XYY syndrome is an aneuploidy (abnormal number) of the sex chromosomes in which a human male receives an extra Y-chromosome.

Some medical geneticists question whether the term “syndrome” is appropriate for this condition because its clinical phenotype is normal and the vast majority (an estimated 97% in Britain) of 47,XYY males do not know their karyotype.

{ Wikipedia | Continue reading }

Triple X syndrome is a form of chromosomal variation characterized by the presence of an extra X chromosome in each cell of a human female. The condition occurs only in females. […]

Because of the lyonization, inactivation, and formation of a Barr body in all female cells, only one X chromosome is active at any time. Thus, Triple X syndrome most often has only mild effects, or has no unusual effects at all.

Symptoms may include tall stature; small head (microcephaly); vertical skinfolds that may cover the inner corners of the eyes (epicanthal folds); delayed development of certain motor skills, speech and language; learning disabilities, such as dyslexia; or weak muscle tone.

{ Wikipedia | Continue reading }

Klinefelter syndrome, or XXY syndrome, is a genetic disorder in which there is at least one extra X chromosome to a standard human male karyotype, for a total of 47 chromosomes rather than the 46 found in genetically normal humans. […]

This chromosome constitution exists in roughly between 1:500 to 1:1000 live male births but many of these people may not show symptoms. […]

Affected males are often infertile, or may have reduced fertility. […] XXY males are also more likely than other men to have certain health problems, which typically affect females, such as breast cancer and osteoporosis.

{ Wikipedia | Continue reading }

photos { Frieke Janssens }

On the evening of August 13, 1967, two women were attacked and killed by grizzly bears (Ursus arctos horribilis) in separate incidents within Glacier National Park (GNP). Following these incidents, there was speculation that due to odors associated with menstruation, women may be more prone to attack by bears than are men (Rogers et al. 1991).


In a study designed to test the hypothesis that bears are attracted to the odors of menstruation, Cushing (1983) reported that when presented with a series of different odors (including seal scents, other food scents, non menstrual human blood, and used tampons), four captive polar bears elicited a strong behavioral response only to seal scents and menstrual odors (used tampons).

Herrero (1985) analyzed the circumstances of hundreds of grizzly bear attacks on humans, including the attacks on the two women in GNP, and concluded that there was no evidence linking menstruation to any of the attacks. The responses of grizzly bears to menstrual odors has not been studied experimentally.

[…]

Menstrual odors were essentially ignored by black bears of all sex and age classes.

{ Bearman’s | Continue reading | Thanks Tim! }

Most sleeping pills are designed to knock you out for eight hours. When the Food and Drug Administration was evaluating a new short-acting pill for people to take when they wake up in the middle of the night, agency scientists wanted to know how much of the drug would still be in users’ systems come morning.

Blood tests uncovered a gender gap: Men metabolized the drug, Intermezzo, faster than women. Ultimately the F.D.A. approved a 3.5 milligram pill for men, and a 1.75 milligram pill for women.

The active ingredient in Intermezzo, zolpidem, is used in many other sleeping aids, including Ambien. But it wasn’t until earlier this month that the F.D.A. reduced doses of Ambien for women by half.

Sleeping pills are hardly the only medications that may have unexpected, even dangerous, effects in women. Studies have shown that women respond differently than men to many drugs, from aspirin to anesthesia. Researchers are only beginning to understand the scope of the issue, but many believe that as a result, women experience a disproportionate share of adverse, often more severe, side effects. […]

Until 1993, women of childbearing age were routinely excluded from trials of new drugs. When the F.D.A. lifted the ban that year, agency researchers noted that because landmark studies on aspirin in heart disease and stroke had not included women, the scientific community was left “with doubts about whether aspirin was, in fact, effective in women for these indications.” […]

Women also react differently to alcohol, tobacco and cocaine, studies have found.

It’s not just because women tend to be smaller than men. Women metabolize drugs differently because they have a higher percentage of body fat and experience hormonal fluctuations and the monthly menstrual cycle. “Some drugs are more water-based and like to hang out in the blood, and some like to hang out in the fat tissue,” said Wesley Lindsey, assistant professor of pharmacy practice at Auburn University, who is a co-author of a paper on sex-based differences in drug activity.

{ NY Times | Continue reading }

Far more insidious is the insistence by some feminists on mocking transsexual women and denying their existence.

