# Statistically, blacks score poorly on IQ and IQ-proxy exams than whites, is black genetics to blame? **URL:** \ **Category:** Great Debates\ **Created:** [August 29, 2011, 12:43pm UTC](https://boards.straightdope.com/t/statistically-blacks-score-poorly-on-iq-and-iq-proxy-exams-than-whites-is-black-genetics-to-blame/594488 "2011-08-29T12:43:51Z")\ **Posts on this page:** 20\ **Page:** 16
**Author:** ![tomndebb](https://avatars.discourse-cdn.com/v4/letter/t/b9e5f3/32.png) [@tomndebb](https://boards.straightdope.com/u/tomndebb)\ **Post date:** [September 7, 2011, 4:06am UTC](https://boards.straightdope.com/t/statistically-blacks-score-poorly-on-iq-and-iq-proxy-exams-than-whites-is-black-genetics-to-blame/594488/301 "2011-09-07T04:06:51Z")
> [@Chen019](#): > > So if a test reveals that a child is intellectually handicapped, or that a person on death row lacks the mental capacity to form intent, you would dismiss it because they only measure a limited range of skills? In fact, when we test kids for developmental delay, we generally do test them for specific failures to grasp aspects of language or math or whatever. No IEP would ever rely on a Stanford-Binet to set out its program. Similarly, the capacity to form intent is a specific, not a generalized, capacity and a person my suffer from that deficit while still being quite competent in various aspects of math or reading or other skills. ---
**Author:** ![tomndebb](https://avatars.discourse-cdn.com/v4/letter/t/b9e5f3/32.png) [@tomndebb](https://boards.straightdope.com/u/tomndebb)\ **Post date:** [September 7, 2011, 4:09am UTC](https://boards.straightdope.com/t/statistically-blacks-score-poorly-on-iq-and-iq-proxy-exams-than-whites-is-black-genetics-to-blame/594488/302 "2011-09-07T04:09:09Z")
> [@Chen019](#): > > Populations, or at least major geographic populations essentially mean the same thing as [race](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC139378/). And once again you trot out the claims of people examining the immigrant populations of the U.S. while trying to expand the definition to mean the populations of the entire world. ---
**Author:** ![Chen019](https://avatars.discourse-cdn.com/v4/letter/c/f19dbf/32.png) [@Chen019](https://boards.straightdope.com/u/Chen019)\ **Post date:** [September 7, 2011, 4:17am UTC](https://boards.straightdope.com/t/statistically-blacks-score-poorly-on-iq-and-iq-proxy-exams-than-whites-is-black-genetics-to-blame/594488/303 "2011-09-07T04:17:08Z")
> [@tomndebb](#): > > In fact, when we test kids for developmental delay, we generally do test them for specific failures to grasp aspects of language or math or whatever. No IEP would ever rely on a Stanford-Binet to set out its program. > Similarly, the capacity to form intent is a specific, not a generalized, capacity and a person my suffer from that deficit while still being quite competent in various aspects of math or reading or other skills. Here is the definition in the context of intellectual disability by the [American Association on Intellectual and Developmental Disabilities (AAIDD):](http://www.aaidd.org/content_185.cfm?navID=62) > [@](#): > > What is intelligence? > Intelligence refers to a general mental capability. It involves the ability to reason, plan, solve problems, think abstractly, comprehend complex ideas, learn quickly, and learn from experience. Although not perfect, intelligence is represented by Intelligent Quotient (IQ) scores obtained from standardized tests given by a trained professional. > > With regards to the intellectual criterion for the diagnosis of intellectual disability, limitations in intellectual functioning are generally thought to be present if an individual has an IQ test score of approximately 70 or below. IQ scores must always be considered in light of the standard error of measurement, appropriateness, and consistency with administration guidelines. Since the standard error of measurement for most IQ tests is approximately 5, the ceiling may go up to 75. This represents a score approximately 2 standard deviations below the mean, considering the standard error of