# Can the Black-White racial IQ gap in the US be environmentally explained? **URL:** \ **Category:** Great Debates\ **Created:** [July 1, 2012, 4:56am UTC](https://boards.straightdope.com/t/can-the-black-white-racial-iq-gap-in-the-us-be-environmentally-explained/626877 "2012-07-01T04:56:56Z")\ **Posts on this page:** 20\ **Page:** 8
**Author:** ![Evil\_Economist](https://avatars.discourse-cdn.com/v4/letter/e/c89c15/32.png) [@Evil\_Economist](https://boards.straightdope.com/u/Evil_Economist)\ **Post date:** [July 9, 2012, 9:35pm UTC](https://boards.straightdope.com/t/can-the-black-white-racial-iq-gap-in-the-us-be-environmentally-explained/626877/141 "2012-07-09T21:35:01Z")
> [@NojNoj](#): > > Gee, I misplaced the study I did on that… > > But my sense is that most Americans with black skin color are descended from West Africans who survived forced transport in slave ships and then were able to survive generations of slavery. Ok, that seems like a factual claim which you should be able to support once you get access to the internet. I’ll leave that question open. Let’s just move on to my next question: if you believe that “most Americans with black skin color” “share a common genetic heritage”, and I’ll assume that you will also say that “Americans with black skin color” score lower than Americans with white skin color on IQ tests, and the difference is due to genetics…shouldn’t it be the case that the difference in IQ tests must increase with the “proportion of African ancestry” in the “Americans with black skin color”? ---
**Author:** ![NojNoj](https://avatars.discourse-cdn.com/v4/letter/n/2bfe46/32.png) [@NojNoj](https://boards.straightdope.com/u/NojNoj)\ **Post date:** [July 9, 2012, 9:42pm UTC](https://boards.straightdope.com/t/can-the-black-white-racial-iq-gap-in-the-us-be-environmentally-explained/626877/142 "2012-07-09T21:42:48Z")
I’m actually not familiar with the studies about American blacks and IQ tests, so would rather not comment on how rigorous they were or whatever. But I think your hypothesis is complicated by the nature of genetics. Who did the inter-breed with, who exactly comprises the population being studied, etc. Take American Jews and Tai-sachs (sp?) disease. I’ve read Ashekenazi Jews have somewhere between 40 to 60% of their genes that could be traced back to the mid-east (i.e., biblical times). The other percentage is made up of genes coming from whatever host country they were living in. So American Jews are a hodge-podge of genes from different nationalities, but as a group, they still have Tai-Sachs, while a German or Russian who didn’t interbreed with Jews doesn’t. (I.e., it’s not like there’s a spectrum of chances of getting Tai-Sachs) I think Genetics is too much of a mystery to say there’s “X%” chance depending on “y%” European vs. West-African blood. Of course, if you were a motivated racist and eager to show a difference, I suppose a better study would be to compare some homogenous group of West-Africans with a homogenous group of Iclanders. ---
**Author:** ![Evil\_Economist](https://avatars.discourse-cdn.com/v4/letter/e/c89c15/32.png) [@Evil\_Economist](https://boards.straightdope.com/u/Evil_Economist)\ **Post date:** [July 9, 2012, 9:49pm UTC](https://boards.straightdope.com/t/can-the-black-white-racial-iq-gap-in-the-us-be-environmentally-explained/626877/143 "2012-07-09T21:49:34Z")
> [@NojNoj](#): > > I’m actually not familiar with the studies about American blacks and IQ tests, so would rather not comment on how rigorous they were or whatever. > > But I think your hypothesis is complicated by the nature of genetics. Who did the inter-breed with, who exactly comprises the population being studied, etc. This kind of sounds to me like you are saying that American people with black skin don’t “share a common genetic heritage.” So, we would not expect “American people with black skin” to “vary in terms of their genetic component of intelligence” because people with black skin do not form a group of “people with similar genetic heritage.” Welcome to the club; you are now an “anti-racist”. ---
