THE SEXUAL PARADOX
Men, Women, and the Real Gender Gap.
By Susan Pinker.
340 pp. Scribner. $26.
The various excerpts that follow contain research findings that inform the issues discussed occasionally among a small group of humanists in the Bay Area. We are interested in how man-made places reveal the ways that varying values and norms stemming from changing environmental conditions interact with ( i.e., shape or are shaped by) our genetic heritage.
By Karl Zimmer
...When humans mimic others’ faces, in other words, we don’t just go through the motions. We also go through the emotions.
Recently Bernhard Haslinger at the Technical University of Munich realized that he could test the facial feedback theory in a new way. He could temporarily paralyze facial muscles and then scan people’s brains as they tried to make faces. To block facial feedback, Haslinger used Dysport, a Botox-like drug available in Europe.
Botox and Dysport are brand names of a toxin made by the spore-forming bacterium Clostridium botulinum. Botulinum docks on the surface of neurons, blocking the release of a transmitter called acetylcholine. In small amounts botulinum can be fatal. In far, far smaller amounts, it can simply paralyze a small patch of muscles for a few weeks. Haslinger has used Dysport in people with movement disorders like dystonia to help reduce unwanted muscle movement. But Botox and Dysport are best known as treatments to mask aging. Injections into the muscles that make frowns can slow the growth of lines around the eyebrows.
For his brain experiment, Haslinger and his colleagues gave 19 women Dysport injections. Two weeks later the scientists scanned their brains as they showed the women a series of angry or sad faces and asked them either to imitate or just to observe the expressions. Haslinger then ran the same experiment on 19 women without Dysport and compared the two sets of scans.
When the women made sad faces, the same brain regions became active in both those with Dysport and those without. But making angry faces triggered different patterns. In the Dysport-free women, a region known as the amygdala—a key brain region for processing emotions—became active. In the women with Dysport, who could not use their frown muscles, the amygdala was quieter. Haslinger also found another change, in the connections between the amygdala and the brain stem, where signals can trigger many of the feelings that go along with emotions: Dysport made that connection weaker.
Of course neuroscience labs are not the only place where people get shots of Dysport or Botox. According to the American Society of Plastic Surgeons, in the United States doctors administer millions of injections of Botox each year, many of them to people’s faces. Haslinger’s research suggests that this is part of a massive, unplanned experiment.
In June 2008 in the Journal of the American Academy of Dermatology, a team of cosmetic surgeons suggested this experiment is making all of us happier. People with Botox may be less vulnerable to the angry emotions of other people because they themselves can’t make angry or unhappy faces as easily. And because people with Botox can’t spread bad feelings to others via their expressions, people without Botox may be happier too. The surgeons grant that this is just speculation for now. Nevertheless, they declare that “we are left with the tantalizing possibility that cosmetic procedures may have beneficial effects that are more than skin deep.”
Maybe. But for all the Botox youthfulness plastic surgeons may want to think about, neuroscience raises a darker possibility. Making faces helps us understand how other people are feeling. By altering our faces we’re tampering with the ancient lines of communication between face and brain that may change our minds in ways we don’t yet understand.
WHETHER a criminal teenager turns into a violent adult or grows out of crime, may be related to how low his ears are set or the types of food he was given as a child.
International research shows antisocial behaviour in young adults can be written into their genetic code, and made worse by bad parenting.
Indicators that an antisocial child may turn into a life-long violent criminal can be picked up in kindergarten, according to research summarised in this week's New Scientist magazine.
Of the 535 males and 502 females born in New Zealand in 1972 and 1973 who were signed up at birth to the University of Dunedin's Multidisciplinary Health and Development Study, those who dabbled in crime as a teenager can be divided into two clear groups, Terrie Moffitt from the Institute of Psychiatry in London said.
The more common type took up petty crime in adolescence keen to impress "badass" friends, she said.
But the more problematic type had biological predispositions to behaviour problems, the signs of which could be picked up as young as three years of age.
These children - more often boys - tended to have a low IQ, poor language skills, and were often diagnosed with attention-deficit hyperactivity disorder.
Minor physical anomalies such as low-seated ears or furrowed tongues - possibly a sign of poor neural development or damage - could also be signs.
Combined with bad parenting, poverty or abuse, these children were at greater risk of turning to a life-long criminal career, she said.
The early onset group accounted for only 10 per cent of the Dunedin males, but by the age of 26 they had accrued almost half of the violent convictions for the entire study.
