Chapter 12. Sex: Evolutionary, Hormonal, and Neural Bases
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by Alison George Misguided notions about our sexual appetites are missing the bigger picture and making people unhappy, says Emily Nagoski Why is there no such thing as a sex drive? A drive is a motivational system to deal with life-or-death issues, like hunger or being too cold. You're not going to die if you don't have sex. But biologists might say that if you don't reproduce, that is a form of death Yes. That's the argument that was used when desire was being added to the way sexual dysfunctions were diagnosed in the 1970s, to justify the framing of sexual desire as a drive. But when it comes to sex, there just isn't any physical evidence of a drive mechanism. So what's going on? If sex is a drive then desire should be spontaneous, like a hunger. When you see a sexy person or have a stray sexy thought, it activates an internal craving or urge for sex. That's called "spontaneous desire". It feels like it comes out of the blue. But there is another way of experiencing desire which is also healthy and normal, called "responsive desire", where your interest only emerges in response to arousal. So, your partner comes over and starts kissing your neck and you're like, "oh, right, sex, that's a good idea". Do you think an absence of spontaneous desire is normal? Yes. If our metaphor for desire is hunger, if you are never hungry for food there will be dire consequences and that's clearly a disorder, right? That's a medical problem that needs to be fixed. But not experiencing spontaneous hunger for sex doesn't have dire consequences; it is not a medical disorder. I think the reason we expect everyone to have spontaneous desire is because that's how most men experience it. © Copyright Reed Business Information Ltd
Keyword: Sexual Behavior
Link ID: 20759 - Posted: 04.06.2015
Hannah Devlin, science correspondent They may stop short of singing The Bells of Saint Mary’s, as demonstrated by the mouse organ in Monty Python, but scientists have discovered that male mice woo females with ultrasonic songs. The study shows for the first time that mouse song varies depending on the context and that male mice have a specific style of vocalisation reserved for when they smell a female in the vicinity. In turn, females appear to be more interested in this specific style of serenade than other types of squeak that male mice produce. “It was surprising to me how much change occurs to these songs in different social contexts, when the songs are thought to be innate,” said Erich Jarvis, who led the work at Duke University in North Carolina. “It is clear that the mouse’s ability to vocalise is a lot more limited than a songbird’s or human’s, and yet it’s remarkable that we can find these differences in song complexity.” The findings place mice in an elite group of animal vocalisers, that was once thought to be limited to birds, whales, and some primates. Mouse song is too high-pitched for the human ear to detect, but when listened to at a lower frequency, it sounds somewhere between birdsong and the noise of clean glass being scrubbed. The Duke University team recorded the male mice when they were roaming around their cages, when they were exposed to the smell of female urine and when they were placed in the presence of a female mouse. They found that males sing louder and more complex songs when they smell a female but don’t see her. By comparison, the songs were longer and simpler when they were directly addressing their potential mate, according to the findings published in Frontiers of Behavioural Neuroscience. © 2015 Guardian News and Media Limited
Sara Reardon A new study finds that children's cognitive skills are linked to family income. The stress of growing up poor can hurt a child’s brain development starting before birth, research suggests — and even very small differences in income can have major effects on the brain. Researchers have long suspected that children’s behaviour and cognitive abilities are linked to their socioeconomic status, particularly for those who are very poor. The reasons have never been clear, although stressful home environments, poor nutrition, exposure to industrial chemicals such as lead and lack of access to good education are often cited as possible factors. In the largest study of its kind, published on 30 March in Nature Neuroscience1, a team led by neuroscientists Kimberly Noble from Columbia University in New York City and Elizabeth Sowell from Children's Hospital Los Angeles, California, looked into the biological underpinnings of these effects. They imaged the brains of 1,099 children, adolescents and young adults in several US cities. Because people with lower incomes in the United States are more likely to be from minority ethnic groups, the team mapped each child’s genetic ancestry and then adjusted the calculations so that the effects of poverty would not be skewed by the small differences in brain structure between ethnic groups. The brains of children from the lowest income bracket — less than US$25,000 — had up to 6% less surface area than did those of children from families making more than US$150,000, the researchers found. In children from the poorest families, income disparities of a few thousand dollars were associated with major differences in brain structure, particularly in areas associated with language and decision-making skills. Children's scores on tests measuring cognitive skills, such as reading and memory ability, also declined with parental income. © 2015 Nature Publishing Group,
