From a purely genetic standpoint, how does it make sense that the average IQ of African Ams is 85?

Great Debates
341

Right. Now back that up with any actual evidence.

Oh wait. You can’t. Because that evidence doesn’t exist, making this no more than a cute little hypothesis with absolutely no grounding in reality. You know, like most everything in this thread. What’s more, there’s serious confounding evidence that this would be the case, from the degree to which genetics is dependent on race to the intermixing of races to essentially everything population genetics has learned over the last decade or so.

Wait, you’re comparing a small african tribe to the entire rest of the world’s population? Okay, I’m sorry, but if you’re going to pull that analogy, let’s see the fucking data. I’m sorry, but you don’t get to weasel you way through this argument with poorly-chosen analogies and no actual evidence. We observe clear haplotypes in the Niolotic tribes - clear genetic variation that can be said to be typical of that group. This immediately makes them a poor choice for such a comparison. No, you need actual evidence.

342

Diversity of a group doesn’t have a thing to do with whether or not a given skillset difference is underpinned by genes. If, 50kya, a group that came out of africa developed a mutation different from the groups left behind, their descendant groups would have that gene and the groups left behind would not.

Genes cluster by SIRE groups, and some genes are so well penetrated that it’s very reasonable to suggest they have been positively selected for. MCPH1 has a haplogroup D variant that is 70% penetrated in Eurasians, but essentially not found in subsaharan africans, because of historical migration patterns.

It contradicts everything we know about evolution to pretend that human groups which have developed in relative isolation for tens of thousands of years should have similar genetic pools. One such isolating event was the migration out of africa some 70kya, and so one such (broad) division is africans v descendants of that out of africa group.

343

Are you just saying this because it seems like it should be true?

Do you have a counter cite to the many studies which show that average performance (the thing about which there is the most controversy in this thread) at a group level is not nearly as dependent on “parents” as it is SIRE group?

Black children of educated and wealthy families underscore white (and asian) children from uneducated and poor families. Are you asserting that these educated and wealthy black parents are incompetent in comparison with uneducated and poor white parents?

I am not saying parents don’t make a difference for an individual. A good parent can add to the nurturing for an individual so they will do better than they would with crummy parenting. But poor parenting, poor opportunity and lower SES are not the explanation for the failure to close the black-white score gaps in education at a group level average performance.

344

I feel the need to repeat myself, because you go on to say this:

Please clarify what races you think there are and why you classify them as such.

345

Well also if some allele (or set of alleles) emerged later and spread around, it’s reasonable to hypothesize that it spread to some parts of the world and not others.

Or to put it another way, if there is a collection of groups of people descended from groups in one part of the world; and a collection of groups of people descended from groups in another part of the world; and various differences are observed between those collections, it’s reasonable to hypothesize that those differences are informed by genetic differences. Regardless of the degree of diversity of those collections of people and regardless of their degree of relatedness.

346

Yes, as we’ve been saying- it’s a reasonable hypothesis, and nothing more. It’s just a hypothesis- and one that doesn’t fit all the facts. Other explanations actually fit the facts better.

347

Please read the whole thread, if possible, when you jump in late.

I use the term “black” or “white” or “asian” to refer to Self-Identified Race/Ethnicity, as the categories are laid out by the US Federal government.

348

Discomfort’s not the issue at all. We’ve done close to 20 of these threads over the past few years. We make no progress because white supremacist side of the debate is impervious to evidence and logic. They have no reasonable answer to the refutations of their position made by Frank Sweet, Ron Unz, or Richard Nisbett. Neither do they have any answer for the numerous scientists and knowledgeable laymen right here on the board.

The collection of innovations that we call civilization took place mainly in the fertile crescent - what is now Iraq. These innovations then spread to the Mediterranean Europe. Not places that have cold winters. In fact the colder parts of Europe were quite backwards until recently in world history.

The out of Africa cohort includes a variety of peoples who have low IQ scores as measured by modern testing. As low as black Americans, in the case of Pakistan, the more backwards parts of Europe before 1970, and many Arab nations. Lower than black Americans, in the case of Australian aborigines and New Guineans. As Unz and others have pointed out, there is so much volatility in IQ test scores over time that the changes can’t be genetic.

