The Idiocy of Categoric Purity

I realized yesterday that the Left has an odd idea of “purity” that underlies many of their otherwise inexplicable, reality-rejecting claims.

The left has, perhaps unconsciously, adopted the idea that if groups of things within a particular category exist, the groups must be totally independent and not overlap at all.

In the case of genetics, they think that for a genetic group to “exist” and be “real”, it must hail from a single, pure, founding population with no subsequent mixing with other groups. We see this in a recently headline from the BBC: Is this the last of the Aryans? 

Deep in India’s Ladakh region live the Aryans, perhaps the last generation of pure-blooded people and holders of possibly the only untampered gene pool left in the world.

These actually-called-Aryans might be fabulous, interesting people, but there is no way they are more pure and “untampered” than the rest of us. The entire sub-headline is nonsense, because all non-Africans (and some Africans) have Neanderthal DNA. They aren’t even pure Homo sapiens! Africans btw have their own archaic DNA from interbreeding with another, non-Neanderthal, human species. None of us, so far as I know, is a “pure” Homo sapiens.

Besides that, the proto-Indo-European people whom these Aryans are descended from where themselves a fusion of at least two peoples, European hunter-gatherers and a so far as I know untraced steppe-people from somewhere about Ukraine.

Further, even if the Aryans settled in their little villages 4,000 years ago and have had very little contact with the outside world over that time, it is highly unlikely that they have had none.

Meanwhile, out in the rest of the world, there are plenty of other highly isolated peoples: The Sentinelese of North Sentinel Island, for example, who will kill you if you try to set foot on their island. There was a pretty famous case just last year of someone earning himself a Darwin award by trying to convert the Sentinelese.

Now let’s look at that word “untampered.” What on earth does that mean? How do you tamper with a genome? Were the rest of us victims of evil alien experiments with CRSPR, tampering with our genomes?

The Chinese might figure out how to produce “tampered” genomes soon, but the rest of us, all of us in the entire world, have “untampered” genomes.

To be honest, I am slightly flabbergasted at this author’s notion that the rest of the people in the world are walking around with “tampered” genomes because our ancestors married some Anatolian farming people 4,000 years ago.

This strange idea pops up in liberal conversations about “race”, too. Take the recent AAPA Statement on Race and Racism:

Race does not provide an accurate representation of human biological variation. It was never accurate in the past, and it remains inaccurate when referencing contemporary human populations. Humans are not divided biologically into distinct continental types or racial genetic clusters.

But… no one said they did. At least, not since we stopped using Noah’s sons Shem, Ham, and Japheth going their separate ways after the Flood as our explanation for why races exist.

“See, human races are’t descended from Shem, Ham, and Japheth, therefore races don’t exist!”

Two groups of things need not be completely separate, non-overlapping to nonetheless exist. “Pillows” and “cloth” contain many overlapping traits, for example; there are no traits in “cloth” that do not also exist in “pillows.”

Colin Wight on Twitter articulates this beautifully as the “Univariate Fallacy”:

Click the cube. Watch it turn.

This fallacy, when deployed, is commonly done using a single sentence buried within an article or essay couched around a broader narrative on the history of a particular type of oppression, such as sexism. Let me give you some recent examples of this fallacy in action.

You’ll remember this @nature piece arguing that sex is a spectrum and that perhaps there are more then 2 sexes, even though over 99.98% of humans can be classified at birth as being unambiguously male or female. … [Link to piece]

In this piece, they hold off deploying the Univariate Fallacy until the second-to-last sentence of a nearly 3500 word essay.

So if the law requires that a person is male or female, should that sex be assigned by anatomy, hormones, cells or chromosomes, and what should be done if they clash? “My feeling is that since there is not one biological parameter that takes over every other parameter, at the end of the day, gender identity seems to be the most reasonable parameter.”

Please read the whole thread. It is very insightful.

For example, if you look at the so called “big five” personality traits, you find only 10% overlap between men and women. This is why it is usually pretty easy to tell if you are talking to a man or a woman. But if you you look at only one trait at a time, there’s a lot more overlap. So the trick is to take a thing with multiple facets–as most things in the real world are–and claim that because it overlaps in any of its facets with any other thing, that it does not exist. It is not pure.

Are our categories, in fact, random and arbitrary? Is there some reality beneath the categories we use to describe groups of people, like “male” and “female,” “young” and “old,” “black” and “white”? Could we just as easily have decided to use different categories, lumping humans by different criteria, like height or eye color or interest in Transformers, and found these equally valid? Should we refer to all short people as “the short race” and everyone who owns a fedora as “untouchables”?

Liberals believe that the categories came first, were decided for arbitrary or outright evil reasons, bear no relation to reality, and our belief in these categories then created them in the world because we enforced them. This is clearly articulated in the AAPA Statement on Race and Racism:

Instead, the Western concept of race must be understood as a classification system that emerged from, and in support of, European colonialism, oppression, and discrimination. It thus does not have its roots in biological reality, but in policies of discrimination. Because of that, over the last five centuries, race has become a social reality that structures societies and how we experience the world.

Race exists because evil Europeans made it, for their own evil benefit, out of the completely undifferentiated mass of humanity that existed before 1492.

This statement depends on the Univariate Fallacy discussed above–the claim that biological races don’t actually exist is 100% dependent on the UF–and a misunderstanding of the term “social construct,” a term which gets thrown around a lot despite no one understanding what it means.

I propose a different sequence of events, (with thanks to Steven Pinker in the Blank Slate for pointing it out): Reality exists, and in many cases, comes in lumps. Plants, for existence, have a lot in common with other plants. Animals have a lot in common with other animals. Humans create categories in order to talk about these lumps of things, and will keep using their categories so long as they are useful. If a category does not describe things well, it will be quickly replaced by a more effective category.

Meme theory suggests this directly–useful ideas spread faster than non-useful ideas. Useful categories get used. Useless categories get discarded. If I can’t talk about reality, then I need new words.

Sometimes, new information causes us to update our categories. For example, back before people figured out much about biology, fungi were a bit of a mystery. They clearly act like plants, but they aren’t green and they seem to grow parasitically out of dead things. Fungi were basically classed as “weird, creepy plants,” until we found out that they’re something else. It turns out that fungi are actually more closely related to humans than plants, but no one outside of a molecular biologist has any need for a category that is “humans and fungi, but not plants,” so no one uses such a category. There are, additionally, some weird plants, like venus flytraps, that show animal-like traits like predation and rapid movement, and some animals, like sponges, that look more like plants. You would not think a man crazy if he mistook a sponge for a plant, but no one looks at these examples, throws up their hands, and says, “Well, I guess plants and animals are arbitrary, socially-constructed categories and don’t exist.” No, we are all quite convinced that, despite a few cases that were confusing until modern science cleared them up, plants, animals, and fungi all actually exist–moving sponges from the “plant” category to the “animal” category didn’t discredit the entire notion of “plants” and “animals,” but instead improved our classification scheme.

Updating ideas and classification schemes slightly to make them work more efficiently as we get more information about obscure or edge cases in no way impacts the validity of the classification scheme. It just means that we’re human beings who aren’t always 100% right about everything the first time we behold it.

To summarize: reality exists, and it comes in lumps. We create words to describe it. If a word does not describe reality, it gets replaced by a superior word that does a better job of describing reality. Occasionally, we get lucky and find out more information about reality, and update our categories and words accordingly. Where a category exists and is commonly used, therefore, it most likely reflects an actual, underlying reality that existed before the world and caused it to come into existence–not the other way around.

The belief that words create reality is magical thinking and belongs over in Harry Potter and animist religion, where you can cure Yellow Fever by painting someone yellow and then washing off the paint. It’s the same childish thinking as believing that monsters can’t see you if you have a blanket over your head (because you can’t see them) or that Bloody Mary will appear in the bathroom mirror if you turn out the lights and say her name three times while spinning around.

Of course, “white privilege” is basically the “evil eye” updated for the modern age, so it’s not too surprised to find people engaged in other forms of mystical thinking, like that if you just don’t believe in race, it will cease to exist and no one will ever slaughter their neighbors again, just as no war ever happened before 1492 and Genghis Khan never went on a rampage that left 50 million people dead.

“Purity” as conceived of in these examples isn’t real. It doesn’t exist; it never existed, and outside of the simplistic explanations people thought up a few thousand years ago when they had much less information about the world, no one actually uses such definitions. The existence of different races doesn’t depend on Ham and Shem; rain doesn’t stop existing just because Zeus isn’t peeing through a sieve. In reality, men and women are different in a number of different ways that render categories like “man” and “woman” functional enough for 99.99% of your daily interactions. Racial categories like “black” and “white” reflect real-life differences between actual humans accurately enough that we find them useful terms, and the fact that humans have migrated back and forth across the planet, resulting in very interesting historical stories encoded in DNA, does not change this at all.