By Anna Azvolinsky Differences in male and female rodent sexual behaviors are programmed during brain development, but how exactly this occurs is not clear. In the preoptic area (POA) of the brain—a region necessary for male sex behavior—the female phenotype results from repression of male-linked genes by DNA methylation, according to a study published today (March 30) in Nature Neuroscience. There is very little known about how the brain is masculinized—and even less about how it is feminized—even though the question has been studied for more than 50 years, said Bridget Nugent, study author and now a postdoctoral fellow at the University of Pennsylvania. These sex differences in the brain are programmed toward the end of fetal development, through to one week after birth in rodents. In males, testicular hormones drive masculinization of the brain; this was thought to occur by direct induction of gene expression by hormone-associated transcription factors. Because a feminized brain occurred in the absence of ovarian hormone signals, most researchers assumed that the female brain and behavior was a sort of default state, programmed during development when no male hormones are present. But the downstream mechanisms of how hormones can modify gene expression were not previously known. “This study reveals that DNA methylation plays an important role in regulating sexual differentiation,” said Nirao Shah, who also studies the neural basis for sex-specific behaviors at the University of California, San Francisco, but was not involved with the work. © 1986-2015 The Scientist
Nicholette Zeliadt, One afternoon in October 2012, a communication therapist from Manchester visited the home of Laura and her three children. Laura sat down at a small white table in a dimly lit room to feed her 10-month-old daughter, Bethany, while the therapist set up a video camera to record the pair’s every movement. (Names of research participants have been changed to protect privacy.) Bethany sat quietly in her high chair, nibbling on macaroni and cheese. She picked up a slimy noodle with her tiny fingers, looked up at Laura and thrust out her hand. “Oh, Mommy’s going to have some, yum,” Laura said. “Clever girl!” Bethany beamed a toothy grin at her mother and let out a brief squeal of laughter, and then turned her head to peer out the window as a bus rumbled by. “Oh, you can hear the bus,” Laura said. “Can you say ‘bus?’” “Bah!” Bethany exclaimed. “Yeah, bus!” Laura said. This ordinary domestic moment, immortalized in the video, is part of the first rigorous test of a longstanding idea: that the everyday interactions between caregiver and child can shape the course of autism1. The dynamic exchanges with a caregiver are a crucial part of any child’s development. As Bethany and her mother chatter away, responding to each other’s glances and comments, for example, the little girl is learning how to combine gestures and words to communicate her thoughts. In a child with autism, however, this ‘social feedback loop’ might go awry. An infant who avoids making eye contact, pays little attention to faces and doesn’t respond to his or her name gives parents few opportunities to engage. The resulting lack of social interaction may reinforce the baby’s withdrawal, funneling into a negative feedback loop that intensifies mild symptoms into a full-blown disorder. © 2015 Guardian News and Media Limited
Link ID: 20733 - Posted: 03.30.2015
By BONNIE ROCHMAN Reasons Why I Shouldn’t Have to Go Tonight: If I wanted to talk about it, I would. / It’s my body. / It’s a waste of time. / It’s a waste of money. / I know what I need to know. / It sounds pretty stupid to me. PLEASE DON’T MAKE ME GO. I DON’T WANT TO GO. The plea came from Leah Likin, a fifth grader. It was addressed to her mother, who had registered both of them for a two-part course on puberty called “For Girls Only.” The missive, which included additional objections, failed: Mother took daughter anyway. But Leah had plenty of company, peers who shared her resistance, their arms crossed, their eyes downcast. Last year, the course, which is split into sessions for preteen boys and girls and held mostly in and around Seattle, and also in the Bay Area, pulled in 14,000 attendees. They heard about it from their pediatricians, or through word of mouth. The creator of the course, Julie Metzger, has been trying for nearly three decades to turn what’s so often at best a blush-inducing experience — the “facts of life” talk — into a candid dialogue between parents and children. In the mid-1980s, she was a graduate student at the University of Washington School of Nursing when she reviewed survey data on how women had learned about menarche, or the onset of menstruation, for her master’s thesis. Most reported getting information from gym class or their mothers. “You can picture those conversations lasting from 10 seconds to 10 hours,” Metzger says. “And I thought, Wouldn’t it be interesting if you actually had a class where you sit with your parents and hear these things from someone? What if that class were fun and funny and interactive?” Metzger, who is 56 and vigorous, with flushed cheeks and blue eyes, says she has always been comfortable talking about sexuality; her father was a urologist, her mother a nurse. “Hand me a microphone,” she says. “I get so into this topic that I can make myself cry in front of the class, and it’s real.” © 2015 The New York Times Company