In Guns Germs and Steel, Jared Diamond points out that the ancestors of today’s New Guineans and Australian aborigines achieved a remarkable number of human firsts. They were, for a time in human prehistory, the most advanced people on the planet.

Now, they appear to be the most backwards. They certainly were much better able to survive in their environments than the first European settlers were.

If brain function were strictly analogous to heart, lung, and general muscle function, maybe. But brain function is so much more complex, so much less well understood. To make your hypothetical worth considering, you have to show how the various environments Africa failed to select for intelligence in the way that the sunny shores of the Mediterranean did. Aside from vague, absurd notions about the food just growing on trees in Africa, no one has done this. Primarily I think because the white supremacists don’t know much about Africa, and don’t care to learn.

You should ask how white Americans in the 1940’s “couldn’t know that”. Because their test scores were as low as black American’s test scores today, as measured by modern methods.

" In your experience". But you’re not really familiar with the literature, so you only have your impressions to go by. The critiques of Unz, Sweet, and Nisbett are based on good data and thorough review. Their positions aren’t “all or nothing”. Their positions are “The white supremacist argument doesn’t make sense when examined closely, and isn’t supported by the data.”

African kids in the States don’t have a test score gap. If you were familiar with the literature, then you’d know this. Of course, you’re conflating black Americans with Africans, which is seriously problematic for reasons that many posters have noted. The test score gap is primarily an American phenomenon. In Britain, African and West Indian kids actually outscore poor white kids.

Irrational speculation that has no place in a serious discussion.

Can you prove this? That is to say, can you point to a majority of black Americans or even a substantial minority who have explicitly rejected attempts to improve education, nutrition, health care?

A snap judgment, based on a few samples, on people and cultures you know nothing about? If I didn’t know better, I’d think that was ignorant and lazy.

349

I am aware of a small handful of widely-cited but non-rigorous newspaper articles stating this sort of thing, but I’m not aware of formal studies. Certainly in Britain there are some subgroups of african immigrants with occasional test scores reported above certain other (also poorer-class) white students. At a broad level across their educational system, though, this is not the case. Interestingly, immigrant asians do well in the British system, ranking approximately similarly to the way they do in the States and everywhere else.

There is a reasonable question also of whether or not (any) immigrant groups represent a reasonable cross-section of source populations or whether they represent an atypical subgroup; in particular the best and brightest who are most able to get out.

But as a broad theme across the world, you will be hard-pressed to find exceptions to the general rank order of SIRE groups, and this for me is a powerful circumstantial piece of evidence that genes are at play. In every culture and political system we will tend to see blacks overrepresented compared with starting pools for power sprinting sports. We’ll see asians at the top of the STEM science fields. It doesn’t matter if it’s Scandinavia or the US; we’ll see black kids struggling in the STEM sciences. The standard explanations for this vary according to the political system. Perhaps it’s a history of enslavement here; colonialization there; racism elsewhere; immigrant status in yet another place.

As we move into the post-slave/colonial/racism/immigration world, we’ll see how well things even out. In the US we are down to things like teacher expectations and poor parenting skills (ala Frank Sweet) to explain black-white skillset ability differences for standardized testing in schools even when the black pool is highly advantaged for wealth and education, and even when we do very broad studies averaging tens of thousands of SAT or ACT or MCAT scores or the like.

The social cost of this stubborn refusal to accept that we come from different genetic average pools is increasingly problematic. Universities have to skate around AA set-asides that assume equal opportunity will yield equal test score outcomes. Police forces and public companies using skillset testing hire consultants to weed out “cultural bias” in vain, and how to deal with fiascos like Ricci v DeStefano are commonplace problems for every municipality or public company.

Bad science makes for bad social policy, and pretending that Mbuti, Yoruba, Kalenji, and scandinavians/etc etc all draw from the exact same gene pool underpinning exactly equivalent success for skillsets represented in the modern world is a recipe for social constructs that never accomplish what we really need: a just and broad inclusion of every possible group within every possible niche.

350

The people who say race and gender are just made up, social constructs would remind me of the Emperor’s New Clothes, except I doubt they’ll ever achieve anywhere near as wide acceptance of their paradigm as he did (until that belief system collapsed). But then, religious people never fail to surprise me with how much nonsense large swaths of the population will swallow, so who knows.

I’m far from a white supremacist (as are people like Pinker and Dawkins); and I was born in Africa to parents who were an anthropologist and a sociologist living in a rural village and studying the local culture and health systems.

