How often does Donald Trump wash his hands?

How clean is that finger, Donald?
How clean is that finger, Donald?

Move over Nate Silver! The statistician and author of The Signal and the Noise: Why So Many Predictions Fail – But Some Don’t may have called 49 out of 50 states right in the 2012 US Presidential election. But today I note that my predictions for the 2014 mid-term elections were 100 percent correct.

Mostly, that’s because I made only one. But it was a goodie. Noting the hysteria that then abounded about the West African Ebola outbreak, I predicted that it would propel a rightward swing in the mid-terms.

One might expect that an epidemic limited almost entirely to West Africa should be way, way down on the list of factors likely to swing American voters. What with ISIS, the economy, Obamacare, abortion and so many other issues of greater direct relevance to the United States.

But a spectacularly scary hemorrhagic fever outbreak – ravaging countries a mere single plane flight from the USA! – holds the potential to propel a rightward swing next Tuesday.

Readers of this column will know of my obsession with understanding how evolved psychological traits shape ideological and political differences. My Elections in the Time of Ebola column drew a link between heightened disgust sensitivity, outgroup fear and conservative voting intentions. Noting the U.S. media’s apparent terror of Ebola reaching American shores (rather than, say, visiting horrific hemorrhagic death on hundred, and displacing or inconveniencing hundreds of thousands of mostly poor Africans), I suggested that keeping Ebola fears foremost might flush out the right-wing vote.

Turns out that’s exactly what happened. Psychological Science just published a paper by Alec T. Beall, Marlie K. Hofer and Mark Schaller with the captivating title Infections and Elections: Did an Ebola Outbreak Influence the 2014 U.S. Federal Elections (and if so, How)?. Schaller was the first to propose the crucial, to that time unexpected, links between disease, disgust and political traits like outgroup fear and conservatism. And his group lead the world in studying not only the links but the psychological basis for those links.

Outbreak

The 2014 Ebola outbreak began in Guinea, and first gained international attention in March 2014. Six months later, the outbreak was ravaging West Africa, and flaring up in other parts of the world. On September 30 2014, The US Center for Disease Control confirmed that a man who had traveled to Dallas, Texas from Liberia had Ebola. He subsequently died, and two nurses who had treated him were infected but recovered. And on 23 October, Craig Spencer, a Medicins Sans Frontieres doctor who had cared for Ebola victims in Guinea became the fourth and last case in the US ‘outbreak’.

Once the CDC announced that Ebola had made it to the U.S.A., media coverage there intensified and people grew markedly more concerned about the possibility of an epidemic. Beall, Hofer and Schaller recognised the importance of this transition, and so they analysed polling trends from September and October, as well as the volume of Internet searches for the term “Ebola”.

Interestingly, after the first of October, once the possibility of an Ebola outbreak in the USA became more salient, voters’ intentions swung discernibly toward Republican candidates. And the more voters searched for “Ebola”, the stronger the change in their voting intentions.

Interestingly, people’s concerns about Ebola appear to have influenced voting intentions in states that traditionally favour Republican candidates, but not in those that predictably vote Democrat. One might expect conservative politicians to play up disease fears particularly strongly within conservative electorates that appear to be flirting with swinging left.

Politicians should have clean hands
Politicians should have clean hands

The Hands of The Donald

Fortunately for West Africa, and for progressive politicians in general, the Ebola outbreak is largely over. That won’t stop politicians from appealing to voters’ basest fears. Donald Trump has done so shamelessly in his claims that Mexican immigrants bring “tremendous infectious disease … pouring across the border”.

From Vanity Fair editor Graydon Carter’s repeated characterisation of Trump as a “short-fingered vulgarian” to Marco Rubio’s desperate attempts to imply a Trumpish deficiency in the penis department, Trump’s hands get a lot of attention. So much so that he recently saw fit to defend his own hands
in an interview with the The Washington Post’s editorial board:

“Normal,” the Republican presidential front-runner insisted. “Strong.” “Good size.” “Great.” “Fine.” “Slightly large, actually.”

Perhaps it isn’t the size of his hands that matters in this election. Perhaps we should be paying attention to how clean he can keep them?

AC/DC “Dirty Deeds (Done Dirt Cheap)” Live at the River Plate.The Conversation

This article was originally published on The Conversation. Read the original article.

Life’s short, have you had an affair?

Today, millions of very nervous adults are furtively checking sites like “Have I been Pwned” to check if their account details at Ashley Madison have been leaked. Others are checking if their partners or acquaintances had accounts. The hacking and subsequent release of data from the world’s biggest infidelity-focussed dating service continues to reverberate, provoking an interesting suite of ethical questions.

Unless you’ve confined your news intake to re-runs of Jarryd Hayne’s BIG MOMENT in a trial game for the 49ers, you will be well aware that a group calling themselves Impact Team hacked the systems of Avid Life Media (ALM), who operate a number of sex and dating websites. Impact Team threatened to release sensitive information about users unless ALM close down Ashley Madison, which specialises in connecting people looking to have extra-relationship affairs, and Established Men, which they argue is a “website for rich men to pay for sex”. Established Men, understandably, puts it a little more gently: “connecting young, beautiful women with interesting men”.

Shhhhh! Ashley Madison screenshot.
Shhhhh! Ashley Madison screenshot.

So much for the libertarian hacker stereotype. Impact Team are waging a moralist crusade against both the websites themselves, and the people whose extra-marital or transactional sex shennanigans the websites enable.

Neither website has been shut down and yesterday Impact Team uploaded information about over 30 million users, including their email addresses. Security experts quoted in news outlets seem to agree that the data dump is genuine.

The media coverage has varied from titillating attempts to dissect where the “cheating” hotspots are to the very real personal stories of spouses who’ve been busted. Sydney radio station NOVA even tried, and rather spectacularly failed, to turn it into edgy commercial radio, searching the database on behalf of callers. They very quickly learned how spectacularly bad their idea was when they found the husband of one of their callers was indeed subscribed to Ashley Madison.

Nobody wins here. The whole business reeks of weakness and failure. As Gaby Hinsliff put it in the Guardian,

it’s hard to decide which of the activities involved – cyber blackmail, building a business on wrecking marriages, or just good old-fashioned philandering – is least charming.

More than gossip

But some people seem bouyed by the whole business. I’m intrigued by the level of schadenfreude; so many people are relishing the slow implosion of Ashley Madison and the exposure of millions of people’s most embarrassing intimate details. What disappoints me most is how the exposure of 30 million people is being shoe-horned into a one-size-fits-all view of sex and relationships. How this is all about “cheating”, and that infidelity means the same thing in every relationship.

We might not like to admit it to ourselves, but relationships differ enormously from one another. So do the reasons people have sex, both within and outside of committed relationships. Yes, a great many – probably most – Ashley Madison clients were furtively seeking extra sexual partners without the knowledge and consent of their long-term partners. And many did so despite their relationships being otherwise functional, productive and respectful. This kind of infidelity has its victims: the partners who remain at home, pouring their selves into the shared enterprise of coupledom, unaware that the other party isn’t matching their effort and commitment.

According to Leonard Cohen (Live in London), “Everybody Knows that you’ve been faithful. Give or take a night or two”.

And yet nobody can properly evaluate another’s relationship from outside, much less 30 million relationships. The evolutionary sciences continue to show that humans have a marvellous capacity to form loving, cooperative relationships, to remain sexually faithful to one another, and to work hard to build both families and wealth. Marvellous as those relationships can be, profound as the love that binds us together might feel, not all relationships remain functional.

One of the less-explored dimensions of the Ashley Madison schamozzle is the fact that many people had quite defensible positions for looking outside their relationships. Their current relationships might be loveless, sexless, dysfunctional, exploitative or even abusive. They may be in the process of coming out to themselves, facing the daily dissonance of being gay in a straight marriage.

A great many people are trapped by economic circumstances and questions of child custody in hellish relationships. Who would deny those people the chance to connect with another, perhaps to find the courage or even the ally they need to escape, or perhaps to enjoy being loved, appreciated and getting properly laid?