Keyword: Sexual Behavior
Link ID: 20722 - Posted: 03.26.2015
By Camilla Turner It is one of life’s most enduring mysteries. A question that music, poetry, myth and legend has, for thousands of years, tried but failed to answer. However, we may now be a step closer to discovering what love is, thanks to a scientific study that has obtained the first empirical evidence of love-related alterations in the brain. A team of researchers from universities in China and New York used MRI scans to track the physical effects of love on the brain and has pieced together a “love map” of the human mind. The study found that several areas of the brain showed increased activity in those who were in love, including in the parts of the brain linked to reward and motivation. The researchers said their results shed light on the “underlying mechanisms of romantic love” and would pave the way for a brain scan that could act as a “love test”. Scientists recruited 100 students from Southwest University in Chongqing, China, who were divided into three groups according to their relationship status: an “in-love” group, comprised of those who were in love at the time; an “ended-love” group, who had recently ended loving relationships; and a “single” group, who had never been in love. Participants were told not to think of anything while their brains were scanned, so that researchers could monitor the differences between the brains of students in all three groups. © Copyright of Telegraph Media Group Limited 2015
Keyword: Sexual Behavior
Link ID: 20692 - Posted: 03.17.2015
by Penny Sarchet For some of us, it might have been behind the bikeshed. Not so the African cotton leafworm moth (Spodoptera littoralis), which can choose any one of a vast number of plant species to mate on. But these moths remember their first time, returning to the same species in search of other mates. In the wild, this moth feeds and mates on species from as many as 40 different plant families. That much choice means there's usually something available to eat, but selecting and remembering the best plants is tricky. So, recalling what you ate as a larva, or where you first copulated, may help narrow down which plants provide better quality food or are more likely to attract other potential mates. Magali Proffit and David Carrasco of the Swedish University of Agricultural Sciences in Alnarp and their colleagues have discovered that this moth's first mating experience shapes its future preferences. These moths have an innate preference for cotton plants over cabbage. But when the researchers made them mate for the first time on cabbage, the moths later showed an increased preference for mating or laying eggs on this plant. Further experiments revealed that moths didn't just favour plants they were familiar with, even in combination with a sex pheromone – mating had to be involved. © Copyright Reed Business Information Ltd.
By Nicholas Weiler Killer whales wouldn’t get far without their old ladies. A 9-year study of orcas summering off the southern tip of Vancouver Island in the Pacific Northwest finds that menopausal females usually lead their families to find salmon, particularly when the fish are scarce. Older females’ years of foraging experience may help their clans survive in years of famine, an evolutionary benefit that could explain why—like humans—female orcas live for decades past their reproductive prime. “Menopause is a really bizarre trait. Evolutionarily it doesn’t make sense,” says biologist Lauren Brent of the University of Exeter in the United Kingdom, who led the new study. Most animals keep having babies until they drop, part of the evolutionary drive to spread their genes as widely as possible. Only female humans, pilot whales, and killer whales are known to go through menopause: At a certain age, they stop reproducing, but continue to lead long, productive lives. Like humans, female killer whales stop giving birth by about 40, but can live into their 90s. Anthropologists have proposed a controversial explanation for menopause in humans: that grandmothers contribute to their genetic legacies by helping their children and grandchildren survive and reproduce. In hunter-gatherer and other societies, elders find extra food, babysit, and remember tribal lore about how to live through floods, famines, and other hardships. According to the “grandmother hypothesis,” this contribution is so valuable that it helped spur the evolution of women’s long postreproductive lives. Orcas too depend on their elders: Adult killer whales’ mortality rates skyrocket after their elderly mothers die. But how the menopausal whales might help their children survive was not clear, Brent says. © 2015 American Association for the Advancement of Science.
