Matt Yglesias has posted some charts showing that

1) Childlessness among women is becoming more common

2) The variation of this state by education is disappearing

Here’s the chart which illustrates the second phenomenon:

I think the reason this may be occurring is a dilution of the sample bias of women who have higher education in relation to the general ppoulation. In other words, as more women attain advanced degrees the pool of those women become less atypical vis-a-vis the general population

Read More

A few months ago I was thinking a fair amount about the Neandertals. One issue which became more stark to me due to that particular finding, that a few percent of the human genome seems to have derived from Neandertal populations, is the reality that genetic distinctiveness can persist long after cultural coherency is no longer a reality. That made me reconsider one of the facts of contemporary scholarship, that the Amerindian populations of the two most populous nations of the New World, the United States of America and Brazil, have disappeared or been totally marginalized demographically.

I’ve observed before it looks like that about 15-20% of the ancestry of the Argentine population is Amerindian, despite the nation’s proud identity as a European settler offshoot (i.e., more like the United States or Australia, than Mexico, which has an explicit hybrid identity). But I realized that Brazil was perhaps the bigger catch.

Only 0.4% of Brazilians identify as Amerindian. That’s about 700,000 people. But we know that a substantial number of white, brown and black Brazilians have Amerindian ancestry. Assuming for argument’s sake that the 700,000 Amerindians have undiluted indigenous ancestry, how much of the distinctive Amerindian genome in modern Brazil is to be found in this segment of the population?

There was a paper which came out in an obscure Brazilian journal last year which can help answer this question, DNA tests probe the genomic ancestry of Brazilians. For the purposes of the paper they needed to find a small number of ancestrally informative markers which would allow them to partition the ancestries of the individuals in their data set into European, African, and Amerindian, segments. Luckily these are three very distinctive populations. They cross-checked the utility of their markers against the HGDP data set. In other words the precision and accuracy of the 40 markers they selected should be assessed by how well they can distinguish these three “pure” populations. Their Brazilian subjects consisted of self-identified whites from various regions, as well as black men from Sao Paulo. Brazil’s racial taxonomy has a brown (pardo) category which is large, but judging from the very high proportion of African ancestry among the blacks in their sample I don’t think they included self-identified mixed-race people in that group (some scholars lump mixed and black Brazilians together into the black category).

Read More

There will be an interesting presentation tomorrow at the European Society of Human Reproduction & Embryology. Basically the researcher is going to present on a method for predicting when a woman will hit menopause. This part from the press release is the important bit:

“The results from our study could enable us to make a more realistic assessment of women’s reproductive status many years before they reach menopause. For example, if a 20-year-old woman has a concentration of serum AMH of 2.8 ng/ml [nanograms per millilitre], we estimate that she will become menopausal between 35-38 years old. To the best of our knowledge this is the first prediction of age at menopause that has resulted from a population-based cohort study. We believe that our estimates of ages at menopause based on AMH levels are of sufficient validity to guide medical practitioners in their day-to-day practice, so that they can help women with their family planning.”

The method:

Read More

I highly recommend this discussion between Paul Bloom & Robert Wright. The topic under consideration is the psychology of pleasure, as reviewed in Bloom’s new book How Pleasure Works: The New Science of Why We Like What We Like. You can also find out about Bloom’s ideas in this exchange in Slate. The essentialism examined in Descarte’s Baby is being taken for another spin, though with a more precise focus. The bottom line is that pleasure is often contingent on more than proximate empirical sensory input; it depends on what you perceive to be the essence of the object of pleasure, even its history (or more crassly, its price). This truth may make the calculation project of the utilitarian heirs of Gottfried Leibniz pragmatically impossible.

Read More

Dave Weigel of The Washington Post has resigned over his juvenile postings on an e-list. Basically the postings allowed for Weigel’s mask to slip, and showed him to be a vulgar and immature young man in some contexts. That’s no different from many of us in the proper context. The e-list is now defunct because of this information break.

Someone like Dave Weigel, a reporter who has to make a public pretense toward objectivity, and a somewhat public person, is atypical. But I think it’s the tip of the iceberg. People who know me in “real life” know that nothing they say to me will ever show up on this blog; it’s private, and my day to day interactions almost never intersect with the topicality here. If I want to introduce an idea or concept that someone else familiarized me with I will ask if I can do so, and credit them if they request. But that’s the nature of this blog, which draws more upon the scientific literature or reader feedback. Other outlets blur the line between private & public more explicitly, and if you meet someone with such an outlet, watch what you say, watch what you do. I’ve been on private e-lists where people say things that in public that could really compromise them. I’ve even gotten into disputes with people who were taking one stand in public which I knew could be easily undercut if I “exposed” what they’d said in private.

