Monday, June 30, 2008

Synteny   posted by Razib @ 6/30/2008 08:04:00 PM

PZ Myers outlines synteny. RPM says he's kind of wrong. Check out the definition in Wikipedia. Since RPM came down on me for confusion on this term I knew he would bring this up. I don't really care much about which definition is "correct," but I thought I'd point interested readers to the debate.....


Your generation was more into sexualizing young girls   posted by agnostic @ 6/30/2008 04:29:00 AM

Remember that better time when college coeds frolicked on the quad lawn, safe from the eyes of older males, who were drawn instead to the allure of a mature woman? Indeed, doesn't it seem like nowadays, in our Girls Gone Wild culture, we shove females into the sexual spotlight at ever younger ages? That's what you'd conclude from the 50,000 alarmist results that a Google search for "+sexualizing +young" returns, in particular the recent panic over 15 year-old Miley Cyrus posing semi-topless for Vanity Fair. The cropped picture to the left is of Elizabeth Ann Roberts, who was 16 when she was photographed nude as Playboy Playmate of the Month -- of January 1958.

On an intuitive level, though, we know that the culture must be more hostile than before to sexualizing young females -- there would be no hysteria if it were acceptable. Plus, suburban housewives and city-dwelling cougars have never hogged so much of our attention. Still, let's turn to three datasets that show the trend is, if anything, toward sexualizing increasingly older females in popular culture. We will look at data across the decades on beauty pageant winners, girls featured in nude magazines, and hardcore porn actresses.

First, take the winners of the Miss America beauty pageant, a competition determined mostly by how closely the contestant fits the ideal look of the time. A writer for the website Seduction Labs has already done an extensive analysis, so I took the age data from his work. Here is how Miss America's age has changed over the decades:

It sure looks like Miss America is getting older -- the ones from before 1940 are quite young -- and this is true: Kendall's tau for the correlation between year and age is +0.50 (p = 3 x 10^(-10), two-tailed). Admittedly, estimating the youth-obsession of each year with only one data-point -- the winner from that year -- is less desirable than averaging all contestants' ages for that year, but the data are hard enough to come by that this is the best we can do.

Next, consider the Playboy Playmates of the Month, averaged for a given year. While the 1950s had fewer data, each year still had at least 7 data-points. Using 12 data-points to estimate each year should make us more confident in the results, shown here:

Again, the average Playboy Playmate is getting older: Kendall's tau for the correlation between year and age is +0.44 (p = 3 x 10^(-6), two-tailed). The trend is clearly not linear, though, since there was a decrease in age at least from the mid-1950s, when the data begin, throughout the 1960s.

In response to a criticism brought up in the comments to the post showing that the popularity of blonds is recent, I've also calculated Kendall's tau based on the raw month-by-month data-points, rather than yearly averages: it is +0.18 (p = 1 x 10^(-10), two-tailed). As I mentioned to the commenter, I think it's more instructive to look at the year's average since the Playboy people likely have a target girl in mind for the year's subscription, based on the perceived demand. That is, the Playmates within a given year are comparable to the Miss America contestants for a given year -- they are chosen to fill out a year's run, and Miss April could just as well have been Miss December. Still, even by this perhaps overly stringent standard, the trend is positive and significant.

Finally, we look at actresses in hardcore porn movies. Collecting a representative sample of active females in a given year would be incredibly arduous, so instead I took famous actresses and determined how old they were when they made their first movie, and entered this as a data-point for the year in which they started making movies.

The lists I used are the AVN Hall of Fame, the XRCO Hall of Fame (which barely added anyone else), and a list of female porn stars by decade drawn up by the porn geeks at Wikipedia. I required each year to have at least 5 data-points; if there were too few, I merged that year's data with an adjacent year (whichever had fewer data-points than the other choice), so that the data-sparse year is excluded and the beefed-up year is included. This mostly affects the 1970s and early 1980s. Here are the ages of first-time porn stars by year of their first movie:

There is no increase or decrease over time: Kendall's tau for the correlation between year and age is nowhere near significance. There are several apparent upward and downward trends, though. This might be the only example of the 1980s and early 1990s showing greater progress by the declinists' standards. I recently analyzed a large, representative sample of porn stars and found that their average age is 23, for what it's worth. Again, that's what we really want to see: the age of the typical actress for a given year.

Maybe girls enter at earlier ages in recent times but don't reach their peak in popularity until they are in their early 20s. Another drawback of looking at age at first movie is that it ignores the recent popularity of "MILF" actresses -- maybe it's just that the variance in age is increasing. Admittedly, these pornstar data are not ideal.

Finally, we examine the popularity of beauty pageants specifically for teenage contestants. While I don't have datasets to analyze, such as the annual TV ratings, there is enough information on them to get a rough picture. First, there is Miss Teen USA, the adolescent version of Miss Universe. It was created in 1983, reached its peak for ratings in 1988, and has declined in popularity afterward, to the point where it may not even be televised anymore. And second, there is Miss Teenage America, which was created in 1962 and was last televised in 1977. Judging by its corporate sponsorship and celebrity hosts, it must have been somewhat popular. There are other beauty pageants for teenagers, but they are not even televised, and so do not count as evidence of an obsession with youth. Rather, we see a shift away from throwing young girls into the purely sexual spotlight.

Since there are no huge long-term swings up and down in these data, as opposed to the cases of sluttiness and violence, all generations can say that they've improved over previous generations, or at least done no worse. If any generation is to be accused of sexualizing younger girls in popular culture, though, it is surely the older ones. It is true that the current culture does not value women over 30, but that has never been the case -- just the opposite.

As with sluttiness, part of the declinists' misperception may be due to fashion trends, such as even prepubescent girls wearing adult-inspired clothing. That's hardly evidence of their being sexualized, though -- no guy is actually looking at them as a sex object, and dressing like an adult doesn't make you behave like one sexually. While it may be a bizarre fashion trend -- though more bizarre than when pre-pubescents started wearing two-piece bathing suits? -- it doesn't reflect a sexualization of the young.

What's causing this trend toward older sex symbols? Oh, I don't know, but I'm sure we'll get a bunch of half-baked ideas in the comments, so I'll get the goofball ball rolling. Women are having their first kid later, if at all, so there's a wider age range of females who haven't ruined their figure by giving birth. Still, according to the analysis of Miss America winners at Seduction Labs, there are other trends: starting around 1960, winners became taller, less buxom, and less hourglass in shape, in addition to older. In short, the feminine ideal in popular culture has been worn down by the march of the masculine minxes. It's a mistake to blame this on the women's movement of the 1970s, though, since most of these trends began in the early-to-mid-1960s. Radical feminists were just jumping on the bandwagon and trying to steal credit for it.

Though it's harder to measure, the manliness of these sex symbols' faces has surely increased -- go back and look at some of the Playboy Playmates from the late 1950s through the late 1960s. They look like girls, not butch transvestites (NSFW, obviously). I see this as a form of cultural decline, of course, but the declinists who decry our obsession with youth could not be more wrong.

Labels: ,

Increased rates of sexually transmitted diseases amongst the older   posted by Razib @ 6/30/2008 01:55:00 AM

Doubling Of Sexually Transmitted Infections Among Over-45s In Under A Decade. Dare we say an "epidemic???" If you want to push the envelope of course, She was 82. He was 95. They had dementia. They fell in love. And then they started having sex. In any case:
While the numbers of infections identified in younger age groups rose 97% during the period of the study, those identified in the over 45s rose 127%.
"Indeed, it may be argued that older people are more susceptible [to sexually transmitted infections] as they are less likely to use condoms than younger people," they say, adding that as successive waves of people with more liberal sexual attitudes and behaviours age, the problem is likely to worsen.

I guess the "safe sex" message just isn't getting through to the less young.

Related: Your generation was sluttier.

Labels: ,

Sunday, June 29, 2008

Bygone brunette beauty: Fashion in hair color   posted by agnostic @ 6/29/2008 05:12:00 AM

Long-time readers know that one of my beliefs that I'll stop at nothing to prove is that blond women are not sexier than brunettes, whatever other appeal they obviously have for many men. Point-estimates of the current popularity of blond hair neglect the fact that standards of beauty can change over time -- within boundaries, to be sure, but still. Perhaps we only live in a blond-obsessed world today, while brunettes may have ruled in the past. Indeed, I will show just that. Furthermore, the shift toward blonds parallels several other shifts toward a more masculine ideal of female beauty since the early / mid-1960s.

The data come from Playboy Playmates of the Month ("Playmates") from 1954 to 2007. We need to look at sources that pander to popular demand in sexual tastes, which excludes runway fashion magazines (not used by males for fantasy purposes) as well as data on high-ranking Hollywood actresses (who are esteemed only in part based on their looks). We also need comparable data that stretch over decades, and that provide us with many data-points for each year -- in a worst case scenario, we might look at something like Miss Universe winners, but estimating the value of blond-obsession for a given year with only a single data-point is hardly ideal. Playmates, though, yield 12 data-points per year.

In the name of scientific discovery, I looked at pictures of every Playmate [1], and coded her hair color as either 1 for blond or 0 for non-blond. Dark blonds counted as blond, light browns as non-blond. Redheads counted as blond if they had very fair, strawberry blond hair, and as non-blond otherwise. The point is not to measure the popularity of the full spectrum of hair colors -- just blondness. A small handful of Playmates had several hair colors within the single issue they appeared in. I coded these as 0.5 because their pictures were split pretty evenly between blond and non-blond hair -- maybe due to wigs, I don't know.

I then took the fraction of blonds in a given year and plotted these over time. Here is the raw scatter-plot, together with 3-year and 7-year moving averages that smooth it out:

The scatter-plot suggests an increasing trend, and this is true: Kendall's tau for the correlation between year and percent blond is +0.27 (p = 0.01, two-tailed). [2] However, because each year's value can only take on roughly 12 values (1 / 12, 2 / 12, etc.), there are a lot of tied years, which may underestimate the true correlation. Kendall's tau for the correlation between year and the 3-year moving average of percent blond is +0.47 (p = 2 x 10^(-6), two-tailed), and is +0.64 (p = 2 x 10^(-10), two-tailed) when the 7-year moving averages are used. Using a moving average gives us a better idea since they can take on far many more values, and so produce fewer ties.

Whichever one we choose, it is clear that blonds have increased quite a bit in popularity over the decades. At the same time, the trend is clearly not linear: there is a decrease in blond-obsession at least from the mid-1950s, when the data begin, to the early / mid-1960s. There follows an increase, and an apparent reversal since the turn of the millennium -- please god, let it be so. This looks periodic, like a fashion cycle.