By David Masci Potential Republican presidential candidate Dr. Ben Carson made news earlier this week when he said that being gay is a “choice,” but when it comes to public opinion, polls show that Americans remain divided over whether “nature” or “nurture” is ultimately responsible for sexual orientation. Four-in-ten Americans (42%) said that being gay or lesbian is “just the way some choose to live,” while a similar share (41%) said that “people are born gay or lesbian,” according to the most recent Pew Research Center poll on the issue, conducted in 2013. Fewer U.S. adults (8%) said that people are gay or lesbian due to their upbringing, while another one-in-ten (9%) said they didn’t know or declined to give a response. People with the most education are the most likely to say that gays and lesbians were born that way. Indeed, 58% of Americans with a postgraduate degree say that people are born gay or lesbian, compared with just 35% of those with a high school diploma or less. The percentage of all Americans who believe that people are born gay or lesbian has roughly doubled (from 20% to 41%) since 1985, when the question was asked in a Los Angeles Times survey. More than three decades of Gallup polls also show a considerable rise in the view that being gay or lesbian is a product of “nature” rather than “nurture.” But the most recent survey, in 2014, still finds that the nation remains split in its feelings on the origins of sexual orientation. Copyright 2015 Pew Research Center
Keyword: Sexual Behavior
Link ID: 20658 - Posted: 03.07.2015
Tristram Wyatt This Valentine’s Day, like every year, there was a rash of stories in the news about sexy smells and pheromones. You could be forgiven for thinking that human ‘sex pheromones’, in particular the ‘male molecule’ androstadienone, were well established: countless ‘human pheromones’ websites sell it and there are tens of apparently scientific studies on androstadienone published in science journals. These studies are cited hundreds of times and have ended up being treated as fact in books on sexual medicine and even commentary on legislation. The birth place of the pheromone myth was a 1991 conference in Paris sponsored by a US corporation, EROX, which had an interest in patenting androstadienone and another molecule - estratetraenol, from women - as ‘human pheromones’. Unwittingly, leading mammalian olfaction scientists lent the conference credibility. Slotted into the programme and conference proceedings was the short ‘study-zero’ paper on the ‘Effect of putative pheromones on the electrical activity of the human vomeronasal organ and olfactory epithelium’. To my surprise, the authors gave no details at all of how these molecules had been extracted, identified, and tested in bioassays - all routinely required steps in the exhaustive process before any molecule can be shown to be a species-wide chemical signal, a pheromone. Instead there was just a footnote: ‘These putative pheromones were supplied by EROX Corporation’. The missing, essential details were never published. (The claim by EROX-sponsored scientists that adult humans have a functioning vomeronasal organ, against all the evidence, is a story for another day). © 2015 Guardian News and Media Limited
By JULIE HOLLAND WOMEN are moody. By evolutionary design, we are hard-wired to be sensitive to our environments, empathic to our children’s needs and intuitive of our partners’ intentions. This is basic to our survival and that of our offspring. Some research suggests that women are often better at articulating their feelings than men because as the female brain develops, more capacity is reserved for language, memory, hearing and observing emotions in others. These are observations rooted in biology, not intended to mesh with any kind of pro- or anti-feminist ideology. But they do have social implications. Women’s emotionality is a sign of health, not disease; it is a source of power. But we are under constant pressure to restrain our emotional lives. We have been taught to apologize for our tears, to suppress our anger and to fear being called hysterical. The pharmaceutical industry plays on that fear, targeting women in a barrage of advertising on daytime talk shows and in magazines. More Americans are on psychiatric medications than ever before, and in my experience they are staying on them far longer than was ever intended. Sales