Breeding sex ratio higher in Europe than sub-Saharan Africa

Another blow to Peter Frost's goofy-ass theories.
One interpretation of these results is that there is strong evidence for an unequal female and male Ne in at least three of our six populations, with estimates of the breeding sex ratio (i.e., the effective size of females to males) ranging from 2.1 in the San to 12.5 in the Basque.

[Hammer MF, Mendez FL, Cox MP, Woerner AE, Wall JD (2008) Sex-Biased Evolutionary Forces Shape Genomic Patterns of Human Diversity. PLoS Genet 4(9): e1000202. doi:10.1371/journal.pgen.1000202]
Figure 2 shows Nx/Na is higher in Basques than in any of the sampled African populations (Mandenka, Biaka, and San).

36 comments:

David Hook said...

I'm not sure those charts say much.

Only the Basque, Melanesians and Mandenka showed 95% confidence intervals for excess X diversity, and I don't know if their numbers can be compared with high confidence.

On a purely ethnographic basis, we know there is relatively high polygyny among the Melanesians and West Africans (low among San and Biaka), and their Westernized counterparts. Don't know about Basques.

n/a said...

"Those charts" say a hell of a lot more about long-term breeding structure than the decade-plus-old genetic evidence Frost has presented.

Frost claims:

These [sub-Saharan] societies seem to have long been highly polygynous. The ratio of Y chromosome to X chromosome variability is much lower than in other populations, apparently because proportionately fewer men have contributed to the gene pool

Typical of the evidence Frost cites is this paper which looks at a single Y STR and two X STR loci.

In contrast, the authors of the paper I cite "analyzed ~210 kb of DNA sequencing data representing 40 independent noncoding regions on the autosomes and X chromosome from each of 90 humans from six geographically diverse populations."

If you are pathetic Frost fanboy "tod"/"roy", pick a single name and stick to it or don't post here.

n/a said...

Incidentally, if you picked a 99% C.I., Basque but not Mandenka would show excess X diversity.

And the issue is not whether these particular results prove with high confidence that Nx/Na is higher in Basque than Madenka, but that they definitely don't show the opposite, which sort of kills Frost's theory.

Peter Frost said...

I'm not surprised by the relatively high X chromosome diversity for the Mandenka and the Melanesians, given their high incidence of polygyny. Nor am I surprised by the relatively low values for the San and the Biaka, both of whom are hunter-gatherers. Polygyny is high among sub-Saharan agricultural peoples because year-round agriculture makes women less dependent on men for food provisioning. The costs of taking a second wife are thus correspondingly lower.

But, yes, I am very surprised by the high values for the Basques and the Han Chinese, both of whom have polygyny rates well below the 10% level.

My main quarrel with the Hammer et al. paper is that it compares X-chromosome variability only with autosomal variability. The Y chromosome is no longer a point of reference. This methodology has some advantages, but it seems (to me at least) more vulnerable to the effects of patrilocality.

In societies that have high paternal investment, residence tends to be patrilocal, i.e., the bride moves in to her husband's community. This has the effect of increasing maternal genetic diversity in any one community.

There is no easy way to eliminate the effects of patrilocality entirely. But at least if you examine the Y chromosome, you can tell whether or not there has been an absolute (and not relative) decrease in paternal genetic diversity.

n/a said...

This methodology has some advantages, but it seems (to me at least) more vulnerable to the effects of patrilocality.

Huh? Why? Because it would be convenient for you if that were true?

In societies that have high paternal investment, residence tends to be patrilocal, i.e., the bride moves in to her husband's community. This has the effect of increasing maternal genetic diversity in any one community.

Sub-Saharan agriculturalists "practice a rigid patrilocality". "Truth" is not a synonym for "what, if true, would be convenient for Peter", and you have presented no evidence to support the idea that genetic structure created by patrilocality would distort results from samples of modern Chinese and Europeans more than tribal, food-producer Africans.

But at least if you examine the Y chromosome, you can tell whether or not there has been an absolute (and not relative) decrease in paternal genetic diversity.

Nonsense. What is "absolute paternal genetic diversity"? Diversity (in this context) is always relative.

Y DNA is more sensitive to genetic drift, and probably reflects more recent demographic trends. It's entirely appropriate to look at autosomal DNA when investigating long-term breeding structure.

You don't seem to understand how science works. You need to fit theory to data, not the other way around. And if you want to rationalize away data that doesn't fit your theory, you need to make sure the rationalizations actually make sense.

Peter Frost said...

N/a,

With the methodology used by Hammer et al., it is impossible to tell whether the increased diversity of maternal genetic lineages is due to polygyny or patrilocality. Are these lineages more diverse because proportionately more women have contributed to the gene pool? Or is it because the women themselves have been genetically more diverse?