In the short term by breaking down barriers to information flow the internet is going to result in people retrenching to the narrowest and most trusted circles to “let their hair down.” In the long term I think we might have to reconceptualize what we think of as private or public. Soon enough a whole host of data on anyone you meet will be available on demand. And your data will also be available to them.

Read More

23andMe research article finally published. Dr. Dan MacArthur offers his take on a new PLoS Genetics paper which was published using 23andMe’s user base. Of course there’s already information coming out of 23andMe’s user community not getting into the academic literature, see this comment below.

Group Solidarity and Survival. For what it’s worth, I think group solidarity was critical for human survival and flourishing. I suspect it was responsible for the secular increase in cranial capacity for most of hominin history.

Adverse drug reactions from psychotropic medicines in the paediatric population: analysis of reports to the Danish Medicines Agency over a decade. This looks like a correlation, so there might be the issue of the type of woman who is prescribed psychotropic medicines being more prone to have children with birth defects for other reasons. But something to think about.

Trust and Prosperity. This issue is not salient unless you move. There is a difference in trust even within the United States; rural Vermont vs. downtown Boston. The explanation for this difference is straightforward, but there are probably more subtle differences between societies. On an individual level I wonder at the aggregate decrement in productivity and energy due to having to “track” very vigilantly whenever you’re in a public place in a low-trust situation or society.

China’s Export Economy Begins Turning Inward. Remember that China’s population is about the same as the whole world in 1850.

There are very few books which would attempt to connect the experiences of the 1st century British who lived through Roman conquest with the French under the Vichy regime in World War II. The The Rule of Empires: Those Who Built Them, Those Who Endured Them, and Why They Always Fall by Timothy Parsons attempts to do just that. As John Emerson observed the subtitle is obnoxious; all states fall, not just empires. But in the author’s defense usually they are not the ones who decide upon the title, rather the publishers look for sentences which are catchy and can move some units. A grand explanation of why empires fall may appeal to the average reader. A disparate collection of descriptions of the imperial experience, filtered through a prism strongly shaped by 20th century perceptions and models of colonialism, perhaps not.  The latter is what the The Rule of Empires is. The author is a professor of 20th century African social history, and the specter of the European colonialism of the Dark Continent haunts even the chapters on Roman Britain or Umayyad Spain. Though Parsons’ sympathy with the subjugated is obvious he restrains himself enough so that tiresome polemic does not interfere excessively with the collation of fact or the attempt to engage in objective analysis. Unfortunately the project of a grand theory of the rise and fall of empires, or more accurately the colonized experience,  falls short of its goals. I was totally unpersuaded that the fall of Napoleonic Italy, Roman Britain, or British Kenya, were united in any deep way by inevitable social or institutional forces of history which thread together all empires. Though there are many interesting facts on display, it does seem to me that the author falls into a tendency to transform all imperialists into 20th century British, and all subjects into 20th century Kikuyu. The most recent imperial adventures serve as the models, or the skeleton, around which the grand theory is built, and that only distracts from the specific chapters which are rich with specific detail.

Read More

Larry Witham’s Marketplace of the Gods: How Economics Explains Religion is a manifestly ill-timed book. He states that “…around 2006 I began to notice a good deal of hoopla in the book market about economic explanations for just about everything-books that were best sellers.” Marketplace of the Gods was obviously written to capitalize on the prestige of economic explanations, but unfortunately it has come out after the bubble had burst on that market, so to speak. Within the past few years even many economists have come to admit that the power of their discipline’s logic can explain far less than they’d once thought. In fact, it seems a bit much for economics to explain everything when the core competency in financial domains are themselves being challenged. Even in 2008 in The Logic of Life Tim Harford was engaging in a rearguard attempt to prevent behavioral economists such as Dan Ariely from knocking the legs out from under the central thesis of his book. A more accurate subtitle for Marketplace of the Gods would have been “economic explanations of religion.” Not punchy or imperialistic, but true to the content of the text.

Read More

The Washington Post‘s blogger-journalist Dave Weigel has a post up where he preemptively apologizes for stuff he posted on an “off-the-record” e-list,. Extracts are going to be published by a gossip site. Journalists are the tip of the iceberg; privacy is fast becoming a total fiction, remember that. We’re slowly drifting toward David Brin’s model of a “transparent society”, but it’s happening so fluidly that people aren’t even noticing. And yet as I have noted before, people are resisting the push to merge all their personas into one. Interesting times.