of antidepressants and antianxiety meds have been booming in the past two decades, and they’ve recently been outpaced by an antipsychotic, Abilify, that is the No. 1 seller among all drugs in the United States, not just psychiatric ones. As a psychiatrist practicing for 20 years, I must tell you, this is insane. At least one in four women in America now takes a psychiatric medication, compared with one in seven men. Women are nearly twice as likely to receive a diagnosis of depression or anxiety disorder than men are. For many women, these drugs greatly improve their lives. But for others they aren’t necessary. The increase in prescriptions for psychiatric medications, often by doctors in other specialties, is creating a new normal, encouraging more women to seek chemical assistance. Whether a woman needs these drugs should be a medical decision, not a response to peer pressure and consumerism. © 2015 The New York Times Company
By Nicholas Weiler The grizzled wolf stalks from her rival’s den, her mouth caked with blood of the pups she has just killed. It’s a brutal form of birth control, but only the pack leader is allowed to keep her young. For her, this is a selfish strategy—only her pups will carry on the future of the pack. But it may also help the group keep its own numbers in check and avoid outstripping its resources. A new survey of mammalian carnivores worldwide proposes that many large predators have the ability to limit their own numbers. The results, though preliminary, could help explain how top predators keep the food chains beneath them in balance. Researchers often assume that predator numbers grow and shrink based on their food supply, says evolutionary biologist Blaire Van Valkenburgh of the University of California, Los Angeles, who was not involved in the new study. But several recent examples, including an analysis of the resurgent wolves of Yellowstone National Park, revealed that some large predators keep their own numbers in check. The new paper is the first to bring all the evidence together, Van Valkenburgh says, and presents a “convincing correlation.” Hunting and habitat loss are killing off big carnivores around the world, just as ecologists are discovering how important they are for keeping ecosystems in balance. Mountain lions sustain woodlands by hunting deer that would otherwise graze the landscape bare. Coyotes protect scrub-dwelling birds by keeping raccoons and foxes in line. Where top carnivores disappear, these smaller predators often explode in numbers, with potentially disastrous consequences for small birds and mammals. © 2015 American Association for the Advancement of Science
// by Jennifer Viegas It’s long been suspected that males of many species, including humans, can sniff out whether a female is pregnant, and now new research suggests that some — if not all — female primates release a natural “pregnancy perfume” that males can probably detect. What’s more, such scents appear to broadcast whether the mom-to-be is carrying a boy or a girl. The study, published in the journal Biology Letters, focused on lemurs as a model for primates. It presents the first direct evidence in any animal species that a pregnant mother’s scent differs depending on the sex of her baby. The scent signatures “may help guide social interactions, potentially promoting mother–infant recognition, reducing intragroup conflict” or sort out paternity, wrote authors Jeremy Crawford and Christine Drea. The latter presents a loaded scenario, as it could be that males can sense — even before the birth — whether they fathered the baby. The researchers additionally suspect that odors advertising fetal sex may help dads and moms prepare for what’s to come. Crawford, from the University of California, Berkeley, and Drea, from Duke University, used cotton swabs to collect scent secretions from the genital regions of 12 female ringtailed lemurs at the Duke Lemur Center in Durham, N.C., before and during pregnancy. The scientists next used chemical analysis to identify the hundreds of ingredients that make up each female’s scent change during pregnancy. A surprising finding from this is that expectant lemur moms give off simpler scents that contain fewer odor compounds compared with their pre-pregnancy bouquet. The change is more pronounced when the moms are carrying boys, Drea said. © 2015 Discovery Communications, LLC.