I’d like to wrap this up by returning to the BBC’s strange article on the Aryans:

I asked Dolma if she was excited over her daughter participating in the festival. She replied that not many outsiders came to Biama, and that it was fun to meet foreigners. But even more importantly, she couldn’t wait to see friends from neighbouring villages, brought together by each year by the festival, as well as the chance to dress up, dance and celebrate. If the future generations continue to hold traditional ceremonies and celebrations and keep their vibrant culture alive, perhaps then, they won’t be the last of the Aryans.

smallisland
Source:  The Economist

One wonders what the author–or the BBC in general–thinks of efforts to keep the British pure or preserve British culture, untouched and unchanged through the millennia. Or is preserving one’s culture only for quaint foreigners whose entertaining exoticism would be ruined if they started acting and dressing just like us? What about those of us in America who think the British have a quaint and amusing culture, and would like it to stick around so we can still be entertained by it? And do the British themselves deserve any say in this, or are they eternally tainted with “impure,” “tampered” bloodlines due to the mixing of bronze-age peoples with Anglo Saxon invaders over a millennium and a half ago, and thus have no right to claim a culture or history of their own?

Goodness, what an idiotic way of looking at the world.

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Pygmy-pocalypse?

I just want to highlight this graph I came across yesterday while trying to research archaic introgression in the Igbo:

Populationsize
source

From Whole-genome sequence analysis of a Pan African set of samples reveals archaic gene flow from an extinct basal population of modern humans into sub-Saharan populations, by Lorente-Galdos et al.

There are three versions of this graph in the paper (check the supplemental materials for two of them), all showing about the same thing. It is supposed to be a graph of population size at different times in the past, and the most incredible thing is that for the past 100,000 years or so, the most numerically dominant populations in Africa were the Baka Pygmies, followed by various Bushmen (San) groups. The authors write:

To unravel the ancient demographic history of the African populations that are present in our data set, we used the Pairwise Sequentially Markovian Coalescent (PSMC) model that analyzes the dynamics of the effective population size over time [60]. We included at least one representative of each of the 15 African populations and two Eurasian samples in the analysis (Additional file 1: Figure S7.1) and considered both the classical mutation rate of 2.5 × 10−8 [61] and the 1.2 × 10−8 mutations per bp per generation reported in other analyses [6263]. The demographic trajectories of the sub-Saharan agriculturalist populations are very similar to each other; and only South African Bantu and Toubou individuals differ partly from the rest of sub-Saharan farmer samples; however, their considerable levels of admixture with other North African or hunter-gatherer populations (Fig. 2b) might explain this trend. Therefore, in order to ease visualization, we plotted a Yoruba individual (Yoruba_HGDP00936) and two Ju|‘hoansi individuals as representatives of the sub-Saharan agriculturalist and Khoisan populations, respectively (Fig. 3 and Additional file 1: Figure S7.2 considering a mutation rate of 1.2 × 10−8).

The authors note that the apparent large size of the pygmy groups could have been due to groups splitting and merging and thus getting more DNA variety than they would normally. It’s all very speculative. But still, the Baka Pygmies could have been the absolutely dominant group over central Africa for centuries.

What happened?

 

Book Club: Chinua Achebe’s Things Fall Apart, pt 3/3

 

Chinua_Achebe_-_Buffalo_25Sep2008_crop
Chinua Achebe, Author and Nobel Prize winner

Welcome back to our discussion of Chinua Achebe’s Things Fall Apart. Today I wanted to take a closer look at some of the aspects of traditional Igbo society mentioned in the book.

If you are a regular reader of this blog, you know by now that just as early modern humans (Homo sapiens) mated with Neanderthals and Denisovans somewhere over in Eurasia, some sapiens mated with archaic humans in Africa.

Unfortunately, the state of knowledge about African genomes and especially archaic African genomes is very primitive. Not only does ancient DNA not preserve terribly well in many parts of Africa, but the continent is also rather poor and so people there don’t send their spit to 23 and Me very often to get DNA tested. Thus, sadly, I do not have archaic DNA percents for the Igbo.

WAfricaAdmixture
“Approximate Bayesian computation estimates for the introgressing population across four African populations (Yoruba from Ibadan (YRI), Esan in Nigeria [ESN], Gambian in Western Divisions in the Gambia [GWD], and Mende in Sierra Leone [MSL]),” from Recovering Signals of Ghost Archaic Introgression in African Populations
However, we do have data for their neighbors, the Yoruba, Esan, Mende, and Gambians.

Keep in mind that so far, Eurasians measure about 1-4% Neanderthal and Melanesians about 6% Denisovan, so 10% Ghost in west Africans is a pretty big deal (if you’re into archaic DNA.) The authors of the study estimate that the admixture occurred about 50,000 years ago, which is coincidentally about the same time as the admixture in non-Africans–suggesting that whatever triggered the Out of Africa migration may have also simultaneously triggered an Into Africa migration. 

If you’re not familiar with some of these groups (I only know a little about the Yoruba,) the Esan, Mende, Gambians, and Yoruba are all speakers of languages from the Niger-Congo family (of which the Bantu languages are a sub-set.) The Niger-Congo family is one of the world’s largest, with 1,540 languages and 700 million speakers. It spread within the past 3,000 years from a homeland somewhere in west Africa (possibly Nigeria) to dominate sub-Saharan Africa. As far as I can tell, the Igbo are quite similar genetically to the Yoruba, and the admixture event happened tens of thousands of years before these groups spread and split, so there’s a good chance that the Igbo have similarly high levels of ghost-pop admixture.

Interestingly, a population related to the Bushmen and Pygmies used to dominate central and southern Africa, before the Bantu expansion. While the Bantu expansion and the admixture event are separated by a good 40 or 50 thousand years, this still suggests the possibility of human hybrid vigor.

Edit: A new paper just came out! Whole-genome sequence analysis of a Pan African set of samples reveals archaic gene flow from an extinct basal population of modern humans into sub-Saharan populations:

Here, we examine 15 African populations covering all major continental linguistic groups, ecosystems, and lifestyles within Africa through analysis of whole-genome sequence data of 21 individuals sequenced at deep coverage. We observe a remarkable correlation among genetic diversity and geographic distance, with the hunter-gatherer groups being more genetically differentiated and having larger effective population sizes throughout most modern-human history. Admixture signals are found between neighbor populations from both hunter-gatherer and agriculturalists groups, whereas North African individuals are closely related to Eurasian populations. Regarding archaic gene flow, we test six complex demographic models that consider recent admixture as well as archaic introgression. We identify the fingerprint of an archaic introgression event in the sub-Saharan populations included in the models (~ 4.0% in Khoisan, ~ 4.3% in Mbuti Pygmies, and ~ 5.8% in Mandenka) from an early divergent and currently extinct ghost modern human lineage.

So the ghost population that shows up in the Pygmies the same ghost population as shows up in the Mende? Looks like it.

There’s a lot of interesting stuff in this paper, but I’d just like to highlight this one graph:

Populationsize

I don’t really understand how they compute these things, much less if this is accurate (though their present estimate for the size of the Han looks pretty good,) but assuming it is, we can say a few things: One, before 100,000 years ago, all of the groups–except the Laal of Chad–tracked closely together in size because they were one group. Most of the groups then got smaller simply because they split up. But there seems to have been some kind of really big population bottleneck a bit over a million years ago.

The other really interesting thing is the absolute Pygmy dominance of the mid-10,000-100,000 year range. The authors note:

It is noteworthy that we observed by PSMC a sudden Ne increase in Baka Pygmy around 30 kya. A similar increase was observed in another study that analyzed several Baka and Biaka samples [25]. In addition, this individual presents the highest average genome-wide heterozygosity compared to the rest of samples (Fig. 1b). Nevertheless, such abrupt Ne increase can be attributed to either a population expansion or episodes of separation and admixture [60]. Further analyses at population level are needed to distinguish between these two scenarios.

Until we get more information on the possible Pygmy-cide, let’s get back to Things Fall Apart, for the Igbo of 1890 aren’t their ancestors of 50,000 BC nor the conquerors of central Africa. Here’s an interesting page with information about some of the rituals Achebe wrote about, like the Feast of the New Yams and the Egwugwu ceremony:

 The egwugwu ceremony takes place in order to dispute the guilty side of a crime taken place, similar to our court trials… Nine egwugwu represented a village of the clan, their leader known as Evil Forest; exit the huts with their masks on.

Short page; fast read.

The egwugwu ceremony I found particularly interesting. Of course everyone knows the guys in masks are just guys in masks (well, I assume everyone knows that. It seems obvious,) yet in taking on the masks, they adopt a kind of veil of anonymity. In real life, they are people, with all of the biases of ordinary people; under the mask, they take on the identity of a spirit, free from the biases of ordinary people. It is similar to the official garb worn by judges in other countries, which often look quite silly (wigs on English barristers, for example,) but effectively demarcate a line between normal life and official pronouncements. By putting on the costume of the office, the judge becomes more than an individual.

I have long been fascinated by masks, masquerades, and the power of anonymity. Many famous writers, from Benjamin Franklin to Samuel Clemens, published under pseudonyms. The mask implies falseness–on Halloween, we dress up as things that we are not–but it also allows honesty by freeing us from the threat of retribution.

It is interesting that a small, tightly-knit society where everyone knows everyone and social relations are of paramount importance, like the Igbo, developed a norm of anonymizing judges in order to remove judicial decisions from normal social relations and obligations (as much as possible, anyway). Since most Igbo villages did not have kings or other aristocrats to dictate laws, rule was conducted by notable community members who had effectively purchased or earned noble titles. These nobles got to wear the masks and costumes of the egwgwu.

Ok, so it’s getting late and I need to wrap this up. This moment comes in every post.