I find it ironic that you cite the article by Destro-Bisol et al. “Variation of Female and Male Lineages in Sub-Saharan Populations: the Importance of Sociocultural Factors”. In that article, the authors attribute the higher genetic diversity of maternal lineages to both polygyny and patrilocality. It is difficult to tease apart these two factors even with the old methodology of comparing Y-chromosome diversity with mtDNA diversity.

By “an absolute decrease in paternal genetic diversity”, I mean that there has been an absolute decrease in the number of men contributing to the gene pool, i.e., polygyny. This may be seen by looking at genetic diversity on the Y chromosome. Hammer et al. excluded the Y chromosome from their analysis. They simply compared X-chromosome diversity with autosomal diversity. This methodology biases the results towards patrilocality effects.

For what it’s worth, it is false to say that sub-Saharan agriculturalists practise ‘rigid patrilocality’. This is the rule only in cattle-based pastoral societies. There are many matrilocal societies among sub-Saharan agricultural peoples, even among the pastoralist ones:

“Among the cattle-rich societies such as the Tswana of eastern Botswana and South Africa, bride-price is uniformly high, and inheritance and descent are reckoned along patrilineal lines. Residence is normally patrilocal. Those who cannot afford to pay with cattle or other valuable goods generally perform bride service – and reside matrilocally (with the wife’s family) for an agreed-upon period of time. In parts of Zimbabwe where cattle are fewer, such as among the Tawara and Zezuru, most marriages were of the second type, with prolonged matrilocal residence. In central Zambia, where inheritable wealth is almost nonexistent, matrilineal descent with bride service and matrilocal or avunculocal residence were most common” Encyclopaedia Britannica – Southern Africa p. 849. volume 27, 15th edition.

Again, this point is tangential to our discussion. The main point is that polygyny and patrilocality are both explanations for maternal genetic diversity. Hammer et al. use a methodology that is biased toward patrilocality effects because it excludes the Y chromosome from analysis.

On a final note, I am puzzled by the strident tone of your post. Are you saying that the Hammer et al. paper proves that the incidence of polygyny has been no higher among sub-Saharan agricultural peoples than among the Basques or Han Chinese? The tone of your language suggests we are not simply debating an issue of methodology here.

n/a said...

Peter,

You have simply restated your previous assertions without providing any supporting logic or evidence.

I never argued that patrilocality is not a potential confounding factor.

I pointed out that you gave us no reason to think it should be more of an issue for Basque and Han than for Mandenka, or more of a problem when looking at autosomal instead of Y DNA. You still haven't.

The data suggest that, over the long term, compared to Mandenka, a smaller proportion of Basque men contributed their genes to future generations. Period.

The tone of the post reflects the amount of respect I've come to have for your ideas.

Peter Frost said...

To the extent that Hammer et al.’s methodology is more biased toward patrilocality effects, any polygyny effects will be that much harder to detect. If their methodology primarily tracks differences in patrilocality, I would not expect to see major differences among Basque, Han, and Mandenka subjects.

In addition, there may be a weak inverse relationship between patrilocality and polygyny. Patrilocality correlates with patriarchy, which correlates with high paternal investment, which inversely correlates with polygyny. If so, the two effects – polygyny and patrilocality – would tend to cancel each other out in the data.

Finally, the burden of proof is on those who propose new methodologies, especially if the new methodology produces results that are inconsistent with the existing literature. The authors themselves say as much: “Our findings of high levels of diversity on the X chromosome relative to the autosomes are in marked contrast to results of previous studies in a wide range of species including humans.” More importantly, their findings run counter to the comparative literature on human mating systems. To cite only one authority, Pebley and Mbugua (1989) note:

“In non-African societies in which polygyny is, or was, socially permissible, only a relatively small fraction of the population is in polygynous marriages. Chamie's (1986) analysis of data for Arab Muslim countries between the 1950s and 1980s shows that only 5 to 12 percent of men in these countries have more than one wife. … Smith and Kunz (1976) report that less than 10 percent of nineteenth-century American Mormon husbands were polygynists. By contrast, throughout most of southern West Africa and western Central Africa, as many as 20 to 50 percent of married men have more than one wife … The frequency is somewhat lower in East and South Africa, although 15 to 30 percent of husbands are reported to be polygynists in Kenya and Tanzania.”

I will let other readers decide who has acted disrespectfully in this discussion. Unlike certain people, I do not hide behind a pseudonym. If I have acted improperly, my name and reputation will suffer accordingly.

Reference:

Pebley, A. R., & Mbugua, W. (1989). Polygyny and Fertility in Sub-Saharan Africa. In R. J. Lesthaeghe (ed.), Reproduction and Social Organization in Sub-Saharan Africa, Berkeley: University of California Press, pp. 338-364.

n/a said...

There is absolutely no reason to think "that Hammer et al.’s methodology is more biased toward patrilocality effects". You have explained why you wish it were true. (Though it was already obvious.) You have repeatedly failed to explain why anyone besides you should think it is true.