Ms Moffitt's study of the Dunedin children also focused on the activity of an enzyme linked to aggression in both animals and humans.
By itself, the activity of the enzyme had little influence, but if the boys were more predisposed to aggression and had suffered some abuse as children they were three times as likely to be diagnosed with conduct disorder in adolescence and 10 times as likely to have been convicted of a violent crime in adulthood.
A US study has found there is a worrying subset of kids within the early onset group who do not react emotionally at all, scoring high in tests used for diagnosing adult psychopathy.
A study at the University of New Orleans found the 30 per cent of early onset antisocial children who showed these traits were most likely to turn to life-long violence.
Children in this group lack empathy and guilt, are thrill-seeking, fearless and narcissistic, says psychopathy expert James Blair from the National Institute of Mental Health in the United States.
Learning to fear punishment or recognise someone else's fear or sadness is difficult for psychopaths, he said.
"If they want something and punching someone in the face is the way to extract it, they might be more likely to engage in that kind of behaviour," he said.
Mr Blair said there are few signs that these psychopathic traits are caused by external factors like poor parenting or abuse, but they could be triggered by social forces like poverty.
The generally accepted approach to tackling the problem of antisocial and violent children is to intervene as young as possible with improved parenting.
Some experts say better parenting could even begin before birth.
A trial of monthly nurse visits throughout pregnancy and until the child's second birthday, in New York in the late 1970s, has been praised by scientists at the University of Colorado.
By the age of 15, the 315 children involved in the trial had only half of the number of arrests, one fifth the number of convictions, smoked and drank less and were less promiscuous than their untreated contemporaries.
In mice, child neglect is a product of both nature and nurture, according to a new study. Writing in the journal PLoS ONE on April 9, researchers from the University of Wisconsin-Madison describe a strain of mice that exhibit unusually high rates of maternal neglect, with approximately one out of every five females failing to care for her offspring.
By comparing the good mothers to their less attentive relatives, the group has found that negligent parenting seems to have both genetic and non-genetic influences, and may be linked to dysregulation of the brain signaling chemical dopamine.
As a possible model for human child neglect, these mice offer a valuable opportunity to investigate the biological and behavioral bases of naturally occurring maternal neglect, say UW-Madison zoology professor Stephen Gammie, who led the study, and co-author psychology professor Anthony Auger.
Good mouse mothers suckle, groom, and protect their pups, while their neglectful sisters may start out trying to care for a litter, but fail to follow through. "There seems to be a switch early on. The neglectful mice may nurse for a day or two after birth, but then the parental care ceases," Gammie says.
To separate the effects of genes and environment, the researchers set up a fostering study, in which pups born to previously nurturing mothers and previously neglectful mothers were switched immediately after birth.
Surprisingly, while nurturing moms attentively cared for foster pups born to other nurturing females, some became more neglectful when given foster pups born to a neglectful mother.
"In some cases the previously nurturing mothers would actively scatter the pups away from the nest, suggesting a negative cue from the pups or a lack of a positive cue," Gammie says. The result suggests that the offspring are somehow able to influence females' behavior and shows that maternal care can be affected by non-genetic factors.
In the fostering study, previously neglectful mothers did successfully raise some of the pups born to previously nurturing mothers, but these surviving pups showed lasting effects, including hyperactivity and low adult body weight. Some females neglected as youngsters were also poor mothers as adults, suggesting some aspects of neglect can be transmitted across generations.
The group also found evidence of genetic factors contributing to neglect. For example, virgin females that exhibited poor self-grooming and hyperactive behavior were at greater risk for becoming neglectful mothers.
To identify possible biological differences, the researchers analyzed brains of neglectful and nurturing mothers shortly after birth. In several brain regions - including some implicated in both maternal behaviors and reward responsiveness - they found higher levels of activity as well as signs of abnormal dopamine signaling in the neglectful mothers.
These patterns suggest that naturally occurring maternal neglect in these mice reflects disrupted reward-seeking behavior, Gammie says. In other words, these females may have the physical capability to take care of their pups, but may lack the proper motivation.
"It's been shown in a number of studies that parental care is a motivated, reward-related behavior," he says. "And it has been suggested by others that some aspects of child neglect in humans could result from a lack of reward of an offspring to the parent."