I know I haven’t said much about the book itself. The plot, narrative, pacing, structure, writing style, etc. To be honest, that’s because I didn’t enjoy it very much. It was interesting for its content, along with a sense of “I’ve been trying to tell people this and I could have saved myself a lot of time by just pointing them to the book. And if this is a book taught in schools (we didn’t read it in my highschool, but I have heard that many people did,) then why aren’t people more aware of the contents?

What was tribal life like before the Europeans got there? Well, women got beaten a lot. Children were murdered to avenge tribal conflicts. Infant mortality was high. In other words, many things were pretty unpleasant.

And yet, interestingly, much of what we think was unpleasant about them was, in its own way, keeping the peace. As Will (Evolving Moloch) quotes from The Social Structure of Right and Wrong on Twitter:

“Much of the conduct described by anthropologists as conflict management, social control, or even law in tribal and other traditional societies is regarded as crime in modern [nation state] societies.” This is especially clear in the case of violent modes of redress such as assassination, feuding, fighting, maiming, and beating, but it also applies to the confiscation and destruction of property and to other forms of deprivation and humiliation. Such actions typically express a grievance by one person or group against another.

See, for example, when the village burned down Okonkwo’s house for accidentally killing a villager, when they burned down the church for “killing” a deity, or when they took a little girl and killed a little boy in revenge for someone in another village killing one of their women. To the villagers, these were all legal punishments, and the logic of burning down a person’s house if they have killed someone is rather similar to the logic of charging someone a fine for committing manslaughter. Even though Okonkwo didn’t mean to kill anyone, he should have been more careful with his gun, which he knew was dangerous and could kill someone.

Unlike penalties imposed by the state, however, private executions of this kind often result in revenge or even a feud—Moreover, the person killed in retaliation may not be himself or herself a killer, for in these societies violent conflicts between nonkin are virtually always handled in a framework of collective responsibility–or more precisely, collective liability–whereby all members of a social category (such as a family or lineage) are held accountable for the conduct of their fellows.

And, of course, penalties so meted out can be incredibly violent, arbitrary, and selfish, but ignoring that, there’s clearly a conflict when traditional, tribal ways of dealing with problems clash with state-based ways of dealing with problems. Even if everyone eventually agrees that the state-based system is more effective (and I don’t expect everyone to agree) the transition is liable to be difficult for some people, especially if, as in the book, they are punished by the state for enforcing punishments prescribed by their own traditional laws. The state is effectively punishing them for punishing law-breakers, creating what must seem to them a state of anarcho-tyranny.

As for polygamy, Achebe seems to gloss over some of its downsides. From Christakis’s Blueprint: The Origins of a Good Society (h/t Rob Henderson), we have:

Co-wife conflict is ubiquitous in polygynous households… Because the Turkana often choose wives from different families in order to broaden their safety net, they typically do not practice sororal [sister-wives] polygyny… When co-wives are relatives, they can more easily share a household and cooperate… But while sororal polygyny is especially common in cultures in the Americas, general polygyny tends to be the usual pattern in Africa. An examination of ethnographic data from 69 nonsororal polygynous cultures fails to turn up a single society where co-wife relations could be described as harmonious. Detailed ethnographic studies highlight the stresses and fears present in polygynous families, including, for example, wives’ concern that other wives might try to poison their children so that their own children might inherit land or property.

Anyway, let’s wrap this up with a little article on human pacification:

There is a well-entrenched schism on the frequency (how often), intensity (deaths per 100,000/year), and evolutionary significance of warfare among hunter-gatherers compared with large-scale societies. To simplify, Rousseauians argue that warfare among prehistoric and contemporary hunter-gatherers was nearly absent and, if present, was a late cultural invention. In contrast, so-called Hobbesians argue that violence was relatively common but variable among hunter-gatherers. … Furthermore, Hobbesians with empirical data have already established that the frequency and intensity of hunter-gatherer warfare is greater compared with large-scale societies even though horticultural societies engage in warfare more intensively than hunter-gatherers. In the end I argue that although war is a primitive trait we may share with chimpanzees and/or our last common ancestor, the ability of hunter-gatherer bands to live peaceably with their neighbors, even though war may occur, is a derived trait that fundamentally distinguishes us socially and politically from chimpanzee societies. It is a point often lost in these debates.

I think we should read Legal Systems Very Different from Ours for our next book. Any other ideas?

What Ethic Group is This?

 

map

23 and Me map of genetic relatives, rounded. 

An ethnic group is a set of people with a common ancestry, culture, and language. The Han Chinese, at a 1.3 billion strong, are an ethnic group; the Samaritans, of whom there are fewer than a thousand, are also an ethnic group. Ishi was, before his death, an ethnic group of one: the last surviving member of the Yahi people of California. 

We sit within nested sets of genetic relatives:

Family<clan<tribe<ethnic group<race<species<genus

(You are most likely part Homo neanderthalensis, because different species within the Homo genus have interbred multiple times.)

Interestingly, Wikipedia lists African American as an ethnicity on its list of ethnic groups page (as they should, because it is). 

Four or five hundred relatives, from parents and children to fifth cousins, are enough to begin to describe an ethnic group. It certainly looks, based on the map, like I hail from an ethnic group–yet neither Wikipedia nor 23 and Me recognize this group.

According to Wikipedia

Larger ethnic groups may be subdivided into smaller sub-groups known variously as tribes or clans, which over time may become separate ethnic groups themselves due to endogamy or physical isolation from the parent group. Conversely, formerly separate ethnicities can merge to form a pan-ethnicity, and may eventually merge into one single ethnicity. Whether through division or amalgamation, the formation of a separate ethnic identity is referred to as ethnogenesis.

Of course, no one wants to submit their DNA to 23 and Me and get the result “You’re a white person from America.” (Nor “You’re a black person from America.”) We know that. People take these tests to look at their deeper history. 

But focusing only on the past makes it easy to lose sight of the present. You aren’t your ancestors. The world didn’t halt in 1492. I’m no more “British” or “European” than I am “Yamnaya” or “Anatolian farmer.” 

History moves on. New ethnic groups form. The past tells us something about where we’ve been–but not where we’re headed. 

What does “Heritable” mean? 

“Heritable” (or “heritability”) has a specific and unfortunately non-obvious definition in genetics.

The word sounds like a synonym for “inheritable,” rather like your grandmother’s collection of musical clocks. Musical clocks are inheritable; fruit, since it rots, is not very inheritable.

This is not what “heritable” means.

“Heritability,” in genetics, is a measure of the percent of phenotypic variation within a population that can be attributed to genetics.

Let me clarify that in normal speak. “Phenotype” is something you can actually see about an organism, like how tall it is or the nest it builds. “Phenotypic variation” means things like “variation in height” or “variation in nest size.”

Let’s suppose we have two varieties of corn: a giant strain and a dwarf strain. If we plant them in a 100% even field with the same nutrients, water, sunlight, etc at every point in the field, then close to 100% of the variation in the resulting corn plants is genetic (some is just random chance, of course.)

In this population, then, height is nearly 100% heritable.

Let’s repeat the experiment, but this time, we sow our corn in an irregular field. Some patches have good soil; some have bad. Some spots are too dry or too wet. Some are sunny; others shaded. Etc.

Here it gets interesting, because aside from a bit of random chance in the distribution of seeds and environmental response, in most areas of the irregular field, our “tall” corn is still taller than the “short” corn. In the shady areas, both varieties don’t get enough sun, but the tall corn still grows taller. In the nutrient-poor areas, both varieties don’t get enough nutrients, but the tall still grows taller. But when we compare all of the corn all over the field, dwarf corn grown in the best areas grows taller than giant corn grown in the worst areas.

Our analysis of the irregular field leads us to conclude that water, sunlight, nutrients, and genes are all important in determining how tall corn gets.

Height in the irregular field is still heritable–genes are still important–but it is not 100% heritable, because other stuff is important, too.

What does it mean to be 10, 40, or 80% heritable?

If height is 10% heritable, then most of the variety in height you see is due to non-genetic factors, like nutrition. Genes still have an effect–people with tall genes will still, on average, be taller–but environmental effects really dominate–perhaps some people who should have been tall are severely malnourished.

In modern, first world countries, height is about 80% heritable–that is, since most people in first world countries get plenty of food and don’t catch infections that stunt their growth, most of the variation we see is genetic. In some third world countries, however, the heritability of height drops to 65%. These are places where many people do not get the nutrients they need to achieve their full genetic potential.

How do you achieve 0% heritability?

A trait is 0% heritable not if you can’t inherit it, but if genetics explains none of the variation in the sample. Suppose we seeded an irregular field entirely with identical, cloned corn. The height of the resulting corn would would vary from area to area depending on nutrients, sunlight, water, etc. Since the original seeds were 100% genetically identical, all of the variation is environmental. Genes are, of course, important to height–if the relevant genes disappeared from the corn, it would stop growing–but they explain none of the variation in this population.

The heritability of a trait decreases, therefore, as genetic uniformity increases or the environment becomes more unequal. Heritability increases as genetics become more varied or the environment becomes more equal. 

Note that the genes involved do not need to code directly for the trait being measured. The taller people in a population, for example, might have lactase persistence genes, which let them extract more calories from the milk they drink than their neighbors. Or they might be thieves who steal food from their neighbors.

