r.i.p. blank slate (and what does “the environment” mean anyway?)

so the mother of all meta-analyses of twin studies and the heritability of human traits was published the other day: “Meta-analysis of the heritability of human traits based on fifty years of twin studies” [pdf].

the authors looked at “17,804 traits from 2,748 publications including 14,558,903 partly dependent twin pairs, virtually all published twin studies of complex traits.” 14.5+ MILLION twin pairs! as james thompson said, this study pretty much represents “the mother of ‘F*** Off’ samples.” (~_^) in future, if someone says to you that twin studies were debunked a long time ago, blah, blah, blah, just point them to this paper.

and the upshot is: we are not blank slates. we never were.

from the paper, “[A]cross all traits the reported heritability is 49%.” in other words, these researchers found that pretty much half of the variance in all sorts of physical and behavioral traits in humans — the differences that we see between people — can be accounted for by genetics.

here’s a key table from the paper. i took the liberty of jiggling it around a bit so it would fit better on the blog (h2 is what you should be looking at here — that’s narrow sense heritabilty):

twin studies meta-analysis

the press has picked this up as there being an even split between nature and nurture, genes versus “the environment.” here, for example, from the huffington post*:

“Nature Or Nurture? The Long-Running Debate May Finally Be Settled”

“It’s an age-old debate: do our genes make us who we are, or is it the environment in which we were raised?

“There’s long been agreement that both ‘nature’ and ‘nurture’ play some role in determining many aspects of our physical and mental selves, from our height and weight to our intelligence and disposition. But as to which plays the bigger role in shaping us, scientists have never seemed to agree.

“That debate may now be over, thanks to a sweeping analysis of studies conducted around the world for more than five decades. The analysis — involving more than 14.5 million twin pairs from 39 countries — indicates that nature and nurture are virtually tied.

“Across all of our traits, in other words, genes and environment exert equal influence.”

yeeeessss…but what is “the environment”? on hearing that most people will think of things like reading bedtime stories to kids or playing mozart to your unborn fetus. but those sorts of things are decidedly not what the environment is in this context. from kevin mitchell of wiring the brain:

i’ve blogged this before, but i think we all need to read it again — from steven pinker on “the environment”:

“Even the technical sense of ‘environment’ used in quantitative behavioral genetics is perversely confusing. Now, there is nothing wrong with partitioning phenotypic variance into components that correlate with genetic variation (heritability) and with variation among families (‘shared environment’). The problem comes from the so-called ‘nonshared’ or ‘unique environmental influences.’ This consists of all the variance that is attributable neither to genetic nor familiar variation. In most studies, it’s calculated as 1 – (heritability + shared environment). Practically, you can think of it as the differences between identical twins who grow up in the same home. They share their genes, parents, older and younger siblings, home, school, peers, and neighborhood. So what could make them different? Under the assumption that behavior is a product of genes plus environment, it must be something in the environment of one that is not in the environment of the other.

But this category really should be called ‘miscellaneous/unknown,’ because it has nothing necessarily to do with any measurable aspect of the environment, such as one sibling getting the top bunk bed and the other the bottom, or a parent unpredictably favoring one child, or one sibling getting chased by a dog, coming down with a virus, or being favored by a teacher. These influences are purely conjectural, and studies looking for them have failed to find them. The alternative is that this component actually consists of the effects of chance – new mutations, quirky prenatal effects, noise in brain development, and events in life with unpredictable effects.

“Stochastic effects in development are increasingly being recognized by epidemiologists, frustrated by such recalcitrant phenomena such as nonagenarian pack-a-day smokers and identical twins discordant for schizophrenia, homosexuality, and disease outcomes. They are increasingly forced to acknowledge that God plays dice with our traits. Developmental biologists have come to similar conclusions. The bad habit of assuming that anything not classically genetic must be ‘environmental’ has blinkered behavioral geneticists (and those who interpret their findings) into the fool’s errand of looking for environmental effects for what may be randomness in developmental processes.”

and more from kevin mitchell:

“Just because some trait is not genetic does not mean it is not innate. If we are talking about how the brain gets wired, any number of prenatal environmental factors are known to have large effects. More interestingly, however, and probably a greater source of variance across the population, is intrinsic developmental variation. Wiring the brain is a highly complex procedure, reliant on cellular processes that are, in engineering terms, inherently ‘noisy’. Running the programme from the same starting point (a specific genotype) does not generate exactly the same output (the phenotype) every time. The effects of this noise are readily apparent at the anatomical level, when examining the impact of specific mutations, for example. In many cases, the phenotypic consequences are quite variable between genetically identical organisms, or even on two sides of the same brain. (If you want to see direct evidence of such developmental variation, take a directly face-on photograph of yourself, cut it in half and make mirror-image copies of the left and right sides. You will be amazed how different the two resultant faces are).

If the way the brain is wired is determined, not just by the starting genotype, but, to a large extent by chance events during development, then it is reasonable to expect this variation to be manifest in many psychological traits. Such traits may thus be far more innate than behavioural genetics studies alone would suggest.

in other words, it’s NOT genes + environment (or nature + nurture) — not as most people would think of it anyway. it’s genes + shared environment (which, since it’s shared, i.e. the same for the individuals in question, oughtn’t to make a difference, right?) + nonshared environment (which can include de novo mutations and development noise, which also may be heritable! iow, variation itself might be a genetic trait.). not much room for the effects of nurture here.

so, when you see a figure like 51% for “environmental” causes behind the differences we see in traits between people, remember that that very much includes biological causes like new mutations that are particular to individuals and developmental “noise,” which again may ultimately be regulated by genes.

