A Replicated Typo empire
Just want to note that GNXP contributor bayes has transformed A Replicated Typo into a fascinating group weblog. Feed here.
Cultural Diversity, Economic Development and Societal Instability
Most of you in the science blogosphere have probably come across Razib’s recent post on linguistic diversity and poverty. The basic argument being that linguistic homogeneity is good for economic development and general prosperity. I was quite happy to let the debate unfold and limit my stance on the subject to the following few sentences I posted previously:
From the perspective of a linguist, however, I do like the idea of really obscure linguistic communities, ready and waiting to be discovered and documented. On the flip side, it is selfish of me to want these small communities to remain in a bubble, free from the very same benefits I enjoy in belonging to a modern, post-industrialised society. Our goal, then, should probably be more focused on documenting, as opposed to saving, these languages.
Since then, the debate has become a lot more heated, with Neuroanthropology wading in against Razib, which, in the second-half of the post at least, is worth reading just to get the general flavour of the other side in this debate. Having said that, I wasn’t convinced by the evidence Greg Downey used to dismiss Razib’s hypothesis, so I decided to actually look at the literature on the subject. The first paper I found upon searching was one by Nettle et al, in which they examine the relationship between cultural diversity and societal instability using a large cross-national data set of 212 nations. Importantly, they look at cultural diversity in the context of three areas: linguistically, ethnically and religious affiliation. Also, they draw a distinction between within-nation (alpha) diversity and between-nation (beta) diversity. Lastly, unlike other studies on the subject, where simple regression or correlation methods are used, the current study employs structural equation modelling (SEM):
The Price of Altruism
A week ago I reviewed The Price of Altruism: George Price and the Search for the Origins of Kindness. As I noted in the review, many individuals who are of interest to the core readership of this weblog make significant appearances in The Price of Altruism, John Maynard Smith and W. D. Hamilton most prominently. Since I wrote that review I will divulge the fact that I met the author, Oren Harman, and George Price’s daughters. Oren confirmed to me a supposition I arrived at via reading The Price of Altruism, that George Price was already a zealous Christian when he was working on his core contributions to the evolution of social theory and altruism. In particular, the “hawk” and “dove” morph terms which John Maynard Smith utilized in his work on evolutionary game theory, and Richard Dawkins popularized in The Selfish Gene, were suggested by Price during his Christian phase. Later he suggested that Smith change the term “dove” lest people assume that his Christianity had unduly influenced Price’s choice of terms. I found it ironic that the bulldog of the New Atheism, who has emphasized the necessary connection between being an evolutionist and an atheist, has been one of the most prominent of expositors of ideas which derive in large part from a fundamentalist Christian evolutionist! (for details of Price’s Christianity, and why it could be termed fundamentalist, see The Price of Altruism).
I will also add that after meeting Price’s daughters, and listening to their recollections of their father, I suspect many readers of this weblog would recognize in George Price a kindred spirit. Harman speculates that today Price might be somewhere along the autism spectrum deviated from the population median toward Asperger’s. Additionally, his intellectual interests were far wider than I had understood. Prior to his work on evolution Price had corresponded with Paul Samuelson on the possibility of reworking the foundations of neoclassical economics, and, also had developed a close relationship with B. F. Skinner (though this soured as Price rejected Skinner’s Behaviorism, and as was usual with him was not particularly politic in the manner of his rejection). It seems likely that George Price lacked some things in his personality portfolio, but the absence of those things drove him precisely into the “startling landscapes” which W. D. Hamilton referred to when alluding to the originality and power of the Price Equation.
So I guess with that, I’m saying I highly recommend the The Price of Altruism to readers of this weblog, both for intellectual and biographical reasons.
Social and individual behavior genetics
I believe it was Bryan Caplan who introduced me to the analogy of a child’s personality being like a rubber band; parents, in particular adoptive parents, can twist and pull a child in particular directions so long as the child is under their direction, but once the child leaves the home the rubber band “snaps back.” This is basically communicating the fact that heritabilities on many psychological traits increase as people age. Concretely, adopted children resemble their biological parents more and more in their outcomes and dispositions as they mature. This can probably be explained in part by gene-environment correlations and positive feedback loops. I wouldn’t be surprised if this is most evident in WEIRD populations which are the targets of behavior genetics studies, because of the importance of individual choice and self-actualization once one reaches adulthood in WEIRD societies. If you are Amish or a Fundamentalist Mormon it may be that there isn’t enough environmental variation for gene-environment correlation to ever become particularly powerful.
Which brings me to cross-cultural analogs to patterns of individual variation. In response to this article in The New York Times, One Bride for 2 Brothers: A Custom Fades in India, Steve says:
This is a good example for my overall view of human nature. Rather than there being absolute universals (never say never), at least among the kind of thing people find interesting to argue about (nobody is interested in the fact that air-breathing is a human universal), there are tendencies. Polyandry goes strongly against human tendencies, but under some conditions can exist as a cultural norm. But, as people get more money, they rebel against the culture of polyandry.