I remember a case where investigators were trying to discover why most of the boys at an orphanage had developed pellagra, then a mystery disease, but some hadn’t. It turns out that the boys who hadn’t developed it were sneaking into the kitchen at night and stealing food.

Pellagra is a nutritional deficiency caused by lack of niacin, aka B3. Poor Southerners used to come down with it from eating diets composed solely of (un-nixtamalized) corn for months on end.

The ultimate cause of pellagra is environmental–lack of niacin–but who comes down with pellagra is at least partially determined by genes, because genes influence your likelihood of eating nothing but corn for 6 months straight. Sociopaths who steal the occasional ham, for example, won’t get pellagra, but sociopaths who get caught and sent to badly run prisons, however, increase their odds of getting it. In general, smart people who work hard and earn lots of money significantly decrease their chance of getting it, but smart black people enslaved against their will are more likely to get it. So pellagra is heritable–even though it is ultimately a nutritional deficiency.

What’s the point of heritability?

If you’re breeding corn (or cattle,) it helps to know whether, given good conditions, you can hope to change a trait. Traits with low heritability even under good conditions simply can’t be affected very much by breeding, while traits with high heritability can.

In humans, heritability helps us seek out the ultimate causes of diseases. On a social level, it can help measure how fair a society is, or whether the things we are doing to try to make society better are actually working.

For example, people would love to find a way to make children smarter. From Baby Einstein to HeadStart, people have tried all sorts of things to raise IQ. But beyond making sure that everyone has enough to eat, no nutrient deficiencies, and some kind of education, few of these interventions seem to make much difference.

Here people usually throw in a clarification about the difference between “shared” and “non-shared” environment. Shared environment is stuff you share with other members of your population, like the house your family lives in or the school you and your classmates attend. Non-shared is basically “random stuff,” like the time you caught meningitis but your twin didn’t.

Like anything controversial, people of course argue about the methodology and mathematics of these studies. They also argue about proximate and ultimate causes, and get caught up matters of cultural variation. For example, is wearing glasses heritable? Some would say that it can’t be, because how can you inherit a gene that somehow codes for possessing a newly invented (on the scale of human evolutionary history) object?

But this is basically a fallacy that stems from mixing up proximate and ultimate causes. Obviously there is no gene that makes a pair of glasses grow out of your head, nor one that makes you feel compelled to go and buy them. It is also obvious that not all human populations throughout history have had glasses. But within a population that does have glasses, the chances of you wearing glasses is strongly predicted by whether or not you are nearsighted, and nearsightedness is a remarkable 91% heritable. 

Of course, some nearsighted people opt to wear contact lenses, which lowers the heritability estimate for glasses, but the signal is still pretty darn strong, since almost no one who doesn’t have vision difficulties wears glasses.

If we expand our sample population to include people who lived before the invention of eyeglasses, or who live in countries where most people are too poor to afford glasses, then our heritability estimate will drop quite a bit. You can’t buy glasses if they don’t exist, after all, no matter how bad your eyesight it. But the fact that glasses themselves are a recent artifact of particular human cultures does not change the fact that, within those populations, wearing glasses is heritable.

“Heritability” does not depend on whether there is (or we know of ) any direct mechanism for a gene to code for the thing under study. It is only a statistical measure of genetic variation that correlates with the visible variation we’re looking at in a population.

I hope this helps.

Links Post: Evolution and More

road-to-bigger-brains
From State of the Science: Finding Human Ancestors in New Places

The Puerto Rican rainforest is beautiful and temporarily low on bugs. (Bugs, I suspect, evolve quickly and so can bounce back from these sorts of collapses–but they are collapses.)

More evidence for an extra Neanderthal or Denisovan interbreeding event in East Asians and Melanesian genomes:

 In addition to the reported Neanderthal and Denisovan introgressions, our results support a third introgression in all Asian and Oceanian populations from an archaic population. This population is either related to the Neanderthal-Denisova clade or diverged early from the Denisova lineage.

(Congratulations to the authors, Mondal, Bertranpetit, and Lao.)

Really interesting study on gene-culture co-evolution in Northeast Asia:

Here we report an analysis comparing cultural and genetic data from 13 populations from in and around Northeast Asia spanning 10 different language families/isolates. We construct distance matrices for language (grammar, phonology, lexicon), music (song structure, performance style), and genomes (genome-wide SNPs) and test for correlations among them. … robust correlations emerge between genetic and grammatical distances. Our results suggest that grammatical structure might be one of the strongest cultural indicators of human population history, while also demonstrating differences among cultural and genetic relationships that highlight the complex nature of human cultural and genetic evolution.

I feel like there’s a joke about grammar Nazis in here.

Why do we sleep? No one knows.

While humans average seven hours, other primates range from just under nine hours (blue-eyed black lemurs) to 17 (owl monkeys). Chimps, our closest living evolutionary relatives, average about nine and a half hours. And although humans doze for less time, a greater proportion is rapid eye movement sleep (REM), the deepest phase, when vivid dreams unfold.

Sleep is pretty much universal in the animal kingdom, but different species vary greatly in their habits. Elephants sleep about two hours out of 24; sloths more than 15. Individual humans vary in their sleep needs, but interestingly, different cultures vary greatly in the timing of their sleep, eg, the Spanish siesta. Our modern notion that people “should” sleep in a solid, 7-9 hour chunk (going so far as to “train” children to do it,) is more a result of electricity and industrial work schedules than anything inherent or healthy about human sleep. So if you find yourself stressed out because you keep taking a nap in the afternoon instead of sleeping through the night, take heart: you may be completely normal. (Unless you’re tired because of some illness, of course.)

Interestingly:

Within any culture, people also prefer to rest and rise at different times: In most populations, individuals range from night owls to morning larks in a near bell curve distribution. Where someone falls along this continuum often depends on sex (women tend to rise earlier) and age (young adults tend to be night owls, while children and older adults typically go to bed before the wee hours).

Genes matter, too. Recent studies have identified about a dozen genetic variations that predict sleep habits, some of which are located in genes known to influence circadian rhythms.

While this variation can cause conflict today … it may be the vestige of a crucial adaptation. According to the sentinel hypothesis, staggered sleep evolved to ensure that there was always some portion of a group awake and able to detect threats.

So they gave sleep trackers to some Hadza, who must by now think Westerners are very strange, and found that at any particular period of the night, about 40% of people were awake; over 20 nights, there were “only 18 one-minute periods” when everyone was asleep. That doesn’t prove anything, but it does suggest that it’s perfectly normal for some people to be up in the middle of the night–and maybe even useful.

Important dates in the evolution of human brain genes found:

In May, a pair of papers published by separate teams in the journal Cell focused on the NOTCH family of genes, found in all animals and critical to an embryo’s development: They produce the proteins that tell stem cells what to turn into, such as neurons in the brain. The researchers looked at relatives of the NOTCH2 gene that are present today only in humans.

In a distant ancestor 8 million to 14 million years ago, they found, a copying error resulted in an “extra hunk of DNA,” says David Haussler of the University of California, Santa Cruz, a senior author of one of the new studies.

This non-functioning extra piece of NOTCH2 code is still present in chimps and gorillas, but not in orangutans, which went off on their own evolutionary path 14 million years ago.

About 3 million to 4 million years ago, a few million years after our own lineage split from other apes, a second mutation activated the once non-functional code. This human-specific gene, called NOTCH2NL, began producing proteins involved in turning neural stem cells into cortical neurons. NOTCH2NL pumped up the number of neurons in the neocortex, the seat of advanced cognitive function. Over time, this led to bigger, more powerful brains. …

The researchers also found NOTCH2NL in the ancient genomes of our closest evolutionary kin: the Denisovans and the Neanderthals, who had brain volumes similar to our own.

And finally, Differences in Genes’ Geographic Origins Influence Mitochondrial Function:

“Genomes that evolve in different geographic locations without intermixing can end up being different from each other,” said Kateryna Makova, Pentz Professor of Biology at Penn State and an author of the paper. “… This variation has a lot of advantages; for example, increased variation in immune genes can provide enhanced protection from diseases. However, variation in geographic origin within the genome could also potentially lead to communication issues between genes, for example between mitochondrial and nuclear genes that work together to regulate mitochondrial function.”

Researchers looked at recently (by evolutionary standards) mixed populations like Puerto Ricans and African Americans, comparing the parts of their DNA that interact with mitochondria to the parts that don’t. Since mitochondria hail from your mother, and these populations have different ethnic DNA contributions along maternal and paternal lines. If all of the DNA were equally compatible with their mitochondria, then we’d expect to see equal contributions to the specifically mitochondria-interacting genes. If some ethnic origins interact better with the mitochondria, then we expect to see more of this DNA in these specific places.

The latter is, in fact, what we find. Puerto Ricans hail more from the Taino Indians along their mtDNA, and have relatively more Taino DNA in the genes that affect their mitochondria–indicating that over the years, individuals with more balanced contributions were selected against in Puerto Rico. (“Selection” is such a sanitized way of saying they died/had fewer children.)

This indicates that a recently admixed population may have more health issues than its parents, but the issues will work themselves out over time.

