Same-sex marriage legalization reduced implicit and explicit antigay bias

Interesting work from Ofosu et al. shows how government legislation can inform individuals’ attitudes, even when these attitudes may be deeply entrenched and socially and politically volatile.:

The current research tested whether the passing of government legislation, signaling the prevailing attitudes of the local majority, was associated with changes in citizens’ attitudes. Specifically, with ∼1 million responses over a 12-y window, we tested whether state-by-state same-sex marriage legislation was associated with decreases in antigay implicit and explicit bias. Results across five operationalizations consistently provide support for this possibility. Both implicit and explicit bias were decreasing before same-sex marriage legalization, but decreased at a sharper rate following legalization. Moderating this effect was whether states passed legislation locally. Although states passing legislation experienced a greater decrease in bias following legislation, states that never passed legislation demonstrated increased antigay bias following federal legalization. Our work highlights how government legislation can inform individuals’ attitudes, even when these attitudes may be deeply entrenched and socially and politically volatile.

The life prospects of female co-twins are diminished by prenatal testosterone from their male twins.

From Bütikofe et al.:

During sensitive periods in utero, gonadal steroids help organize biological sex differences in humans and other mammals. In litter-bearing species, chromosomal females passively exposed to prenatal testosterone from male littermates exhibit altered physical and behavioral traits as adults. The consequences of such effects are less well understood in humans, but recent near-doubling of twinning rates in many countries since 1980, secondary to advanced maternal age and increased reliance on in vitro fertilization, means that an increasing subset of females in many populations may be exposed to prenatal testosterone from their male co-twin. Here we use data on all births in Norway (n = 728,842, including 13,800 twins) between 1967 and 1978 to show that females exposed in utero to a male co-twin have a decreased probability of graduating from high school (15.2%), completing college (3.9%), and being married (11.7%), and have lower fertility (5.8%) and life-cycle earnings (8.6%). These relationships remain unchanged among the subsets of 583 and 239 females whose male co-twin died during the first postnatal year and first 28 days of life, respectively, supporting the interpretation that they are due primarily to prenatal exposure rather than to postnatal socialization effects of being raised with a male sibling. Our findings provide empirical evidence, using objectively measured nation-level data, that human females exposed prenatally to a male co-twin experience long-term changes in marriage, fertility, and human capital. These findings support the hypothesis of in utero testosterone transfer between twins, which is likely affecting a small but growing subset of females worldwide.

Parents mention sons more often than daughters on social media.

From Sivak and Smirnov:

Significance

Parents’ preference for sons is a well-known phenomenon. This study examines whether the use of social media by parents is gender biased. Due to the large-scale use of social media, even a moderate bias might significantly contribute to gender inequality. We use data from a Russian social networking site on posts made by 635,665 users and find that parents mention sons more often than daughters and that posts featuring sons get more “likes.” This gender imbalance may send a message that girls are less important than boys or that they deserve less attention. Particularly in a country with an above-average ranking on gender parity, this invisible bias might present an intractable obstacle to gender equality.

Abstract

Gender inequality starts early in life. Parents tend to prefer boys over girls, which is manifested in reproductive behavior, marital life, and parents’ pastimes and investments in their children. While social media and sharing information about children (so-called “sharenting”) have become an integral part of parenthood, whether and how gender preference shapes the online behavior of users are not well known. In this paper we use public posts made by 635,665 users from Saint Petersburg on a popular Russian social networking site, to investigate public mentions of daughters and sons on social media. We find that both men and women mention sons more often than daughters in their posts. We also find that posts featuring sons receive more “likes” on average. Our results indicate that girls are underrepresented in parents’ digital narratives about their children, in a country with an above-average ranking on gender parity. This gender imbalance may send a message that girls are less important than boys or that they deserve less attention, thus reinforcing gender inequality from an early age.

Successes of advantaged group members get more attention.

Kteily et al. show how political ideology shapes the amplification of the accomplishments of disadvantaged vs. advantaged group members:

Significance

Inequality prospers when successes of advantaged group members (e.g., men, whites) get more attention than equivalent successes of disadvantaged group members (e.g., women, blacks). What determines whose successes individuals deem worth promoting vs. those they ignore? Using hundreds of thousands of tweets from the 2016 Olympics, we show that liberals are much more likely than conservatives to shine a spotlight on black and female (vs. white and male) US gold medalists. Two further experiments provide evidence that such differential amplification of successful targets is driven by a motivation—higher among liberals—to raise disadvantaged groups’ standing in service of equality. We find that liberals drive differential amplification more than conservatives and establish a behavioral mechanism through which liberals’ egalitarian motives manifest.