How many people, whose names appeared on that database last night, had to go home to their controlling, jealous, or abusive partners? How many people, living straight lives, many in countries where homosexuality is illegal and harshly punished, were outed by Impact Team’s self-righteous moralism?

Beyond the many dysfunctional relationships from which affairs might offer respite or escape, the Ashley Madison affair forces us to confront even more uncomfortable realities about relationships. Even “a mommy and daddy who love each other very much” are likely to find that they cannot be everything one another needs. Our evolved capacity to be really quite good at monogamy has its limits. We have also evolved, thanks to our ancestors’ tastes for sexual intrigue, an exquisitely context-dependent capacity to throw off the shackles of monogamy when it suits us. It takes a spectacular denial of human nature to believe that life-long heterosexual monogamy represents some kind of social zenith and that deviations from this one true path represent deep aberrations.

On-line dating has imposed what economists call a “technological shock” on the mating market, reshaping how people meet, court and, ultimately, mate. Ashley Madison’s success, and the marketing genius behind it’s quasi-inspirational slogan (“Life’s short. Have an affair.”), reshaped the extra-couple mating market. And the realisation to which so many customers are waking today, that even a website set up to guarantee discretion in extracurricular hooking up is vulnerable to hacking and public shaming, will change the dynamics of sex once again.

I would be disappointed if the whole business turns into a witchhunt on “cheaters”, if we slide back toward the puritanism that had Hester Prynne wearing the Scarlet Letter. Perhaps we need to embrace the messier, more complex reality that sex does not equal love, and love does not always mean exclusively and forever. Our relationships are negotiated every day in the way we treat one another and accept our partners, and lovers, as they are, rather than packing them into the neat box of a one-size-fits-all relationship.

The Conversation

Rob Brooks is Scientia Professor of Evolutionary Ecology; Director, Evolution & Ecology Research Centre at UNSW Australia

This article was originally published on The Conversation. Read the original article.

Early bird gets the sperm … to the egg

What gets you out of bed in the morning? Before morning has broken, and some time before blackbird has spoken, songbirds rise for sex. And a clever new experiment reveals just how important it is for male songbirds not to sleep in.

A great many species of songbirds nest in pairs, presenting to the world a facade of monogamy. Until the 1990’s, songbirds were rhapsodised by social conservatives as paragons of family values, mother and father working together faithfully to fledge their demanding chicks. Until new genetic technologies revealed that most socially monogamous birds were playing a lot of away games.

For a long time, ornithologists failed to spot the shennaniganising because most of it happens just before dawn, when even the hardiest birdo is still rubbing sleep from their eyes. That’s actually a bit unfair: ANU’s Professor Andrew Cockburn and his many collaborators have risen unspeakably early for decades to study Australia’s superb fairy wrens, revealing them to be Olympic medallists of extra-pair sex. Female wrens leave the nest before dawn, heading straight to males singing in the dawn chorus.

This kind of behaviour gives male birds two reasons to rise early: to prevent their social mate from mating with another male, and perhaps to get a little bit on the side from some other male’s social mate. European blue tit males who start singing early in the morning sire more chicks with other females, chicks he doesn’t have to raise because the female and her social mate do all the heavy lifting.

No wonder those Three Little Birds were cheerful when Bob Marley rose and smiled with the rising sun!

Consequences

But how do early and late risers do with their social mates? A team based at the Max Planck Institute for Ornithology in Radolfzell, Germany, found an ingenious way to answer this question.

By inserting slow-release melatonin implants beneath the skin of free-living male Great Tits, just before the breeding season, they tweaked the birds’ circadian rhythms. The body releases the hormone melatonin at night, and animal circadian activity patterns are cued by melatonin levels. Nocturnal animals are stirred into activity and dirurnal animals to sleep by rising melatonin.

Early rising male Great Tits can get the sexy stuff over with and spend the res of the day looking fabulous. Israel Gutiérrez/flickr
Early rising male Great Tits can get the sexy stuff over with and spend the res of the day looking fabulous. Israel Gutiérrez/flickr

Male great tits in the control group became active about 22 minutes before dawn, but those with melatonin implants took an extra ten minutes to get going. They were no less active during the day, and they stopped for the night at the same time, a few minutes before dusk.

But those extra ten minutes cost the males dearly. Twelve percent of chicks fledged from the nests of control males were sired by another male, but 42 percent of chicks in the nests of melatonin-implanted males had been conceived with another male’s sperm.

As an early riser, I’d like to claim victory for the early birds at this point. But of course I can’t. For humans, Sex at Dawn remains niche. Many even prefer to rise early for bird watching.

The night time is where the action is for our species. Night owls tend to be more extrovert, novelty-seeking, and night-owl men (but not women) report having more sexual partners. Night-owls are more likely than early risers to be single and open to short-term commitment-free sex. Being a night owl is associated with risk-taking in women on a levels similar to males (both night-owls and early risers). Risk-taking predicts short-term sexual behaviour, suggesting that female night owls might be especially oriented toward sex.

Interesting, it’s true, but not yet the basis for any firm prescriptions. Unless you’re Charlotte Alter writing at Time Magazine. Anybody spot the implicit bias and rampant earlybirdophobia?

Women who stay up late are more likely to get laid, but less likely to get married than women who get up early to do a sun salutation or whatever.

Whatever indeed!

Up all night to get lucky? Thank you Daft Punk!

The Conversation

Rob Brooks is Scientia Professor of Evolutionary Ecology; Director, Evolution & Ecology Research Centre at UNSW Australia

This article was originally published on The Conversation. Read the original article.

Is there really a single ideal body shape for women?

Boticelli's "Birth of Venus" c. 1486.
Boticelli’s “Birth of Venus” c. 1486.

Many scholars of Renaissance art tell us that Botticelli’s Birth of Venus captures the tension between the celestial perfection of divine beauty and its flawed earthly manifestation. As classical ideas blossomed anew in 15th-century Florence, Botticelli could not have missed the popular Neoplatonic notion that contemplating earthly beauty teaches us about the divine.

Evolutionary biologists aren’t all that Neoplatonic. Like most scientists, we’ve long stopped contemplating the celestial, having – to appropriate Laplace’s immortal words to Napoleon – “no need of that hypothesis”. It is the messy imperfection of the real world that interests us on its own terms.

My own speciality concerns the messy conflicts that inhere to love, sex and beauty. Attempts to cultivate a simple understanding of beauty – one that can fill a 200-word magazine ad promoting age-reversing snake oil, for example – tend to consistently come up short.

Waist to hip

Nowhere does the barren distinction between biology and culture grow more physically obvious than in the discussion of women’s body shapes and attractiveness. The biological study of body shape has, for two decades, been preoccupied with the ratio of waist to hip circumference.

With clever experimental manipulations of line drawings, Devendra Singh famously demonstrated that images of women with waists 70% as big as their hips tend to be most attractive. This 0.7:1 waist-to-hip ratio (WHR), it turns out, also reflects a distribution of abdominal fat associated with good health and fertility.

Singh also showed that Miss America pageant winners and Playboy playmates tended to have a WHR of 0.7 despite changes in the general slenderness of these two samples of women thought to embody American beauty ideals.

Singh’s experiments were repeated in a variety of countries and societies that differ in both average body shape and apparent ideals. The results weren’t unanimous, but a waist-to-hip ratio of 0.7 came up as most attractive more often than not. The idea of an optimal ratio is so appealing in its simplicity that it became a staple factoid for magazines such as Cosmo.

There’s plenty to argue about with waist-hip ratio research. Some researchers have found that other indices, like Body Mass Index (BMI) explain body attractiveness more effectively.

But others reject the reductionism of measures like WHR and BMI altogether. This rejection reaches its extremes in the notion that ideas of body attractiveness are entirely culturally constructed and arbitrary. Or, more sinisterly, designed by our capitalist overlords in the diet industry to be inherently unattainable.

The evidence? The observation that women’s bodies differ, on average, between places or times. That’s the idea animating the following video, long on production values, short on scholarship and truly astronomic on the number of hits (21 million-plus at the time of writing):

This rather questionable video, called ‘Women’s Ideal Body Types Throughout History’, is getting a lot of airplay on YouTube.