In trying to account for this trend, we should try to be as general as possible. What other trends in female beauty show an increase after the early 1960s? I didn't look at other aspects of the Playmates, but someone else has tabulated data on Playmates of the Year from 1960 to 2006 -- again, estimating the popularity of some trait in a given year based on a single data-point is worst-case, but I'm relying on it here because I've already spent enough time collecting hair color data. The links in footnote 1 provide all the anthropometric data, though, so if you want to collect an analyze it, we will link to your analysis.

I calculated the Waist-to-Hip Ratio and BMI of Playmates of the Year from the above data, and Kendall's tau for the correlation between year and WHR is +0.53 (p = 4 x 10^(-7), two-tailed), while between year and BMI it is -0.24 (p = 0.02, two-tailed). So, these sex symbols are increasingly losing their feminine hourglass shape and fatty softness -- nearly all BMI points are below 20, so it's not like they used to be fat but are now healthy. They are also getting taller: Kendall's tau is +0.31 (p = 0.004); and smaller in the chest: Kendall's tau is -0.35 (p = 0.001).

Someone else has also done an analysis of Miss America winners, and the exact same trends emerge there as well (see his graphs).

The common factor of all these trends is that the ideal of female beauty has become increasingly masculinized. Recall that males are more likely to be blond, so the hair color trend is part of the larger masculinizing trend. I didn't look at eye color, but if it's part of the overall trend, the earlier Playmates should be less blue-eyed than later ones, as blue eyes are also more typical of males. Skin color would be tougher to analyze; if it's part of the same trend, it should get darker over time. Anecdotally, these two guesses seem to be true, but someone should look at the data to check.

It therefore appears that a preference for blonds should also correlate with a preference for taller and less curvy women. Again, someone else can look that up in the psychology literature and post in the comments. But the words "tall," "thin," and "blond" usually co-occur, don't they? Whatever appeal such women have, raw sex appeal is unlikely to be among the top reasons. Blond hair correlates with something like introversion, and that makes sense since men on average are more introverted than women. So, maybe guys start digging blonds when they become more marriage-minded, or if they are inveterate monogamists. A blond will be less likely to be bouncing off the walls and being constantly out and about in search of social stimulation.

Bang a brunette, bank on a blond? It would fit with the trend toward lower sluttiness in recent times, which we expect to weed out the sex kitten types from popular culture. This suggests that dark hair is part of that highly sexualized image -- something that was always obvious to everyone but the blond-lovers.

[1] For years 1954 to 1992, I used this source that contains the full shoot for each Playmate, and for 1993 to 2007, Playboy's official website (if the single picture available on the Playboy site was ambiguous, I did a Google image search to get a better idea).

[2] You can easily calculate Kendall's tau with this website, which I used here.

Labels: ,

Friday, June 27, 2008

Heritability of voting   posted by Razib @ 6/27/2008 01:44:00 PM

Genetic Variation in Political Participation:
The decision to vote has puzzled scholars for decades...The results show that a significant proportion of the variation in voting turnout can be accounted for by genes. We also replicate these results with data from the National Longitudinal Study of Adolescent Health and show that they extend to a broad class of acts of political participation. These are the first findings to suggest that humans exhibit genetic variation in their tendency to participate in political activities.

Additive genetic variance ~ 0.50. You can read the whole paper, though I've blogged it elsewhere.


A blog on Roman History & Archaeology, etc.   posted by Razib @ 6/27/2008 10:44:00 AM

Something new in my RSS over the past few weeks, PhDiva. Feel free to mention blogs of note or that you find interesting (or your own blog) in the comments....

Thursday, June 26, 2008

In Our Time, The Arab Conquests   posted by Razib @ 6/26/2008 11:59:00 AM

On this week's In Our Time they're talking about the Islamic conquests. The author of When Baghdad Ruled and The Great Arab Conquests is one of the guests, so if you meant to read the books but never got around to it for whatever reason, might be worth a listen. As I told a friend the first few centuries of the emergence of what we know as the Islamic World (650-850) are interesting, but after that point you hit a somewhat stationary state (most of the sects and schools of Islamic law emerged during this period, even if their identity only full crystallized between 850 and 1150). Details such as how Iran was transformed into a Shia state by the Safavids in the 16th century are not trivial, but they pale in contrast to the implications for world history of a new ideology & empire which stretched from the Atlantic to the Indus.


Tuesday, June 24, 2008

EDAR again   posted by p-ter @ 6/24/2008 09:00:00 PM

There have been a number of posts on this site regarding EDAR--in summary, a non-synonymous SNP has swept up to high frequency in East Asian populations via positive selection, and appears to account for some variation in hair form. The evidence for function in hair form comes largely from an association study on hair thickness. Now add a mouse model to the evidence:
We show that elevation of Edar activity in transgenic mice converts their hair phenotype to the typical East Asian morphology. The coat texture becomes coarse, with straightening and thickening of individual hairs and conversion of fiber cross-sectional profile to a circular form. These thick hair fibers are produced by enlarged hair follicles, which in turn develop from enlarged embryonic organ primordia. This work shows that the multiple differences in hair form between East Asian and other human populations can be explained by the simplest of genetic alterations.
On the right is a wild-type mouse, contrasted with the "Asian" mouse. The mechanism by which this works is kind of intriguing--apparently the substitution in EDAR leads to increased signaling via NFkB, but it's an open question (both in this case and more generally) how the modification of the activity of a transcription factor leads to phenotypic changes at the level of an organism.


Monday, June 23, 2008

Your generation was more violent   posted by agnostic @ 6/23/2008 05:08:00 PM

Previously we found that your generation was sluttier, so we turn now to another great threat to civilization -- violence (between individuals). As before, our concern is with whether violent crime rates are increasing or decreasing, and not so much with the absolute level: it is easier to screw up civilization than it is to improve on it, so a decline can quickly snowball, while it may take much longer to restore things to their previous levels.

There are very good and very clear data on violent crime, so this post will be much more direct than the one on sluttiness. Let's begin with homicide. The Bureau of Justice Statistics, part of the US Department of Justice, has taken homicide data from the CDC's National Center for Health Statistics and put it into a straightforward graph. I see five trends in the graph: an increase from 1900 to the mid-1930s, a decrease from the mid-1930s to about 1960, an increase from 1960 to the late 1970s, a fairly steady high level (with oscillations) throughout the 1980s, and a decrease from 1992 to the present.

To be generous to older generations, let's say that much of this homicide is committed by 15 year-olds. That means that the cohort born in 1945 is responsible for the increase that began in 1960. I figure you have to be about 73 years old in order to decry how violent the younger generations have been -- certainly the Boomers and Gen X-ers cannot complain, while Generation Y should be thankful they've lived through such peaceful times.

The homicide data also caution against viewing the past with rosy spectacles -- there was nothing peaceful at all about the first third of the 20th century. Declinists who long for better times in the past seem to latch onto a fleeting period of rest and prosperity. That's fine, as far as worshipping one period over another goes. However, we should not think that we can easily maintain that level, whether through individual choice or institutional incentives, as oscillations and limit cycles appear to be the rule rather than the exception. We should aim instead to have a somewhat low level of Bad Things, with low-amplitude fluctuations, and not let the mere existence of waxing and waning cause us hysteria.

What about the intersection of sex and violence -- how have forcible rape rates changed over time? Again we turn to BJS data, although they do not go back nearly as far as homicide data, the earliest year being 1960. After retrieving data from this page, looking at the entire United States, forcible rape rate, from 1960 to 2006, I put them into a simple graph:

There are only two trends here: an increase from 1963 to 1992, and a decrease afterward. In fact, the two trends look pretty linear on first glance. The slope of the increasing trend is about +1.11, and the slope of the decreasing trend is about -0.85, confirming the hunch that the decline of civilization snowballs more quickly than its restoration proceeds. As with homicide, Boomers and Gen X-ers cannot complain about rape epidemics in recent generations. This is particularly true for the Boomers and Gen X-ers who manufactured and continue to prop up the myth of the campus rape crisis.

The BJS also has an index of "violent crime" that includes murder and non-negligent manslaughter, forcible rape, robbery, and aggravated assault. I used the same search function as for the rape rate graph, and the trends for this general violent crime rate look the same as the rape rate trends, so I won't include the graph. In brief, there's an increase from 1962 to 1991, and a decrease afterward.

As in the case of sluttiness, using popular culture as a means of taking civilization's pulse is highly unreliable. Before, we saw that slutty behavior has been decreasing even as perceived slutty appearances have been increasing. Here, we see that violent crime has been decreasing even as video games, movies, and TV shows have become increasingly violent. To pick just one example, gangsta rap was invisible during the 1980s and only became popular when Dr. Dre's album The Chronic came out in 1992, drawing ever larger audiences throughout the 1990s -- at the very time when violent crime was falling.

I don't believe that trends in real behavior and in popular culture are causally related in an inverse way either -- just that they are independent of each other. Cycles of fashion in the cultural realm are self-contained, and oscillations and limit cycles in real behavior are also self-contained, at least to a first approximation. I've read posts at Cognitive Daily that exposure to violent video games (and perhaps TV shows?) desensitizes people to violence within controlled, experimental laboratory settings, and that is an interesting finding. However, in examining the world outside of the lab, violent media cannot hope to account for even a trivial share of the variance across time in violent behavior.

Labels: , ,

Comparing across American religions   posted by Razib @ 6/23/2008 01:44:00 PM

The Pew US Religious Landscape Survey has come out with its second week of survey results, now focusing in more detail on the beliefs of various groups. Nice way to compare across groups. I've collected and reformatted a selection of responses and their frequencies for four groups, Evangelicals (excluding Historically Black Churches), Mainline Protestants, Catholics and Muslims. I havd argued before that the median religious beliefs of American Muslims are closer to Evangelical Christians than to the religious as a whole. Therefore, one has to be careful when comparing "moderate Christians" to "moderate Muslims," since the former is likely to have far more liberal religious and social beliefs than the latter, though they might be appropriately termed so in the spectrum of their tradition. The results seem to suggest that I was mostly right; though American Muslims are somewhat less conservative than Evangelicals. Interestingly, note that Roman Catholics and Mainline Protestants are hard to distinguish.