Review: The Blank Slate, by Steven Pinker 5/5 Stars

Steven Pinker’s The Blank Slate was one of my top reads of 2018. Simultaneously  impassioned, philosophic, and rational, Pinker covers everything from art to parenting, morality to language. What makes us us? Where does human nature–and individual personality–come from? And what are the moral implications if blank slateist views of human nature are false?

Yes, Pinker writes from a liberal perspective, for a liberal audience–Pinker hails from a liberal culture and addresses the members of his own culture, just as a French writer addresses a French audience. But this is about as far as conventions like “left” and “right” can take you in this book, for it is clear that Pinker thinks breaking down political ideology and morality based on the seating patterns of an eighteenth-century French legislature is not terribly meaningful. 

Is the blank slate–the idea that humans are born essentially similar in personality, temperament, abilities, and potential, and that environmental plays a substantial role in determining whether we turn out to be Nobel Prize winners or drag queens, Jeff Bezos or homeless, criminals or lion tamers–moral? 

Its adherents claim that it is–indeed, some react to any suggestion that humans have any innate or biological nature with a vehemence normally reserved for rapists and murderers. 

Pinker responds that the denial of human nature causes unimaginable suffering. Humans cannot cast aside their natures simply because an ideology (or religion) tells them to. To attempt to remake man is to destroy him. 

Further, it is blatantly untrue, and the promotion of obvious lies in pursuit of ideological outcomes is bound to backfire–turning people away from the academics and fields that promote such lies. (Pinker may be overly optimistic on this point.) 

Chapter 1 is a bit slow if you are already familiar with the history of psychology and the blank slate in philosophy, but after that it picks up nicely. 

There is an unstated conclusion we may draw here that psychology as a discipline has been hampered by the kinds of people who go into the psychology. Perhaps this is my own theory I am imposing onto Pinker’s work, but it seems like people with a good, intuitive grasp of how people work don’t go into psychology–they go into sales. The folks in psychology (and psychiatry, perhaps) seem drawn to the field because they find people mysterious and fascinating and want to understand them better. 

But without an intuitive understanding of how people work, there are often big areas they miss. 

Since I listened to this in audio book format, quoting is tricky, but I have tried to transcribe this bit:

Until recently, psychology ignored the content of beliefs and emotions, and the possibility that the mind had evolved to treat biologically important categories in different ways. … Theories about memory and reasoning didn’t distinguish between thoughts about people and thoughts about rocks or houses. Theories of emotion didn’t distinguish fear from anger, jealousy, or love. Theories of social relation didn’t distinguish between family, friends, enemies, and strangers.

Indeed, the topics in psychology that most interest lay people–love, hate, work, play, food, sex, status, dominance, jealousy, friendship, religion, art–are almost completely absent from psychology textbooks.

It’s hard to see what you can’t see.

The field was also historically rather short on women, especially women with normal lives. Many of these blank slateist quotes from psychologists and philosophers about human nature and instincts seem like the kinds of ideas that raising a few children would quickly disabuse you of.  

Next he discusses Durkheim’s observation that people behave differently in groups than they do singly or would behave had they not been part of a group. From this I think Durkheim derives his idea that “human nature” and “human behavior” are not innate or instinctive, but culturally induced. 

Some years ago, I realized there is probably an important key to human behavior that is rarely explicitly discussed because if you have it, it is so obvious that you don’t even notice it, and if you don’t have it, it’s so non-obvious that you can’t figure it out: an imitation instinct.

People desire to be like the people around them, and for probably evolutionarily sound reasons. 

If everyone else in your tribe says, “Don’t drink that water, it’s bad,” you’re better off avoiding the water than taking your chances by doing an independent test on the water. If your tribe has a longstanding tradition of “don’t eat the red berries, no I don’t know why, grandpa just told me to never ever eat them,” it’s probably best to go along. As Chesterton says, don’t tear down a fence if you don’t know why it’s there. 

I think a compulsion to fit in, imitate, and go along with others is very deep. It’s probbly not something people are explicitly aware of most of the time. This results in people using arguments like “That’s weird,” to mean, “That’s bad,” without explaining why “weird” is bad. They just intuitively know, and expect that you understand and agree with the speaker’s intuition that weird and different are inherently bad things. 

This leads to 1. self-policing–people feel very out of place when they aren’t going along with the group and this can make them deeply unhappy; and 2. other-policing–people feel unhappy just looking at someone else who is out of place, and this makes them respond with anger, hostility, and sometimes even violence toward the other person. (Even when what that other person is doing is really quite inconsequential and harmless.)

Anyway, I think Durkheim has missed that step–that connection between group activity and individual activity.

Obviously people are shaped by their groups, since most hunter-gatherer babies grow up to be hunter-gatherers and most people in our society grow up and figure out how to use cell phones and computers and cars. But I think he has missed the importance of–and critically, the usefulness of–the underlying mental trait that lets us learn from our cultures.

So people don’t behave differently in groups than when they’re alone because they lack some inherent human nature, but because part of our nature compels us to act in concordance with our group. (Most of us, anyway.) 

(This is about where I stopped taking notes, so I’m working from memory.)

Pinker then discusses the neurology of learning–how do we learn language? How does the brain know that language is something we are supposed to learn? How do we figure out that the family pet is not named “No no bad dog, get off the sofa”? 

There are some interesting experiments done on mice and kittens where experimenters have done things like reverse the parts of the brain auditory or visual inputs go to, or raise the kittens in environments without vertical lines and then introduce them to vertical lines, etc. The brain shows a remarkable plasticity under very strange conditions–but as Pinker points out, these aren’t conditions humans normally encounter. 

Sure, you can teach people to be afraid of flowers or like snakes, but it is much, much easier to teach people to like flowers and be afraid of snakes. 

Pinker points to the ease with which we learn to fear some objects but not others; the ease with which we learn to talk (except for those of us with certain neurological disorders, like brain damage or autism) verses the difficulty we have learning other things, like calculus; the rapidity with which some behaviors emerge in infancy or childhood (like aggression) verses the time it takes to instill other behaviors (like sharing) in children. 

In short, we appear to come into this world equipped to learn certain things, to respond to certain stimuli, and behave in particular ways. Without this basic wiring, we would not have any instinct for imitation–and thus babies would not coo in response to their mothers, would not start babbling in imitation of the adults around them, and would not learn to talk. We would not stand up and begin to walk–and it would be just as easy to train people to enjoy being victims of violence as to train people not to commit violence. 

Throughout the book, Pinker discusses the response of the more extreme left–people whom we today call SJWs or antifa–to the work and theories put out by academics who are undoubtedly also culturally liberal, like Napoleon Chagnon, the famous anthropologist who studied the Yanomamo tribesmen in the Amazon. For his meticulous work documenting Yanomamo family trees and showing that the Yanomamo men who killed more people wound up wound up with more children than the men who killed fewer people, he was accused by his fellow academics of all sorts of outlandish crimes.

In one absurd case, he was accused of intentionally infecting the Yanomamo with measles in order to test a theory that Yanomamo men had more “dominant genes,” which would give them a survival advantage over the measles. This is a serious accusation because exposure to Western diseases tends to kill off the majority of people in isolated, indigenous tribes, and absurd because “dominant genes” don’t confer any more or less immunity to disease. The accuser in this case has completely misunderstood the meaning of a term over in genetics. (It is rather like someone thinking the word “straight” implies that heterosexuals are supposed to have straighter bones than homosexuals, and then accusing scientists of going around measuring people’s bones to determine if they are gay or not.)

The term “dominant” does not mean that a gene gives a person any form of “dominance” in the real world. It just means that in a pair of genes, a “dominant” one gets expressed. The classic example is blue verses brown eyes. If you have one gene for blue eyes from one parent, and one for brown eyes from your other parent, anyone looking at you will just see brown eyes because only that gene gets used. However, you might still pass on that blue eye gene to your children, and if they receive another blue gene from your spouse, they could have blue eyes. Since blue eyes only show up if both of a person’s eye color genes are blue, we call blue eyes “recessive.” 

But having a “dominant” gene for eye color doesn’t make someone any more “dominant” in real life. It doesn’t make you better at beating people up or surviving the flu–and nothing about the Yanomamo lifestyle suggests that they would have more “dominant genes” than anyone else in the world. 

Side note: this strange misconception of how genes work made it into Metal Gear Solid: 

“I got all of the recessive genes! You took everything from me before I was even born!”

The fact that the far left often engages in outright lies to justify real violence against the people they dislike–people who aren’t even conservatives on the American scale–makes one wonder why Pinker identifies at all with the left’s goals, but I suppose one can’t help being a part of one’s own culture. If a Frenchman objects to something happening in France, that doesn’t turn him into a German; a Christian doesn’t stop believing in Jesus just because he objects to Fred Phelps. 

The book came out in 2002, before “antifa” became a household term. I think Pinker expected the evils of communism to become more widely known–not less. 

There is an interesting discussion of E. O. Wilson’s Sociobiology and how a better understanding of human family dynamics (especially whether they become controlling and harmful) could improve women’s lives, not harm them. (Wilson’s work I would like to explore in more depth.) 

Pinker proceeds to a moving chapter parenting (I teared up at the end, though that might have just been the effects of several days of inadequate sleep.) How much effect do parents have on how their children turn out? At least within the normal range of parenting, not much–kids seem to turn out as they will, despite our best efforts. Sure, there’s plenty of evidence that you can damage kids by shaking them, dropping them on their heads, or locking them in the closet for years–but this is not normal parenting. Meanwhile, there’s very little evidence in favor of any interventions that can raise a child’s IQ (or any other trait) above what it would have been otherwise. It’s much easier to break a complicated system than enhance it. 