"In addition, there may be a weak inverse relationship between patrilocality and polygyny."

"May". An improvement over simply asserting it is true because it would help your argument.

Anyway, we're concerned here with specific cases (e.g. Basque and Mandenka), not supposed, "weak", untested general trends.

And I notice you don't seem at all concerned about "patrilocality effects" when African hunter-gatherers and agriculturalists are being compared and the genetic evidence falls in a direction you like.

More importantly, their findings run counter to the comparative literature on human mating systems.

More circular argumentation. Polygyny today is not the issue. At issue is your projecting current practices into distant prehistory (and/or engaging in outright speculation, as you do with ancient Europe). You approvingly cite what you believe to be favorable genetic evidence to support your theory while discounting genetic evidence which doesn't support your theory -- because it doesn't support your theory.

Incidentally, I missed this the first time I looked at the article:

Nonetheless, application of our methods to genes in the NIEHS study with recombination rates similar to those for our intergenic regions (i.e., r>0.9 cM/Mb) yields estimates of Nx / Na ranging from 0.87 in the Yoruba to 1.08 in the CEPH (results not shown), similar to the point estimates shown in Figure 2.

That is, another, independent, dataset shows Europeans (NW European Americans, in this case) have higher Nx / Na than sub-Saharan agriculturalists (Yorubans).

I will let other readers decide who has acted disrespectfully in this discussion.

I'm beginning to suspect you're not intentionally arguing in bad faith -- you're just mentally disabled. I tell you I don't respect you, and you respond as though I was arguing something else entirely.

Lest there be any confusion: you earned my disrespect through repeated demonstrations of apparent bad faith, shoddy reasoning, and atrocious reading comprehension. In this thread, you have reconfirmed my earlier estimation.

Wig-master said...

Pictures are worth a thousand words

n/a said...

todroy,

Typo: pretty sure you meant to sign as "fag-master".

Tod said...

I admit that (like most people) I don't know enough about interpreting studies like Rohrmann et al. to really understand the points you made in defending it. Maybe you have got a PhD but don't expect anyone will assume so if your arguing against someone who does. This site has a link to John "Population mixing...is evolution" Hawks
(Yes he says this here Don't hold your breath waiting for him to come to your comments section to be told the error of his ways. (he doesn't allow comments at his own blog).
Whats with the insults?
I think the pictures show a surprisingly powerful build in a certain hoe farming population.

n/a said...

Tod,

Your obsession with promoting the idea of hypermasculine negroes (and now Melanesians) comes off as very gay. That's not an insult, that's the truth.

But your real problem is the comically inept reasoning and choice of evidence you employ chasing after your favorite theme--plus your fawning attitude toward your preferred authority.

Note that John Hawks has a PhD. So did Franz Boas, Ashley Montagu, Richard Lewontin, and so on. A PhD is no basis on which to uncritically ally yourself with someone's ideas.

Nor does your personal impression of a photograph substitute for anthropometric data on representative samples. Nor, even if the anthropometric data flowed in a direction you found agreeable, would you have made your case.

The first data point I find puts the average BMI of 142 males from Kitavan at 20. Shockingly powerfully builds, indeed.

John "Population mixing...is evolution" Hawks

It is. When the dumb and fat out-reproduce the intelligent and attractive, that's also evolution. Calling something evolution does not mean it is desirable.

Tod said...

OK my bad mistake, the offending remarks were not thought through. I was new to commenting and got carried away.

Direct comparisons like I was making on skin colour and finger ratio don't hold true across the races or boil down to a single measure that can be applied to all of them in the same way.
So I wouldn't try to say that the whiter skin of Europeans or higher finger ratio (if it is) means a lesser physique in Europeans than the Kitava,Trobriand Islanders
The data showing a weak build in the Trobriand Islands should not be taken as a refuting darker skin as an indicating selection for competition between males for women entirely. I think that within a region such as Melanesia it remains valid. Consider this "It is a sensual tropical paradise where the women rule and the men trade kula rings. The Trobriand Islands, or Islands of Love, off the coast of Papua New Guinea are home to a matrilineal society, which passes land and inheritance through the female side of the family. Spiritual traditions and fertility rites focus on cultivation of the phallic yam, and Trobriand Islanders are said to condone sex between unmarried teen-agers, extramarital sex with multiple partners, and even the conquest of men by married women. Mungo Park ™online adventure magazine, published by the Microsoft® Expedia ™ travel service (http://mungopark.com) , will conduct the first-ever online expedition to the Islands of Love with guest correspondent Dr. Ruth Westheimer Oct. 10-21.

The Trobriand Islands, a seldom-visited archipelago of 160 islands, are one of the planet's last frontiers and remain relatively untouched by Western influence. Culturally distinct from the rest of Papua New Guinea due to their matrilineal society, the inhabitants possess a form of modesty that Westerners find curious. For example, it is taboo for an unmarried man and woman to share a meal together, although premarital sex is accepted behavior".