By Emily Underwood Infants born prematurely are more than twice as likely to have difficulty hearing and processing words than those carried to full-term, likely because brain regions that process sounds aren’t sufficiently developed at the time of delivery. Now, an unusual study with 40 preemies suggests that recreating a womblike environment with recordings of a mother's heartbeat and voice could potentially correct these deficits. "This is the kind of study where you think ‘Yes, I can believe these results,’ " because they fit well with what scientists know about fetal brain development, says cognitive scientist Karin Stromswold of Rutgers University, New Brunswick, in New Jersey. A fetus starts to hear at about 24 weeks of gestation, as neurons migrate to—and form connections in—the auditory cortex, a brain region that processes sound, Stromswold explains. Once the auditory cortex starts to function, a fetus normally hears mostly low-frequency sounds—its mother’s heartbeat, for example, and the melody and rhythm of her voice. Higher frequency tones made outside of the mother's body, such as consonants, are largely drowned out. Researchers believe that this introduction to the melody and rhythm of speech, prior to hearing individual words, may be a key part of early language acquisition that gets disrupted when a baby is born too soon. In addition to being bombarded with the bright lights, chemical smells, and shrill sounds of a hospital’s intensive care unit, preemies are largely deprived of the sensations they'd get in the womb, such as their mother's heartbeat and voice, says Amir Lahav, a neuroscientist at Harvard Medical School in Boston. Although mothers are sometimes allowed to hold premature newborns for short periods of time, the infants are often considered too fragile to leave their temperature- and humidity-controlled incubators, he says. Preemies often have their eyes covered to block out light, and previous studies have shown that reducing overall levels of high-frequency noise in a neonatal intensive care unit—by lowering the number of incubators in a unit, for example, or giving preemies earplugs—can improve premature babies' outcomes. Few studies have actively simulated a womblike environment, however, he says. © 2015 American Association for the Advancement of Science.
Claire Ainsworth As a clinical geneticist, Paul James is accustomed to discussing some of the most delicate issues with his patients. But in early 2010, he found himself having a particularly awkward conversation about sex. A 46-year-old pregnant woman had visited his clinic at the Royal Melbourne Hospital in Australia to hear the results of an amniocentesis test to screen her baby's chromosomes for abnormalities. The baby was fine — but follow-up tests had revealed something astonishing about the mother. Her body was built of cells from two individuals, probably from twin embryos that had merged in her own mother's womb. And there was more. One set of cells carried two X chromosomes, the complement that typically makes a person female; the other had an X and a Y. Halfway through her fifth decade and pregnant with her third child, the woman learned for the first time that a large part of her body was chromosomally male1. “That's kind of science-fiction material for someone who just came in for an amniocentesis,” says James. Sex can be much more complicated than it at first seems. According to the simple scenario, the presence or absence of a Y chromosome is what counts: with it, you are male, and without it, you are female. But doctors have long known that some people straddle the boundary — their sex chromosomes say one thing, but their gonads (ovaries or testes) or sexual anatomy say another. Parents of children with these kinds of conditions — known as intersex conditions, or differences or disorders of sex development (DSDs) — often face difficult decisions about whether to bring up their child as a boy or a girl. Some researchers now say that as many as 1 person in 100 has some form of DSD2. © 2015 Nature Publishing Group
Keyword: Sexual Behavior
Link ID: 20589 - Posted: 02.18.2015
Berit Brogaard On popular websites, we read headlines such as “Scientists are finding that love really is a chemical addiction between people.” Love, of course, is not literally a chemical addiction. It’s a drive perhaps, or a feeling or an emotion, but not a chemical addiction or even a chemical state. Nonetheless, romantic love, no doubt, often has a distinct physiological, bodily, and chemical profile. When you fall in love, your body chemicals go haywire. The exciting, scary, almost paranormal and unpredictable elements of love stem, in part, from hyper-stimulation of the limbic brain’s fear center known as the amygdala. It’s a tiny, almond-shaped brain region in the temporal lobe on the side of your head. In terms of evolutionary history, this brain region is old. It developed millions of years before the neocortex, the part of the brain responsible for logical thought and reasoning. While it has numerous biological functions, the prime role of the amagdala is to process negative emotional stimuli. Significant changes to normal amygdala activation are associated with serious psychological disorders. For example, human schizophrenics have significantly less activation in the amygdala and the memory system (the hippocampus), which is due to a substantial reduction in the size of these areas. People with depression, anxiety, and attachment insecurity, on the other hand, have significantly increased blood flow in the amygdala and memory system. Neuroscientist Justin Feinstein and his colleagues (2010) studied a woman whose amygdala was destroyed after a rare brain condition. They exposed her to pictures of spiders and snakes, took her on a tour of the world’s scariest haunted house, and had her take notes about her emotional state when she heard a beep from a random beeper that had been attached to her. After three months of investigation, the researchers concluded that the woman could not experience fear. This is very good evidence for the idea that the amygdala is the main center for fear processing. (The chief competing hypothesis is that fear is processed in a brain region that receives its main information from the amygdala.) © 2015 Salon Media Group, Inc.