(and, no, it’s not epigenetics either! see here and here and here.)

h/t once again to jayman for cluing me in on this in the first place! (^_^)
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*to give credit where credit is due, the huff post journalist did mention that part of what’s included in “the environment” is measurement error. that is correct. edit: see comment below about measurement error. so the 49% heritabilty figure should be considered a very conservative figure.

p.s. – there’s even a dedicated website where you can have a look at all the heritability numbers for yourself. enjoy!

see also: Gone with the Wind from dr. james thompson, Nature, nurture and noise from kevin mitchell, and About Developmental Noise and Environmental Hereditarianism from jayman.

previously: it’s not nature and nurture…

(note: comments do not require an email. the blank slate.)

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linkfest – 05/11/15

Deep-ocean microbe is closest living relative of complex cells“A new study indicates that plants, fungi, and animals are descendants of archaea, the group of single-celled organisms that includes Sulfolobus, a resident of hot springs.” – h/t bill barendse! – see also: New Loki Microbe Is Closest Relative To All Complex Life.

A Surprise for Evolution in Giant Tree of Life“Researchers build the world’s largest evolutionary tree and conclude that species arise because of chance mutations — not natural selection…. This controversial proposal stems from efforts by Hedges and collaborators to build the world’s most comprehensive tree of life — a chart plotting the connections among 50,000 species of Earth’s vast menagerie. Their analysis suggests that speciation is essentially random. No matter what the life form — plant or animal, insect or mammal — it takes about 2 million years for a new species to form. Random genetic events, not natural selection, play the main role in speciation.” – see also Was Charles Darwin Wrong About Speciation? from razib.

Genetic changes to basic developmental processes evolve more frequently than thought“Newly evolved genes can rapidly assume control over fundamental functions during early embryonic development. The findings suggest that evolutionary changes to the genetics of fundamental biological processes occur more frequently than previously thought.” – h/t david bachinsky!

The First GMO Is 8,000 Years Old“Scientists find that bacteria modified DNA in sweet potatoes millennia ago.”

Behavioral idiosyncrasy reveals genetic control of phenotypic variability [pdf] – “If we could rear genetically identical individuals from a variety of genetic backgrounds and rear them in the same environment, how much phenotypic variation between individuals of the same genotype would we see? Would different genetic backgrounds differ in their degree of variability? What would account for these differences? We used Drosophila inbred lines to address these questions focusing on variability in locomotor handedness. We show that different genotypes vary dramatically in their propensity for variability, that phenotypic variability itself, as a trait, can be heritable, and that loci affecting variability can be mapped. The genetic control of variability has received little attention in quantitative genetics despite the important role variability plays in explaining phenotypic variation between individuals.”

two tweets from the Biology of Genomes meeting re. a presentation on mutation rates:

Team Characterizing DNA from Ancient Human with Recent Neanderthal Ancestry [registration req.] – see also Ancient DNA from an Upper Paleolithic European with recent Neanderthal ancestry“the male sample, Oase 1, is 37-42K years old and comes from the Pestera cu Oase site in southwestern Romania. it’s estimated to harbor 5-11% of genome-wide Neanderthal ancestry, with as much as 50% on chromosome 12. the admixture is in relatively long stretches, which suggests that the mixture took place four to six generations before Oase 1 was alive. – @the eurogenes blog.

The archaeology, chronology and stratigraphy of Madjedbebe (Malakunanja II): A site in northern Australia with early occupation“The stone artefacts and stratigraphic details support previous claims for human occupation 50–60 ka and show that human occupation during this time differed from later periods.” – h/t chris stringer!

Stone bracelet is oldest ever found in the world“Dating back 40,000 years to the Denisovan species of early humans, new pictures show beauty and craftsmanship of prehistoric jewellery.” – denisovan jewelry!!

The Old Race – from greg cochran.

Ancient DNA Tells a New Human Story“The study of ancient DNA has challenged this view. We now know that mass migrations occurred repeatedly, overwhelming natives while absorbing some of their genes…. Joseph Pickrell of Columbia University and David Reich of Harvard University argue that ‘major upheavals’ of human population have been ‘overwriting’ the genetic history of the past 50,000 years. The result, they say, is that ‘present-day inhabitants of many places in the world are rarely related in a simple manner to the more ancient peoples of the same region.'” – from matt ridley.

2,500-year old Etruscans“All that can be said based on this is that they seem broadly southern European and not particularly Tuscan.” – from dienekes. – h/t anthropology tip!

The time and place of European gene flow into Ashkenazi Jews – @the eurogenes blog.

Symbolic bones and interethnic violence in a frontier zone, northwest Mexico, ca. 500–900 C.E.“Persistent interethnic violence has affected some global regions for centuries…. In the prehispanic Northern Frontier of Mesoamerica, approximately 500–900 C.E., people of different ethnic backgrounds struggled for standing in a shifting sociopolitical landscape. Evidence is consistent with long-term social violence….” – h/t gaetan burgio!