measurement. It is important to remember, however, that an IQ score is only one criterion: Significant limitations in adaptive behavior skills and evidence that the disability was present before age 18 are two additional criteria in determining if a person has intellectual disability. > .. > > AAIDD applauds and fully supports the U.S. Supreme Court decision to stop executing persons with intellectual disability. AAIDD has always advocated against the death penalty of people with intellectual disabilities and has long served as amicus curiae in Supreme Court cases. In 2001, AAIDD and eight other disability organizations presented an amicus brief to the U.S. Supreme Court advocating against the death penalty in the Atkins case. ---
**Author:** ![Chen019](https://avatars.discourse-cdn.com/v4/letter/c/f19dbf/32.png) [@Chen019](https://boards.straightdope.com/u/Chen019)\ **Post date:** [September 7, 2011, 4:19am UTC](https://boards.straightdope.com/t/statistically-blacks-score-poorly-on-iq-and-iq-proxy-exams-than-whites-is-black-genetics-to-blame/594488/304 "2011-09-07T04:19:15Z")
> [@tomndebb](#): > > And once again you trot out the claims of people examining the immigrant populations of the U.S. while trying to expand the definition to mean the populations of the entire world. Not true, you get the same thing with samples from around the world: > [@](#): > > In summary, we have studied the same worldwide population > sample as Rosenberg et al. (2002) with a set of > 40 biallelic slow-evolving short insertion-deletion polymorphisms. > We found that the genetic structure of the > populations included in the HGDP-CEPH Diversity > Panel is best portrayed by a picture of the world divided > into genetic clusters that tightly correspond to > five geographic regions: America, Sub-Saharan Africa, > East Asia, Oceania and a group composed of Europe, > the Middle East and Central Asia. laboratoriogene.info/Cientificos/Annals.pdf ---
**Author:** ![Der\_Trihs](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/der_trihs/32/233_2.png) [@Der\_Trihs](https://boards.straightdope.com/u/Der_Trihs)\ **Post date:** [September 7, 2011, 4:29am UTC](https://boards.straightdope.com/t/statistically-blacks-score-poorly-on-iq-and-iq-proxy-exams-than-whites-is-black-genetics-to-blame/594488/305 "2011-09-07T04:29:12Z")
> [@tomndebb](#): > > Beyond that, of course, even if a few random slave owners did practice breeding, it was never a common event and the actions on a handful of plantations throughout the Southern U.S. would have had no chance to actually modify the physical characteristics of the entire group in the limited time available to them. And even if they had it _still_ wouldn’t matter, given just how much uncontrolled breeding there has been since then. Anything achieved by selective breeding would have long since been eliminated. ---
**Author:** ![Zoe](https://avatars.discourse-cdn.com/v4/letter/z/a4c791/32.png) [@Zoe](https://boards.straightdope.com/u/Zoe)\ **Post date:** [September 7, 2011, 7:33am UTC](https://boards.straightdope.com/t/statistically-blacks-score-poorly-on-iq-and-iq-proxy-exams-than-whites-is-black-genetics-to-blame/594488/306 "2011-09-07T07:33:38Z")
> [@](#): > > **Chuck11** : In this case, “intelligence” is operantly defined as “general mental ability (GMA).” “General mental ability” is, in turn, defined as the common variance shared by a battery of tests. And test scores on a battery of tests measure (imperfectly) only those things that the designers of the test decide are to be measured. That dog has ahold of his tail. After following the link on psychometrics, I see that they are still searching for “the Holy Grail” – an understanding of what _intelligence_ is. Should they measure social intelligence? How? Should they test for physical intelligence? What about resourcefulness? (That’s an old chestnut from 1926.) On and on. To their credit, they admit that they haven’t untangled it yet. And **Chen019’s** quote from the AAIDD admits that measurement is imperfect. > [@](#): > > **magellan** : Funny you should say that. A black friend of mine (super-smart by the way) often says that he wishes that blacks would never play sports. Hi reasoning is that it gives a huge swath of kids false hope. Better that they don’t dream of hitting that jackpot and buckle down in school. This situation does not ring true for the inner city schools that I taught in. I never had students that were so carried away with the dream that they didn’t buckle down in school. To the contrary, they worked extra hard in my classes because they had to make the grade to be elligible for the football or basketball teams. The coach and I worked as a team ourselves. I didn’t give an inch on their grades, but I did let them train when they did well on their work. Anyway, I’d didn’t hear much talk about “pie in the sky.” They hadn’t seen much of that from the neighborhood. I did have two students that were with with Cowboys and the Dolphins for at least a short time. Neither of them were ever a problem while they were students. Just rascals. Your friend has limited thinking and has forgotten all of the benefits that sports provide high school students _in the present_ while they are still in school and in the future in the way of scholarships and memories and self-confidence. It’s hard to believe your friend was ever in school with other blacks. ---
**Author:** ![magellan01](https://avatars.discourse-cdn.com/v4/letter/m/45deac/32.png) [@magellan01](https://boards.straightdope.com/u/magellan01)\ **Post date:** [September 7, 2011, 2:07pm UTC](https://boards.straightdope.com/t/statistically-blacks-score-poorly-on-iq-and-iq-proxy-exams-than-whites-is-black-genetics-to-blame/594488/307 "2011-09-07T14:07:46Z")
> [@Ibn\_Warraq](#): > > Countless sexually unsatisfied white women can testify to it’s veracity. Countless? As in zero? Or do you have some other countless number in mind? > [@Ibn\_Warraq](#): > > My mother was very glad she didn’t marry an anatomically inferior white man. Good for her. She chose a mate that had the attributes important to her. Other women might have selected for IQ. Evidently, as you say, she chose otherwise. ---
**Author:** ![Ibn\_Warraq](https://avatars.discourse-cdn.com/v4/letter/i/e19b73/32.png) [@Ibn\_Warraq](https://boards.straightdope.com/u/Ibn_Warraq)\ **Post date:** [September 7, 2011, 3:52pm UTC](https://boards.straightdope.com/t/statistically-blacks-score-poorly-on-iq-and-iq-proxy-exams-than-whites-is-black-genetics-to-blame/594488/308 "2011-09-07T15:52:38Z")
> [@magellan01](#): > > Good for her. She chose a mate that had the attributes important to her. Other women might have selected for IQ. Evidently, as you say, she chose otherwise. What makes you think she wasn’t concerned about “IQ”. She selected someone from the cradle of civilization who spoke multiple languages with advanced degrees. By contrast had she selected a white American not only would she have chosen someone anatomically inferior but she’d probably have selected someone morbidly obese who was too dumb to speak more than one language. ---
**Author:** ![iiandyiiii](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/iiandyiiii/32/7924_2.png) [@iiandyiiii](https://boards.straightdope.com/u/iiandyiiii)\ **Post date:** [September 7, 2011, 3:58pm UTC](https://boards.straightdope.com/t/statistically-blacks-score-poorly-on-iq-and-iq-proxy-exams-than-whites-is-black-genetics-to-blame/594488/309 "2011-09-07T15:58:46Z")
> [@magellan01](#): > > Good for her. She chose a mate that had the attributes important to her. Other women might have selected for IQ. Evidently, as you say, she chose otherwise. Way to confirm that you automatically assume ANY individual black man has a lower IQ. ---