Compare Bouganville Island "The presence of Bougainville as a 'black spot' in an island world of brownskins (later called redskins) raises a question that cannot now be answered. Were the genes producing that darker pigmentation carried by the first Bougainvillain s when they arrived? Or did they evolve, by natural or by 'social' selection, during the millennia in which the descendants of those pioneers remained isolated, reproductively, from neighbouring islanders? Nothing now known about Bougainville;s physical environment can support an argument for the natural selection of its peoples' distinctively black pigmentation; therefore a case might be made for social selection, namely, an aesthetic (and hence reproductive) preference for black skin. This preference has, by the way, surfaced recently with added political meaning". or this " Many women from Bougainville went through bad experiences similar to those faced by my family.

Our women felt the most pain, trauma and loss because of their place in society. Many were tortured, pack raped and even killed. We were terrorised for speaking out for the rights of our families.

We witnessed our sons and husbands being killed and treated like animals, by all sides in the conflict. We were accused of hiding and refusing to let sons and husbands join the authority of the day. Yet despite the atrocities, we continued to pull our families together as the basic unit of community support. We organised ourselves into church groups and community organisations.

It was in this context that LNWDA was formed in 1992 (formally launched in 1995) by myself, Agnes Titus, Brenda Tohiana and Alina Longa, with the goal of creating a world safe for women and children. Our motto was 'Women Weaving Bougainville together'. We just couldn't stay and watch our sisters die in childbirth, raped, sexually harassed and emotionally abused". The blackest population show signs of selection for competitive among men for access to women, they are violent and competitive compared to the paler Trobriand islanders. "Women everywhere in Bougainville suffered the same. Nobody ever thought that there would be a civil war. Nobody ever thought that we would die at the hands of our own people". here

True what you say about evolution however is that what John Hawks was meaning? I get the impression he was (not very scientific of him) talking about improvement though mixing.

If I had a blog like this someone like John Hawks would be welcome in the comments section they could only add value, if there was disagreement I wouldn't personalize it. Just blogging can hurt an academic's career acording to Hawks, even critical commenting at this site is going to be frowned upon. Lewontin's Fallacy ? True enough it doesn't take a PhD to see Lewontin is wrong but this refutation of his arguments has a certain credibility that would be lacking otherwise.

n/a said...

Frankly, I'm not that interested in Melanesians. The point is, if you are genuinely seeking understanding, you need hard data, not anecdote or subjective impressions.

Your theories should come with predictions, and when those predictions turn out to be wrong, you need to reexamine your theory. Instead, you and Frost have a nasty habit of trying to simply rationalize away inconvenient data. (I'm speaking in general terms; I have no interest in further discussing Melanesians.)

I get the impression he was (not very scientific of him) talking about improvement though mixing.

Your impression is wrong. Whatever Hawks' politics, he's not retarded; he's clearly competent and knowledgeable on evolution and related subjects. And while we're questioning people's politics, maybe you'd like to explain yours.

If I had a blog like this someone like John Hawks would be welcome in the comments section

If you are likening yourself to Hawks, you need a serious ego check.

Tod said...

The offending comments were ex hypothesi from my reading of John Mannings theories which I tried to apply across races.The low finger ratio of Chinese along with
A frequent Y-chromosome b2/b3 subdeletion shows strong association with male infertility in Han-Chinese population.(Wu et al)
"Our data showed a higher frequency of deletion events in this Han-Chinese population than in populations elsewhere in the world"

shows this does not hold true, as you have pointed out.

Rather than (meaning to) compare myself to Associate Professor J. Hawks, I was trying to compare the treatment he might get from a blog such as this one in the unlikely event that he was to come here and disagree with the blogger in defending his ideas.

I was pointing out the rarity value of relevantly formally qualified people who are willing to come to a site with a racial perspective under their own name and engage in debate. Their politics may be unsound but I wonder about the advisability of turning the heavy artillery on such commenters even if they are wrong on the technical point at issue, (and your opinion of the point at issue in Rohrmann has been supported )

Tod said...

Questioning Dr. Hawks' personal, political or scientific integrity? Far from it, I'm simply noting that very, very, few with qualifications comparable to his even come to a blog such as yours. (As he says, even politically uncontroversial blogging, and presumably commenting activity is frowned upon by people with an influence over careers).
The idea that sexual selection would have a particular focus in tropical garden agriculture is not so eccentric In Our Genes by Harpending and Cochran suggests something similar.

n/a said...

I've emailed Hawks several times when I thought he made unjustified claims. His response to criticism contrasts starkly with Frost's. Hawks is trying to do science. Frost is trying to prop up his pet theories.

Frost does at least go through the motions of addressing criticism, which it's true is more than can be said for many academics. Like you, my first instinct was to give Frost some respect for, if nothing else, a willingness to address racial differences and comment under his own name. But I have little patience in the face of Frost's unwillingness or inability to argue in good faith.