**Author:** ![NojNoj](https://avatars.discourse-cdn.com/v4/letter/n/2bfe46/32.png) [@NojNoj](https://boards.straightdope.com/u/NojNoj)\ **Post date:** [July 9, 2012, 9:53pm UTC](https://boards.straightdope.com/t/can-the-black-white-racial-iq-gap-in-the-us-be-environmentally-explained/626877/144 "2012-07-09T21:53:49Z")
I guess I’m saying is I’m not motivated enough by this issue to go searching around the internet to unearth exactly what percent of Americans with black skin share a common genetic heritage… I’ll stick to saying “Asians are smarter than everyone else.” I read it somewhere… ---
**Author:** ![Evil\_Economist](https://avatars.discourse-cdn.com/v4/letter/e/c89c15/32.png) [@Evil\_Economist](https://boards.straightdope.com/u/Evil_Economist)\ **Post date:** [July 9, 2012, 9:56pm UTC](https://boards.straightdope.com/t/can-the-black-white-racial-iq-gap-in-the-us-be-environmentally-explained/626877/145 "2012-07-09T21:56:23Z")
> [@NojNoj](#): > > I’ll stick to saying “Asians are smarter than everyone else.” I read it somewhere… Careful; if you do that, people will start asking difficult questions like: Do all Asians have a “similar genetic heritage”? ---
**Author:** ![Weirdering](https://avatars.discourse-cdn.com/v4/letter/w/4af34b/32.png) [@Weirdering](https://boards.straightdope.com/u/Weirdering)\ **Post date:** [July 10, 2012, 11:40am UTC](https://boards.straightdope.com/t/can-the-black-white-racial-iq-gap-in-the-us-be-environmentally-explained/626877/146 "2012-07-10T11:40:07Z")
> [@Evil\_Economist](#): > > Ok, that seems like a factual claim which you should be able to support once you get access to the internet. I’ll leave that question open. > > Let’s just move on to my next question: if you believe that “most Americans with black skin color” “share a common genetic heritage”, and I’ll assume that you will also say that “Americans with black skin color” score lower than Americans with white skin color on IQ tests, and the difference is due to genetics…shouldn’t it be the case that the difference in IQ tests must increase with the “proportion of African ancestry” in the “Americans with black skin color”? Most Americans with black skin color are of African descent. Most Americans of African descent share a common genetic heritage, that being West-African. ---
**Author:** ![monavis](https://avatars.discourse-cdn.com/v4/letter/m/e0b2c6/32.png) [@monavis](https://boards.straightdope.com/u/monavis)\ **Post date:** [July 10, 2012, 11:51am UTC](https://boards.straightdope.com/t/can-the-black-white-racial-iq-gap-in-the-us-be-environmentally-explained/626877/147 "2012-07-10T11:51:36Z")
> [@Chuck11](#): > > It’s well know that there’s a Black-White racial differences in intelligence and that this difference explains a large portion of the much discussed racial “disparities.” For example, Black psychologist Ronald Fryer recently replicated the findings of Neal and Johnson (1996) and Murray and Herrnstein (1994) in his 2010 article "[Racial Inequality in the 21st Century: The Declining Significance of Discrimination](http://www.nber.org/papers/w16256). What is not well known is the cause of the difference; though, frequently it’s blamed on purported ubiquitous White racism. Given the situation, specifically the moral imputations, we are forced to ask: **Is a complete environmental explanation, consistent with the facts on the ground, possible?** I recently re-outlined the background facts [here](http://unfaircampaign.wordpress.com/2012/06/23/are-disparities-really-due-to-white-racism/) and for the sake of brevity provided an abridged summary: > > Can anyone explain the differences environmentally in a way consistent with the data? I don’t think it is an IQ gap, just the opertunity to have good food etc. growing up, and the way some people think of it. All so called races have high and low IQ people. Judging people by their color is a low IQ way of looking at it!There is just one race and that is the human race. ---