(Caution: don't read that much into the percentages on the margins. 6% of atheists and 14% of agnostics believe in a Personal God according to the survey! Also, readers will probably be interested in the detailed tables which breakdown by denominations)

Evangelical Muslim Catholic Mainline Protestant
Abortion legal in all cases 9 13 16 20
Homosexuality should be accepted by society 26 27 58 56
Receives answers to prayer once a week 29 31 15 14
Attend religion service more than once a week 30 17 9 8
Own religion is one true faith leading to eternal life 36 33 16 12
Only one true way to interpret religion 41 33 19 14
Gov. should do more to protect morality 50 59 43 33
Scripture literally true word of god 59 50 23 22
Frequency of prayer 78 71 58 53
Religion very important 79 72 56 52
Belief in God: absolutely certain 90 82 72 73


Web-based Collaboration Software   posted by Razib @ 6/23/2008 12:30:00 PM


Hope for freaks   posted by Razib @ 6/23/2008 12:18:00 PM

Shyness drug could boost confidence; life might get a lot less fun for normals if this pans out.... H/T Marginal Revolution.

Sunday, June 22, 2008

Expel the 7R?   posted by Razib @ 6/22/2008 12:25:00 PM

Dan at Genetic Future, a great guy, has another DRD4 post up. He has reproduced a chart from an article in The Economist which shows a trend where a higher frequency of the 7R (ADHD correlated variant) is found in groups which have migrated a greater distance. He asks whether "the "novelty-seeking" behavior associated with ADD may have extended into a desire to explore new territories." My first thought was this: perhaps people with the 7R variant were more likely to be kicked out of the tribe or village because they couldn't/wouldn't conform. Certainly the chart seems to imply that stable populations hovering around the Malthusian limit probably aren't too congenial for nonconformists. This is the argument at the heart of books such as The Moral Consequences of Economic Growth and Age of Abundance, though obviously there wasn't a genetic perspective there.

In any case, I think there's going to be some interesting stuff coming out of this area correlating lifestyle with personality profiles. You might recall that in Farewell to Alms Greg Clark repeated the old truism that farmers tended not to be more affluent than hunter-gatherers, and in fact the balance of the data implies most hunter-gatherer and nomadic groups have a median physiological fitness that is greater than that among farmers as measured by size and nutrition as evidenced by enamel growth. The genius of farming is that it obviously increased the productivity per unit area in terms of calories and so supported larger populations (physiological fitness obviously does not translate into reproductive fitness always), but it seems to me that the less violent and risky nature of this lifestyle (famines notwithstanding) meant that there was also less room for the nonconformists on the margins. I've argued in the past in some ways theat modern individualistic Westerners have more in common with hunter-gatherers than with peasants in "traditional" societies in regards to their mores. I wonder if the need and necessity for straight-jacket social control in village life induced a powerful bout of purifying selection against 7R across much of Eurasia, a pressure that is only now being relaxed.

Addendum: The expulsion of male misfits is one of the accounts given of the founding of Greek colonies. Of course, it could simply be that the annalists used the argument that these men were misfits to get rid of them and they were actually economical marginals who were a burden upon the citizenry.

Update: I want to be clear here to note that I don't expect that all H & G societies would favor 7R more than farmers. Just that I think that the constraints of an agrarian lifestyle around the Malthusian limit would result in less tolerance of variance of behavior on the margins. The marginal slack for H & G groups I assume would be due to more frequent tribe-level extinctions, war and interpersonal violence, as well as localized ecological parameters which have a more direct impact on H & G peoples.

Related: DRD4 posts.


Saturday, June 21, 2008

Are the unchurched criminals?   posted by Razib @ 6/21/2008 09:53:00 PM

43% of young men who never go to church have a record, according to the Inductivist:
The same kind of pattern holds here. For men, 43% of those who never go to church have been arrested, while only 13% of the most frequent attenders have. The corresponding percentages for females is 14% and 8%.

The results are from the GSS. The main question I would have are the affects of the background environment; in many socially conservative environments the expectation of involvement in a church is very strong and unchurched status could be a signal for anti-social tendencies. I know whereof I speak, I grew up for a while in a 3/4 Republican 99% white region of the Mountain West and those who were unchurched were often those who were "up to no good" (a small minority were secular liberals, but only a very small minority). My own prediction would be that this would be a more common phenomenon in a very religious country like the United States.

Labels: , ,

Friday, June 20, 2008

Religion & politics of American faculty   posted by Razib @ 6/20/2008 11:46:00 PM

A post at my other weblog on a survey that came out last year. Nothing too surprising except for the disciplinary breakdowns....


The benefits of the bad: they "hit it" (males at least)   posted by Razib @ 6/20/2008 01:08:00 AM

Bad guys really do get the most girls:
But being just slightly evil could have an upside: a prolific sex life, says Peter Jonason at New Mexico State University in Las Cruces. "We have some evidence that the three traits are really the same thing and may represent a successful evolutionary strategy."
This observation seems to hold across cultures. David Schmitt of Bradley University in Peoria, Illinois, presented preliminary results at the same meeting from a survey of more than 35,000 people in 57 countries. He found a similar link between the dark triad and reproductive success in men. "It is universal across cultures for high dark triad scorers to be more active in short-term mating," Schmitt says. "They are more likely to try and poach other people's partners for a brief affair."
"They still have to explain why it hasn't spread to everyone," says Matthew Keller of the University of Colorado in Boulder. "There must be some cost of the traits." One possibility, both Keller and Jonason suggest, is that the strategy is most successful when dark triad personalities are rare. Otherwise, others would become more wary and guarded.

Frequency dependence. Control for environment and one might assume that personality morphs will hit an equilibrium in terms of relative proportion; but of course one assumes that any normal environment will be subject to exogenous shocks which jar the equilibrium on a regular basis. I wish popular science articles would bring up Hawk vs. Dove dynamics more often to introduce the general concept of variant strategies in populations. The relevance of this sort of result to recent posts should be pretty obvious, and is also one reason many people were always less than enthusiastic about Evolutionary Psychology's monomaniacal focus on human universals.


Thursday, June 19, 2008

Rapid evolution of a gene duplicate   posted by p-ter @ 6/19/2008 08:12:00 PM

One mechanism for the generation of new genes in the retrotransposition of mRNA back into the genome, creating a new, intronless copy of the parental gene. The majority of these copies, lacking proper promoters, end up as "processed pseudgenes". A neat paper recently published in PLoS Biology, however, demonstrates that a new gene generated by this mechanism in the primate lineage has actually rapidly evolved under positive selection. Strikingly, they're able to precisely track the function of the protein over time by recreating ancestral variants. From the abstract:
A microtubular CDC14B variant spawned CDC14Bretro through retroposition in the hominoid ancestor 18–25 million years ago (Mya). CDC14Bretro evolved brain-/testis-specific expression after the duplication event and experienced a short period of intense positive selection in the African ape ancestor 7-12 Mya. Using resurrected ancestral protein variants, we demonstrate that by virtue of amino acid substitutions in distinct protein regions during this time, the subcellular localization of CDC14Bretro progressively shifted from the association with microtubules (stabilizing them) to an association with the endoplasmic reticulum. CDC14Bretro evolution represents a paradigm example of rapid, selectively driven subcellular relocalization, thus revealing a novel mode for the emergence of new gene function.
Pretty cool stuff.


Dogs, behavior & genomics   posted by Razib @ 6/19/2008 12:30:00 PM

A reader pointed me to this paper, Single-Nucleotide-Polymorphism-Based Association Mapping of Dog Stereotypes:
...Analysis of other morphological stereotypes, also under extreme selection, identified many additional significant loci. Less well-documented data for behavioral stereotypes tentatively identified loci for herding, pointing, boldness, and trainability. Four significant loci were identified for longevity, a breed characteristic not under direct selection, but inversely correlated with breed size. The strengths and limitations of the approach are discussed as well as its potential to identify loci regulating the within-breed incidence of specific polygenic diseases.

I've placed an important table below the fold.


Labels: ,

Did America matter for the Industrial Revolution?   posted by Razib @ 6/19/2008 12:11:00 AM

Made in America? The New World, the Old, and the Industrial Revolution. Greg Clark is one of the authors. Robin Hanson has the summary up.


Wednesday, June 18, 2008

Genetic Relatedness   posted by Razib @ 6/18/2008 09:22:00 PM

John Hawks on what it means to be human. RPM objects to an assertion John makes about the relationship of distant cousins; worth reading. It's an interesting exploration of a subtle topic; we've covered these issues when discussing ethnic nepotism. In Narrow Roads of Gene Land W. D. Hamilton alludes to the fact that molecular and evolution biologists tend to view the central questions and answers differently for instrumental reasons.

East Asian psychometric variance   posted by Razib @ 6/18/2008 11:42:00 AM

Asian-White IQ variance from PISA results:
The NE Asians performed about .5 SD better on average (consistent with IQ test results), and exhibited similar (slightly higher) variance.

Interestingly, the Finns performed quite well on the exam, posting a very high average, but their SD is slightly smaller. The usual arguments about a (slightly) "narrow bell curve" might apply to the Finns, but apparently not to the NE Asians.

Read the whole post to see if you follow the logic of the inferences; I've done some digging on this before to spot check the Europeans-higher-variance meme and didn't find much to support it, and some data to disprove it (though you could explain away that data because of clumping of distinct populations, etc.). That's the main reason I get irritable whenever this meme pops up in the comments, it's one of those "facts" which exhibits circular citation dynamics and spreads like wildfire. Of course, it isn't as if the meme is totally emerging out of a vacuum: if East Asians are so smart why aren't they as scientifically creative??? It seems to me that the most plausible explanation has to be that individual intelligence isn't sufficient for intellectual creativity, though it is likely a necessary precondition. Some of the other variables might be rooted in individual psychology (personality), but I suspect others manifest on a larger scale (e.g., the top-down paternalism and emphasis on conformity which is the norm in most East Asia societies).

Labels: ,

Tuesday, June 17, 2008

Sheep herders are not sheep???   posted by Razib @ 6/17/2008 10:44:00 AM

Ecocultural basis of cognition: Farmers and fishermen are more holistic than herders:
It has been proposed that social interdependence fosters holistic cognition, that is, a tendency to attend to the broad perceptual and cognitive field, rather than to a focal object and its properties, and a tendency to reason in terms of relationships and similarities, rather than rules and categories. This hypothesis has been supported mostly by demonstrations showing that East Asians, who are relatively interdependent, reason and perceive in a more holistic fashion than do Westerners. We examined holistic cognitive tendencies in attention, categorization, and reasoning in three types of communities that belong to the same national, geographic, ethnic, and linguistic regions and yet vary in their degree of social interdependence: farming, fishing, and herding communities in Turkey's eastern Black Sea region. As predicted, members of farming and fishing communities, which emphasize harmonious social interdependence, exhibited greater holistic tendencies than members of herding communities, which emphasize individual decision making and foster social independence. Our findings have implications for how ecocultural factors may have lasting consequences on important aspects of cognition.