Beyond that, Chief Pedant keeps crushing this issue over and over, and it’s clear you have no rebuttal to offer beyond a few tangential nitpicks.

Actually, one more point. The people who explain away the fact that low SES whites score higher than high SES blacks, by saying it’s something cultural, should really go and hang out in a trailer park for a little while and then at a Jack and Jill country club. Then explain to me what cultural advantages are found in the trailer park. I would truly love to know.

351

Don’t forget peer-group pressure, and the very broad explanation I’ve offered- that there are obstacles to reaching academic and intellectual potential for the “black experience” in the US (and perhaps elsewhere) that are present regardless of economic or parental education status. Plus the “other” category that would include anything we haven’t thought of yet.

It certainly does seem both reasonable and likely that being black, even a wealthy and privileged black person, in America, would include non-measurable (at least so far) obstacles that are not present for non-black people.

352

CP presents no genetic evidence, and expects us to accept that, in this world of completely unequal opportunity, test-scores and other disparate outcomes can tell us anything at all about genetics.

There have always been disparate outcomes, and in the past, the groups on top and on bottom were totally different. I see no reason that now is so special that present disparate outcomes must reflect some perfect genetic hierarchy but outcomes in the past did not. Whatever social factors in the past caused these outcomes are likely still present, albeit in modified and lessened (in some case) forms. It’s just not reasonable to me that, after centuries of brutal oppression and the worst kind of dehumanization, followed by a century of slightly lessened institutionalized oppression, and just a few decades of actual legal equality, anyone would expect outcomes for that group to perfectly match the other groups.

Are we supposed to accept, without any actual genetic evidence, that it’s just coincidence that the group that was treated the most brutally in the US for centuries just happens to be the group that has the lowest “genetic potential” for high intelligence? Without genetic evidence- meaning, without knowing (all or most of) the genes that influence high intelligence- there’s just no reason at all to accept this, and many reasons not to.

353

Who here has claimed that “gender” is a “made up, social construct”?

354

One of the problems with any of these sorts of explanations is that they don’t explain the consistent patterns that we see very well.

For example, we see consistently larger differences in STEM fields over fields such as language or arts. It doesn’t seem likely that peer pressure creates lousy performance in one pursuit but not another. And remember we see score gaps for those sorts of fields regardless of parental education or wealth, so we can’t blame SES factors as drivers for differences in STEM fields. You will commonly see an explanation like “blacks underprepared for science and math” exams. But since the same pattern exists even with high SES privilege, it is not persuasive to argue that blacks somehow don’t have access to proper preparation. It’s much more likely that one takes advanced classes when one is good at something and does not pursue avenues where hard work is not rewarded with academic success.

See here for an article talking about black-white gaps on AP exams, and notice these same patterns exist.

It’s as if blacks need a special case explanation for why they, and not other oppressed/dark-skinned/immigrant/whatever groups underperform consistently on the same type of skillsets, and then a further set of machinations is needed to explain why this underperformance in turn consistently follows the same patterns which vary by subject (wrt the skillset of academic evaluations for STEM v social subjects).

Occam’s razor would suggest that the brains of different groups are wired differently. The evidence is that evolution affects all genes and these groups have evolved different gene pools from which they draw. As a consequence, their performance on various skillsets has a predictable pattern that is not erased even when nurturing is accounted for. But instead, you want to propose more and more complex nurturing variables, in special cases that are applicable only to “the black experience” because only the black group has that outcome. And despite 100 or more years of study, you want to suggest that we have not even thought of some variables. I suggest that these putative and vague new variables came about only when the traditionally-accepted nurturing variable of SES crapped out.

355

So you’ll have no problem giving BPC a solid definition of races, then?

Are black Americans, black Brazilians, Yorubas, Somalis, and Zulus all part of the same race? How about Sudanese Arabs? How about southern Portuguese?

Were we discussing gender? I don’t recall those posts. Maybe I missed them.

I never called you one. It’s fairly obvious that I was referring to posters in the numerous earlier threads. This doesn’t change the fact that the defenders of the white supremacist position are ignorant about Africa, and take a weird pride in their ignorance.

Your speculations about the out-of-Africa migrations are a bit silly, for the reasons I pointed out. You can go here for more in depth information.