I note that Botticelli’s Venus looks more at home in the 20th Century than among the more full-figured Renaissance “ideals”. So do the Goddesses and Graces in La Primavera. Perhaps there was room for more than one kind of attractive body in the Florentine Renaissance? Or is the relationship between attractiveness and body shape less changeable and more variegated than videos like the one above would have us believe?

Not that I’m down on body shape diversity. Despite the fact that there seems to be only one way to make a supermodel, real women differ dramatically and quite different body types can be equally attractive. The science of attractiveness must grapple with variation, both within societies and among cultures.

Enter the BodyLab

For some years our research group has wrestled with exactly these issues, and with the fact that bodies vary in so many more dimensions than just their waists and their hips. To that end, we established the BodyLab project, a “digital ecosystem” in which people from all over the internet rate the attractiveness of curious-looking bodies like the male example below.

Example image from the BodyLab ‘digital ecosystem’. The VW Beetle is provided as the universal symbol of something-slightly-shorter-than-an-adult-human. Faces pixellated to preserve any grey people’s anonymity. Rob Brooks/BodyLab.biz
Example image from the BodyLab ‘digital ecosystem’. The VW Beetle is provided as the universal symbol of something-slightly-shorter-than-an-adult-human. Faces pixellated to preserve any grey people’s anonymity.
Rob Brooks/BodyLab.biz

We call it a “digital ecosystem” not to maximise pretentiousness, but because this experiment involved multiple generations of selection and evolution. We started with measurements of 20 American women, a sample representing a wide variety of body shapes.

We then “mutated” those measures, adding or subtracting small amounts of random variation to each of 24 traits. Taking these newly mutated measures we built digital bodies, giving them an attractive middle-grey skin tone in an attempt to keep variation in skin colour, texture etc out of the already complex story.

If you want to help out with our second study, on male bodies, visit BodyLab and click through to Body Shape Study and then Rate Males (Generation 6).

This all involved considerable technologic innovation, resulting in an experiment unlike any other. We had a population of bodies (120 per generation) that we could select after a few thousand people had rated them for attractiveness. We then “bred” from the most attractive half of all models and released the new generation into the digital ecosystem.

What did we find? In a paper just published at Evolution & Human Behavior, the most dramatic result was that the average model became more slender with each generation. Almost every measure of girth decreased dramatically, whereas legs and arms evolved to be longer.

In eight generations, the average body became more slender. Waist, seat, collar, bust, underbust, forearm, bicep, calf and thigh girth all decreased by more than one standard deviation. At the same time, leg length (inseam) rose by 1.4 standard deviations. Rob Brooks
In eight generations, the average body became more slender. Waist, seat, collar, bust, underbust, forearm, bicep, calf and thigh girth all decreased by more than one standard deviation. At the same time, leg length (inseam) rose by 1.4 standard deviations.
Rob Brooks

That may not seem surprising, particularly because the families “bred” from the most overweight individuals at the start of the experiment were eliminated in the first few generations.

But, after that, more families remained in the digital ecosystem, surviving generation after generation of selection, than we would have expected if there was a single most attractive body type. The Darwinian process we imposed on our bodies had started acting on the mutations we added during the breeding process.

More meaningful than the mean

Those “mutations” that we introduced allowed bodies to evolve free from all the developmental constraints that apply to real-world bodies. For example, leg lengths could evolve independently of arm lengths. Waists could get smaller even as thighs got bigger.

When we examined those five families that lasted longest as our digital ecosystem evolved, we observed a couple of interesting nuances.

First, selection targeted waist size itself, rather than waist-hip ratio. No statistical model involving hip size (either on its own or in waist-hip ratio) could come close to explaining attractiveness as well as waist size alone. Our subjects liked the look of slender models with especially slender waists. There was nothing magical about a 0.7 waist-to-hip ratio.

Second, within attractive families, which were the more slender families to begin with, evolution bucked the population-wide trend. These bodies began evolving to be more shapely, with bigger busts and more substantial curves.

It turns out there’s more than one way to make an attractive body, and those different body types evolve to be well-integrated. That’s a liberating message for most of us: evolutionary biology has more to offer our understanding of diversity than the idea that only one “most attractive” body (or face, or personality) always wins out.

What about the cultural constructionists? Are body ideals arbitrary, or tools of the patriarchal-commercial complex?

Our results suggest that the similarities between places, and even between male and female raters, are pretty strong: the 60,000 or so people who viewed and rated our images held broadly similar ideas of what was hot and what was not. But their tastes weren’t uniform. We think most individuals could see beauty in variety, if not in the full scope of diversity on offer.

What’s cool about our evolving bodies, however, is that we can run the experiment again and again. We can do so with different groups of subjects, or even using the same subjects before and after they’ve experienced some kind of intervention (perhaps body-image consciousness-raising?). I’m hoping we can use them to look, in unprecedented depth, at the intricate ways in which experience, culture and biology interact.

The Conversation

This article was originally published on The Conversation.
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Can science finger a philanderer? Not like this!

Two left hands make a heart. Source: Leon Brocard/Flickr
Two left hands make a heart. Source: Leon Brocard/Flickr

Are people naturally monogamous, polygamous or promiscuous? It’s one of those questions that most people feel quite confident in answering. Ask a few people and you’re likely to come up with a variety of contradictory answers, each delivered with considerable confidence. But the question is far more slippery than it first appears.

I will return later to the question of humanity’s “natural” mating system, but lately I’ve been far more interested in why people hold such strong opinions on the subject. And I think it’s mostly out of keenness to understand ourselves and those we love, to navigate the perilous tension between monogamy and non-monogamy that runs through our own lives. And, often, to validate our own proclivities.

With the Hallmark Holiday of St Valentine’s Day just a few days away, a recent study that touches on the monogamy-promiscuity tension deserves close examination. Particularly because various media outlets made it sound like a litmus test of whether someone is a likely ‘strayer’ or a certain ‘stayer’.

Sociosexuality

In ‘Stay or Stray: evidence for alternative mating strategy phenotypes in both men and women’, Rafael Wodarski, John Manning and Robin Dunbar probe the statistical distributions of two traits related to sexual behaviour. They ask whether sociosexuality and the relative lengths of the second and forth fingers (2D:4D ratio) conform to distributions with one peak or two. A bimodal distribution, with two peaks, suggests there may be two different groups of individuals within a given sample.

An individual’s sociosexuality reflects how restricted their attitudes toward sex and their sexual behaviours are. Wlodarski’s team used answers from the following six questions in the 9-item Revised Sociosexual Orientation Inventory (SOI):

  1. With how many different partners have you had sex within the past 12 months?
  2. With how many different partners have you had sexual intercourse on one and only one occasion?
  3. With how many different partners have you had sexual intercourse without having an interest in a long-term committed relationship with this person?
  4. Sex without love is OK. (this and the next two questions answered on a scale from strongly disagree to strongly agree)
  5. I can imagine myself being comfortable and enjoying “casual” sex with different partners.
  6. I do not want to have sex with a person until I am sure that we will have a long-term, serious relationship.

High scores (plenty of agreeing, and lots of casual sex) characterise an unrestricted sociosexuality, whereas people with restricted sociosexuality tend to get low scores.

The statistical tests showed that within fairly large samples of British and American subjects, there was evidence that both women’s and men’s SOI scores are distributed bimodally. But there’s plenty of overlap between the peaks (modes). The authors infer that within each sex exists a more restricted, monogamous group of individuals and another group of unrestricted promiscuous people.

Here, and in almost every study using SOI, men tend to have more unrestricted sociosexuality than women, on average. The difference in means could be pinned on small differences in the percentages of men and women in the restricted and unrestricted SOI groups.

Digit Ratios

The group also analysed a sample of hand measurements of 1314 British subjects. They looked at the ratio of the index finger (second digit, or 2D) to the ring finger (4D). Adults who were exposed to higher levels of testosterone when they were in the womb, tend to have relatively short index fingers (small 2D:4D ratio).