**Author:** ![magellan01](https://avatars.discourse-cdn.com/v4/letter/m/45deac/32.png) [@magellan01](https://boards.straightdope.com/u/magellan01)\ **Post date:** [September 7, 2011, 4:13pm UTC](https://boards.straightdope.com/t/statistically-blacks-score-poorly-on-iq-and-iq-proxy-exams-than-whites-is-black-genetics-to-blame/594488/310 "2011-09-07T16:13:14Z")
> [@Ibn\_Warraq](#): > > She selected someone from the cradle of civilization who spoke multiple languages with advanced degrees. So you say. > [@Ibn\_Warraq](#): > > By contrast had she selected a white American not only would she have chosen someone anatomically inferior but she’d probably have selected someone morbidly obese who was too dumb to speak more than one language. So, you’re of the mind that even Population A might, on average, have a larger X than Population B, that means that all members of Population A have larger Xs than population B? I’m beginning to see why you have a problem with the whole race and IQ thing, you don’t understand basic logic. The conclusions you’re drawing are fallacious. ---
**Author:** ![magellan01](https://avatars.discourse-cdn.com/v4/letter/m/45deac/32.png) [@magellan01](https://boards.straightdope.com/u/magellan01)\ **Post date:** [September 7, 2011, 4:16pm UTC](https://boards.straightdope.com/t/statistically-blacks-score-poorly-on-iq-and-iq-proxy-exams-than-whites-is-black-genetics-to-blame/594488/311 "2011-09-07T16:16:08Z")
> [@iiandyiiii](#): > > Way to confirm that you automatically assume ANY individual black man has a lower IQ. Sorry. I see how you got there, but that is not a belief I hold at all. I don’t even know if Blacks, on average, have lower IQs. But even if they do, it does not hold that an individual Black man has a low IQ. Or lower than the White average. Or lower than any random White man. ---
**Author:** ![Chuck11](https://avatars.discourse-cdn.com/v4/letter/c/96bed5/32.png) [@Chuck11](https://boards.straightdope.com/u/Chuck11)\ **Post date:** [September 7, 2011, 4:31pm UTC](https://boards.straightdope.com/t/statistically-blacks-score-poorly-on-iq-and-iq-proxy-exams-than-whites-is-black-genetics-to-blame/594488/312 "2011-09-07T16:31:35Z")
Hmmm. Who banned me? ---
**Author:** ![Fotheringay-Phipps](https://avatars.discourse-cdn.com/v4/letter/f/d9b06d/32.png) [@Fotheringay-Phipps](https://boards.straightdope.com/u/Fotheringay-Phipps)\ **Post date:** [September 7, 2011, 4:52pm UTC](https://boards.straightdope.com/t/statistically-blacks-score-poorly-on-iq-and-iq-proxy-exams-than-whites-is-black-genetics-to-blame/594488/313 "2011-09-07T16:52:11Z")
> [@orcenio](#): > > Allow me to point out that humans are not dogs nor are they bred. A poodle is a breed, it is both genetically homogenous and standardly different then other homogenous dog breeds. Humans are not bred. “the black race” is not a genetically homogenous dog breed. it is not genetically homogenous at all. This point has been made repeatly in many threads. You failed to understand the point I was making. “The black race” (to use your term) is analogous to “South Side dogs” in my example. My point was that group characteristics can differ with genetic basis even in the absence of “genetically homogenous” groups. ---
**Author:** ![Chuck11](https://avatars.discourse-cdn.com/v4/letter/c/96bed5/32.png) [@Chuck11](https://boards.straightdope.com/u/Chuck11)\ **Post date:** [September 7, 2011, 5:07pm UTC](https://boards.straightdope.com/t/statistically-blacks-score-poorly-on-iq-and-iq-proxy-exams-than-whites-is-black-genetics-to-blame/594488/314 "2011-09-07T17:07:18Z")
> [@Zoe](#): > > And test scores on a battery of tests measure (imperfectly) only those things that the designers of the test decide are to be measured. That dog has ahold of his tail. > > After following the link on psychometrics, I see that they are still searching for “the Holy Grail” – an understanding of what _intelligence_ is. Should they measure social intelligence? How? Should they test for physical intelligence? What about resourcefulness? (That’s an old chestnut from 1926.) On and on. To their credit, they admit that they haven’t untangled it yet. You obviously didn’t understand the article. If you take a look at the diagram, in the article, you will see g at the apex of the ability hierarchy. This is what all measures of intelligence converge on and what they all share. It’s what gives a measure of GMA it’s generalizability. What is unknown is the exact psychoneurophysiological architecture of it.If you’re not familiar with the psychometric literature refer to the