Could you show exactly how Sweet, Unz, and Nisbett are engaging in tangential nitpicks? I’m curious. You could even contact them, they’re all generally open to critiques of their work.

Being white, by virtue of less segregation from the mainstream, less discrimination in housing and employment, and significant family ties to the mainstream of American life, is a substantial advantage in and of itself.

Actually, black Americans, even those with relatively high incomes, live in the most segregated communities in the US. On average, they’re far more cutoff from mainstream American life and culture than lower income whites.

http://www.pewtrusts.org/uploadedFiles/wwwpewtrustsorg/Reports/Economic_Mobility/PEW_SHARKEY_v12.pdf

http://www.chicagomag.com/Chicago-Magazine/The-312/February-2013/The-National-Press-Discovers-Chicagos-History/

356

Note that a “solid (I assume, biological) definition of races” is not a requirement in order to make a suggestion that an outcome difference is related to genes.

Neither is it required to make a suggestion that different races have different gene pools.

The “solid biological definition of races” is a strawman argument raised by those who want to get rid of genetic explanations by linguistic manipulations.

Suppose that I let people in the US self-categorize as “black” or “white.” I make no constraint whatsoever on them. They can assign themselves to “black” even if they are Navin Johnson.

The gene pools of these two groups will be different. That is, the average frequency of all sorts of genes will be demonstrably different from one group to the next. The chance, for example, that the self-assigned group of “black” will have sickle cell trait is vastly higher than the SIRE group of white. The self-assigned group of “white” will have lower creatine kinase reference ranges for their males.

Moreover, the self-assignment (Navin and any number of admixed folks notwithstanding) will surprisingly accurately reflect the predominate source pools from which their recent ancestry is derived, using an africa/out-of-africa splitting point in human migration history. This is true even though within the (arbitrary and self-assigned) group of “black,” subsets such as the Kalenjin and Mbuti are themselves markedly distinct genetically.

The inability to “define a race biologically” has nothing to do with the argument that black-white “race” outcomes are related to average genetic differences. If a gene arose in either broad group post the M/N (using mtDNA haplogroup markers, e.g.) split at the out of africa point, it would be available almost exclusively to the descendant populations inside the group within which it arose.

357

Own the book, read it years ago.

Addressing your links:

I love the Pew Center, and had I the time I would probably find it edifying to read that whole report. But you can’t just throw out a link to a PDF of a 40 page report, as one of four links in one part of one post of one thread on one debate board. How about quoting the portion you’d like to point to?

Also a regular reader and occasional commenter on TNC’s Atlantic blog. Interesting guy but way, way too pessimistic about the pervasiveness and effect of racism, given that he thinks it is getting worse and will destroy this country. I see a lot of progress and reason for optimism, but maybe that’s just me (no, wait–it’s not).

But even he, in the excerpt at your Chicago Magazine link, describes the housing exploitation of high-income blacks continuing “into the 1960s”. How you can cite that as an explanation for poor SAT scores by high-SEC black kids in 1995, I just don’t see. (Would BTW love if there were some more recent data than that–anyone know of some?)

Okay, then you just link separately to the blog post already excerpted at Chicago Magazine. Who is engaging in sloppy/lazy debating now? Sheesh.

Finally, another TNC link, and a more germane one: “A Rising Tide Lifts All Yachts”, discussing a Patrick Sharkey book with lots of excerpts. But this looks to me like a classic case of “lies, damn lies, and statistics”. The first Sharkey quote refers to blacks in the “top three quintiles”; since there are by definition only five quintiles total, this lumps the richest African Americans in with some who are below the median. Why would he do this? Was it necessary to massage the statistics this way to get the result he wanted? Comes across as fishy–some kind of detailed table or chart is needed here.

Then in the same quote, Sharkey goes on to say (since the “top three quintiles” group was born from 1955 to 1970): “This degree of racial inequality is not a remnant of the past. Two out of three black children born from 1985 through 2000 have been raised in neighborhoods with at least 20 percent poverty…” Wait, now we’re talking about the top five quintiles? What happened to this being a discussion of upper income blacks? Why can’t we just hear about the top quintile, or (dare I dream) maybe even decile? Would doing so reveal that such families do not tend to live in poor neighbourhoods, yet their kids still test poorly?