Hand with index finger shorter than the ring finger, resulting in a small 2D:4D ratio, pointing to a high exposure to testosterone in the uterus. source: Wikimedia Commons
Hand with index finger shorter than the ring finger, resulting in a small 2D:4D ratio, pointing to a high exposure to testosterone in the uterus. source: Wikimedia Commons

Now that you’ve stopped looking at your fingers, can we move along?

Prenatal testosterone exposure is also thought to bias individuals toward more promiscuous sexuality when they reach adulthood. The pattern also works across species: monkey and ape species with long-term pair bonds and a knack for monogamy tend to have high 2D:4D ratios.

Interestingly, when Wlodarski’s team applied their statistical tests to the distribution of 2D:4D ratios, they again found evidence of bimodality. A similar pattern in two very different traits associated with promiscuity-monogamy suggested to them a provocative conclusion:

Perhaps we are dealing here with two different types of people.

What if some folks are good at monogamy whereas others are rather better at … the other stuff? Perhaps. Funny thing about sex research is that any conclusion you arrive at will leave some people feeling validated and an almost equal number something more like violated.

We go on foot from here

But the idea is worth exploring. The valuable thing about this study is that it challenges our too-common tendency to see every trait as a continuum, with a few individuals at either end and the majority somewhere in the middle.

Interestingly, the two measures, SOI and 2D:4D ratio were from different samples. At no point did the researchers provide any evidence that the two groups separated on digit ratio were the same individuals as those separated on SOI. They couldn’t be: they were different samples.

The links between SOI and 2D:4D ratios are, at best, equivocal. Some studies find that low 2D:4D is associated with higher SOI. Other studies fail to find such effects. And a study of women and men from Brazil and from the Czech Republic, found that in both sexes a more feminine (higher) 2D:4D ratio is associated with less restricted sociosexuality.

But you wouldn’t know it from the media coverage. The Daily Mirror over-promised, trumpeting that “Boffins” have learned “How to work out if your partner is cheating on you? Check their fingers.” Well, checking if they’ve been hiding their wedding ring might tell you something, but checking out their 2D:4D ratio won’t help at all. Nonetheless, Valentine’s Day dinners are going to involve a lot of quizzical staring at fingers this year. (And not out of daydreaming that he might just put a ring on it.)

The Telegraph took a more introspective line under the headline “Are you promiscuous or faithful? Measure your index finger to find out.” Actually, a better way to figure out if you are promiscuous or faithful, or if you are likely to be in the future, is to ask yourself the questions in the Sociosexual Inventory. It’s pretty straightforward: if you’ve had plenty of one-off sex and lots of partners in the last year, then odds are that you bend toward promiscuity. At least at this point in your life. But I can imagine folks on both side of the 2D:4D distribution reassuring themselves that they are doing the right thing.

Sometimes I wonder why scientists even bother talking to the media. The public love to learn the latest things that “boffins have figured out”, but they deserve journalism that makes at least a token effort to grapple with the research or speak to said boffins.

What are we?

The distribution of SOI and 2D:4D cannot tell us all that much about humanity as a whole, other than that both women and men vary in their openness to casual sex and their proportional finger length.

But this variation is part of what makes human sexual behaviour so fascinating. Some people do seem at ease with life-long monogamy whereas others are shockingly bad at it.

How that variation arises presents a very interesting bevy of questions. Cue the usual intellectually bereft wrangling over nature and nurture as though the two were alternatives.

I’m sure there is more than one reason, but an obvious candidate for variation in sociosexuality is religion. Perhaps those who buy in to religious practices are more likely to be on the “restricted” end of the sociosexuality distribution, whereas those who have rejected or never embraced religion are more likely to be in the “unrestricted” peak?

For now, my preferred answer to the question “Are people naturally monogamous, polygamous or promiscuous?” is “YES”.

We have evolved adaptations that make some of us rather good at monogamy, some of the time. Until we’re not. We also have an evolved capacity to leave one partner for another, or to partner up with more than one person at a time, depending on our circumstances.

If you’re looking for natural history to vindicate your own particular preferred way of life over the alternatives, then you’re always going to be disappointed.

Monogamy can be complicated too. The Police knew this. Check out “Wrapped Around Your Finger

The Conversation

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Sexually despotic men rewrite history

Alfred L. Kroeber (left) with Ishi, the last member of California’s Yahi people, in 1911. Wikimedia Commons
Alfred L. Kroeber (left) with Ishi, the last member of California’s Yahi people, in 1911. Wikimedia Commons

“Heredity”, opined the pioneering cultural anthropologist Alfred L. Kroeber in 1915, “cannot be allowed to have acted any part in history”. I have yet to encounter a crisper expression of the view that biological explanations have no place in the study of society and history. Kroeber’s words have resonated through the social sciences for a century, divorcing nurture from nature, social from biological, at considerable harm to our understanding of society and what it means to be human.

 

Fortunately, many 21st Century anthropologists, economists, neuroscientists, geneticists, sociologists and thinkers so busily inter-disciplinary that they defy dusty departmental labels, are consigning the hoary distinction between nature and nurture to the past. Likewise the distinction between heredity and history is steadily dissolving as the where intimate links between evolutionary fitness and major historic transitions come into view.

Last week’s European Journal of Human Genetics, for example, carried a fascinating article led by evolutionary geneticist Patricia Balaresque exploring the signature of historic population expansions in the distribution of Y-chromosome genotypes of men alive today.

The Y of who, what and when

The the human Y chromosome represents a tiny portion of the genome, including the genes that trigger a foetus to develop into a male, rather than following the default female pathway. Every now and then a small change occurs in one of the less important parts of a Y-chromosome’s DNA. Such a change is passed to a man’s sons, those sons’ sons, and so on. That means there’s quite a bit of variation in these Y-chromosome sequences in any human population.

Marco Polo at the Kublai Khan. Miniature from the Travels of Marco Polo c 1298.
Marco Polo at the Kublai Khan. Miniature from the Travels of Marco Polo c 1298.

So if a man happens to have many sons, who each go on to have many sons and so on, one might detect a sudden surge in the frequency of the Y-chromosome sequence borne by that line of men (patriline). In 2003, a large team from Oxford University detected evidence of just such an event. Across much of Asia, one particular Y-chromosome sequence was carried by 8 percent of all men. In a paper pithily titled “The Genetic Legacy of the Mongols”, they famously fingered Genghis Khan as the chief suspect.

The pattern of variation within the lineage suggested that it originated in Mongolia approximately 1,000 years ago. Such a rapid spread cannot have occurred by chance; it must have been a result of selection. The lineage is carried by likely male-line descendants of Genghis Khan, and we therefore propose that it has spread by a novel form of social selection resulting from their behavior.

Where by ‘behaviour’ they mean more than the Great Khan’s triumph in unifying the Mongols and establishing the largest continuous empire history has ever known. For Khan was as much about the establishment of a genetic dynasty as a political one. According to one disputed quote, he once said:

The greatest joy for a man is to defeat his enemies, to drive them before him, to take from them all they possess, to see those they love in tears, to ride their horses, and to hold their wives and daughters in his arms.

Or words to that effect.

Such a genetic legacy is far more than the work of a single man. It is likely that Khan’s uncles, brothers and cousins, played a substantial role, too. And his direct male descendants spread both his empire and his genetic legacy. Ghenghis’ grandson, Kublai Khan, married four main Empresses, but, according to Marco Polo’s Travels was attended to by hundreds of beautiful young women, working five at a time in three-day shifts. And a much greater number of women, recruited to the palace but, after a second round of screening, not deemed perfect enough for the Khan himself, were bestowed on Kublai’s nobles, many of whom would have been relatives sharing his patriline and Y-chromosome.

Khan not the only one

The Mongol expansion is far from the only such event to leave a genetic signature. A 2005 paper identified a particularly successful lineage that expanded about 500 years ago in Northeastern China, possibly through the lineage who established the Quing Dynasty.