People often respond along the lines of “If I cannot shape my children like clay, determining how they turn out as adults, what’s the point of parenting at all?” 

It’s a terrible response, as Pinker points out. Children are human and deserve to be valued for the people they are (and will be,) not because you can change them. You are not kind to your spouse because you expect to change them, after all, but because you like them and value them. Likewise, be kind to your children because you love and value them, not because you can program them like tiny computers. 

In search of the reasons people turn out the way they do, Pinker (and other writers) turns to the random effects of “the environment”–things like “the friends you had in highschool.” Certainly environment explains a good deal, like what language you speak or what job options exist in your society, but I think he neglects an alternative possibility for some traits: random chance. There are aspects of us that are just “who we are” and aren’t obviously determined by anything external. One child loves dogs, another horses. One person enjoys swimming, another biking, a third Candy Crush. 

Here a religious person might posit a “soul” or some other inner essence. 

The difficulty with the theory that children take after their peers–they do what it takes to fit in with their friends–is it neglects the question of why a child becomes friends with a particular group of other children in the first place. I don’t know about you, but my friends aren’t chosen randomly from the people around me, but tend to be people I have something in common with or enjoy being around in the first place. 

At any rate, it is certainly possible for well-meaning parents to isolate a child from peers and friends in an attempt to alter personalty traits that are actually innate, or at least not caused by those other children.

The meat of the book wraps up with a discussion of “modern art” and why it is terrible. 

Overall, it was an excellent book that remains fresh despite its age. 

Book Club: The 10,000 Year Explosion pt 7: Finale

 

Niels Bohr
Niels Bohr: 50% Jewish, 100% Quantum Physics

Chapter 7 of The 10,000 Year Explosion is about the evolution of high Ashkenazi IQ; chapter 8 is the Conclusion, which is just a quick summary of the whole book. (If you’re wondering if you would enjoy the book, try reading the conclusion and see if you want to know more.)

This has been an enjoyable book. As works on human evolution go, it’s light–not too long and no complicated math. Pinker’s The Blank Slate gets into much more philosophy and ethics. But it also covers a lot of interesting ground, especially if you’re new to the subject.

I have seen at least 2 people mention recently that they had plans to respond to/address Cochran and Harpending’s timeline of Jewish history/evolution in chapter 7. I don’t know enough to question the story, so I hope you’ll jump in with anything enlightening.

The basic thesis of Chapter 7 is that Ashkenazi massive over-representation in science, math, billionaires, and ideas generally is due to their massive brains, which is due in turn to selective pressure over the past thousand years or so in Germany and nearby countries to be good at jobs that require intellect. The authors quote the historian B. D. Weinryb:

More children survived to adulthood in affluent families than in less affluent ones. A number of genealogies of business leaders, prominent rabbis, community leaders, and the like–generally belonging to the more affluent classes–show that such people often had four, six, sometimes even eight or nice children who reached adulthood…

800px-Niels_Bohr_Albert_Einstein_by_Ehrenfest
Einstein and Bohr, 1925

Weinryb cites a census of the town of Brody, 1764: homeowner household had 1.2 children per adult; tenant households had only 0.6.

As evidence for this recent evolution, the authors point to the many genetic diseases that disproportionately affect Ashkenazim:

Tay-Sachs disease, Gaucher’s disease, familial dysautonomia, and two different forms of hereditary breast cancer (BRCA1 and BRCA2), and these diseases are up to 100 times more common in Ashkenazi Jews than in other European populations. …

In principle, absent some special cause, genetic diseases like these should be rare. New mutations, some of which have bad effects, appear in every generation, but those that cause death or reduced fertility should be disappearing with every generation. … one in every twenty-five Ashkenazi Jews carries a copy of the Tay-Sachs mutation, which kills homozygotes in early childhood. This is an alarming rate.

What’s so special about these diseases, and why do the Ashkenazim have so darn many of them?

Some of them look like IQ boosters, considering their effects on the development of the central nervous system. The sphingolipid mutations, in particular, have effects that could plausibly boost intelligence. In each, there is a buildup of some particular sphingolipid, a class of modified fat molecules that play a role in signal transmission and are especially common in neural tissues. Researchers have determined that elevated levels of those sphingolipids cause the growth of more connections among neurons..

There is a similar effect in Tay-Sachs disease: increased levels of a characteristic storage compound… which causes a marked increase in the growth of dendrites, the fine branches that connect neurons. …

We looked at the occupations of patients in Israel with Gaucher’s disease… These patients are much more likely to be engineers or scientists than the average Israeli Ashkenazi Jew–about eleven times more likely, in fact.

Einstein_oppenheimer
Einstein and Oppenheimer, Father of the Atomic Bomb, c. 1950

Basically, the idea is that similar to sickle cell anemia, being heterozygous for one of these traits may make you smarter–and being homozygous might make your life considerably shorter. In an environment where being a heterozygous carrier is rewarded strongly enough, the diseases will propagate–even if they incur a significant cost.

It’s a persuasive argument.

I’d like to go on a quick tangent to Von Neumann’s Wikipedia page:

Von Neumann was a child prodigy. When he was 6 years old, he could divide two 8-digit numbers in his head [14][15] and could converse in Ancient Greek. When the 6-year-old von Neumann caught his mother staring aimlessly, he asked her, “What are you calculating?”[16]

Children did not begin formal schooling in Hungary until they were ten years of age; governesses taught von Neumann, his brothers and his cousins. Max believed that knowledge of languages in addition to Hungarian was essential, so the children were tutored in English, French, German and Italian.[17] By the age of 8, von Neumann was familiar with differential and integral calculus,[18] but he was particularly interested in history. He read his way through Wilhelm Oncken‘s 46-volume Allgemeine Geschichte in Einzeldarstellungen.[19] A copy was contained in a private library Max purchased. One of the rooms in the apartment was converted into a library and reading room, with bookshelves from ceiling to floor.[20]

JohnvonNeumann-LosAlamos
Von Neumann

Von Neumann entered the Lutheran Fasori Evangélikus Gimnázium in 1911. Wigner was a year ahead of von Neumann at the Lutheran School and soon became his friend.[21] This was one of the best schools in Budapest and was part of a brilliant education system designed for the elite. Under the Hungarian system, children received all their education at the one gymnasium. Despite being run by the Lutheran Church, the school was predominately Jewish in its student body [22] The school system produced a generation noted for intellectual achievement, which included Theodore von Kármán (b. 1881), George de Hevesy (b. 1885), Leó Szilárd (b. 1898), Dennis Gabor (b. 1900), Eugene Wigner (b. 1902), Edward Teller (b. 1908), and Paul Erdős (b. 1913).[23] Collectively, they were sometimes known as “The Martians“.[24] 

One final thing in The 10,000 Year Explosion jumped out at me:

There are also reports of individuals with higher-than-average intelligence who have nonclassic congenital adrenal hyperplasia (CAH)… CAH, which causes increased exposure of the developing fetus to androgens (male sex hormones), is relatively mild compared to diseases like Tay-Sachs. At least seven studies show high IQ in CAH patients, parents, and siblings, ranging from 107 to 113. The gene frequency of CAH among the Ashkenazim is almost 20 percent.

Holy HBD, Batman, that’ll give you a feminist movement.

If you haven’t been keeping obsessive track of who’s who in the feminist movement, many of the early pioneers were Jewish women, as discussed in a recent article by the Jewish Telegraph Agency, “A History of the Radical Jewish Feminists and the one Subject they Never Talked About“:

Heather Booth, Amy Kesselman, Vivian Rothstein and Naomi Weisstein. The names of these bold and influential radical feminists may have faded in recent years, but they remain icons to students of the women’s liberation movement …

The Gang of Four, as they dubbed themselves, were among the founders of Chicago’s Women’s Liberation Union. …

Over weeks, months and years, no subject went unturned, from the political to the sexual to the personal. They were “ready to turn the world upside down,” recalled Weisstein, an influential psychologist, neuroscientist and academic who died in 2015.

But one subject never came up: the Jewish backgrounds of the majority of the group.

“We never talked about it,” Weisstein said.

Betty Friedan was Jewish; Gloria Steinem is half Jewish. There are a lot of Jewish feminists.

Of course, Jews are over-represented in pretty much every intellectual circle. Ayn Rand, Karl Marx, and Noam Chomsky are all Jewish. Einstein and Freud were Jewish. I haven’t seen anything suggesting that Jews are more over-represented in feminism than in any other intellectual circle they’re over-represented in. Perhaps they just like ideas. Someone should come up with some numbers.

Here’s a page on Congenital Adrenal Hyperplasia. The “classic” variety is often deadly, but the non-classic (the sort we are discussing here) doesn’t kill you.

Paul_Erdos_with_Terence_Tao
Paul Erdős with Terrence Tao, 1984 (Tao isn’t Jewish, of course.)

I’ve long suspected that I know so many trans people because some intersex conditions result in smarter brains (in this case, women who are better than average at math.) It looks like I may be on the right track.