And if high-income African Americans are doing such a disservice to their kids by staying in these neighbourhoods, shouldn’t they move? I don’t think there’s any credible argument that (at least outside the Deep South, maybe) a high income family of any race can let their money do the talking in a tony suburb.

TNC refers to “spurious comparisons between Appalachia and Harlem”. Does he (and do you) really think dirt-poor Appalachian whites have a great shot at rising to the top echelons of SES? I would recommend reading Barbara Ehrenreich’s Nickel and Dimed. There is a yawning gulf, far beyond just money, between people raised in poor uneducated white rural America and those raised by white urban elites with longstanding connections and the knowledge of how to socially navigate the glass-and-steel jungle. That class divide is something I sincerely decry, among all races. But to pooh-pooh it for rural whites, to try to explain away a stunning and troubling IQ finding, does not sit well with me.

And so to argue that being a prototypical poor white person–say a rural white Kentuckyan, raised by a morbidly obese single mom along with four siblings, in a dilapidated trailer–gives you some kind of cultural advantage that allows you to do better on the SAT than a child raised by parents who have more money (and let’s face it, most likely quite a bit of education too in most cases outside of sports and entertainment) than my parents ever did or than I’ve ever had; parents who can hire tutors and send kids to private school and buy books and learning games and on down the line…I just find that way too much to swallow.

Now, just to be clear: if we were comparing straight across income lines, and whites did better, I would buy this. That is, if affluent blacks did worse than affluent whites, and poor blacks did worse than poor whites, but the race difference was a smaller one than the SES difference, I would buy that being black added an extra environmental disadvantage unrelated to genetics. And in fact, it probably does add such a disadvantage. But for that to be enough to cause the highest income blacks, who grew up way wealthier than I did, to score worse than the poorest whites, who grew up way poorer (and with way less cultural capital) than I did? No, that is a bridge too far.

And it kind of blows up my alternate non-genetic fallback hypothesis as well: that the IQ deficit mostly comes from lead poisoning. Unless wealthy blacks are still just hanging out in old buildings with lots of chipped paint everywhere–in which case, why on earth? Get outta there, rich black folks! C’mon now.

358

…Wow. Just… Wow. I…

Wow.

This statement is *phenomenally *dumb. Not quite as dumb as the idea that the average person in sub-saharan Africa is functionally retarded, but still really, really dumb. You are using self-identification as a basis for correlation in genetic markers? I… Wow. I don’t even know how to put into words how wrongheaded this is. Please tell me I’m misunderstanding you. Please tell me that if I’m not, you understand how dumb this is. I mean, shouldn’t it be obviously how far along *sociological *lines this draws? How much the “One Drop” rule, which runs completely contrary to population genetics, suddenly becomes a rule of thumb?

:smack: :smack: :smack: :smack: :smack:

Actually, the idea that “race” as we know it has any basis in biology - at least, races as in the major victorian-era races people like you or CP seem to want to prop up - has been utterly refuted by scientific sources. If you want to claim that “black” is a race, you’re simply wrong. If you want to claim that “asian” is a race, you are simply wrong.

At this point, you’re like the creationist accusing the evolutionary biologist of dogma and lack of evidence. It’s really quite humorous.

These “tangential nitpicks” include noting that his correlations completely fail basic rigor, and that he’s using self-identification in groups as genetic markers. If you want “crushing this issue”, check out C0nc0rdance’s videos on the subject, where he completely dismantles the concept of biological race.

No, but if the basis for that suggestion is “there is a difference between these two populations”, there’s a missing premise in there: that those populations have some consistent genetic differences or similarities. And when you use self-identification, that flies out the fucking window.

Well, I would say that in order to make that anything more than a poorly-thought-out hypothesis, you need actual evidence. How’s that coming for you? :rolleyes:

Nice hand-wave. Glad you’re addressing the major complaints about the rigor of your analysis. I wouldn’t demand a definition of race from you if you were using actual genetic terms like “cline” or “haplogroup” or “admixture”. Instead, you’re using “black” and “asian”. Those mean nothing in biology.

:smack:

And why would this mean anything? Why would this have any meaning? Seriously, you need to watch this video. At least the segment that link directs you to.

359

Blows your mind, don’t it, grasshopper?

The reason for your confusion is that you have gotten sucked down the “biological race” path and your entire egalitarian paradigm is constructed upon this mistaken assumption: For two groups with disparate outcomes to have genes as a principal driver for that disparity, they must be otherwise tightly-grouped genetically. Therefore if we can’t define “race” genetically, we can’t suggest differences are genetic.

