone, which in turn triggers hormone production in the mood-mediating thyroid gland. In pill form, it’s used to treat PMS and depression.

Serotonin: increases sperm motility.  It also mediates mood, although not much known yet about vaginal absorption. Even if it doesn’t make it to the brain, it may indirectly alter behavior and emotions by contributing the building blocks of serotonin

Melatonin: increases effects of steroid hormones; induces sleepiness and fatigue, which may help the woman relax after sex; may stimulate reproductive function, also mood mediator; low melatonin levels are associated with depression and “reality disturbance”

Tyrosine: a precursor of neurotransmitters such as dopamine, the hormone of reward and addiction, and norepinephrine, involved in attention and arousal

Oh, and there’s also sperm in there, the DNA-bearing courier. Sperm is less than 3 percent the total volume of semen. But as it turns out, the bath water is nearly as important as the baby.

n.b. Although not yet studied, researchers suspect that these chemicals in semen may also enter the bloodstream through mucous membranes when having oral and anal sex. If so, straight women aren’t the only lucky recipients.

A new theory on why men love breasts?

Posted in news by jenapincott on January 19, 2009

31269245hc0Why do men love breasts? In BLONDES I describe the most interesting and promising theories — from the Freudian (breasts remind men of Mom) to the evolutionary (breasts resemble buttocks and prehuman ancestors mounted from behind), and the reproductive (breasts are an indicator of age and big breasts are a marker of high estrogen levels). These are some of the most likely reasons why breasts are beloved even in cultures that don’t eroticize them any more than the face.

A new spin on the male fascination with breasts came up this week in John Tierney’s interview with neuroscientist Larry Young on love blockers. According to Young, “more frequent sex and more attention to breasts could help build long-term bonds through a ‘cocktail of ancient neuropeptides,’ like the oxytocin released during foreplay or orgasm.” The same oxytocin circuit, he notes, is activated when a woman nurses her infant.

The article doesn’t connect all the dots, but the suggestion is as follows: The hormone oxytocin is released when breastfeeding, making the mother feel good and helping her bond with baby. Sucking and caressing a woman’s breasts during foreplay may also trigger oxytocin release. When oxytocin hits the brain, women become more trusting and attached. Men evolved to pay attention to breasts as a means of attracting and retaining lovers.

The “boobs help bonding” theory may not be the strongest explanation of why men love breasts, but it’s worth introducing to the debate. That said, I strongly suspect that there are many women out there for whom a lover’s suckling does nothing — and there are many breast-ogling guys who know nothing of foreplay.

Women zero in on partner’s scent only

Posted in news by jenapincott on January 17, 2009

87armpitWhat a month. First, sex with her partner makes a woman less attracted to other guys. Then speculation about mind control properties in semen. And now research on how love affects women’s sensitivity to men’s body odor.

According to a new study led by Johan Lundstrom at the Monell Chemical Senses Center, love inhibits women’s ability to identify the body odors of their male friends. Twenty women, all deeply in love, were asked to smell the body odor of same-sex friends, male friends, and their partners. Although they were able to easily identify their partner’s scent, the women had difficulty placing the scent of their male friends. And only the scent of male friends eluded them. When asked to identify the sweat of their female friends, the women were much more accurate. It’s as if falling in love disables a woman’s sensory mechanism to all men but her beloved. Not only does love blind us, it apparently makes us partial amnosiacs. (Read BLONDES for more on sex and smell.)

How does this happen? According to the researchers, women’s sensitivity to men’s odor is hormonally modulated. “Romantic love,” they say, “deflects attention away from potential new partners…[and is] likely mediated by circulating neuropeptides.” Love leads us by the nose. Body odors help us bond.

It’s all very interesting, and I’d love to see more in-depth research. The women weren’t tested for their sensitivity to their male friends’ body odors before they fell in love. Yes, they could identify their female friends’ body odors more easily than those of their male friends, implying a sexual mechanism — but that might be because women are more physically intimate, spending more time in one another’s rooms, playing with one another’s hair, and so on. And how exactly does it work — does something in a man’s sweat trigger a hormone that flips some smell-related switch? Does it make a difference if a woman is having protected sex or is on the Pill? Is this another case of mind control? And importantly: could it work on men, too?

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