**Author:** ![Evil\_Economist](https://avatars.discourse-cdn.com/v4/letter/e/c89c15/32.png) [@Evil\_Economist](https://boards.straightdope.com/u/Evil_Economist)\ **Post date:** [July 10, 2012, 11:54am UTC](https://boards.straightdope.com/t/can-the-black-white-racial-iq-gap-in-the-us-be-environmentally-explained/626877/148 "2012-07-10T11:54:37Z")
> [@Weirdering](#): > > Most Americans with black skin color are of African descent. Most Americans of African descent share a common genetic heritage, that being West-African. If you say so it must be so, I guess. Don’t bother supporting your claim or anything; you said it and that’s good enough for me. ---
**Author:** ![Weirdering](https://avatars.discourse-cdn.com/v4/letter/w/4af34b/32.png) [@Weirdering](https://boards.straightdope.com/u/Weirdering)\ **Post date:** [July 10, 2012, 12:03pm UTC](https://boards.straightdope.com/t/can-the-black-white-racial-iq-gap-in-the-us-be-environmentally-explained/626877/149 "2012-07-10T12:03:56Z")
At least when talking about race in the US, that should probably be considered general knowledge. Are you looking for exact numbers of ancestry proportions from a genome study, or numbers from a history of African slaves and immigrants to the US? ---
**Author:** ![Evil\_Economist](https://avatars.discourse-cdn.com/v4/letter/e/c89c15/32.png) [@Evil\_Economist](https://boards.straightdope.com/u/Evil_Economist)\ **Post date:** [July 10, 2012, 1:09pm UTC](https://boards.straightdope.com/t/can-the-black-white-racial-iq-gap-in-the-us-be-environmentally-explained/626877/150 "2012-07-10T13:09:28Z")
> [@Weirdering](#): > > At least when talking about race in the US, that should probably be considered general knowledge. Are you looking for exact numbers of ancestry proportions from a genome study, or numbers from a history of African slaves and immigrants to the US? Of course it’s general knowledge to you and me. It’s just that some of those guys over there are all skeptical and shit. Maybe you and me can find some sort of study showing: "Most Americans with black skin color are of African descent. Most Americans of African descent share a common genetic heritage, that being West-African. " You know, just to satisfy \*those \*guys. ---
**Author:** ![NojNoj](https://avatars.discourse-cdn.com/v4/letter/n/2bfe46/32.png) [@NojNoj](https://boards.straightdope.com/u/NojNoj)\ **Post date:** [July 10, 2012, 1:22pm UTC](https://boards.straightdope.com/t/can-the-black-white-racial-iq-gap-in-the-us-be-environmentally-explained/626877/151 "2012-07-10T13:22:08Z")
> [@Evil\_Economist](#): > > You know, just to satisfy \*those \*guys. Most historians now agree that at least 12 million slaves left the continent between the 15th and 19th century, but 10 to 20% died on board ships. Thus a figure of 11 million enslaved people transported to the Americas is the nearest demonstrable figure historians can produce.[63] In 1900, when the U.S. population was 76 million, there were 66.8 million Whites in the United States, representing 88% of the total population,[25] 8.8 million Blacks, with about 90% of them still living in Southern states,[26] and slightly more than 500,000 Hispanics.[27] In 2010, Black or African American = 38,929,319 Clearly, most of the 8.8 million recorded in 1900, living in the Southern States, were descended from, or were slaves. So, unless they all didn’t reproduce, and there was some secret migration of 10’s of millions of people from some other part of Africa (or somewhere else where someone might conceivably classify themselves as “black”), then only conclusion is that most of the 38 M recorderd in 2010 are descended in some way from the 8.8 M recorded in 1900. ---
