(I am republishing a lot of ‘legacy content’ from our PLOS Neuroanthropology weblog, which has been taken down, along with many of the other founding PLOS Blogs. Some of these, I am putting up because I teach with them. If you have any requests, don’t hesitate to email me at: greg.downey @ mq (dot) edu (dot) au. I suspect many of the links in this piece will be broken, but I will endeavour to try to slowly rebuild this content. I originally published this on 5 April 2014.) 

By Greg Downey; (long read: 5500 words)

Moulay Ismail ibn Sharif succeeded to the sultanate of Morocco after his brother fell from a horse and died in 1672. Twenty-six when he became the Sharifian Emperor, Moulay Ismael “the Bloodthirsty” — as he was called — went on to expand his holding in a remarkable reign. His armies conquered neighboring territories and fought off the Ottomans (eventually forcing them to recognize Moroccan independence), and the emperor went on a building spree to make Meknes a rival to Versailles, with French engineers to help.

Moulay Ismael also had a prodigious capacity for cruelty. He legendarily ordered that the walls of Meknes be decorated with the heads of 10,000 enemy soldiers. He also sponsored the Barbary pirates, who engaged the states of Europe in a protracted and costly low-grade war, drove the American colonies to form the first navy in North America, and pushed the English and Spanish from Moroccan territory.

But Moulay Ismael is probably best known to history because of his prodigious capacity to reproduce. The emperor had a thing for children,… well, for having sons, that is.

According to the Guinness Book of World Records, Moulay Ismael, with four wives and at least 500 concubines, sired an estimated 1042 children (they recently raised their estimate from 888). That feat is even more incredible when one notes that Moulay Ismael, demonstrating just how deep his cruelty went, ordered that all the female infants of his concubines be smothered when they were born by their midwives.

A recent paper by Elisabeth Oberzaucher and Karl Grammer (2014) in PLOS One set out to test whether the number of children attributed to Moulay Ismael was even plausible. They used a number of computer simulations, taking into account a range of estimates of human fertility, to see if one man could in fact sire so many children.

More specifically, the two researchers from the Department of Anthropology at the University of Vienna tested the claims of French diplomat Dominique Busnot, who on a visit to Morocco in 1704, when Moulay Ismael was 57 years-old, reported that the emperor had six hundred sons. Was it plausible for the emperor to have had six hundred sons — as well as all the daughters who would have been killed at birth — during a period of thirty-two years (from taking the throne at age 25 until Busnot’s arrival)?

The question is important, not merely to establish how much sex would have been necessary to achieve this extraordinary level of reproduction — once a day? twice a day? — but also because it suggests a theoretical limit to male fertility.

The case of Moulay Ismael’s harem, as Oberzaucher and Grammer note, is widely cited in ‘textbooks on evolutionary psychology and biology’ (2014: 1; for an online version, see Jerry Coyne’s blog, Why Evolution Is True). The alleged number of Moulay Ismael’s progeny is important for our understanding of human reproduction and sexuality, especially from an evolutionary perspective.

• Although this is a stand-alone piece, I’m trying to return to a discussion I posted a couple of years ago on the ‘long, slow sexual revolution.’ So this is a kind of Part 2-ish of that piece (although not  as long). Since my approach to blogging has changed since that first piece, and my own thinking on human reproduction and evolution, this piece will focus a bit more narrowly.

How plausible is Emperor Moulay Ismael?

Oberzaucher and Grammer decided to test only the number claimed by Busnot in his first visit to Morocco in 1704 because Busnot’s account is the most complete, and there’s clear data for the relevant reproductive lifespan. As the researchers point out, however, because of Moulay Ismael’s infanticide of daughters — only the daughters of his four wives were allowed to live — we have to assume that his fertility was much higher than the total number of children reported by Busnot. They suggest that the estimate to test is ‘approximately 1171 children from 500 women in a reproductive time span of 32 years (25–57)’ given the expected male-female ratio of offspring (ibid.). Could one man have done this?

Of course, experimental methods of testing the limit of male fertility are sort of out of the question, so the historical cases of extreme reproduction like Moulay Ismail and Genghis Khan are extraordinarily important. But because these historical accounts are subject to all sorts of biases, the computer simulation route seems to be one of the few ways to test the claims made in these records.

Einon (1995), for example, claims that Busnot’s account is not plausible, based on a set of assumptions about sperm survival, female infertility rates, likelihood of conception, and chances of spontaneous miscarriage. Gould (2000) countered that Moulay Ismael in fact could have produced the hundreds of children attributed to him by contemporary accounts; according to Gould, Einon underestimated potential fertility due to a number of incorrect assumptions, including the fertility of young women, the length of time sperm could survive after ejaculation, and even the number of years available to Moulay Ismael for reproduction.

Virtual Moulay Ismael — extreme fertility simulators

To test the claims about Moulay Ismael, Oberzaucher and Grammer had to extrapolate from fertility models based on very different conditions. That is, most of what we know about fertility was not learned in the context of what we might call ‘extreme polygyny’. The researchers used three different models of fertility, all based on longitudinal data from couples in long-term relationships trying to conceive.

Using a range of conservative assumptions in these models, Oberzaucher and Grammer ran the three different simulations to test, first, how many times would a man have to copulate each day to reach the target (1171 offspring in 32 years) and, second, what number of offspring would be reached in 32 years under a range of conditions. As they write:

We reran the simulations four times, once with ovulation detection and without sperm ageing, once without ovulation detection and sperm ageing, once with both, ovulation detection and sperm ageing, and once with sperm ageing and without ovulation detection.

Sperm ageing was a crucial variable because it gradually decreases the chance of fertility. In those simulations with ‘sperm ageing,’ Oberzaucher and Grammer adjusted the chance of conception downward by 1.52% per year. Because they ran simulations both with and without a variable for sperm ageing, the research shows how this factor might influence overall male fertility.

‘Ovulation detection’ likewise is key because it would theoretically make conception more likely, driving up fertility (assuming that Moulay Ismael actively sought to produce children). Although ovulation detection is possible through testing a woman’s vaginal mucous, Oberzaucher and Grammer didn’t know if any form of this technique occurred during Moulay Ismael’s reign.

Even without knowledge of the symptoms of ovulation, ovulation detection effects may also result unconsciously if ovulating women are more attractive to their partners, or seek intercourse more actively, as some research in evolutionary psychology suggests. Even religious or cultural constraints on intercourse with women during their menstrual periods might affect overall fertility as any menstrual taboo would lead to Moulay Ismael copulating more often with women in his harem during their window of greatest fertility. So modeling some effect for ovulation detection can make sense in a number of conditions.

Using a range of variables, Oberzaucher and Grammer find that it would have been possible for Moulay Ismael to have 1171 children; two of the models require, however, that he had sex around three times every two days, and that taboos on menstrual periods were in place, to really be plausible. Intercourse might have been less frequent if his wives and concubines experienced heightened fertility due to the emotional arousal of infrequent intercourse, as research on the wives of German soldiers during World War II suggested (they only had intercourse infrequently when their husbands had leave from the front) (see Oberzaucher and Grammer 2014: 2-3).

Depending upon the model and assumptions, ovulation detection can be particularly important, especially if decreasing male fertility is taken into account. If the potency of sperm decreases, choosing the women with which to use the shrinking resource (pun intended) grows in importance. Moreover, if sperm ageing is taken into account, heightened fertility rates — like those in the wives of German soldiers — become increasingly important to the simulation achieving the fertility goals.

Betzig (1992) reports that the Chinese emperor Fei-ti, one of the other men with the largest recorded harems, confined sexual contact with his wives and concubines to the fifth day after menstruation, suggesting that his contemporaries had some basic understanding of female fertility (as well as damn good bookkeeping for menstrual cycles; see Einon 1998: 415).

Dorothy Einon (1998) discusses how Moulay Ismael’s senior-most wife allegedly controlled who he slept with, although we don’t know if she had a pattern of selection that would have made the emperor more likely to encounter fertile partners. Einon (ibid.: 422) estimates that, if Moulay Ismael mated randomly with a chaste woman from his harem — avoiding her period of menstruation — he stood a 15.2% chance of meeting a woman at optimal fertility. (Oberzaucher and Grammer 2014 argue that she underestimates fertility, but that’s not terribly important for my purposes; check out their article if you want more.)

The bottom line though is that Oberzaucher and Grammer find that, even with fairly conservative estimates: ‘results indicate that the Emperor could have reached his notorious reproductive success with fewer copulations than assumed so far – thus the historic reports could be facts and not fancy’ (ibid.: 4). He would have had to be pretty damn determined, and remarkably persistent for three decades, but the number of children attributed to him by Busnot is at least plausible.

Possible complications

Paternity is one possible issue that could complicate the number of Moulay Ismael’s children. Moulay Ismael took extreme steps to ensure his paternity of all of his sons: he personally strangled any wife or concubine suspected of adultery, or he had their breasts cut off or their teeth pulled out. Men who looked at one of his concubines or wives were liable to be executed, even after the women were retired from his harem at age 30.

Although there might still have been some children in this group of 1171 with paternity other than the emperor, it’s probably safe to say that Moulay Ismael’s measures were among the most severe controls ever exercised over a large group of women’s fertility.

Another complication is, as Oberzaucher and Grammer put it, ‘love and favouritism’ (2014: 4). Most of their models treated the choice of partner as random. If Moulay Ismael began to favour one partner or another, his attempts to conceive could become non-random, or he could repeatedly have sex with one or a small number of his partners, and the total number of successful attempts would decrease. In other words, attachment costs fertility if you’re a bloodthirsty (and child-hungry) emperor. ‘Love’ or loyalty (or anything like them) can be a liability for overall fertility. Judging from what we know about Moulay Ismael, I suspect he wasn’t hampered too much by an over-abundance of attachment.

Another possible complication that Oberzaucher and Grammer mention, but don’t discuss in any length, is whether sperm potency is affected by frequent intercourse (2014: 2). Although they suggest that it’s not likely, I’m not convinced that we know, really, how frequent intercourse with a large number of different women would affect a man’s sperm count, potency, or other dimensions of ejaculation. There simply is no comparable case where research has been done, to my knowledge. Is there any ‘training effect’ on the testes? Do metabolic mechanisms that lead to higher sperm count during intercourse in humans when the partners have been separated (and thus there’s a chance of cuckoldry) become more pronounced in these extreme conditions? I wouldn’t rule it out, even though I suspect that there’s a limit to testicular ‘trainability’. Certainly, early research by Freund (1963) suggests that men cannot increase their ‘daily sperm output’ even with a substantial increase in the frequency of intercourse.

But women’s bodies, too, complicate the estimate because lower frequency of copulation can lead them to have longer, more irregular menstrual cycles (see Einon 1998). We also don’t know for certain what sort of diet the women in his harem had, and whether they were really getting sufficient nutrition to maintain peak fertility.

Why Moulay Ismael matters: parental investment theory

Admittedly, the case of Moulay Ismael the Bloodthirsty is interesting in and of itself. But his example is also important — and he gets discussed in contemporary literature in evolutionary theory — because he highlights potential male-female differences in human reproduction, and the likelihood that diverging strategies might arise in the sexes. Moulay Ismael, for some evolutionary theorists, represents not an aberrant, infamous abuse of power but rather the logical outcome of a particularly male reproductive strategy based on our reproductive biology (see, for example, this piece by Satoshi Kanazawa on why he argues mothers are better parents — spoiler: because evolution said so!).

Robert L. Trivers (1972), arguably among the most influential evolutionary theorists after Darwin, helped to outline the implications in his theory of ‘parental investment.’ Trivers suggested that the enormous disparity in the cost of reproducing between men and women meant that women’s and men’s reproductive strategies necessarily had diverged. The number of potential children, the energy cost of each offspring, and the frequency of reproduction possible led to profoundly different ‘investment’ demands for successful reproduction from each parent.

Parental investment theory highlighted that women could reproduce only slowly, as each child became increasingly independent. From conception, through pregnancy, with added time out for lactation amenorrhea (the period of decreased fertility from regular breast-feeding), our female ancestors probably had a birth-spacing of between three and six years.

A man like Moulay Ismael, in contrast, could reproduce much more frequently, if he could gain access to many mates. A man need invest very little in an offspring to pass on his genes — if someone else could be counted upon to raise and support his children. In contrast, women must invest much more: not just the nine months of carrying the child to term as well as the metabolic demands of nursing the infant, assuming that she could not get someone else to take over child-rearing, but even at the microscopic level of the biological contribution of gametes in conception.

Parental investment in miniature: anisogamy

At this microscopic level, the principle of anisogamy highlights that parental investment is unequal from the moment of conception. Anisogamy is asymmetry in the biological contribution of men’s and women’s bodies in conception: the idea that eggs are costly, and sperm, cheap. Anisogamy is central to most accounts of sexual differences in reproductive strategies (as well it should be).

A variety of contrasts characterize anisogamy: the ovum is the largest cell in a human body, and a sperm the smallest. Women release only one or two eggs during every menstrual cycle, or around twenty-nine days (with great variation), whereas men can relatively quickly ‘reload’ to make another attempt at reproduction. In fact, every ejaculation of a healthy male will have around 250 to 300 millionsperm, although sperm count varies significantly. Up until about a year ago, it was virtually dogma to assume that women simply could not produce any new eggs during their lifetime, their supply slowly dwindling as the ‘biological clock’ on reproduction ticked down to senescence (see Wood, et al. 2012).

Many analyses of differences between men’s and women’s approaches to reproduction point to anisogamy, the larger ‘investment’ per gamete for women, as the most important dimension of male-female difference for understanding sex differences in mating strategy. As psychologist Dorothy Einon wrote:

In the time taken for a woman to complete the menstrual cycle that releases one ovum, a man could ejaculate 10 to 100 times. During the complete female reproductive cycle of 3 to 6 years, this figure could extend to thousands more ejaculations. It is this discrepancy in the frequency of releasing fertile gametes that lies behind claims that “most males can raise their reproduction by mating with many females” (Betzig 1992) and a “really reproductively successful son may grow up to father hundreds (thousands?) of children by hundreds (thousands?) of women” (Betzig 1997).

(See also a TED talk about ‘wild sex’ that I really love, in which Carin Bondar suggests that the fact that ‘sperm are cheap’ leads to an overall ‘more sex is better’ approach to reproduction in men).

Some evolutionary theorists even suggest that male fertility is potentially limitless, which is why Moulay Ismael is so important. (See  Shackelford and Goetz 2009, and Togashi and Cox 2011 for a much more thorough discussion of the biology and evolution of anisogamy and sexual conflict in human reproduction.)

Anthropologist Kate Clancy compares anisogamy-based stories of human human sexuality and evolution to the predictable permutations of stories told by her three-year-old daughter. As Clancy describes, although her daughter’s stories have permutations and little wrinkles, they always follow ‘the same, uncomplicated arc’ involving a small cast of characters — Kate’s daughter, Kate, Dora and Diego — a net, and ‘Rescue Scissors.’ Clancy explains that ‘the framework borrowed heavily from one of the few mythologies known to my little girl: Dora the Explorer.’ Likewise:

Evolutionary psychology is often a kind of story-telling, and instead of borrowing from a preschool cartoon they borrow from the concept of anisogamy. Anisogamy is sexual reproduction formed by unequal gametes, in our lineage a big egg made by females and little sperm made by males. This provides the foundation for differential reproductive investment, where females often put in the time and effort of gestation, lactation and care. From here, proponents of EP see essential differences between what men and women want in relationships, and the kinds of relationships that are optimal, and a model this broad makes it possible to shoehorn any behavior into its adaptive framework.

The case of Moulay Ismael is important in this context because he seems to sketch out the limits of male fertility in practical terms and thus at least one of the limits of anisogamy as a theoretical explanation. (If you want more on sexual dimorphism and physiognomy, Patrick Clarkin’s series of human sexuality is great; this link is to part 4, on promiscuity and physiology)

The limits of male fertility: why not more than 1171?

The brute numerical comparison of egg and sperm — the more than 100-million-fold difference in the number of gametes — as a measure of parental investment asymmetry is misleading on a few levels. In the wild, sperm only really work in packs. Mobs really.

Davies and Shackelford (2008), for example, point out that males in a variety of species may have to produce so much sperm in order to reproduce successfully that the overall metabolic investment in the fertilized embryo may be higher for them than females with egg production.

The WHO has recently placed the lower limit of ‘normal’ human sperm concentrations at 15×10⁶sperm/mi;liliter of semen, down from the old recommendation of 20×10⁶ sperm/ml; with the average ejaculation from 2 to 6 ml (Cooper et al. 2010). (Note that this change in the definition of ‘sub-fertility’ in men is itself controversial.) That would mean the lowest limit of health ejaculation would be around 30 or 40 million sperm, with more likely levels being around 280-480 million sperm per ejaculation (see Ryan & Jethá 2010). The number is staggering compared to the one, or at best two, eggs that are released at ovulation, but so is the number that is effectively ‘subfertile’ in men.

Sperm concentration drops off if a man has sex frequently, although I’ve found good recent research on this surprisingly difficult to come by. Bulls’ sperm production is way better understood.

Oldereid and colleagues (1984) found, in subjects asked to ejaculate every eight hours, that sperm count plummeted: starting at an average close to 300 million per ejaculation, concentrations dropped off to around 100 million on the second sample and even lower on subsequent samples. Averages from the third ejaculation on were at 50 million or lower — bouncing around fairly close to that ‘infertility’ level.

When Valsa and colleagues (2012) tried to investigate the effect on sperm of more frequent ejaculation — every four hours — they simply couldn’t get subjects to complete the experiment. Five of the eleven subjects dropped out after the third sample (that is, after eight hours,). Only one man managed to submit five samples in sixteen hours. The rest had discontinued due to ‘physical exhaustion.’ By the third sample, sperm count was bottoming out and didn’t rebound.

Historical records of extreme harems corroborate this insight in unusual fashion; some Chinese emperors, who themselves had quite large harems, allegedly reported that the sexual servicing of their harems grew oppressive (cited in Einon 1998: 416). Although having sex once or more times each day may not sound terribly ‘onerous,’ to get to over 1000 children, we’re talking about the ultra-ultra-marathon of male reproduction: decades of averaging these rates of intercourse, even with aging and periodic illness.

In classic work on the topic, Freund (1963) found that increasing a man’s ejaculation rate from 3.5 to 8.6 times per week (I’m not sure why the decimal places) led to a decrease in the total amount of sperm that men produced, even though the total volume of semen increased. So sperm concentrations dropped faster than overall sperm count. In fact, Freund found that a rigorous period to ‘deplete’ reserves of sperm led the men to lower levels of sperm output, even after more than 150 days of recovery!

One of the biggest limits on male fertility, however, is the peculiar form of female fertility in humans. That is, because women conceal when they are fertile and mate when they are not (unlike many animals), human males end up having a lot of sex that can’t lead to offspring. Einon (1998) points out that, because women’s bodies conceal ovulation, in took scientists until the 1920s to figure out the female hormonal cycle and the peak of fertility.

In other words, the idea that male fertility is practically infinite due to the hundreds of millions of sperm in a normal ejaculation is not really accurate. It may make for good science fiction, but it makes for lousy evolutionary theory. Hundreds of millions of sperm in an ejaculation — the brute fact of anisogamy — does not help us to understand the real trade-offs that determine male fertility and mating strategies unless we take into account a variety of other factors. That’s where Moulay Ismael, both the historical figure and the virtual model, comes in.