Abstract

Recent years have witnessed an increased public outcry in certain quarters about a perceived lack of attention given to successful members of disadvantaged groups relative to equally meritorious members of advantaged groups, exemplified by social media campaigns centered around hashtags, such as #OscarsSoWhite and #WomenAlsoKnowStuff. Focusing on political ideology, we investigate here whether individuals differentially amplify successful targets depending on whether these targets belong to disadvantaged or advantaged groups, behavior that could help alleviate or entrench group-based disparities. Study 1 examines over 500,000 tweets from over 160,000 Twitter users about 46 unambiguously successful targets varying in race (white, black) and gender (male, female): American gold medalists from the 2016 Olympics. Leveraging advances in computational social science, we identify tweeters’ political ideology, race, and gender. Tweets from political liberals were much more likely than those from conservatives to be about successful black (vs. white) and female (vs. male) gold medalists (and especially black females), controlling for tweeters’ own race and gender, and even when tweeters themselves were white or male (i.e., advantaged group members). Studies 2 and 3 provided experimental evidence that liberals are more likely than conservatives to differentially amplify successful members of disadvantaged (vs. advantaged) groups and suggested that this is driven by liberals’ heightened concern with social equality. Addressing theorizing about ideological asymmetries, we observed that political liberals are more responsible than conservatives for differential amplification. Our results highlight ideology’s polarizing power to shape even whose accomplishments we promote, and extend theorizing about behavioral manifestations of egalitarian motives.

Stop talking about 'male' and 'female' brains.

As a counterpoint to yesterday's post, which invokes the Extreme Male Brain theory of autism, I pass on some clips from a piece by Joel and Fine that contests this categorization...

Consider, for example, Cambridge University psychologist Simon Baron-Cohen’s influential Empathizing-Systemizing theory of brains and the accompanying “extreme male brain” theory of autism. This presupposes there is a particular “systemizing” brain type that we could meaningfully describe as “the male brain,” that drives ways of thinking, feeling, and behaving that distinguish the typical boy and man from the typical “empathizing” girl and woman.

...one of us, Daphna Joel, led an analysis of four large data sets of brain scans, and found that the sex differences you see overall between men’s and women’s brains aren’t neatly and consistently seen in individual brains. In other words, humans generally don’t have brains with mostly or exclusively “female-typical” features or “male-typical” features. Instead, what’s most common in both females and males are brains with “mosaics” of features, some of them more common in males and some more common in females.

...Joel and colleagues then applied the same kind of analysis to large data sets of psychological variables, to ask: Do sex differences in personality characteristics, attitudes, preferences, and behaviors add up in a consistent way to create two types of humans, each with its own set of psychological features? The answer, again, was no: As for brain structure, the differences created mosaics of feminine and masculine personality traits, attitudes, interests, and behaviors...what was typical of both men and women (70 percent of them, to be exact) was a mosaic of feminine and masculine characteristics.

...if autism is indeed more prevalent in males, this may be associated with a difference between the sexes in the odds that a rare combination of brain characteristics makes an appearance, rather than with the typical male brain being a little more “autistic" than the typical female brain. Indeed, a recent study found that males with autism spectrum disorder had an atypical combination of “female-like” and “male-like” brain activity patterns.

The key point here is that although there are sex differences in brain and behavior, when you move away from group-level differences in single features and focus at the level of the individual brain or person, you find that the differences, regardless of their origins, usually “mix up” rather than “add up.” (The reason for this mixing-up of characteristics is that the genetic and hormonal effects of sex on brain and behavior depend on, and interact with, many other factors.) This yields many types of brain and behavior, which neither fall into a “male” and a “female” type, nor line up tidily along a male-female continuum.

The claim that science tells us that the possibility of greater merging of gender roles is unlikely because of “natural” differences between the sexes, focuses on average sex differences in the population — often in combination with the implicit assumption that whatever we think men are “more” of, is what is most valuable for male-dominated roles. (Why else would organizations offer confidence workshops for women, rather than modesty training for men?) But the world is inhabited by individuals whose unique mosaics of characteristics can’t be predicted on the basis of their sex. So let’s keep working on overcoming gender stereotypes, bias, discrimination, and structural barriers before concluding that sex, despite being a poor guide to our brains and psychological characteristics, is a strong determinant of social structure.

DNA variants linked to same sex behavior.

