Saturday, June 1, 2013

Just for show?


Of all humans, male and female, European women have the whitest skin and the most diverse range of hair and eye colors. Are European physical characteristics really female characteristics? (source)


People of European origin have an unusually diverse palette of hair and eye colors. This diversity is commonly ascribed to their unusually white skin. Ancestral Europeans became lighter-skinned, and this genetic change therefore caused other changes to hair and eye pigmentation.

Actually, the genetic changes are different in each case. European skin turned white through a replacement of alleles, primarily at TYRP1, SLC24A5, and SLC45A2. European hair and eyes diversified in color through a proliferation of new alleles, primarily at MC1R for hair color and in the HERC2-OCA2 region for eye color.

It now appears that this diversification has occurred at other gene loci as well. Zhang et al. (2013) report that a region downstream from EDNRB is associated with differences in hair color and that two other loci, VASH2 and POLS, are associated with differences in eye color. Sulem et al. (2008) report that TPCN2 is associated with differences in hair color and that ASIP is associated with red hair.

A common selection pressure, not a common gene

This is further proof that a selection pressure created the visual effect of color diversity by acting on whatever genes it could. In short, this diverse palette of hues seems to exist “just for show.”

The evolutionary problem is spelled out by Walsh et al. (2012):

People of European descent display the widest variation in pigmentation traits, such as iris (eye) and hair colouration, in the world. In particular, eye colour variation is nearly restricted to people of (at least partial) European descent. Eye colour categories here often concern blue, brown and intermediate (green, etc.). In the rest of the world, people tend to have brown eye colour, which is considered to be the ancestral human trait in agreement with the Out-of-Africa hypothesis of modern humans. The current variation in eye colour is thought to have originated via a genetic founder event involving non-brown irises in early European history. It is furthermore assumed that eye colour variation in Europe has been shaped by positive selection via sexual selection i.e., mate choice preference. Alternatively it has been proposed that eye colour variation evolved via a correlation with skin colour and its environmental adaptation e.g. maximizing vitamin D conversion in low levels of UV radiation, or as a combination of both. One suggested geographic region for the origin of blue eye colour in Europe is the southern Baltic, as indicated by concentric rings of decreasing frequency of the blue eye colour trait spreading from the southern Baltic region, resulting in a strong north–south gradient in blue eye colour frequency across Europe.

It is doubtful whether a lack of vitamin D at northern latitudes played a role in the whitening of European skin, let alone in the diversifying of European hair and eye color. As Elias and Williams (2012) note, certain northern populations whitened much more than others:

An obvious feature of the northward dispersal of humans is a quasi-geographic reduction in pigmentation (Murray, 1934; Loomis, 1967; Chaplin and Jablonski, 2009). Coloration varies greatly among northerners. Native Inuit display medium-to-dark (type III/IV), rather than light pigmentation, and both northern and central-dwelling Asians display medium (type III) pigmentation. Recent population genetic data show that the reduction in skin pigmentation occurred sporadically and incompletely in northern and Asian populations (Sturm, 2009). Moreover, while modern humans reached Central Europe ≈40 ka (thousands of years ago), they reached northern Europe only after the last ice sheets receded less than 11 ka. It is only these humans that display light pigmentation, and recent molecular genetic studies suggest that the very light pigmentation of northern Europeans did not develop until 5-6 ka (Norton et al., 2007; Norton and Hammer, 2008).


Heather Norton’s estimate for European skin whitening (which she set within a broader range of 3,000 to 12,000 years ago) has been revised upward by Sandra Beleza to a range of 11,000 to 19,000 years ago, the second estimate being now accepted as the better one by Norton (Beleza et al., 2013; Norton and Hammer, 2007; Norton, 2012). This time period still began long after the entry of modern humans into Europe, the implication being that ancestral Europeans were brown-skinned for tens of thousands of years.

Elias and Williams (2012) also note that the vitamin-D hypothesis cannot explain the changes to European hair color, since hair is not involved in vitamin-D synthesis. Their alternate hypothesis is that European skin became white as a way to cut back on unnecessary energy expenditure:

[…] a declining need to heavily pigment the epidermis favored the retention of mutations in genes that reduced pigment synthesis, thereby diverting energy toward the production of more urgently-needed proteins.

But why, then, did ancestral Europeans wait over twenty thousand years before cutting back on this unnecessary expenditure? And why would this expenditure be less unnecessary at northern latitudes in Asia and North America? Moreover, in the case of hair color, what has happened is not a loss of pigment but rather a shift from production of one kind of pigment, i.e., eumelanin (black-brown hues), to production of another, i.e., pheomelanin (yellow-red hues).

Sexual selection?

Color polymorphisms are not limited to humans. They occur in many other species for reasons that Hofreiter and Schöneberg (2010) discuss in a recent review article. One reason is crypsis—the need to blend into a background that may vary from one place to another. Deer mice, for instance, have light fur where the ground is likewise light in color and dark fur where it is dark in color. Another reason is aposematism—individuals with a rare coloration have better chances of survival, since they are a poorer match for a predator’s search image.

Such a frequency dependent effect, favouring the rarer colour morphs, is also known from sexual selection, when females preferentially mate with rare colour morph males, a phenomenon also known from guppies. (Hofreiter and Schöneberg, 2010)

This kind of color polymorphism typically involves bright colors, since sexual selection is influenced by sensory biases that favor not only novel colors but also bright ones as well. In fish species, for instance, color morphs are often red because a sensory bias for this color has developed irrespective of mating contexts.

If we look at the polymorphisms for human hair and eye color, the recently evolved “European” hues tend to be brighter than the species norm of black hair and brown eyes. Eyes may be light blue, but not navy blue. Hair may be carrot red, but not beetroot red. Sexual selection is also indicated by a greater variability of hair color in women, with red hair being especially more frequent (Shekar et al., 2008).

But why?

Why would sexual selection have been more intense among ancestral Europeans? Such selection happens when too many of one sex are competing to mate with too few of the other. In most mammals, the males do the competing—because polygyny dries up the pool of available females. So the males are brilliantly colored, and the females duller in appearance.

But here we have the reverse. Hair color is brighter and more diverse in European women than in European men. We see a similar pattern with skin color. “European” physical traits seem to be female traits. It looks as though sexual selection primarily targeted women and then secondarily spilled over on to men.

This unusual color scheme seems to result from the unusual steppe-tundra that covered the plains of northern and eastern Europe during the last ice age 25,000 to 10,000 years ago. This environment offered ancestral Europeans a huge amount of edible biomass, but nearly all of it was locked up as meat in wandering herds of reindeer and other herbivores. Since male hunters provided almost all of the food for their wives and offspring, the cost of supporting a second wife and her children was prohibitive for them, being feasible for only the ablest hunters. At the same time, pursuit of migratory game greatly lengthened the mean hunting distance and boosted male death rates accordingly.

Thus, limited polygyny, combined with higher hunting-related mortality, skewed the mate market towards a shortage of available men. Women had to compete for men, unlike the situation among tropical humans and most other mammalian species. This intense mate competition in turn drove sexual selection for colorful features that could, by their brightness or their novelty, catch the attention of a prospective mate (Frost, 2006; Frost, 2008).

References

Beleza, S., A. Murias dos Santos, B. McEvoy, I. Alves, C. Martinho, E. Cameron, M.D. Shriver, E.J. Parra, and J. Rocha. (2013). The timing of pigmentation lightening in Europeans, Molecular Biology and Evolution, 30, 24-35.

Frost, P. (2006). European hair and eye color - A case of frequency-dependent sexual selection? Evolution and Human Behavior, 27, 85-103.

Frost, P. (2008). Sexual selection and human geographic variation, Journal of Social, Evolutionary,and Cultural Psychology, 2(4), 169-191. http://137.140.1.71/jsec/articles/volume2/issue4/NEEPSfrost.pdf

Hofreiter, M., and T. Schöneberg. (2010). The genetic and evolutionary basis of colour variation in vertebrates, Cellular and Molecular Life Sciences, 67, 2591–2603.

Norton, H.L., and M.F. Hammer. (2007). Sequence variation in the pigmentation candidate gene SLC24A5 and evidence for independent evolution of light skin in European and East Asian populations. Program of the 77th Annual Meeting of the American Association of Physical Anthropologists, p. 179

Norton, H.L. (2012). Personal communication

Shekar, S.N., D.L. Duffy, T. Frudakis, G.W. Montgomery, M.R. James, R.A. Sturm, and N.G. Martin. (2008). Spectrophotometric methods for quantifying pigmentation in human hair—Influence of MC1R genotype and environment, Photochemistry and Photobiology, 84, 719–726.