London Conference on Intelligence 2015 Keynote – from dr. james thompson.

NIH bans funding for genetic engineering of human embryos – (>.<)

Three hundred years of low non-paternity in a human population“Here we use this approach to investigate 1273 conceptions over a period of 330 years in 23 families of the Afrikaner population in South Africa. We use haplotype frequency and diversity and coalescent simulations to show that the male population did not undergo a severe bottleneck and that paternity exclusion rates are high for this population. The rate of cuckoldry in this Western population was 0.9% (95% confidence interval 0.4–1.5%), and we argue that given the current data on historical populations we have to conclude that, at least for Western human populations, cuckoldry rate is probably in the range of 1%.” – h/t debbie kennett!

Genius and autism may share genetic link, study finds“Child prodigies and their autistic family members may share a genetic link, according to findings published online for the April issue of Human Heredity.”

Immediate susceptibility to visual illusions after sight onset – h/t laura kelley!

The glass is half full *and* half empty: A population-representative twin study testing if optimism and pessimism are distinct systems“Here, we addressed these questions in a genetically informative sample of 852 pairs of twins. Distinct genetic influences on optimism and pessimism were found. Significant family-level environment effects also emerged, accounting for much of the negative relationship between optimism and pessimism, as well as a link to neuroticism. A general positive genetics factor exerted significant links among both personality and life-orientation traits. Both optimism bias and pessimism also showed genetic variance distinct from all effects of personality and from each other.” – h/t stuart ritchie!

Stanford researchers observe the moment when a mind is changed

Nature or nurture? Are sporting champions born to win? – h/t razib!

Menstrual Cycle Phase Does Not Predict Political Conservatism

Heritability of decisions and outcomes of public goods games

The kind of student you were in elementary school predicts mortality – h/t timothy bates!

The Mask of Sanity Revisited: Psychopathic Traits and Affective Mimicry – h/t claire lehmann! who tweeted: “People with psychopathy can produce highly convincing but fake expressions of feelings.”

Polygyny without wealth: popularity in gift games predicts polygyny in BaYaka Pygmies – h/t steve stewart williams!

The kin selection argument continues, with those denying its importance holding firm. They’re wrong. – from jerry coyne.

Behaviorism and the revival of antiracism – from peter frost.

Heterogeneity of long-history migration explains cultural differences in reports of emotional expressivity and the functions of smiles – hmmmm. really? – see also: What your smile says about where you’re from“If you come from a country of immigrants, you’re more likely to crack a friendly smile on the street. That’s the conclusion of a new study, which may explain why Americans beam more than their Chinese and Russian counterparts.”

Is reading to your kids “unfairly disadvantaging” others? – hahahahahaha! – h/t brian boutwell! who tweeted: “The nonsense that you can believe when you’re convinced that genes don’t matter.” – see also Is having a loving family an unfair advantage?

How uncommon is tickertaping? Prevalence and characteristics of seeing the words you hear – h/t kevin mitchell!

Peter Visscher: Genomics, Big Data, Medicine, and Complex Traits – @steve hsu’s.

Memes are Genes – from evolution theorist. (where do memes come from?) – h/t jayman!

How can our future Mars colonies be free of sexism and racism? – (>.<) #virtuesignalling – h/t ed west!

Paternity Case for a New Jersey Mother of Twins Bears Unexpected Results: Two Fathers – ruh roh!

After Nearly Claiming His Life, Ebola Lurked in a Doctor’s Eye“Before he contracted Ebola, Dr. Ian Crozier had two blue eyes. After he was told he was cured of the disease, his left eye turned green [temporarily].” – whoa.

How music evolves“Statistical analysis of music reveals the truth about its periods of revolution.” – h/t argumatronic!

The Medieval Roots of Our DIY Gun Culture“Forget 3-D printers. The first garage gunsmiths date back to the late Middle Ages.”

When Baltimore Shook With Anger, Here’s What China Saw“Online reaction revealed much about Chinese tension with an influx of African immigrants.” – h/t holtz!

No, there’s no “hate speech” exception to the First Amendment – duh. – from eugene volokh.

bonus: The migration of the eagle hunters – awesome!

(note: comments do not require an email. kazakh eagle hunter!)

top ten list 2014

here’s a top ten-ish selection of my posts from this year, selected by me (this blog is not a democracy! (~_^) ). they weren’t necessarily the most read or most commented upon posts, but just the ones that i like the best and that i’d like people to read. ymmv!

a BIG thanks to all of you who do read the ol’ blog! and many, many thanks for all the informative and insightful comments. (^_^) …and for some of the crazy comments, too. (~_^)

big summary post on the hajnal line“so, apart from indicating patterns of nuptuality in late medieval and modern europe, hajnal’s line also represents the extent of both manorialism and The Outbreeding Project on the continent. both of these together set up a very new and different sort of social environment for western europeans — a new, and quite unique, social environment which exerted some very different sorts of selection pressures on the populations, particularly on social behaviors, but perhaps on other traits as well.”

medieval manorialism’s selection pressures“medieval society in northern europe (ca. 400-1500 a.d.) produced some quite unique selection pressures which very much shaped the characteristics and personalities of ‘core’ europeans….”

die ostsiedlung“from a sociobiological point-of-view, probably the most underappreciated event in recent western european history. that and the reconquest of spain.”