The long tail of reproductive success

One of the more interesting little insights turned up by Oberzaucher and Grammer’s Moulay Ismail simulators is that most of his harem, from the point of view of maximizing reproduction, was superfluous. They found that:

With our simulation we could also provide evidence that the harem size is of lesser importance for the achievement of the reported reproductive success than thought so far. A breeding pool of 65 to 110 women leads to the maximum reproductive outcome. This highlights the importance of incorporating cost-benefit calculations – increasing the size of the breeding pool beyond that point increases the costs without additional benefits to outweigh them. (Oberzaucher and Grammer 2014: 4)

In other words, at least according to the simulation, Moulay Ismael demonstrates that the unlimited fertility of men is a myth. If anything, his harem squandered a significant part of his wives’ and concubines’ potential fertility. Of course, having a harem of more than 110 women still has reproductive consequences, as the researchers suggest:

Having a harem of 500 concubines might have been due to other considerations than maximization of individual reproductive outcome. For example, it could have been a means to remove the additional women from the reach of other men, thus depriving them of reproductive potential. (Oberzaucher and Grammer 2014: 4)

Although as a personal reproductive strategy, the Moulay Ismael ‘only-I-get-to-make-babies’ approach might be a winner, as a group’s reproductive strategy, it’s terrible.

If anything, Moulay Ismael’s extreme polygyny put a huge dent in the overall fertility of his capital city. The average fertility rate for the women in his harem was much lower than it would have been had they been in much-less-polygynous mating relationships. Even more dramatically, in order to maintain a rolling harem of 500 women under 30 — when they were forced to ‘retire’ — some estimates suggest that he would have had to have amassed over four thousand wives and concubines over his lifetime. Given that it was a capital offense to have sex even with a former member of his harem, this puts his alleged fertility in a whole new light. Against this number — four thousand women — 1171 children is actually a staggeringly low rate of fertility, a measure of how inefficient a single man is at making use of the fecundity of a large number of women.

When I wrote about this in my little ebook on human evolution (Becoming Human, free from Apple’s iBookstore or in a variety of formats from Smashwords), I contrast Moulay Ismael’s reproductive inefficiency with the case of the wife of Russian man, Feodor Vassilyev. We don’t even know her name because no one recorded it, but Mrs. Vassilyev gave birth to 67 children during her lifetime, including sixteen sets of twins, seven sets of triplets, and four sets of quadruplets.

Compared to the women in Moulay Ismael’s harem, whose lifetime fertility averaged less than a single child for each woman, Mrs. Vassilyev is a demographic force, with a reproduction rate over 200 times higher (with Moulay Ismael’s likely four thousand wives and concubines responsible for .3 child/woman). A population that reproduced like Moulay Ismael would quickly be overrun by a population that bred like the Vassilyevs (granted, both are impossible).

(Please note, I realize that Moulay Ismael is actually alleged to have produced more children subsequent to Busnot’s account, but I’m just trying to keep this fairly straightforward. Even if we allow for a lifetime fertility rate in the harem of .5 child/woman, the gap between Mrs. Vassilyev and these women is still well over 100 times greater lifetime fertility, assuming that wives and concubines of Moulay Ismael didn’t go on to reproduce more after they left him.)

What does Moulay Ismael really teach us?

To me, the extraordinary reproductive monopoly that Moulay Ismael demanded, and his impressive, albeit inefficient output of offspring, doesn’t really offer an unobstructed view of unfettered ‘human nature’ any more than the prodigious maternal accomplishments of Mrs. Vassilyev do. Both staggering feats of reproduction demonstrate that human fertility is not simply constrained by the supply of eggs or sperm. Other limits are just as crucial, including both metabolic and social factors. Most people get nowhere near their maximum theoretical fecundity.

The kind of reproduction Mrs. Vassilyev achieved was only possible given a sedentary, agricultural life style, with enormous support to provision for all her offspring, including probably from her own children. Likewise, Moulay Ismael’s reproductive success didn’t just depend upon his longevity and the remarkable durability of his testes, but also upon the social and political organization that went into his conquests and empire building, as well as a lot of naked coercive power.

You could say that it took him an army of 100,000 soldiers to have 1000 children (and probably a whole bunch of eunuchs to make sure that the 1000 were, in fact, his).

Both Mrs. Vassilyev and Moulay Ismael could only accomplish what they did because human reproduction broke many of the constraints that limited the birth rates and fecundity of other great apes, setting our human ancestors on a quite different course of reproduction.

To really understand human reproduction in evolutionary perspective, you can’t just compare men and women; you have to also compare humans to non-humans, especially other primates.

Human birth spacing

Human birth spacing is kind of strange relative to other great apes. We have the most immature, dependent young among modern apes; our lifestyle is so dependent on learning and complex skills that, in foraging groups for which we have clear data, individuals are not producing more calories than they are consuming until well into the second decade of their lives. The threshold of self-sufficiency takes us much longer to cross than other apes, so we might expect long periods of maternal dependence in our offspring and resulting slow reproduction rates.

And yet, our birth spacing is relatively short. Galdikas and Wood (1990) studied a foraging group in Papua New Guinea and estimated that the birth spacing, if the previous child lived, averaged around 43 months . The birth spacing in gorillas was pretty similar, but chimpanzees needed more like five-and-a-half years, and orangutans almost eight years. With our longer lives, this translates into more potential children. In addition, agriculture shortened human birth spacing still more, not only because of the more consistent food source, but also because of sedentary life.

In other words, part of what made our ancestors an invasive ape, a colonizing species with a potential for demographic explosion, was the way our ancestors reproduced. Without this change to our fecundity, this extreme potential for fertility that we see so dramatically illustrated in Moulay Ismael and Mrs. Vassilyev, the effects of agriculture and later gains in hygiene and decreased mortality would not have been so great.

In fact, if anything, Moulay Ismael and Mrs. Vassilyev show us that human accomplishments in areas like improved nutrition, social cooperation, niche construction (including removing predators and decreasing infant mortality), and even political sophistication can affect the most fundamental biological forces of our evolutionary heritage: the capacity of our bodies to pass on our DNA.

As Kate Clancy warns, starting from anisogamy as the foundational fact of human mating predictably produces a skewed account of human reproduction, and it virtually assures that we will focus on male-female differences. Starting from Moulay Ismael can produce a warped sense of how human reproduction works, as Dorothy Einon (1998) also cautions. Oberzaucher and Grammer’s simulations are especially interesting to me because they highlight limits of any account that ignores numerous constraints on fertility, including male fertility. The reproductive process is complicated at a variety of levels, including the way that male and female fertility interact and how human awareness of ovulation (or lack of it) influence fecundity.

The ‘Long, Slow Sexual Revolution’ redux

A couple of years ago, I began arguing that one way to talk publicly about human reproduction and male-female differences from an evolutionary perspective, a way that avoided over-simplification, was to discuss how human reproduction became different from our ancestors’ patterns and from the other great apes. My goal is not to minimize male-female differences (after all, one cannot imagine a female Moulay Ismael). Rather, it is to draw the discussion of reproduction into the whole account of the emergence of human distinctiveness rather than let it remain anthropocentric and anachronistic, focusing only on humans in the present.

Too often, popular evolutionary psychology (the kind in news magazines and press releases) focuses exclusively on modern male-female differences, rather than the emergence of human distinctiveness. Don’t get me wrong; I’m not arguing that humans alone are exceptional. All apes reproduce in their own ways, and noticing this, and thinking about the comparisons, are key to understanding that human distinctiveness.

My argument, in short, is that humans evolved to be different from other apes, in part, because our ancestors mated, reproduced, and raised our offspring in ways that weren’t just different to other apes, but liable to be affected by our increasing cognitive, social, technological, and perceptual abilities. Sex unifies us with other living things, sure, but the way that we do it is distinctly human, in ways that are crucial for making us what we are today. We are able to change the manner in which we reproduce, both intentionally and unintentionally, boosting our fertility.

I proposed that, as shorthand, to short circuit the ‘Men-Are-From-Mars-Women-Are-From-Venus’ default setting when talking about sex, we discuss instead the ‘Long, Slow Sexual Revolution.’ The ‘Long, Slow Sexual Revolution’ is a multiple-million-year-long process that eventually leads to explosive reproductive success, unlike other apes, because it produced fecundity, or untapped potential for high rates of reproduction. When the conditions were right, our ancestors learned to offload some of the cost of reproduction from mothers to others. This untapped potential for fertility increased the pay-off for cooperation, technology, new foraging techniques and other human breakthroughs; all of these offered our ancestors direct gains, but also could boost their fertility.

If this sounds like an echo of Sarah Blaffer Hrdy’s (2009) work on alloparenting and maternal strategic choice in reproduction, it is. Hrdy takes seriously that women, like men, make strategic choices in order to reproduce successfully, even if they don’t realize it. One of women’s key strategies is to recruit support for parenting to shorten the turnaround time to reproduce again. For me, only by bringing Trivers’ work together with Hrdy’s can we understand, not just the differences between men’s and women’s reproductive strategies, but also the enormous gap between humans and other apes.

Moulay Ismael tells us about the theoretical limits of male fertility, and about the differences between male and female reproductive possibilities. But more than that, he throws into high relief that human reproduction is not simply a mixing of eggs and sperm.

Part of what makes us human is that our capacity to reproduce hasn’t been frozen since we shared a common ancestor with chimpanzees or with other apes. Our forms of reproducing have evolved. too. And this slowly unfolding revolution in the way we have sex and make babies is part of what has allowed our species – not just Moulay Ismael – to reproduce and multiply so successfully.

Additional reading & videos

Carin Bondar, The Bird and The Bees Are Just the Beginning, TED (this talk is awesome – detachable penises, prehensile penises, giant penis simulations, armor-piercing penises, duck sex, penile clitorises, ‘guppy porn’ and the ‘Magnum PI hypothesis’ — awesome, but scary).

Kate Clancy, Mate magnet madness: when the range of possible explanations exceeds your own hypothesis, Context and Variation (Scientific American blogs) — it’s from 2011, but I still think it’s worth re-reading.

Patrick Clarkin, Part 4. Humans are (Blank) -ogamous: Promiscuity & Physiology, Patrick F. Clarkin, PhD (blog).
____. Part 15 of the series (the most recent instalment) is here: Part 15: Humans Are (Blank)-ogamous: Lessons from Models of Sex and Love.

Jerry Coyne, The most children produced by human females versus males, Why Evolution is True.

Greg Downey, The long, slow sexual revolution (part 1) with nsfw video, PLOS Neuroanthropology.
_____. Becoming Human: How Evolution Made Us. Encultured Press (free book!): Apple iBookstore (for iPad) or Smashwords.

The Most Amazing Human Reproductive Records, Hub Pages.

References

Betzig L. (1992). Roman polygyny, Ethology and Sociobiology, 13 (5-6) 309-349. DOI: 10.1016/0162-3095(92)90008-R

Betzig, L. (1997). Introduction: People are animals. In Human Nature: A Critical Reader, pp. 1-17. New York: Oxford University Press.

Confer J.C., Easton J.A., Fleischman D.S., Goetz C.D., Lewis D.M.G., Perilloux C. & Buss D.M. (2010). Evolutionary psychology: Controversies, questions, prospects, and limitations., American Psychologist, 65 (2) 110-126. DOI: 10.1037/a0018413

Cooper T.G., Noonan E., von Eckardstein S., Auger J., Baker H.W.G., Behre H.M., Haugen T.B., Kruger T., Wang C. & Mbizvo M.T. & (2010). World Health Organization reference values for human semen characteristics, Human Reproduction Update, 16 (3) 231-245. DOI: 10.1093/humupd/dmp048

Davies A. P. C., & Shackelford, T. K. (2008). Two human natures: How men and women evolved different psychologies. In C. B. Crawford & D. Krebs (Eds.), Foundations of evolutionary psychology: Ideas, issues and applications (3rd ed.) (pp. 261-280) Mahwah, NJ: Lawrence Erlbaum Associates.

Einon D. (1998). How Many Children Can One Man Have?, Evolution and Human Behavior, 19 (6) 413-426. DOI: 10.1016/S1090-5138(98)00026-9

Freund M. (1963). Effect of frequency of emission on semen output and an estimate of daily sperm production in man, Reproduction, 6 (2) 269-286. DOI: 10.1530/jrf.0.0060269

Gould R.G. (2000). How many children could Moulay Ismail have had?, Evolution and Human Behavior, 21 (4) 295-296. DOI: 10.1016/S1090-5138(00)00043-X

Hrdy S. (2009). Mothers and Others: The Evolutionary Origins of Mutual Understanding. Cambridge, MA: Harvard University Press.

Oberzaucher E., Grammer K. & Szolnoki A. (2014). The Case of Moulay Ismael – Fact or Fancy?, PLoS ONE, 9 (2) e85292. DOI: 10.1371/journal.pone.0085292.s001

Oldereid N.B., Gordeladze J.O., Kirkhus B. & Purvis K. (1984). Human sperm characteristics during frequent ejaculation, Reproduction, 71 (1) 135-140. DOI: 10.1530/jrf.0.0710135

Ryan C., & Jethá C. 2010. Sex at Dawn: The Prehistoric Origins of Modern Sexuality. Harper.

Shackelford T. & Goetz A. (2009). Sexual conflict in humans: evolutionary consequences of asymmetric parental investment and paternity uncertainty, Animal Biology, 59 (4) 449-456. DOI: 10.1163/157075509X12499949744342

Togashi T. & Cox P. A. eds. (2011). The Evolution of Anisogamy: A Fundamental Phenomenon Underlying Sexual Selection. Cambridge University Press.

Trivers R. L. (1972). Parental investment and sexual selection. In B. Campbell (Ed.), Sexual selection and the descent of man, 1871-1971 (pp. 136–179). Chicago, IL: Aldine. ISBN 0-435-62157-2.

Valsa J., Skandhan K.P., Gusani P.H., Sahab Khan P. & Amith S. (2013). Quality of 4-hourly ejaculates – levels of calcium and magnesium, Andrologia, 45 (1) 10-17. DOI: 10.1111/j.1439-0272.2012.01301.x

Woods D.C., Telfer E.E., Tilly J.L. & Barsh G.S. (2012). Oocyte Family Trees: Old Branches or New Stems?, PLoS Genetics, 8 (7) e1002848. DOI: 10.1371/journal.pgen.1002848.g001

Originally published at:
https://web.archive.org/web/20180528203201/http://blogs.plos.org/neuroanthropology/2014/04/05/man-1000-children-limit-male-fertility/

(I am republishing a lot of ‘legacy content’ from our PLOS Neuroanthropology weblog, which has been taken down, along with many of the other founding PLOS Blogs. Some of these, I am putting up because I teach with them. If you have any requests, don’t hesitate to email me at: greg.downey @ mq (dot) edu (dot) au. I suspect many of the links in this piece will be broken, but I will endeavour to try to slowly rebuild this content. I originally published this on 10 January 2012. I have also included at the end some of the most substantial comments from the comment thread.)

A while back, Bora Zivkovic directed me (well, …all his Facebook followers) to the word, ‘sapiosexuality’: the tendency to become ‘attracted to or aroused by intelligence and its use’(thanks, Bora!).

Ironically, although the term may be a bit of a joke, the idea that intelligence is a species-specific aphrodisiac has more than a shred of evolutionary plausibility. Moreover, ‘sapiosexuality’ is a crucial point of reference in the contemporary discussion of human sexual selection, especially to break the stranglehold that Victorian social mores and sexist assumptions have on popular understandings of human sexual evolution.

I was reminded of the term ‘sapiosexuality’ after teaching my annual introductory course on human evolution. Student evaluations are in, and over and over again, student comments lead me to think that, in order to change popular understandings of evolution, we need not simply better data, but also better stories. Especially when tired, old tropes are repeatedly trotted out again in a popular discussion of how ‘evolution’ has shaped ‘human nature,’ even when the data is showing the opposite, we should wonder if evidence alone can ever overturn rusted on bad interpretations.

Jason Antrosio makes a similar point about the need for new metaphors in his post, The Tangled Bank: Old metaphors for new evolutionary understandings. I believe Jason is right. Pernicious evolutionary narratives cannot be displaced by facts alone: to replace a story, you need a competing story. Specifically, in this series of columns, I’ll discuss a contender that might displace the man-the-promiscuous-horny-hunter/woman-the-choosy-chaste-gatherer chestnut (if for no other reason, to try to head off too many more Ed Rybicki short ‘comedy’ pieces like ‘Womanspace’).

I believe that a story we might title, ‘the long, slow sexual revolution,’ does a better job of foregrounding the most important salient facts about human sexual selection and evolution. The opportunity I’m taking to discuss this alternative narrative is a documentary series that you can watch most of online where I got to try out this framing, and it seemed to work (as it also worked in my evolution class).

The video, with a caution before you watch

Australian network SBS aired ‘Sex: An Unnatural History’ over the course of six weeks.  I offered commentary in episodes one (below), five and six. (I can’t find episode 6 online.) The head researcher for the series read some of my earlier posts criticizing some forms of evolutionary psychology (the old posts are compiled here), and brought me on board, primarily to talk about evolutionary psychology and sexuality from a neuroanthropological perspective.

However, before you watch Episode One, ‘Revolution,’ a warning: the video is NSFW unless you work at a lad magazine, in a topless donut shop or in a similarly liberal environment. Australian television, especially SBS at 10pm on Friday night, is a LOT less tame than US TV (although nothing to rival Italy, I’m told).  Be ready for an eyefull of frontal nudity, simulated sexual intercourse, and even archival videos of ‘love ins’ of shaggy people from the 1960s — of course, that might be precisely the reason some of you showed up here (if so, talk about your low percentage surfing…).

At about 20:02 my voiceover makes its first appearance, accompanying footage of animals mating, straight and gay couples in flagrante, and some great shots of our farm, including a cameo by one of our horses who, ironically, is a gelding as well as a camera hog.

The series editors actually gave me the sort of ‘last word’ for the opening episode on sexual ‘revolution’, and I got to meet Julia Zemiro, Australian celebrity, actress, comedian, and Eurovision presenter, so I’m pretty happy about how it turned out.  And don’t worry: at no time do I appear naked!  Here’s the vid, and below the fold is the discussion…

The new story, in a nutshell

This post will stretch over at least three installments, so the punchline has to come early or you all might turn on me; besides, you might have something better to do. When asked about the ‘sexual revolution,’ and whether ‘the pill changed everything,’ at the end of episode one for the SBS series, I tried to shift the frame: the ‘big news’ in human sexuality as a species isn’t a revolution in a long-unchanged sexual rut that started with oral contraception (never mind that it’s parochial to assume that Euro-American middle-class trends define ‘human evolution’ or ‘human sexuality’ as a whole).

The 60s and 70s, including the ‘Sexual Revolution,’ feminism, divorce, and more and more diverse family structures, should instead be seen as a recent round of a longer-running, ongoing pattern of sexual change, a trajectory very different from those taken by our nearest great ape cousins: chimpanzees, bonobos, gorillas, and orangutans. They’ve had their own trajectories of sexual change over the same time, but we’re mostly concerned about our own.

Becoming human over the last five million years has included sexual changes almost as monumental as transformations to other aspects of our bodies, cognitive abilities, tool use, and social life. This sexual change has made use of some of the same resources and adaptive tendencies, and been instrumental in facilitating these other changes. Overall, the pattern of human sexual evolution has moved toward:

1. fluctuating and variable male-female equality and roles (with much less marked increase in dimorphism than gorillas or chimpanzees if we look across all traits and just don’t pick our favourites—I’ll come back to this in part 2 of the series);
2. exaptation and redeployment of sex for non-reproductive or semi-reproductive purposes (like cementing cooperation);
3. satisfying the broad demands of reproduction in our species, not just conception, but also parenting, provisioning and socialization;
4. adaptation of sexuality to balance the other needs of our species, such as foraging behaviour, hierarchy and social solidarity;
5. greater awareness of our own sexuality and corresponding top-down cognitive influences on sexual expression; and
6. in summary, a flexible, even contradictory sexuality, which, although it confounds the simple description of human sexual ‘nature’, is actually an adaptive strategy given an animal that is going to have to adapt quickly and respond sensitively to shifting contexts (such as a large-bodied, hyper-invasive, wide-ranging mammalian omnivore).