By Rachel Ehrenberg SAN JOSE, Calif. — New moms suffering from postpartum depression change their activity on Facebook, suggesting that the social media site could help detect the onset of the baby blues. Many new parents share pictures and videos of their babies on Facebook and use the site to interact with friends they might be too busy to see in person. But compared with most typical new moms, those suffering from postpartum depression are less active on the social media site, Munmun De Choudhury of Georgia Tech reported February 14 at the annual meeting of the American Association for the Advancement of Science. She and her colleagues at Microsoft Research in Redmond, Wash., conducted an elaborate study that included a depression screening questionnaire, interviews and an analysis of Facebook activity and interactions of 165 mothers both before and after they had their babies. These women also tend to keep a stiff upper lip on the site, refraining from reporting on their emotional well-being and instead posting objective content geared toward getting feedback or advice on a specific matter, De Choudhury and her colleagues discovered. The scientists also found they could train a computer program to identify which moms had the blues. Such research might help with designing interventions, whereby moms could be warned that they might be sinking into depression and encouraged to reach out for social support or medical attention. M. De Choudhury. Online Social Dynamics and Emotional Wellbeing. American Association for the Advancement of Science Annual Meeting, San Jose, Calif., February 14, 2015. © Society for Science & the Public 2000 - 2015
By Anne Harding NEW YORK (Reuters Health) - Reduced sexual activity could cause a dip in testosterone levels in older men, new findings suggest. Among men 70 and older, those who reported a decline in sexual activity and desire over a two-year period also showed small declines in serum testosterone, Dr. David Handelsman of the ANZAC Research Institute at the University of Sydney and Concord Hospital in New South Wales, Australia, and colleagues found. They report their findings in the Journal of Clinical Endocrinology and Metabolism, online January 28. "Decline in serum testosterone is more likely to be the result rather than the cause of sexual dysfunction among older men who don't have reproductive disorders," Dr. Handelsman told Reuters Health by email. "The widely prevalent misinterpretation of this (as if the mild lowering of serum testosterone needs or might benefit from testosterone treatment) is one of the main drivers of the massive over-use of testosterone prescriptions in North America over the last decade." While declines in androgens and sexual function are both thought to be aging-related, Dr. Handelsman and his colleagues note in their report, the relationship between androgen levels and sexual function is not clear. To better understand the temporal and predictive relationship between androgen levels and sexual function, the researchers looked at 1,226 men participating in the Concord Health and Ageing in Men Project (CHAMP), measuring their levels of testosterone, dihydrotestosterone, estradiol, and estrone with liquid chromatography-tandem mass spectrometry. Men also reported on their sexual function using standardized questions, at baseline and two years later. © 2015 Scientific American
By Nicholas Weiler When you spend your days battling giant squid, it’s good to have friends you can rely on. New research from the Caribbean suggests that female sperm whales (Physeter macrocephalus, pictured) swim with favored companions and form long-term family allegiances. Sperm whales raise their young in communal family groups of about a dozen related females, but mapping out the giant animals' social lives in much detail has been a challenge for scientists. The whales spend 60% of their lives hunting squid hundreds of meters below the waves, and researchers can watch them interact for only a few minutes at a time when they surface to breathe. But a new multiyear study has created the most detailed map yet of sperm whales’ social networks. Between 2005 and 2010, scientists followed nine whale families along the west coast of the Caribbean island of Dominica and mapped their social relationships by counting which females spent the most time together at the surface between dives. As expected, whales mostly preferred to relax with family members, but within families they played favorites, frequently swimming with the same sister, auntie, or aged granny, the researchers report online this week in Animal Behaviour. The network diagram also revealed three pairs of families that mingled frequently over the years to socialize and share babysitting duty. One of these pairs has been fraternizing since 1995, according to data from other researchers, suggesting that such allegiances can last more than a decade. These observations suggest sperm whale families may be similar to the matriarchal clans of elephants, which also form long-lasting family bonds, the researchers say. Further research may determine whether allied families are actually distant cousins and investigate whether whales use signature songs to find their best friends. © 2015 American Association for the Advancement of Science