Last week’s findings report on a survey of 5321 men from 127 Asian populations, testing for evidence of similar population expansions. Belaresque and her collaborators identified eleven such events, including the ones tied to the expansions of the Mongols and the Qing dynasty. And some of those events date back as far as 2100 BCE.

The earliest expansions, between 2100 and 300 BCE, are associated with the flourishing of agriculture in the Fertile Crescent, East India, and South East Asia. As agriculture took hold, elites accumulated wealth and influence beyond anything our hunter-gatherer ancestors could have conceived. These represent perfect conditions for sexual despots: male rulers who take many wives, keep numerous concubines or mistresses, and have many offspring. They also establish successions that favour their male descendants, handing them the wealth and power to become sexual despots themselves.

Another expansion began around 1100 CE in the Near East and expanded to the South East Indian coast. This might be a signature of the “rapid expansion of Muslim power … after the establishment of a unified polity in the Arabian peninsula by Muhammad in the 7th Century and under the subsequent Caliphates”.

The Mongol and Qing expansions, and another from Northeast China beginning no earlier than 850 CE, were not associated with the establishment and spread of agriculture, but rather with nomadic, pastoral lifestyles made possible by the domestication of horses. Pastoral nomads ruled the steppes for thousands of years, thanks to their horse-powered mobility and fighting ability.

They established several empires, giving rise to hierarchies, elites and patrilineal reproductive despots like the Khans and the Qing. And their Silk Road trade corridor facilitated westward expansion of their genetic dynasties.

Heredity and History

Even in the rather well-studied case of Genghis Khan we are well beyond certain idenfification of the individual progenitors whose success sparked each expansion. Innovative analyses and lucky ancient DNA finds may yet do so for some cases. But the ability to detect great tides of patrilineal descent in societies of various types offers far more interesting possibilities than compelling personal narrative.

The evidence shows that with great power and wealth can come great evolutionary fitness. The tools are now falling into place to assess how much the psychological adaptations that shape reproductive success have given history its shape.

This is one tale where History certainly represents HIS Story. The fact that new Y chromosome sequences can spread so fast and so wide when history’s tide turns suggests that a very small number of sexually despotic men can leave massive numbers of descendants. But each man who traces his descent back to Genghis Khan or another such super-ancestor through an unbroken male line has sisters who do so too, save for the very last branch in their family tree. If 2% of people in Asia descend on a male-only lineage from the same male ancestor as Khan, then how many times do they descend from him through at least one female ancesor?

Each of us descends many times over from a great many sexual despots. It would be Kroeber-like wilful ignorance to be think we don’t also inherit many of the genes that biased their behaviour toward the accumulation of power, the vanquishing of rivals and reproductive despotism.

And when I say “we”, I don’t only mean men. Every man has a mother. Every descendant of Ghenghis Khan is also a descendant of his mother Hoelun.

The Conversation

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Economic dependence promotes prudishness

Stay home, bake whitebread, don't sleep around.
Stay home, bake whitebread, don’t sleep around.

Marriage, according to those who habitually preface the word with “traditional”, is a collaboration. With complementary roles, filled as predictably by one woman and one man as peanut butter fills the gap between two slices of white bread.

If you encounter somebody clinging to this view of marriage in which women happily traipse down the church aisle into economic dependence on their menfolk, then I’m sure you can predict their views on sex and the thousand other issues that inhere to sex:

Sex education? Abstain until marriage, ‘cos true love waits.

The pill? Okay if you’re using it to control your acne.

Abortion? Causes all those calamities the greenies like to pin on climate change.

Okay, my clumsy stereotype grows unkind. My point is that more often than not women’s economic dependence on men is bundled up with strong views against sexual promiscuity.

But why? Are economic dependence and anti-promiscuity morality both symptoms of the same cause? Patriarchy, perhaps? Or does one bring about the other? A new study in Archives of Sexual Behaviour suggests that economic dependence might lead to anti-promiscuity views.

Paternity no laughing matter

Visiting friends or relatives in the neonatal ward isn’t the place to crack jokes about paternity. In fact, most people, especially relatives of the new mum, go to great efforts to comment on the newborn’s likeness to the guy who thinks he’s dad.

Paternity stikes such a raw nerve with men because they can never be truly sure that they’re the father. At least they couldn’t until recent technological developments in DNA analysis made it possible.

And yet throughout our evolutionary past, some men thought they were working hard to raise their own genetic progeny where they were actually rearing the young of another. Men who were suspicious, jealous and not prepared to raise another man’s children might not have won any nice-guy prizes, but they did ensure their hard work contributed to the success of their own genes. Including any genes that disposed them to jealousy and vigilance about paternity. Unfortunately, we are all descended from many such men.

Today, humanity’s long history of insecurity over paternity can be seen in the politics of paternity testing and the undignified squabble over how many children are really sired by someone other than dad.

Sensitivities over paternity have shaped religious practices, laws, customs for the inheritance of wealth, and behavioural norms.

In their pop bestseller Sex at Dawn, Christopher Ryan and Cacilda Jethá argued that sexual jealousy and paternity insecurity are newcomers to human society, almost unknown in our species’ long hunting and gathering past where love flowed more freely and couples stayed together only briefly. The economic changes wrought by farming tied families to the land, necessitating cultural innovations to ensure wealth and land stayed within the family.

Ryan and Jethá make several mistakes, including unduly romanticising our hunter-gatherer ancestors, and viewing culture as something separate from biology. The cultural practices that surround fidelity and conception are more usefully viewed as extensions of men’s evolved paternity insecurity. And the scale of those extensions varies among places and over time.

When to worry about promiscuity

When women depend economically on their husbands or partners, then both women and men should value paternity certainty more highly. Men working hard to raise a family have plenty to lose in evolutionary terms if the children they raise are actually sired by somebody else. When men don’t do much for their partners or the offspring, they should be much more chilled about paternity, and thus much more relaxed about sexual promiscuity.

Likewise, when a woman depends heavily on a man’s labour, or the money he brings in to the household, then the cost of losing him is much greater. There are two ways she might lose him through extra-pair sex: if he has other sexual relationships he could run off with one of the other women, leaving his existing family in the lurch. But when she has extra-pair sex and gets busted, she might lose him. Or worse. Jealousy can trigger psychological abuse and violence.

In the recent paper that inspired this column, psychologists Michael E. Price, Nicholas Pound and Isabel M. Scott, from Brunel University in the U.K., sought to test the links between women’s economic dependence and both women’s and men’s attitudes to promiscuity.

From online surveys of more than 5000 Americans, Price and his colleagues showed that when the women in a subject’s social network depend economically on men, then subjects tend to judge promiscuity more harshly. And the effects weren’t spurious consequences of religion, or ethnicity or political conservatism. When they fitted these other variables into their statistical tests, the association between female economic dependence and opposition to promiscuity remained.

Price also asked whether the association arose as an artifact of geography: Texas and Utah, for example differ culturally on questions of morality and gender roles from, say, Massachusetts or California. States in which women earned more were also more relaxed about promiscuity. And this result arose out of the effects women’s earnings had on female economic independence.

Even more compelling, by comparing the attitudes of geographic neighbours, in the same or nearby zip codes, Price and his colleagues found that the association held. Irrespective of where you live, the economic dependence of the women a person’s social network predicts how they feel about promiscuity and non-marital sex.

We’ve known for some time that variation among societies in sexual morality is associated with variation in gender roles and, especially, earnings. The exciting development is how the new research suggests the patterns emerge from the bottom upward, with individual attitudes being shaped by prevailing economic circumstances in their close social network. At least in part.

I’m interested to know what the authors think about the relevance of their data to Roy Baumeister and Kathleen Vohs’ ideas on sexual economics in which women restrict the supply of sex under circumstances when they have the most to gain from a high price. This interpretation is not inconsistent with Price et al’s arguments about paternity certainty. But high female economic dependence presents exactly the kind of economic situation in which women need to drive a hard bargain in the sexual marketplace. Intriguingly, women took stronger anti-promiscuity stances, on average, than men did.

There are so many studies I would like to see done with a view to teasing out the causal relationships, and how attitudes to promiscuity change in the headwind of religion and other cultural forces. But this finding explains much about some of the trickiest ideological differences both within and among societies.