The idea of the ‘long, slow sexual revolution,’ I think, provides a simple and balanced umbrella for pulling together contradictory elements of our sexuality, gender relations, and reproductive strategies. Everyone knows that the more recent ‘Sexual Revolution’ didn’t erase pre-existing sexual mores and patterns, but rather mixed with them, producing a conflicted, sometimes-unpredictable pattern of sexual expression. Starting with a ‘sexual revolution’ rather than the Men-are-from-Mars-Women-are-from-Venus story means less erroneous leaping to stereotypes to undo when we teach or communicate about human evolution.

This idea that we have an inherently contradictory sexuality, the sixth point, is important because a one-sided narrative (say, for example, an argument that humans are ‘naturally’ bonobo-like, polyamorous and peaceful) shouldn’t be simply pitted against a pre-existing, opposing one-sided account, like the Mars-Venus contrast. I’ll come back to this point in part three of this series, but my fear of the over-corrective is the reason that I’m a touch uncomfortable with Ryan and Jethá’s (2010) book, Sex at Dawn. Although many of their innovative ideas are well worth considering, if for no other reasons to cleverly counter-balance other pervasive accounts of human sexuality in evolution, the book does run the danger of a competing partiality, however important the corrective may be.

The statistical prevalence of institutions like male dominance, female-centred family structure, and widespread idealization of monogamy (even alongside equally-widespread patterns of extra-pair mating and other forms of sexuality) is incontrovertible. Our discussion of sexual evolution has to be consistent with observable facts, both now and in our phylogenetic past, and we can’t be cherry-picking data to fit a feminist Darwinist or bonobo-ist polyamorous account any more than to fit an anti-feminist one.

Different proclivities in a species need not be harmonized by natural and sexual selection, nor need sexual selection be one-directional; the presence of unresolved conflicts in instincts or behavioural tendencies can produce a more flexible and responsive behavioural repertoire and a two-way form of social selection is likely in a highly intelligent primate. (Of course, unresolved tendency can also produce confusion and ambivalence, but that’s for part three). For example, a tendency toward male domination underwritten by sexual dimorphism and high levels of male aggression can be pitted against tendencies towards greater egalitarian sexual relations grounded in female sibling solidarity, female mate choice, and foraging versatility. Together, opposing tendencies can produce a behavioural repertoire that tips in quite different directions given the right conditions.

The caveat emptor: Although I’ve been spending a lot of my time in the last few years teaching and writing about evolution, it’s not my area of research, so all of this is based in my reading of the literature, much of which I do for teaching. Soon, I’ll be back to posting on my own research area as there’s much new stuff to report there, especially with the start of the rugby project.

What does the new narrative accomplish?

The narrative is hardly ‘revolutionary’ itself, but I think it accomplishes some important functions. Although I had lectured along these lines, calling this particular view the ‘long, slow sexual revolution’ for the SBS interview crystallized for me this counter to the presentist assumption that oral contraceptives ‘changed everything’ about human sexuality a few decades ago (the SBS researcher really liked this change and probably recruited me because of it). More importantly, as I thought about it, the ‘long, slow revolution’ framing also undermined the idea that sex—alone among human traits—was frozen and unmoved throughout evolution, as so much else of what makes us human underwent radical change and innovation.

First, some of the discussion around the documentary assumed that oral contraception unleashed ‘natural’ sexuality from being tied to reproduction; that desire and reproduction, prior to that point, were yoked together inseparably as heterosexist partners assuring the survival of our species. The ‘pill-causes-sexual-revolution’ argument underestimates, in my opinion, the degree to which sexual expression in humans (and in most sexual species) has long been much broader than just to get gametes together successfully. Sexual behaviours like mounting and receptive postures are routinely used to mark dominance, affiliation, and submission in many, if not most mammals (and sometimes even for dominance in reptiles and insects), and things get even more complex in humans, especially with concealed female fertility.

Among humans, we have known about and sought to manage fertility, sometimes with marked success, for millennia. The pill improved that control and the efficacy of techniques, certainly, but hardly represented an entirely unprecedented ‘revolution.’ So the idea that reproduction was a chain tying down sexual expressivity probably over-estimates the degree to which risk of pregnancy affected human sexuality (says this Catholic boy from a small family). Moreover, the ‘sexual revolution’ hardly meant that individuals’ desires were all suddenly acceptable and expressible.

Second, some of the discussion of the ‘sexual revolution’ of the 1960s and 1970s revealed a startlingly superficial awareness of variation in human sexuality across broader historical, archaeological and evolutionary scales, and of the complexity of sexual relations in different classes and social groups. Yes, the Sixties were a revolution compared to the force-fed sexual ideology of the post-WWII era, but the bourgeois marketer-manufactured idea of the perfect family of the 1950s was itself innovative, a willful distortion of actual patterns of reproduction, cohabitation and family structure in the period. And most families failed to live up to the ‘ideal’ in a host of ways—social, economic and reproductive—in the 1950s, long before they got all ‘revolutionary.’

Along these lines, the long, slow sexual revolution specifically undermines the amnesia and class-centrism inherent in the way some self-proclaimed ‘conservative’ political programs insist that they just fight for what is ‘normal’ or ‘natural,’ for example, against feminism or sexual rights movements. James Peron points out in the Huffinginton Post in ‘Creationism and the Marriage Debate,’that a kind of ‘faith-based’ history denies marriage was anything other than Ozzie and Harriet, in blatant contradiction even to the relationships described in the ‘sacred’ texts for these movements (yes, I’m talking about the Bible):

The moment someone tells me “marriage has always been” something or another, I know they are ignorant of the actual history of marriage. It has never “always” been anything. It has taken different forms, with different social rules attached. Those forms and rules changed as the function of marriage changed.

Third, the long, slow revolution narrative fights the tendency to argue that, in relation to sex, ‘human nature’ is what you get when you remove every human trait, as Daniel Lende and I have argued in a forthcoming book chapter. Anyone who argued that you get to the ‘nature’ of human cognitive ability in a thought experiment in which you strip off everything that’s distinctly human, like language, social complexity, and self-awareness, would be mocked mercilessly as a fool. And yet people can routinely assert that, when it comes to sex, we’re just follicley-challenged monkeys. (Greg Laden’s 2008 column on the subject specifically demolishes the idea that other primates offer some clear model for ‘natural’ sexuality. If you haven’t read it, the piece is still well worth the time.)

Finally, related to this last point, the ‘long, slow sexual revolution’ narrative more clearly locates sex with other dimensions of human existence in the account of our evolution, as both survival problem and resource. Sex isn’t just a trait, or a challenge, or a tool—it’s all of these at once. And the same dynamics that shape our other traits also affect our sexuality, including some very peculiar human dynamics, such as increasingly byzantine neural architecture and the ability to suppress even the most basic instinctual or reflex behaviour, deflect primary drives, and affect our own development into sexual beings.

The reason I push the ‘sexual revolution’ line is that I think this account makes intuitive sense to a broad audience, and that, as the layers of depth and complexity are added to the narrative, the foundation is essentially sound. Unlike other simple ways of talking about evolution (like the ‘selfish gene’ model, or the ‘we’re just bonobos in clothing’ story, in my opinion), you don’t wind up with people getting really, really off track by following logically on the implications of your beachhead narrative.

Some people might say that we don’t need a simple story to tell about the evolution of human sexuality, that we should ‘complexify’ and ‘problematize’ other accounts instead, refusing to be pinned down to something overly basic. I think that the ‘complexifying-problematizing’ rhetorical strategy is too distracting and diluted to oppose pernicious popular evolutionary fables. And the old, sexist narratives aren’t going anywhere without a struggle.

Old stories don’t die easy

One problem with old sex stereotypes in evolutionary narratives is that they are so damned clear and memorable. They’re hard to keep down because they appeal to our cultural common sense, so we have to seek to replace them with equally plausible, persuasive, and—to be honest—glib ways of describing alternative positions.

In the battle to persuade, good ideas also need sharp marketing: quick, clear ways to communicate the nub of an argument (as I’ve argued about ‘branding’ anthropology and Jason Antrosio is pointing out in his discussion of new metaphors). Those of us who seek to dislodge sexist narratives from evolutionary theory need both data and the same kind of forceful rhetorical tropes that old school sexist evolution accounts had; you know the type, the Men-are-from-Mars, Women-are-from-Venus version of human sexuality.

‘Dear Jesse, do you mind serving as an example?’

Case in point is a recent post on the Scientific American weblog, Bering in Mind, “Dear Jesse, I like very young girls.” In the post, self-proclaimed evolutionary psychologist Jesse Bering acts as an agony aunt, answering readers’ letters with evolution-based advice. Specifically, Bering writes to a self-declared ‘deep-thinking hebephile,’ an adult man attracted to pubescent-aged girls, that these predilections are not particularly rare and that society’s negative reaction is a case of it catching ‘an especially alarming sight of itself in the mirror.’ His answer, however startling, is a pretty logical extension of the typical, May-December evolutionary psychology account of human mate preference, that doods dig young chiks because it’s a ‘successful’ reproductive strategy.

Although Bering expresses some reservations, his reaction overall suggests that a hebephilic orientation would have been ‘biologically adaptive in the ancestral past.’ Moreover, Bering thinks that society might be over-reacting by forbidding adult-adolescent consensual relationships because some evidence might be interpreted to say that these relationships actually are all that detrimental to young people. (See Anna North’s argument with this last assertion at Jezebel.)

The reaction to Bering has been pretty deservedly scathing, as I’m leaving out some of the worst details. Isis the Scientist in An Open Letter to Jesse Bering takes Bering to task for his disregard for power, manipulation of children and feminism (Bering specifically suggests elsewhere he is sympathetic to ‘anti-feminism’). White Coat Underground argues that Scientific American effectively condones what Bering is writing. Stephanie Zvan at Almost Diamonds writes a response to the letter that is grounded in psychological and therapeutic practice, rather than in ‘evolutionary theory.’

Finally, Janet D. Stemwedel, at the science and ethics blog Doing Good Science, countered Bering specifically on the distinction between scientific explanation and moral justification: Science and ethics shouldn’t be muddled (or, advice for Jesse Bering). And, if you haven’t had enough, Chris Clarke provides a brilliant parody, Dear Jesse: I Want To Eat My Stepchildren. Is This Normal? and Jeremy Yoder a bit of a review of his own gripes with Bering.

…nevermind, we’ve got plenty of examples…

I’m not going to specifically delve into the Bering-hebephile controversy, or his less-commented-upon responses to other letters, equally grounded in the standard May-December mate preference model, which include an assertion that a 29-year-old woman is a ‘young, reproductively viable female with diminishing mate value in the throes of intense intrasexual competition with potential rivals for a desirable mate.’ (Kate Clancy has pointed out on Twitter how problematic his answers are; or see her response to Bering here).

The reason I won’t discuss Berring extensively is that, if I were to wait two more weeks to publish this post (and at the rate I’m going, I might), almost inevitably, another controversy—major or minor—would emerge from someone claiming that a particular strain of ‘evolutionary psychology’ justified trafficking in hackneyed gender stereotypes or penning an apologia for patriarchal sexual mores.

If I had written this post earlier (say, in November), I could just as easily have used the example of Ed Rybicki’s risible ‘comedy’ piece ‘Womanspace.’ If you’ve missed it, see Jacquelyn Gill’s comprehensive rundown of this sorry episode in science publishing at The Contemplative Mammoth. In fact, Rybicki’s story would have been an even better jumping off point than Bering’s column because Rybicki’s version of the sexist narrative was so, as Scicurious beautifully put it, tired and ‘smelling of old farts and cigar smoke.’ In other words, the Bering controversy just isn’t that interesting because it’s pretty predictable given the narrative problem dogging evolutionary accounts of human sexuality(Patrick Clarkin says as much in his blog, too).

Defending evolutionary psychology from the fables

When a piece like Bering’s, Rybicki’s, or Satoshi Kanazawa’s argument that black women are unattractive (pulled down by available here) is published and outrage ensues, also predictably, some other self identified ‘evolutionary psychologist’ comes along to disown the offense, pointing out that the offender is making the whole endeavor of evolutionary psychology look pretty bad, and probably isn’t really an evolutionary psychologist. The serious evolutionary psychologist will insist that the problem is neither evolutionary theory, nor psychology, but this particular individual’s interpretation of evolutionary psychology (for example, in this report of the refutation of Kanazawa at the Times Higher Education supplement and the letter (download pdf)). And I agree.

The problem of evolutionary psychology in the public sphere isn’t generally the research, or serious researchers and theorists (although I’m ambivalent about Bering and a couple of others who seem to revel in anti-feminism). The problem is the over-arching narrative available for anyone to pick upand wave around, selectively cherry-picking a little bit of data, an anecdote, or a cultural common sense point before going out for a little jag. I think serious evolutionary psychologists are a bit too cavalier about this narrative, knowing full well that it no longer represents the state of understanding in the field of evolutionary theory. They have a responsibility to counter the sexist, retrograde account of human sexuality if they don’t like being tarred by the brushes that come out to knock down amateur ‘ evolutionary psychology.’

The problem is that this terrible narrative inevitably tends to drag down any discussion of the evolution of sexuality into misogyny, gender stereotypes, and apologia for inequality, providing a thin pretense for an up-swelling of reactionary attitudes in non-scientists. As a man, I’m even offended by the portrayal of masculinity, the smug confidence that if I don’t recognize I’m a pig (who wants to sleep with adolescents or can’t figure out the most basic domestic tasks, in the case of Bering or Rybicki), I’m just denying my true masculine nature.

If I, like other cultural anthropologists, have to hose down overly radical cultural constructivists and take flack for some of their weirder pronouncements, then evolutionary psychologists have to do more to counter-act sexist rhetorical tropes.

The amateurs often use principles that haven’t been dominant in evolutionary theory since the 1960s; even basic textbooks in human evolution have caught up. But amateurs can and do traffic in the old stories because the foundational Mars-Venus narrative hasn’t been sufficiently put to rest, stake through the heart style. The particularly delicious irony is that the story even gets faithfully repeated when it appears at odds with or utterly unconnected to the more specific results of the research, as often is the case in science reporting (and I’ve discussed in some of my earlier posts on evolutionary psychology and sexuality). In other words, we need a strong narrative antidote to clichéd accounts of human evolution to short-circuit a popular communication problem.

Evolutionary psychology and feminism

The big problem for evolutionary psychology, which is not a feature of evolutionary thought more generally, is anti-feminism. As Laurette Liesen (2011:749) points out, evolutionary psychologyoften has been especially resistant to feminist intellectual critique and methodological corrective, whereas evolutionary biology has successfully integrated many key insights from feminist biologists (see also Liesen 1998, 2007). Cassidy (2007) has argued that feminism and evolutionary psychology have been pitted against each other since the 1970s, when evolutionary psychologists opposed the ‘women’s liberation’ movement, some of them (such as David Buss) specifically arguing that one could not be both a feminist and an evolutionary psychologist.

The relationship between evolutionary psychology and feminism probably hit its nadir with the publication of Randy Thornhill and Craig Palmer’s (2000) book, A Natural History of Rape: Biological Bases of Sexual Coercion. The book argued that rape was primarily a reproductive strategy, predating the emergence of our species, whereas feminists argued that rape was about power, an expression of patriarchy and an act of violence. In fact, Vandermassen (2010) argues that the evolutionary and feminist perspectives are compatible, but this stream of thinking in evolutionary psychology tended to drive feminist thinkers from evolutionary psychology even though their perspectives could really enrich the endeavour.

For example, primatologist Sarah Hrdy, in a long and distinguished career, has demonstrated how shifting the research and theoretical focus to strategies of females and infants provides a much more complex perspective on the diverse demands of reproduction and the selective pressures introduced by complex social lives (see esp. Hrdy 2009). In her book, Mother Nature (1999), for instance, Hrdy argues that the ‘maternal instinct’ is not an inevitable behaviour pattern; female primates assess the health and viability of infants, and can neglect those judged to be unlikely prospects. In addition, if possible, mothers may farm out infant care to ‘alloparents,’ often sisters, grandmothers, or the infant’s siblings. By recognizing that women are active in sexual reproduction in a range of ways, that mothers, too, make strategic decisions about mating and child rearing, we better understand complex primate social life.

At this stage, with work like Hrdy’s well known, it’s simply incontrovertible that feminist critique has made evolutionary theory better since the time of Darwin. It’s not just feminist biologists who have helped, obviously, but you’d have to be pretty recalcitrant to insist that work like Hrdy’s is not hugely important to our understandings of primate reproduction and sexual selection.

Feminism, of course, is a broad area of thought with blurred boundaries (as is ‘evolutionary psychology,’ in fact), in some areas philosophy or political project, in others practical, methodological and theoretical. One cannot write a simple definition of ‘feminism.’ Evolutionary psychologists tend to get hung up on the political project of feminism and believe that the foundation for their disagreement with feminist biologists is that the evolutionary psychologists are doing ‘science’ and their critics are practicing politics.

In some cases, the evolutionary psychologists are right: the critique is political. But that’s often because the psychologists themselves strayed over the line from ‘science’ into social, cultural or political interpretation. Either that, or they have a tin ear for how their arguments are going to be heard. That is, evolutionary psychologists often don’t get why they’re arguing with other intellectuals, or at least they act like that they don’t get it.

For example, when Buss and Malamuth (1996) sought to bring together feminism and evolutionary psychology over a decade ago, they were so concerned with the ‘naturalistic fallacy’—the conflation of scientific and ethical thinking, or ‘what is’ with ‘what ought to be’—that they spent most of their energy and ink trying to argue against political forms of feminism, failing to bring on board the insights of methodological and theoretical feminism in science. The effort by Buss and colleagues may have been genuine, but they were more concerned with their interlocutors’ failings than their own (at least, that’s how I read it). Likewise, evolutionary psychologist Robert Kurban’s response to those who criticize his field is four bits of advice, all of which are ‘learn more about evolutionary psychology.’

Even in more recent academic venues, evolutionary psychologists argue that their communication problem lies mostly in the reception; Kurzban (2010), for example, suggests that critics don’t engage their ideas ‘on scientific grounds,’ stymieing the entire production of knowledge:

Debate and discussion are, of course, all to the good. Conflict helps distill truth, as champions make their cases for their favored proposition, allowing their views to be judged by observers.

The challenge faced by evolutionary psychology, however, is that the critics do not participate in this dialectic. Interlocutors engaging with evolutionary psychologists frequently don’t engage with evolutionary psychology, preferring instead to fabricate evolutionary psychologists’ views, and then attack the imagined positions (see Kurzban, 2002).

Why is this the case? At this point it is unclear.

Kurzban’s critique is valid, of course, as many of the critics do miss the mark or offer political criticism instead of scientific rejoinder. But what he sees as the inaccurate aim of the critics is often a response people claiming to be ‘evolutionary psychologists’ themselves first wandering out of the protected game reserve of ‘science’ and into the wilds of politics, social criticism, or, even more dangerous, sexual advice columns.

As most any anthropologist or researcher in the social studies of science would hasten to say, it’s hard enough to do science without a political perspective sneaking in under the cloak of objectivity and value neutrality, let alone keeping ‘scientific’ when you’re writing sexual advice (which Kurzban is definitely notdoing). Especially in a field like evolutionary psychology, where, Kurzban points out, serious questions are being addressed with broad implications, the tightrope between what ‘is’ and what ‘ought to be’ is a challenge. You can’t avoid the tightrope simply by pretending you’re not walking it.

If Kurzban or other evolutionary psychologists are really mystified, or ‘unclear’ as Kurzban suggests, about why critics ‘are not just skeptical, they are angry’ (Kurzban quoting Daly and Wilson 2007: 396), or truly in the dark why their interlocutors appear ‘to be motivated by something other than a humble search for the truth’ (Kurzban quoting Daly and Wilson 2007: 390), I can help. Alas, if evolutionary psychologists feel ‘unfairly accused’ and ‘unjustly condemned’ (Kurzban 2002), I think I might be able to explain it: they’ve got a chronic, recurring narrative problem.