Sulem, P., D.F Gudbjartsson, S.N. Stacey, A. Helgason, T. Rafnar, M. Jakobsdottir, S. Steinberg, S.A. Gudjonsson, A. Palsson, G. Thorleifsson, S. Palsson, B. Sigurgeirsson, K. Thorisdottir, R. Ragnarsson, K.R. Benediktsdottir, K.K. Aben, S.H. Vermeulen, A.M. Goldstein, M.A. Tucker, L.A. Kiemeney, J.H. Olafsson, J. Gulcher, A. Kong, U. Thorsteinsdottir, and K. Stefansson. (2008). Two newly identified genetic determinants of pigmentation in Europeans, Nature Genetics, 40, 835-837.

Walsh, S., A. Wollstein, F. Liu, U. Chakravarthy, M. Rahu, J.H. Seland, G. Soubrane, L. Tomazzoli, F. Topouzis, J.R. Vingerling, J. Vioque, A.E. Fletcher, K.N. Ballantyne, and M. Kayser. (2012). DNA-based eye colour prediction across Europe with the IrisPlex system, Forensic Science International: Genetics, 6, 330–340.


Zhang, M., F. Song, L. Liang, H. Nan, J. Zhang, H. Liu, L.-E. Wang, Q. Wei, J.E. Lee, C.I. Amos, P. Kraft, A.A. Qureshi, and J. Han. (2013). Genome-wide association studies identify several new loci associated with pigmentation traits and skin cancer risk in European Americans, Human Molecular Genetics, advance access 1–12 

53 comments:

Richard Sharpe said...

This is a continuation of your earlier themes, and I admit that it is an attractive explanation.

However, what concerns me is that if we accept the notion of greater male mortality in that environment such that females were selected for visual appearance to improve their mating chances, there must also have been selection on females for more male offspring.

In an environment where males of mating age are scarce those women who produce more male offspring who reach mating age and do successfully reproduce have a reproductive advantage. Surely.

And yet we see Caucasian live birth ratios at around 105 live males per 100 live females, which achieves parity in modern environments at around age 26 or so, but in those more strenuous times would surely have kept the supply of males at mating age much less than 1:1.

Anonymous I said...

"In an environment where males of mating age are scarce those women who produce more male offspring who reach mating age and do successfully reproduce have a reproductive advantage. Surely."

Mmm... yes, but your conclusion does not follow. In an environment where males have high death rates, investing in a male is still risky. Males are winnowed out on the hunt, and females by the campfire, but this means they're really both culled, unattractive women and poor male hunters together.

Ultimately, Peter's model doesn't even require male death at all. It could have happened that way, but it could just as easily have been that the unattractive women couldn't be provisioned by good hunters, who then stuck with only one wife. These unattractive women were then left to be provisioned by poor hunters - but they had lower reproductive output and higher offspring mortality because they weren't provisioned as well.

But one curious corollary of Peter's model, which he hasn't discussed, is how this would affect female psychological characteristics. Wouldn't European women be expected to be more psychologically attractive to males as well? Unless men chose mates without any regard for their behavior or interests (which is extremely doubtful) this would suggest that the women who were more interested in talking about his spear collection and hunting tactics, as well as women with greater overall interest in sex, would also have a reproductive advantage in prehistoric Europe.

In other words, I think the Frost model makes a prediction: European women will not only be more colorful, but they will be more masculine in their interests than women of other ethnic origins. We might further expect that the women would then pass such traits onto their sons, resulting in more masculine men, as well. This is a question worth asking - do Europeans, and particularly European women, have more male stereotypical interests and behaviors than other populations?

(Everything that I've read suggests they do not.)

Pamela said...

Hi Peter,

First, I want to thank you again for being a breath of fresh air in having a focus on the female role in evolution. Many of the HBD crowd act as if all changes occur as a function of male activity and women just happen to be along for the ride.

Second, I find it interesting and significant that you describe European physical traits as "female" in nature. This appears correct to the naked eye (as well as empirically) and makes a strong case for your argument of sexual selection.

Third, I'd like to offer this off-the-top thought: might there not also have been a level of selection among European women for those men who were less likely to be disposed towards polygamy and more likely to be disposed towards paternal investment? It's clear that polygyny and harem environments was not present in European culture long after the constraints of weather and hunting disappeared. Perhaps women chose mates whose genetic predisposition led to greater paternal investment.

Finally, in response to "Anonymous":

"In other words, I think the Frost model makes a prediction: European women will not only be more colorful, but they will be more masculine in their interests than women of other ethnic origins. We might further expect that the women would then pass such traits onto their sons, resulting in more masculine men, as well. This is a question worth asking - do Europeans, and particularly European women, have more male stereotypical interests and behaviors than other populations?"

Your statement is somewhat incorrect. Women of Caucasian/European origin show much greater tendency towards what are considered "masculine" action traits than women of other backgrounds. (That is to distinguish between European female traits which are more feminine in physical appearance.) Ancient sources universally describe the women of European tribes as being very engaged in warfare and battle (see Strabo, Ammianus Marcellinus, Tacitus, Polybius, Diodurus Siclus, et al.) Also there is recent scientific research which shows that European women have higher cardiovascular fitness, pain tolerance and muscular strength which would lead one to believe that their female ancestors may have been under a physical fitness selection pressure:

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3111145/

http://rodrigoborges.hospedagemdesites.ws/principal/pdf/obesidade_11.pdf

These facts could indicate that ancient European women were interested in the hunting/fighting tactics that you mention.

Richard Sharpe said...

Mmm... yes, but your conclusion does not follow. In an environment where males have high death rates, investing in a male is still risky. Males are winnowed out on the hunt, and females by the campfire, but this means they're really both culled, unattractive women and poor male hunters together.

Recently, where I work, the ducks laid eggs. Three duck had some ten eggs each hatch into ducklings. Some six weeks later, they are down to zero, three and four ducklings. With such risks, why bother laying eggs?

Sure, having a male is risky, but by producing more male offspring, you can potentially bring more to reproductive age, and that investment will pay off. However, by having female offspring then you have to endow them with something extra to make then stand out.

Clearly, women who have the standout characteristics, at least when they are a relatively low proportion of the population, do not need to increase the number of their male offspring. Perhaps it is the non-standout women who have gone that route.

Anonymous said...

Pamela opined:

First, I want to thank you again for being a breath of fresh air in having a focus on the female role in evolution. Many of the HBD crowd act as if all changes occur as a function of male activity and women just happen to be along for the ride.

Yes, those strong and empowered women have been directing evolution all along.

The reality is that we are all along for the ride because the environment is selecting those of us who have the right combination of genes and none of us get to choose our genes. The choosing was done by our parents.

Anonymous I said...

Hi Pamela.

The sources you cited indicated that European women were stronger than African American women, not that they were psychologically masculine. It is widely known that measures of strength and health correlate with diet and socioeconomic status.

As for the historical sources, they are suggestive, but not entirely convincing. The historical record isn't a complete anthropological survey, and even if it were, it also tells about pugnacious non-European women - there's an interesting list in Wikipedia that's worth a look:

http://en.wikipedia.org/wiki/List_of_women_warriors_in_folklore

Ultimately, the best quality data that we have comes from the soft sciences, where traits like masculinity-femininity have been measured for decades. The foremost authority on Masculinity-Femininity is probably Richard Lippa, whose conception of M/F, as measured specifically by personal and career interests, is probably the closest test of this model that I can think of. What the Frost model seems to imply isn't necessarily that European women are fighters, but rather that they are the sorts of people whom men would like to hang out with because of their interests.

Looking at his 2008 paper, "Sex Differences in Personality Traits and Gender-Related Occupational Preferences across 53 Nations: Testing Evolutionary and Social-Environmental Theories," there isn't a clear difference between the European and non-European nations in the masculine interests of women. In fact, women have the most masculine interests in - drumroll - Israel. After that, Finland, then a toss up between New Zealand and Thailand. On the feminine side, we have Venezuela, Pakistan, and then Singapore, which would be consistent with the model, but then the Czech Republic and Poland. So the most straightforward prediction that European hunter-gatherer men would select for women they could talk to about their interests fails.