It could explain how economic changes since the Second World War paved the way for the sexual revolution. And why conservative politicians, especially in the U.S.A. seem equally hung-up on sexual liberty and the growing proportion of breadwinner moms.

And it may form an important ingredient in the ever-growing and dangerous ideological chasm between patriarchal theocracies and more gender-egalitarian democracies.

Thom Yorke singing Radiohead’s True Love Waits

P.S. I always relish seeing how other media cover research concerning issues touching sexual morality. According to “News Staff” at Science2.0, “If women want their promiscuity to be accepted they have to earn more money say evolutionary psychologists”. Keith Perry of the Telegraph reckons “Promiscuous women more likely to be tolerated if they are high earners”. And Lydia Smith, writing in the International Business Times got even more pithy, declaring “Only poor women are branded sluts”.

These were the first three links to news stories that popped up on Google. Not one headline reflects the real message of the study, but they all find a short path to slut shaming. For the record, the study tracked attitudes to women’s and men’s promiscuity.

The Conversation

Rob Brooks does not work for, consult to, own shares in or receive funding from any company or organisation that would benefit from this article, and has no relevant affiliations.

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Ovulatory overtures: do women’s preferences shift with their fertility cycle?

About a month ago, I stumbled across a paper that left me with the warm reinforcing glow that comes with being right. The rather artificial experiment played female subjects two pieces of music varying in complexity, and then asked each subject which of the male composers they preferred sexually.

All the subjects had to go on was the piece of music. Women at the fertile peak of their menstrual cycles preferred the composer of the more complex tune for a short-term thing. At other times, or if asked to rate the composers for suitability as a long-term mate, subjects showed no preference.

Does the attractiveness of musicians depend on the fertility of the beholder? Source: True British Metal/Flickr
Does the attractiveness of musicians depend on the fertility of the beholder?
Source: True British Metal/Flickr

My vindication was the paper’s support for the idea that music-making ability is preferred by those seeking mates. Such a preference is one possible way in which our ability to make and to appreciate music might have evolved, a position I happen to think is right. The paper’s test is pretty simplistic, but the addition of a new line of evidence gives the idea of sexually selected musicality another strand of support.

As a scientist I should be wary of my own reaction to the evidence. It is all too easy to count the “hits” that confirm one’s world view and ignore the “misses” that contradict it. Such confirmation biases build distorted and, left uncorrected, incorrect beliefs. They constitute the prime ingredient in religious faith and ideological zeal of all stripes. And science, done properly, is the only known antidote.

But what happens when science probes the most ideologically polarising questions themselves? Well, a very interesting case is unfolding right now concerning the science of how women’s fertility cycles shape their mating preferences.

Shifting cycles

The musical complexity paper builds on an idea in evolutionary psychology that women’s sexual preferences and desire “shift” at the time they are most likely to conceive, favouring men of superior genetic quality over the kinds of men likely to make good long-term partners and co-parents.

This “ovulatory shift” idea contains many moving parts, each of which has at least some support.

The best man to raise a child with is not necessarily the best available gene-donor. So women might profit, in evolutionary terms, from pairing up with a nice guy – hard-working and safe to be around – while discreetly also mating with a different, highly masculine, ridiculously good-looking paragon of genetic endowment.

Such liaisons come with risks, however, including being abandoned – or worse – by the cuckolded long-term partner. So it’s only worth “gene shopping” when you stand a good chance of conceiving.

The very idea makes many people squirm. But not everybody is squirming for the same reasons.

Mating preferences, and even how revealingly a person dresses may be influenced by where in her ovulatory cycle a woman is. This isn’t a popular idea with some ideologies and religions. Nathan Rupert/Flickr
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Social conservatives and religious traditionalists are often confronted by the sexual freedom and agency implicit to ideas like ovulatory shifts. It’s just too much to accept that some “good” women – wives even! – might play the odd away game for biologically rational reasons. Much easier to wash all that complicated evolutionary nuance away with a cleansing deluge of scriptural literalism.

Interestingly, evolutionary accounts of human behaviour come under equally heavy fire from the opposite end of the political spectrum, where biology can play no role in understanding society.

Cultural creationists, most of whom show no evidence of ever having attempted to understand evolution, prefer to flail at “biological determinism”. In their cartoon world, those wearing the white hats shoot from the hip at oppressive biological stereotypes, secure in the conviction that everything interesting about human behaviour arises as the results of learning, culture and social construction.

But here in the 21st century, serious academic research should be above the ancient laziness of pitting nature and nurture as competing alternative explanations. Unfortunately that habit remains too hard for some authors to break.

I’m certainly not claiming we shouldn’t be very careful about biological explanations. When it comes to women’s hormonal cycles, history shows the merit of treating biological claims sceptically. One can draw a straight line from Classical Greek ideas that the uterus wandered about the body causing all sorts of ailments to the popular diagnosis of “hysteria” for almost any psychological and many somatic complaints in 19th century Europe and America. The very word “hysteria” derives, after all, from the Ancient Greek for uterus.

Biological ideas are still widely used to confine and oppress women. Consider the recent controversial review of studies concerning mood and the menstrual cycle. Here at The Conversation, Jane Usher took that paper as reason to dismiss premenstrual moodiness as a myth. Jayashri Kulkarni responded that PMS is real and denying its existence harms women.

What about the evidence?

Whatever our political predispositions, surely we should be led by the evidence in deciding whether ovulatory shifts are real?

An impressive number of studies show that women in the “fertile phase” of their cycle express different preferences from those in less fertile phases and women on hormonal contraception. In particular, preferences for typically masculine male faces, behaviour, personality traits and health all peak in the fertile phase. And at peak fertility, women in long-term relationships more often report attraction to men other than their partners, and weaker attraction to their partners. Especially when those partners aren’t paragons of masculine attractiveness.

Many other studies, however, have found no evidence of ovulatory shifts. And who knows how many unpublished studies languish in researchers’ file drawers? This is just the job for a meta-analysis, the suite of statistical techniques for sifting a body of published results to extract the overall level of support for a hypothesis.

Recent months have seen not one, but two meta-analyses of the subject. One, led by Wendy Wood at the University of Southern California, concentrated only on preferences for high testosterone, masculine, dominant or highly symmetric men. Their meta-analysis of 45 published and 13 unpublished studies found no overall support for shifting preferences across the menstrual sample.

Across town at UCLA, Kelly Gildersleeve, Martie Haselton and Melissa Fales meta-analysed 134 effects from 38 published and 12 unpublished studies. In contrast with the USC paper, the UCLA team found robust cycle shifts when women were asked to assess men as short-term mates, but not when assessing long-term partners.

Two meta-analyses, published within months of each other, asking more-or-less the same questions, but getting different answers. That’s not how science – and meta-analysis in particular – is meant to work!

But, strangely, it’s not an unusual turn, particularly when the research concerns polarising issues. My good friend Michael Kasumovic pointed me to the following meta-analytic back-and-forth on the links between videogames and violence. His precis:

2001: Video games cause aggression.

2007: No, no, it’s a publication bias.

2007: See, it really is a publication bias.

2010: No! They really cause aggression!

2014: Actually, violent games increase aggression, and pro-social games increase prosocial behaviour …

… and so on it rolls. Meta-analyses of existing data do not provide the hoped-for panacea, much less change minds, particularly when the issues at stake are ideologically infused. At least not instantaneously.

This ovulatory shift story is far from done. The differences in sampling and analytic approaches between the two teams are still shaking out. I’ve been in touch with both groups and will shortly write another column trying to get to the bottom of how they reached such different conclusions. Before I do so, I’m waiting for one more paper to hit the presses, in order to be sure both teams have similar opportunities to present their cases.

Look who’s celebrating

For now, it remains worth asking what’s at stake. This rather intriguing business represents just the latest squall in the tempestuous relationship between the biological and social sciences. And it’s in danger of descending into rude tribalism.