I reviewed the Richard Nisbet's Geography of Thought 5 years ago. There seems to be a substantial literature on this topic in regards to different dominant modes of cognition. There is a great deal of overlap, and these tendencies seem to be highly plastic (e.g., you can "train" someone to think in an alien mode rather quickly), but on the margins the average differences between societies have likely mattered a great deal. Would anyone, for example, claim that the individualism of the Celts vis-a-vis the Romans in their fighting styles served them well? In contrast, total nomads (as opposed to farmers who practice a great deal of animal husbandry) can arguably leverage individual action against slow moving group formations to a far greater extent (e.g., as evidenced by the shift by the Romans themselves from fixed infantry based defenses toward mobile armies during the late Empire). And of course both When Histories Collide and Farewell to Alms seem to be making the case that particular economic and social systems have fostered customs and traits which are beneficial to the flourishing of capitalism.

Labels: ,

Your generation was sluttier   posted by agnostic @ 6/17/2008 12:25:00 AM

I am sick of hearing Baby Boomers and Gen X-ers complain about a perceived cultural decline among the younger generations. For a variety of measures, things started to go bad already by the 1950s, became obscene during the 1960s and '70s, and plateaued some time during the 1980s. Since roughly 1990, however, things have gotten steadily better. This series will catalog such a trend for measures typically given in support of the declinist hypothesis: we begin with sexual behavior, and will eventually cover violent crime, divorce, narcissism, the arts, and whatever other examples I come across or that readers suggest in the comments. The hope is that the series will prevent the real-world picture from disappearing down the Memory Hole, as every generation thinks that patterns among its usurpers spell doom, regardless of what the data show.

Importantly, I am more interested in the slope or derivative of an indicator at some point in time, and less so in the value of the indicator at that point. The reason is simple: those who claim that our culture is declining, decaying, rotting, dying, and devolving are making an argument about whether some indicator is increasing or decreasing over time. What the declinists are really saying is that there are forces that cause promiscuity, say, to increase or to decrease. Therefore, even if some Bad Thing was lower in 1958 than in 2008, it may have been in a state of worsening then (increasing), and in a state of improving now (decreasing), so the underlying corrosive forces must have been stronger then and weaker now. It is the strength of these unseen "causes of decline" that I'm interested in.

Sluttiness is perhaps the most frequently given example of how far kids these days have fallen -- fallen, that is, from the zenith of innocence embodied by fucking your gf in the back of your car at Make-out Point (or the drive-in theater), round-robin pairing off during the sexual revolution, and the barely-covers-you costumes of the disco era and its spillover into the nightclub scene of the 1980s. Although there are not national probability samples (as opposed to convenience samples) going back decades for the entire diversity of perversions, indicators of sexual misbehavior correlate with each other, so we may need to rely on a proxy indicator if data are lacking for another.

The most straightforward indicator of sluttiness is simply the percentage of people who have had a "high" number of partners for their age. Since the declinists target the younger generations, let's look at the percentage of high schoolers who have had 4 or more sexual partners. Here are the data from the representative National Youth Risk Behavior Survey. From 1991 to 2007, this percentage has decreased. This is the strongest argument against the declinist hypothesis.

I could not find a good national probability sample that included a straightforward measure of sluttiness before 1991, but we can look at some proxies. The percentage of adolescents who have ever had sex is one: if you haven't had sex ever, you can't have had multiple partners, and earlier age of first intercourse is correlated with having more partners (that is not a tautology). The YRBS data above show that this indicator too has been decreasing from 1991 to 2007. Before then, we turn to a different dataset, although it is also national and representative: the National Survey of Family Growth. According to the CDC's summary:

Proportions were calculated for adolescent women in each year of age from 15 through 19 who reported having had premarital sexual intercourse by March 1 in 1970, 1975, 1980, 1985, and 1988. For all ages combined for each of these periods, the proportion of adolescent women who reported having had premarital sexual intercourse increased steadily (from 28.6% in 1970 to 51.5% in 1988 (Table 1)).

The 1988 figure of 51.5% is nearly the same as the 1991 figure of 50.8% from the YRBS data (see here, where the data are broken down by male vs. female). Thus, at least as far back as 1970 (and probably earlier), the fraction of teenagers who had had sex was already increasing, it peaked around 1990, and has been decreasing ever since.

We can also look at the spread of sexually transmitted diseases that are very common and have been around long enough for there to be decades of relevant data. First we look at gonorrhea. This table of gonorrhea rates by year shows that it increased from 1941 to 1946, decreased until 1957, increased until 1975, and decreased until 1997, leveling off thereafter. The main trends that emerge are a 20-year period of increase from the late 1950s until the mid-1970s, and a 20-year period of decrease from the mid-1970s to the mid-1990s.

A widespread campaign to treat gonorrhea began when the rate started to decrease, so some of the decreasing trend may be due to better medicine, but combined with the data on number of partners and virginity, some of it must also be due to lower promiscuity. In any case, the data do suggest an increasing trend in promiscuity starting in the late 1950s and lasting at least until the mid-1970s.

Next we look at type 2 herpes. Its prevalence has been decreasing since some time in the late 1990s, especially among adolescents (free full text here, popular journalism write-up here). It had been increasing at least from the mid-1970s to the mid-1990s. Because herpes is not treatable like gonorrhea is, it must be that more responsible sexual behavior has curbed its spread, again in particular among adolescents.

Taken together, these various indicators -- what percentage of teenagers have had "many" partners, what percentage has ever had sex, and what percentage has a common STD -- all argue for a period of cultural decline starting in the 1960s, perhaps as early as the late 1950s, which lasted until about 1990. Since then, however, our culture has been in a state of progress regarding teenage sluttiness. Thus, if any age cohort gets to brag about improving sexual mores, it is those born about 1975 or after.

Finally, note that the average female's appearance tells us nothing about the actual level or rate of increase/decrease in sluttiness. Because this is what most older people use to support the declinist hypothesis -- "young girls didn't used to wear thongs or jeans that low-cut when I was a boy!" -- it's worth emphasizing. Note also that more salacious dance practices among youngsters don't tell us anything real either, something I pointed out with a field study on my personal blog. Girls these days may give you a standing lapdance on the dancefloor, but -- although the male receiver may wish otherwise -- this doesn't mean she is going to fuck you. One plausible reason for the disconnect between appearance and reality is that appearances are largely driven by fashion, which changes for its own sake, rather than reflect underlying changes in preferences or behavior.


While oral sex is not worth looking at as a measure of sluttiness compared to intercourse-related indicators, it's worth mentioning that there is no "oral sex epidemic," as Oprah phrased it in a typically anti-male way. (The guys would refer to it as the "efflorescence of oral sex.") Nor is oral sex being substituted for intercourse, another worry in the mind of the declinists. Read the free pdf of the study here, or if you're lazy, a Newsweek editorial summarizing it. As is usual in these cases, the only thing that is epidemic here is a fear of an epidemic.

Labels: ,

Monday, June 16, 2008

Soda vs. Pop (and Coke)   posted by Razib @ 6/16/2008 09:45:00 AM

The post on soft drink terms has elicited a great deal of response (on my other blog as well). Many people want a little more granularity; well, it was brought to my attention that Google Maps based survey is up. You can vote and increase the N. I ask all American readers interested in the topic to participate (looks like it only takes Zip Codes), as it will offer us even more detail. My "blog reader surveys" usually return around 400 responses so I hope I can increase the sample size multiplicatively....

(if you have a weblog, you might want to link too!)

Sunday, June 15, 2008

More DRD4   posted by Razib @ 6/15/2008 04:58:00 PM

Since I've been posting on DRD4 a bit, a reader asked that I post this link: A gene X gene interaction between DRD2 and DRD4 is associated with conduct disorder and antisocial behavior in males. It's Open Access, so you can read the whole thing. Also, you might be interested p-ter's critique of the MAOA research program before you go whole-hog on a behavior genetic kick.


Soda vs. Pop: explanations   posted by Razib @ 6/15/2008 04:44:00 PM

Update: A Google Maps based survey is up. You can vote, so please do!

Every few years I post this map. Anyone have good explanations for some of the patterns? (e.g., what's going on around St. Louis and Milwaukee?) Larger fine-grained version below the fold. I would say that one inference that you could make is that the fact that "Soda" has penetrated the territory of "non-Soda" through either migration or cultural emulation. The concentrations in south Florida, northern Virginia and the Research Triangle are pretty good evidence of this, as well as Denver.


Thursday, June 12, 2008

Jacob's Legacy: A Genetic View of Jewish History   posted by Razib @ 6/12/2008 02:21:00 PM

At other weblog a review of Jacob's Legacy: A Genetic View of Jewish History. Nothing new for readers of this weblog, but a respectable introduction to various topics which might surprise and interest many people.


Google and cognition   posted by Razib @ 6/12/2008 12:02:00 PM

In The Atlantic Is Google Making Us Stupid?. I am obviously more positive about Google than the author of this piece; e.g., I happen to believe that "The human brain is just an outdated computer that needs a faster processor and a bigger hard drive." Additionally, I think focusing on Google is too narrow, Wikipedia for example has definitely caused some issues with me in terms of reading academic works and always wanting "links" within the text so that I get some more elucidation of a particular term or concept. In general the constant drip of data in my own life (web, books, podcasts on my shuffle while I'm in the checkout line at the supermarket) means that there are few moments of "cognitive stillness," and I do wonder if that makes an aggregate difference in being able to see over the horizon and make unexpected connections....

Wednesday, June 11, 2008

Heredity and Hope by Ruth Schwartz Cowan   posted by Herrick @ 6/11/2008 05:00:00 PM

The subtitle, The Case for Genetic Screening, seems to say it all. But Cowan comes at the topic as an historian with an interest in medical ethics. Here's how she makes her case:

1. She shows that historically the folks who came up with eugenics were different from the folks who came up with genetic screening. She is aware of the possibility of genetic fallacy, but I think she knows that people like it when their ideas flow from pure springs. She focuses on Tay-Sachs, beta-thalassemia, sickle-cell anemia, and PKU, showing that with the partial exception of sickle-cell, the drive for genetic testing came from parents whose children suffered from genetic diseases and from communities at high risk for the genetic disease. Thus, genetic screening is a bottom-up social phenomenon, not a top-down mandate. For the beta-thalassemia chapter, she spent some time on Cyprus, where the disease is relatively common, and her on-the-ground knowledge shows.