The word that annoys these so-called feminists most is ‘cis’, or ‘cissexual’. This is a term coined in recent years to refer to people who are not transsexual. The response is instant and vicious: “we’re not cissexual, we’re normal - we don’t want to be associated with you freaks!” Funnily enough, that’s just the kind of pissing and whining that a lot of straight people came out with when the term ‘heterosexual’ first began to be used as an antonym of ‘homosexual.’  Don’t call us ‘heterosexuals’, they said - we’re normal, and you don’t belong.

{ Laurie Penny | Continue reading | via Nathan/Zungu Zungu }

art { Astrid Klein }

Evolutionary psychologists who study mating behavior often begin with a hypothesis about how modern humans mate: say, that men think about sex more than women do. Then they gather evidence — from studies, statistics and surveys — to support that assumption. Finally, and here’s where the leap occurs, they construct an evolutionary theory to explain why men think about sex more than women, where that gender difference came from, what adaptive purpose it served in antiquity, and why we’re stuck with the consequences today.

Lately, however, a new cohort of scientists have been challenging the very existence of the gender differences in sexual behavior that Darwinians have spent the past 40 years trying to explain and justify on evolutionary grounds. […]

Everyone has always assumed — and early research had shown — that women desired fewer sexual partners over a lifetime than men. But in 2003, two behavioral psychologists, Michele G. Alexander and Terri D. Fisher, published the results of a study that used a “bogus pipeline” — a fake lie detector. When asked about actual sexual partners, rather than just theoretical desires, the participants who were not attached to the fake lie detector displayed typical gender differences. Men reported having had more sexual partners than women. But when participants believed that lies about their sexual history would be revealed by the fake lie detector, gender differences in reported sexual partners vanished. In fact, women reported slightly more sexual partners (a mean of 4.4) than did men (a mean of 4.0).

In 2009, another long-assumed gender difference in mating — that women are choosier than men — also came under siege. In speed dating, as in life, the social norm instructs women to sit in one place, waiting to be approached, while the men rotate tables. But in one study of speed-dating behavior, the evolutionary psychologists Eli J. Finkel and Paul W. Eastwick switched the “rotator” role. The men remained seated and the women rotated. By manipulating this component of the gender script, the researchers discovered that women became less selective — they behaved more like stereotypical men — while men were more selective and behaved more like stereotypical women. The mere act of physically approaching a potential romantic partner, they argued, engendered more favorable assessments of that person.

Recently, a third pillar appeared to fall. To back up the assumption that an enormous gap exists between men’s and women’s attitudes toward casual sex, evolutionary psychologists typically cite a classic study published in 1989. Men and women on a college campus were approached in public and propositioned with offers of casual sex by “confederates” who worked for the study. The confederate would say: “I have been noticing you around campus and I find you to be very attractive.” The confederate would then ask one of three questions: (1) “Would you go out with me tonight?” (2) “Would you come over to my apartment tonight?” or (3) “Would you go to bed with me tonight?”

Roughly equal numbers of men and women agreed to the date. But women were much less likely to agree to go to the confederate’s apartment. As for going to bed with the confederate, zero women said yes, while about 70 percent of males agreed.

Those results seemed definitive — until a few years ago, when Terri D. Conley, a psychologist at the University of Michigan, set out to re-examine what she calls “one of the largest documented sexuality gender differences,” that men have a greater interest in casual sex than women.

Ms. Conley found the methodology of the 1989 paper to be less than ideal. “No one really comes up to you in the middle of the quad and asks, ‘Will you have sex with me?’ ” she told me recently. “So there needs to be a context for it. If you ask people what they would do in a specific situation, that’s a far more accurate way of getting responses.” In her study, when men and women considered offers of casual sex from famous people, or offers from close friends whom they were told were good in bed, the gender differences in acceptance of casual-sex proposals evaporated nearly to zero.

{ NY Times | Continue reading }

photo { George Brassaï }

As the percentage of wives outearning their husbands grows, the traditional social norm of the male breadwinner is challenged. The upward income comparison of the husband may cause psychological distress that affects both partners’ mental and physical health in ways that impact decisions on marriage, divorce, and careers. This paper studies this impact through sexual and mental health problems. Using wage and prescription medication data from Denmark, we implement a regression discontinuity design to show that men outearned by their wives are more likely to use erectile dysfunction (ED) medication than their male breadwinner counterparts, even when this inequality is small. Breadwinner wives suffer increased insomnia/anxiety medication usage, with similar effects for men. We find no effects for unmarried couples or for men who earned less than their fiancée prior to marriage. Our results suggest that social norms play important roles in dictating how individuals respond to upward social comparisons.