Tod said...

"trying to prop up ... pet theories".

Scientists who are disinterested seekers after truth, unconcerned whether theories they've invested in are right or wrong - are there any?

I'll be very surprised if the starkly contrasting response contained an admission by the Prof. that he was wrong. Lots of now what is now scientific orthodoxy was seemingly contradicted by some of what was known at the time so sticking to your guns is not a bad strategy. Anything else...well it's asking a lot

n/a said...

I don't require perfection. I do expect at least the attempt at objectivity from someone claiming to be a scientist.

If Frost "stuck to his guns" while acknowledging weaknesses in the data or pursuing further research (instead of simply asserting as true what he'd like to be true), he would have retained some level of respect from me.

Tod said...

O.K. I have no qualifications or claim to your respect so I can't retain it (or lose it). I would like to revisit the T. debate, it is central to theories like John Manning's concerning sub Saharan polygny.

Commenting on the Rohrmann study's adjustment for smoking N/A said:-

"It's entirely appropriate to control for confounds like smoking:

Smoking men had significantly higher levels of total and free testosterone compared with men who never smoked (p < 0.001 and <0.01 respectively). Both total and free testosterone levels increased significantly with increasing number of cigarettes smoked daily (p < 0.001). Smoking men had 15% higher total and 13% higher free testosterone levels compared with men who never smoked. Thus, smoking seems to be an important confounding factor when evaluating testosterone levels, and could possibly mask borderline hypogonadism".


Lots of people want to boost testosterone levels. I have never heard of a bodybuilding guru suggesting smoking to raise T., never, they have recomended some risky things but not that. Anything as common as smoking that did produce a really effective increase in T. would be well known by now. People are making a fortune selling herbal formulas, zinc concoctions ect. that claim to do this. The latest study on the subject does not support the idea that smoking increases testosterone (it does increase prolactin)
Effects of Cigarette Smoking

"Our study showed that urinary testosterone was lower in cigarette smokers compared to the non-cigarette smokers (Fig.1) in subjects that are age-matched and of similar body mass index (Table 1).This agrees with previous studies8,15,16. Though there are many chemicals in cigarette smoke, we contend that nicotine, a major constituent of tobacco, could be responsible for the observed reduced testosterone production among the cigarette smokers".
Here is support for the contention that the influence of testosterone disposes one to smoke

prenatal exposure to testosterone boosts smoking
"The frozen blood samples, which tests showed remained in good condition for more than 30 years, revealed both testosterone during pregnancy and levels of cotinine, a byproduct of nicotine indicative of how much a person smokes. Kandel and Udry found no correlation between prenatal cotinine levels in mothers and daughters’ later smoking. They did uncover a distinct correlation, however, between mothers’ testosterone and daughters’ smoking"
Effects of Intravenous Cocaine and Cigarette Smoking on Luteinizing Hormone, Testosterone, and Prolactin in Men

"Testosterone levels did not change significantly after either cocaine or after high nicotine cigarette smoking. After i.v. cocaine, prolactin decreased significantly and remained below baseline levels throughout the sampling period

In another comment N/A points out

"But negroids show less sexual dimorphism than Europeans. In the U.S., black men tend to be slightly shorter than white men, and black women are as tall as or slightly taller than white women".
In
Book Review
Digit Ratio: A Pointer to Fertility, Behavior
Michael mills remarks
"One of the especially interesting theoretical discussions in Manning’s book is his speculation (starting on page 54) regarding why there is any overlap between the sexes in sexually dimorphic traits in the first place, including digit ratio. If being taller than women is adaptive for men in general, why aren’t all men taller than all women? And why don’t all men have a lower digit ratio than all women? Why the overlap? Manning interprets this as an evolutionary stable equilibrium point in a conflict between sexually antagonistic genes. Genes that tend to masculinize the fetus will increase when there is an advantage to having male offspring (e.g., when the operational sex ratio favors men, or there is a polygynous mating system). The benefits of more masculinized male fetuses (increased adult sperm count, higher libido, inclination toward sexual promiscuity, etc.) will compensate for the reduced fertility of female offspring due to their relatively higher than normal fetal exposure to male hormones. When the mating system pendulum swings to the other side, and a monogamous mating system is in place, or operational sex ratio favors females, genes that tend to feminize the fetus will be favored. The result is an overlap in male/female distributions for many sexually dimorphic traits – a somewhat middle ground as parents hedge their bets regarding the relative reproductive potential of male or female offspring. ...we can see that there is far more overlap between the sexes in digit ratio than there is in the overlap between the sexes in height, as noted in the following diagrams.
black men tend to be slightly shorter than white men, and black women are as tall as or slightly taller than white women I consider this significant, why are black women (relatively) slightly taller-if not absolutely taller.
You seem happy to allow that there are significant differences between North and South Europe, whereas the differences between to populations of radically different continents are too small to be bothered about- if they exist. This is baffling to me.

n/a said...