2. She shows that from a population genetics point of view there's a big difference between eugenics and genetic screening. Eugenics, she says, is a system of encouraging the fit to bear more children and perhaps discouraging or preventing the unfit from bearing children. Eugenics thus promotes 'good genes' in the population, the literal translation of eugenics. Modern genetic screening, by contrast, makes it easier for those with bad genes to bear children for two reasons. First, screening lets people with deleterious recessives find partners without such recessives, so the recessive alleles still stay in the population. Second, screening makes couples who both have the same deleterious recessive allele more willing to bear children, since they know they can abort a homozygotic recessive fetus. She actually has some decent anecdotal data on the second point. Thus, she repeatedly emphasizes that genetic screening is simultaneously "anti-eugenic" and "pro-natalist."

3. She tells a lot of human-interest stories about important firsts in genetic screening, focusing on happy endings. Given the importance of the law of small numbers, this is probably a good idea, and it's a relatively painless way for her to show how science and medicine work in the real world.

The book is exceptionally well-written, and while her history of eugenics contains few surprises, her history of the successes and failures of genetic screening was quite gripping. She also covers the basics of Mendel from scratch, so feel free to hand the book to anyone who took high-school biology. Functionally, Cowan does the same thing for genetic screening that The New Republic did for tough-on-crime policies in the 80's and 90's: Cowan does some liberal hand-wringing while telling the reader that no, you're not becoming a Brownshirt if you agree to an amnio.....

Related: Heredity and Hope: The Case for Genetic Screening by Ruth Schwartz Cowan.


DRD4, politics & friendship   posted by Razib @ 6/11/2008 12:56:00 PM

Dan points me to this working paper, Friendships Moderate an Association Between the DRD4 Gene and Political Ideology:
Studies of identical and fraternal twins suggest that political ideology has a heritable component...but no specific gene associated with...political ideology has so far been identified. Using data from the National Longitudinal Study of Adolescent Health, we investigate the moderating influence of friendships on the contribution of the 7R allele of the DRD4 gene to liberal political ideology. The number of self-nominated friendships in adolescence moderates the influence of the gene on political ideology; the more friends nominated, the stronger the liberal ideological identification of the respondent in early adulthood. This is the first study to elaborate a specific gene-environment interaction that contributes to ideological self-identification.


Related: Optimal personality and way of life. Heritability of the Ultimatum Game.


Tuesday, June 10, 2008

Lesbians opposed to lesbianism   posted by Razib @ 6/10/2008 11:11:00 AM

Lesbos islanders want to stop homosexual women calling themselves Lesbians. There's a video report by the BBC about this story, jump to 1 minute and watch as an old Greek dude expresses his proud identity as a Lesbian, at which point the interviewer asks if he's a lesbian.


Monday, June 09, 2008

Optimal personality and way of life   posted by Razib @ 6/09/2008 06:21:00 PM

Update: Here's the paper, Dopamine receptor genetic polymorphisms and body composition in undernourished pastoralists: An exploration of nutrition indices among nomadic and recently settled Ariaal men of northern Kenya. I've put the most relevant figure below the fold.

Is ADHD An Advantage For Nomadic Tribesmen?:
While those with the DRD4/7R allele were better nourished in the nomadic population, they were less well-nourished in the settled population. Although the effects of different versions of dopamine genes have already been studied in industrialized countries, very little research has been carried out in non-industrial, subsistence environments like the areas where the Ariaal live, despite the fact that such environments may be more similar to the environments where much of human genetic evolution took place.

6 years ago, In our genes:
Our hypothesis suggests that the absence of 7R in East Asia is recent, consequent to the establishment of powerful polities that allowed population growth and forced agricultural intensification. It is of interest in this context that 2R alleles in China are probably derived from 7R alleles by recombination, suggesting that the loss of 7R is indeed recent.

Besides lowland South America, another well known region with local anarchy and female farming is highland New Guinea. Our model of the dynamics of 7R predict that the frequency is very high in those populations. Because they have been there for tens of thousands of years and they have not moved, the Chen et al. (2) model predicts a low frequency of 7R there. This is a natural test to distinguish the two hypotheses. A 7R frequency of 0.25 was reported (2) for a sample from New Guinea, but it is not reported even in the original source of the data whether it was from a highland or coastal population.

In some societies 7R allele may lower fitness even when rare, as is probably the case in East Asia and among the !Kung Bushmen. In such populations it would stay rare even in the presence of gene flow from neighboring populations, even from neighbors with a social system that favors 7R alleles. Neutral genes would show no sharp boundary between the two populations, whereas alleles affecting behavior should show a sharp spatial gradient. This is likely to be the case with the 7R allele because some adjacent populations have very different 7R frequencies.

Here's a map which shows some geographic variation for the 7R repeat.

Related: Genetic Future has more.


The Wisdom of Repugnance   posted by Razib @ 6/09/2008 12:37:00 PM

Engineering Life: The Dog that Didn't Bark in the Night:
...Erwin Chargaff, an eminent Columbia University biologist, called genetic engineering "an irreversible attack on the biosphere."

"The world is given to us on loan," he warned. "We come and we go; and after a time we leave earth and air and water to others who come after us. My generation, or perhaps the one preceding mine, has been the first to engage, under the leadership of the exact sciences, in a destructive colonial warfare against nature. The future will curse us for it."

At the same time, people warned that we were doing the unnatural, something that humans were not meant to do. "We can now transform that evolutionary tree into a network," declared Robert Sinsheimer, a biologist at the University of California, Santa Cruz. "We can merge genes of most diverse origin--from plant or insect, from fungus or man as we wish."

It was not a power that Sinsheimer thought we could handle. "We are becoming creators--makers of new forms of life--creations that we cannot undo, that will live on long after us, that will evolve according to their own destiny. What are the responsibilities of creators--for our creations and for all the living world into which we bring our inventions?"


Evolution of blogs   posted by Razib @ 6/09/2008 12:19:00 AM

Since GNXP is now a little over 6 years old as of 1 week ago, I thought I would point to this short history of blogging. Most of the comments seem about right.

Sunday, June 08, 2008

IQ and Higher Education   posted by DavidB @ 6/08/2008 04:25:00 AM

Readers in the UK may have seen recent press reports about a controversial article by Bruce Charlton, an evolutionary psychologist at the University of Newcastle. Charlton points out that average IQ differs in different social or occupational classes (e.g. doctors or lawyers have higher IQ than casual labourers), and that in consequence, if IQ is relevant to higher education, we would expect participation in higher education also to vary according to class. Predictably, ritual curses and denunciations have rained down on Charlton's head.

I wanted to read Charlton's article, but found it more difficult to find than I expected. The press reports suggested that it appeared in Times Higher Education (the former Times Higher Educational Supplement), but on tracking down the relevant issue I found a report about Charlton's article, but not the article itself. The article is however available as a Word document on the THE website. (See the right margin of the webpage here). I make a few comments of my own below the fold.

Probably most readers will agree with the broad thrust of Charlton's article, but there may be a confusion between the IQ of parents and that of their offspring. Charlton seems (as far as I can see) to assume that the mean IQ of applicants to higher education is the same as that of adults in their parental social class. This is not generally the case. The correlation between the IQ of parents and offspring is only about .5, which implies considerable regression towards the mean. The IQ of the offspring of parents with IQ of, say, 130 will on average be lower than 130, while that of parents with IQ of, say, 85 will be higher than 85. There is a difference of up to 40 IQ points between adults in the highest and lowest occupational classes (depending on the classification used), but only about 15 to 20 points between children from those classes. (For some data see Anastasi, chapter 15.) The difference in average IQ between social classes is kept roughly constant by social mobility, as the dimmer children of the higher classes tend to fall in the social scale and the brighter children of the lower classes tend to rise. (See Mackintosh, pp. 144-8). This does not invalidate the main point of Charlton's article, but it may affect some of his specific quantitative comparisons.

I think it may also be unfortunate that Charlton describes the present system of entry to higher education as 'meritocratic'. Entry to publicly funded higher education should not be seen (primarily) as a reward for past achievement, or a badge of 'merit'. The proper criterion for entry decisions is how far an individual can benefit from the course of study concerned. In general, individuals who have struggled at school are unlikely to benefit from higher education at all. If applications for a particular course of study exceed the number of places available, those applicants should be chosen who will benefit most from the use of scarce resources. It is the scarcity of high quality resources that justifies the selectivity of the 'elite' universities. One would not expect an haute couture seamstress to stitch potato sacks, and one should not expect a Fellow of Trinity College Cambridge to teach mediocre students. Such students would not derive the greatest benefit from the teaching, and indeed the teaching would probably not be the best available for such students.

I am assuming in all this that higher education is by definition at a more advanced and demanding level than that of ordinary school education. It is not to be confused with post-school education at a similar level to that of schools, such as is provided by Further Education Colleges in Britain. This may be admirable in its own way, but it is not higher education.

Anne Anastasi: Differential Psychology, 3rd edn., 1958
N. J. Mackintosh: IQ and Human Intelligence, 1998

Labels: ,

Random!   posted by Razib @ 6/08/2008 01:33:00 AM

Check out this interview (radio) with the author. This is more about heuristics & biases than probability as such.

Saturday, June 07, 2008

On causes and religion   posted by Razib @ 6/07/2008 03:31:00 PM

Alan Jacobs of The American Scene has a piece in The Wall Street Journal titled Too Much Faith in Faith (also see Ross Douthat). He starts:
If there is one agreed-upon point in the current war of words about religion, it is that religion is a very powerful force. Perhaps you believe, with that vigorous atheist Christopher Hitchens, that "religion poisons everything"; or, with the Christian historian and sociologist Rodney Stark, that religion created modern science and ended slavery. Or, like a significant majority of the British public recently polled by the Joseph Rowntree Foundation, that religion is a "social evil," a "cause of conflict and confusion." But in any case you're likely to think that, for good or ill, the sheer impact of religion is enormous.

Is it, though?....

As they say, read the whole thing. Alan, as a Christian, place particular focus on the New Atheists who wish to leave at religion's feet all evil done it in its name but explain away as incidental all the good whose motivation was putatively supernatural. But he does note there are those such as Rodney Stark, an extremely pro-Christian sociologist, who would ascribe to religion all the good in the world while staying relatively silent on the evil enacted in the name of God (or, the usual special pleading that "that's not the real fill-in-the-blank-religion"). Below are a few general responses I have to Alan's piece.

1) Religion means different things at different times and different contexts, and it means a lot. That's a mouthful, but what I mean by this is that there is a lot of debate on what exactly religion entails on the margins. There are particular core traits which people recognize as religious, but the fact that almost every random functionally unrecognizable material remain has been classified as a "religious cult object" by archaeologists illustrates the catchall nature of religion. Additionally, different religions have different emphases; some are more focused on "orthopraxy," and some are more fixated on "orthodoxy."