mating patterns of the medieval franks“by the 800s, second cousin marriages amongst the franks were considered ‘scandalous.’ bishops actively enforced the bans in their dioceses and neighbors willingly squealed on their cousin-marrying neighbors to the bishops. by the 800s-1000s, there is good evidence that both the frankish aristocracy and the lower classes avoided close cousin marriage.” — see also: kindreds, communes, feuds, and mating patterns in medieval france“beginning in the 1000s, there are indications — the rise of lineages and the appearance of communes — that the french kindreds were starting to break apart. however, feuding continued in france into the 1200-1300s, so clannishness did not disappear in france overnight.”

the transition from shame to guilt in anglo-saxon england (and “core” europe)“feelings of guilt were probably selected for over the course of the middle ages in northwestern europe starting in the early part of the period.” — see also: more on the origins of guilt in northwestern european populations“the center of the guilt culture in northwestern europe — the core region which (historically anyway) has been characterized by the least corruption, the highest levels of trust, liberal democracy, free societies, low levels of internal violence, high levels of human accomplishment, the invention of capitalism, the advancement of science, the development of the ideas and ideals of the enlightenment, and pretty much everything else we call western civilization today — is the core where The Outbreeding Project began the earliest in europe.”

sneak preview: violence, punishment, outbreeding, and swashbuckling pirates in medieval england“over the course anglo-saxon period…the death penalty did come to be more widely applied to cases of homicide, but for most of the period there weren’t really very many executions of killers…. more laws demanding the death penalty (or castration) for killings were issued and enforced during the anglo-norman and angevin periods… [but] executions actually remained comparatively low during large parts of the norman period…. as far as i can tell, criminals were executed right and left during the tudor period. the use of capital punishment really ramped up during the 1500s.” — see also: homicide rates in various regions of thirteenth century england“[I]t is possible that every person in England in the thirteenth century, if he did not personally witness a murder, knew or knew of someone who had been killed.”

a study in swiss“my guess is that the swiss are some of western europe’s ‘inbetweeners’ as far as outbreeding goes. i guessed that they probably got involved in The Outbreeding Project later than some other western europeans — the ones in and closer to the center of my ‘core’ europe. and they didn’t experience manorialism either (unless some of them on the swiss plateau did?).”

reverse renaissance?“perhaps the arabized world underwent a *reverse* renaissance process thanks to the introduction by the arabs of the most inbred form of cousin marriage — father’s brother’s daughter (fbd) marriage — to the populations of the middle east/maghreb….” — see also asabiyyah and asabiyyah ii – clannishness and the abbasid caliphate.

fbd cousin marriage and clans and tribes in iraq“i think a long term inbreeding society selects — or *can* select — for what i call clannishness. and iraqis have got that in spades. they’ve got clans and tribes, nepotism, and an obvious inability to handle liberal democracy. not that that’s some sort of goal in and of itself. i’m just sayin’.”

cousin marriage in sub-saharan africa“there is also a wide variety of mating patterns in ss africa. some populations avoid cousin marriage altogether. we’ve already seen this with the bamileke of cameroon and the igbo of nigeria. also the turkana of kenya and quite possibly the amhara of ethiopia (not 100% sure about them — need to double-check). a notable group which apparently avoids cousin marriage is the zulu. but plenty of other ss africa groups do practice cousin marriage like, as you’ll see in the table below, the kongo and luba in the democratic republic of congo, the ashanti in ghana, the sotho-tswana in south africa, and the kpelle of liberia.” — see also: the bamileke of cameroon and fulani, hausa, igbo, and yoruba mating patterns.

the american revolutions“that there were four american revolutions is a result of the fact that four (five?) somewhat different english populations settled in different regions of north america. the cultural and attitudinal differences between these regions persist to this day because, undoubtedly, there are genetic variations between the populations — probably average genetic differences in the frequencies of genes related to behaviors, personality, and even intelligence. these regional differences also persist because, since the very founding of the united states, like-minded people have been self-sorting themselves within the country so that they group together — and that sorting process has *not* been slowing down.”

it’s not nature and nurture…“…it’s nature and…*we dunno*…miscellaneous/unknown/noise?” — this post's actually very important. READ THIS POST! think about it for a while and let it sink in. and make sure to follow the links!

– my "what is hbd" series: what is human biodiversity (hbd)?“human biodiversity (hbd) is very simply the diversity found among and between human populations that has a biological basis.” — see also: what human biodiversity (hbd) is not; examples of human biodiversity (hbd); why human biodiversity (hbd) is true; hbd and racism; and hbd and politics.

– and finally: you and me and hbd“if you accept that humans exhibit biologically based diversity, then you’d better be prepared to accept ALL of it.”

previously: top ten list 2013

tweets of the week – 12/01/14

two weeks, actually…

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https://twitter.com/razibkhan/status/534487173429358592

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https://twitter.com/MaxCRoser/status/538038846563565569

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https://twitter.com/clairlemon/status/538918495388311552

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linkfest – 11/16/14

look! a linkfest! (^_^)

Bayesian analyses of Yemeni mitochondrial genomes suggest multiple migration events with Africa and Western Eurasia

37,000-year-old Russian skeleton has Neanderthal DNA that’s gone missing“Sequences present in its genome haven’t been found in modern human populations.” – see also Remix from greg cochran. – see also Genome of Kostenki-14, an Upper Paleolithic European (Seguin-Orlando, Korneliussen, Sikora, et al. 2014) from dienekes.