But I also mentioned sex drive as a characteristic men might select for in women - men have higher sex drives, and generally prefer wives with sex drives closer to their own rather than wives with perpetual headaches. I'll note here that the prediction is not necessarily that clear - men sometimes prefer sexually inexperienced and faithful women, and we might expect European men to have demanded a woman remain patient on long hunting trips. But browsing around, I notice that the data is available in another of Richard Lippa's studies.

Checking out his 2009 "Sex Differences in Sex Drive, Sociosexuality, and Height across 53 Nations: Testing Evolutionary and Social Structural Theories," I note, surprisingly, that there is a clear trend for European women to show sex drives closer to their males than elsewhere - the three nations with the smallest sex differences in sex drive were all European (Russia, Czech Republic, Estonia) while the seven nations with the largest sex drive differences between sexes were non-European (Venezuela again, then Cyprus, India, Malta, Saudi Arabia, Trinidad, and Pakistan).

Of course, there may be some other explanation, such as a longer recent history for strong gender inequality which would probably select against women with much sexual interest. But the smaller differences between male and female sex drives in European nations compared to elsewhere could be taken as support of Peter's model.

Anonymous said...

But, for example, darker Southern European women don't actually get judged as "less feminine" in appearance than Northern European men. Lighter Baltic people aren't actually judged more feminine than darker people from Northern France, in any context I've seen.

It seems more compelling to me that color selection in Northern European people may have been a different path - some populations select for some feminine traits and some for different feminine traits (etc for masculine traits).

Also, as you've said before "Women have a higher luminous contrast between their facial skin and their lips and eyes" and I think this is also true for hair (at least in Mediterranean populations), so it is hard to see blonde hair and blue eyes emerging deterministically from this paradigm (as they would reduce brightness contrast between eyes and skin and thus "femininity").

Even if they make women more striking, they make them less "feminine". This may help to explain differential evolution in the Mongoloid populations from the European - the ancestral Europeans sought the more "striking" women, while the ancestral Mongoloids sought the most female typical (with very high hair and skin contrast). Both would seek to select for more attractive females, but along different vectors.

Sean said...

This new time frame for the origin of skin lightening mutations in Europe also impacts on the agriculture hypothesis; it falls if Europeans turned white 11,000 to 19,000 years ago, instead of in the Neolithic.

If white skin was required for sufficient vitamin D photoproduction, black Africans growing up in in northern Europe (wearing clothes) would surely be sickly, but they're not--far from it! Moreover this argument applies to Elias and Williams (2012) alternate hypothesis:[…] "a declining need to heavily pigment the epidermis favored the retention of mutations in genes that reduced pigment synthesis, thereby diverting energy toward the production of more urgently-needed proteins". The hypothesis of Elias and Williams can't explain why Black Africans, with their pigment synthesis burden, are not at any disadvantage in Europe and actually dominate many popular European sports.

In 2007 everything was against Peter's hypothesis. Now it is the only one left standing.

Anonymous said...

If white skin was required for sufficient vitamin D photoproduction, black Africans growing up in in northern Europe (wearing clothes) would surely be sickly, but they're not--far from it!

Aren't modern industrial food products fortified with Vitamin D? Even things like orange juice have Vitamin D added.

John Adams said...

Cochran and Harpeding wrote about a possible reason for this in The 10K Explosion.

http://en.wikipedia.org/wiki/The_10,000_Year_Explosion#Agriculture

"Farming, rather than just reduced sunlight, may have helped trigger pale skin in Europeans.

Several decades ago, Stanford's Cavalli-Sforza had argued that European hunter-gatherers, herders and fishers could have survived from the vitamin D content of their diet, alone. Only when farming took hold did Europeans - replacing meat and fish with grain - need to absorb more sunlight to produce the vitamin in their skin.[8]"

The reason this would have effected East Asians less is because rice, particularly White rice seems to be less harmful. White rice lacks any significant amount of phytic acid, which binds to minerals and makes them unavailable: http://www.westonaprice.org/food-features/living-with-phytic-acid

The idea of sexual selection reminds me of an article I read about why blondes may be found more attractive. It seemed to partially be due to rarity. They cited a study done that showed men ten pictures of women, and when only one of them was brunette they tended to be found the most attractive. It sets them apart from the crowd, makes them stand out.

I also recall reading that blond hair acts similar to a fiber optic and transmits sunlight to the scalp, which is in line with the Vitamin D/agriculture hypothesis.

Another aspect of the sexual selection hypothesis is the difference in individuality vs collectivism between Europeans and East Asians. More individualistic personalities will be complemented by greater physical differentiation. Reminds me of this paper by Gregory Clark on the genes for capitalism: http://www.econ.ucdavis.edu/faculty/gclark/papers/Capitalism%20Genes.pdf
And of course there are significant average differences for serotonin transporter lengths and platelet serotonin between populations: http://neuropolitics.org/defaultjun09.asp
http://www.economist.com/node/21532247

Anonymous said...

"However, what concerns me is that if we accept the notion of greater male mortality in that environment"

I'm not sure this is needed as if there was a higher mortality it would on average effect the less good hunters anyway.

I think simply being able to provide more calories consistently and yet not enough to feed multiple families would create the reproductive advantage necessary on its own.

The better hunters got the pick of the girls and so the pick of the girls had more surviving daughters.

As to other traits that may have co-evolved under the same pressure i'd have thought monogamous ones would be likely candidates.

The only thing i have a problem with is why other very hunting dependent populations like Eskimos didn't have the same pressures?

Also, sexual selection requires sexual selection i.e. not parentally chosen spouses - the individuals concerned have to be free to choose for themselves. Although W.E.I.R.D populations take that idea for granted but it seems to be quite rare historically.

Is it common or unusual for hunter-gatherers to choose their own spouse or is it arranged by the parents?

(If Eskimo had arranged marriages that would answer the first question.)

Pamela said...

Anonymous said:

"Yes, those strong and empowered women have been directing evolution all along."

I'm not quite sure how you derived that notion from my statement, so your response is rather odd. The point was that the role of women is often overlooked by the more phallocentric in the evo community, not that women were the only drivers of evolution. When one sees a call for supremacy in a simple call for equality it typically represents a level of discomfort or insecurity about those one seeks to exclude.

Anonymous said:
"The reality is that we are all along for the ride"

My point exactly. Kudos to you for agreeing! :-)

Pamela said...

Anonymous said:

"The sources you cited indicated that European women were stronger than African American women, not that they were psychologically masculine. It is widely known that measures of strength and health correlate with diet and socioeconomic status."

Once again, you're taking the discussion in a direction that has nothing to do with the response. The point of Peter's post was about the nature of sexual selection. It was you who made the point of lack of so-called "masculine" traits among European women. (Your term, not mine-- I'd simply term them as traits of physical aggressiveness or fitness.)

Moreover, if you read the citations more clearly, you will see that socioceconomic and dietary factors were controlled for such that they were not considered statistically significant in the analysis.

My point was not to argue some physical supremacy of European women, but rather to counter your statement that such physical strength and aggressiveness is not present in women of European origin. Frankly, it's a noxious stereotype whose day has run it's course.

Anonymous said:

"As for the historical sources, they are suggestive, but not entirely convincing. The historical record isn't a complete anthropological survey, and even if it were, it also tells about pugnacious non-European women - there's an interesting list in Wikipedia that's worth a look:

http://en.wikipedia.org/wiki/List_of_women_warriors_in_folklore"

I've read the wikipedia citation before, and while I prefer not to use Wikipedia as a basis for my analysis (I prefer more primary sources), I would invite you to consider the following: while the Wikipedia article that you cited very clearly shows that there have been individual warrior women in various cultures, more significant is the fact that European history is rife with multiple tribes of women who were engaged in the more "masculine" activities that you mentioned. I have been unable to find any other areas of the world where such activities were a widespread cultural attribute expected of women in those cultures. In other words, in ancient European tribes it was more the norm rather than the exception to see women display these so-called masculine attributes. Please feel free to look up (on Wikipedia or elsewhere) further information about the Iceni, the Bracari, the Gauls, the Cimbri, the Sitones, the Suiones, just to name a few.

Anonymous said:

"Looking at his 2008 paper, "Sex Differences in Personality Traits and Gender-Related Occupational Preferences across 53 Nations: Testing Evolutionary and Social-Environmental Theories," there isn't a clear difference between the European and non-European nations in the masculine interests of women."