{ Personality and Social Psychology Bulletin/SSRN | Continue reading }

Uptalk is the use of a rising, questioning intonation when making a statement, which has become quite prevalent in contemporary American speech. Women tend to use uptalk more frequently than men do, though the reasons behind this difference are contested. I use the popular game show Jeopardy! to study variation in the use of uptalk among the contestants’ responses, and argue that uptalk is a key way in which gender is constructed through interaction. While overall, Jeopardy! contestants use uptalk 37 percent of the time, there is much variation in the use of uptalk. The typical purveyor of uptalk is white, young, and female. Men use uptalk more when surrounded by women contestants, and when correcting a woman contestant after she makes an incorrect response. Success on the show produces different results for men and women. The more successful a man is, the less likely he is to use uptalk; the more successful a woman is, the more likely she is to use uptalk.

{ SAGE }

photo { Billy Kidd }

{ In humans the secondary sex ratio (i.e., at birth) is commonly assumed to be 105 boys to 100 girls, an assumption that is a subject of debate in the scientific community. The sex ratio for the entire world population is 101 males to 100 females. | Wikipedia | Continue reading }

In both the lab and the field, female subjects tend to show greater confidence in their groups than in themselves, while male subjects show greater confidence in themselves than in their groups.

{ PDF | via OvercomingBias }

photos { Joseph Cultice }

Cerebral cortex has a very large number of testosterone receptors, which could be a basis for sex differences in sensory functions. For example, audition has clear sex differences, which are related to serum testosterone levels. Of all major sensory systems only vision has not been examined for sex differences, which is surprising because occipital lobe (primary visual projection area) may have the highest density of testosterone receptors in the cortex. We have examined a basic visual function: spatial and temporal pattern resolution and acuity. […]

Across the entire spatio-temporal domain, males were more sensitive, especially at higher spatial frequencies; similarly males had significantly better acuity at all temporal rates. […]

We suggest that testosterone plays a major role, leading to different connectivities in males and in females. But, for whatever reasons, we find that males have significantly greater sensitivity for fine detail and for rapidly moving stimuli. One interpretation is that this is consistent with sex roles in hunter-gatherer societies.

{ Biology of Sex Differences/NCBI | Continue reading }

We examined the possible sex differences in color appearance of monochromatic lights across the visible spectrum. There is a history of men and women perceiving color differently. However, all of these studies deal with higher cognitive functions which may be culture-biased. We study basic visual functions, such as color appearance, without reference to any objects. […]

There were relatively small but clear and significant, differences between males and females in the hue sensations elicited by almost the entire spectrum. Generally, males required a slightly longer wavelength to experience the same hue as did females.

{ Biology of Sex Differences | PDF }

image { Jaymes Sinclair }

Kathryn Graham and her colleagues trained 148 observers and sent them out to 118 bars in early-hours Toronto where they recorded 1,057 instances of aggression from 1,334 visits. Where the majority of psychology research on aggression is based on laboratory simulations, Graham’s team collected real-life observational data to find out who gets aggressive and why.

The researchers followed the Theory of Coercive Actions, according to which aggressive acts have one or more motives: compliance (getting someone to do something, or stop doing something); grievance; social identity (to prove one’s status and power); and thrill-seeking.

Unsurprisingly, the vast majority (77.5 per cent) of aggressive acts were instigated by men. Men more than women were driven to aggression by identity and thrill-seeking motives; by contrast female aggression was more often motivated by compliance and grievance. This often had a defensive intent, as a reaction against unwanted sexual advances. […]

The researchers found that greater intoxication led to more serious aggression in women, but not men - perhaps because the latter were emboldened enough already.

{ BPS | Continue reading }

According to an influential and controversial theory, autism is the manifestation of an “Extreme Male Brain.” The reasoning goes something like this - the condition is far more prevalent in males than females; people with autism think in a distinctive style that’s more commonly observed in men than women (that is, high in systematising and low in empathising); and greater testosterone exposure in the womb appears to go hand in hand with an infant exhibiting more autism-like traits in later childhood.

Simon Baron-Cohen, the psychologist who first proposed the theory, always conjectured that there may also be such a thing as an “Extreme Female Brain.” Now in a new paper, a pair of researchers in the USA have made the case that the Extreme Female Brain exists, it’s highly empathic, and it comes with its own problematic consequences, in terms of a fear of negative evaluation by others, and related to that, a greater risk of eating disorders (which are known to be far more prevalent in women than men).