Claims about ovulatory shifts are seen in some quarters as just another example of women’s cyclical biology being used to deny their agency and independence.
Wood’s meta-analysis invigorated anti-biology defenders of the faith. Consider Amanda Hess, whose Slate column often oozes thoughtful analysis. Whenever Hess strays near evolution, however, she becomes unwilling to weigh complex ideas on their merits. Her column on the Wood et al paper ran with a weak “patriarchal scientists don’t understand female bodies or the ineffability of culture” trope.

Her own biases confirmed, and making no mention of the earlier-published Gildersleeve meta-analysis, Hess rejoices that “a woman’s cultural conditioning is even more powerful than progesterone”. To pilfer an expression as hackneyed as Hess’ argument, 1975 called, and they want their false nature-nurture dichotomy back.

This kind of buy-in to outmoded all-biology-equals-determinism thinking seems so at odds with the way evolutionary psychologists and biologists really view behaviour. But look at what the journalists were working with. The press release USC put out quotes Wood:

A complete model of human reproduction needs to acknowledge women’s impressive capacity to regulate their own behavior and not fall into the trap of biological determinism […] Regardless of what might have been normative in ancestral history, with the advent of cultural roles and complex group living, women showed the capacity to tailor their reproductive activities to a variety of social roles.

Resistance to the notion of ovulatory shifts, then, springs from the fear that if hormones influence behaviour, then that robs women of their capacity to act independently and in their own interests. Claire Lehmann provides a scathing rebuttal of this argument, skewering wilful cultural creationist ignorance of how biology really shapes behaviour.

What fascinates me about this issue is how the anti-biology crowd are jumping at shadows. If evolutionary psychology conferences are secret gatherings of patriarchs out to perpetuate the status quo, then their cover is outstanding. What I see is a vibrant field concerned with the subtle ways in which women and men act in their own evolved interests.

Ovulatory shift research in particular, conducted by far more women than men, uncovers ever more intriguing nuances to women’s motives, actions and how they interact with deliberate and equally strategic behavioural self-regulation. Those most interested in gender equity and the liberation of female sexuality from that other – original – kind of creationism might well benefit by paying close attention to the field of evolutionary psychology.

Science is always done by people, and we all bring our own personal and scientific preferences and biases to the enterprise. What we do with those influences in the face of the evidence is what really matters.

The Conversation

Rob Brooks does not work for, consult to, own shares in or receive funding from any company or organisation that would benefit from this article, and has no relevant affiliations.

This article was originally published on The Conversation.
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What are the chances that your dad isn’t your father?

How confident are you that the man you call dad is really your biological father? If you believe some of the most commonly-quoted figures, you could be forgiven for not being very confident at all. But how accurate are those figures?

Questions of paternity are built over the deepest well of human insecurity, for children searching to know who they are, for fathers wanting to know whose kids they are raising and for mothers uncertain about the strength of the bonds holding their families together.

I consulted on an episode of SBS’s Tales of the Unexpected documentary series, “Who’s Your Daddy?” (screening this Sunday April 20) which looks at the issue in some detail.

The program explores the question of paternity certainty, combining three moving tales – each involving a DNA paternity test – with a poll of sexual behaviour in Australia and the US and an exposition of why uncertain paternity presents such a sensitive issue.

One of the three?

How many children are the genetic offspring of someone other than the guy who thinks he is the father?

 

If you have read, heard or watched anything on this question, you will have encountered many estimates, from 9% to more than 30%. The idea that almost one in three people might be the result of what we biologists rather matter-of-factly call “extra-pair copulations” titillates and horrifies in equal measure.

These estimates surprise most people when they first hear them. So much so that the numbers tend to stick in our minds. But do these numbers bear any truth?

The problem with most data on paternity is the near impossibility of obtaining an unbiased sample. A paternity clinic, for example, is a bad place from which to estimate the rate of misattributed paternity. Many clients are there because at least one party isn’t convinced.

Likewise, any study recruiting families – however randomly – might have more success recruiting mothers who harbour no doubts about their children’s paternity.

Questionable figures

Swinburne University sociologist Michael Gilding, who also appears in the SBS program, has thoroughly researched the origins of the popular belief that 10% to 30% of paternities are misattributed.

He traced the source of the high estimate – 30% – to the transcript of a symposium held in 1972 in which British gynaecologist and obstetrician Dr Elliot Philipp mentioned an estimate from a small sample of parents.

This brief conversation took on a life of its own, despite the fact that Dr Philipp never published the findings of his study. As a result, his precise tests and his population sample were never identified.

Of the many studies that have attempted to estimate the rate of misattributed paternity, the higher estimates have tended to grab headlines, whereas more modest estimates sink without trace.

In whose interest?

Prof Gilding implicates two groups for inflating the public perception of misattributed paternity rates: evolutionary psychologists and fathers’ rights groups.

Evolutionary psychologists, according to Gilding, are so invested in their ideas about the nuanced mating decisions women make that they overestimate how often women mate outside their long-term relationships. My impression is that this may be an accurate assessment of some headline-grabbing research but not universally true of the field.

Fathers’ rights groups represent men negotiating the heartbreak of family break-up. Some such groups also host strident activists propelled by a conviction that the law and society have been utterly corrupted by feminism, gynocentrism and misandry.

The blogs and forums of this netherworld amplify any finding, however flimsy, implying that women are rampantly promiscuous or cynical swindlers looking to part men from their hard-earned cash or dupe them into caring for kids that don’t bear their DNA.

They call this “paternity fraud” and some claim it “worse than rape”.

You won’t find on their websites a critical analysis of the sampling methods or techniques used to estimate paternity misattribution rates, just titanium-reinforced convictions that 25% to 30% of children are being raised or supported by the “wrong” guy.

Why does it matter?

In the ever-dynamic game of sexual relations, the one factor that has always weighed decisively in the favour of womankind is the secure knowledge that she is the mother of her children. According to an old aphorism: “Maternity is a matter of fact, whereas paternity is a matter of opinion.” At least it used to be.

Paternity testing now much easier and cheaper.

Fast-moving developments in molecular biology make paternity testing faster, cheaper and more accurate than ever before. Analysis of foetal DNA in the mother’s blood enable paternity assignment as early as eight weeks into a pregnancy.

Interweaving strands of evolutionary research suggests that paternity confidence forms part of the glue bonding men to their children and to the women who bore them. Undermine that confidence and men invest less readily in the subsistence and safety of their families, and become more likely to abscond.

That is not to say that all men are calculating Darwinian cynics. Many men make magnificent fathers to children that do not bear their DNA. But men get immoderately touchy about paternity. Insecurity over paternity has tectonically shaped much that is least admirable about male behaviour and twisted societies.

But knowledge about paternity can be empowering. It can reassure an uncertain father. It can vindicate an impugned mother or assist her in a paternity suit. And it can help a child understand who they are and where they come from.

What’s the answer?

So how many children are sired by someone other than “Dad”?

Population-wide random-sample DNA testing remains financially and ethically unviable. But to understand some of the behaviours that might lead to paternity misattribution, the SBS documentary producers commissioned Roy Morgan Research to poll samples of Australian and American women.

They asked a number of questions including whether they had conceived a child at a time when they had multiple sexual partners? I was surprised that no more than 2% of women admitted to this.

That suggests a low rate of misattributed paternity; but note the data are presented per woman, not per child. The poll does suggest that mating with multiple men around the time of conception is neither rampant nor pathologically rare.

These results marry comfortably with DNA estimates of misattributed paternity from samples that cross a broad range of societies which suggest the rate is between 1% and 3%, and with Prof Gilding’s estimate of between 0.7% and 2%.

The number of children whose biological father isn’t their social dad is probably far smaller than you’ve been led to believe, although the 30% figure seems to be a zombie-statistic that refuses to die.

But even a 1% rate of misattributed paternity still adds up to millions of individual children, world-wide, each part of an interesting, sometimes tenuous and often heart-breaking story.

The Conversation

Rob Brooks receives funding from the Australian Research Council. He consulted, without remuneration, with the production company (Cordell Jigsaw Zapruder) on the design of the paternity poll and the content of the show, and appears in the program mentioned here.