That is quite interesting, and I'll look into the paper further. However, it doesn't really directly speak to genetic factors as such. When talking about evolutionary selection, behavioral and physical characteristics are much more convincing than occupational choices which can more easily be influenced by such things as economic necessity.

Anonymous said:

"Checking out his 2009 "Sex Differences in Sex Drive, Sociosexuality, and Height across 53 Nations: Testing Evolutionary and Social Structural Theories," I note, surprisingly, that there is a clear trend for European women to show sex drives closer to their males than elsewhere."

I'm not surprised. This definitely seems in line with the historical evidence. Again, as you research the tribes mentioned above, please note what is mentioned about their sexual behavior. While you say that the ancient sources are "suggestive," they still represent our best firsthand accounts of the behavior of ancient European women.

Anonymous said...

Cochran appears to take a swipe here:

http://westhunt.wordpress.com/2013/06/03/diss-ability/

"This could also explain selective sweeps of gene variants causing striking eye colors in Europeans – an increase in reproductive fitness flowing from a ability to curse others makes sense. More than sexual selection, anyhow."

Paragon said...

In hunter-gatherer populations, a woman is pregnant a large part of the time. Her calcium requirement increases because of the developing fetus. Intestinal calcium absorption is enhanced by vitamin D. The synthesis of vitamin D depends on capacity of the skin to allow the UV component of sunlight to penetrate. UV penetration is more efficient when the skin is light in color. This would explain why natural selection favored lighter skin in women more so than in men.

On the other hand, UV light is harmful (it destroys folic acid). Adults are exposed to more UV light than children are. Therefore, skin color is darker in adults. Because the biologically optimal skin color is lighter in women than men, the preference for light skin color should be stronger in men than women.

Master Dogen said...

Can you help me understand why novel pigmentation would be sexually selected for? I certainly dig redheads and blondes, but is it just because they are more noticeable? Is the mechanism at work purely the catching of the eye?

Wouldn't any "peacocking" on the part of females require extreme, extreme superabundance of males? I never turn down a sexy brunette just because there's a blonde in the room. If the would-be blonde in the ancestral environment was young and pretty, presumably she could just wait thirty minutes to get impregnated while the male was busy with her sister.

I beg ignorance on the math at play, so please be gentle. It just seems to me that the selection pressure for female pigmentation must be awfully weak, though I do see how it could function given extreme circumstances and a lot of time. It just seems like something is still missing here.

I suppose I was expecting to find that the reason blondes are more attractive is because blondness is a proxy for some other adaptive quality. Forgive my ignorance and I welcome any enlightenment.

Master Dogen said...

Whoops. I meant extreme, extreme superabundance of females, of course.

tyrionlannister69 said...



Dr. Frost proposes a sensory bias model (nonadaptive sexual selection) of mate preferences that is structured several ideas:

1) Light skin became a trait associated with childishness (neoteny) and femininity and men prefer women with feminine and childish traits. This gave rise to the preference for markedly lighter skin and hair color.


PROS:
1.a) Neoteny in female faces was a sensory bias that selected for age-related fecundity. It is a supernormal cue of youth, not a cue of actual phenotypic and genetic quality. This almost automatic reaction has led to the assumption that babyness could also be involved in adult attractiveness perception, because it could signal neoteny or youth.

CONTRA:

2.a) Even a sensory bias model should expect that, as a trait is driven to be more extreme, some individuals should be better able to display it and, hence, it should become correlated with quality (Kokko et al. 2003).

2.b) The presence of babyness features in a female face leads to a transfer of personality traits. Personality traits coupled to babyness are positive and negative: babyness can signal ‘submission’ and ‘eliciting parental care’ but it also signals ‘incompetence’, which would be the last trait in a partner one would look for. Raising offspring requires competence.
2.c) “caring and sharing” looks in women or something along the lines of infantile looks (e.g., lighter skin, lighter hair) that supposedly bring out the nurturing element in men and facilitate their acting as better providers to their wife. In many species, the males often kill babies of other males. Human males are hardwired for nulliparous women, so ancestrales males generally would´nt give a damn about babies not fathered by them. Human males are typically sexually interested in women who are not fathered by them or their close relatives. So why should one expect more infantile features in distantly-related women to win over men and bring out the nurturing element in them? In other words, selection for blonder hair or lighter skin doesn’t have to be because these are more infantile.

2) Estrogen lightens the skin whereas progesterone darkens it. Therefore, skin color in women is darker during pregnancy and lighter around the time of ovulation. This is more cogently explained by sexual selection rather than natural selection because natural selection would dictate that skin color in females is lighter during pregnancy when the calcium requirement is particularly high.

3) The parallel evolutionary changes in skin color and preferences for skin color in women and men can be explained in terms of the common genetic determination of skin color in both sexes. In turn, the parallel evolutionary changes in skin and hair color and the preferences for them can be explained in terms of the common genetic determination of skin and hair color. Because skin color is lighter in women than men, the contrast between skin color and eye and lip color is greater in women than men.

PRO:

a) RUSSELL (2003) showed that digitally increasing the contrast by darkening the eyes and lips increases FacA in female faces but decreases FacA in male faces.

b) The preference for light skin is present in most human populations [VAN DEN BERGHE and FROST [1986]. However, the preference within a population is for skin tones that are lighter for that population and not the lightest possible skin tones. In most cultures, the preference for light skin in women is stronger than the preference for light skin in men [VAN DEN BERGHE and FROST 1986]. There is also a general preference for light hair in women and for dark hair in men [FEINMAN and GILL 1978, JONES 1996b].

tyrionlannister69 said...

3) Etcoff (1999) hypothetize that light skin is also a better clue to health than dark skin. Many disorders, including anemia, cyanosis, jaundice and infection, are easier to detect in an individual with lighter skin. Therefore, it makes sense not to choose a partner with dark skin, because they may be concealing cues to poor biological quality.

Regarding eyes and hair colour, Frost proposes that are determined by frequency-dependent selection. This means that rare, exceptional colors are preferred.

Pro: Thelen (1983) showed that preference for hair colour depends on the distribution of hair colour in a population. Males prefer the ‘rare’ colour.

Contra:

a) LITTLE et al. [2003] found that both men and women preferred the same eye color and hair color that their opposite- sex parent possessed.
b) LAENG et al. [2007] found a particularly strong preference of men for own-eyed colour women, which is probably an adaptation for detection of non-paternity.

My thoughts:

It would expect selection to have favored males in human evolutionary history who perceived indicators of true female mate value, not supernormal stimuli without mate value, as hair or eye colour. The Dr. Frost´s model would be a sensory bias model or fisherian sexual selection mechanism because sexual selection favors features that do not correlate with fitness except in terms of attractiveness to the opposite sex.

The question that arises is whether people with light skin and wide range of bright hair and eye colors are really distinguished by a high biological quality and a high mate value to an observer. It should be emphasized that a possible lack of association between hair colour and biological quality does mean nonadaptiveness of facial preferences, because they don´t provide information about female phenotypic and genetic quality.

It seems that Frost´s theory posits that north European male´s mating preferences were by-products of natural selection on sensory systems. It should be explain the unique features of sensory bias relative to the alternative models by considering each in the same quantitative genetic framework. The sensory bias hypothesis as an explanation for the evolution of female preferences remains to be determined.

I wonder whether indirect selection, arising through genetic associations (linkage disequilibrium) during the sexual selection that sensory bias imposes, can itself influence the evolution of preference strength. I think that only in a model where there is restricted migration between different patches that favor different female phenotypes, where that preference strength could evolve. The role of indirect selection in the evolution of sensory bias is of particular interest because of ongoing speculation regarding the role of sensory bias in the evolution of reproductive isolation.

Anonymous said...

Paragon
"In hunter-gatherer populations, a woman is pregnant a large part of the time."

My understanding is that hunter-gatherers use late weaning to spread out pregnancies.

.
Master Dogen
"If the would-be blonde in the ancestral environment was young and pretty, presumably she could just wait thirty minutes to get impregnated while the male was busy with her sister."

Sexual selection isn't about the sex it's about the children i.e. do the people who choose option a) have more surviving children on average then the people who choose option b).

In an environment where the female can't gather enough food for her children then having sex with lots of women is pointless as you can't keep the resulting children alive.

In a hunting-centric environment what keeps one set of children alive is being a good hunter and being focused on that one set of children (or at least serial monogamy once the first set are grown).

So in that kind of environment it's easy to see that a woman attracted to monogamous good hunters would have more surviving kids.