I'm not wedded to the idea that smoking increases testosterone levels. I can find studies showing both higher and lower testosterone levels in cigarette smokers.

Your study showing lower testosterone levels in smoking Nigerians, however, does not support Frost's position. Frost claimed (based entirely on his perception of the testosterone levels of boys he went to high school with, it was later revealed, perfectly illustrating Frost's brand of "science") that (innately) high testosterone levels cause men to smoke and therefore smoking shouldn't be controlled for in a study comparing testosterone levels across race. It's a relatively minor point anyway since smoking was one of several variables controlled for and we have no idea to what degree or even in which direction controlling for smoking affected the numbers in that study.

That said, I notice that the smokers have BMIs about 1.3 units lower than the non-smokers, which the authors consider "similar". Maybe that's similar enough not to affect the outcome, maybe not.

My own wild ass guess is that smoking tends to lower the body's absolute ability to produce testosterone, but under some circumstances, due either to psychological effects or due to some environmental variable that underlies both smoking and situational increase in testosterone, smokers will sometimes be observed to have higher circulating testosterone levels than non-smokers.

Here is support for the contention that the influence of testosterone disposes one to smoke

We're talking about circulating testosterone, not prenatal testosterone. And we're talking about men, not women.

You seem happy to allow that there are significant differences between North and South Europe, whereas the differences between to populations of radically different continents are too small to be bothered about- if they exist.

I follow the data.

The IQ difference between Northern Europeans and Southern Europeans is much smaller than that between N. Euros and sub-Saharans.

The height difference between N. Euros and S. Euros is larger than the height difference between white Americans and American blacks.

The only autopsy weighing study comparing blacks and whites found whites have larger testes; large studies tend to find small or non-existent black-white testosterone differences; and circulating testosterone levels are influenced by environmental factors. So, no, I'm not inclined to believe sub-Saharans have naturally hugely elevated testosterone levels which require some deep evolutionary explanation.

Tod said...

If being taller than women is adaptive for men in general, why aren’t all men taller than all women

According to Robin Dunbar "Tall women are more likely to have uneven features: “Tall men tend to be more symmetrical and have better chances of reproductive success, whereas it is short women who tend to be more symmetrical, to get married and to have children.” "

Now if the women in a population are slightly taller (relative to the men) than we would expect from a comparison to other populations what does that say about the focus of any sexual selection, (and where it was relaxed). Bearing in mind that Black Africans have been theorised to have evolved from much shorter ancestors it would seem that if this is so the increase in height has benefited the reproductive fitness of men at the expense of that of women. The difference in height between men and women (the sexually dimorphic nature of height) should be maintained by a tendency for the taller women to have their average fertility reduced. However this has not been so, as you say
" black men tend to be slightly shorter than white men, and black women are as tall as or slightly taller than white women "
Is this not what would be expected if polygyny had resulted in sexual selection for men while relaxing selection for women. Differences between populations, even very slight average differences, can still be significant. (I understand that you think dim people go overboard and apply such theories to individuals as if there is no overlap)
The honour culture explaination for T. variation makes perfect sense as an explaination for the above average variation in a longitudinal study. My problem is with this
" we believe that around puberty, the effect of T on behavior works primarily through long-term reorganization of the body, including increased size, muscle mass, and the appearance of secondary sexual characteristics. (This physical transition from boy to young man probably builds upon structures laid down perinatally.) Maturation produces profound social effects on the adolescent. His peers, parents, and other authorities all treat him differently because he has "suddenly" grown up. Thus, T affects adolescent behavior mostly through indirect social responses, elicited by maturation, rather than through direct activation of target receptors by T in the bloodstream. This is a provisional conclusion because much remains to be learned, but studies to date give little consistent indication that circulating T level per se affects behavior as much as the overall masculinization of the body during the teen years".
It's all down to how they are treated so adolescent behaviour is not really infuenced by testosterone? Sorry! What!?

There is some support for the roots of the Southern honour culture being being in Scotland (which tops list of world's most violent countries)
But for every winner there are going to be losers who will be forced to back down so a longetudinal study in would find chronically depressed T. levels in persistent losers. And contact sports success is corrolated with strength which is influenced by T. If you look like your reputation for being very strong and tough yes you can get a T. boost from being in a honour subculture but your T. was above average to start (muscles=High T.) If you look weak your going to be victimised or subordinated with chronically lower T.

n/a said...

You're doing it again, trying to force the data to fit your preferred narrative, not seeking the most parsimonious explanation for all the data. Polygyny correlates with increased body size dimorphism across primate taxa, like the comment at Frost's blog to which I was responding said, meaning your logic appears off.

Small differences in sexual height dimorphism among human populations may be informative about any number of evolutionary or environmental variables. You are not justified in assuming such differences represent some sort of clean signal of relative rates of polygyny.