Michael Price and Jocelyn Kaiser report from the annual meeting of the American Society of Human Genetics in San Diego:

How genes influence sexual orientation has sparked debate for at least a quarter-century. But geneticists have had only a handful of underpowered studies to address a complex, fraught, and often stigmatized area of human behavior. Now, the largest-ever study of the genetics of sexual orientation has revealed four genetic variants strongly associated with what the researchers call nonheterosexual behavior. Some geneticists are hailing the findings as a cautious but significant step in understanding the role of genes in sexuality. Others question the wisdom of asking the question in the first place.

Andrea Ganna, a research fellow with the Broad Institute in Cambridge, Massachusetts, and Harvard Medical School in Boston, and colleagues examined data from hundreds of thousands of people who provided both DNA and behavioral information to two large genetic surveys, the UK Biobank study and the private genetics firm 23andMe. They analyzed DNA markers from people who answered either “yes” or “no” to the question, “Have you ever had sex with someone of the same sex?” In total, they identified 450,939 people who said their sexual relationships had been exclusively heterosexual and 26,890 people who reported at least one homosexual experience.

In Ganna’s talk yesterday at the annual meeting of the American Society of Human Genetics here, he emphasized that the researchers were cautious about exploring sexual behavior that is still illegal in many countries, and that they tried to frame their questions carefully “to avoid a fishing expedition.” The team, which includes behavioral scientists, preregistered their research design and also met regularly with members of the lesbian, gay, bisexual, transgender, or questioning (LGBTQ) community to discuss and share results. Ganna acknowledged that what they call “nonheterosexual behavior” includes “a large spectrum of sexual experiences, that go from people who engage exclusively in same-sex behavior to those who might have experimented once or twice.”

The researchers performed a genome-wide association study (GWAS) in which they looked for specific variations in DNA that were more common in people who reported at least one same-sex sexual experience. They identified four such variants on chromosomes seven, 11, 12, and 15, respectively.

Two variants were specific to men who reported same-sex sexual experience. One, a cluster of DNA on chromosome 15, has previously been found to predict male-pattern baldness. Another variant on chromosome 11 sits in a region rich with olfactory receptors. Ganna noted that olfaction is thought to play a large role in sexual attraction.

A much smaller 1993 study, which used a different kind of association technique known as a genetic linkage study, had suggested a stretch of DNA on the X chromosome was linked to inherited homosexuality. In the new GWAS, that stretch was not found to be associated with the reported same-sex behavior. But the lead author of the earlier study, Dean Hamer, then of the National Institutes of Health in Bethesda, Maryland, praised the new work. “It's important that attention is finally being paid [to the genetics of sexual orientation] with big sample sizes and solid institutions and people,” he said. “This is exactly the study we would have liked to have done in 1993.”

The four newly identified genetic variants also were correlated with some mood and mental health disorders. Both men and women with the variants were more likely to have experienced major depressive disorder and schizophrenia, and women were more likely to have bipolar disorder. Ganna stressed that these findings should not be taken to mean that the variants cause the disorders. Instead, it “might be because individuals who engaged in nonheterosexual behavior are more likely to be discriminated [against], and are more likely to develop depression,” he said.

Ganna noted that the correlation with schizophrenia and risk-taking behavior was more pronounced in the UK Biobank participants, who tend to skew older than those in the 23andMe group. That could be because older generations faced more sexual discrimination than younger ones, Ganna said, noting that environment likely plays a significant role in which traits wind up correlating with sexual orientation.

Overall, he said the findings reinforce the idea that human sexual behavior is complex and can’t be pinned on any simple constellation of DNA. “I’m pleased to announce there is no ‘gay gene,’” Ganna said. “Rather, ‘nonheterosexuality’ is in part influenced by many tiny genetic effects.” Ganna told Science that researchers have yet to tie the genetic variants to actual genes, and it’s not even clear whether they sit within coding or noncoding stretches of DNA. Trying to pin down exactly what these DNA regions do will be among the team’s difficult next steps.

“It’s an intriguing signal,” he said. “We know almost nothing about the genetics of sexual behavior, so anywhere is a good place to start.”..He added that the four genetic variants could not reliably predict someone’s sexual orientation. “There’s really no predictive power,” he said.

Given the complexity of human sexual behavior, much of which is not captured in the study questions, biomedical informatics graduate student Nicole Ferraro from Stanford University in Palo Alto, California, questioned the work’s utility. She and fellow biomedical sciences grad student Kameron Rodrigues said the study didn’t do enough to explore the nuances of how one’s sexual identity differs from sexual behavior, and they worried that the study could be used to stigmatize members of the LGBTQ community. “It just seems like there’s no benefit that can come from this kind of study, only harm,” Rodrigues said.