However i'm not sure men being attracted solely on hair and/or eye colour makes *enough* sense on its own.

Although it does make sense in terms of simple attraction as if the best hunters did select purely on that basis then *their* good hunting traits would lead to more surviving children from the couple but in a harsh environment i'd expect the female traits being selected on to somehow have some direct signalling effect i.e. they were better able to signal health and fertility somehow.

Anonymous said...

"n other words, I think the Frost model makes a prediction: European women will not only be more colorful, but they will be more masculine in their interests than women of other ethnic origins."

Only if "masculine interests" aren't correlated with masculine physical traits, which they appear to be.

I'm also dubious that there is a long-lasting non-culture specific for 'women who share my interests.'

Osvaldo M.

Peter Fros_ said...

Richard,

Among humans, the highest sex ratios occur within a region stretching from Eastern Europe to East Asia. The lowest occur in sub-Saharan Africa. I suspect this reflects an adaptation to the operational sex ratio, as you suggest.

In modern societies, the sex ratio no longer balances out in the mid twenties. It now remains male-biased until the later forties or early fifties.

Anon,

The increase in the male death rate is also relevant. If we look at Arctic hunter-gatherers in general, the operational sex ratio is most lopsided where the men have to pursue game animals on foot over long distances. That kind of environment (steppe-tundra) has been limited in extent during postglacial times. During the last ice age, there was steppe-tundra in northern Asia, but it was not coninuously inhabited by humans (because it was farther north and more arid than the European steppe-tundra).

Pamela,

The problem is that psychological traits are a product of both genes and upbringing. I suspect that sexual selection has favored certain psychological traits, particularly sexual response and the strength of pair bonds, but this would be hard to prove one way or the other.

Anon,

Yes, there is a strong trend for hair color to be darker than skin color (the reverse is very rare in humans). I suspect that dark head hair enhances the relative lightness of facial skin.

Then how did light hair evolve? Again, there are several factors at work here, one of them being the "novelty effect." There seems to be sexual selection for female hair color on the basis of novelty, i.e., the rarer the hair color, the more it appeals to men. A strong novelty effect would overwhelm other factors until the rare hair color ceases to be rare.

Sean,

In 2007, Greg Cochran was against my hypothesis, and his opinion counts for a lot (especially in HBD circles). I don't mind him having an alternate hypothesis. That's normal. What's abnormal is the nature of his "criticisms" -- which are high on ridicule and low on substance. It's almost as if I had said his wife wears army boots.

John Adams,

European skin became white between 11,000 and 19,000 years ago. That's long before the advent of farming in Europe (which began about 10,000 years ago in the extreme southeast and reached northern Europe much later).

In any case, the depigmentation of European skin doesn't explain the changes to European hair and eye color, which are qualitatively different. The latter changes involve different genes and a proliferation of new alleles (as opposed to a replacement of one allele by another).

Anon,

The Eskimos are a good example of why a low polygyny rate is not enough to create a sufficiently strong pressure of sexual selection. We do in fact see non-black hair and non-brown eyes among the Eskimos of the northwestern Canadian Arctic. This doesn't seem to be due to European admixture and may be an early stage of the same evolutionary trajectory that early Europeans went through.

http://en.wikipedia.org/wiki/Blond_Eskimos

Master Dogen, Tyrion,

When hair or eye color are subjected to intense sexual selection, there seem to be two main determinants of male preference: color brightness and color novelty. These two factors become important when men are presented with an abundance of female candidates who are otherwise equal in quality.

Tyrion,

This is the debate between "adaptationists" and "non-adaptationists" over the determinants of sexual selection. In my opinion, eye-catching qualities are adaptive. When people buy a flashy-looking product (e.g., a car, a motorcycle, or a magazine), is this flashiness somehow an indicator of the product's quality? Isn't it just a way to exploit a sensory bias that exists for a totally different reason?

Sean said...

Modern life may cause sun exposure, skin pigmentation mismatch.

It is not true that whites' reproduction at the equator encounters any problem with photo-destruction of folic acid. Nor is it true that black Africans, clothed (and with an agricultural diet) while reproducing in north Europe have weak bones; they actually have far more robust bones than whites.

An Institute of Medicine report determined that the ideal vitamin D level for modern clothed inhabitants of north America (black or white) is the one virtually everyone already has: 20ng/ml, and there no evidence for beneficial effects on non-bone health. See here. Levels 2 or 3 times higher than the IoM recommend, as latitude hypothesis proponents support, are absurd. A few minutes in the sun gives you more vitamin D than a liter of D-fortified milk. Subsequently, studies have found increases in inflammation and higher mortality at levels over 20ng/ml) See here and here. Moreover, A common variant in the CYP2R1 gene that predisposes people to high vitamin D levels, is less common in long lived people. See here

Sean said...

Gigerenzer says "There is nevertheless a risk that a demonstration of ecological rationality of a given heuristic in a given environment will mislead someone who uses this evidence alone to infer adaptation. [...]
... pink flamingos camouflaged against pink sunsets. Sexual selection is the real explanation for most bright plumage"


Gigerenzer "Paradoxically, in these situations a more noncompensatory environment may lead to examining cues in increasing order of validity (the reverse of take-the-best), at least in cases where the quantitative nature of cues means that cue values are unlikely to tie. As the chooser gets progressively closer or more willing to take risks, more cues become available; it should be adapted to read those new cues whose validity outweighs earlier cues, but less valid new cues are unlikely to provide useful additional information and so might be ignored. With sexual selection, it could often be that particular traits evolve as signals because of the stage of the assessment process in which they can be examined, rather than that the cue informativeness of preexisting signals has favored an order of inspection"

Anonymous said...

Peter Frost
"The Eskimos are a good example of why a low polygyny rate is not enough to create a sufficiently strong pressure of sexual selection."

Yes it seems like there ought to be other candidate populations if it was just caused by a hunting-centric environment where females couldn't provision themselves and had to compete more for males.

I guess one additional step might be particularly difficult hunting. If the environment was harsh and females needed to compete for good hunters then the more difficult the hunting was the fewer males could adequately provision and the stiffer the competition.

So that seems to imply the Eskimo or Bushman environment might be harsh and hunting-centric but the hunting itself might be relatively easy? Or maybe not easy exactly but consistent? Or just more short distance?

Which of course does lead to

"If we look at Arctic hunter-gatherers in general, the operational sex ratio is most lopsided where the men have to pursue game animals on foot over long distances."

So a higher death rate does make sense. My bad.

The same selective pressure might effect IQ and (sudden thought) possibly also a height thing? Long-distance -> longer limbs?

So operational sex ratio ~ IQ and height?

.
"We do in fact see non-black hair and non-brown eyes among the Eskimos of the northwestern Canadian Arctic...may be an early stage of the same evolutionary trajectory that early Europeans went through."

Ah interesting. I wonder if hunting is harder / more long distance / higher death rate in those regions compared to other eskimo regions?

.
"These two factors become important when men are presented with an abundance of female candidates who are otherwise equal in quality."

I guess if the initial pressure improves the average quality then novelty could then become the deciding factor.

I read somewhere, i forget where, that long *light* hair would show youth better or trick the eye into seeing youth better (where youth ~ fertility).

Not sure if that is correct?

Stephen said...

Cochran could actually almost have a plausible hypothesis there. Rare hair and eye colors could be seen as magical. So they would be more likely to make a living as traveling shamans spreading their genes about having affairs with the cave women while all the hunters are out. Im glad the date has been pushed back as I have difficulty imagining cromagnons as dark skinned for some reason. Another reason could be more feminine features are seen as less threatening, thus you more likely to establish a trading relationship rather than killing them on first encounter. Multiple selection hypothesis could be true at the same time.

tyrionlannister69 said...

Peter Frost,

I am not convinced by your argument, sexual preferences for novel features seem more like side-effects of modes of sensory organ and nervous system functioning. Although novelty of the stimuli could account for preferences for motorcycles and automobiles, it could not explain preferences for mating. People have a preference for "averageness" per se,( independent of familiarity, novelty, etc) when judging the attractiveness, which may reflect a preference for signals of quality. According to koinophilia, when an individual seek a mate, they prefer that mate not to have any unusual, peculiar or deviant features. Natural selection results, over the course of generations, in beneficial (or fit) features replacing their disadvantageous counterparts. Thus, natural selection causes beneficial features to become increasingly more common with each generation, while the disadvantageous features become increasingly rare.