This was my basic thought as well. But one thing I would add in the context of India: the rise of mass media and a common national elite culture has resulted in a great deal of homogenization in regards to particular values over the past 150 years. For example, many Indian groups have shifted from brideprice to dowry systems over the past 100 years as part of a process of “Sanskritization.” In Kerala high status Nairs abandoned the Sambadam practice in part due to to the fact that it seemed deviant and immoral to other Indian elite groups. It is also relatively well know that many Indian Muslims who were not of the Turco-Persian (at least in part) elite tended to have relatively syncretistic practices until recently, but Islamic “reform” movements have progressively aligned Indian non-elite Muslims with elite practices and identity (the founder of Pakistan was arguably from a syncetristic background, a possibility which is obviously not emphasized in modern Paksitan). But something similar has also occurred with groups which identify as Hindu, even if it is not as explicit because of Hinduism’s more decentralized nature. In other words the natural predispositions of humans, in particular males, to avoid polyandrous relationships when possible has probably been amplified by cultural norms which have spread and encouraged conformity to the preferred ideal.
The Media Noose: Copycat Suicides and Social Learning
I always remember 2008 as the year when the entire UK media descended upon the former mining town of Bridgend. The reason: over the course of two years, 24 young people, most of whom were between the ages of 13 and 17, decided to commit suicide. At the time I was working in Bridgend, so I’m able to appreciate the claims of local MP, Madeleine Moon, that media influence had become part of problem. After all, most editors will tell you: the aim is to sell newspapers. And when this rule is rigorously applied, it should not come as a surprise at the depths some journalists will sink to recycle a news story. Even at a local-level, where you’d think some civic responsibility might exist, journalists clambered over themselves to find a new angle, generating ridiculous claims such as: electromagnetic waves from mobile phones caused the suicides.
Genomes Unzipped
If you haven’t, checked out the new weblog Genomes Unzipped. Familiar names & faces. The first posts are already must-reads, Testing for traces of Neanderthal in your own genome, and Personal genomics: the importance of sequencing.
The inevitable intelligence
I think about Luke Jostin’s analysis of the growth in cranial capacity in the hominin lineage from last spring a fair amount. In particular, in the comments he notes:
The data above includes all known Homo skulls, but none of the results change if you exclude the 24 Neandertals. In fact, you see the same results if you exclude Sapiens but keep Neandertals; the trends are pan-Homo, and aren’t confined to a specific lineage (though if you exclude Erectus everything goes skewiff, as you’d expect).
That brain size increases gradually in all lineages is another pretty strong argument against brain size being a macromutation.
I’ve put the species in the data file, if you want to play around with it yourself.
A particular configuration of traits or genes aligned early on in the existence of Homo seem to have resulted in increases in cranial capacities across divergent lineages. Robert J. Sawyer’s The Neanderthal Parallax series may be less fantastical in its premise than we would have thought.
Sexual orientation – wired that way
In a recent post, I presented the evidence that sexual preference is strongly influenced by genetic variation (http://www.gnxp.com/wp/uncategorized/sexual-orientation-–-in-the-genes). Here, I discuss the neurobiological evidence that shows that the brains of homosexual men and women are wired differently from those of their heterosexual counterparts.
First, we must consider the differences between the brains of heterosexual males and females. These differences are extensive and arise mainly due to the influence of testosterone during a critical period of early development (see Wired for Sex). They include, not surprisingly, differences in the number of neurons in specific regions of the brain involved in reproductive or sexual behaviours as well as differences in the number of nerve fibres connecting these areas. But they also involve areas not dedicated to these types of behaviours, such as the cerebellum, for example, which is involved in motor control among other things, and which shows a very large difference between men and women. Another area that shows prominent differences is the corpus callosum, the very large sheet of fibres that connects the two cerebral hemispheres, which is larger in females, despite lower overall brain size. Indeed, females show greater and more efficient connectivity in cortical networks than males, on average.
Birth Months of World Cup Players
Four years ago I (and others) got in a dispute with Stephen Dubner and Steven Levitt (DL) about their claim that birth month had a meaningful impact on later success in professional sports because kids born in January were “old” for their age group and were, therefore, more likely to make elite travel, national teams for U-17 tournaments and the like. These athletes benefited from the better coaching and competition that they faced relative to the kids who were born later in the same calendar year but with the same natural ability. DL predicted that
If you were to examine the birth certificates of every soccer player in next month’s [2006] World Cup tournament, you would most likely find a noteworthy quirk: elite soccer players are more likely to have been born in the earlier months of the year than in the later months.
Words as alleles: A null-model for language evolution?
For me, recent computational accounts of language evolution provide a compelling rationale that cultural, as opposed to biological, evolution is fundamental in understanding the design features of language. The basis for this rests on the simple notion of language being not only a conveyor of cultural information, but also a socially learned and culturally transmitted system: that is, an individual’s linguistic knowledge is the result of observing the linguistic behaviour of others. Here, this well-attested process of language acquisition, often termed Iterated Learning, emphasises the effects of differential learnability on competing linguistic variants. Sounds, words and grammatical structures are therefore seen to be the products of selection and directed mutation. As you can see from the use of terms such as selection and mutation it’s clear we can draw many parallels between the literature on language evolution and analogous processes in biology. Indeed, Darwin himself noted such similarities in the Descent of Man. However, one aspect evolutionary linguists don’t seem to borrow is that of a null model. Is it possible that the changes we see in languages over time are just the products of processes analogous to genetic drift?