The abstract for Ganna’s talk referenced another provocative result: Heterosexual people who possess these same four genetic variants tend to have more sexual partners, suggesting associated genes might confer some mating advantage for heterosexuals. That could help explain why these variants might stick around in populations even if people attracted to the same sex tend to have fewer children than heterosexuals. Ganna did not touch on that finding in his talk, citing lack of time.

That was probably a wise choice, geneticist Chris Cotsapas at the Yale School of Medicine said, because the evolutionary implications haven’t been firmed up. “People are going to oversimplify it to say, ‘Gay genes help straight people have more sex,’ and it’s really not that simple,” he said.

Overall, the findings were “very carefully, cautiously presented,” Cotsapas said, and represent a good start for geneticists charting the complexities of human sexuality.

Income inequality drives female sexualization.

Blake et al. do a fascinating analysis that suggests that rising economic inequality promotes status competition among women, by means of the posting of "sexy selfies." The prevalence of sexy selfies is greatest in environments characterized by highly unequal incomes.

Significance

Female sexualization is increasing, and scholars are divided on whether this trend reflects a form of gendered oppression or an expression of female competitiveness. Here, we proxy local status competition with income inequality, showing that female sexualization and physical appearance enhancement are most prevalent in environments that are economically unequal. We found no association with gender oppression. Exploratory analyses show that the association between economic inequality and sexualization is stronger in developed nations. Our findings have important implications: Sexualization manifests in response to economic conditions but does not covary with female subordination. These results raise the possibility that sexualization may be a marker of social climbing among women that track the degree of status competition in the local environment.

Abstract

Publicly displayed, sexualized depictions of women have proliferated, enabled by new communication technologies, including the internet and mobile devices. These depictions are often claimed to be outcomes of a culture of gender inequality and female oppression, but, paradoxically, recent rises in sexualization are most notable in societies that have made strong progress toward gender parity. Few empirical tests of the relation between gender inequality and sexualization exist, and there are even fewer tests of alternative hypotheses. We examined aggregate patterns in 68,562 sexualized self-portrait photographs (“sexy selfies”) shared publicly on Twitter and Instagram and their association with city-, county-, and cross-national indicators of gender inequality. We then investigated the association between sexy-selfie prevalence and income inequality, positing that sexualization—a marker of high female competition—is greater in environments in which incomes are unequal and people are preoccupied with relative social standing. Among 5,567 US cities and 1,622 US counties, areas with relatively more sexy selfies were more economically unequal but not more gender oppressive. A complementary pattern emerged cross-nationally (113 nations): Income inequality positively covaried with sexy-selfie prevalence, particularly within more developed nations. To externally validate our findings, we investigated and confirmed that economically unequal (but not gender-oppressive) areas in the United States also had greater aggregate sales in goods and services related to female physical appearance enhancement (beauty salons and women’s clothing). Here, we provide an empirical understanding of what female sexualization reflects in societies and why it proliferates.

No gender differences in early math cognition.

Kersey et al. have examined data from more than 500 children ranging in age from 6 months to 8 years across several tests of numerosity, counting, and elementary mathematics concepts. They found no differences in mathematical performance between boys and girls in any of the ages tested, suggesting that gender differences in STEM representation are unlikely to be due to intrinsic differences in cognitive ability.

Recent public discussions have suggested that the under-representation of women in science and mathematics careers can be traced back to intrinsic differences in aptitude. However, true gender differences are difficult to assess because sociocultural influences enter at an early point in childhood. If these claims of intrinsic differences are true, then gender differences in quantitative and mathematical abilities should emerge early in human development. We examined cross-sectional gender differences in mathematical cognition from over 500 children aged 6 months to 8 years by compiling data from five published studies with unpublished data from longitudinal records. We targeted three key milestones of numerical development: numerosity perception, culturally trained counting, and formal and informal elementary mathematics concepts. In addition to testing for statistical differences between boys’ and girls’ mean performance and variability, we also tested for statistical equivalence between boys’ and girls’ performance. Across all stages of numerical development, analyses consistently revealed that boys and girls do not differ in early quantitative and mathematical ability. These findings indicate that boys and girls are equally equipped to reason about mathematics during early childhood.

What makes a man attractive?

In many species female mate preference is influenced by signs indicating the health and robustness of the potential male partner. Rehm points to work by Versluys et al. examining the effects of male arm to body and intra-limb ratio on the preferences of heterosexual US women by showing them computer-generated male images that vary average body proportions from 9000 US military men by making arms and legs slightly longer or shorter. Previous research had shown that women prefer men with legs that are about half their height (legs that are too short have been linked to type 2 diabetes). How long the model’s arms were relative to his height didn’t seem to matter; and women cared only a little about how the elbow or knee divided a limb. But as seen in previous work, women noticed if the legs made up more or less than half his height—and they didn’t like it.