Though often overshadowed by more visible abuse cases, human child neglect may actually be a more widespread problem. A report published last week by the Centers for Disease Control and Prevention on U.S. children found that, among infants less than a week old, nearly 70 percent of nonfatal mistreatment cases from 2005 to 2006 were instances of neglect.
Child neglect has devastating consequences, Auger says, and the natural occurrence of maternal neglect within this mouse strain offers a powerful opportunity to investigate the biological and behavioral bases of maternal neglect.
Though he cautions that it's too early to know how their findings will translate to humans, for the mice "the difference is quite dramatic in the brain. Dopamine is likely not the only thing being disrupted, but it is an important starting signaling pathway to pursue."
Next, Auger says, "We hope to understand in greater detail the basis of naturally occurring neglect and provide treatment paradigms to these animals to restore natural maternal care of offspring."
Source: University of Wisconsin-Madison
|In 1971, biologists moved five adult pairs of Italian wall lizards from their home island of Pod Kopiste, in the South Adriatic Sea, to the neighboring island of Pod Mrcaru. Now, an international team of researchers has shown that introducing these small, green-backed lizards, Podarcis sicula, to a new environment caused them to undergo rapid and large-scale evolutionary changes.|
"Striking differences in head size and shape, increased bite strength and the development of new structures in the lizard's digestive tracts were noted after only 36 years, which is an extremely short time scale," says Duncan Irschick, a professor of biology at the University of Massachusetts Amherst. "These physical changes have occurred side-by-side with dramatic changes in population density and social structure." Results of the study were published March 25 in Proceedings of the National Academy of Sciences.
Researchers returned to the islands twice a year for three years, in the spring and summer of 2004, 2005 and 2006. Captured lizards were transported to a field laboratory and measured for snout-vent length, head dimensions and body mass. Tail clips taken for DNA analysis confirmed that the Pod Mrcaru lizards were genetically identical to the source population on Pod Kopiste.
Observed changes in head morphology were caused by adaptation to a different food source. According to Irschick, lizards on the barren island of Pod Kopiste were well-suited to catching mobile prey, feasting mainly on insects. Life on Pod Mrcaru, where they had never lived before, offered them an abundant supply of plant foods, including the leaves and stems from native shrubs. Analysis of the stomach contents of lizards on Pod Mrcaru showed that their diet included up to two-thirds plants, depending on the season, a large increase over the population of Pod Kopiste.
"As a result, individuals on Pod Mrcaru have heads that are longer, wider and taller than those on Pod Kopiste, which translates into a big increase in bite force," says Irschick. "Because plants are tough and fibrous, high bite forces allow the lizards to crop smaller pieces from plants, which can help them break down the indigestible cell walls."
Examination of the lizard's digestive tracts revealed something even more surprising. Eating more plants caused the development of new structures called cecal valves, designed to slow the passage of food by creating fermentation chambers in the gut, where microbes can break down the difficult to digest portion of plants. Cecal valves, which were found in hatchlings, juveniles and adults on Pod Mrcaru, have never been reported for this species, including the source population on Pod Kopiste.
"These structures actually occur in less than 1 percent of all known species of scaled reptiles," says Irschick. "Our data shows that evolution of novel structures can occur on extremely short time scales. Cecal valve evolution probably went hand-in-hand with a novel association between the lizards on Pod Mrcaru and microorganisms called nematodes that break down cellulose, which were found in their hindguts."
Change in diet also affected the population density and social structure of the Pod Mrcaru population. Because plants provide a larger and more predictable food supply, there were more lizards in a given area on Pod Mrcaru. Food was obtained through browsing rather than the active pursuit of prey, and the lizards had given up defending territories.
"What is unique about this finding is that rapid evolution can affect not only the structure and function of a species, but also influence behavioral ecology and natural history," says Irschick.
Source: University of Massachusetts Amherst
University of Manchester researchers are investigating why some people remain calm in the face of life's niggles, while others 'flip' with little provocation.
Recent studies using new brain-imaging technology have discovered that a change in the brain's neurochemical activity may be related to increased impulsive aggression (when someone unexpectedly reacts violently with little provocation, as opposed to someone deliberately 'looking for trouble'). Now psychologist Angela Rylands wants to deploy the University's world-leading HRRT PET brain scanner, based at its Wolfson Molecular Imaging Centre (WMIC), as part of a project to find out more.
Angela said: "Positron emission tomography (PET) scanning has revealed that a deficit in brain serotonin neurotransmission may leave some people more prone to aggression and impulse control disorders. I want to establish to what extent such behaviours are rooted at a molecular level and how much does learning from the environment around us also play a part."