In evolutionary biology, a reliable criterion for adaptiveness is a special design, which means that a trait is constructed in such a way that it is difficult to deny that the trait was evolutionarily shaped to perform a given function. Colour features can not regarded as evolutionary adaptations that direct an observer toward individuals of high mate value, i.e., individuals possessing genes that determine high biological quality (so-called good genes), and having desirable phenotypic (biological and psychological) trait. There are not patterns of colour features obtained in empirical studies and explained in terms of biological adaptations and regarded as functional. I understand you can think up a functional explanation for virtually every possible model of sexual selection, so one needs a more solid methodology of drawing and testing functional/ adaptive explanations of empirically found physical perception than so-called “story telling”.

A theory seems more credible if it correctly predicts some phenomena instead of being post hoc. As regards colour features hypothesis, one general prediction would be that there should be a correlation between determinants of traits and the quality of her/his owner. Neither a correlation of a physical trait with a component of fitness proves the adaptiveness of a preference for the trait, because such correlation may be produced by several other mechanisms. Nothing is known about the underlying fitness correlates of these physical colour traits in traditional settings (e.g., do oestrogenic profiles covary with colour hair, eyes or skin?). Even less is known about the precise proximate mechanisms that generate them and the factors to which they are sensitive (e.g., does mutation load or pathogen resistance affect features?). The functionality of colored features and white skin preferences should be also testified by cross-region and cross-modality correlations of attractiveness. (Specifically, people with bright and beautiful colours and light tone skin should also have high facial attractiveness, attractive body and voices, and their smell should be nice?).

Anonymous said...

Yes, there is a strong trend for hair color to be darker than skin color (the reverse is very rare in humans). I suspect that dark head hair enhances the relative lightness of facial skin.

Then how did light hair evolve? Again, there are several factors at work here, one of them being the "novelty effect." There seems to be sexual selection for female hair color on the basis of novelty, i.e., the rarer the hair color, the more it appeals to men. A strong novelty effect would overwhelm other factors until the rare hair color ceases to be rare.


I would have guessed that it was perhaps merely due to sexual selection not favoring feminine females (i.e. high contrast between skin and eye and hair darkness) so much as on attractively eye catching females (even though this is not in the direction of pigmental femininity).

Why this would be the case in Europe (sexual selection for generalised attractiveness in females, rather than feminine attractiveness in females), I am not sure though.

Sean said...

"In any case, the depigmentation of European skin doesn't explain the changes to European hair and eye color, which are qualitatively different. The latter changes involve different genes and a proliferation of new alleles (as opposed to a replacement of one allele by another)."

Co-existing diversity of designs shows the selection pressure is from inter-specific competition for novel appearance.

If the selection pressure was an side effect of adaptation to vitamin D photoproduction it certainly would not sustain a highly maladaptive hair colour. Pheomelanin, associated with red and golden hair, causes cancer in the absence of UV or sun exposure. See here, here and newspaper article here.

But fair skinned people, like redheads, have more vitamin D production for a given amount of sun? No, they have lower vitamin d production for the same sun exposure here, and BBC Fair-skinned people may need extra vitamin D: "...people with fair skin do not seem to be able to get enough, according to Prof Julia Newton-Bishop and her team at the University of Leeds [...] But some fair-skinned individuals also appear to be less able to make and process vitamin D in the body, regardless of how long they sit in the sun for."

szopeno said...

"I think the Frost model makes a prediction: European women will not only be more colorful, but they will be more masculine in their interests than women of other ethnic origins"

But males do not prefer more masculine females, with which they can talk about their spears. They prefer feminine females, who can cook. So I would think the prediction should be opposite: European females should be more FEMININE in psychological traits.

Fortunately, this is easily tested hypothesis. It's enough to check whether modern males marry more often masculine females, or feminine females.

Paragon said...

@Peter,

These hunting–gathering populations were evolved in multimale (low polygynous) bands, rather than monogamous system, where extended-family compounds were the main socioeconomic unit. Polygyny was the rule rather than the exception; a high variance in the males’ offspring numbers is a necessary consequence of that mating system. Even under those drastic conditions, although the operational sex ratio was female-based, some men made a large contribution to the next generation’s gene pool, and some did not contribute at all. Note that the number of offspring per male could be also variable. Male effective population sizes increased later, and therefore, over much of human prehistory, the fact that females are the (reproductively) rate-limiting sex has always manifested in their higher selectivity.

It appears, strongly, that the enabling mechanism has something to do with excess male deaths and reduced capability of men to support multiple wives, but it is naïve to believe that sexual selection basically acted on women alone. An imbalance between the proportions of men and women in the population creates an opportunity for stronger sexual selection. Sexual selection is expected to act more strongly on the surplus sex because there are fewer potential partners of the opposite sex for them.

A likely moment for the shift to monogamy is difficult to define exactly, but within their confidence interval, namely, between 10,000 and 5000 years ago in Europe and Asia and more recently in Africa and in the Americas, a major change is documented in the archaeological record, i.e., the development of technologies for farming and animal breeding, or Neolithic transition. Then nuclear families and the household replaced these extended-family bands and monogamy may have become wide-spread. Sociobiological studies do suggest that the development of extensive farming resulted in a decrease in the levels of polygyny, although those levels did not appear to be very high among hunters and gatherers either.


By the other hand, hunting large game was not necessarily an individual issue but usually a group issue, and within any group of successful males, each of whom is capable of taking care of a wife and children, women will still find some men more desirable than others. Then we have to consider the extra-pair copulation issue within this scenario. Hence, women cheating on their partner with a higher quality man do not necessarily have a partner that is a failure with respect to resource provisioning. If a woman had a male partner who could not provide her with enough resources, and she managed to get pregnant by a higher quality man who couldn’t be bothered taking care of his illegitimate children, she still has options to attempt to take care of her children: function as a servant to more successful people, serve as a prostitute, etc. Moreover these hunting–gathering bands had communal care available, therefore biparental care less crucial, paternal care is less important because of reduced costs of male abandonment; hence, pair-bonds may be unstable. Women naturally being more circumspect with their choices, even if their choices are limited, will be sexually selecting men also, in the form of cheating on their partner in some cases, if necessary. sexual selection still works in the scenarios where namely less attractive women being loser with their sexuality to get impregnated by men who would be willing to have sex with them but not take them as wives, or women offering their services as concubines or servants to feed their illegitimate children since the advantage is with the more attractive women

Paragon said...

Moreover, from a genetic standpoint, a fall in the mean number of deleterious mutations in the genome of the population and a rise in the percentage zygote survival is more marked in polygamous than monogamous mating systems. A polygamous pattern in which females mate with a minority of males has the most marked effect in reducing the number of deleterious mutations in the next generation. If environmental mutagenesis falls then the number of eligible males tend to increase and a human population can change from a polygamous to a monogamous pattern of mating. Sexual attraction is a force which counteracts genomic degradation.

Sean said...

"Thus, limited polygyny, combined with higher hunting-related mortality, skewed the mate market towards a shortage of available men. Women had to compete for men, unlike the situation among tropical humans"

I think it's worth mentioning that 'women had to compete for men', but only on average; those individual women with the eye catching characteristics of hair and eye colour in addition to other sought after traits, would be able to choose from a number of suitors.

The teleonomic function of eye-catching hair colour would be to restore choice to the individual woman, whereby requisite characteristics conferred selection of (surviving) males for their mate quality.

Paragon said...

“In other words, I think the Frost model makes a prediction: European women will not only be more colorful, but they will be more masculine in their interests than women of other ethnic origins. We might further expect that the women would then pass such traits onto their sons, resulting in more masculine men, as well. This is a question worth asking - do Europeans, and particularly European women, have more male stereotypical interests and behaviors than other populations?”

First, It makes no sense selecting among women who are willing to indulge in more extreme/disinhibited sex practices. In mate systems where males invest parentally, selection should favour paternity probability mechanism is valuation of chastity in a potential female mate. Male who preferred chaste females in a environment of evolutionary adaptedness, enjoyed greater reproductive success than males who were indifferent to the sexual contact that a potential mate had with other males. Chastity of a potential mate would provide a cue of paternity confidence. Assuming some temporal stability to behavioural proclivities, chastity would also provide a cue to the future fidelity of a selected mate. A male failing to express such a preference would risk to wasting the time an effort involved in courtship and would risk investing in offspring that were not own. And also men are attracted to signs of nulliparity. (One reason is because men are interested in the property of female fertility; men want to father all their children).