Computerized Gaydar - a threat to privacy and safety of gay people

My Oct. 13, 2017 post dealt with controversy over an article referenced as forthcoming that showed neural networks to be more accurate than humans at detecting sexual orientation. It has now appeared, and I want to pass on its abstract here:

We show that faces contain much more information about sexual orientation than can be perceived or interpreted by the human brain. We used deep neural networks to extract features from 35,326 facial images. These features were entered into a logistic regression aimed at classifying sexual orientation. Given a single facial image, a classifier could correctly distinguish between gay and heterosexual men in 81% of cases, and in 71% of cases for women. Human judges achieved much lower accuracy: 61% for men and 54% for women. The accuracy of the algorithm increased to 91% and 83%, respectively, given five facial images per person. Facial features employed by the classifier included both fixed (e.g., nose shape) and transient facial features (e.g., grooming style). Consistent with the prenatal hormone theory of sexual orientation, gay men and women tended to have gender-atypical facial morphology, expression, and grooming styles. Prediction models aimed at gender alone allowed for detecting gay males with 57% accuracy and gay females with 58% accuracy. Those findings advance our understanding of the origins of sexual orientation and the limits of human perception. Additionally, given that companies and governments are increasingly using computer vision algorithms to detect people’s intimate traits, our findings expose a threat to the privacy and safety of gay men and women. 

Explanation of fraternal birth order effect on sexual orientation.

A number of studies have by now confirmed that the probability of a boy growing up to be gay increases for each older brother born to the same mother, the so-called fraternal birth order (FBO) effect. Between 15% and 29% of gay men owe their sexual orientation to this effect. Bogaert et al. now present direct biochemical evidence indicating that the increased incidence of homosexuality in males with older brothers results from a progressive immunization of the mother against a male-specific cell-adhesion protein that plays a key role in cell–cell interactions, specifically in the process of synapse formation. Here are the details:

Significance

Gay men have, on average, a greater number of older brothers than do heterosexual men, a well-known finding within sexual science. This finding has been termed the fraternal birth order effect. Strong scientific interest in sexual orientation exists because it is a fundamental human characteristic, and because its origins are often the focal point of considerable social controversy. Our study is a major advance in understanding the origins of sexual orientation in men by providing support for a theorized but previously unexamined biological mechanism—a maternal immune response to a protein important in male fetal brain development—and by beginning to explain one of the most reliable correlates of male homosexuality: older brothers.

Abstract

We conducted a direct test of an immunological explanation of the finding that gay men have a greater number of older brothers than do heterosexual men. This explanation posits that some mothers develop antibodies against a Y-linked protein important in male brain development, and that this effect becomes increasingly likely with each male gestation, altering brain structures underlying sexual orientation in their later-born sons. Immune assays targeting two Y-linked proteins important in brain development—protocadherin 11 Y-linked (PCDH11Y) and neuroligin 4 Y-linked (NLGN4Y; isoforms 1 and 2)—were developed. Plasma from mothers of sons, about half of whom had a gay son, along with additional controls (women with no sons, men) was analyzed for male protein-specific antibodies. Results indicated women had significantly higher anti-NLGN4Y levels than men. In addition, after statistically controlling for number of pregnancies, mothers of gay sons, particularly those with older brothers, had significantly higher anti-NLGN4Y levels than did the control samples of women, including mothers of heterosexual sons. The results suggest an association between a maternal immune response to NLGN4Y and subsequent sexual orientation in male offspring.

Cognitive reflection in men impaired by single testosterone dose

An interesting bit from Nave et al.:

In nonhumans, the sex steroid testosterone regulates reproductive behaviors such as fighting between males and mating. In humans, correlational studies have linked testosterone with aggression and disorders associated with poor impulse control, but the neuropsychological processes at work are poorly understood. Building on a dual-process framework, we propose a mechanism underlying testosterone’s behavioral effects in humans: reduction in cognitive reflection. In the largest study of behavioral effects of testosterone administration to date, 243 men received either testosterone or placebo and took the Cognitive Reflection Test (CRT), which estimates the capacity to override incorrect intuitive judgments with deliberate correct responses. Testosterone administration reduced CRT scores. The effect remained after we controlled for age, mood, math skills, whether participants believed they had received the placebo or testosterone, and the effects of 14 additional hormones, and it held for each of the CRT questions in isolation. Our findings suggest a mechanism underlying testosterone’s diverse effects on humans’ judgments and decision making and provide novel, clear, and testable predictions.