Not all publicity is good publicity

When critics attack evolutionary psychology, they typically don’t have to ‘fabricate evolutionary psychologists’ views.’ Instead, critics take popular or just out-dated versions of evolutionary psychologists’ arguments like those put forward by Bering, Rybicki or whatever scandaloteur du jour gets wide media play. If Kurzban really doesn’t understand the dim view taken of evolutionary psychology by feminists and others, he probably doesn’t realize how much damage this sort of publicity does to his field, both with other intellectuals and with the reading public. The misogynist pop evolutionary psychology also attracts those looking to justify their own retrograde attitudes (anyone who doesn’t know what I mean, just look in the comments on any blog post discussing research on sex differences in evolutionary psychology, perhaps even this one).

Perhaps because he doesn’t realize the damage being done, Kurzban’s excellent blog (Evolutionary Psychology, found here) tends to focus more on the ‘we’re misrepresented’ part of the ‘scientific dialectic,’ rather than on clarifying errors within the field or fighting misrepresentation of evolutionary theory by those who claim to represent it (a rare exception is his post about Kanazawa’s column on black women, but even there, Kurzban gets around to how unjust it is to treat evolutionary psychologists badly because of Kanazawa). Kurzban is pretty quick to point out when critiques of evolutionary psychology have failed to keep pace with changes in evolutionary theory (for example, on his weblog here and here), but a bit less swift to point out when erstwhile public proponents of evolutionary psychology are a decade or more behind, as well.

I have no doubt that Kurzban and other evolutionary psychologists feel misunderstood, even aggrieved. But if having a pitcher of water poured on another person’s head at a meeting in 1978 (as happened to E. O. Wilson) is enough to produce a sense that you and your field’s persecuted, you should be able to spare a bit of empathy for other oppressed groups. And if being told you’re not a ‘science’ offends or hurts, as Kurzban implies, then certainly he can spare some fellow-feeling for the feminist scientists so often on the receiving end of that particular rhetorical truncheon. I would hope that, if a bunch of smart evolutionary psychologists really put their minds to it, they could well understand why feminist intellectuals should feel persecuted by evolutionary psychologists if the psychologists are still retelling tales of aquatic insult at a conference more than thirty years old.

I agree with Kurzban on many issues, but if he and other evolutionary psychologists want to make some headway on their public reception problems, I doubt they’re going to make much progress by just complaining that they are misunderstood. In addition to opening themselves to legitimate critique by feminist evolutionary psychologists (which I think most do), they’ve also got to help with cleaning up the public narrative. It’s probably not efficient or a good use of their time for serious evolutionary psychologists to have to deal with each poseur, one at a time, writing blog posts again and again saying, ‘He claims to be one of us, but he’s just another misogynist. Go ahead with the online beatdown…’ Instead, they could attack the misleading and partial narrative, helping to replace it with a better one.

Ironically, as Richard Wright (1994; cited in Smith and Konick 2011: 597) has pointed out, some of the ‘evolutionary’ perspectives on men’s innate attitudes are remarkably similar to the most rare and radical anti-male brand of feminism — ‘Human males are by nature oppressive, possessive, flesh-obsessed pigs’ is how Wright put it — a delicious case of extremes doubling back to meet each other. It’s just that the supposed evolutionary theorists often don’t think there’s anything we can or should do about piggish behaviour. (Or, as Bering implies, society should probably just lighten up about men behaving badly because a few hundred generations ago, the behaviour would have been pretty normal and adaptive.)

It’s possible, however, as Kate Clancy points out, that some evolutionary psychologists may simply enjoy the role of ‘science provocateur.’ They might relish provoking public reaction or ginning up outrage by finding new ways to assert that feminists or other progressives are just soft-headed, self-deluding, politically-correct ninnies fighting human nature, like well-meaning nitwits raging against gravity for being oppressive.

If they’re just in the debate to have a bit of a lark, then my advice is pretty much moot (and if this is you, please don’t bother commenting as I won’t respond – I’ve got too much to write). But I think that there’s a possibility of strengthening the discussion of evolutionary psychology by expanding it significantly to include more paleoanthropologists, neurologists, anthropologists, primatologists, ethologists, historians, and, yes, anthropologists of all stripes.

One could find unhelpful strains of all these disciplines, of course, such as overly politicized scholars of various sorts who might be opposed on principle to the effort or scholars who only see things through their own disciplinary lenses and refuse to acknowledge the potential validity of any other approach. But a serious consideration of the relation between human evolution and sexual psychology would need to be pretty open and willing to listen to diverse perspectives, one would think. And a good starting point would be a change in the orienting narrative.

Where we’re going with this post, credits and predecessors

The ‘long, slow sexual revolution’ account of human sexuality is hardly original, as I’ve tried to make clear. It’s simply my way of trying to communicate in some coherent, simple package, diverse ideas that I’ve learned from people like evolutionary psychologists Robert Trivers and David Buss, sociobiologist E. O. Wilson, biologist Anne Fausto-Sterling, and anthropologists Don Symons, Meredith Small, Agustín Fuentes, Jonathan Marks, and Sarah B. Hrdy, among many others.

More immediately, this particular column has been influenced and inspired by fellow online writers Patrick Clarkin (check out his excellent series on human pair-bonding which starts here), John Hawks, Greg Laden (see especially his piece on female orgasm), Kate Clancy (I’ll talk about her post on ‘mate magnet madness’ more in the second part of this series), Eric Michael Johnson (see his great discussion of recent genetics research on polygyny) and Jeremy Yoder (amazing long read relating his own homosexuality to his interest in evolutionary theory and the possibility of a ‘gay gene’ persisting in a population).

What I hope to add in this series of post, however, that may not appear in some of the others discussions of the evolutionary psychology scandal-of-the-month, is an analysis of the story that underpins this interpretation and a proposal for an alternative story we can tell about human sexuality and evolution that is intellectually inclusive.

The next post will review the primary conceptual foundations of the kind of narrative that predictably produces material like Ed Rybicki’s story and Jesse Bering’s advice. I don’t think it’s just sexism that produces sexist evolutionary psychology, but an inordinate focus on a small number of key issues: anisogamy, sexual dimorphism, universalism, and ‘mate preference,’ predominant among them. My goal is not to argue that these factors are not important, or even to say that they might not produce something like the sorts of tendencies that the Mars-Venus account of human sexuality suggests, but rather to suggest that they might not be quite as clear cut or unchangeable as sometimes assumed.

The third post will offer my approach to teaching the ‘long, slow sexual evolution,’ maybe even my slides if I can pull it together, in a way that includes both long-standing concepts in discussions of human sexual selection (all the ones that I discuss in post two), as well as other material that I think works well with students and popular audiences. In particular, one way that we can teach human evolution and sexuality is to highlight how the ‘revolution’ produces contradictory elements in our sexuality, and that this instability is actually an adaptive resource, allowing human sexual behaviour to shift quite dramatically given different social and contextual pressures.

Additional reading

If you haven’t had it by this point, here’s some additional columns, including many discussed in the post.

• Jason Antrosio, Living Anthropologically, The Tangled Bank: Old metaphors for new evolutionary understandings).
• Kate Clancy, Context and Variation, Mate magnet madness: when the range of possible explanations exceeds your own hypothesis
• Patrick Clarkin, Patrick F. Clarkin, PhD, Part 1. Humans are (Blank) -ogamous
• John Hawks, John Hawks Weblog, The real “junk” DNA
• Eric Michael Johnson, The Primate Diaries, The Case of the Missing Polygamists
• Greg Laden, Greg Laden’s Blog, Coming to terms with the female orgasm
• Emily Willingham, The Biology Files, Women know something you don’t.
• Jeremy Yoder, guest post at Scientific American, The Intelligent Homosexual’s Guide to Natural Selection and Evolution, with a Key to Many Complicating Factors
• Ed Yong, Not Exactly Rocket Science, Control Altered by Deletion – is lost DNA behind our bigger brains and spineless penises?

References:

Buss, D., & Schmitt, D. (1993). Sexual Strategies Theory: An evolutionary perspective on human mating. Psychological Review, 100 (2), 204-232 DOI: 10.1037/0033-295X.100.2.204

Cassidy, A. (2007). The (sexual) politics of evolution: Popular controversy in the late 20th-century United Kingdom. History of Psychology, 10 (2), 199-226 DOI: 10.1037/1093-4510.10.2.199

Daly, M., and Wilson, M. (2007). Is the “Cinderella effect” controversial? A case study of evolution-minded research and critiques thereof. In Foundations of Evolutionary Psychology, C. Crawford and D. Krebs, eds. Pp. 383-400. Mahwah, NJ: Erlbaum.  (pdf available here)

Eagly, A., & Wood, W. (2011). Feminism and the Evolution of Sex Differences and Similarities Sex Roles, 64 (9-10), 758-767 DOI: 10.1007/s11199-011-9949-9

Hrdy, S. (1999). Mother Nature: A History of Mothers, Infants and Natural Selection. New York: Pantheon Books.

_____. (2009). Mothers and Others: The Evolutionary Origins of Mutual Understanding. Cambridge, MA: Harvard University Press.

Kurzban, R. (2010). Grand challenges of evolutionary psychology Frontiers in Psychology, 1 DOI: 10.3389/fpsyg.2010.00003

Liesen, L. (1998). Book reviews Evolutionary Anthropology: Issues, News, and Reviews, 7 (3), 105-113 DOI: 10.1002/(SICI)1520-6505(1998)7:33.0.CO;2-M

Liesen, L. (2007). Women, behavior, and evolution Politics and the Life Sciences, 26 (1), 51-70 DOI: 10.2990/21_1_51

Liesen, L. (2010). Feminists, Fear Not Evolutionary Theory, but Remain Very Cautious of Evolutionary Psychology Sex Roles, 64 (9-10), 748-750 DOI: 10.1007/s11199-010-9857-4

Ryan, C. & Jethá, C. (2010) Sex at Dawn: How We Mate, Why We Stray, and What It Means for Modern Relationships. Harper Perennial: New York.

Smith, C., & Konik, J. (2011). Feminism and Evolutionary Psychology: Allies, Adversaries, or Both? An Introduction to a Special Issue Sex Roles, 64 (9-10), 595-602 DOI: 10.1007/s11199-011-9985-5

Thornhill, R., & Palmer, C. T. (2000). A Natural History of Rape: Biological Bases of Sexual Coercion.Cambridge: MIT.

Vandermassen, G. (2010). Evolution and Rape: A Feminist Darwinian Perspective Sex Roles, 64 (9-10), 732-747 DOI: 10.1007/s11199-010-9895-y

Wright, R. (1994, November 28). Feminists, meet Mr. Darwin. The New Republic 34-38.

Selected comments

1. Well done Greg! Excellent overview and I am looking forward to the next segment!
   Let me just add my emphatic support to your strong points and fine prose via a super brief summary of the chapter on busting the myth of sex/gender differences in my upcoming book. This is the take home message based on an extensive survey of anthropological, biological and psychologicla literature on sex and gender differences:

   “There are important biological differences between the sexes and there are also important similarities, however there is a greater range of overlap in male and female bodies than most people realize. Behaviorally males and females also overlap extensively. Humans, regardless of sex, seek to form pair bonds of both social and sexual sorts, but pair bonds and marriage are not the same thing. Males and females, given the opportunity, will engage in sexual behavior across the lifespan in more or less the same rates and manners. These strong similarities in male and female bodies and behavior do not mean that gender differences are not real and important. Gender is a powerful cultural construct and the perception and expectation of gender differences impacts individuals and society. Males tend to control economic and political resources and women are heavily involved with the child rearing because they give birth and lactate, but males and females have the same behavioral ability to care for offspring. There is no biological or evolutionary mandate that only females care for young and only males care for economics and politics. These patterns of gender difference and the strength of the cultural assumptions about sex fool us into thinking that men and women are so different by nature.”

   1. We should make sure to cover your new book when it’s out, Agustín, here at Neuroanthropology. I saw the one-sentence summary when I linked to your profile — looks very good.

       

      1. I’ll make sure they send copies! This post is really good…have you thought about turning this set of musings into more than blog?

          

   2. This comment reminds me of something from the book Sex, Drugs, and Coco Puffs:

      “Apples and oranges aren’t the different, really. I mean, they’re both fruit. Their weight is extremely similar. They both contain acidic elements. They’re both roughly spherical. They serve the same social purpose. With the possible exception of a tangerine, I can’t think of anything more similar to an orange then an apple. If I was having lunch with a man who was eating an apple and- while I was looking away- he replaced that apple with an orange, I doubt I’d even notice. So how is this a metaphor for difference?…”

      It is very true that men and women are very similar to one another and one could posit a number of way in which the ways we struggle in our daily lives is similar to Chimps, ground squirrels, and pigeons (I am not, by analogy, claiming that men and women are as different as apples and oranges) . We can certainly learn things by looking at the similarities between things, but also the differences. You note differences above based on the “cultural construct of gender”. And it is true that culture has a strong influence on people, but people’s genetic pre-dispositions do also. Both culture and gene’s are not immutable forces as you note… but why is it wrong if some researchers want to focus on understanding the non-immutable genetic predispositions that might lead one to be misogynistic rather than the cultural one’s that have the same effect. I assure you, real change will not be possible without understanding both elements of the equation–indeed men and women have very different psychologies based on a different selective history and different ontogenetic developments. Pretending the former does not exist or is unimportant in order to make changes in the ladder will fail. So are men and women different by nature? If you mean that they must always and in every case and environment be different than… duh no. If you mean that men and women have different behavioral proclivities based on differential success of certain strategies which are contingent on the environment providing certain regularities then… duh yes.

       

2. Great interview, Greg. I think “sex is like hands” should become an internet meme. I don’t know if I can forgive you for “koala bears” though — sheesh, call yourself a new Australian?!

    

3. Wonderful, Greg! I’m looking forward to the next installments in the series.

    

4. This was a fantastic read, and I’m also looking forward to the next installments. I’m bookmarking this one.

    

5. Pingback: Roundup (Jan 10, 2012) « Patrick F. Clarkin, Ph.D.

6. A really wonderful post Greg. I particularly appreciated your understanding that changing the discussion about the evolution of human sexuality will require a dual-pronged approach that involves both evidence and storytelling. So many of the evolutionary stories that are stuck in people’s heads were ones developed prior to 1970 and have had forty years to weave their way into popular consciousness through comics, books, and movies. There is a lot of cultural reinforcement behind these flawed narratives that evidence alone will not displace. I’ll be looking forward to the next part in this series and appreciate all of the time you put into this analysis.

   1. Thanks, Eric. Your piece on the ‘missing polygamy’ was an immediate inspiration to try to tell stories and not just give the facts. Your own work features heavily in the next couple of posts in this series — I think you’re doing a lot of the same sort of thing: trying to dislodge this hard-to-remove master narrative. Coming from such a good writer, it’s quite a compliment.

7. I’m rather surprised at myself that I at least skimmed over this entire post since I fall directly into the category you described of interested intellectual women who have tossed the entire topic into a garbage can because it never seems to be comprised of anything but a herd of hooting middle-aged male degenerates trying to convince me that rape is just good fun while their ravening 20-something acolytes cheer.

   Not to say that you’ve convinced me to avoid the topic, either. But it’s a very nice, very exhaustive rundown of the issues and should be helpful for those people who haven’t gotten entirely sickened by it yet. 😛

8. Excellent piece. I enjoyed your nuanced approach to these oft-oversimplified issues. (Yes, I’m aware of the irony…)

9. Pingback: The Edge.org Annual Question: Beautiful Explanations | Evolutionary Psychology
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14. Interesting post. On the whole it seems very reasonable and balanced, but I do have one (rather pedantic!) issue to bring up: your description of Jesse Bering as a “self-proclaimed evolutionary pyschologist”. This does seem to imply that there is some sort of official qualification process for being an evolutionary psychologist, and that those who don’t have it are merely self-proclaimed. Jesse is an academic psychologist – with a PhD in developmental psychology – who happens to believe strongly that evolutionary theory can help us understand the human mind. Doesn’t that make him as much an evolutionary psychologist as anyone?
    In the context of your discussion of hebephily, you might also want to make clear that Jesse is openly gay – so it is not a case of his unconscious desires motivating his arguments!
    (Disclosure: Jesse was my PhD supervisor.)
    Other than those quibbles, I enjoyed the post and I do think these issues need to be discussed calmly and rationally, as you do here.

    1. Hi Gordon —
       Glad you thought the piece was (at least close to) balanced. I didn’t mean ‘self proclaimed’ as a dig — I always think ‘so called’ sounds that way. I just meant that *I* wasn’t the one saying Bering was an ‘evolutionary psychologist’; he did.

       Sorry part 2 is taking so long, but I’ve got a couple of article deadlines I’m up against, and they’re kicking my butt.

15. Thanks for your reply, Greg … you know, I kind of realised as soon I hit “Post Comment” that you weren’t being derogatory but had meant that he was acknowledging the label for himself, and then realised I had wasted my time writing the comment. So often the way 🙁
    Good luck with your article deadlines, and I look forward to Part 2!

16. Pingback: Salvando a Darwin de la Cosmopolitan | Juan Buridan
17. Pingback: Salvando a Darwin de la Cosmopolitan « antropoLOGIKA
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19. Pingback: Part 6. Humans are (Blank) -ogamous: Many Intimate Relationships « Patrick F. Clarkin, Ph.D.

20. I loved this when you posted it last year. I’m sure you’ve plenty else occupying your time, but what are the prospects for seeing parts 2 and 3 any time soon?

(I [Greg] am republishing a lot of ‘legacy content’ from our PLOS Neuroanthropology weblog, which has been taken down, along with many of the other founding PLOS Blogs. Some of these, I am putting up because I teach with them. If you have any requests, don’t hesitate to email me at: greg (dot) downey @ mq (dot) edu (dot) au. I suspect many of the links in this piece will be broken, but I will endeavour to try to slowly rebuild this content. Daniel originally published 7 December 2012.)

I just dropped my two young children at elementary school. They were bright and smiling, one off to practice handbells for a Christmas concert, another to chat with friends before the first bell.

Neither noticed the police car newly parked beside the school. Neither had a penny for my thoughts, of what it must have been like for those parents in Newtown, dropping off beloved children and then not having them only a few minutes later.

Now at my computer, I think of the Connecticut State Police Spokesman Lt. J. Paul Vance, the man who has guided us through much of this tragedy. I remember his assurance on Friday that the police were doing everything to find out not only what happened, but why.

But why.

No Easy Answers

With violence, there are no easy answers, as I wrote about in my summer piece Inside the Minds of Mass Killers after the Aurora Batman shootings.

One narrative – that Adam Lanza was mentally ill – is already waiting in the wings, prepped as an explanation. Another – where guns are the culprit – has exploded already with full force. Lanza used a semi-automatic assault rifle with extended clips and shot his victims multiple times. He had hundreds of more rounds to continue his killing. Without that firepower, he couldn’t have killed so many so quickly before taking his own life when the police arrived.

The United States urgently needs more and better mental health care. Regulating guns like we regulate motor vehicles seems reasonable, given how many thousands die from gun shots and from car accidents every year. Neither, though, gets us much closer to why.

Mentally ill patients are not more violent than anyone else. Guns don’t shoot themselves.

We still need better answers. The horrendous violation that Lanza committed, against all social norms, against everything that is decent and good, stares back at us with such dark eyes.

On “Adam Lanza’s Mother”

Thinking the Unthinkable, where the mother of a violent 13 year old recounts her own struggles with her son, swamped social media over the weekend. A truly viral post.

I live with a son who is mentally ill. I love my son. But he terrifies me.

Liza Long, aka Anarchist Soccer Mom, found much support with her post. Her call for more attention to mental health issues resonated broadly. But in being so public about her son, and linking violence and mental health so closely, Long also opened herself to considerable criticism – You Are Not Adam Lanza’s Mother and Want the Truth Behind “I Am Adam Lanza’s Mother”? Read Her Blog are two of the most prominent.