**Author:** ![John\_Mace](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/john_mace/32/185_2.png) [@John\_Mace](https://boards.straightdope.com/u/John_Mace)\ **Post date:** [July 10, 2012, 1:40pm UTC](https://boards.straightdope.com/t/can-the-black-white-racial-iq-gap-in-the-us-be-environmentally-explained/626877/152 "2012-07-10T13:40:01Z")
“West African” is not an ethnic group. It’s a collection of ethnic groups. The data that I have seen indicates that so much interbreeding has taken place between blacks of different ethnic groups in the US, that most blacks are a mish-mash of the various West African ethnic groups. In order to trace their ancestry back to a particular group, you have to use something like Y-chromosome or mt-DNA analysis. But this only tells them where one of their great-great-…-great grandparents came from. It’s really not meaningful in the sense of determining a person’s ethnic background, genetically. And that assume you’re not someone like Skip Gates (of the Obama beer summit fame)-- he’s black, but his y-chromosome and mt-DNA both trace back to Europe, not Africa. Which is also true of a lot of white Americans, too, if their ancestors have lived here long enough. You may think you’re Irish or German or whatever, but you’re probably a broad mixture of different European ethnicities (with maybe some native American or black ancestry, too). Of course, many more white Americans than black have ancestors who immigrated here rather recently, so it’s not quite as pervasive in the white community as in the black. ---
**Author:** ![NojNoj](https://avatars.discourse-cdn.com/v4/letter/n/2bfe46/32.png) [@NojNoj](https://boards.straightdope.com/u/NojNoj)\ **Post date:** [July 10, 2012, 1:50pm UTC](https://boards.straightdope.com/t/can-the-black-white-racial-iq-gap-in-the-us-be-environmentally-explained/626877/153 "2012-07-10T13:50:22Z")
In this case, I’d grant you that not enough is know about which genes influence intelligence to say anything definitive. But for the sake of standing up for evolution, a lot of other different traits have been shown to be unique to all West-Africans as a broad category (Dr. Pritchard’s work). (I.e., in spite of variation among different ethnicities within West-Africa.) I’m just arguing that to accept evolution, you have to accept possibility that some broad groups will have lower results on IQ tests resulting mostly from genetics. This could just be complete randomness (founders’ effect or random drift), or could be something like mutation that protects you from Malaria also lowers intelligence, but natural selection chose Malaria protection as more important. ---
**Author:** ![John\_Mace](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/john_mace/32/185_2.png) [@John\_Mace](https://boards.straightdope.com/u/John_Mace)\ **Post date:** [July 10, 2012, 1:54pm UTC](https://boards.straightdope.com/t/can-the-black-white-racial-iq-gap-in-the-us-be-environmentally-explained/626877/154 "2012-07-10T13:54:41Z")
> [@NojNoj](#): > > In this case, I’d grant you that not enough is know about which genes influence intelligence to say anything definitive. Yeah, in the same sense that “not enough is known” about dark matter. Which is to say, almost nothing. > [@](#): > > But for the sake of standing up for evolution, a lot of other different traits have been shown to be unique to all West-Africans as a broad category (Dr. Pritchard’s work). (I.e., in spite of variation among different ethnicities within West-Africa.) > > I’m just arguing that to accept evolution, you have to accept possibility that some broad groups will have lower results on IQ tests resulting mostly from genetics. This could just be complete randomness (founders’ effect or random drift), or could be something like mutation that protects you from Malaria also lowers intelligence, but natural selection chose Malaria protection as more important. Of course we have to accept that possibility. Is anyone saying it’s impossible? If they are, then they’re wrong. ---
**Author:** ![NojNoj](https://avatars.discourse-cdn.com/v4/letter/n/2bfe46/32.png) [@NojNoj](https://boards.straightdope.com/u/NojNoj)\ **Post date:** [July 10, 2012, 2:03pm UTC](https://boards.straightdope.com/t/can-the-black-white-racial-iq-gap-in-the-us-be-environmentally-explained/626877/155 "2012-07-10T14:03:12Z")
> [@John\_Mace](#): > > Yeah, in the same sense that “not enough is known” about dark matter. Which is to say, almost nothing. > . For the sake of your intellectual reputation, I hope you meant “dark energy,” as the issue with “dark matter” is just figuring out which “dark” subatomic particle from a lot of potential candidates, is making it up 🙂 But even if specific