One of her case studies, 39-year-old former professional bodyguard turned retail manager Carl Hayes, is available for interview. Carl is taking part in order to find out why he loses his temper so easily (he once set light to £800 in a row with his ex-wife).
Angela is looking for other males aged 18 or over, who do not use illegal drugs, and who feel they may be impulsively aggressive to have their brains scanned, to develop the team's understanding of the processes at work. Genetic samples will also be taken to enable them to investigate any interesting polymorphisms (genetic markers which occur in different forms from person to person), as previous research has implicated specific polymorphisms in aggressive behaviour.
Angela will then carry out psychological assessments of participants' previous exposure to aggression and neuropsychological tests to assess their aggressive capacity.
"It's well known that the prefrontal brain regions are associated with normal social and emotional behaviour, and that people with damage to these areas are more impulsive and aggressive," Angela continued. "We now want to see whether subtle deficits in the brain's serotonin system can explain differing levels of aggression in people who don't have brain damage. Our first theory is that higher capacity for impulsive aggression will be found in those with the lowest levels of brain serotonin. The second is that a combination of our genetic makeup and a harsh or abusive childhood may lead to the brain serotonin system not developing normally.
"The areas of serotonin neurotransmission that we are interested in are in the brain regions associated with inhibitory control. Of course people need to take responsibility for their own behaviour, but it could be that some people have difficulties controlling aggression because of impaired regulation of negative emotions or social behaviour by the serotonin system in their brains.
"The genetic samples we take and our assessments of people's exposure to aggression in their childhoods may uncover the factors that adversely influence the developing serotonin system and lead to a dysfunctional system in the mature adult.
"If we can get to the root of impulsive aggressive behaviour - be it nature, nurture or a combination of the two - it could help us to identify how we can break the cycle of impulsive and aggressive behaviour and intervene with future generations at risk from losing control."
She added: "This work may prevent future generations suffering the consequences of impulsive aggression.
"Aggression that occurs as a consequence of poor impulse control presents a burden for society. Each year over half a million people worldwide die from interpersonal violence. The financial burden of violent crime adds to this, incurring expenditures for the criminal justice system, for the incarceration of offenders and to local victims. Socioeconomic costs and public health issues persist, as a consequence of aggressive behaviour.
"The underpinnings of aggression should be identified to enable advancement towards preventative measures."
Participants will visit the WMIC for a screening session, followed by a scan if appropriate. They will then undergo psychological assessments of their previous exposure to aggression, and neuropsychological tests to assess their aggressive capacity. Volunteers will be reimbursed for their time and travel expenses.
Source: University of Manchester
THE SEXUAL PARADOX
Men, Women, and the Real Gender Gap.
By Susan Pinker.
340 pp. Scribner. $26.
Why do girls on average lead boys for all their years in the classroom, only to fall behind in the workplace? Do girls grow up and lose their edge, while boys mature and gain theirs?
Ten years ago, no one would have thought to ask. The assumption that boys dominated at school as well as at work, while girls were silenced or ignored, seemed beyond dispute. But in her new book, “The Sexual Paradox,” a ringing salvo in the sex-difference wars, Susan Pinker stacks up the evidence of boys’ classroom woes and girls’ triumphs. “In the United States, boys are three times as likely to be placed in special education classes, twice as likely to repeat a grade and a third more likely to drop out of high school,” she writes. Tests of 15-year-olds in 30 European countries show girls far outstripping boys in reading and writing and holding their own in math. Boys are overrepresented in the top 1 percent of math achievers, but there are also more of them at the bottom. A 2006 economics study showed universities practicing affirmative action for men so that superior female applicants wouldn’t swamp them. “If you were to predict the future on the basis of school achievement alone,” Pinker writes, “the world would be a matriarchy.”
And yet, of course, it is not. Once they move from school to work, men on average earn more money and run more shows. They particularly dominate in national government, the corporate boardroom and the science laboratory. Meanwhile, women are more likely to leave the labor force and to end up with lower pay and less authority if they come back.