Long’s effective writing, evocative story, and sense of timing help explain how her post got circulated through so many Facebook pages. But she does one other thing that makes a huge difference. She speaks of how violence terrifies, and how little she can understand it. Yet there is her son, in the throes of fury and lashing out.

A few weeks ago, Michael pulled a knife and threatened to kill me and then himself after I asked him to return his overdue library books. His 7 and 9 year old siblings knew the safety plan—they ran to the car and locked the doors before I even asked them to. I managed to get the knife from Michael, then methodically collected all the sharp objects in the house into a single Tupperware container that now travels with me.

How to make sense of that? Pulling a knife over library books?!

Fitting Categories

Through her own experience, Long helps us catch a glimpse of the violence of being human, and to sense, at a distance, how quickly it can destroy life. For me, that is why the piece resonated. Newtown scares us deeply, the idea that someone can do such a thing. Yet Lanza did.

Soccer Mom Long also presages our societal response – fearful, distancing from the problem, controlling the pointy objects, and making it mental alone. And for me, that is deeply problematic. It fits violence into the wrong category, making it some natural object that we then try to control socially.

Don’t get me wrong. I think improvements in policing, gun control, and mental health care are all needed to help further reduce violence in our society. We need a multi-dimensional approach for a multi-dimensional problem.

But we also need better answers to the question Lt. Paul Vance posed for us, and so many have asked ourselves since Friday – Why?

Seeing Violence

Most of us hide our eyes from violence until some horrific event like the murders in Newtown force such things before our eyes. One of the braver things Obama did in his Friday press conference was to at least mention other massacres that haven’t caught the public’s attention so much – the murder spree in Chicago (over 400 this year) and the killing of six at a Sikh temple by a white supremacist.

One might cast a broader eye, and include the truly horrific number of murders in Mexico due to the drug war or the children killed by US drones abroad. Or to the past, and the killings of juveniles at the Dozier School in Florida. But black youth, religious minorities, foreigners, children of terrorists, and delinquents do not evoke the same sympathy. They do not force us to look longer. They should.

We also might look closer at the violence of our art and entertainment, and not just our gun culture. David Dobbs wrote about the Aurora shootings, Batman Movies Don’t Kill, But They’re Friendly to the Concept.

The movies are a enormous, constant, heavily influential part of an American culture that fetishizes violence and glamorizes, to the point of ten-year wars, a militarized, let-it-rain approach to conflict resolution… Culture shapes the expression of behavioral traits. The traits don’t rise inherent as an urge to play basketball or a plan to shoot up a Batman movie. A long conversation between the trait and the surrounding culture shape those expressions. Culture gives the impulse form and direction.

My wife, when she studied justified versus unjustified violence, found that justified violence – such as to save someone or even at times revenge – led people to approve more violence than violence that was deem unjustifiable. James Bond’s violence is legitimate, even thrilling.

We forget one thing about how culture works, something pointed out by Victor Turner and Claude Levi-Strauss many years ago – that symbols and meanings often work through dualities and oppositions. I still remember my street kid friend in Bogotá describing his life, that just like the morning sun comes over the city and the good people come out, so too the dark sun comes up at night and the dark people come out. And how they hated at times the people of the day, with their good lives and comfortable justifications and easy condemnations.

Our violent heroes don’t turn the other cheek. They go out and punish, often with multiple gun shots, those who are against them. Is it so hard to understand that our anti-heroes do the same?

Of Right Mind

Lanza killed little kids. Innocents most white and wide-eyed. I have called attention before to “running amok,” a cultural model and interpretation of violence, as one way to try to grasp how someone could engage in such horrid behavior. But one word that has stuck with me this time is “deranged.”

Someone in their right mind does not go out and kill kids. That is our sense of things, despite the regular news of parents who abuse and kill the children in their care. But they don’t then go and kill their neighbor’s kids.

Why “deranged”? I suppose because I find it hard to accept that someone like Adam Lanza was in their right mind. That even if there are cultural meanings he can draw upon, he still went and did it himself. And that I find comfort in thinking something inside his brain didn’t work the same way that things work inside my brain.

But I don’t mean mentally ill. Not at all. I mean violent. Violent in the most transgressive of ways. Violent in the most deliberate of ways.

If we’re going to think of violence as a sickness, then it is its own type of sickness, different in kind and in expression from the mental and physical ailments that also possess us. Violence is red in tooth and claw, seemingly primordial, until we recognize how socially regulated it is. We teach soldiers in violence, and then punish when they step outside the rules of engagement.

Violence relies on the tools at hand, on fists and knives and guns and planes, tools that we create and control. Violence has targets, often dehumanized, the japs or commies or crips on the other side, a fiction we can maintain until it is so roughly violated by something like Newtown. And violence works terror, that the overwhelming brutality of it will keep the other at bay and that we ourselves won’t be touched. But violence boils beyond the easy boundaries we try to place on it, and we are left once again in a land of no easy answers.

Policy

Teaching, tools, targets, and terror – that’s as close as I will get to a framework today. But I don’t want to end just yet. There remains the question of what to do.

President Obama has called for meaningful action. In government, meaningful action is often symbolic, done in speeches and codified into law. Gun control would at the very least signal that things have shifted, that we will not accept this type of violence, that we are willing to place limits on our freedom for the collective good of our children.

It is increasingly clear that the quick response time of police helped save lives in Newtown. We have gotten extremely good at rapid response. We are still very bad at how to deal with violence before or after that urgent moment.

We need to get better at dealing with young men and women prone to violence through our schools and in our neighborhoods. We need to engage in prison reform, and to rework our senseless jailing of so many non-violent offenders (often to great profit for the people who run prisons) and to direct many more resources to lowering alcohol and drug use rather than a continued engagement in a violent drug war. Much of the saved money from that “war” could then go to funding more community approaches to addressing violence. So, yes, reform before and after these violent acts.

Finally, I think of Jared Cano, the teenager who plotted to bomb a high school only a few miles from my home. Cano wanted to make it bigger than Columbine or Virginia Tech. Or now Newtown. He was turned in by a friend. That sort of everyday regulation is as important as anything else. It’s not all gun control, mental health resources, and rapid response. Sometimes it’s a different sort of bravery.

I’ll leave off with Cano’s words before he was sentenced to 15 years in prison.

I don’t want to be the bad guy. I want to be the good guy. The state ain’t gonna make an example. They’re gonna put me in prison. Let me make an example. I had a bad life. Let me change it around and do something good, not bad. Don’t make me the poster child for something evil. Let me be the poster child for something good. Let me do right. Give me a chance to do something right. To make my family proud. I don’t want all these people to think I’m crazy, trying to kill everybody. I want people to look at me as someone who was wrong and changed… and did something right.

[Added 2019. Greg.]

Jason Antrosio has suggested that we include a lot of the commentary because it was really good. So here are the most substantial comments that were made:

A comment by ‘Discuss White Privilege’ on 17 December, 2012:

Posting as DWP so as to keep continuity with comments I’ve made elsewhere that can be related to what I’d like to respond to here.

First, another great post, Daniel. Deeply thoughtful, as always.

Second, increasingly as I think about this tragedy, and certainly in response to my own reflection on the Sandy Hook shooting in comments I posted yesterday to Savage Minds, increasingly I feel dissatisfied with the term “mental illness” and the mental health/mental illness dichotomy. I don’t really think it serves us well, especially not in automatically associating ‘mental illness’ with violence in general, and mass killings (via gun violence) like the one Friday in Sandy Hook in particular.

Too many kinds of *social suffering* and embodied despair are collapsed into the category of ‘mental illness’, in ways that assume that one is either ‘mentally ill’ or not (i.e. ‘normal’, mentally healthy). It assumes that mental health/illness is discrete and not a spectrum (certainly gesturing towards Susan Bordo’s work on anorexia in Unbearable Weight here), in ways that prevent people from realizing that there is a spectrum of mental health, or lack thereof, and that many of the pathologized behaviors or perspectives/motivations that those labeled ‘mentally ill’ may engage in are also shared by those not labeled as mentally ill.

Moreover, I feel deeply troubled by the catch-all-ness of the term ‘mental illness’–encapsulating everything from mild depression to complete psychosis–because it really seem to obscure how different, and race-/culture-/structural-position-specific, the etiology of various conditions may be. This inattention to the specificity of cause helps to further stigmatize people, and to conflate forms of (social) suffering which may in fact be quite different and best understood in more separate categories of embodied suffering. Here I am certainly thinking about Jonathan Metzel’s work on race, implicit bias, and schizophrenia diagnosis (http://www.beacon.org/productdetails.cfm?PC=2087) and the persistent underdiagnosis of depression in black patients, who are instead diagnosed as having some violence-prone form of psychosis and/or impulse-control disorders due to racial stereotyping in diagnosis. I worry about how the current discussion of ‘mental illness’ in catch-all, dichotomized terms worsens such stigmatization and inaccurate diagnosis, especially in relation to larger conversations about who should be seen as a threat for potential violence because they have been labeled ‘mentally ill’.

Like you’ve written above, we need to rethink how we conceptualize and define violence if we are going to be able to better predict who is likely to be the next Adam Lanza. But I would also add that maybe we need to do away with the term ‘mental illness’ as well and find more specific categories for different kinds of embodied/social suffering which we use this term to describe. Such definitional specificity is itself a way to better narrow the range of people we should legitimately identify as deranged, violence-prone, and potential mass killers.

(I am republishing a lot of my ‘legacy content’ from our PLOS Neuroanthropology weblog, which has been taken down, along with many of the other founding PLOS Blogs. Some of these, I am putting up because I teach with them. If you have any requests, don’t hesitate to email me at: greg (dot) downey @ mq (dot) edu (dot) au. I suspect many of the links in this piece will be broken, but I will endeavour to try to slowly rebuild this content. Originally published 3 September 2010.)

The photos that accompanied news releases about quadrupedal people living in Turkey, members of a family that allegedly could not walk except on hands and feet, looked staged when I first saw them. Three women and one man scrambling across rocky ground, the women in brightly coloured clothing, the sky radiant blue behind them, their eyes forward and backsides high in the air – like children engaged in some sort of awkward race at a field day or sporting carnival.

For an anthropologist interested in human motor variation and adaptation, the family looked too good to be true. Subsequent reports and a string of papers confirmed that the families did exist, and they suffered from a condition that came to be called ‘Uner Tan Syndrome’ (sometimes ‘Unertan Syndrome’ or UTS). This story is not new, having already broken and exhausted itself on the waves of internet enthusiasm, but I’ve been wanting to write a sober reflection on the lessons I take from UTS for a while now, and my first major post on our new site seems like a good place.

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Walking on all fours – we’ve all (or virtually all) done it – but most of us eventually become bipedal, even though the developmental pathways to striding around on two feet vary (see Adolph et al. 2010). The motor pattern is so dominant that bipedalism is considered a defining trait of our species, arising earlier in the paleoarchaeological record than many other distinctive hallmarks of humanity. When I teach my introductory human evolution course, students, like generations of evolutionary theorists, are always surprised by the skeletons of ‘Lucy,’ and now ‘Ardi,’ with ape-like brains and increasingly human-like lower bodies (if they’re not surprised, they pretend to be, probably to humour me).

I’ve previously written about my fascination with human flexibility in movement, including extraordinary forms of mobility (in a piece on the ‘Monkey King,’ an amazing Indian building climber), so Üner Tan, Emeritus Professor from Cukurova University in Turkey and member of the Turkish Academy of Sciences, has been generously sending me pre-print articles and other materials on Uner Tan Syndrome. This piece is made possible by his openness and dogged persistence in spreading the word about this remarkable condition.

Tan first described the syndrome in 2005, based initially on five members of the Ulas family from a small village near Iskenderun, Turkey (seen in those initial photos). He later found families in Adana and small villages near Gaziantep and Canakkale for a total of 14 cases (18 cases in total, but four of which may not have the fully fledged condition from other families) (see Tan 2005; 2006a, b, c; 2010).

From the initial reports, when the number of cases was quite small, Nicholas Humphrey and John R. Skoyles from the London School of Economics and Roger Keynes University of Cambridge, in an LSE discussion paper, opined, ‘even if it is indeed a one-off pathological condition, we think there may be anthropological lessons to be learned from it’ (2005: 11). I couldn’t agree more: although rare (though not ‘one-off’), cases of human quadrupedalism are a fascinating window in on the dynamic developmental processes that so reliably – but not inevitably – produce bipedalism in humans.

Symptoms of Uner Tan Syndrome

In the initial cases of Uner Tan Syndrome, the distinctive and defining symptom of quadrupedalism was accompanied by a number of other cognitive and neurological problems, including especially cerebellar irregularities such as ataxia in the trunk, or the inability to coordinate muscle movement, and intellectual deficits such as delayed or absent speech and ‘conscious experience’ problems.

Humphrey, Skoyles and Keynes (2005: 8 ) reported on a number of the cases and found:

signs of cerebellar dysfunction including: intention tremor, dysdiadochokinesis (inability to execute rapidly alternating movements particularly of the limbs), dysmetria (lack of coordination of movement typified by under- or over-shooting the intended position), and nystagmus (involuntary rhythmic eye movement, with the eyes moving quickly in one direction, and then slowly in the other). However, the cerebellar signs are relatively mild, and they are no more pronounced in the quadrupeds than in the one affected brother who walks bipedally.

MRI and PET scans of a number of the families found inferior cerebellar hypoplasia, an underdevelopment in the cerebellum, particularly the vermis, the narrow area between the two brain hemispheres; mild atrophy in the cerebellar cortex and slightly simplified cerebral gyri, or an overly smooth surface; and a reduced corpus callosum, the white matter structure that connects the hemispheres, in three of the families, but not in the fourth (see Tan et al. 2008). Different subjects seemed to have slightly different anatomical abnormalities, but the consistent neurological abnormalities afflicted primarily the cerebrum and overall gyrification, the parallel ridges, of the cerebellar cortex (see, for example, Ozcelik et al. 2008: 4234).

In spite of their other motor deficits, however, their balance (while quadrupedal, that is) was quite stable and the individuals involved were also capable of fine motor coordination. Some of the women affected, for example, did fine needlework. The fact that they were not more severely affected is important because, as Humphrey, Skoyles and Keynes (2005: 9) point out:

The capacity for walking upright is highly resilient in human beings. In fact humans typically remain bipedal in the face of much greater obstacles to balance and coordination than those experienced by the subjects we have described here. Individuals with bilateral labyrinthine dysfunction, and loss of lower limb proprioceptive sensation are nonetheless typically bipedal. Bipedality can even occur in the complete absence of the cerebellum. There is a recent report of a young man with congenital agenesis of the cerebellum who nevertheless learned to walk and ride a bicycle.

Why can’t they walk?

Because of the pattern of Uner Tan Syndrome within families and its association with consanguineous marriage, or marriage between cousins, most researchers initially suspected that an autosomal recessive gene mutation might be involved.

Sure enough, in 2008 in an article in the Proceedings of the National Academy of Science, Tayfun Ozcelik and colleagues (2008a) reported that the quadrupedal families had a cluster of related genetic abnormalities, mostly to chromosomes 9p24 and 17p, although one affected family did not have abnormalities to either of these chromosomes (for a review, see Tan 2010). In two of the four Turkish families, the abnormality occurred with the VLDLR gene on 9p24, which encodes the very low-density lipoprotein receptor, also implicated in another genetic disorder, Disequilibrium Syndrome (DES-H), where balance and movement problems are also compromised. Although DES-H sufferers have severe walking difficulties, however, no reported cases walk quadrupedally.

Cross-checking against unaffected family members and other members of the community confirmed the likelihood that a mutation to VLDLR might be the culprit, although a cautionary note is that one family member who had the genetic abnormality could walk normally.

VLDLR is involved in the reelin pathway, a glycoprotein regulated mechanisms that moderates neuronal positioning, alignment and migration in the cerebellum; reelin binds to the VLDLR gene and helps get neuroblasts in the right place and configuration for the cerebellum (for a more detailed discussion, see Türkmen et al. 2008). Mice with impaired reelin genes (RELN) or VLDLR abnormalities wind up with abnormal cerebellae, although VLDLR abnormalities can be asymptomatic in mice, only revealed on autopsy (or presumably, if they stuck the little mice in little mice-sized MRIs and got them to sit still) (see Trommsdorff et al. 1999).

However, Ozcelik and colleagues suggested after a thorough gene mapping study that Uner Tan Syndrome was genetically heterogeneous, even in the limited sample of the four Turkish families (2008a: 4234). I’ll come back to that at length in the next post because I think calling every example of habitual and facultative quadrupedalism an example of a single ‘Uner Tan Syndrome’ is misleading, but misleading in a direction that forces us to question whether Uner Tan and others cases of quadrupedalism are actually demonstrating something much broader than a gene causing a disorder, the extreme cases of VLDLR genetic abnormality being only part of the picture.

Tan and colleagues’ (2008) earlier PET and MRI-based study of the original two families likewise showed divergent results: the UTS sufferers in one family had central vestibular deficits, leading to noticeable abnormalities in the brain scans (cerebellar and vermial atrophy and reduced metabolic activity), whereas the second family had peripheral vestibular deficits and ‘quasi-normal’ scans. The team acknowledged that ‘the quadrupedal gait may have different origins, such as developmental delay in the transition from quadrupedality into bipedality during babyhood’ (ibid.: 335). In simple terms, different mechanisms appeared to be producing the extremely unusual results in the families, the development of bipedality stymied by a range of possible obstacles. The diversity was striking because the condition was so rare; if different abnormalities could produce it, why was habitual human quadrupedalism so rare?

Cerebellum problems and gait ataxia

Abnormalities in the cerebellum often lead to gait ataxia or a kind of disordered, ‘drunken’ form of walking. As Morton and Bastian (2007) discuss, damage to the cerebellum likely leads to a number of effects including difficulties in modulating rhythmic movement, even though the movements could be generated by the brainstem and spinal chord. Disruption of this higher order movement orchestration function might explain the instability of walking with cerobellar hypoplasia because, although individuals can produce leg movements, they would have a harder time coordinating the relations between those leg movements. Walking successfully isn’t just doing leg movements but getting the rhythmic oscillations of the limbs synchronized so that one off-step does not disrupt the smooth transfer of weight or trigger a cascade of increasingly awkward or unbalanced movements that might eventually cause the walker to topple over.

In short video clips that Prof. Tan has sent me, a young boy with UTS can be seen standing up and trying to move his feet, but he starts to wobble, apparently due to an inability to control the steps, and quickly falls down. Admittedly, the falling looks well rehearsed, a kind of slumping straight down, as if he isn’t trying to stay up, but that’s likely an effect of his previous experience trying to walk bipedally. In contrast, when walking on hands and feet in another clip, he’s not wobbly at all, but moves smoothly and confidently, quickly getting about a small house.

In addition to coordination problems, damage to some portions of the cerebellum can lead to difficulties maintaining balance in a host of postures, including sitting and standing, as well as walking. The Uner Tan Syndrome cases, however, seem to have problems primarily with walking, and could stand, albeit in awkward positions in some cases. Although vertical posture control conceivably might be compromised to some degree with UTS, the impairment is not so great as to inhibit standing, perhaps because the posture does not exceed the capacities of the impaired cerebellum (patients with cerebellum lesions, however, do often have problems standing upright).

Finally, Morton and Bastian (2007, p. 83) suggest that the cerebellum facilitates adapting movements to perturbations, preserving smooth functioning in shifting situations. Although separating this from the first function in the descriptions of the individuals with Uner Tan Syndrome is difficult, especially working from the published papers alone and a few videotapes, this might also help explain the specific quadrupedal movement. Several of the papers on UTS describe that the subjects could stand but quickly reverted to a four-limbed stance when they tried to step forward. We don’t know if, given ideal situations, the UTS patients might be able to walk, only losing balance when they can’t compensate for variations in conditions. Just judging from the little tape I’ve seen, I think the problem is more profound than this, but it’s hard to tell as learned inability – a lifetime of being unable to walk bipedally – might deter any serious attempt in the older children.