By the other hand " Primitive man's sex life was free of perversions and hang-ups "
http://akinokure.blogspot.com.es/2013/03/primitive-mans-sex-life-was-free-of.html


The strong selection pressure for female sex worked along a neotenous shape vector and dimorphism vector. Therefore north european women evolved a lighter skin colour, more feminine appearance and a more childlike physique as a means to increase male care-taking behaviour.
Women with high sex drive are inclined toward greater promiscuity and most of promiscuous women tend to have higher testosterone levels (Cashdan, 1995; van Anders, Hamilton, & Watson, 2007) and a more masculine physical appearance than average (Mikach & Bailey, 1999; Ostovich & Sabini, 2004). Therefore, most feminine women are less willing to participate in disinhibited sex practices. And elevated testosterone levels in women correlate with a greater number of sex partners and also with requiring less commitment from a man before engaging in sex.

Even if we assume that you could find a highly feminine woman with a high sex drive, testosterone or other hormone levels are not the only factors affecting sex drive. There are many other factors. If libido increases with higher levels of testosterone, factor 1, factor 2, …, factor n, then you can have high libido with low testosterone levels if other factors are present at high levels.

Promiscuity of north European women is a fallacy:
http://racehist.blogspot.com.es/2010/02/stereotype-of-swedish-women-as.html
"Stereotype of Swedish women as promiscuous"

Anonymous said...

A likely moment for the shift to monogamy is difficult to define exactly, but within their confidence interval, namely, between 10,000 and 5000 years ago in Europe and Asia and more recently in Africa and in the Americas, a major change is documented in the archaeological record, i.e., the development of technologies for farming and animal breeding, or Neolithic transition. Then nuclear families and the household replaced these extended-family bands and monogamy may have become wide-spread. Sociobiological studies do suggest that the development of extensive farming resulted in a decrease in the levels of polygyny, although those levels did not appear to be very high among hunters and gatherers either.

I don't think this is true.

Monogamy was probably just more formalized via religion, culture, politics, etc. with the Neolithic transition in areas where there was already a tendency towards monogamy or less polygyny among the pre-Neolithic.

If anything, without formal restrictions, agriculture should enable greater polygyny because it dramatically increases the available calories.

The formation and the expansion of the Bantus, a highly polygynous group, is associated with the development of agriculture in Africa. They displaced the less polygynous hunter-gatherers.

Pamela said...

Paragon noted:

"Women with high sex drive are inclined toward greater promiscuity and most of promiscuous women tend to have higher testosterone levels (Cashdan, 1995; van Anders, Hamilton, & Watson, 2007) and a more masculine physical appearance than average (Mikach & Bailey, 1999; Ostovich & Sabini, 2004). Therefore, most feminine women are less willing to participate in disinhibited sex practices. And elevated testosterone levels in women correlate with a greater number of sex partners and also with requiring less commitment from a man before engaging in sex."

First, it is not necessarily the case that a high sex drive among women leads to promiscuity. Positing a monogamous behavior pattern, it's entirely possible (and seemingly evident) that women could have a high sex drive within a monogamous relationship. This appears to be the case with women of European origin as a recent study has shown that they have the highest sex drive of all groups of women, yet their cultures are not historically polygamous:

http://majorityrights.com/images/uploads/sex_differences_BBC.pdf

(You say yourself that the promiscuity of Northern European women is a fallacy-- and I would agree-- but this does not limit the possibility of a high sex drive among such women.)

Second, there are different types of testosterone. Free testosterone governs the secondary sex characteristics that make women appear more or less feminine. High free testosterone levels lessen feminine appearance. However, other forms of testosterone govern behaviors. Women of European origin have lower free testosterone levels (hence, more feminine appearance), but higher levels of other testosterone (hence, more masculine behavior). Please see page 182 of Peter's treatise with citations to studies of female sex hormone levels:

http://137.140.1.71/jsec/articles/volume2/issue4/NEEPSfrost.pdf

Paragon said...

@Anonymous,

"I don't think this is true. Monogamy was probably just more formalized via religion, culture, politics, etc. with the Neolithic transition in areas where there was already a tendency towards monogamy or less polygyny among the pre-Neolithic. If anything, without formal restrictions, agriculture should enable greater polygyny because it dramatically increases the available calories.The formation and the expansion of the Bantus, a highly polygynous group, is associated with the development of agriculture in Africa. They displaced the less polygynous hunter-gatherers."


I would rather look at reliable and consistent parameters as molecular genetic data contain phylogenetic information the history of populations.The key is the genetic evidence for effective population sizes of human females and males (effective breeding population). In studies of Y-chromosome SNPs in Europeans has been detected wide evidence of prehistoric demographic expansions in the mitochondrial diversity of most human.

The results of SNPs analyses can be reconciled with the expansion of male effective population sizes inferred from STR loci, and with mitochondrial evidence, by admitting that humans were essentially polygynous during much of their history. As a consequence, until recently only a few men may have contributed a large fraction of the Y-chromosome pool at every generation. The number of breeding males may have increased, and the variance of their reproductive success may have decreased, through a recent shift from polygyny to monogamy, which is supported by ethnological data and possibly accompanied the shift from mobile to sedentary communities. [See Dupanloup et al 2003].

The change from a typically polygynic social structure to one in which more males had access to reproduction is between 10,000 and 5000 years ago in Europe and Asia [see Pritchard et at (1999)]. It happened about the Neolithic transition, when the development of technologies for farming and animal breeding, or [Cavalli-Sforza et al. (1994); Bellwood (2001)]

Paragon said...

@Pamela,

“First, it is not necessarily the case that a high sex drive among women leads to promiscuity.”

It seems that you want to ignore the evidence. Like I explained in an earlier post, the female inclination for sex outside of committed relationships is correlated with sex drive [See Baumeister 2004, Cashdan, 1995; van Anders, Hamilton, & Watson, 2007, Mikach & Bailey, 1999; Ostovich & Sabini, 2004]. You have a lot of studies relating female sociosexual orientation to sex drive, where the higher the sex drive the less restricted the sociosexual orientation, or interest in sex outside of committed relationships. Of course several social and cultural factors have also been observed to influence sexual behaviour too.

Sociosexuality in women is positively correlated with two measures of prenatal exposure to androgens: a) right digit ratio and hip-to-waist ratio, and b) scores on the Vandenberg Mental Rotation test, providing some limited support to the virilization hypothesis of female promiscuity. (Clard et al 2005)

Women who have high sexual arousal and sociosexuality, tend to have higher testosterone levels.[ i.e. Many porn stars have high-testosterone “masculinized” features, higher waist-to-hip ratio (more tubular shape), flatter backside, and stronger and more prominent jawline. (E. Holland 2009)].

Therefore masculinization (physical and neurophysiological) tends correlatively to increase disinhibition, promiscuity and interest in atypical sex practices (anal sex, fellatio, facial ejaculations, etc).

“Positing a monogamous behavior pattern, it's entirely possible (and seemingly evident) that women could have a high sex drive within a monogamous relationship”

Yes, in the case of an individual only careful examination will tell, but if we separate random women into more masculine and more feminine groups, then we could say with confidence that the greater.

I said above that testosterone or other hormone levels are not the only factors affecting sex drive. There are many other factors, so you can have high libido with low testosterone levels (highly feminine morphology) if other factors are present at high levels. The relationship between testosterone and libido/promiscuity is of a statistical nature, as I explained above. It is possible that the woman’s libido/promiscuity is not related to the increased masculinization but some other factor because libido is affected by many factors. Promiscuity/sex drive of the more masculine group is related to the greater masculinization.

“Women of European origin have lower free testosterone levels (hence, more feminine appearance), but higher levels of other testosterone (hence, more masculine behavior)”

Ratings of femininity, attractiveness and perceived health are strongly correlated higher estradiol levels [Law Smith et al (2005)]. Both androgens and estrogens affect various skeletal structures and soft tissues in different ways. Therefore, an examination of overall physical appearance allows one to compare the ratios of testosterone (a major androgen) to estradiol (a major oestrogen) that female of the same ethnic group have developed under. (i.e., a woman with broad shoulders and a narrow pelvis is more masculinized than average woman.)

Note that since sex hormones are only partly responsible for trait variation, it is necessary to consider a cluster of traits known to be influenced by sex hormones to assess the masculinity-femininity of a woman.