A 'Gaydar' machine?

Heather Murphy describes the kerfuffle that has ensued after Stanford researchers published a preprint of their work that will soon appear in The Journal of Personality and Social Psychlogy. To teach a machine (a widely used facial analysis program employing a pattern identifying neural network) to detect sexuality, authors Kosinski and Wang copied more than 75,000 dating profiles of men and women seeking same or different sex partners. The software extracted information from thousands of facial data points to generate average composite heterosexual and gay male and female faces (pictures are in the Murphy article). They found that their model did much better than humans at identifying sexual orientation. When the computer was given five photos for each person instead of just one, accuracy rose to 83% for women and 91% for men.

The negative Tweet storms and blog posts criticized the study as being a technology-fueled revival of the long discredited notion that physiognomy, measuring the size and shape of a person's eyes, nose and face, can predict personality traits. Highly inaccurate science, racism by algorithm, etc.

And, even if the machine works as stated, William T.L. Cox, a psychologist who studies stereotypes at the University of Wisconsin-Madison, notes:

Let’s say 5 percent of the population is gay, or 50 of every 1,000 people. A facial scan that is 91 percent accurate would misidentify 9 percent of straight people as gay; in the example above, that’s 85 people (0.91 x 950).

The software would also mistake 9 percent of gay people as straight people. The result: Of 130 people the facial scan identified as gay, 85 actually would be straight.

When an algorithm with 91 percent accuracy operates in the real world, almost two-thirds of the times it says someone is gay, it would be wrong.

You want younger or older?

Interesting piece from Mona Chalabi:

(According to the Census Bureau, the average age difference between men and their wives is 2.3 years.)

Gender and the conflation of equality and sameness

I want to pass on some clips from a sane brief essay by Helena Cronin, author of "The Ant and the Peacock: Altruism and Sexual Selection from Darwin to Today."

The poet Philip Larkin famously proclaimed that sex began in 1963. He was inaccurate by 800 million years. Moreover, what began in the 1960s was instead a campaign to oust sex—in particular, sex differences—in favor of gender...biological differences were thought to spell genetic determinism, immutability, anti-feminism and, most egregiously, women's oppression. Gender, however, was the realm of societal forces; "male" and "female" were social constructs...

...gender has distorted social policy. This is because the campaign has undergone baleful mission-creep. Its aim has morphed from ending discrimination against women into a deeply misguided quest for sameness of outcome for males and females in all fields—above all, 50:50 across the entire workplace. This stems from a fundamental error: the conflation of equality and sameness. And it's an error all too easily made if your starting point is that the sexes are "really" the same and that apparent differences are mere artifacts of sexist socialization.

Equality is about fair treatment, not about people or outcomes being identical; so fairness does not and should not require sameness. However, when sameness gets confused with equality—and equality is of course to do with fairness—then sameness ends up undeservedly sharing their moral high ground. And male/female discrepancies become a moral crusade. Why so few women CEOs or engineers? It becomes socially suspect to explain this as the result not of discrimination but of differential choice.

Well, it shouldn’t be suspect. Because the sexes do differ—and in ways that, on average, make a notable difference to their distribution in today's workplace.

Here's why the sexes differ. A sexual organism must divide its total reproductive investment into two—competing for mates and caring for offspring. Almost from the dawn of sexual reproduction, one sex specialized slightly more in competing for mates and the other slightly more in caring for offspring...the differences go far beyond reproductive plumbing. They are distinctive adaptations for the different life-strategies of competers and carers. Wherever ancestral males and females faced different adaptive problems, we should expect sex differences—encompassing bodies, brains and behaviour. And we should expect that, reflecting those differences, competers and carers will have correspondingly different life-priorities.

As for different outcomes in the workplace, the causes are above all different interests and temperaments (and not women being "less clever" than men). Women on average have a strong preference for working with people—hence the nurses and teachers; and, compared to men, they care more about family and relationships and have broader interests and priorities—hence little appeal in becoming CEOs. Men have far more interest in "things"—hence the engineers; and they are vastly more competitive: more risk-taking, ambitious, status-seeking, single-minded, opportunistic—hence the CEOs. So men and women have, on average, different conceptions of what constitutes success (despite the gender quest to impose the same—male—conception on all).

And here's some intriguing evidence. "Gender" predicts that, as discrimination diminishes, males and females will increasingly converge. But a study of 55 nations found that it was in the most liberal, democratic, equality-driven countries that divergence was greatest. The less the sexism, the greater the sex differences. Difference, this suggests, is evidence not of oppression but of choice; not socialization, not patriarchy, not false consciousness, not even pink t-shirts or personal pronouns … but female choice.