Humans Would Beat Neanderthals in Marathon

Different Ways to Color a Cat – from razib. – h/t billare! who tweeted: “Progenitors of modern Europeans were fairly light-skinned–why did a 2nd bout of selection leave its tell-tale marks?”

Admixture in the Americas: Introduction, partial correlations and IQ predictions based on ancestry – from emil kirkegaard.

Our Futile Efforts to Boost Children’s IQ“How can parenting and socioeconomic status play such minor roles in determining IQ, when scholars on all sides of the nature-nurture debate agree that somewhere around half of the variation in IQ is environmental? The short answer is that the environment that affects IQ doesn’t consist of the advantages that most people have in mind — parents who talk a lot to their toddlers, many books in in the house for the older children, high-quality schools and the like. Instead, studies over the past two decades have consistently found that an amorphous thing called the “nonshared” environment accounts for most (in many studies, nearly all) of the environmentally grounded variation. Scholars are still trying to figure out what features of the nonshared environment are important. Peers? Events in the womb? Accidents? We can be sure only of this: The nonshared environment does not lend itself to policy interventions intended to affect education, parenting, income or family structure.” – from charles murray. – h/t mr. mangan, esq!

Results of a “GWAS Plus:” General Cognitive Ability Is Substantially Heritable and Massively Polygenic – h/t emil kirkegaard!

Does neural crest development drive domestication syndrome?“Altered neural crest development could be the reason mammals change in oddly consistent ways during domestication. As first noted by Darwin more than 140 years ago, domestic mammals tend to share certain characteristics—a suite of traits called the domestication syndrome.”

‘Darwin’s Dilemma’ May Be Solved“Scientists following two different lines of evidence have just published research that may help resolve ‘Darwin’s dilemma,’ a mystery that plagued the father of evolution until his death more than a century ago. Biologists and geologists have been puzzled for decades over why life began so early on this planet, and then took so long to get interesting.”

A new study pieces together the puzzle of insect evolution“A new study of insect evolution — the largest of its kind ever undertaken — has uncovered some surprising new information, confirmed some long-held hypotheses and may lead researchers toward a more comprehensive understanding of evolution. One hundred scientists from 10 countries worked together to examine 144 insect species. Their goal was to create an insect ‘family tree’ and establish a timeline of insect evolution. Their results were published recently in the journal Science.” – cool!

More evidence that certain versions of some genes can encourage violence

Facial structure predicts goals, fouls among World Cup soccer players“The scientists studied the facial-width-to-height ratio (FHWR) of about 1,000 players from 32 countries who competed in the 2010 World Cup. The results, published in the journal Adaptive Human Behavior and Physiology, showed that midfielders, who play both offense and defense, and forwards, who lead the offense, with higher FWHRs were more likely to commit fouls. Forwards with higher FWHRs also were more likely to score goals or make assists.”

Mental health: Depression needs large human-genetics studies“To understand the molecular mechanisms of depression, collect genetic data from more than 100,000 people, says Steven Hyman.”

Geneticists tap human knockouts“On average, every person carries mutations that inactivate at least one copy of 200 or so genes and both copies of around 20 genes.”

The Inexorable Progress of Science: Archaeology“With a very limited set of clues, smart guys managed to get key facts about European prehistory roughly correct almost 90 years ago . With tremendously better tools, better methods, vastly more money, more data, etc, archaeologists (most of them) drifted farther and farther from the truth.” – from greg cochran.

How Your Facebook Updates Reveal Your Personality“Extroverts tend to use words like love, tonight, party, excited and amazing. Several length variants of the word soooo and ‘text speak’ terms like lovin and ur, are more often found on extroverts’ updates. In general the extrovert word cloud is sloppy enough to make any ‘Grammar Nazi’ red in the face. When we come to introverts, use of the word computer was one of the biggest giveaways. Posting status updates about Internet, and to a lesser extent anime, doctor who, and books, were also predictive of introversion.” – from neuroskeptic.

The contribution of additive genetic variation to personality variation: heritability of personality“[W]e found that approximately 52% of animal personality variation was attributable to additive genetic variation.”

The genetics of impulsivity: evidence for the heritability of delay discounting – h/t ben southwood! who tweeted: “Impulsivity is 55% heritable at age 18.”

We are not equally empathic – from peter frost.

He’s Definitely a Liberal—Just Check Out His Brain Scan“[W]e’ve had solid indications for a while now that our ideological biases are based, in large part, on the biology of our brains…. Of course, we’d like to think we came to our core beliefs through a process of rational reflection and discussion — or, at the very least, as a psychological reaction to the influence of our parents and peers…. But the profound influence of basic brain biology has just been re-affirmed in a new research paper, which found liberals and conservatives can be easily identified through fMRI scans…. ‘Remarkably,’ writes a team led by P. Read Montague of the Virginia Tech Carilion Research Institute, ‘brain responses to a single disgusting stimulus were sufficient to make accurate predictions about an individual subject’s political ideology.'”