genes haven’t been identified, and no one can say for sure, what aspect of brain structure corresponds with high “intelligence,” that there’s a strong genetic component to results of taking an IQ test seems pretty well established: > **[Heritability of IQ](https://en.wikipedia.org/wiki/Heritability_of_IQ)** > > Research on the heritability of intelligence quotient (IQ) inquires into the degree of variation in IQ within a population that is due to genetic variation between individuals in that population. There has been significant controversy in the academic community about the heritability of IQ since research on the issue began in the late nineteenth century. Intelligence in the normal range is a polygenic trait, meaning that it is influenced by more than one gene, and in the case of intell Early twin ... (And I think recent work argues that, if anything, genetics might make up a higher percent than has been estimated, since it appears that identical twins are even less identical genetically than people thought. ---
**Author:** ![John\_Mace](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/john_mace/32/185_2.png) [@John\_Mace](https://boards.straightdope.com/u/John_Mace)\ **Post date:** [July 10, 2012, 2:14pm UTC](https://boards.straightdope.com/t/can-the-black-white-racial-iq-gap-in-the-us-be-environmentally-explained/626877/156 "2012-07-10T14:14:25Z")
> [@NojNoj](#): > > For the sake of your intellectual reputation, I hope you meant “dark energy,” as the issue with “dark matter” is just figuring out which “dark” subatomic particle from a lot of potential candidates, is making it up 🙂 > > But even if specific genes haven’t been identified, and no one can say for sure, what aspect of brain structure corresponds with high “intelligence,” that there’s a strong genetic component to results of taking an IQ test seems pretty well established: > [Heritability of IQ - Wikipedia](http://en.wikipedia.org/wiki/Heritability_of_IQ) > > (And I think recent work argues that, if anything, genetics might make up a higher percent than has been estimated, since it appears that identical twins are even less identical genetically than people thought. If intelligence wasn’t hereditary, we’d be no smarter than chimps. ---
**Author:** ![NojNoj](https://avatars.discourse-cdn.com/v4/letter/n/2bfe46/32.png) [@NojNoj](https://boards.straightdope.com/u/NojNoj)\ **Post date:** [July 10, 2012, 2:26pm UTC](https://boards.straightdope.com/t/can-the-black-white-racial-iq-gap-in-the-us-be-environmentally-explained/626877/157 "2012-07-10T14:26:19Z")
> [@John\_Mace](#): > > Y > Of course we have to accept that possibility. Is anyone saying it’s impossible? If they are, then they’re wrong. Thanks for acknowledging that. When you point out that “West Africa” consists of many different ethnic groups you seem to be implying that one can’t hypothesize that a trait could be common and unique to all West-Africans broadly. (And clearly some are–if you showed me pictures of bald, Albino West-Africans and Northern-Europeans, I’d be able to guess the West-African 999/1000 times.) And you must be aware that many liberals do make the argument that variations in intelligence between groups is impossible (including in this thread). Besides the “there are no races” argument, there is also the “intelligence is so important, natural selection would lead everyone to have the same level” argument that you hear often. ---
**Author:** ![Evil\_Economist](https://avatars.discourse-cdn.com/v4/letter/e/c89c15/32.png) [@Evil\_Economist](https://boards.straightdope.com/u/Evil_Economist)\ **Post date:** [July 10, 2012, 2:35pm UTC](https://boards.straightdope.com/t/can-the-black-white-racial-iq-gap-in-the-us-be-environmentally-explained/626877/158 "2012-07-10T14:35:38Z")
> [@NojNoj](#): > > Thanks for acknowledging that. When you point out that “West Africa” consists of many different ethnic groups you seem to be implying that one can’t hypothesize that a trait could be common and unique to all West-Africans broadly. (And clearly some are–if you showed me pictures of bald, Albino West-Africans and Northern-Europeans, I’d