The development of most biological traits is dependent on both genes and environment, and an essential question to be answered is their relative contributions to the variation of the trait under consideration. Most studies suggest that both femininity morphological and neurophysiological depend on an individual’s sex hormone levels: Women with high level of oestrogen (and, to a lesser degree, progesterone level) have more feminine and physical appearance and behaviors.

Tyrion Lanister said...

@Pamela,

“This appears to be the case with women of European origin as a recent study has shown that they have the highest sex drive of all groups of women, yet their cultures are not historically polygamous:”

Thanks for the Paper. Anyway you oversimplify a complex subject because there would have to isolate the hormonal variable for drawing a reliable finding, but unfortunately many other factors have influence. The inter-population and within-population variation of sociosexuality is not only related to hormone levels, so it depends on several factors: a) genetic variation in female fitness, b) differential valuation of men’s phenotypic quality, c) overall variation in women’s mating strategies and d) environmental and ecological factors (population density, operational sex ratio,etc) f) genetic heritability of promiscuity/sex drive.

By the other hand, the female sociosexual variation is maintained via frequency-dependent selection. By this account, women with unrestricted versus restricted approaches to casual sex have specialized to exploit different niches [Gangestad and Simpson (1990)]. Furthermore, the value of pursuing each strategy plausibly depends on the relative frequency of women who also pursue it. Consistent with this hypothesis, female sociosexuality appears to be moderately heritable (Bailey et al). The likelihood of strategic heritable variation is controversial, however, because recombination prevents fortuitous combinations of genes from persisting long enough for polygenic morphs to evolve (Tooby & Cosmides 1990a). A two-strategy system with a binary genetic switch can evolve more easily. Such a system implies that restricted and unrestricted strategies should be typologically distinct, but this has not yet been demonstrated.

“but this does not limit the possibility of a high sex drive among such women”

It might be possible, It would be necessary to explain if there are two different dimensional matrix affecting oppositely to morphological and behavioural ontogenic vectors in the development of neuronal features and female aesthetic features. It not seem plausible because according to the effects of sex hormones the directionality of ontogeny would operate synergistic a same in one dimensional vector.

Peter Fros_ said...

Paragon,

"The change from a typically polygynic social structure to one in which more males had access to reproduction is between 10,000 and 5000 years ago in Europe and Asia [see Pritchard et at (1999)]. It happened about the Neolithic transition, when the development of technologies for farming and animal breeding"

You have it backwards. Agriculture made polygyny less costly for men by making it easier for women to feed themselves and their children with less male assistance. In Africa, high polygyny rates are associated with farming societies. African hunter-gatherers (Khoisans, pygmies) are much less polygynous, the rate being typically less than 10% of all sexual unions.

Sean said...

Sexual responsiveness in the context of an enduring monogamous sexual relationship (the adaptation known as love) would have been highly adaptive for both women and men in the steppe-tundra scenario. I don't think it was just women's proclivities that caused traditional European societies to be historically monogamous.

Anonymous said...

Sean
"Sexual responsiveness in the context of an enduring monogamous sexual relationship (the adaptation known as love) would have been highly adaptive for both women and men in the steppe-tundra scenario."

Quite. Monogamy simply makes sense in a hunting-centric environment where a man can't feed multiple sets of children. Calories dictate that it's either that or treat the children as communal. (Or a bit of both.)

(When i say hunting-centric i mean environments where calories *must* come from hunting because enough gatherable calories aren't available otherwise.

Some environments do have enough gatherable calories but meat is preferred in which case hunting is more of display than required and the resulting culture somewhere between hunting-centric and gathering-centric.)

Anonymous said...

In 2007, Greg Cochran was against my hypothesis, and his opinion counts for a lot (especially in HBD circles). I don't mind him having an alternate hypothesis. That's normal. What's abnormal is the nature of his "criticisms" -- which are high on ridicule and low on substance. It's almost as if I had said his wife wears army boots.

Cochran is a Scottish name. Maybe he's just alpha-ing you like those Scotch-Irish boys did when you were in school.

Sean said...

In the steppe tundra scenario (and almost all of subsequent history) female promiscuity would be unfeasible. Embarking on a sexual relationship meant the birth of an infant, thereby requiring (and therefore inducing) a father to stay with the woman and child to provision them. Instincts would be for monogamy in those circumstances, not in the social environment which exists in the modern west--where it's no longer considered normal to settle down with the first partner. It's quite possible that European ancestral hereditary predispositions could produce the opposite of monogamy, in the WEIRD modern social environment.

I suppose some at Peter's 'school of hard knocks' thought his middle class manners funny, but were friendly to him because they were looking for allies.

Anonymous said...

Cochran is a Scottish name. Maybe he's just alpha-ing you like those Scotch-Irish boys did when you were in school.

Cochran's hardly alpha. More of an alienating bully, troll and narcissist who attempts to implicitly compare himself to various arrogant men of genius and throws away opportunity after opportunity to persuade people in favor of ad homs.

He's smart, knows more about his field than most anyone in it (probably so he can troll others in arguments), so worth engaging, but its hardly behavior that helps establish social rank.

Anonymous said...

Cochran's hardly alpha. More of an alienating bully, troll and narcissist who attempts to implicitly compare himself to various arrogant men of genius and throws away opportunity after opportunity to persuade people in favor of ad homs.

That's alpha behavior.

It sounds like Cochran alpha'd you.

Sean said...

wasOracular dismissal of hypothesis based on.... what? Are we supposed to assume the verdict is based on complete understanding. Knowing everything would enable inductive reasoning when only and all the relevant and accurate information is available, it isn't; the originator of the hypothesis is not a serious thinker?

Euro And Not Proud! (but sober and realistic) said...

"Of all humans, male and female, European women have the whitest skin"

Its a curse. Our blue veins show through, as do our stretch marks. We hit our walls young, fast and hard. Our beauty as a shelf life which expires by our late 20 latest.

We look 60 at 40 and start to wrinkle before we even hit 30.

I don't even think our wide range of eye or hair color makes up for that mess.

I'd much rather have one hair and one eye color than have the thin, transclucent, ever aging skin that I have been cursed by birth with.

And oh, our lips. Did I say our lips are thin and practically non-existent by 40?

Not. Sexy.

The good side to all this is that we realize the fleeting nature of beauty and become much more sober and grounded about the dualities inherent in am embodied existence much earlier than our more physically blessed human compatriots.


JayMan said...

Razib Khan wrote a post that questions (in an exploratory sense) a lot of this theory.

Heather said...

Infanticide, not (just) sex selection.

In the harsh environments, people tend to kill excess babies. If women aren't necessary for food production, then they will just be extra mouths. A prettier baby is more likely to be spared by its parents and kept around than an ugly one.
Note that blue eyes are a baby trait--both of my brown-eyed sons had light grey eyes at birth.

kelechukwu said...

there is no comparison between men and female morality.

Anonymous said...

European myth is larded with tales of exceptional fertile females being swept off their feet and carried away to mate afar.

Bride snatching is normative in the ancient age. While slavery is its modern echo.

Because of the high risks involved (for the raiders) a bride raid would ONLY be done because the pressure was on. And with success, the target female would be certainly put to maximum reproductive duty, having an entirely out sized impact on the next generation.

The legacies/ myths inform us that it was for the Fair Haired Maiden that the raid was launched.

Rumpelstiltskin, the tale, is but an echo of such dynamics. His blonde hostage is put to work in the classic feminine role: spinning yarn. Further back, she would've been forced to thresh -- of which the tale alludes to.

At its core, the fable tells of the grief that a young bride felt when set to the grinding stone -- and a much older husband of whom she must serve.

The tower being iconic for her marriage obligations.

===

All such raids must feature snatches of the best of the sisters -- thence hauled across the plains -- and knocked up silly. Failing that, the raiders died.

Kidnapping the beauties and killing the rest is so normative that it's recorded from death camps (Mengele selected XX for beauty) to Turkish raiding parties. into Ukraine.

Striking hair/ eyes/ skin would've literally been a life saver for such a young woman. Given thousands of years, countless horny sex starved warriors, it's reasonable to assume that the 'natural selection' was prompt and violent.

JayMan said...

On this point, there's a new paper on alleles that contribute to skin color and their divergence across Eurasian populations, discussed on Razib Khan.

I figured you'd like to take a look at it:

Selection happens; but where, when, and why? - Gene Expression