Authenticity and the Fermi paradox
I know that the simplest explanation for the Fermi paradox is that we’re the first intelligent technological life form in the universe. But thinking about Paul Bloom’s thesis that a sense of “authenticity” is necessary for pleasure made me wonder a bit more about the possibility that once intelligent life forms get to the point where they can “re-wire” themselves they see no need to interface with the real universe. Instead they would retreat into their own virtual reality domains where they could create their own cosmos, and also successively re-program themselves in terms of their goals to such an extent that their probability of ever wanting to extract themselves from the imagined world is zero. In other words, any sufficiently advanced life form will lack curiosity about the authentic world as we understand it.
Can linguistic features reveal time depths as deep as 50,000 years ago?
Throughout much of our history language was transitory, existing only briefly within its speech community. The invention of writing systems heralded a way of recording some of its recent history, but for the most part linguists lack the stone tools archaeologists use to explore the early history of ancient technological industries. The question of how far back we can trace the history of languages is therefore an immensely important, and highly difficult, one to answer. However, it’s not impossible. Like biologists, who use highly conserved genes to probe the deepest branches on the tree of life, some linguists argue that highly stable linguistic features hold the promise of tracing ancestral relations between the world’s languages.
Previous attempts using cognates to infer the relatedness between languages are generally limited to predictions within the last 6000-10,000 years. In the present study, Greenhill et al (2010) decided to examine more stable linguistic features than the lexicon, arguing:
The two cycles
I’m reading Brotherhood of Kings: How International Relations Shaped the Ancient Near East. The book basically outlines the international state system in the ancient Near East which fostered diplomatic relationships between the monarchies of the period. It is noted that this state system and diplomatic culture did not make it through the chaos which marks the transition between what we term the Bronze Age and Iron Age; the centuries between 1200 and 600 BC. I try and read about the ancient Near East when I can, it’s a hard area to find academic books accessible to lay people (I don’t know Sumerian or Akkadian for example, which means that a lot of the philological stuff goes over my head). But thanks the usage of cuneiform tablets which are often well preserved when palaces are burned down we have a substantial amount of records, albeit not of the personable narrative form excluding some exceptions (good for economic historians, not so much for cultural historians).
Psychometrics, epigenetics and economics
Two papers of interest. IQ in the Production Function: Evidence from Immigrant Earnings (ungated). And Human Intelligence and Polymorphisms in the DNA Methyltransferase Genes Involved in Epigenetic Marking. My impression is that the focus on epigenetics has a higher-order social motive; even the sort of humanists who are involved with N + 1 have asked me about the topic. But how many people know what methylation is?
Is the “missing heritability” right under our noses?
One of the major criticisms leveled against genome-wide association studies for complex diseases is that they have identified loci which account for a relatively small proportion of the variance in most traits. The difference between this small proportion of variance explained by known loci and the (generally large) total amount of variance known to be due to genetic factors has been called the “missing heritability”. Much ink has been spilled speculating about where this missing heritability lies.
Two papers published this week suggest that maybe much of the heritability isn’t actually missing at all. The argument is simple: when performing a genome-wide association study, people use very stringent thresholds for calling a SNP associated with a trait. This is reasonable; people generally want to follow up only on true positives. However, there are probably many loci which don’t reach these highly stringent cutoffs but which truly influence the trait in question. Using methods to determine how much of the variance can be explained by these loci of smaller effect, one group suggests that about half of the heritability of height can be explained by common SNPs, and possibly close to all of it if other factors are taken into account. The authors have, in their discussion, one of the most reasonable, non-hyperbolic discussions of where the “missing heritability” lies, and how whole-genome sequencing will affect genome-wide association studies. It’s worth reading the whole thing, but here’s their conclusion::
If other complex traits in humans, including common diseases, have genetic architecture similar to that of height, then our results imply that larger GWASs will be needed to find individual SNPs that are significantly associated with these traits, because the variance typically explained by each SNP is so small. Even then, some of the genetic variance of a trait will be undetected because the genotyped SNPs are not in perfect LD with the causal variants. Deep resequencing studies are likely to uncover more polymorphisms, including causal variants that will be represented on future genotyping arrays. Our data provide strong evidence that the variation contributed by many of these causal variants is likely to be small and that very large sample sizes will be required to show that their individual effects are statistically significant. A similar conclusion was drawn recently for schizophrenia. In some cases the small variance will be due to a large effect for a rare allele, but this will still require a large sample size to reach significance. Genome-wide approaches like those used in our study can advance understanding of the nature of complex-trait variation and can be exploited for selection programs in agriculture and individual risk prediction in humans.
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Citations:
Park et al. (2010) Estimation of effect size distribution from genome-wide association studies and implications for future discoveries. Nature Genetics. doi:10.1038/ng.610.
Yang et al. (2010) Common SNPs explain a large proportion of the heritability for human height. Nature Genetics. doi:10.1038/ng.608.