be able to guess the West-African 999/1000 times.) > > And you must be aware that many liberals do make the argument that variations in intelligence between groups is impossible (including in this thread). Besides the “there are no races” argument, there is also the “intelligence is so important, natural selection would lead everyone to have the same level” argument that you hear often. OK, let’s assume that there is a “a trait common and unique to all West-Africans broadly.” Let’s call this the negative intelligence gene (everything here hypothetical), so that West Africans broadly have an average IQ of 85 and Europeans broadly have an average IQ of 100. Does this lead to testable implications? Let’s start with this one: does this indicate that people with a mix of West African and European genes should have an average IQ between 85 and 100? ---
**Author:** ![Belowjob2.0](https://avatars.discourse-cdn.com/v4/letter/b/b9e5f3/32.png) [@Belowjob2.0](https://boards.straightdope.com/u/Belowjob2.0)\ **Post date:** [July 10, 2012, 2:39pm UTC](https://boards.straightdope.com/t/can-the-black-white-racial-iq-gap-in-the-us-be-environmentally-explained/626877/159 "2012-07-10T14:39:31Z")
> [@NojNoj](#): > > Thanks for acknowledging that. When you point out that “West Africa” consists of many different ethnic groups you seem to be implying that one can’t hypothesize that a trait could be common and unique to all West-Africans broadly. (And clearly some are–if you showed me pictures of bald, Albino West-Africans and Northern-Europeans, I’d be able to guess the West-African 999/1000 times.) > > And you must be aware that many liberals do make the argument that variations in intelligence between groups is impossible (including in this thread). Besides the “there are no races” argument, there is also the “intelligence is so important, natural selection would lead everyone to have the same level” argument that you hear often. So, you can easily tell me what race these two athletes are: [http://daylife.sky.com/imageserve/08WB4TCclp9x6/x500.jpg](http://daylife.sky.com/imageserve/08WB4TCclp9x6/x500.jpg) And these two: [http://images.supersport.com/Hong%20Kong%206bg.jpg](http://images.supersport.com/Hong%20Kong%206bg.jpg) ---
**Author:** ![NojNoj](https://avatars.discourse-cdn.com/v4/letter/n/2bfe46/32.png) [@NojNoj](https://boards.straightdope.com/u/NojNoj)\ **Post date:** [July 10, 2012, 2:42pm UTC](https://boards.straightdope.com/t/can-the-black-white-racial-iq-gap-in-the-us-be-environmentally-explained/626877/160 "2012-07-10T14:42:38Z")
> [@Evil\_Economist](#): > > Let’s start with this one: does this indicate that people with a mix of West African and European genes should have an average IQ between 85 and 100? I appreciate your effort to read and appreciate my argument. I’d fall back on the argument I made in the “blacks are better runners” thread about dominant alleles: \*According to the last few paragraphs of this article: [http://www.nytimes.com/2006/03/07/sc...98800&emc=eta1](http://www.nytimes.com/2006/03/07/sc...98800&emc=eta1) advantageous mutations in a “block” of DNA can easily sweep through an entire population so eventually everyone carries them. Further, some alleles can show “complete dominance,” so even in a heterozygote individual, the phenotype is still that of having fast sprinting adaptations. So, someone of West-African descent, even if 49% of their genome is European, so long as the 51% carries the positive adaptation, they’re going to be an extra fast sprinter… \* Obviously the issue with intelligence is it’s not positive to have less of it, unless it’s somehow clustered with genes that confer some other advantage (thus, example of malaria resistance). So, if that cluster is completely dominant, and you carry it, doesn’t matter how much of your genome is European. [Previous page](https://boards.straightdope.com/t/can-the-black-white-racial-iq-gap-in-the-us-be-environmentally-explained/626877.md?page=7) [Next page](https://boards.straightdope.com/t/can-the-black-white-racial-iq-gap-in-the-us-be-environmentally-explained/626877.md?page=9)