The remainder of your comment contains little of relevance to any argument I'm concerned with. Mazur believes:

Of course, T is also affected by the outcome of the contest, so persistent losers might be hormonally depressed, but most men -- those with mixed outcomes or better -- should have elevated T.

Mazur's hypothesis may explain most or all of the black-white T difference observed in the U.S. If the "honor subculture" produces a net rise in T among its members, who the "winners" are inside it is irrelevant to this argument.

Tod said...

Polygyny correlates with increased body size dimorphism across primate taxa, like the comment .. which I was responding said, meaning your logic appears off. Maybe so and in the context of polygyny greater height difference between the sexes in Europeans is a good point.

However the possibility the increased difference was not produced by men getting taller but women getting shorter exists.
short women ... tend to be more symmetrical, to get married and to have children.
Consider the focus of sexual selection that is theorised to have been responsible for the evolution of Europeans. I will admit the height issue is inconclusive.

It is my impression that compared to the average of humanity Europeans have characteristics that bespeak of sexual selection having a special focus in their evolution. Or at least I think that is more likely than the alternative explainations I have seen.

Mazurur - We share doubts expressed by Archer (1991) and Albert et al. (1994) that circulating T directly affects human aggression -- the intentional infliction of physical injury. We favor instead the hypothesis that high or rising T encourages dominant behavior intended to achieve or maintain high status (implying power, influence, and valued prerogatives). Usually humans express dominance nonaggressively

Not in Honour subcultures they don't, these are defined by the affronted's resort to violence. Mazur's staring duel is a case in point from reading the Code of the Streets should have made it clear to him how this behavior would result in violence in a honour subculture

"Many of the forms that dissing can take might seem petty to middle-class people (maintaining eye contact for too long, for example), but to those invested in the street code, these actions become serious indications of the other person's intentions. Consequently, such people become very sensitive to advances and slights, which could well serve as warnings of imminent physical confrontation."

"Never stare at another prisoner for more than a second or two. He may be a walking powder keg, set off by an intrusive stare. He may either assault you on the spot or wait until darkness. Even if he doesn't kill you outright, your face will never look the same again" (from Basic Survival Techniques for Incarceration)

Mazur thinks T. is irrelevant to violence:-
Rodents typically dominate aggressively, but that is not true among the higher primates (Mazur 1973).

n/a said...

If it wasn't clear from my last post, I don't believe small differences in sexual stature dimorphism among populations say much about polygyny. At minimum, one would need to control for many other evolutionary and environmental variables before trying to discern a signal from polygyny.

As for Mazur, read the whole thing -- not just the first paragraph.

The distinction between aggression and dominance is particularly important for humans, because we often assert our dominance without any intent to cause physical injury. It may be the case that T is related primarily to dominance among men and not to aggression except in situations where dominance happens to be asserted aggressively. Ehrenkranz et al. (1974) showed that socially dominant but unaggressive prisoners had relatively high T, not significantly different from the T levels of aggressive prisoners (who may have been dominant too). Nearly all primate studies that have been interpreted as linking T to aggression (Dixson 1980) may as easily be interpreted as liking T with dominance (Mazur 1976). Recent reviewers have questioned whether, among humans, T is related to aggressiveness per se (Archer 1991; Albert et al. 1994).

[. . .]

We share doubts expressed by Archer (1991) and Albert et al. (1994) that circulating T directly affects human aggression -- the intentional infliction of physical injury. We favor instead the hypothesis that high or rising T encourages dominant behavior intended to achieve or maintain high status (implying power, influence, and valued prerogatives). Usually humans express dominance nonaggressively. We leave as an important but subsidiary question why men sometimes dominate with intent to harm.

Tod said...

Commentary on Mazur :- Mazur & Booth present an intriguing model of the relationship between circulating testosterone levels and dominance behaviour in man, but their review of studies on testosterone–behaviour relationships in man is selective. Much of the evidence they cite is correlational in nature. Placebo-controlled manipulations of testosterone levels are required
to test their hypothesis that dominance levels are testosterone dependent in man. The changes in testosterone level that follow behavioural experience may be a consequence of stress. Testosterone levels in man are determined by a wide variety of factors, and a multivariate approach is required.Mazur & Booth (M&B) propose a reciprocity between testosterone
(T) and dominance behaviour in man. The emphasis on “bidirectionality” (Hatch 1981) is to be applauded. However, their review of the literature is highly selective. They refer extensively to positive findings that do not appear to have been subject to the normal peer-review process necessary for publication in scientific journals (e.g., Booth & Dabbs 1995; Dabbs & Hargrove, in press;Fielden et al. 1994; Mazur & Michalek 1995; Mazur et al., in press), and they neglect to cite published negative findings..../...M&B propose in section 1 that it would be “naively behavioristic”to deny our ability to read people’s intentions. However, particularly in relation to aggressive behaviour, we must acknowledge that people often misperceive the social signals and intentions of others (Navaco 1986). Aggressive men often misperceive.For example, an innocent glance may be construed as a challenging
gaze (inferred malevolence where none exists), thus leading to
challenges and overt aggression
".( picking up on the same thing I did about the staring duel being likely to end in violence )