An evolutionary understanding shows that you can't have sex without sex differences. It is only within that powerful scientific framework—in which ideological questions become empirical answers—that gender can be properly understood. And, as the fluidity of "sexualities" enters public awareness, sex is again crucial for informed, enlightened discussion.

So for the sake of science, society and sense, bring back sex.

Explaining gender differences in anxiety.

Li et al. find that a set of oxytocin-responsive neurons in the medial prefrontal cortex (mPFC) look similar in both sexes, but in males they secrete a protein (CRHBP) that antagonizes the effect of the corticotropin-releasing hormone (CRH) associated with stress, thus causing an anti-anxiety effect with males that is not seen in females. This suggests the possibility of developing gender specific therapies for anxiety.

Highlights

•Activation of OxtrINs (oxytocin receptor interneurons) is anxiolytic in males and prosocial in females 

•OxtrINs specifically express CRHBP, an inhibitor of the stress hormone CRH 

•CRHBP blocks activation of layer 2/3 pyramidal cells by CRH only in males 

•OxtrINs in the mPFC (medial prefrontal cortex) coordinate sexually dimorphic social/emotional behaviors

Summary

The frequency of human social and emotional disorders varies significantly between males and females. We have recently reported that oxytocin receptor interneurons (OxtrINs) modulate female sociosexual behavior. Here, we show that, in male mice, OxtrINs regulate anxiety-related behaviors. We demonstrate that corticotropin-releasing-hormone-binding protein (CRHBP), an antagonist of the stress hormone CRH, is specifically expressed in OxtrINs. Production of CRHBP blocks the CRH-induced potentiation of postsynaptic layer 2/3 pyramidal cell activity of male, but not female, mice, thus producing an anxiolytic effect. Our data identify OxtrINs as critical for modulation of social and emotional behaviors in both females and males and reveal a molecular mechanism that acts on local medial prefrontal cortex (mPFC) circuits to coordinate responses to OXT and CRH. They suggest that additional studies of the impact of the OXT/OXTR and CRHBP/CRH pathways in males and females will be important in development of gender-specific therapies.

Men are more friendly after conflict than women.

Interesting stuff from Benenson and Wrangham, whose findings suggest the deep evolutionary history of male bonding. Men affiliate more after one-on-one conflicts than women, which facilitates future intragroup cooperation.

Highlights

•After sports matches, male opponents engage in friendly touches longer than females •Male winners and losers make more friendly touches than their female counterparts

Summary

The nature of ancestral human social structure and the circumstances in which men or women tend to be more cooperative are subjects of intense debate. The male warrior hypothesis proposes that success in intergroup contests has been vital in human evolution and that men therefore must engage in maximally effective intragroup cooperation. Post-conflict affiliation between opponents is further proposed to facilitate future cooperation, which has been demonstrated in non-human primates and humans. The sex that invests more in post-conflict affiliation, therefore, should cooperate more. Supportive evidence comes from chimpanzees, a close genetic relative to humans that also engages in male intergroup aggression. Here we apply this principle to humans by testing the hypothesis that among members of a large community, following a conflict, males are predisposed to be more ready than females to repair their relationship via friendly contact. We took high-level sports matches as a proxy for intragroup conflict, because they occur within a large organization and constitute semi-naturalistic, standardized, aggressive, and intense confrontations. Duration or frequency of peaceful physical contacts served as the measure of post-conflict affiliation because they are strongly associated with pro-social intentions. Across tennis, table tennis, badminton, and boxing, with participants from 44 countries, duration of post-conflict affiliation was longer for males than females. Our results indicate that unrelated human males are more predisposed than females to invest in a behavior, post-conflict affiliation, that is expected to facilitate future intragroup cooperation.

Testosterone in men is associated with status enhancing behaviors.

Seeing this piece by Dreher et al. makes me wonder what Donald Trump's testosterone levels are....

Significance

Although in several species of bird and animal, testosterone increases male–male aggression, in human males, it has been suggested to instead promote both aggressive and nonaggressive behaviors that enhance social status. However, causal evidence distinguishing these accounts is lacking. Here, we tested between these hypotheses in men injected with testosterone or placebo in a double-blind, randomized design. Participants played a modified Ultimatum Game, which included the opportunity to punish or reward the other player. Administration of testosterone caused increased punishment of the other player but also, increased reward of larger offers. These findings show that testosterone can cause prosocial behavior in males and provide causal evidence for the social status hypothesis in men.