The Most Heritable Gut Bacterium is… Wait, What is That?“By studying 416 pairs of British twins, Julia Goodrich and colleagues from Cornell University have identified the gut microbes whose presence is most strongly affected by our genes.”

Microbiome science threatened by contamination“Non-sterile sequencing returns rogue results in dilute microbe samples.”

Global IQ and health – from dr. james thompson.

Book Review: The Ten Thousand Year Explosion (2009) by Greg Cochran and Henry Harpending – from staffan.

The ecology of religious beliefs“Both comparative and experimental evidence indicate that beliefs in moralizing high gods promote cooperation among humans, a behavioral attribute known to correlate with environmental harshness in nonhuman animals. Here we combine fine-grained bioclimatic data with the latest statistical tools from ecology and the social sciences to evaluate the potential effects of environmental forces, language history, and culture on the global distribution of belief in moralizing high gods (n = 583 societies). After simultaneously accounting for potential nonindependence among societies because of shared ancestry and cultural diffusion, we find that these beliefs are more prevalent among societies that inhabit poorer environments and are more prone to ecological duress.”

Edvard Westermarck on Morality: The Light Before the Darkness Fell and Post-Darwinian, “Evolutional” Theories of Morality in the 19th Century – from helian.

Genes contribute to behavior differences between fierce and friendly rats“Genes active in the brain implicated in differences in rats selected for aggression or tameness”

Intimidating chimpanzee males are more likely to become fathers – ruh roh. – h/t steve stewart williams!

Marriage Records Reveal Patterns of Korean Migration Through the Centuries

What Edward Luttwak Doesn’t Know About Ancient China (Or a Short History of Han-Xiongnu Relations), pt. 1 and What Edward Luttwak Doesn’t Know About Ancient China (Or a Short History of Han-Xiongnu Relations), pt. 2 – from t.greer.

There’s Something About Teutonics – from those who can see.

An extremely low-density human population exterminated New Zealand moa“Here we show that the Polynesian population of New Zealand would not have exceeded 2,000 individuals before extinction of moa populations in the habitable areas of the eastern South Island. During a brief (<150 years) period and at population densities that never exceeded ~0.01 km(-2), Polynesians exterminated viable populations of moa by hunting and removal of habitat. High human population densities are not required in models of megafaunal extinction."

A Gene by Any Other Name“What is the logic in naming human genes?”

bonus: Keeping Mates Close and Competition Out in an Ocean Sponge

bonus bonus: Here’s Why Other People’s Farts Smell Way Worse Than Your Own – we cover *all* aspects of human biodiversity here on the hbd chick blog! (~_^)

(note: comments do not require an email. an ocean sponge.)

linkfest – 03/05/14

DNA USA*“[A]bout about 4 percent of whites have at least 1 percent or more African ancestry. Although it is a relatively small percentage, the percentage indicates that an individual with at least 1 percent African ancestry had an African ancestor within the last six generations, or in the last 200 years. This data also suggests that individuals with mixed parentage at some point were absorbed into the white population. Looking a little more deeply into the data, Kasia also found that the percentage of whites with hidden African ancestry differed significantly from state-to-state. Southern states with the highest African American populations, tended to have the highest percentages of hidden African ancestry…. Previous published studies estimate that on average African Americans had about 82 percent African ancestry and about 18 percent European ancestry. But in self-identified African Americans in 23andMe’s database, Kasia found the average amount of African ancestry was closer to 73 percent. Kasia found significant differences in state-to-state comparisons. African Americans in the northern and western states have more mixed ancestry than those in the southern states…. On average Latinos had about 70 percent European ancestry, 14 percent Native American ancestry and 6 percent African ancestry. The remaining ancestry is difficult to assign because the DNA is either shared by a number of different populations around the world, or because it’s from understudied populations, such as Native Americans.” – from 23andMe.

Common Variants in the CDH7 Gene are Associated with Major Depressive Disorder in the Han Chinese Population“Recent genome-wide association study also demonstrated that CDH7 was significant associated with bipolar disorder…. Our results support CDH7 to be a risk factor of MDD in the Han Chinese population. However, further studies with more markers and independent samples were suggested to validate our findings.”

Humans May Have Been Stuck on Bering Strait for 10,000 Years“In the new Perspectives article, published today (Feb. 27) in the journal Science, the researchers compile existing data to support the idea, known as the Beringia standstill hypothesis. Among that evidence is genetic data showing that founding populations of Native Americans diverged from their Asian ancestors more than 25,000 years ago. In addition, land in the region of the Bering Strait teemed with grasses to support big game (for food) and woody shrubs to burn in the cold climate, supporting a hard-scrabble existence for ancient people.” – razib is skeptical.

Was skin cancer a selective force for black pigmentation in early hominin evolution?“[D]ata on age-associated cancer incidence and lethality in albinos living at low latitudes in both Africa and Central America support the contention that skin cancer could have provided a potent selective force for the emergence of black skin in early hominins.”

Neanderthal Introgression at Chromosome 3p21.31 Was Under Positive Natural Selection in East Asians“Studies of the Neanderthal and Denisovan genomes demonstrate archaic hominin introgression in Eurasians. Here, we present evidence of Neanderthal introgression within the chromosome 3p21.31 region, occurring with a high frequency in East Asians (ranging from 49.4% to 66.5%) and at a low frequency in Europeans. We also detected a signal of strong positive selection in this region only in East Asians…. [S]uggestive evidence supports latitude-dependent selection, implicating a role of ultraviolet-B.”