Well, that’s the end of the book. I hope you enjoyed it. What did you think? And what should we read next? (I’m thinking of doing Pinker’s Blank Slate.)

Book Club: The 10,000 Year Explosion pt. 6: Expansion

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Welcome back to the Book Club. Today we’re discussing chapter 6 of Cochran and Harpending’s The 10,000 Year Explosion: Expansions

The general assumption is that the winning advantage is cultural–that is to say, learned. Weapons, tactics, political organization, methods of agriculture: all is learned. The expansion of modern humans is the exception to the rule–most observers suspect that biological difference were the root cause of their advantage. … 

the assumption that more recent expansions are all driven by cultural factors is based on the notion that modern humans everywhere have essentially the same abilities. that’s a logical consequence of human evolutionary stasis” If humans have not undergone a significant amount of biological change since the expansion out of Africa, then people everywhere would have essentially the same potentials, and no group would have a biological advantage over its neighbors. But as we never tire of pointing out, there has been significant biological change during that period.

I remember a paper I wrote years ago (long before this blog) on South Korea’s meteoric economic rise. In those days you had to actually go to the library to do research, not just futz around on Wikipedia. My memory says the stacks were dimly lit, though that is probably just some romanticizing. 

I poured through volumes on 5 year economic plans, trying to figure out why South Korea’s were more successful than other nations’. Nothing stood out to me. Why this plan and not this plan? Did 5 or 10 years matter? 

I don’t remember what I eventually concluded, but it was probably something along the lines of “South Korea made good plans that worked.” 

People around these parts often criticize Jared Diamond for invoking environmental explanations while ignoring or directly counter-signaling their evolutionary implications, but Diamond was basically the first author I read who said anything that even remotely began to explain why some countries succeeded and others failed. 

Environment matters. Resources matter. Some peoples have long histories of civilization, others don’t. Korea has a decently long history. 

Diamond was one of many authors who broke me out of the habit of only looking at explicit things done by explicitly recognized governments, and at wider patterns of culture, history, and environment. It was while reading Peter Frost’s blog that I first encountered the phrase “gene-culture co-evolution,” which supplies the missing link. 

800px-National_IQ_per_country_-_estimates_by_Lynn_and_Vanhanen_2006
IQ by country

South Korea does well because 1. It’s not communist and 2. South Koreans are some of the smartest people in the world. 

I knew #1, but I could have saved myself a lot of time in the stacks if someone had just told me #2 instead of acting like SK’s economic success was a big mystery. 

The fact that every country was relatively poor before industrialization, and South Korea was particularly poor after a couple decades of warfare back and forth across the peninsula, obscures the nation’s historically high development. 

For example, the South Korean Examination system, Gwageo, was instituted in 788 (though it apparently didn’t become important until 958). Korea has had agriculture and literacy for a long time, with accompanying political and social organization. This probably has more to do with South Korea having a relatively easy time adopting the modern industrial economy than anything in particular in the governments’ plans. 

Cochran has an interesting post on his blog on Jared Diamond and Domestication: 

In fact, in my mind the real question is not why various peoples didn’t domesticate animals that we know were domesticable, but rather how anyone ever managed to domesticate the aurochs. At least twice. Imagine a longhorn on roids: they were big and aggressive, favorites in the Roman arena. … 

The idea is that at least some individual aurochs were not as hostile and fearful of humans as they ought to have been, because they were being manipulated by some parasite. … This would have made domestication a hell of a lot easier. …

The beef tape worm may not have made it through Beringia.  More generally, there were probably no parasites in the Americas that had some large mammal as intermediate host and Amerindians as the traditional definite host. 

They never mentioned parasites in gov class. 

Back to the book–I thought this was pretty interesting:

One sign of this reduced disease pressure is the unusual distribution of HLA alleles among Amerindians. the HLA system … is a group of genes that encode proteins expressed on the outer surfaces of cells. the immune system uses them to distinguish the self from non-self… their most important role is in infections disease. … 

HLA genes are among the most variable of all genes. … Because these genes are so variable, any two humans (other than identical twins) are almost certain to have a different set of them. … Natural selection therefore favors diversification of the HLA genes, and some alleles, though rare, have been persevered for a long time. In fact, some are 30 million years old, considerably older than Homo sapiens. …

But Amerindians didn’t have that diversity. Many tribes have a single HLA allele with a frequency of over 50 percent. … A careful analysis of global HLA diversity confirms continuing diversifying selection on HLA in most human populations but finds no evidence of any selection at all favoring diversity in HLA among Amerindians.

The results, of course, went very badly for the Indians–and allowed minuscule groups of Spaniards to conquer entire empires. 

The threat of European (and Asian and African) diseases wiping out native peoples continues, especially for “uncontacted” tribes. As the authors note, the Surui of Brazil numbered 800 when contacted in 1980, but only 200 in 1986, after tuberculosis had killed most of them. 

…in 1827, smallpox spared only 125 out of 1,600 Mandan Indians in what later became North Dakota.

The past is horrific. 

I find the history ancient exploration rather fascinating. Here is the frieze in Persepolis with the okapi and three Pygmies, from about 500 BC.

The authors quote Joao de Barros, a 16th century Portuguese historian: 

But it seems that for our sins, or for some inscrutable judgment of God, in all the entrances of this great Ethiopia we navigate along… He has placed a striking angel with a flaming sword of deadly fevers, who prevents us from penetrating into the interior to the springs of this garden, whence proceed these rivers of gold that flow to the sea in so many parts of our conquest.

Barros had a way with words. 

It wasn’t until quinine became widely available that Europeans had any meaningful success at conquering Africa–and even still, despite massive technological advantages, Europeans haven’t held the continent, nor have they made any significant, long-term demographic impact. 

EX-lactoseintolerance
Source: National Geographic

The book then segues into a discussion of the Indo-European expansion, which the authors suggest might have been due to the evolution of a lactase persistence gene. 

(Even though we usually refer to people as “lactose intolerance” and don’t regularly refer to people as “lactose tolerant,” it’s really tolerance that’s the oddity–most of the world’s population can’t digest lactose after childhood.

Lactase is the enzyme that breaks down lactose.)

Since the book was published, the Indo-European expansion has been traced genetically to the Yamnaya (not to be confused with the Yanomamo) people, located originally in the steppes north of the Caucasus mountains. (The Yamnaya and Kurgan cultures were, I believe, the same.) 

An interesting linguistic note: 

Uralic languages (the language family containing Finnish and Hungarian) appear to have had extensive contact with early Indo-European, and they may share a common ancestry. 

I hope these linguistic mysteries continue to be decoded. 

The authors claim that the Indo-Europeans didn’t make a huge genetic impact on Europe, practicing primarily elite dominance–but on the other hand, A Handful of Bronze-Age Men Could Have Fathered 2/3s of Europeans:

In a new study, we have added a piece to the puzzle: the Y chromosomes of the majority of European men can be traced back to just three individuals living between 3,500 and 7,300 years ago. How their lineages came to dominate Europe makes for interesting speculation. One possibility could be that their DNA rode across Europe on a wave of new culture brought by nomadic people from the Steppe known as the Yamnaya.

That’s all for now; see you next week.

A theory of male and female Sociopathy, pt 2

Note: this is just a theory, developed in reaction to recent conversations. 

As we were discussing Friday, one form of female sociopathy (at least relevant to this conversation) likely involves manipulating or coercing others into providing resources for her children.

There are a couple of obvious tropes:

  1. The evil stepmother, who shunts resources away from a man’s first child, toward his later children. 
  2. The cuckoldress, who tricks or convinces a man to care for another man’s children (this is not always seen as evil, since the male drive to provide for children is triggered at least partly by their proximity, since men cannot give birth, and thus men feel genuine affection for children who happen to be around them,)
  3. The crazy ex, who sues a man for all he is worth, doing her best to prevent him from being able to provide for any future children. 

How crazy are women? 

NSDUH_AMI-_2012_GRAPH_148270_2

22%–slightly more than 1 in 5–women have been diagnosed with a mental illness, at least according to all of the data I’ve seen. Since mental illness peaks during the childbearing ages and falls off quickly after menopause, we can also assume that this rate is closer to 1 in 4 during these years. 

(The dramatic problems our Native American communities are facing is a separate matter, deserving of its own post.)

The odd thing about this data is that mental illness rates are higher for women than men, despite the fact that mental retardation and mental disability rates are higher for men than women. Men are more likely than women to have serious conditions like non-verbal autism and schizophrenia, more likely to be homeless or commit suicide. When things go terribly wrong, the sufferers are disproportionately male (an unfortunate side effect of the Y chromosome causing greater male variability than female variability on a variety of traits.) 

So why on earth do more women than men suffer from mental illness? 

Perhaps some forms of mental illness confer some unexpected benefits on women. 

Many (perhaps most) “mental illnesses” correlate with a single personality trait–neuroticism

“Previously we thought that mental illnesses such as depression, schizophrenia, bipolar disorder, and substance abuse, were completely separate diseases,” Ystrøm says.

But research has now shown that these illnesses are often linked. If you suffer from one mental illness, you are more likely to develop another. And if someone in your immediate family has a psychiatric illness, your risk increases not only for this disorder, but for all other disorders.

These findings have led researchers to suspect that there could be a common underlying factor that increases an idividual’s risk of mental illness, overall. … 

Ystrøm and colleagues have used new statistical methods to look for patterns in personality, mental disorders, genes, and environmental factors, among the twins in the Twin Register. 