Guns, Testosterone, and Aggression: An Experimental Test of a Mediational Hypothesis "We tested whether interacting with a gun increased testosterone levels and later aggressive behavior. Thirty male college students provided a saliva sample (for testosterone assay), interacted with either a gun or a children's toy for 15 min, and then provided another saliva sample. Next, subjects added as much hot sauce as they wanted to a cup of water they believed another subject would have to drink. Males who interacted with the gun showed significantly greater increases in testosterone and added more hot sauce to the water than did those who interacted with the children's toy. Moreover, increases in testosterone partially mediated the effects of interacting

Do you think men fron areas high in gun ownership would average higher T.?
Maybe they would, but that is a long way from being able to say they are higher in T. as a result of gun ownership.

Testosterone, cognition, and social status

"Research with humans and a wide variety of animal
species suggests that individuals higher in baseline T are (1)
more driven to gain and maintain status; and (2) moreresponsive to information about their status in a situation.Behaviors intended to achieve, maintain, and enhance statusare observed primarily among high-T animals.../...Derived from the biosocial theory ofstatus (Mazur, 1985), researchers such as Mazur and Booth(1998) are proponents of a reciprocal model of T and status According to this model, experiences of winning and losing status battles can alter T levels, which then predict
subsequent status seeking behavior. For example, in a study
of male tennis players (Booth et al., 1989), participants’ T
levels rose after winning a tennis match whereas losers experienced a drop in T. This change in T carried over to subsequent matches, such that winners who showed an increase in T after winning began their subsequent matches with higher T. Similar findings have been seen in nonphysical domains such as chess, albeit with mixed results
(Mazur et al., 1992).
These reciprocal studies differ significantly from most
basal studies primarily because participants are aware that
they will be competing in a dominance battle right before
their T is assessed. Because the initial measurements of T
are taken in anticipation of a competition, they are not
indicative of basal T. Furthermore, the participants in manyof these studies presumably have knowledge of their relative
ability prior to these competitions, making pre-match risesand declines in T difficult to interpret. Thus, although this research answers important questions about how changes in
the social situation influence changes in T, it does not speak
to the influence of basal T on performance.
"

Average differences between populations including T. are not huge (as you have said). It is still reasonable for inferences to be drawn from them.

n/a said...
This comment has been removed by a blog administrator.
n/a said...

Incidentally, the latest NHANES has black women shorter than white women, by more than black men are shorter than white men.

http://isteve.blogspot.com/2008/12/height-and-weight.html

Tod said...

Baker in Race (1974) cites David Livingstone remarking that intelligent men among the Africans had told him that their own beliefs on what was improper behavior were in agreement with his own with one exception: polygyny.

Polygynists and their wives in sub-Saharan Africa: an analysis of five Demographic and Health Surveys
Data came from 1993-96 Demographic and Health Surveys (DHS) from Ghana, Kenya, Senegal, Uganda, and Zambia. Polygyny is most common in western Africa; however, it is in decline, especially in Kenya. Prevalence is low in urban areas. Polygyny is very common in Senegal, high in Uganda and Ghana, and fairly common in Kenya and Zambia.[...] Prevalence is affected more by socioeconomic and other characteristics than by intensity. Grouping first and higher order wives separately is key. In all countries, divorcees and widows who married single men were unlikely to engage in polygyny. Only in Senegal did polygyny accelerate at higher marital durations.

n/a said...

Relevance?

Peter Frost presumes a great deal about prehistoric mating practices based on the historical record and/or shoddy reasoning from minimal evidence.

Genetic evidence offers a potential check on Frost's guesses. Circularly ignoring (or trying to rationalize away) evidence because it doesn't support you while heralding evidence when you believe it does is not science.

Tod said...

"Peter Frost presumes a great deal
about prehistoric mating practices based on the historical record,... reasoning from minimal evidence."

In relation to his theory about north and East European marriage practices in the 5000 years after the last glacial maximum. Yes, I can't disagree that the theory is a very bold one considering how little is known.

But in relation to the origin of black Africans (although it's another bold theory) he could cite any amount of studies. Compared to the rest of the world polygyny is very common in Africa; in West Africa it is most common of all. And that's is the way it was as far back as you can go in the record. If you stack that against the 2 studies' contradictory claims which found that polygyny was not common in W. Africa it casts doubt on their methods.

n/a said...

Frost can cite studies about marriage. He can say comparatively little about breeding.

Anonymous said...

"Tod" and "ben10", those peter frost worshippers, are some real creepy ass nerds.

n/a said...

"Tod" is a strange one, I agree. I don't have a problem with Ben10.

Gordon said...

What namely you're saying is a terrible blunder.
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