following review papers: (Neurobiology of GMA) 1. [The neuroscience of human intelligence differences](http://www.larspenke.eu/pdfs/Deary_Penke_Johnson_2010_-_Neuroscience_of_intelligence_review.pdf) (Predictive validity and reliability of GMA) 2. [General Mental Ability in the World of Work: Occupational Attainment and Job Performance](http://www.unc.edu/~nielsen/soci708/cdocs/Schmidt_Hunter_2004.pdf) (GMA in industrial organization) 3. [Role of General Mental Ability in Industrial, Work, and Organizational Psychology](http://lesacreduprintemps19.files.wordpress.com/2011/05/role-of-general-mental-ability-in-industrial-work-and-organizational-psychology-deniz-s-ones.pdf) (GMA in life) 4. [g, jobs, and life](http://www.udel.edu/educ/gottfredson/reprints/2005g-jobs-life.pdf) When it comes to group differences, this is what we are talking about. A difference in some trait called general mental ability which has all sorts of educational, psychological, neurological, and social correlates. Which can partially explain the different mental retardation and giftedness rates, differences in [trainability](http://psycnet.apa.org/journals/apl/96/1/34/), differences in overal [work performance](http://psycnet.apa.org/journals/apl/88/4/694/), differences in [scholastic ability](http://lesacreduprintemps19.files.wordpress.com/2011/06/sacketshen.pdf), and so on. ---
**Author:** ![Chuck11](https://avatars.discourse-cdn.com/v4/letter/c/96bed5/32.png) [@Chuck11](https://boards.straightdope.com/u/Chuck11)\ **Post date:** [September 7, 2011, 5:27pm UTC](https://boards.straightdope.com/t/statistically-blacks-score-poorly-on-iq-and-iq-proxy-exams-than-whites-is-black-genetics-to-blame/594488/315 "2011-09-07T17:27:27Z")
> [@magellan01](#): > > So you say. > So, you’re of the mind that even Population A might, on average, have a larger X than Population B, that means that all members of Population A have larger Xs than population B? I’m beginning to see why you have a problem with the whole race and IQ thing, you don’t understand basic logic. The conclusions you’re drawing are fallacious. The African husband was likely immigrant selected (i.e. +2 SD above the population mean or in the top 2.2%). Only a small percent of African-Africans both 1) have multiple degrees and 2) immigrate. Anyways, if this was the case, he could have been superior on that account to the majority of American Whites available. You would have to compare him to the pool of available mates. ---
**Author:** ![Chuck11](https://avatars.discourse-cdn.com/v4/letter/c/96bed5/32.png) [@Chuck11](https://boards.straightdope.com/u/Chuck11)\ **Post date:** [September 7, 2011, 5:46pm UTC](https://boards.straightdope.com/t/statistically-blacks-score-poorly-on-iq-and-iq-proxy-exams-than-whites-is-black-genetics-to-blame/594488/316 "2011-09-07T17:46:31Z")
> [@tomndebb](#): > > Again, you are moving the goalposts all over, using a smattering of polls from non-biologists, (with, interestingly enough, a decided trend toward avoiding the word “race.” . I asked for a citation that supported your claim about biologists. You were unable to give me one. If you can’t back up your claims, don’t make them. Anyways, I’m not interested in debating this here. > [@](#): > > I have read lots of those claims. They are unpersuasive. > And if an intelligence difference was caused by educational deprivation, then it would cease to be a genetic issue. Ok, so you agree that within-groups the difference is largely due to genetics – as opposed to education? Would you agree that, by adulthood, the heritability of IQ, within groups, approaches .70 – at least in the US? ---
**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:** [September 8, 2011, 12:29am UTC](https://boards.straightdope.com/t/statistically-blacks-score-poorly-on-iq-and-iq-proxy-exams-than-whites-is-black-genetics-to-blame/594488/317 "2011-09-08T00:29:50Z")
> [@](#): > > Ok, so you agree that within-groups the difference is largely due to genetics – as opposed to education? Can’t be true. The [Flynn effect](http://en.wikipedia.org/wiki/Flynn_effect) has happened too rapidly to be due to genetics. ---