And the answer to the question the researchers asked is: yes, neuroticism seems to be the personality trait that best describes the risk of all mental disorders. …

“This one trait doesn’t explain everything. Anyone can develop a mental illness…”

And in women, neuroticism correlates with… more surviving offspring (in at least one study)

Taking an evolutionary approach, we use data from a contemporary polygynous high-fertility human population living in rural Senegal to investigate whether personality dimensions are associated with key life-history traits in humans, i.e., quantity and quality of offspring. We show that personality dimensions predict reproductive success differently in men and women in such societies and, in women, are associated with a trade-off between offspring quantity and quality. In women, neuroticism positively predicts the number of children, both between and within polygynous families. Furthermore, within the low social class, offspring quality (i.e., child nutritional status) decreases with a woman’s neuroticism, indicating a reproductive trade-off between offspring quantity and quality. 

What is neuroticism, in the Big 5 Personality Traits* sense? 

*Note: I am not endorsing or denying all five traits one way or another.

It’s worrying. Mothers who worry more about their offspring have more offspring–though it’s quite easy to imagine that the causality points in the opposite direction as the study’s authors conclude–poor women with lots of skinny babies have more reason to worry about their children than women with a few fat babies. 

When are women most likely to experience mental illness?

Immediately after the birth of a child. It’s called post-partum depression, and it can be very bad–one woman in my moms’ group ended up in the mental hospital after developing post-partum psychosis. Andrea Yates famously drowned her five children during a bout of post-partum depression/psychosis.

Why on earth would women develop a debilitating mental illness at the most vulnerable time in their offspring’s life? Wouldn’t natural selection select rather quickly against anything that makes women worse at taking care of their offspring? 

Let’s turn to everyone’s favorite genetic disease, sickle cell anemia. SCA is famous for being a relatively simple genetic mutation of the sort where if you have one copy of the sickle cell gene, you are less likely to get malaria, and if you have two copies, you tend to die. In areas where malaria is common, the cost of having a quarter of your children die from SCA is lower than the cost of loosing them to malaria. 

Personality traits, including neuroticism, generally exist on a continuum. People may become more neurotic when life warrants it, and less neurotic when they don’t need to worry. A mother with a new baby is in a very vulnerable state–she has just lost a good deal of blood, may not be able to walk, and has an infant to care for every other hour, day and night. It is not a normal state by any measure. It is a time when being extra attentive and extra aware of threats and predators is in a woman’s interest.

It is also a time when women are most in need of help from their mates, relatives, or other friends. Increased neuroticism may also prompt others to attend more closely to the new mother, helping her out. . Increased neuroticism may be so helpful during this time period that a few women getting way too much neuroticism and becoming extremely depressed or even killing their children is a cost outweighed by the increased survival of babies whose mothers had moderate levels of neuroticism. 

Let us note that nature doesn’t care about your feelings. Male praying mantises who allow themselves be eaten by their mates have more offspring than the ones who don’t, but that doesn’t mean male praying mantises enjoy getting eaten. Children who die of sickle

cell anemia don’t much appreciate that their siblings were protected from malaria, either.

An increase in neuroticism immediately after the birth of a baby may prompt a mother to take better care of it, but that doesn’t mean she enjoys the neuroticism. Neither does it mean that post-partum depression is healthy, any more than sickle cell anemia is healthy just because it’s a side effect of a trait that helps people avoid malaria. 

But wait, I have more studies!

Reproductive Fitness and Genetic Risk of Psychiatric Disorders in the General Population

The persistence of common, heritable psychiatric disorders that reduce reproductive fitness is an evolutionary paradox. Here, we investigate the selection pressures on sequence variants that predispose to schizophrenia, autism, bipolar disorder, major depression and attention deficit hyperactivity disorder (ADHD) using genomic data from 150,656 Icelanders, excluding those diagnosed with these psychiatric diseases. … Higher polygenic risk of autism is associated with fewer children and older age at first child whereas higher polygenic risk of ADHD is associated with having more children. We find no evidence for a selective advantage of a high polygenic risk of schizophrenia or bipolar disorder. Rare copy-number variants conferring moderate to high risk of psychiatric illness are associated with having fewer children and are under stronger negative selection pressure than common sequence variants. …

In summary, our results show that common sequence variants conferring risk of autism and ADHD are currently under weak selection in the general population of Iceland. However, rare CNVs that also impact cognition are under stronger selection pressure, consistent with mutation-selection balance. The hypothesis that a selective advantage accounts for the prevalence of sequence variants conferring risk of schizophrenia and bipolar disorder is unproven, but rather this empirical evidence suggests that common sequence variants largely escape selection as their individual effect sizes are weak.

Unfortunately, this study mostly looks at the data in aggregate, instead of breaking it down by males and females. (And I don’t know why they would bother excluding people who actually have the conditions they are trying to study, but perhaps it doesn’t make much difference.) 

Thankfully, they did break down the data by male/female in the tables–Table 1 and Table 2. These tables are confusing, but the takeaway is that mental illness has a bigger effect on male fertility than female fertility. 

Also: Fecundity of Patients with Schizophrenia, Autism, Bipolar Disorder, Depression, Anorexia Nervosa, or Substance Abuse vs. their Unffected Siblings

Results Except for women with depression, affected patients had significantly fewer children (FR range for those with psychiatric disorder, 0.23-0.93; P < 10−10). This reduction was consistently greater among men than women, suggesting that male fitness was particularly sensitive. Although sisters of patients with schizophrenia and bipolar disorder had increased fecundity (FR range, 1.02-1.03; P < .01), this was too small on its own to counterbalance the reduced fitness of affected patients. Brothers of patients with schizophrenia and autism showed reduced fecundity (FR range, 0.94-0.97; P < .001). Siblings of patients with depression and substance abuse had significantly increased fecundity (FR range, 1.01-1.05; P < 10−10). In the case of depression, this more than compensated for the lower fecundity of affected individuals.

Conclusions Our results suggest that strong selection exists against schizophrenia, autism, and anorexia nervosa and that these variants may be maintained by new mutations or an as-yet unknown mechanism. Bipolar disorder did not seem to be under strong negative selection. Vulnerability to depression, and perhaps substance abuse, may be preserved by balancing selection, suggesting the involvement of common genetic variants in ways that depend on other genes and on environment.

Now, this study gets interesting in its graphs: 

m_yoa120017f1
From Fecundity of Patients with Schizophrenia, Autism, Bipolar Disorder, Depression, Anorexia Nervosa, or Substance Abuse vs their Unaffected Siblings

In every case, mental illness has a bigger effect on male fertility than female–and in the case of depression, it has no effect on female fertility. 

But wait: 

m_yoa120017f2
Same source.

This graph is confusingly labeled, but it is breaking down the correlation on the brothers and sisters of people with mental disorders. So the first dot represents the brothers of people with schizophrenia; the second dot represents the sisters of people with schizophrenia. 

None of these effects are huge, and some of them changed when “comorbidities were included in the analysis,” though it’s not clear exactly what that means–the word comorbidity in this context refers to people with more than one diagnosis. 

For the objectives of this study, we first analyzed each disorder separately without accounting for comorbidities. A secondary analysis was then performed that corrected for comorbidities by analyzing all disorders simultaneously.

So when you analyze all of the disorders together, sisters of schizophrenics had no increased fertility, and neither did the siblings of people with bipolar. Depressed men had average fertility, while depressed women actually had slightly above average fertility. The results for anorexia, substance abuse, and autism didn’t change. 

And from Spain: Seven Dimensions of Personality Pathology are Under Sexual Selection in Modern Spain

Personality variation is increasingly thought to have an adaptive function. This is less clear for personality disorders (PDs)—extreme variants of personality that cause harm in most aspects of life. However, the possibility that PDs may be maintained in the population because of their advantages for fitness has been not convincingly tested. In a sample of 959 outpatients, we examined whether, and how, sexual selection acts on the seven main dimensions of personality pathology, taking into account mating success, reproductive success, and the mediating role of status. We find that, to varying extents, all personality dimensions are under sexual selection. Far from being predominantly purifying, selective forces push traits in diverging, often pathological, directions. These pressures differ moderately between the sexes. Sexual selection largely acts in males through the acquisition of wealth, and through the duration (rather than the number) of mates. This gives a reproductive advantage to males high in persistence–compulsivity. Conversely, because of the decoupling between the number of mates and offspring, the promiscuous strategy of psychopaths is not so successful. Negative emotionality, the most clinically detrimental trait, is slightly deleterious in males but is positively selected in females, which can help to preserve variation. 

It’s interesting that the invention of birth control may have inadvertently selected against promiscuous psychopaths–rather similar to the theory that abortion is responsible for the decrease in crime since the early 90s. 

“Negative emotionality” is likely equivalent to “neuroticism.”

There are two obvious reasons why mental illness might have more of an effect on males than females–one is that mental illness might simply be mores severe for males than females, on average. The second is that mental illness interferes more with holding down a job than with being a housewife, so women with mental illnesses have more options than men. 

Less obvious, though, is that some of these traits might actually be beneficial–in small quantities–for women.

That’s enough for now; let’s continue this discussion on Friday. (Wednesday is book club.)