{ BPS | Continue reading }

photo { Andrew Miksys }

Castration had a huge effect on the lifespans of Korean men, according to an analysis of hundreds of years of eunuch “family” records.

They lived up to 19 years longer than uncastrated men from the same social class and even outlived members of the royal family.

The researchers believe the findings show male hormones shorten life expectancy.

{ BBC | Continue reading }

New research traces the dramatic rise in feminine pronouns in books over the past century.

Using the Google Books database, the researchers examined the ratio of male pronouns (he, him, his, himself) to female ones (she, her, hers, herself) in the texts of 1.2 million books published in the U.S. between 1900 and 2008. They suspected feminine references would represent a larger percentage of such words over time, as women gained in power and status.

They were right. But there were periods of regression, and a real shift didn’t occur until the late 1960s.

{ Pacific Standard | Continue reading }

To be a ‘success’ in evolutionary terms, women need to have access to resources for raising offspring, and men need to have access to fertile females. Researchers have argued that women tend to prefer partners who have an ability to invest resources in their children (i.e., wealthy men), and men tend to prefer partners who appear fertile (i.e., young women) because evolutionary adaptations have programmed these preferences in our brains.

But in the modern world, ‘success’ is not necessarily tied to offspring, so researchers […] hypothesized that the influence of evolutionary biases on mate choice would decline proportionally with nations’ gender parity, or the equality between men and women. […] They found that the gender difference in mate preferences predicted by evolutionary psychology models “is highest in gender-unequal societies, and smallest in the most gender-equal societies,” according to Zentner.

{ APS | Continue reading }

As noted in a previous posting, a number of studies have found that males outperform females on tests of general knowledge. The reasons for this are not yet clear. Women’s poorer test performance could be because they actually have acquired less knowledge than men, or it could be that they are not accessing all the knowledge they have. […]

Sex differences in general knowledge favouring males that were identified in a number of studies have been attributed to differing interests between men and women rather than differences in ability.

Another possibility that has not been explored in the research literature is that stereotype threat could have a detrimental effect on the performance of females in tests. […] For example, women who are reminded of their female identity perform more poorly on maths tests compared to a control group.

{ Eye on Psych | Continue reading }

The way that the visual centers of men and women’s brains works is different, finds new research published in BioMed Central’s open access journal Biology of Sex Differences. Men have greater sensitivity to fine detail and rapidly moving stimuli, but women are better at discriminating between colors.

{ EurekAlert | Continue reading }

In many restaurants throughout the world, wait staff’s income depends largely on the tips received from customers. According to this study, male restaurant customers give higher tips to waitresses wearing red. […]

Men gave between 14.6% and 26.1% more to waitresses wearing red, while color had no effect on female patrons’ tipping behavior at all.

{ SAGE | Continue reading }

photo { Nick Meek }

Previous research on gender effects in robots has largely ignored the role of facial cues. We fill this gap in the literature by experimentally investigating the effects of facial gender cues on stereotypical trait and application ascriptions to robots. As predicted, the short-haired male robot was perceived as more agentic than was the long-haired female robot, whereas the female robot was perceived as more communal than was the male counterpart. Analogously, stereotypically male tasks were perceived more suitable for the male robot, relative to the female robot, and vice versa.

{ Journal of Applied Social Psychology | via Mind Hacks }

photo { Barbara Crane }

Sex differences in relationship regret: The role of perceived mate characteristics

[…]

Regret reported by men in both study 1 and study 2 varied as a function of the perceived attractiveness of the participants’ actual and potential mate. Regret reported by women in study 2 varied as a function of the perceived stinginess of the participant’s mate and perceived wealth of the participants’ potential mate. Study 3 found that sex differences in type of regret (with men regretting inaction more than women) occurred only when the mate presented in the scenario was described in ways consistent with mate preferences. Together these findings suggest that regret differs between the sexes in ways consistent with sex differences in mate preferences.

{ Evolutionary Psychology | Continue reading }

In a new study published in the journal Vision Research, researchers at the University of Southern California show that the eyes and attention of men and women meander in distinctly different ways. […]

Men, when focused on the person being interviewed, parked their eyes on the speaker’s mouth. They tended to be most distracted by distinctive movement behind the interview subjects.

By contrast, women shift their focus between the interview subject’s eyes and body. When they were distracted, it was typically by other people entering the video frame.

{ EurekAlert | Continue reading }

photo { Henry Wessel }