The distinction is important in Christian cultures because I think it can be argued that Christian religiosity in the modern West, especially the Protestant West, is highly focused on doxy, belief, as opposed to praxy, practice. In most other major world religions one may make a point that praxy is much more emphasized on a relative scale. This contrast lay at the heart of the book The Impossibility of Religious Freedom, where the author makes the case that American legal structures are designed to accommodate Protestantesque religions (I think one can make the case that Reform Judaism is Protestantized, and one can also argue that American Catholicism has a fundamentally Protestant character in terms of how believers relate to their church despite what Church teaching might be). These structures are not well prepared to deal with the different needs of orthopraxic traditions. This is not to say that all major religions do not have both dimensions, but I think it is clear that profession of a precise belief plays an outsized role in terms of identity for an evangelical Christian in comparison to those who consider themselves Hindus or Jews.

Multi-dimensionality is also important, religion as a phenomenon bleeds into many aspects of life and draws from a multitude of human propensities. One major failing, in my opinion, of militant atheism is its tendency to overestimate the religiousness of any particular act which is claimed to be religious. I've made this sort of argument most explicitly about Christmas; for some people the season has obvious religious intent and meaning, but it is clear that the main features of Christmas as a cultural festival were co-opted from pre-Christian and non-Christian practices. The Christmas tree, yule log and ginger cookie making all have explicit pre-Christian antecedents and pagan religious significance (the latter is clear when you note that the Christian Church often banned many of these practices). This does not mean that these practices are anti-Christian, or even that they can not be given Christian significance (e.g., the Star of Bethlehem at the top of many Christmas trees), but rather that the religiosity, or lack thereof, of any particular practice is a very complicated issue to ascertain.

If you evaluated a sample space of human characteristics, and then tabulated the number of those characteristics which contribute in some manner to religiosity or the religious phenomenon I would daresay one might note that a substantial subset of the former are contained in the latter. The intersection is most clear in what some scholars might term a political religion, mass social movements often spearheaded by a charismatic figure which posit an eschatology. Obviously political religion intersects substantially with supernatural religion in terms of its parameters. In fact, on many occasions political religion starts to mimic supernatural religion; e.g., the bizarre legends which Kim Jong-Il's regime in North Korea promotes about the miracles attendant upon the day of his birth, such as flowers blooming in winter! The power of political religion is clear to us today in the modern world, but we can see that it lacks the temporal robusticity that supernatural religion has. The god of political religion is a material figure who dies, and the only way to maintain the charisma around his person is to engage in apotheosis and supernaturalize him (note the peculiar preservation of the body of Lenin). Supernatural religions on the other hand persevere beyond the death of their founders and can connect the generations of the past to those of the future through the mediating power of supernatural agents, whose concrete existence is irrelevant to their affect on human cognitive states.

What does this have to do with Alan's post? Obviously men such as Richard Dawkins are opposed to the evils of religion, but they are often accused of not paying proper attention to atheistic Communism and Nazism. Let's sidestep the fact that Nazism had at least a Deistic core, Communism was avowedly an atheist ideology. The New Atheists might claim that the evil of Communism was not committed in the name of, or because of, atheism, but rather due to collectivist and totalitarian political ideology. But, I would hold that these are exactly the aspects of religion which the New Atheists use as a cudgel against religion! If you read Dawkins' The God Delusion he obviously has contempt for the hypothesis of God itself as infantile, but his most trenchant critiques hinge upon the material consequences of religion, the irrationality of behavior and policy (from his perspective) which are rooted in religious ideology. But the homophobia, patriarchy and Puritanism which were extant in the former Communist countries strongly suggests that social characteristics which secular liberal elites decry because of their associations with religion will not be mysteriously banished with the death of the gods. It is to me somewhat ironic that the New Atheists often invert the concepts of religionists, whereas the latter might posit a utopia under the aegis of their god the former seem to project a godless future where the dark hand of the divine has been removed and so the lion may now lay with the lamb! It seems they forgot to remember that His Dark Materials was fiction.

2) The previous point attempted to emphasize that because religion is so broad, and so interconnected with various other aspects of human sociality, it is very difficult to adduce that religion as such is the causal factor underlying a particular dynamic. I think that the missteps by scholars such as Max Weber in overemphasizing the importance of religious ideas in driving the nature of a society or culture illustrate this. Weber famously suggested that a Calvinist ethic drive the rise of modern capitalism, using Germany as an example. Though there are debates as to the validity of Weber's assertions (the majority seem to believe the idea falsified, though there is a revisionist minority), his assumption that East Asian societies would never modernize economically because of their Confucian/Buddhist religious sensibilities shows the weakness of this sort of black-box approach to religion.

One point which Alan suggests is that those who accept the claims of religionists in terms of their rationale for a given behavior needs to be treated with skepticism. Humans are incredibly fluent fabulists, and not only can we lie to others with relative ease, that ease comes more easily when we lie to ourselves. This is a general observation; in extreme cases one would assume that those who destroy the lives of others in their own self-interest engage in self-deception as to assuage their own guilt. Obviously a woman who kills her own child because she believes that he is Satan incarnate is insane and delusional, that's not the sort of normal cognition which I'm talking about. Rather, humans have a tendency to attribute cause to the random, virtuous ultimate intent behind short term gratification via vice. Consider the psychology of a serial killer such as Jeffery Dahmer who converted to Christianity before his death. Dahmer may sincerely have believed his conversion was due to his personal experience with God, but I assume many would wonder if part of his mind was very intent on absolving himself of his sins, and that the Christian God was the avenue toward such absolution. These dynamics are not limited to religion, consider a man who cheats on his wife because such behavior is "natural," or a capitalist who exploits his employees and cheats his consumers justifying it somehow via the natural workings of a free market. Human psychology is complex, and our decision making process is not driven by a unitary rational agent. Most importantly, we do not have easy access to our own subconscious mental processes which shape the course of our decisions, though we freely manufacture explanations which give us a sense of the reasoning behind our decisions.

3) In point #1 I tried to suggested that religion is such an expansive phenomenon, intercalated with other social processes, that we need to be very careful in ascribing any particular good or evil to religion as such. In point #2 I try to point out that the psychology of religion is also rather complex, and how people relate to their religion, and the explanations they offer about how they relate, should be taken with a grain of salt. These are generally negative points, expressions of skepticism and agnosticism about the assertions which religionists and anti-religionists regularly make. In The End of Faith: Religion, Terror, and the Future of Reason Sam Harris naively explores the irrationality of religion by taking at face value the assertions of religionists. To me this is like making inferences about mantle geophysics by examining what you see from satellite photographs in terms of surface topography.

But this negation of positive assertions does not mean that one can not make generalizations about religion. Muslims tend not to drink alcohol, Jews tend not to eat pork, and Christians tend not make distinctions of kind among believers. These are generalizations which capture particular trends. Jews who adhere to halakah and Muslims who follow sharia, or Hindus who follow prescribed customs & traditions deviate from expectation unless you know their religious identity. But does this make a difference in the shape of the world around us? To some extent, yes. On the other hand, how much does it matter?

I approach issues from the perspective of an atheist. I don't think there are transcendent supernatural truths in the universe, or, more precisely I don't know what terms like "transcendent supernatural truths" are supposed to mean, nor do I feel that the claims made by any religion I've encountered are coherent. For most religionists this is not true, claims of a supernatural grounding to the universe are plausible to them. I suspect this is in large part a function of human propensity toward detecting and assuming agency in the universe around us. The world has purpose, and behind purpose must be agency, and an intelligent agent. The baroque theologies and institutional scaffolding which we attribute to religion are built upon this foundation, and no matter the cathedral that you construct with your mortar the necessary precondition and ultimate constraint are resident within the essence of your building material.

Therefore, I believe laws that are presumed to emanate from God on High have more power and hold on human psychology than laws which are derived from man. But the reality is also that by and large gods don't walk amongst us, and believers must rely upon priesthoods or personal judgement to interpret the will of God. And this is a critical point: the power of divine law lay in its origins on the ultimate Ground of Being, but how we implement the law is highly contingent upon personal circumstance. For me the clearest example was of a Muslim ruler in Africa who had enslaved all non-Muslims within his domains and so perceived a deficit of revenue. His solution was simple, he imposed a very high tax upon his Muslim subjects, and when they were not able to pay the tax he obtained from a religious scholar a ruling that those who disobey their ruler are apostates and non-Muslims, and since his subjects could no longer pay their tax they were now available for enslavement. This is an extreme case, but I mention it to show the ingenuity of human interpretation. Islamic banking is a more prosaic illustration of how one can satisfy the letter of the law to one's own sincere satisfaction and yet remain transparently self-interested to outside observers.

This is not to deny that a particular religious dispensation might ensure and encourage particular changes, but the rationales for those changes, and their permanence, should be questioned. For example, in parts of Southeast Asia some individuals in pagan communities have converted to Islam or Christianity and praised the frugality which their new religion enabled. The explanation is that particular feasts which the village would throw to placate ancestors and tribal gods were a severe economic burden, and those who converted to a world religion would obviously have opted out of the collections for these pagan events. Over time these communities will almost certainly become uniformly Christian or Muslim. At that point does one suppose that the economic expenditures of the community would be reduced permanently because of the lack of servicing of tribal gods and ancestors? I doubt it, rather, the extant evidence from Christian and Muslim communities suggests that these religious traditions have festivals and institutions which require funds from all believers who are capable of paying (i.e., those who are not destitute). Early converts of course would receive a windfall benefit during the transition between the old and new religion, because they would have opted out of the institutional system of the old before that of the new had arisen. I use the above example to show how one must focus on dynamics and epiphenomenal details when examining social and historical questions. The early Protestants accused the Roman Catholic church of being debased and pagan, and looked back to the primitive Christians as their exemplars, but I suspect that the nature of the Roman Catholic church resembled Roman state paganism because universal religions which depend upon state patronage develop particular characteristics. Additionally, sectarian dissenters as a self-selected minority have their own peculiar characteristics which might make some critiques inevitable byproducts of the structural relations of the social and political system.

4) Though I do think it is likely that there are differences between the world religions on the margins in terms of how they habituate their believers, I think we need to be cautious of generalizations because there is often a sharp deviation between ideals and practice, and humans are given toward conflating their own circumstance with broad causes. It maybe that Islam is by its nature or historical development a more masculine religion than Christianity in terms of its appeal and methods, but I believe a more fruitful and easy to establish pattern is the general importance of religion in generating outgroup vs. ingroup dynamics. In other words, the sharp ritualistic differences between Rabbinical Jews and high caste Hindus in Kerala were less important in their judgement of each other than the fact that both adhered to strict rules in regards to ritual purity. To me the fundamental importance of obligate vegetarianism among many high caste Hindus is not the functional role this might play in terms of shifting nutritional intakes, but the fact that those on nutritional margins could not emulate this "costly signaller." It is notable that some low caste groups are scavengers upon meat because if they did not engage in these practices they might starve. The details of the hundreds of commandments which Orthodox Jews follow and the multitudinous interpretations of the implementation of these commandments is less important than the fact that the ritual lifestyle entails separation from those who do not adhere to said rituals. The details of the Nicene Creed are less important than the fact that some accept it, and some do not.