Damage to the cerebellum usually produces distinctive patterns of motor problems; stroke-related insult or gunshot wound to the upper part, for example, can produce problems with gait and balance whereas similar injuries to the lower cerebellum might affect movements of the hands and arms. Fine motor control tends to be affected more by lateral damage; whole body by medial injury.

The Uner Tan Syndrome patients, however, seem to control their bodies, except for their torsos, reasonable well with some issues about aiming movements, tremors, and the like. And yet they lose their ability to walk upright, a remarkably resilient capacity, while developing marked, even extraordinary compensatory facility in quadrupedal movements.

That is, if we focus only on their deficits, we miss the fact that they also have this exceptional ability, one that normal, bipedal humans would be hard-pressed to imitate. Try moving about in a ‘bear walk’ for a while (I have, as the next post will explain), and you’ll quickly realize that, if this is the ‘default’ body position when you can’t balance, most of us have lost the ‘default’ through disuse.

Is Uner Tan Syndrome genetic?

Confronted with the evidence that the genetic abnormalities among the Turkish cases were heterogeneous, and that in one case, an abnormality could not be found, and with a sibling who had the mutation but was able to walk normally, some researchers have concluded that the condition is not solely genetic in origin.

In a working paper (2005) and in a response (2008) to Ozcelik and colleagues’ (2008) piece in PNAS, Humphrey, Skoyles and Keynes offer a more complex etiology for quadrupedalism, one that takes into account the social situation in which a person with equilibrium difficulties finds him- or herself. Humphrey’s team suggests that the ataxia alone would not produce the condition: ‘additional factors must have been at work, operating in the childhood environment, that combined with the ataxia to produce the unprecedented outcome’ (Humphrey et al. 2005: 9).

Humphrey and colleagues (2008: 10) suggest that a convergence of elements more likely explains Uner Tan Syndrome, pointing to a study of children’s movements that highlighted how the ‘bear-crawl’ might form a rare but surprisingly stable intermediate stage that could supersede or entirely replace ‘knee-crawling’:

The bear-crawl has several advantages over more typical knee-crawling, and it can temporarily prove to be an especially good way of getting around. Indeed Ales Hrdlicka, who seventy five years ago wrote a definitive (though now largely forgotten) treatise on this kind of crawling, Children Who Run on All Fours, remarked that “The most common effect of the all- fours method of progression appears to be more or less of a delay in walking erect. . . These children are quite satisfied with their easy and rapid on-all-fours, and were they left to their own devices and not influenced by other examples, they might possibly keep on, on hands and feet, for a longer time if not indefinitely.”

In other words, ‘bear-crawling’ works, so when children discover it (approximately 5% of the time in American children), the development of walking can be delayed because the incentives to abandon quadrupedal movement when doing it on the knees — slowness, difficulty, lack of mobility — are not as great in the ‘bear-crawlers.’ They get better at moving without having to get bipedal.

Humphrey, Skoyles and Keynes (ibid.) go on to suggest a scenario where that ‘bear-crawling’ might continue, potentially into adulthood:

suppose now that an infant who was a bear-crawler were also to have a congenital brain condition which made balancing on two legs unusually difficult. Suppose moreover that such an infant were, in Hrdlicka’s words, to be less than usual “influenced by other examples” (or, more to the point, more than usual influenced by similar examples within its own family), and furthermore that the infant were to be more than usual “left to its own devices” by its caretakers. The stage might well be set for a version of the bear-crawl gait to be carried on into later life, becoming modified and improved until it did in fact become an effective substitute for bipedalism.

As collaborating evidence, although hardly proof, the authors offer that, 1) the mother reported all of her nineteen children were ‘bear-crawlers,’ even those that became bipedal; 2) once one child permanently adopted quadrupedal movement, subsequent children would have had a mature model; 3) the father regarded the children as ‘gifts from God’ with which he could demonstrate love; and 4) a local doctor said that the family passively accepted the condition and did not attempt physiotherapy. Both the third and fourth point would be a point of contention with other researchers.

Türkmen and colleagues (2008: 1073) reach a similar, albeit less elaborate, conclusion after considering the comparison between the Uner Tan Syndrome cases with Disequilibrium Syndrome: although the genetic mutation causing cerebellar hypoplasia and subsequent ataxia is necessary, it is not sufficient to explain human quadrupedalism.

Confronted by Humphrey and his colleagues in a published letter, Ozcelik and his research team (2008b) intensify the argument for a genetic origin for Uner Tan Syndrome. From the final paragraph of their letter, the reason for the intensity of their response is clear: the researchers are aware that some popular accounts of the Turkish families suggest that the parents’ religious beliefs, their understanding of their children’s condition as divinely ordained, contributed to the condition (the authors cite this piece by Anjana Ahuja in The Times Online). Acknowledging developmental dynamics might contribute to a ‘blame the victims’ family (or religion)’ diagnosis. In contrast, Ozcelik and colleagues (2008a: 4236) wrote in the earlier article, and confirm in their letter (2008b), that several of the families actively sought medical and remedial help, including one unaffected sibling who became a physician, and one family discouraged quadrupedal walking without success. (Ironically, Tan 2010: 81, contradicts this assertion.)

Is quadrupedal walking an atavism?

Throughout the discussion of Uner Tan Sydrome, many of the researchers suggest that the quadrupedal walking pattern might be an atavism, a resurgence of a trait from a more distant ancestor that had otherwise disappeared, like a human caudal appendage (a tail) or hind limbs on a dolphin or whale (e.g., Tan et al. 2008; on atavisms, see Hall 1984; specifically on tails, see Bar-Moar et al. 1980). For example, Humphrey and colleagues (2005: 11) ask:

Given that all five individuals developed the same adult gait, as if following the same developmental programme, there are grounds for asking: where could the “memory” for such a programme have come from? Does it in fact represent an atavistic trait, that has been exposed – possibly for the first time in recent human history – by the remarkable conjunction of circumstances?

Brian Hall (1984) defines atavisms as ‘reappearance of a lost character (morphology or behaviour) typical of remote ancestors and not seen in the parents or recent ancestors of the organisms displaying the atavistic character.’ Ironically, although they disagree on the cause of the syndrome, many of the writers seem to agree that quadrupedalism is an evolutionary ‘rediscovery’ or atavism, an assertion which I find pretty difficult to demonstrate.

Prof. Tan (2006c; 2008), himself, has argued that UTS may be a rare case of ‘reverse evolution’ or ‘devolution,’ an argument that has been strongly resisted by other researchers (see, for example, Herz et al. 2008). Most would argue that the concept of ‘devolution’ or ‘reverse evolution’ is simply not coherent, assuming that evolution is normally, necessarily ‘progressive,’ an understanding anathema to some of the most basic evolutionary principles about irreversibility and non-teleology (that evolution isn’t directed ‘progress,’ just variation, survival and change in relation to shifting selectie environments).

In fact, the argument that human ancestors might have once walked on the ground like chimpanzees (knuckle-walking) or walked quadrupedally on the ground at all prior to becoming terrestrial bipeds has been losing ground in recent years as evolutionary theorists increasingly argue that terrestrial bipedalism may have emerged directly from arboreal ways of moving. That is, instead of first descending to the ground and walking like our chimpanzee or gorilla cousins, instead, our ancestors may have developed other forms of aboreal bipedalism and quadrupedalism that they transferred to the ground (see Thorpe et al. 2007; Stanford 2006).

The recent reports about the hand and wrist structure of ‘Ardi,’ the remains of an Ardipithecus ramidus, seem to support the arboreal bipedalism hypothesis and to suggest that palmigrade quadrupedalism may have, in fact, been an ancestral form of locomotion. Ardi’s skeleton demonstrated some of the hallmarks of bipedalism with no trace of the reinforced knuckle and wrist structure that tends to accompany knuckle-walking. Among the long-awaited analyses of Ardi that appeared last year in Science, Owen Lovejoy and colleagues (2009) specifically discussed the forelimb and hand, detailing how this species of hominid might have moved about (for a summary). The long and short is that Ardipithecus likely moved quadrupedally in trees (carefully walking atop branches) and bipedally on the ground, although this is subject to dispute.

If Ardipithecus was an arboreal quadruped and a terrestrial biped, the argument that terrestrial quadrupedalism is an atavism starts to look a little less convincing. Either we’d have to assume that the pattern of ground movement is a very, very old atavism, predating the move of primate ancestors into an arboreal niche (and thus probably predating the rise of true primates somewhere around 50-80 mya) or disregard the mechanical differences between moving in trees and moving on the ground, including the importance of grasping branches while moving (which Ardipithecus would have been able to do with both hands and feet).

I’m less convinced of the argument that quadrupedalism is an ‘atavism’ because I don’t think quadrupedalism is so difficult to explain that we need to assume a left-over ‘program’ in the brain stem for quadrupedalism getting reactivated. As I’ll discuss in the second post, I think quadrupedalism is ‘closer to the surface’ in humans than we tend to recognize, so becoming habitually quadrupedal is not such a great leap back in devolutionary terms, and that dynamic models of how locomotion emerges better explains, not just human quadrupeds, but also some pretty exotic bipeds that I want to add to the discussion.

Even the fact that the various sufferers of Uner Tan Syndrome develop diverse gaits undermines the argument, in my opinion, that the motor pattern results from a motor ‘program,’ atavistic or otherwise. The initial five subjects from the family in Iskenderun, for example, had two distinct forms of moving, the one male walking with his legs much closer together, whereas his sisters splayed their rear legs. Later quadrupedal walkers studied by Prof. Uner Tan, which I’ll discuss in the next post, relied on bent legs, fundamentally changing the biomechanics of the movement, shifting the position of the pelvis, the angles of the joints, the position of the head, and a host of other crucial variables.

Things get more interesting…

(Well, at least in my opinion.) Were this the state of the situation, I’d probably be interested, but I wouldn’t be posting it as my first substantive column on our new PLoS blog. Consanguineous marriage, genetic abnormality, terrestrial quadrupedism, suggestions that human quadrupedalism might be an evolutionary atavism… heady stuff.

But Dr. Tan keeps finding more and more cases of children and adults who walk on all four, emailing me articles of ‘new cases’ of UTS, and many are clearly not cases of fully blown Uner Tan Syndrome. Some have normal cognitive functions, only convert to quadrupedalism when they’re in a hurry, become quadrupedal later in life, or obviously move in unusual ways due to paralysis from childhood polio.These cases stretch the definition of UTS to the breaking point, but they fill out our account of human quadrupedalism.

I must confess, I’ve never met Uner Tan, and his emails to me are brief, so I have very little sense of what he’s like, but he’s clearly had his interest piqued by these families that he initially documented, so he’s got at least a mild fascination with people who move this way. For that, I’m sympathetic because I’ve got it, too. But the implications of these additional quadrupeds suggests to me that we need to move in a different direction to understand human diversity in ways of moving, away from thinking solely in terms of genetic abnormality and evolutionary atavism….

But to read about that, I’m afraid you’re going to have to turn to Part 2, because this post is getting too long. Come back tomorrow for Part 2: ‘2 legs good, 4 legs better’: Uner Tan Syndrome, part 2.

For more information:

The inimitable John Hawks weighs in (2006), On pathology and evolution, or, the Turkish tetrapods

Anthropology.net on Mutatons in VLDLR gene in the Quadrupeds from Turkey discussed the 2008 discoveries of genetic abnormalities reported in the Proceedings of the National Academy of Sciences.

BBC documentary, ‘The Family that Walks on All Fours’ (17 March 2006)
PBS’s the Family that Walks on All Fours: A Look at Human Quadrupeds
The trailer is available on You Tube.

Image:
Photo of Ulas family from Anthropology.net.

Photo of Prof. Üner Tan from Neuroanatomy (2004) Volume 3 page 29.

References:

Adolph, Karen E., Lana B. Karasik, and Catherine S. Tamis-LeMonda. (2010). Motor skills. In M. Bornstein (Ed.), Handbook of cultural developmental science (pp. 61-88). New York: Taylor & Francis. (Available from K. E. Adolph’s publications webpage)

Bar-Moar, J. A., K. M. Kesner, and J. K. Kaftori. (1980). Human Tails. The Journal of Joint and Bone Surgery 62-B(4): 508-510.

Hall, Brian K. (1984). Developmental mechanisms underlying the formation of atavisms. Biological Reviews, 59, 89-124 DOI: 10.1111/j.1469-185X.1984.tb00402.x

Herz J, Boycott KM, & Parboosingh JS (2008). “Devolution” of bipedality. Proceedings of the National Academy of Sciences of the United States of America, 105 (21) PMID: 18487453

Humphrey, Nicholas, Stefan Mundlos, & Seval Türkmen (2008). Genes and quadrupedal locomotion in humans. Proceedings of the National Academy of Science , 105 (21) DOI: 10.1073 pnas.0802839105

Humphrey, N.; Skoyles, J.R. & Keynes, R. (2005). Human hand-walkers: five siblings who never stood up [online]. London: LSE Research Online. Available at: http://eprints.lse.ac.uk/archive/00000463

Hrdlicka, A. 1931. Children who run on all fours, and other animal-like behaviors in the human child.New York: McGraw-Hill.

Lovejoy CO, Suwa G, Simpson SW, Matternes JH, & White TD (2009). The great divides: Ardipithecus ramidus reveals the postcrania of our last common ancestors with African apes. Science (New York, N.Y.), 326 (5949), 100-6 PMID: 19810199

Susanne M. Morton,, & Amy J. Bastian (2007). Mechanisms of cerebellar gait ataxia The Cerebellum, 6(1), 79-86 DOI: 10.1080/14734220601187741

Tayfun Ozcelik, Nurten Akarsu, Elif Uz, Safak Caglayan, Suleyman Gulsuner, Onur Emre Onat, Meliha Tan, & Uner Tan (2008). Mutations in the very low-density lipoprotein receptor VLDLR cause cerebellar hypoplasia and quadrupedal locomotion in humans. Proceedings of the National Academy of Sciences, 105 (11), 4232-4236 DOI: 10.1073/pnas.0710010105

Ozcelik, Tayfun,, Nurten Akarsu,, Elif Uz,, Safak Caglayan,, Suleyman Gulsuner,, Onur Emre Onat,, Meliha Tan,, & Uner Tan (2008). Reply to Herz et al. and Humphrey et al.: Genetic heterogeneity of cerebellar hypoplasia with quadrupedal locomotion. Proceedings of the National Academy of Sciences, 105 (23) DOI: 10.1073 pnas.0804078105

Stanford CB (2006). Arboreal bipedalism in wild chimpanzees: implications for the evolution of hominid posture and locomotion. American journal of physical anthropology, 129 (2), 225-31 PMID: 16288480

Tan, Meliha, Sibel Karaca, and Uner Tan. (2010). A New Case of Uner Tan Syndrome—with Late Childhood Quadrupedalism. Movement Disorders, 25 (5), 652-653 DOI: 10.1002/mds.22951

Tan, U. (2005). Unertan Syndrome: Quadrupedality, primitive language, and severe mental retardation; a new theory on the evolution of human mind. NeuroQuantology, 4, 250–255. (Abstract and downloadable pdf)

Tan, U. (2006a). A new syndrome with quadrupedal gait, primitive speech, and severe mental retardation as a live model for human evolution. International Journal of Neuroscience, 116, 361–369. (Abstract and downloadable pdf)

Tan, U. (2006b). Evidence for “Unertan Syndrome” and the evolution of the human mind. International Journal of Neuroscience, 116, 763–774. (Abstract and downloadable pdf)

Tan, U. (2006c). Evidence for “Uner Tan Syndrome” as a human model for reverse evolution. International Journal of Neuroscience, 116, 1539–1547. (Abstract and downloadable pdf)

Tan, Uner (2007). A Wrist-Walker Exhibiting No “Uner Tan Sydnrome”: A Theory for Possible Mechanisms of Human Devolution Toward the Atavistic Walking Patterns. International Journal of Neuroscience , 117 (1), 147-156 DOI: 10.1080/00207450600936866

Tan, Uner. 2008. Discovery of Unertan syndrome and reverse evolution: as an “Aha!” experience. NeuroQuantology 6, 80-3. (abstract)

Tan, Uner. 2010. Uner Tan Syndrome: History, Clinical Evaluations, Genetics, and the Dynamics of Human Quadrupedalism. The Open Neurology Journal 4, 78-89. (abstract)

Uner Tan, Sadrettin Penccedile, Mustafa Yilmaz, Ayhan Oumlzkur, Sibel Karaca, Meliha Tan, & Mehmet Karatascedil (2008). “Unertan Syndrome” in two Turkish Families in Relation to Devolution and Emergence of Homo Erectus: Neurological Examination, MRI, and pet Scans International Journal of Neuroscience, 118, 313-336 DOI: 10.1080/00207450701667766

Tan, Uner, & Meliha Tan (2009). Unertan Syndrome: A New Variant of Unertan Syndrome: Running on All Fours in Two Upright-Walking Children International Journal of Neuroscience, 119 (7), 909-918 DOI: 10.1080/00207450902828050

Thelen, E., & Smith, L. B. (1998). Dynamic systems theories. In W. Darnon and R. M. Lerner (Eds.), Handbook of Child Psychology: Vol. 1. Theoretical Models of Human Development, 5th ed. New York: John Wiley & Sons, 563–634.

Thelen, E.,, & Ulrich, B. D. (1991). Hidden skills: A dynamic systems analysis of treadmill stepping during the first year Monographs of the Society for Research in Child Development, 56 (1), 1-98 DOI: 10.2307/1166099

Thorpe, S. K. S.,, R. L. Holder,, & R. H. Crompton (2007). Origin of Human Bipedalism As an Adaptation for Locomotion on Flexible Branches Science, 316 (5829) DOI: 10.1126/science.1140799

Trommsdorff M, Gotthardt M, Hiesberger T, Shelton J, Stockinger W, Nimpf J, Hammer RE, Richardson JA, & Herz J (1999). Reeler/Disabled-like disruption of neuronal migration in knockout mice lacking the VLDL receptor and ApoE receptor 2. Cell, 97 (6), 689-701 PMID: 10380922

S Türkmen,, K Hoffmann,, Osman Demirhan,, Defne Aruoba,, N Humphrey,, & S Mundlos (2008). Cerebellar hypoplasia, with quadrupedal locomotion, caused by mutations in the very low-density lipoprotein receptor gene European Journal of Human Genetics, 16, 1070-1074 DOI: 10.1038/ejhg.2008.73

(I am republishing a lot of my ‘legacy content’ from our PLOS Neuroanthropology weblog, which has been taken down, along with many of the other founding PLOS Blogs. Some of these, I am putting up because I teach with them. If you have any requests, don’t hesitate to email me at: greg (dot) downey @ mq (dot) edu (dot) au. I suspect many of the links in this piece will be broken, but I will endeavour to try to slowly rebuild this content.)

At the beginning of the film clip, Bajau fisherman Sulbin sits on the side of a boat on the coast of Borneo, gulping air, handling his speargun.  And then, he drops into the water.  The footage suddenly changes and becomes arresting: silent, dreamy, slow, and so blue.  Sulbin strokes deliberately and descends until he strides along the bottom of the ocean, holding his breath, and hunts for fish through handmade goggles. [I’ve had to get a new version of the video clip, 2019.]

Finally, after a couple of minutes, he spears a fish and heads for the surface.  The narrator tells us that Sulbin could stay down twice as long and dive deeper if necessary.  Most viewers, unfamiliar with free diving, exceptional if they can hold their breath longer than thirty seconds, are quite likely to be shaking their heads by the end of the clip, wondering at the ability of the human body to adapt to life in water.  Life as an amphibious human can appear so alien that it’s stranger than science fiction, but painfully beautiful to watch.