It is this pervasive assumption that is badly wrong, and it’s unfortunate that it’s so blithely accepted.

We know, absolutely and without any scientific debate at all, that the average genetic pool for even self-assigned “race” groups differs. We know this because we have measured real genes with real penetration frequencies. Therefore there is absolutely nothing extraordinary or confused about assigning an average outcome discrepancy to a putative gene difference as long as the characteristic is known to be linked to genes.

Let’s try to help you with “tall.” I let everyone assign themselves to “tall” and “short.” Some overly optimistic folks assign themselves to “tall” when they aren’t anywhere near the average for that category. A bunch are in between. There is a gradual continuum of heights for the starting.

What happens? At the end of all of that, I have two groups, and the “tall” group will be taller than the “short” group. Moreover, genes–undefined, poorly characterized, etc etc–drive that difference along with nurturing influences.

OK, you might say, but is it so ridiculously arbitrary for self-assigned “race”? Well, no; it is not. The reason why is related to the long pattern of migration and evolution in humans that underpins this self assignment in the first place.

When humans came out of africa somewhere around 70kya, it was largely a one-way migration, and as various groups splintered off and continued peopling the earth, those groups were also relatively isolated (as compared with a total free admixture). We can track all of this with genetic studies on haplogroups, for example. So if a gene evolves when a group has left africa, there will be a gene prevalence difference for that gene versus the original gene. MCPH1 haplogroupD variant is an example, as I’ve pointed out before. It’s 70% penetrance into eurasian populations suggests that it is a highly positively selected gene. It is almost absent in “african” populations.

Remember, we are talking about averages here. We aren’t talking about individuals. Averages. Percentages. The kind of things that drive patterns; not individual results.

But this notion you have that it’s ridiculous to assign a genetic underpinning when we can’t “define a group biologically” is absolutely incorrect. It has no basis even without the history of human migration and evolution, because even arbitrarily or self-defined defined categories with outcome differences (tall and short, e.g.) might still have that difference because of genes.

I recommend additional reading to reassure yourself that there is a real biological construct associated with self-assigned racial categories, that humans really did migrate and create broad splits resulting in time-separated groups whose genes changed because of evolution, and that self-assignment to SIRE groups really does create categories that parallel surprisingly well with genetic ancestry which in turn contains average frequency disparities for genes.

You gotta get away from the newspaper columnists and the like and learn about the science. Then you’ll get the “wow.” Otherwise you just get inanity like some peanut-head arguing that genes can’t be at play if we can’t rigidly define a group genetically. Or you’ll read some idiot pretending the “one drop rule” (whatever that is) has anything to do with the price of rice in China.

360

It does?

From here.

"We have analyzed genetic data for 326 microsatellite markers that were typed uniformly in a large multiethnic population-based sample of individuals as part of a study of the genetics of hypertension (Family Blood Pressure Program). Subjects identified themselves as belonging to one of four major racial/ethnic groups (white, African American, East Asian, and Hispanic) and were recruited from 15 different geographic locales within the United States and Taiwan. Genetic cluster analysis of the microsatellite markers produced four major clusters, which showed near-perfect correspondence with the four self-reported race/ethnicity categories. Of 3,636 subjects of varying race/ethnicity, only 5 (0.14%) showed genetic cluster membership different from their self-identified race/ethnicity. On the other hand, we detected only modest genetic differentiation between different current geographic locales within each race/ethnicity group. Thus, ancient geographic ancestry, which is highly correlated with self-identified race/ethnicity—as opposed to current residence—is the major determinant of genetic structure in the U.S. population. Implications of this genetic structure for case-control association studies are discussed."

A little background reading on the actual science is always helpful before you get too excited about something a columnist has posted somewhere. But I welcome alternate cites.

FWIW, in the US, the typical percentage given for source population genes in self-defined black SIRE groups is about 80% african (historically, west african groups like the Yoruba because of the slave trade). For any given individual, it’s a wide range, which is why what is at issue is averages; not individuals.

I don’t care, really, to argue how we should define “race.” I’m not interested in arguments about language. I am interested in arguments about the extent to which observed outcomes in groups are driven by underlying differences in the average gene pool.