The ingroup-outgroup dynamics in world religions lead to the emergence of fictive kinship. Anthropologists and sociologists have done a great deal of work about the functional importance of religious groups for individuals in terms of generating social networks and undergirding civil society. Social networks and the emergence of civil society are not necessarily features of religion, but religion is sufficient to generate both, so its utility is rather clear. Japan is a society where religious belief and practice are far less salient features of mass culture than the United States, and yet it seems to have a robust civil society. So what's going on? Well, the Japanese are an extremely homogeneous people, their fictive kinship is based upon national identity. When New Atheists assert that the Japanese do not need religion to create a society which is characterized by low levels of social pathology as defined by little interpersonal violence they do not elucidate exactly the mechanisms and parameters which exist in the vacuum of powerful institutional religion.

I think that's about it for now. I think Alan's piece was a serious attempt to grapple with a lived reality which both the New Atheists and many religious thinkers don't seem to acknowledge. One would assume that if you were an empiricist that this would matter, but that doesn't sell books does it?


Friday, June 06, 2008

Review of Mongol   posted by Razib @ 6/06/2008 04:22:00 PM

In The New York Times of all places. Also, in Dana Stevens in Slate.

Google Pundit   posted by Razib @ 6/06/2008 11:13:00 AM

Ross Douthat points me to this Reason piece which eviscerates a "Google Pundit." I'm not too interested in the details of the article itself, rather, I like the term, and would add "Wikipedia Pundit" as another flavor of the same species. It's a problem everyone suffers from now and then, the urge to win the most pressing argument, but over the long term this sort of behavior doesn't add any value to one's own understanding of the issues at hand (and what else really matters?). This is of course not to denigrate the worth of Google or Wikipedia, but a monkey with a powerful computer is still a monkey. Especially in relation to social science questions it is almost trivially easy to find some "authority" who supports any given position.

Notes on Sewall Wright: Population Size   posted by DavidB @ 6/06/2008 05:30:00 AM

Continuing my series of notes on the work of Sewall Wright, I come to the question of population size. This is important in Wright's formulation of population genetics and his evolutionary theory generally. One of the major differences between Wright and R. A. Fisher is that Fisher believed that, in general, evolutionary processes could be treated as if they took place in a very large random-mating population. He did not believe, contrary to some caricatures, that species were literally random-mating across their entire range (which is obviously false), but rather that there was usually enough migration between different parts of that range that for most purposes the departures from random mating did not matter. Wright, on the other hand, believed that in many cases local populations were sufficiently isolated from each other that they could be treated as populations evolving separately. This difference of views had a major impact on Wright's and Fisher's assessment of the relative importance of selection and genetic drift.

In his treatment of genetic drift Wright showed that in the absence of mutation and migration, genetic diversity, as measured by the proportion of heterozygotes in the population, will decline at a rate of 1/2N per generation, where N is the relevant population size. The larger the size, the slower the loss of diversity. This raises the question what is the 'relevant' size of N. As Wright explained in his great 1931 paper 'Evolution in Mendelian Populations', 'The conception is that of two random samples of gametes, N sperms and N eggs, drawn from the total gametes produced by the generation in question (N/2 males and N/2 females each with a double representation from each series of allelomorphs). Obviously N applies only to the breeding population and not to the total number of individuals of all ages' (p.111, 'Evolution: Selected Papers' (ESP). Unless otherwise stated, all citations are from this source.)

Wright immediately goes on to say that this idealised model of the population is often an oversimplification. The effective size of the population is often different from the current actual number of breeding adults. If the effective size is smaller than the apparent size (the current number of breeding adults), genetic drift will be faster than expected. We may say that the effective size of the population is the size of an idealised population, meeting the criteria outlined in the quotation from p.111 given above, which would give rise to genetic drift at the same rate as actually observed. I am not sure that Wright ever formally defines effective size, but the definition I have suggested seems to be implied in various references, e.g. ESP pp.111, 157, 251, 354.

Wright repeatedly specifies three factors which tend to reduce the effective size of the population below its apparent size:

1) different numbers of breeding males and females (ESP, pp.112, 251, 299, 354, 370). The effective population size is closer to that of the rarer sex.

2) where variance in reproductive success greater than that assumed in the idealised model (ESP pp. 112, 251, 300, 354, 270), genetic drift will be faster.

3) Occasional or cyclical reductions in population size (ESP pp.112, 157, 251, 300, 354, 370). The effect of (non-selective) reductions in population size is to take a random sample out of the gene pool. Such samples will have a variance in gene frequencies proportional to 1/n, where n is the size of the sample. The smaller the number n, the larger the variance due to 'sampling error'. If n is small relative to N (the usual population size), the effect is equivalent to concentrating many generations of slow genetic drift into a single event. In the absence of mutation and selection the effect is irreversible. A subsequent expansion of population, however large, does not reverse the loss of genetic diversity. (But note that if there is mutation and selection, an expansion of population gives an opportunity for rare advantageous mutations to appear and be selected. An expansion of population is also often associated with a relaxation of natural selection, which means that slightly disadvantageous mutations, which would normally be weeded out, may survive. This could help shift the population across a 'valley' in the adaptive landscape, if such things exist).

These three factors all tend to reduce the effective population size below the current observed number of adult males and females. Wright repeatedly claims that the effective size is usually less than the apparent size, for example, 'The effective size (N) of the theory may, however, differ much from the apparent size, being usually much less' (ESP p.251). So far as I know, Wright only once mentions a factor that might increase the effective number above the apparent level: on ESP p.300 he mentions that the variance in reproductive success could be less than in the idealised model, in which case the effective population number could be up to twice the apparent size. But he comments that this improbable except in planned breeding experiments.

So far so good. But so far as I am aware, Wright never mentions another factor which may raise the effective population size above the current number of breeding adults. This is where there is a large reserve of juvenile or dormant individuals with the ability to replace the current adults in the event of a population reduction. Such a reserve population would contain a greater amount of genetic diversity than the reduced number of current adults. This is probably a minor factor in the case of vertebrate animals, but could be important among some small invertebrates, where the number of eggs or larvae may be many times the current 'crop' of adults. It is even more important in the case of plants. Most species of plants produce resistant seeds, bulbs, etc, which are orders of magnitude more numerous than the mature plants. In some cases they can survive for years or decades in a dormant state. The genetic effect of sharp reductions in adult population numbers (e.g. due to drought) may therefore be much less among plants than among animals. This oversight vitiated one of Wright's own major empirical studies (see Provine p.485).

Another major complication is migration. Wright's idealised model of genetic drift assumes that the population is completely self-contained, that is, reproductively isolated from other populations. If the population is an entire biological species, this is true by definition, since a biological species is defined by reproductive isolation. But if the population is a subdivision of a species, there is in principle the possibility that genes will enter the population from outside. My next note will examine how Wright dealt with this complication.

William B. Provine: Sewall Wright and Evolutionary Biology, 1986.

Sewall Wright: Evolution: Selected Papers, edited and with Introductory Materials by William B. Provine, 1986.

Labels: ,

Thursday, June 05, 2008

1 - 0   posted by Razib @ 6/05/2008 08:59:00 PM

Oceania & population genetics   posted by Razib @ 6/05/2008 10:14:00 AM

Gene Flow and Natural Selection in Oceanic Human Populations, Inferred from Genome-wide SNP Typing (H/T Dienekes):
It is suggested that the major prehistoric human colonizations of Oceania occurred twice, namely, about 50,000 and 4,000 years ago. The first settlers are considered as ancestors of indigenous people in New Guinea and Australia. The second settlers are Austronesian-speaking people who dispersed by voyaging in the Pacific Ocean. In this study, we performed genome-wide SNP typing on an indigenous Melanesian (Papuan) population, Gidra, and a Polynesian population, Tongans, by using the Affymetrix 500K assay. The SNP data were analyzed together with the data of the HapMap samples provided by Affymetrix. In agreement with previous studies, our phylogenetic analysis indicated that indigenous Melanesians are genetically closer to Asians than to Africans and European Americans. Population structure analyses revealed that the Tongan population is genetically originated from Asians at 70% and indigenous Melanesians at 30%, which thus supports the so-called "Slow train" model. We also applied the SNP data to genome-wide scans for positive selection by examining haplotypic variation, and identified many candidates of locally selected genes. Providing a clue to understand human adaptation to environments, our approach based on evolutionary genetics must contribute to revealing unknown gene functions as well as functional differences between alleles. Conversely, this approach can also shed some light onto the invisible phenotypic differences between populations.

The stuff about candidates for selection:
Our scans suggested no private mutation to exist on the Tongan autosomes that had reached fixation. However, there remain alternative possibilities that old-standing alleles have reached fixation by local selective pressures and that newly generated advantageous mutations have gained a high frequency but have not yet reached fixation. The block showing the lowest RM value (0.076) in the test of TGN vs EAS using method 1 was located at 92788024-92838919 on chromosome 12...which is at 41 kb distance from the CRADD gene...It is worth noting that an approximately 500 kb deletion around this gene in mouse has been reported to cause a high growth mutant that shows a proportional increase in tissue and organ size without obesity...Another candidate for the selected region in which an old-standing allele reached fixation was VLDLR...which is involved in triglyceride and fatty acid metabolism...In addition, overlapping signatures in both methods 1 and 2...were observed in the gene region of EXT2, which is a causal gene of the type II form of multiple exostoses and it plays a crucial role in bone formation...These genes can be candidates that are associated with the large fat, muscle, and bone masses of Polynesians. A recent paper examining the interpopulation differentiation of the type II diabetes-associated genes has suggested that a susceptible allele of PPARGC1A may play a role in the large difference in the prevalence of the disease between Polynesians and neighboring populations...However, our scans did not identify any signiture of positive selection on the gene region of PPARGC1A.