I stumbled across the video clip in part because of my academic interest in free diving. Earlier this month, I was supposed to attend a free diving workshop in New Zealand with one of the sport’s world record holder, Will Trubridge (or see the story on the Times Online).  The workshop fell through at almost the same time I was diagnosed with multiple hernias, so my first free diving experience likely wouldn’t have worked out – I’m still hoping to do it as part of my ethnographic research on extraordinary human performance in the near future.

But the clip of Sulbin on the BBC series, Human Planet episode, Oceans, has inspired me to write a little bit about Homo aquaticus (kidding), adaptation, culture, and what this sort of remarkable human adaptation might imply for the idea of ‘human nature.’

Sulbin’s ability is remarkable, but like so many exceptional human skills, it relies not on innate difference from other individuals, but on the steady cultivation of peculiar changes in the body and in how it is experienced.  What I hope to suggest is that amphibious humans point to the most basic fact of human nature: that we seem particularly adept at finding ways to adapt ourselves – biologically, psychologically, behaviourally, technologically – to a host of niches that then rebound back upon us and shape how we develop.  We are a peculiar self-made species.

This piece is probably best seen as one in a series I’ve been crafting on how human adaptation to situations that we place ourselves in map out the envelope of our bodies’ malleability.  Human skills and adaptation show us how our brains and nervous systems can be trained to do amazing things.  Frequent readers will know that I think much of the discussion of ‘human nature,’ carried out by — to put it nicely — exceptionally sedentary theorists, severely underestimates what our bodies are capable of doing.

Too often, in discussions of human adaptation, we allow a flabby distinction between three basic types of adaptation: genetic, phenotypic (or physiological), and cultural (or technology).  What I’ve been playing with, and will return to at the end of this piece, is the inseparability of these, especially the last two: physiology and culture.  The Bajau fisherman Sulbin shows us how biology and culture are inseparable because what he does ends up shaping his body, but only because he grew up around people who knew how to manage becoming human in this distinctive amphibious way and because his adaptations play upon how his nervous system works, including some intriguing quirks.

If you’re mad keen to learn more about human adaptation and my ongoing obsession, you might check out samples of my work on human quadrupedalism (part two), barefoot running, barefoot climbing, and even overhand throwing (the piece is specifically on ‘throwing like a girl’).  I’ll be posting more in the months to come, so if you’re interested in what the human body can be made to do, pay us a return visit periodically.

‘Sea gypsies’ in Southeast Asia

Sulbin is a member of a number of groups who live wholly or partially as oceanic nomads or sea foragers in South-East Asia.  As the BBC website explains:

Few peoples have a deeper connection with the sea than the Bajau Laut of South-East Asia. Sometimes known as “sea gypsies”, they live in house boats or stilt houses built on top of coral reefs and when they do spend the occasional night on solid ground they often report feeling ‘landsick’.

Malaysia’s best Bajau free-divers can dive to depths of over 20 metres and stay there for several minutes on a single breath as they go in search of fish. And as if that weren’t enough, studies on some “sea gypsy” children from Thailand and Burma show that they have unusually good underwater-vision because their eyes have adapted to the liquid environment.

The Bajau Laut’s livelihood is traditionally totally dependent on the resources of the sea so spear-fishing is vitally important to them, but different cultures have very different ways of catching fish.  (BBC website).

I won’t go into the ethnographic material on the Bajau and other groups called ‘sea gypsies’ (such as the Moken, who live along the coasts of Thailand, Burma and increasingly into Malaysia).  If you’re interested, I’ve placed some links to more material on the Moken and other groups at the end of this article.  Some of the groups experienced a recent spike in interest when they apparently avoided serious casualties in the Boxing Day Tsunami of 2004 because they ‘saw signs in the waves’ of the trouble to come.

This post is really about adapting to diving, and that happens a lot more broadly than just in ‘sea gypsy’ populations.  Although SCUBA and other techniques are replacing breath-hold diving, traditional divers cultivated incredible abilities in the production of sponges in Greece, and pearls in places like Polynesia and the Persian Gulf.  The practice is still widespread among recreational divers, competitive divers, and even in some industries, such as among seafood harvesters in Japan and Korea, where an estimated 20,000 professional divers still worked with minimal equipment as late as the 1990s (see Park et al. 1990, cited in Ferretti 2001).

Learning to ‘hold’ your breath

Human ‘adaptation’ to water is both conscious and unconscious, as so many things about human behaviour.  Even the most basic adaptive reflexes have to be shaped and elaborated, although they can often be learned in implicit, indirect ways or found in basic form very early.  For example, one of the most reliable reactions to a startling new sensation is to gasp, a potentially deadly maladaptive approach to dealing with being dunked in the water.  Fortunately, when water hits the pharynx or larynx, glottal spasms clamp the throat shut with a glottal spasm in part of what is referred to as the ‘diving reflex’.

If we’re going to enjoy the whole underwater swimming experience, however, we’ve got to be taught to stop the airway voluntarily and close the glottis muscularly, or to exhale. It’s more pleasant than just plunging into the water and trusting that the ‘diving reflex’ will save you from winding up with a couple of lungs full of the stuff by triggering a glottal spasm.  In other words, the reflex has to be cultivated into a skill.

The online web resource eHow suggests, in How to Teach a Baby to Hold Breath Underwater, that you first condition an infant by essentially an associative learning process where dipping a washcloth in water is followed shortly by dripping water over his or her face.  The writer advocates following this up at a pool with a learned association between ‘1… 2… 3…’ and subsequently being splashed in the face, later substituted by short immersion.  The diving reflex can cue the early learning, but the goal is to build a more robust voluntary behaviour and to do it in a way that doesn’t so traumatize the kid that he or she never wants to go back to swimming lessons.

When I taught swimming lessons last century (it seems like that long ago), this sort of learned association was also the way that we taught infants, but we also, if we had a particularly difficult case of a gulper, tried to teach the infant to hold its breath by blowing into its face.  Either way, though, the early stages of teaching breath holding, at least in my experience, almost always involve a few rough first attempts, with coughing and crying almost inevitable.  With the slightly older kids, you could teach them to exhale as they went under (‘blow bubbles’), but some coughing and inhaled water, again, was likely inevitable at some point.

My point is that holding your breath is not something that humans do naturally, although breath control is actually really important for speaking and other human abilities.  Breath holding in water may be an easy reaction to instill, but it relies upon someone teaching you or some sort of training, building on top of a more primitive, widely held reflex. Since my father is a non-swimmer, I know firsthand that there’s nothing ‘natural’ about being able to survive in water.

In fact, the Alliance for Safe Children (an Asian NGO) points out that, in some parts of the world, drowning is one of the leading causes of child mortality, contributing approximately fifty deaths each dayin Bangladesh (in contrast, that’s Australia’s typical annual total).  According to the WHO, drowning is the third most common cause of unintentional injury death worldwide (WHO ‘Drowning,’ fact sheet #347).

The ‘breakpoint’: involuntary breathing

Your body wants you to breathe as the oxygen you took in with your last breath gradually converts to carbon dioxide.  A powerful involuntary mechanism overrides most intentional attempts by humans to hold their breath, as M. J. Parkes (2006) outlines, long before you are actually in any distress. Try to hold your breath until you pass out, and most people will simply not be able to manage it (I’m not actually recommending this experiment).

As we hold our breath, above or below the water, the body slowly converts the oxygen our bodies store in our lungs and blood into carbon dioxide.  Levels of oxygen decrease (to hypoxia), and carbon dioxide increases (to hypercapnia).  Left long enough, the lack of oxygen will eventually cause brain death from cerebral hypoxia and heart attack, but most of us get nowhere close to dangerous levels when we hold our breath. As Parkes writes (2006: 2-3):

although the simplest clue to the breakpoint mechanism should emerge from identifying any manoeuvre enabling breath-holding to unconsciousness, scientific reports of breath-holding to unconsciousness are rare and inconsistent, despite popular mythology. Schneider (1930) stated that ‘it is practically impossible for a man at sea level to voluntarily hold his breath until he becomes unconscious’, and subsequent scientific literature supports this in adults. [Anecdotal descriptions of losing consciousness describe subjects breath-holding at low barometric pressures, with low oxygen mixtures or with severe voluntary hyperventilation…]

In fact, Fitz-Clarke (ibid: 57) reports that ‘almost all extreme breath-hold divers have experienced loss of consciousness upon emersion in their career’ likely as a result of the carbon dioxide build-up, especially with depressurization on the ascent from deep free dives.  In addition, partial, temporary loss of motor control (called ‘sambas’ by the divers) were relatively common in the competition Fitz-Clarke observed.

(The practice of diving, especially the pursuit of records, is still dangerous, so much so that in 1991, the World Conference of Underwater Activities stopped recognizing absolute records for depth and started to more tightly restrict competitive free diving.  The drive to go deeper and deeper, using more and more elaborated assistance, was putting lives at risk.  In contrast, in the competition Fitz-Clarke observed, safety standards were very high, as they are in sanctioned free-diving events, with assistance divers in the water with competitors and all participants carefully observed.)

The ‘breakpoint’ mechanism, when you feel an almost overwhelming impulse to breath, turns out to be a convergence of a number of reflexes that are quite difficult to study. One key component, however, is chemoreceptors that detect the levels of gas in the blood, especially carbon dioxide surplus.  We know chemoreceptors play a role because boosting oxygen levels and decreasing absorbed carbon dioxide in the bloodstream — for example, by gulping air as Sulbin appears to be doing — can extend the amount of time that you hold your breath, although many physicians will caution against it.

But research into breath holding has found that there’s no fixed threshold, either of oxygen or carbon dioxide, that will lead to involuntary breathing, so researchers like Parkes (2006) have argued that chemorecption alone cannot explain the break point.  Neurological research has shown that the central nervous system begins to try to restart respiration, including through the diaphragm, before the impetus to breathe becomes almost irresistible to an untrained individual.

Parkes argues that the central respiratory rhythm, an autonomic rhythm like the cardiac rhythm, persists during a breath hold, even though voluntary breath holding suppresses it active expression.  This means that breath-holders are not so much stopping their breathing voluntarily as they are holding their chests open and resisting the respiratory rhythm. Parkes (2006: 8-9) points to a range of evidence which suggests that the respiratory rhythm intensifies during the breath hold, even causing more widespread respiratory-anticipating reactions like ‘trachial tugging’ in the lead up to the break point.

Similarly, in a competitive static apnea event, in which divers hold their breaths in stationary positions, Fitz-Clarke (2006: 59) found that most divers experienced involuntary contractions of the diaphragm several minutes into the event. Successful competitors were able to continue to hold their breath even though the nervous system sought to reinitiate breathing.

In other words, as the voice-over says with the video of Sulbin, exceptionally long breath holding requires that a person learn to resist powerful involuntary reflexes, especially spasms in the diaphragm as it attempts to contract in order to re-initiate breathing.  When you breath hold, you are not so much ‘running out of air’ as you are fighting powerful impulses to breath when you don’t really need the oxygen yet. Breath holding like Sulbin is doing is the active over-coming of automatic processes by conscious suppression; it’s ignoring pain and involuntary muscle actions because you know you don’t need to do what they’re screaming at you to do.

Without these impulses, how long could you hold your breath?  Many people may have heard that three to five minutes without oxygen will cause irreparable brain damage, so they might assume that about four to five minutes would be the maximum that a person could hold his or her breath.  They would be wrong.

Breath holding is less dangerous to the brain then cardiac arrest, because during a breath hold, the brain is still connected to oxygen stores in the lungs and the body quickly starts making adjustments to stretch this oxygen store last as long as possible (Fitz-Clarke 2006: 60).  In fact, in static apnea (stationary breath holding) competitive breath holders can last five to nine minutes as the body puts into place a range of survival responses and competitors learn to make the most of the oxygen they’ve got.

Making your last breath last

So how can you make your breath last as long as possible if you’re going to have to fight your body to do it.  Not all people have the same ‘breakpoint,’ of course, and even the same subjects can demonstrate a wide range of breath-hold times, increased by distraction and by repeated trials (Parkes 2006: 2).  But a range of techniques can stretch out your oxygen supply.

First, if you know what to do before entering the water, you can start out ahead. Although physicians warn not to hyperventilate or gulp air prior to diving, Fitz-Clarke (2006: 56-57) found in a study of a competitive free diving event that

almost all athletes employed “lung packing” in the water prior to submersion. This is an inspiratory technique for hyperinflating the lungs using the pharyngeal and glottic muscles in a repetitive manoeuvre resembling gulping or swallowing

‘Lung packing’ or hyper-inflating the lungs to some degree (not to dizziness) before diving is discouraged for a number of reasons, but it can put more air into the lungs to start with, boost the blood oxygen level in the blood slightly, and – most importantly and dangerously – suppress the level of carbon dioxide in the body.  With less carbon dioxide, you’re breathing reflex is going to be delayed, but this may also be the reason that free diving participants pass out with some frequency; they run low on oxygen before carbon dioxide levels get high enough to prompt breathing.

The simplest way to make your breath last is to do as little as possible and to stay calm. The record for stationary breath-holding is much longer than the record for any dynamic activity.  In addition, the calmer you can stay, the more you will suppress your heart rate, decreasing the speed at which your body runs through its oxygen supply.

If you’ve got to move, move slowly and as efficiently as possible, like Sulbin as he lazily swims toward the bottom.  The more you thrash and the harder you work, the faster you’ll convert your oxygen to carbon dioxide.  Free divers seek to improve their performance by finding the most hydrodynamic postures and eliminating every redundant movement. As Ferretti (2001: 256) writes: ‘As a consequence, the improvement in the dive record [depth] took place without significant changes in the duration of the dives, which remained steady at around 3.5 min.’

The good news is, your body is going to help you.  Thanks to evolution, you’ve been born with a mammalian dive reflex that might keep you alive, or help you to stay under water way longer than you might expect.

Dive reflexes, human and mammalian

The remarkable human ability to adapt to free-diving arises, in part, from the body triggering specific nervous system responses, including a reaction to deprivation from oxygen that can be seen in walruses and other aquatic mammals.  Megan Lane explains on the BBC website, quoting freediving instructor Emma Farrell, the author of One Breath, A Reflection on Freediving:

The mammalian dive reflex – seen in aquatic animals such as dolphins and otters, and in humans to a lesser extent – helps, says Farrell.

“It’s a series of automatic adjustments we make when submerged in cold water. It reduces the heart rate and metabolism to slow the rate you use oxygen.”

In fact, the human dive reflex seems to be triggered especially by apnea (the abrupt stop of oxygen intake) and by cold (see Speck and Bruce 1978).  You can make use of the dive reflex, if you ever need to relax, by temporarily putting your face into cold water; your heart rate should drop, which can be a really godsend if you have to do something that’s ramping up your excitability.

The dive response is generally said to be composed of three changes:

1. bradycardia, or a slowing of the overall heart rate;
2. peripheral vasoconstriction, or the shutting of capillaries on the body’s extremities; and
3. shunting of blood into the torso, especially the chest, which helps to resist increased pressure.

In most people, the drop in heart rate from the dive reflex is not as great as in other mammals; while most humans decrease by about 10-25%, some mammals can drop to as little as 10% of their normal heart rate (Speck and Bruce 1978).

The human dive reflex, however, can increase with training (Schagatay et al. 2000).  A trained diver’s heart rate can drop profoundly during a dive.  Some studies have found veteran divers with pulse rates as low as 20-24 beats per minute, especially at the deepest parts of their dives (see Ferretti 2001: 263).

Veteran breath-hold divers, such as pearl divers and marine harvesters, can even demonstrate a more profound cardiac adaptation to diving that can be found in some of the most dedicated competitive free divers, which is not found in other mammals.  Scholander and colleagues (Scholander et al. 1962: 189) found that Australian pearl divers demonstrated cardiac arrhythmias, perhaps a defense against asphyxia developed at birth they theorized. As these divers went deep, the interval between heartbeats sometimes became irregular; in one case, a diver at 30 m depth had one interval of 7.2 seconds.  Extrapolated, this would be the equivalent of a pulse of eight beats per minute!

Scholander and colleagues argue that this arrhythmia is phylogenetically ancient; fish taken from water exhibit similar cardiac responses. The dysrhythmic response, however, together with an increase in blood pressure, make the human dive reflex a bit dissimilar from the mammalian dive reflex found in species like seals and otters.

Vasoconstrition on the periphery of the body and the centralization of blood flow likely increases the efficiency of the body for the duration of the dive (see Ferretti 2001: 262-263).  The less the blood is carrying oxygen out to the peripheral muscles and skin, the more energy (and oxygen) is available to the central organs.

The peripheral body parts end up relying more on anaerobic energy production, leading to a build up of lactic acid.  So even if you’re swimming along dreamily looking to spear a fish, the muscles in your hands and outer extremities will start switching over to the metabolic process you would use during anaerobic exercise, leading to the possibility of cramps and the same kinds of pains you would feel with lactic acid buildup.

Accommodating the pressure

One of the dangers of diving is, of course, the increased pressure.  Every 10 m of depth raises the pressure on the body by one atmosphere, compressing gas to half its previous volume within the body while the body’s tissue largely remains the same volume.

Boyles’ Law holds that gas expands and contracts depending on the pressure, so the descent into high-pressure depths can compress gasses that might later expand dangerously if the body decompresses too quickly.  Since every 10 m halves the volume of a gas, a 30 m dive (to four atmospheres of pressure) would temporarily compress eight liters of air (a ballpark figure for good lung capacity) down to a single liter of volume.

The earliest research on breath-hold diving assumed that the maximum depth of any diving was determined by the residual volume of the lungs. Theorists assumed that, once the pressure crushed the volume of the air in the lungs below the minimum size of the lungs, the lungs would implode.  But as dive records grew deeper and deeper, especially past Bob Croft’s 73m record in 1968, researchers began to suspect that the body was alleviating the danger of the pressure to the thorax through some sort of adaptation.

As Ferretti (2001: 256) reviews, theorists realized that one way the body might respond to the pressure of the dive was to ‘blood shift’ or to shunt blood from the extremeties into the abdomen.  Imagine the arms and legs are like toothpaste tubes and, under pressure, the blood squeezes into the thorax, which helps to keep the chest from collapsing even though the remaining air in the lungs shrinks and shrinks following Doyle’s law.

Subsequent research has found that, in addition to increased blood volume in the chest cavity, the body also responds with an arching of the diaphragmatic dome upwards (so that the abdomen compresses more than the chest), an engorgement of pulmonary blood vessels (those in the lungs), and an increase in the diameter of the heart (Ferretti 2001: 256-257).  In some ways, all of these are not so much ‘adaptations’ as they are simply how the body responds mechanically and hydraulically to the increasing pressure. Fortunately for free divers, their lungs are not in the fingertips or toes, or the increasing pressure would be a much greater problem for anyone trying to dive.

Most people who watch Hollywood thriller also know vaguely about the dangers of ‘the bends,’ when depressurizing overly quick from very deep dives leads compressed gas to bubble up in the joints, causing severe pain.  ‘The bends’ are not so specifically a danger brought about by compression, but rather by the decompression as one ascends from a dive.

In fact, the complications are even more numerous, as decompression can lead to pulmonary barotrauma (burst lung) or tears in the lung tissue that can result in emphysema and air emboli, which can block arteries.  Overly rapid decompression can lead to air bubbles forming within the brain or spinal cord (causing paralysis or sensory impairment) and in other bodily systems.

Some Bajau and other ‘sea gypsies’ do die of decompression side effects; repeated dives to 10 to 20 m depths actually carry a high risk of decompression sickness, according to the Human Planet website. The danger is increased by rudimentary ‘diving equipment’ that allows divers to stay down longer at slightly deeper depths.  For example, compression divers in the Philippines encountered by the Human Planet team were using garden hoses hooked to air compressors to pump down air and extend their time to work underwater.

But even at shallow depths, the pressurization-depressurization of the body can be dangerous.  Already at 10 to 20 m, the compression of the air in the sinuses and then re-expansion can cause damage, especially if the diver can’t successfully equalize the pressure between sinus cavities and ears, for example.  It’s hard to even imagine how the body can withstand the compression and then depressurization on competitive free dives; the world record for a sled-assisted plunge is more than 200 m.