Abstract

Although popular discussion of testosterone’s influence on males often centers on aggression and antisocial behavior, contemporary theorists have proposed that it instead enhances behaviors involved in obtaining and maintaining a high social status. Two central distinguishing but untested predictions of this theory are that testosterone selectively increases status-relevant aggressive behaviors, such as responses to provocation, but that it also promotes nonaggressive behaviors, such as generosity toward others, when they are appropriate for increasing status. Here, we tested these hypotheses in healthy young males by injecting testosterone enanthate or a placebo in a double-blind, between-subjects, randomized design (n = 40). Participants played a version of the Ultimatum Game that was modified so that, having accepted or rejected an offer from the proposer, participants then had the opportunity to punish or reward the proposer at a proportionate cost to themselves. We found that participants treated with testosterone were more likely to punish the proposer and that higher testosterone levels were specifically associated with increased punishment of proposers who made unfair offers, indicating that testosterone indeed potentiates aggressive responses to provocation. Furthermore, when participants administered testosterone received large offers, they were more likely to reward the proposer and also chose rewards of greater magnitude. This increased generosity in the absence of provocation indicates that testosterone can also cause prosocial behaviors that are appropriate for increasing status. These findings are inconsistent with a simple relationship between testosterone and aggression and provide causal evidence for a more complex role for testosterone in driving status-enhancing behaviors in males.

Homosexuality as a discrete class.

Norris et al. contribute to previous work engaging the question of whether homosexuality has a taxonic structure of categories of individuals with distinct orientation, or whether sexual orientation lies on the sort of continuum suggested by Kinsey and others. Because individuals who report nonheterosexual identities, behavior, and attractions are more likely than heterosexual individuals to meet criteria for a psychiatric disorder their study utilized a National Epidemiologic Survey on Alcohol and Related Conditions. The survey was conducted through personal interviews with one randomly selected adult in each household. Their abstract:

Previous research on the latent structure of sexual orientation has returned conflicting results, with some studies finding a dimensional structure (i.e., ranging quantitatively along a spectrum) and others a taxonic structure (i.e., categories of individuals with distinct orientations). The current study used a sample (N = 33,525) from the National Epidemiologic Survey on Alcohol and Related Conditions (NESARC). A series of taxometric analyses were conducted using three indicators of sexual orientation: identity, behavior, and attraction. These analyses, performed separately for women and men, revealed low-base-rate same-sex-oriented taxa for men (base rate = 3.0% of those sampled) and women (base rate = 2.7%). Generally, taxon membership conferred an increased risk for psychiatric and substance-use disorders. Although taxa were present for men and women, women demonstrated greater sexual fluidity, such that any level of same-sex sexuality conferred taxon membership for men but not for women.

Male and female brains do not constitute two distinct categories.

From Zoel et al.: Significance

Sex/gender differences in the brain are of high social interest because their presence is typically assumed to prove that humans belong to two distinct categories not only in terms of their genitalia, and thus justify differential treatment of males and females. Here we show that, although there are sex/gender differences in brain and behavior, humans and human brains are comprised of unique “mosaics” of features, some more common in females compared with males, some more common in males compared with females, and some common in both females and males. Our results demonstrate that regardless of the cause of observed sex/gender differences in brain and behavior (nature or nurture), human brains cannot be categorized into two distinct classes: male brain/female brain.

Abstract

Whereas a categorical difference in the genitals has always been acknowledged, the question of how far these categories extend into human biology is still not resolved. Documented sex/gender differences in the brain are often taken as support of a sexually dimorphic view of human brains (“female brain” or “male brain”). However, such a distinction would be possible only if sex/gender differences in brain features were highly dimorphic (i.e., little overlap between the forms of these features in males and females) and internally consistent (i.e., a brain has only “male” or only “female” features). Here, analysis of MRIs of more than 1,400 human brains from four datasets reveals extensive overlap between the distributions of females and males for all gray matter, white matter, and connections assessed. Moreover, analyses of internal consistency reveal that brains with features that are consistently at one end of the “maleness-femaleness” continuum are rare. Rather, most brains are comprised of unique “mosaics” of features, some more common in females compared with males, some more common in males compared with females, and some common in both females and males. Our findings are robust across sample, age, type of MRI, and method of analysis. These findings are corroborated by a similar analysis of personality traits, attitudes, interests, and behaviors of more than 5,500 individuals, which reveals that internal consistency is extremely rare. Our study demonstrates that, although there are sex/gender differences in the brain, human brains do not belong to one of two distinct categories: male brain/female brain.