One of the strongest signatures of selective sweeps in GDP was located at the region 22 including the LHX4 and ACBD6 genes on chromosome 1...LHX4 encodes a transcriptional regulator involved in the control of the development of the pituitary gland, and mutations in this gene are associated with syndromic short stature and pituitary defects...ACBD6 is a binding protein of acyl-Coenzyme A that has a role in fatty acid metabolism...The gene region of IGF1R, which is the receptor for insulin-like growth factor 1...was also considered to be a candidate of the selected genes...These genes may be involved in the slow growth, short stature, and light weight characteristics of New Guineans. Future association studies between genotypes and phenotypes are indispensable.

Other candidates of selective sweeps in Oceanic populations included several interesting genes such as DDX58, SIAT4A...and IVNS1ABP...which code molecules related with infection of the influenza A viruses...If we could identify a protective effect of the selected allele against the influenza, these kinds of signatures may therefore suggest evidence for the epidemic history of the virus in Oceania and human conquest of the disease by genetic adaptation.


Tuesday, June 03, 2008

Modeling human demographic history   posted by p-ter @ 6/03/2008 05:08:00 AM

In a previous post on current views on the human colonization of the world, I alluded two issues: whether modern humans displaced all archaics, and the precise demographic models under which that occurred. I placed more emphasis on the first, but was taken to task in the comments--apparently no one has issues with some version of the out-of-Africa story (ie. archaics contributed little genetic material to modern humans, if any), but there are some issues with the demographic models.

One paper pointed to is the Lohmueller et al. study on the high frequency of nonsynonymous polymorphisms in Europeans as compared to African-Americans. The authors do simulations under a variety of demographic scenarios, but rely heavily on a demography in which Europeans experienced a mild long-term bottleneck starting ~8000 generations (~160K years) ago, while the African populations instead experienced population growth. For those keeping track at home, humans aren't estimated to have left Africa until about 2000-4000 generations (40-80K years) ago. So these models rely on two populations having different demographies during a period of time before they split, an impressive feat indeed. So alright, some demographic histories aren't exactly the most believable.

That said, all bottlenecks are not created equal. The fact remains that as you move away from Africa, each population contains a subset of the diversity of the ones the precede it--this is indicative of each population being founded by a subset of those preceding individuals. And allele frequency spectra, when measured in different populations (see the figure here), are inconsistent with constant population size in Europe and East Asia, and imply instead a bottlenck, stronger in E. Asia than in Europe, in recent demographic history. Any reasonable model has to take these observations into account.


Monday, June 02, 2008

The Paskowitz Family and the unwritten moral law   posted by Razib @ 6/02/2008 10:58:00 PM

Reihan has a post up, The Paskwotiz Family, where he praises the new documentary Surfwise. I first heard about this family a few weeks ago on the radio show On Point; the director of the documentary and a few of the sons were interviewed at length. Reihan finishes:
I get the point. I sympathize! But note that there’s no getting out of the "iron cage." Mind you, I'm pro-modernity, pro-market. What troubles me (us?) about the Paskowitz story, which of course I invest with a lot of romance and affection, are the constraints on the kids - what was their context of choice, and how could they live full lives in a market society?

Reihan is alluding here to the fact that though Dr. Dorian Paskowitz has a medical degree from Stanford he doesn't send his children (seven of them) to schools in keeping with his counterculture orientation. A month ago I posted When the weirdos are white, in reference to the state of Texas' forcible intervention in the family lives of Fundamentalist Mormons. The intervention was clearly due to moral unease with the nature of the lives these Mormons led and the expectations that we Americans have in terms of our fellow citizens. As white Americans of no peculiar ethnic identity Fundamentalist Mormons were not shielded by the tendency of elite moderns to cut a bit of slack to the Other (the Amish are a more extreme case in their difference from society so more slack is given).

The reactions of the Fundamentalist Mormons and the Paskowitz family I think smoke out the contradiction at the heart of contemporary elite Western life: the simultaneous superposition of a disavowal of judgement & absolute values and an adherence to a set of standards which scaffold and guide one's life rather rigorously (e.g., the "best schools," the "fulfilling careers" and the "loving spouse"). Conservative Christians in the United States often see themselves as in contradiction to the values encapsulated by the dominant dispensation, and so I believe though they are often guilty of myopia they can easily elucidate the general outline of what they mean by the Good Life. In contrast, mainstream America, the pulse of which is defined by upper middle class professionals, the English gentry of our day, often adhere to a set of values implicitly and discernible only through the subtext of their words and actions.

Societies have norms. When individuals and groups violate those norms society sanctions them in some manner because of their revulsion at the violation of those norms. But many modern Americans have a tendency to mask the causal factor behind this revulsion, the transgression against particular taboos or beliefs & folkways held sacred, and talk as if in reality it was some more abstract and distant ultimate principle which motivated them. For example, the extraction from children from "dangerous" parents is to allow the children to "make up their own mind" and not be "brainwashed," because after all humans with free choice and will always make the "right" choices. So you simply turn it into a general issue of individual choice as opposed to a specific reaction to an infraction against the unwritten moral law. A more more explicit exploration and discussion of the values which "mainstream" Americans hold might be in order for our society I would think. But then, I value transparency....


Chance in evolution   posted by p-ter @ 6/02/2008 09:22:00 PM

Carl Zimmer tells a fascinating story about the role of chance in E. coli evolution. The paper isn't available yet, of course, since it's PNAS, but it certainly sounds like it's worth a look.

Update from Razib: Also see Ed Yong's post.


Henry Louis Gates Jr. interviews James Watson   posted by Razib @ 6/02/2008 10:13:00 AM

If you have't stumbled on it.

Selection speculation: CLOCK and reward-dependence in Africans   posted by agnostic @ 6/02/2008 02:39:00 AM

Since so many comments lead off with some variant of "I would guess," why not try to corrall them all into one post where they could serve a purpose? Each week I'll find some area of the human genome that shows signs of recent selection, see what phenotypes the gene affects, and although I'll likely provide the most convincing story, readers can conjecture to their heart's content about what might have driven selection. It may, for once, improve the discussion to comment while still deranged from last night's drink.

Let's start with the data: using Haplotter, we see that for the gene CLOCK, there is a signal of recent selection in Africans but not in Europeans or Asians. The CLOCK gene is involved in maintaining our circadian rhythm, and I started this search looking for between-group differences in being "day people" vs. "night people." However, other genes related to circadian rhythm -- PER1, PER2, PER3, Tim, CSNK1E, Cry1, and Cry2 -- show no signals of recent selection anywhere. So perhaps there is something else that CLOCK does that these others do not.

It turns out that CLOCK is also involved in the dopaminergic system, which regulates mood and behavior. None of the OMIM entries for the other circadian rhythm genes mentions dopamine, mood, the reward system, etc. So it is more likely that CLOCK has undergone selection for its effects on mood and on the brain's reward system, rather than on circadian rhythm per se. In mice, and so potentially in humans as well, mutations in CLOCK make individuals lower in anxiety and higher in risk-taking (Roybal et al. 2007; free full text).

Turning to data from Lynn & Martin (1995), which I turned into a convenient graph here, we see that Nigerians -- the African group that HapMap data come from -- are indeed the lowest in the world in the personality trait Neuroticism (the Israeli data-point must be a mis-coding by Lynn, who is known for doing so). They are also the highest in the world in Extraversion. Neuroticism measures a tendency toward anxiety and related states, while Extraversion measures, among other things, pace of living (manics living a faster-paced life) and excitement-seeking. So Nigerians show a psychological and behavioral phenotype that's fairly comparable to the mice with mutations in CLOCK, strengthening the hypothesis that selection at CLOCK has acted on personality rather than circadian rhythm per se.

Now comes the fun part -- telling a story about why this phenotype was more advantageous in Western Africa than in Central Europe or Northeast Asia over the past 10,000 or so years. The low-anxiety and high-excitement-seeking phenotype is suspiciously like that associated with derived alleles at the DRD4 locus, and the novelty-seeking 7R allele at that locus does show up at intermediate frequencies in Africans (Chen et al. 1999; see a map here). I concur with Harpending & Cochran (2002) (free full text), who argued in the DRD4 case that the phenotype is more advantageous in "cad societies" than in "dad societies."

More concretely, I suggest, based on the teachings of the pickup artist community, that low anxiety aids in approaching more females in a shorter time -- you are less paralyzed during the approach, and you get over rejection more easily -- and that higher risk-taking motivates you to approach more females. Contingent upon having other traits that are appealing to females (a muscular body, artistic skill, dancing or singing ability, a knack for flirting, and so on), the phenotype here would have increased male success in courtship of (multiple) females, a stronger determinant of reproductive success in a "cad society" than in a "dad society."

Lastly, here are two testable predictions: 1) lowland South American and highland New Guinean tribes should also show signs of selection at the CLOCK locus, since they are even more prototypically "cad societies," and they have the highest frequencies of the 7R allele at DRD4. And 2) African Bushmen should show no signs of selection at CLOCK since they are more "dad societies" and have lower frequencies of the 7R allele at DRD4. (ALFRED does not have data on CLOCK.)

The fact that Northeast Asians do not show signs of selection at CLOCK already supports the hypothesis, since they are more "dad societies" and have a very low frequency of 7R at DRD4 (and even the 2R allele, which shows up somewhat there, has a much more muted effect than does 7R). The lack of selection at CLOCK in Central Europeans is neither here nor there: they are more "dad societies" than Western Africa but not so much as East Asia; Europeans also have intermediate frequencies of 7R and DRD4. So we could have an example of "Rushton's Rule," where East Asians show no selection for low-anxiety / high-novelty-seeking alleles at either DRD4 or CLOCK, Europeans show selection at just one locus, and West Africans show selection at both.

To the best of my knowledge, as they say, this is the first argument for why Africans show a signal of selection at CLOCK. Consider it part of the graduate student with a PC trend in studying human evolution. You heard it here first.


Chen, C., M. Burton, E. Greenberger, & J. Dmitrieva (1999). Population migration and the variation of Dopamine D4 receptor (DRD4) allele frequencies around the globe. Evolution and Human Behavior, 20(5): 309-324.

Harpending, H. & G. Cochran (2002). In our genes. PNAS, 99(1): 10-12.

Lynn, R., & T. Martin (1995). National differences for thirty-seven nations in extraversion, neuroticism, psychoticism and economic, demographic and other correlates. Personality and Individual Differences, 19(3): 403-406.

Roybal, K., D. Theobold, A. Graham, J.A. DiNieri, S.J. Russo, V. Krishnan, S. Chakravarty, J. Peevey, N. Oehrlein, S. Birnbaum, M.H. Vitaterna, P. Orsulak, J.S. Takahashi, E.J. Nestler, W.A. Carlezon, Jr., & C.A. McClung (2007). Mania-like behavior induced by disruption of CLOCK. PNAS, 104(15): 6406-11.

Labels: , , , , , ,