**Author:** ![Chen019](https://avatars.discourse-cdn.com/v4/letter/c/f19dbf/32.png) [@Chen019](https://boards.straightdope.com/u/Chen019)\ **Post date:** [September 8, 2011, 12:42am UTC](https://boards.straightdope.com/t/statistically-blacks-score-poorly-on-iq-and-iq-proxy-exams-than-whites-is-black-genetics-to-blame/594488/318 "2011-09-08T00:42:25Z")
> [@Belowjob2.0](#): > > Can’t be true. The [Flynn effect](http://en.wikipedia.org/wiki/Flynn_effect) has happened too rapidly to be due to genetics. Within group variation is significantly due to [genetic variation](http://www.guardian.co.uk/science/2011/aug/09/genetic-differences-intelligence). > [@](#): > > To test his idea, researchers looked at more than half a million locations in the genetic code of 3,511 unrelated adults. Each of these sites is where people are known to have single-letter variations in their DNA, called single nucleotide polymorphisms (SNPs). These variations were correlated with the individuals’ performance in two types of psychometric tests that are established in assessing intelligence: one test measuring recalled knowledge (via vocabulary) and the second measuring problem-solving skills. > > They found that 40% of the variation in knowledge (called “crystallised intelligence” by the researchers) and 51% of the variation in problem-solving skills (“fluid-type intelligence”) between individuals could be accounted for by the differences in DNA. The results are published on Tuesday in the journal Molecular Psychiatry. Also, see results of previous [twin studies](http://infoproc.blogspot.com/2011/07/heritability-20.html). ---
**Author:** ![SciFiSam](https://avatars.discourse-cdn.com/v4/letter/s/47e85d/32.png) [@SciFiSam](https://boards.straightdope.com/u/SciFiSam)\ **Post date:** [September 8, 2011, 1:27am UTC](https://boards.straightdope.com/t/statistically-blacks-score-poorly-on-iq-and-iq-proxy-exams-than-whites-is-black-genetics-to-blame/594488/319 "2011-09-08T01:27:18Z")
I don’t really see the point of all the cites about different parts of the world excelling in different sports, beyond what would be expected of their cultures. If you live somewhere where having a big lung capacity has been selected for then that’s not going to be bred out of your descendants just because they move to the lowlands. They might also have a similar skin colour to you. Tall people have an advantage when playing basketball, and height is largely genetic (esp. in countries with good nutrition), but cultural expectations play into success at a sport; in Europe, where basketball has never been a huge sport, Northern European countries (esp. Scandinavia and Holland) do dominate, and they tend to have taller people. Still, they’re not competing on an equal level with teams in the US where basketball has been popular for much longer. But that’s got nothing to do with intelligence, because intelligence is useful everywhere. Sporting prowess is completely irrelevant to this thread, yet it’s been one of the main discussions on it. ---
**Author:** ![Chen019](https://avatars.discourse-cdn.com/v4/letter/c/f19dbf/32.png) [@Chen019](https://boards.straightdope.com/u/Chen019)\ **Post date:** [September 8, 2011, 1:29am UTC](https://boards.straightdope.com/t/statistically-blacks-score-poorly-on-iq-and-iq-proxy-exams-than-whites-is-black-genetics-to-blame/594488/320 "2011-09-08T01:29:31Z")
> [@SciFiSam](#): > > But that’s got nothing to do with intelligence, because intelligence is useful everywhere. Sporting prowess is completely irrelevant to this thread, yet it’s been one of the main discussions on it. You’d be surprised, some people can’t stomach the thought of different cultures and environments favouring different physical traits let alone mental ones. [Previous page](https://boards.straightdope.com/t/statistically-blacks-score-poorly-on-iq-and-iq-proxy-exams-than-whites-is-black-genetics-to-blame/594488.md?page=15) [Next page](https://boards.straightdope.com/t/statistically-blacks-score-poorly-on-iq-and-iq-proxy-exams-than-whites-is-black-genetics-to-blame/594488.md?page=17)