Pinker, a psychologist and a columnist at The Globe and Mail in Canada, is careful to remind her readers that statistics say nothing about the choices women and men make individually. Nor does she entirely discount the effect of sex discrimination or culture in shaping women’s choices. But she thinks these forces play only a bit part. To support this, Pinker quotes a female Ivy League law professor: “I am very skeptical of the notion that society discourages talented women from becoming scientists,” the professor writes. “My experience, at least from the educational phase of my life, is that the very opposite is true.” If women aren’t racing to the upper echelons of science, government and the corporate world despite decades of efforts to woo them, Pinker argues, then it must be because they are wired to resist the demands at the top of those fields.
Thus, Pinker parks herself firmly among “difference” feminists. Women’s brains aren’t inferior, she argues, but they vary considerably from men’s, and this is the primary explanation for the workplace gender divide. Women care more about intrinsic rewards, they have broader interests, they are more service-oriented and they are better at gauging the effect they have on others. They are “wired for empathy.” These aren’t learned traits; they’re the result of genes and hormones. Beginning in utero, men are generally exposed to higher levels of testosterone, driving them to be more competitive, assertive, vengeful and daring. Women, meanwhile, get a regular dose of oxytocin, which helps them read people’s emotions, “the truest social enabler.” Then there’s prolactin, which, along with oxytocin, surges during pregnancy, breast-feeding and caretaking. Together, the hormones produce such a high that mother rats choose their newborns over cocaine.
Many of the scientific claims are familiar from previous books that pump up findings on sex difference, like “The Female Brain,” by the neurologist Louann Brizendine. Pinker goes even further by drawing a straight line from those blissed-out rats to human mothers who dial back at work. Because of their biological makeup, she argues, most women want to limit the amount of time they spend at work and to find “inherent meaning” there, as opposed to domination. “Both conflict with making lots of money and rising through the ranks,” she points out.
Pinker is surely right to contest what she calls the “vanilla male model” of success — “that women should want what men want and be heartily encouraged to choose it 50 percent of the time.” Or that when employers say jump, employees should always say how high. Even as they work fewer hours for less status and less money, on average, more women report that they are satisfied with their careers. Maybe men might well think the same if more of them felt they could cut back. But Pinker’s difference feminism doesn’t really allow for that possibility. She is a believer: “The puzzle is why the idea of sex differences continues to be so controversial,” she writes.
In her zeal, Pinker veers to the onesided. She doesn’t acknowledge that some of the research cited in her footnotes is either highly questionable as social science (Louise Story’s 2005 article in The New York Times, for instance, about her survey of Ivy League women’s aspirations) or has never been replicated — like the findings from Simon Baron-Cohen’s laboratory that newborn girls showed more interest in looking at human faces, while newborn boys preferred mechanical mobiles. Pinker omits the work of scientists who have shown that sex-based brain differences pale in comparison to similarities. We shouldn’t wish the role of sex differences away because they’re at odds with feminist dogma. But that doesn’t mean we should settle for the reductionist version of the relevant science, even if the complexity doesn’t make for as neat a package between hard covers.
Pinker also doesn’t acknowledge that some scientists wouldn’t accept the premise behind her chapters about male fragility. She cites men with Asperger’s syndrome and attention deficit disorder as examples of what she calls the “extreme male brain.” These men are train wrecks in school but then get on track in adulthood, when they can focus singlemindedly on their chosen fields. Pinker argues that their experience helps explain the general male lag at school and jump ahead at work. It’s true that men are more likely than women to suffer from Asperger’s and from some forms of A.D.D. But do their particular outsize talents and deficits really shed light on the workings of the average man’s brain? That question is hardly settled, and Pinker seems a bit glib when she fails to say as much.
Pinker also skips past an answer to the book’s central question that may have more explanatory power than her other arguments, even if it’s more prosaic and familiar to many a parent. Boys lag dramatically behind girls in terms of psychological development and physical resilience and then start to catch up as teenagers, as a long-running and wellknown study Pinker cites documented. Maybe after a few years as girls’ developmental equals, boys are ready to compete in the work force — and then zoom ahead as cultural norms and discrimination push women back. After all, why would girls’ hard-wired predilection against competition stay on ice while they blithely sweep all the academic honors and then kick in only at work?
Despite such unanswered questions, Pinker deserves credit for hacking away at the vanilla male model. She is right to point out that “grueling hours do not always translate into productivity” and to seethe at employers for ratcheting up their demands “even while extolling the virtues of gender balance.” And she is also right to call on schools to give the troubles of boys a fair share of attention. Pinker may not convey all the complexity that goes into making many men’s and women’s lives different, but she has a good prescription for helping more of us be our best selves.
Emily Bazelon is a senior editor at Slate.