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Don’t fear the patriarchy, girls. Just keep your knickers on!

There’s a video out there on the intertubes that’s got conservatives cheering and lefties in a lather. Actually such videos are legion, but I’m talking here about a particular one with the rather broad and even-handed title of The Economics of Sex.

You can watch it, but I must offer a trigger warning that people who have ever had sex before marriage, or know someone who has, might find its pure, unadulterated truth-bombiness a little too much for their besmirched souls to withstand.

If you can’t bear to watch, here is a very brief precis of the argument:

  • marriage rates in the US are down. Like, worse than the Dow!
  • to understand this calamity we need to know more about the economics of sex
  • men have higher sex drives than women. That’s just the way it is
  • which makes sex a resource controlled by women. Always has been
  • sex is cheap these days – because the pill largely freed women the cost of becoming unexpectedly pregnant. Lower costs = more supply = lower prices
  • this created a “split mating market” – on one side, people “only interested in sex”, and on the other, people “largely pursuing marriage”
  • there are too many men in the sex market, so women can call the shots
  • but women outnumber men in the marriage market, putting blokes in the drivers’ seat
  • it’s always been up to women to set a high market value for sex by restricting supply
  • this unspoken female pact to set a high market value for sex has all but vanished: women compete for men by hopping in the sack with them, thus lowering the ‘price’
  • which is why Americans are less likely to marry, and do so later in life than ever before
  • if women just resume colluding to set a high price for sex, then men will be nicer, take women on more expensive dates, buy bigger diamonds and get busy marryin’
  • and then balance will be restored to the force.

Qualified admiration

This is a slick piece of strategy. It combines the electronic reach of the internet with a funky old-skool brown-paper and texta visual device sure to appeal to all those youngsters stumbling haplessly onto the sex-marriage market. Not so sure about the Sinatra backing tracks, but love and marriage certainly do go together like a horse and carriage. At least they did, back in Ol’ Blue Eyes’ day. Except when they didn’t.

Strategy? What strategy?

The video is a product of the Austin Institute for the Study of Family and Culture a Texas-based think-tank whose mission is “to be a leading resource for tested, rigorous academic research on questions of family, sexuality, social structures and human relationships”. By which they appear to mean research in favour of families with one father married to one mother (preferably stay-at-home).

The brains behind the Institute, according to the Austin Chronicle happens to be one Mark Regnerus, a darling of the pro-marriage (as long as its not gay marriage) right. Regnerus achieved fame/notoriety in 2012 for his New Families Structures Study of young adults who were raised by parents in gay relationships, compared with ‘still-married’ parents. And he’s not so keen on upwardly-trending masturbation tendencies, either.

Who ever said there’s no such thing as a conservative Christian sociologist?

The bulk of the video relies on Timothy Reichert’s economic argument that the contraceptive pill, in reducing the ‘price’ of pre-marital sex, has favoured mens’ interests at the expense of womens’. Reichert’s article, published in the religious organ First Things, even finishes with some helpful suggestions about the future of feminism:

What is needed is a movement of “new feminism” based on a deep understanding of the nature of woman and her role at the center of society.

Riechert and Regenerus’ ideas about a mating market cleft – by the pill – into those seeking sex and those seeking marriage, has long been popular with conservatives. Our very own Cardinal George Pell built an op-ed in The Australian around his work, lamenting the transformation 50 years of the pill had rent upon a formerly chaste and god-fearing society.

Suppression of female sexuality

The bit that interests me most about this video, however, is the way Regnerus uses an important 2002 paper by the psychologists Roy Baumeister and Jean Twenge with the title of The Cultural Suppression of Female Sexuality. It doesn’t take much perspicacity to see that where sexual activity – from masturbation to extra-marital activity – is suppressed, women and girls bear much more of the cost than men and boys.

It might seem logical, then, to assume that sexual suppression is something men do to women; that it embodies patriarchal control of female sexuality. Yet Baumeister and Twenge present an impressive body of circumstantial evidence that women enthusiastically engage in policing one another’s sexual activity. From slut-shaming to female genital mutilation, the chief antagonists are often women.

The rationale? That if a majority of women restrict the supply of sex, then all women can drive a harder bargain on the marriage market. When women who engage sexually with a speed or abandon that exceeds the cultural norm get branded ‘cheap’, it isn’t a metaphor.

This idea that women control the price of sex like an unscrupulous cartel is an important one with many implications for our understanding of sexual behaviour and relationships. My reading of the evidence suggests that it is probably true. But that is not to say it is the only dynamic feeding the suppression of female sexuality. Many old ideas about the involvement of men, particularly husbands and religious leaders also appear to have strong support.

This is a very exciting and hotly contrested area of research right now. So I was struck by the sheer audacity when (6:35) the peppy female narrator confidently piped:

Here’s the thing: In the past it really wasn’t the patriarchy that policed women’s relational interests. It was women.

Yep. If women just collectively kept their knees together, they’d all find it easier to ensnare a guy who’d willingly fork up two months’ salary to another cartel – the deBeers diamond company – for a great big diamond ring. And then, as if in a Disney movie, all the bad magic wrought by the pill, including declining marriage rates and …. men playing video games …. would be magically erased.

It’s the end of the world as we know it (and I feel fine)

Sneer as I might, there are interesting research questions embedded in this piece of conservative propaganda and in Regnerus’ research in general. I’m actually happy to entertain the idea that a loosening of cultural suppression of female sexuality may be driving the reduction in marriage rates. And possibly even the drift away from religion. But I’m interested, too, in the broader implications of what it all means.

Regnerus quite astutely summarises the conservative fears that underpin their deep hang-ups with female sexual freedom and the effect it has on supply, when he writes, in Slate:

Don’t forget your Freud: Civilization is built on blocked, redirected, and channeled sexual impulse, because men will work for sex. Today’s young men, however, seldom have to. As the authors of last year’s book Sex at Dawn: The Prehistoric Origins of Modern Sexuality put it, “Societies in which women have lots of autonomy and authority tend to be decidedly male-friendly, relaxed, tolerant, and plenty sexy.” They’re right. But then try getting men to do anything.

You don’t have to be a marrow-deep sexist to embrace this position. The psychoanalyst Mary Jane Sherfey, who bore the wrath of her male colleagues in emphasising the power of the human female sex drive and in questioning Freud’s insistance of the primacy of vaginal (over clitoral) orgasms, argued that suppressing women’s powerful, innate, sex drives was an essential stepping-stone to the success of agrarian societies and thus the rise of civilization.

And yet this idea that sex must be suppressed or all will be chaos hasn’t a whole lot of objective support. It seems to me to be a re-stating of an ancient bias – one that favoured older, wealthier men.

Since at least the dawn of the Roman republic, and probably well before that, conservative leaders have insisted that sexual liberty was the first step toward the end of civilization. The chastity of the Vestal Virgins was considered Rome’s primary safeguard against its enemies. How different is that from Reverends Jerry Falwell, Pat Robertson and Rabbi Noson Leiter blaming calamities like Hurricane Katrina and 9/11 on “abortionists, […] feminists, […] gays and the lesbians”?

It doesn’t seem like it should be controversial that all people – not just women – are better off in post-enlightenment wealthy societies where effective medical interventions limit deaths in childbirth, where women can make their own decisions about how many children to bear and when to have them, and in which people have greater choice about when to leave a dysfuntional marriage or whether to enter one in the first place. As Michelle Goldberg puts it, in her exceptional book, The Means of Reproduction, “there is no force for good as powerful as the liberation of women”.

And yet it is controversial. Regnerus and the Austin Institute want the suppression of female sexuality back, and they want it back badly. Women, they argue, should be doing it for their sisters. Now how far they want to wind the clock back they haven’t stated. Apart from the pill, which other forms of female suppression would they like to revoke? Voting rights? Laws against witch-burning?

The great R.E.M. in one of their finest moments. I’ve always loved Mike Mills’ backing vocal “It’s time I had some time alone”.

Rob Brooks does not work for, consult to, own shares in or receive funding from any company or organisation that would benefit from this article, and has no relevant affiliations.

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