Neanderthals challenge the origins of speech“Neanderthals, may well have spoken in languages not dissimilar to the ones we use today…. [I]n terms of mechanical behaviour, the Neanderthal hyoid was basically indistinguishable from our own, strongly suggesting that this key part of the vocal tract was used in the same way. ‘From this research, we can conclude that it’s likely that the origins of speech and language are far, far older than once thought.'” – h/t billare (who is 0.1% neanderthal)!

READ THIS (yes, there *will* be a pop quiz on the material later in the week (~_^) )!: Environmental Hereditarianism“[T]here is little evidence linking most ‘measurable’ aspects of the environment to human physical or behavioral traits…. Most of the solid evidence we do have for environmental impacts come in the forms of things that do physical damage (e.g., maiming limbs or traumatic brain injury) – a category which includes poisons; or are developmental deficits, such as malnutrition. Much of the rest of it (take your pick) is lacking.” – from jayman. – previously: it’s not nature and nurture….

Outliers – from greg cochran.

New evidence confirms link between IQ, brain cortex“Rate of change in the thickness of the brain’s cortex is an important factor associated with a person’s change in IQ, according to a collaborative study by scientists in five countries…. This study is the first to show the association between cortical thickness and development in full scale IQ, and has potentially wide-ranging implications for the pedagogical world and for judicial cases in which the defendant’s IQ score could play a role in determining the severity of the sentence.”

The Germ Theory of Democracy, Dictatorship, and All Your Most Cherished Beliefs“What kind of government do you live under? Who are your sexual partners? How do you treat strangers? All of these questions may mask a more fundamental one: What germs are you warding off?” – h/t jason collins! – but see this previous post: pathogens and consanguinity“the BIG outliers, though, are the arabs and all their middle eastern/north african/south asian muslim buddies. they are the ones throwing off the correlation completely…. these societies are amongst those that have the highest consanguinity rates, and yet some of their pathogen index scores are *very* low.” that part of the world also does not do well when it comes to (liberal) democracy. – see also jayman’s response.

Nicholas Wade Takes on the Regime – jared taylor reviews nicholas wade’s upcoming book on race. – h/t hbd bibliography! – see also this comment from jayman. – and see also Harmful, toxic equalism from the awesome epigone.

The Nature of Race – from karl boetel and john furest. see also here.

12,000 year old prehistoric art shows woman hunting – maybe. kinda/sorta. (not really.) – from adam benton.

Altruism and the Dark Side of Agreeableness“[B]eware of really nice people. If they seem too good to be true, they usually are.” – from staffan.

Forgotten fathers: paternal influences on mammalian sex allocation“A growing body of evidence suggests that the assumption that males produce an unbiased proportion of X- and Y-chromosome-bearing spermatozoa is not always valid with significant between- and even within-individual variation.” – a mechanism for trivers-willard? – h/t lars penke!

Digit Span: the modest little bombshell and What does IQ 70 mean for black and white kids? – from dr. thompson.

The paradox of the Visual Word Form Area“The VWFA functions differently in different human populations. The difference is striking between people who use alphabetical script, where each symbol represents a sound, and those who use logographic script, where each symbol represents an idea. Chinese subjects process their idea-based symbols with assistance from other brain regions, whereas Westerners process their sound-based symbols only in the VWFA.” – from peter frost.

The man who destroyed America’s ego“How a rebel psychologist challenged one of the 20th century’s biggest—and most dangerous—ideas…. Among the most egregious errors they discovered were those in the papers that focused on academic performance. A correlation had been repeatedly found between high self-esteem and good grades. So, the logic went, if you boosted self-esteem you’d also boost grades. But the authors had made one of the most elementary mistakes in science. ‘When they tracked people over time,’ says Baumeister, ‘the grades came first, and then the self-esteem. High self-esteem was a *result* of good grades, not a cause.'” – h/t matthew wygant!

Genetic Influences on Political Ideologies: Twin Analyses of 19 Measures of Political Ideologies from Five Democracies and Genome-Wide Findings from Three Populations“Here we present results from original analyses of a combined sample of over 12,000 twins pairs, ascertained from nine different studies conducted in five democracies, sampled over the course of four decades. We provide evidence that genetic factors play a role in the formation of political ideology, regardless of how ideology is measured, the era, or the population sampled…. We then present results from one of the first genome-wide association studies on political ideology using data from three samples: a 1990 Australian sample involving 6,894 individuals from 3,516 families; a 2008 Australian sample of 1,160 related individuals from 635 families and a 2010 Swedish sample involving 3,334 individuals from 2,607 families. No polymorphisms reached genome-wide significance in the meta-analysis. The combined evidence suggests that political ideology constitutes a fundamental aspect of one’s genetically informed psychological disposition, but as Fisher proposed long ago, genetic influences on complex traits will be composed of thousands of markers of very small effects and it will require extremely large samples to have enough power in order to identify specific polymorphisms related to complex social traits.”

Why Americans Are So Polarized: Education and Evolution“Improvements in learning — which correlates with stronger partisanship — and the tendency to choose likeminded mates may be helping to create divided politics.” – from avi tuschman. – h/t eddy elmer!