21 atmospheres of pressure on the air in the lungs and sinuses, and then all released on the way back up!

Physical change from pressure: adaptation?

The situation of how human bodies can ‘adapt’ to the pressure of free diving is a more complicated and ambivalent case of human adaptation then just the dive response, however.  ‘Adapting’ to depths can include multiple ways to deal with pressure change; for SCUBA divers, the solution is to develop guidelines for safe diving, use equipment that accurately measures one’s depth, and protocols for decompression, including charts that show safe ascension rates.

For people who forage underwater like Sulbin, ‘adapting’ can instead involve biological and health trade-offs, as Johnny Langenheim reports in The Guardian:

Since diving is an everyday activity, the Bajau deliberately rupture their eardrums at an early age. “You bleed from your ears and nose, and you have to spend a week lying down because of the dizziness,” says Imran Lahassan, of the community of Torosiaje in North Sulawesi, Indonesia. “After that you can dive without pain.” Unsurprisingly, most older Bajau are hard of hearing. When diving, they wear hand-carved wooden goggles with glass lenses, hunting with spear guns fashioned from boat timber, tyre rubber and scrap metal.

In his review of the literature on breath-hold diving, Ferretti (2001: 255) tells a story of a similar adaptation in a European diver:

A remarkable performance was accomplished in 1913 by a Greek fisherman ashore the island of Skarpanthos, in the Aegean Sea: this man was able to rescue the anchor of an Italian ship, which was grounded at a depth of 70 m, by means of three consecutive breath-hold dives with a 15-kg counterweight on his belt. The ship physician reported that this diver suffered of emphysema and had no eardrums (please refer to the medical report in Appendix 1). The fisherman understated his achievement and claimed that he was used diving to 110 m…  [I’ve put the whole medical report below if you’re as fascinated by this as me.]

I keep putting ‘adaptation’ in scare quotes because carrying around ruptured eardrums may not seem like some folks’ idea of ‘adaptation,’ which may imply a less ambivalent form of biological compensation.

The case of ruptured eardrums from diving also highlights the interlacing of phenotypic and cultural adaptation.  The Bajau undergo a phenotypic change (an ‘adaptation’) because they train themselves to go to these depths; without the social support and knowledge, they probably wouldn’t be diving so deep in the first place. Then, when the pain and scary symptoms set in, fellow Bajau like Imran Lahassan tell them how to deal with the damage; lie down, wait, you’ll be fine,… well, a bit hard of hearing.

Of course, ruptured eardrums are damage to the body, like emphysema, but they are also an adaptation, in the sense that they make the body better suited for diving.  From the outside, we may look at the trade-off and say, ‘that’s crazy,’ but we face our own health-related trade-offs as our bodies adapt to the artificial environments we create for ourselves.  A Greek fisherman capable of recovering an anchor 70 m below the surface might look at the trade-offs of sedentary life and say, ‘that’s crazy!  Look at the price their bodies pay for what they do!’

I’ve written about similar adaptations in a book chapter that’s forthcoming for next year, when capoeira practitioners encourage each other to forge on in training through pain until the body adapts, in the case I discuss in the chapter, to putting your head on the ground.  These sorts of biological changes highlight the inseparability of culture and biology, that our bodies are shaped by collective knowledge just as so much of the shared wisdom in practical communities is precisely about how the body functions, its limits, and what sort of adaptive trade-offs are even possible (as well as support structures to encourage and facilitate these changes).

Building a better diver’s body

Over time and repeated dives, the divers’ bodies adapt to diving.  Bavis and colleagues (2007), drawing on research on human adaptation to hypoxia (low oxygen levels, especially at altitude) and on animal models, suggest that the human respiratory system may have ‘plasticity’ at a number of different levels, from autonomic behavioural adaptations (breathing differently), to structural changes that affect lung volume, and even to biochemical shifts, such as changes to red blood cells.  As they put it, adaptation can occur through ‘modifications to the gas exchanger, respiratory pigments, respiratory muscles, and the neural control systems responsible for ventilating the gas exchanger’ (ibid.: 532).

For one thing, in veteran divers, the dive reflex becomes exaggerated: bradycardia increases so that heart rates become abnormally low, and the divers’ responses to hypercapnia (high carbon dioxide levels) become blunted.  Ferretti (2001: 259) reviews findings that trained free divers are able to absorb almost twice as much carbon dioxide into the blood before needing to breathe. According to Ferretti and Costa (2003: 208-209), similar ventilatory responses have been found in synchronized swimmers, underwater hockey players, submarine escape tower trainers, and Royal Navy divers.  Since the increase in carbon dioxide levels is the primary stimulant to breathe, the ability to tolerate higher levels of CO₂ in the blood (hypercapnia) would allow divers to avoid gasping in conditions that would be hard to resist for normal individuals:

the condition of hypercapnia that was maintained during most of the dive, which could even lead to a reversal of pulmonary carbon dioxide transfer, would compel the diver to resist the drive to breathe elicited by the stimulation of central and peripheral chemoreceptors. This opposition would be facilitated by the observed blunted ventilatory response to carbon dioxide. Carbon dioxide sensitivity could be a primary determinant of the breath-hold duration, at least in professional divers. It is noteworthy that also diving mammals, which are frequently exposed to high arterial PO2 and PCO2 values…, are characterised by blunted ventilatory responses to carbon dioxide compared with non-diving mammals of similar size. (Ferretti 2001: 260)

To my knowledge, no studies have been done on the ‘sea gypsies’ of cardio-vascular adaptations or ventilatory response to hypercapnia.  All research on human hypoxia adaptation of which I’m aware focuses on high altitude populations, where the pressure to adapt would be constant and thus — possibly — more pronounced than in breath-hold diving populations, who only dive when they are foraging or working.

But — and this is the caveat  — the actual accomplishments of breath-hold divers like Sulbin, Greek fishermen, pearl diving Polynesians, and the Ama of Korea are pretty startling, with the ability to stay under water and remain active for long periods of time, so the phenotypic adaptations involved may be quite dramatic.

Sometimes intermittent adaptive pressure, especially severe and gradually increasing pressure, can have greater effect than constant but less severe environmental effects. Remember, I’m talking about phenotypic adaptation, not genetic selection over multiple generations.

The BBC website, for example, mentions the possibility of the spleen contracting to squeeze out more haemoglobin, an effect seen in some research on the Ama:

During breath-holding, oxygen stores reduce and the body starts diverting blood from hands and feet to the vital organs.

Our bodies have a way to compensate. Underwater pressure constricts the spleen, squeezing out extra haemoglobin, the protein in red corpuscles that carry oxygen around the body.

“Not enough research has been done to know if it wears off when you’re not diving,” says Farrell. “But I know people who do a lot of deep training – as Sulbin does – whose blood is like that of people living at high altitude.”   In high altitudes, there is less oxygen and so the amount of haemoglobin in blood increases.

This increasing efficiency and trainability (Schagatay et al. 2000) is what makes me a little uncomfortable with referring to the changes as part of a ‘dive reflex,’ in part because I’m not entirely sure that the term ‘reflex’ is universally parsed in the same way.  Clearly, bradycardia and peripheral vasoconstriction are common responses; heck, you can even argue that vasoconstriction is not so much an adaptation as a direct consequence of the mechanical and hydraulic ways that pressure affects the body (in other words, it might be hard to call vasoconstriction an ‘adaptation’ given some definitions of the word – you could call it a ‘consequence’).

A fully blown human ‘dive reflex,’ with profound bradycardia, vasoconstriction, cardiac dysrhythmia, (possibly) splenic contraction, even eardrum rupture, because the complex really requires priming from multiple dives, is rather a phenotypic adaptation, with all the messy complexity that I have suggested is implied in the term.  That is, the dive adaptation builds upon innate reflexes, but it also requires cultural niche construction and social support and results in physiological change.

In other words, my problem with ‘reflex’ as a description of what happens to the body during an oxygen-depriving is not merely semantic.  I think it misrepresents the role of consciousness and experience in the physiological response to a very basic sensation: if you’re not ready and accustomed to hypoxia and pressure, immersion is not going to produce the fully blown ‘reflex,’ in part because your interpretation of the event (‘crap, I need to breathe’) may not allow you to grapple with your body’s involuntary reflexes (such as spasms in the diaphragm).  I daresay it’s quite possible that some conscious interpretations of what is happening (‘crap, I am DROWNING!’) may even completely unravel even the basic ‘dive reflex,’ for example causing the heart rate to spike in spite of the tendency toward bradycardia.

The commentator on the video clip says that Sulbin’s heart rate can drop to 30 beats per minute, and competitive free-divers can achieve even lower rates.  But they do so, in part, by seizing willful control of the autonomic system through proxy variables, specifically emotional states. They don’t just benefit from the ‘dive reflex’; they drive a consciousness-to-emotion-down-to-autonomic chain to get more out of the dive reflex than just the 10-25% reduction in heart rate that most of us would get (if we don’t panic, in which case we might not even get that).

Will Trubridge, for example, like many competitive free divers, uses meditative and mind-body techniques borrowed from yoga.  Sulbin uses his pre-dive routine, including a smoke to ‘relax his chest’ and air gulping.  That is, the ‘reflex’ can be elaborated into a well-schooled top-down technique for self-management that ends up exerting control over autonomic systems like the cardio-pulmonary system.

Loose notes

As I write this, I realize that I’ve got a couple more things to add about this video that I can’t really fit into my central argument, so I’m just going to put them here. Although I’m fascinated by diving and could go on, I just want to quickly highlight a couple of the ways that life and water can lead to human adaptation to a more amphibious existence:

1.  Buoyancy

One of the strangest things about the footage of Sulbin is his apparent negative buoyancy: he walks along the bottom and doesn’t just bob up to the surface.  When most people hold their breath, they are positively buoyant; the air inside the torso offsets the slightly greater-than-water density of bodily tissue so that most people will bob to the surface when they hole their breath.

As you hold your breath, the total air in the lungs does gradually decrease, so you become slightly less buoyant near the end of a breath-hold.  But for most people, the only way to really sink is to exhale a bit to get to negative buoyancy.

Being extremely lean can make the body sufficiently dense that a person is negatively buoyant, even when holding a full breath.  Being lean also helps you to stay under water longer because, if your lung volume remains constant, decreasing your overall weight means more oxygen for every kilo of oxygen-burning bodyweight.  So if you want to hold your breath a long time, it helps to diet.

2. Body temperature

Spending a lot of time in water can play havoc with the human body’s ability to maintain a constant temperature.  The thermal conductivity of water is twenty-five times greater than air (Reilly and Waterhouse 2005: 74), so being dipped in water below body temperature can quickly lead to hypothermia. Without insulated gear, however, Korean divers can spend hours in the water at 10 degrees Celsius in January, conditions under which hypothermia should have been likely.  Hong and Rahn (1967) found, however, that divers did not have thicker layers of subcutaneous fat.  In fact, during the coldest seasons, an elevation in their basal metabolic level—an incredibly rare seasonal variation in human metabolism—left them unable to eat enough to keep from slowly losing weight.  They turned up the internal furnace.

In addition, the divers’ vascular systems appeared to adapt, restricting heat loss from blood vessels near the skin by constricting them (ironically, to below the level of obese individuals).  Their skin became cool to the touch; if the furnace was up, they were also closing off less important rooms in the house.  In addition, the shiver response was suppressed because it speeds up the body’s radiation of heat.  Ferretti and Costa (2003: 208) note that adaptation to cold has also been found in Australian aborigines who sleep nearly naked in the cold; in trained Arctic scuba divers, even when they wore wetsuits (it’s still bloody cold); and in Canadian fishermen who repeatedly immerse their hands in water at 9-10 degrees.  The adoption of wetsuits by the Ama, however, has led to a decrease in their bodily adaptation to cold-water resistance.

3. Underwater vision

In research that’s far too interesting for me to just discuss in passing, Anna Gislén and collaborators (2003) found that children among the Moken, one of the indigenous groups called ‘sea gypsies,’ developed the ability to see nearly twice as well as European children under water.   Because water has a higher density than air, light passing from water into the eye does not refract as much, so our pupils do not redirect it sufficiently to focus the image on the retina (instead, the light converges beyond the back of the eye, where the accurate image cannot be perceived).  Moreover, since our pupils respond to the decreasing light that strikes the eye as we dive deeper by dilating, the lens flattens and exacerbates the distortion still further.

Gislén found that Moken children’s pupils responded in the opposite way when diving, constricting (which the eye would normally do in bright light) so that the lens caused the image to converge on the retina.  Gislén and a team was able to train European kids to do the same thing upon her return (Gislén et al. 2006).  Again, an ‘automatic’ system or reflex could be re-directed through training, whether or not the individuals involved were explicitly aware of what their nervous system was learning to do.

Like I said, way too interesting for a little note, but this will have to suffice for now…

Links:

• The BBC’s Human Planet page on ‘Oceans’
• A beautiful pilot of a documentary project that was posted on YouTube in 2010: Early Pilot for The Moken Kabang Documentary Film in pre-production, spring-2010.
• The Sea Gypsies of Surin Island: The Wake of the Tsunami Brings Both Help and Harm to Thailand’s Mogen People.  By Antonio Graceffo (February 2007)
• Rebecca Leung, Sea Gypsies Saw Signs In The Waves: How Moken People In Asia Saved Themselves From Deadly Tsunami, CBS News, 10 June 2007.
• Johnny Langenheim, The last of the sea nomads, The Guardian 18 September 2010.
• The Sea Gypsies of the Andaman Sea, Sonia Y. Dong, Environmental Graffiti
• Where the sea whistle echoes, video on the Ama, ‘the legendary women divers of Japan,’ from the United Nations University
• The AmaSan Japanese Diving Women, by Jolie Bookspan, M.Ed, PhD, FAWM on HealthLine.com  (there’s a whole series of articles on the Ama and Haenyeo of Korea linked on this site)
• Megan Lane, What freediving does to the body
• James Morgan Photography, provides beautiful photo essay on the Bajau Laut.  If I had more time and patience, I would write to him and beg to reproduce some of his images here.
• William Trubridge freedives THE ARCH at Blue Hole, Dahab, video on YouTube.
  ‘The first no fins, no suit freedive through the Arch, a 30m long tunnel connecting Dahab’s Blue Hole to the Red Sea at a depth of 55m.  William Trubridge is the world record holder in unassisted freediving. Website: www.verticalblue.net’
• AIDA — Association Internationale pour le Développement de l’Apnée – the international association for breath-hold diving.
• United States Apnea Association

Image:

Photo, ‘Freediving: Ewens Ponds’ by Saspotato (no real name given) on Flickr.com, Creative Commons license.

Saspotato also tells us, ‘This photo was taken on March 20, 2010 in Mount Gambier, South Australia, AU, using a Sony DSC-P93A.’

Photo of multiple divers, Robert Berman/HA’a, from Remember the Water

Appendix:

Ferretti (2001: 267-268) provides an English translation of the medical report done on the Greek fisherman who successfully dove 70 m for the lost anchor, and I feel I must reproduce it in its entirety:

Haggi Statti Giorgios, born in Simi, sponge diver, 35-year-old, married, four children, all alive and healthy. He is 1.70 m tall and weighs 65 kg. His resting thoracic perimeter is 0.92 m, being 0.98 m after a maximal inspiration, and 0.90 m after a maximal expiration. Dark-skinned, slim, he has an ordinary muscle mass. Although an examination of the thorax reveals a remarkable lung emphysema, the upper part of the thorax has not yet reached a large size, even if it is somewhat convex and rigid. The heart tones are far, but regular. The pulse rate is 80-90, and the respiratory rate is 20-22. Nothing abnormal in the nervous system, nor in the eyes. He has impaired auditory function because of the complete lack of the eardrum in one ear, and only the remnants of one in the other. He sfufered from no illness, except for a trachoma, healed after surgery. He reports only pain in his back, which he tolerates resignedly. When asked to hold his breath in the ordinary ambient, he first refused, claiming that the test had no value because he could resist much more under water. Then he accepted, and it resulted that his capacity under these conditions is only 40 s. Yet in the rescue operations he dived to depths varying from 40 to 60 m, and even to 80 m, staying under water for 1.30-3.35 min. He claims that he has reached 110 m, and that he can stay at 30 m for up to 7 min. Statti emerged from all dives in good shape and vigour, as demonstrated by the way he jumped into the boat and released the water that had entered his nose and ears. When questioned on the phenomena he feels during the dives, he says he perceives none. Probably accustomed since childhood, he does not perceive them. He only says he feels all pressure on his shoulders. Nothing on his eyes. He also claims that at 80 m, despite the weakening of light, one can see enough to work, if the water is clear.

On a similar note, one of the accounts of Sulbin on the BBC website reports that his abilities do not come from his clean living.  According to their website: “Anyone who thinks this is an example of what a non-smoker’s lungs can do will be disappointed,” says Hugh-Jones. “Sulbin smokes like a chimney. He says it relaxes his chest.”

Like I said: ‘adaptation’ is a pretty neutral word for what can be a far more complicated reality.

References:

Bavis, R., Powell, F., Bradford, A., Hsia, C., Peltonen, J., Soliz, J., Zeis, B., Fergusson, E., Fu, Z., Gassmann, M., Kim, C., Maurer, J., McGuire, M., Miller, B., O’Halloran, K., Paul, R., Reid, S., Rusko, H., Tikkanen, H., & Wilkinson, K. (2007). Respiratory plasticity in response to changes in oxygen supply and demand Integrative and Comparative Biology, 47 (4), 532-551 DOI: 10.1093/icb/icm070

Ferretti, G. (2001). Extreme human breath-hold diving European Journal of Applied Physiology, 84 (4), 254-271 DOI: 10.1007/s004210000377

Fitz-Clarke JR (2006). Adverse events in competitive breath-hold diving. Undersea & hyperbaric medicine : journal of the Undersea and Hyperbaric Medical Society, Inc, 33 (1), 55-62 PMID: 16602257

Ferretti G, & Costa M (2003). Diversity in and adaptation to breath-hold diving in humans. Comparative biochemistry and physiology. Part A, Molecular & integrative physiology, 136 (1), 205-13 PMID: 14527641

Gislén A, Dacke M, Kröger RH, Abrahamsson M, Nilsson DE, & Warrant EJ (2003). Superior underwater vision in a human population of sea gypsies. Current biology : CB, 13 (10), 833-6 PMID: 12747831

Gislén A, Warrant EJ, Dacke M, & Kröger RH (2006). Visual training improves underwater vision in children. Vision research, 46 (20), 3443-50 PMID: 16806388

Hong, Suk Ki, and Hermann Rahn.  1967.  “The Diving Women of Korea and Japan.”  Scientific American 216 (5): 34-43.

Park YS, Shiraki K, Hong SK (1990) Energetics of breath-hold diving in Korean and Japanese professional divers. In: Lin YC, Shida KK eds.  Man in the sea.  Best, San Pedro, Calif., pp 75-87.

Parkes, M. (2005). Breath-holding and its breakpoint Experimental Physiology, 91 (1), 1-15 DOI: 10.1113/expphysiol.2005.031625

Reilly, Thomas, and Jim Waterhouse.  2005.  Sport, Exercise and Environmental Physiology. Edinburgh: Elsevier.

Schagatay E, van Kampen M, Emanuelsson S, & Holm B (2000). Effects of physical and apnea training on apneic time and the diving response in humans. European journal of applied physiology, 82 (3), 161-9 PMID: 10929209

SCHOLANDER PF, HAMMEL HT, LEMESSURIER H, HEMMINGSEN E, & GAREY W (1962). Circulatory adjustment in pearl divers. Journal of applied physiology, 17, 184-90 PMID: 13909130

Speck, D. F. and D. S. Bruce.  (1978) Effects of varying thermal and apneic conditions on the human dive reflex.  Undersea Biomedical Research 5(1): 9-14.

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