Conservatives generally more willing to take business risks, study finds

Paternal Age at Childbearing and Offspring Psychiatric and Academic Morbidity“In the study population, advancing paternal age was associated with increased risk of some psychiatric disorders (eg, autism, psychosis, and bipolar disorders) but decreased risk of the other indexes of morbidity.”

A Genotype-First Approach to Defining the Subtypes of a Complex Disease – h/t kevin mitchell who tweeted: “Increasing recog’n that ‘common disorders; like autism really umbrella terms for many rare diseases.”

Researchers look at boy-girl differences in autism“Boys, it seems, can develop autism from a relatively small genetic hit, according to a study published today in the American Journal of Human Genetics. It takes more of a genetic wallop, though, to cause autism in girls – so when they do get it, they’re worse off. The same explanation holds true, researchers think, for the gender imbalance in ADHD (attention-deficit hyperactivity disorder), intellectual disabilities and schizophrenia.” – see also: A Higher Mutational Burden in Females Supports a “Female Protective Model” in Neurodevelopmental Disorders.

China Cracks Down on DNA Testing – h/t jayman!

Epigenetics: The sins of the father – big story in nature today. – “The roots of inheritance may extend beyond the genome, but the mechanisms remain a puzzle.” – but swedish scientist on twitter says: “But Rando misquotes Swedish human data in his Cell paper on mice. Caution for epigenetic hype!” – hmmmm. =/

The Consequences of Natural Morality“Good and Evil are not objective things. They exist as subjective impressions, creating a powerful illusion that they are objective things. This illusion that Good and Evil are objects independent of the conscious minds that imagine them exists for a good reason. It ‘works.’ In other words, its existence has enhanced the probability that the genes responsible for its existence will survive and reproduce.” – from helian.

Digit ratio predicts eminence of Polish actors – this one’s for sisyphean! (^_^) – h/t ben southwood!

Sex differences in color preferences transcend extreme differences in culture and ecology.

In Academia, Women Collaborate Less With Their Same-Sex Juniors“‘Some older women treated us younger women almost worse than some men did,’ she says. ‘We called it the “Queen Bee syndrome.”‘” – heh. – h/t claire lehmann!

Women Can Keep the Vote: No Evidence That Hormonal Changes During the Menstrual Cycle Impact Political and Religious Beliefs – behind paywall.

Women ‘subconsciously outdo other females’ during ovulation“But what the researchers found really surprising is that ovulating women did not appear to want a higher standing over men – they became kinder to them. When playing the dictator game, non-ovulating women shared 45% of their money with men, while ovulating women were willing to share 60% of their money with men. These findings are unlike anything we have ever seen in the dictator game. You just don’t see people giving away more than half of their money,’ says Prof. Durante.” – (~_^)

Women Outperform Men in Ultra-Distance Swimming – The ‘Manhattan Island Marathon Swim’ From 1983 to 2013. – because we float better (because we have that extra layer of fat)? (~_^)

Sameness and the self: philosophical and psychological considerations.“[H]ow can a person maintain a belief in the sameness of self over time in the face of continual psychological and physical change?” – h/t neuroskeptic!

Young Children Can Be Taught Basic Natural Selection Using a Picture-Storybook Intervention – but not politically correct people, apparently. (~_^) – h/t stuart ritchie!

Study: Racial bias in pain perception appears among children as young as 7 – see also: Psychologists use baby-cam to study infants’ exposure to faces.

Mixed-race children ‘are being failed’ in treatment of mental health problems“Children of mixed race are at greater risk of suffering from mental health problems and are not getting the support they need, says a report.” – in the u.k.

Inferring Character From Faces: A Developmental Study.“This research suggests that the predisposition to judge others using scant facial information appears in adultlike forms early in childhood and does not require prolonged social experience.”

Los europeos no inventaron la desigualdad en Hispanoamérica – from eduardo zugasti.

Native American city on the Mississippi was America’s first ‘melting pot’carcosa cahokia. – “By analyzing the teeth of those buried in different locations in Cahokia, Emerson, state archaeological survey bioarchaeologist Kristin Hedman and graduate student Philip Slater discovered that immigrants formed one-third of the population of the city throughout its history (from about AD 1050 through the early 1300s).”

Two-hundred-year drought doomed Indus Valley Civilization“Monsoon hiatus that began 4,200 years ago parallels dry spell that led civilizations to collapse in other regions.”

HBD 101 – from malcolm pollack. (*^_^*)

bonus: A ‘Second Great Wave’ of immigration?“‘Once again, the country is approaching a percentage of foreign-born not seen since the late 1800s and early 1900s,’ the Census Bureau wrote on its blog this week.” – =/ – h/t ray sawhill!

bonus bonus: Muhammad’s birthplace to be razed – remember that the najdis hate the hejazis and vice versa.

bonus bonus bonus: Giant Virus, Awakened From 30,000-Year Slumber, Is Still Infectious – ruh roh (if you’re an amoeba)!

bonus bonus bonus bonus: Crawling Through The Brain Without Getting Lost“Do the wasps taste their way through a cockroach brain?” – mmmmmm! =/

bonus bonus bonus bonus bonus: Australia: Snake eats crocodile after battle – WITH PICTURES! =o – h/t ed west!

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