The Instigator
Pro (for)
7 Points
The Contender
Con (against)
0 Points

Genetic differences explain racial IQ gaps

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Voting Style: Open Point System: Select Winner
Started: 4/16/2016 Category: Science
Updated: 2 years ago Status: Post Voting Period
Viewed: 1,702 times Debate No: 89774
Debate Rounds (4)
Comments (6)
Votes (1)




Many thanks to my opponent, Grovenshar, for accepting the debate! For anyone else interested, comment here (

- Pro and Con will avoid debating the merits of IQ as a metric, or race as a classification system. While these are certainly debatable, being largely seperate and rather nuanced subjects, they would be best suited to their own debates.

Note that, as a result, race will not be defined for the purposes of the debate. Given that virtually all data on the subject relies on self-identification, there should be no need for it either.
- BOP is initially shared but can be debated/shifted
- No new points should be brought up beyond Round 3
- No forfeits
- No kritiks
- My opponent will not attempt to define "race" for the purposes of the debate
- All sources must be provided in-text of the debate
- Keep it civil
- Violation of the rules merits a loss

- Pro will argue that racial IQ gaps are owed to genetic differences between racial groups. At least to a significant degree.
- Con will argue that the racial IQ gaps are not owed to genetic differences between racial groups. Either in the absolute, or to any non-negligible extent

Round 1 = Acceptance
Round 2 = Opening arguments
Round 3 = Response to opponents' opening arguments
Round 4 = Defense of own opening arguments, closing statements


Thanks for the challenge. I hope that we have a good debate.
Debate Round No. 1


Genetic cause as the default hypothesis:

- Distinct populations

We must begin with the acknowledgment that the populations which are commonly referred to as "black", "white"/European, Asian, etc. - or generally, the races of mankind - are genetically distinct and distinguishable.

For example, a 2010 paper found that: "using all available SNPs, assignment of individuals to their self-reported populations of origin is essentially perfect." [4]

As Neven Sesardic wrote on the matter: "Indeed, a quick look into the literature confirms this. For instance, a study that covered 17 populations over the world and that relied on 34 different measurements managed to assign 98% of the specimens to their correct major racial group (Brues 1990, 6). Another more recent study had a success rate of 80% in distinguishing between American Whites and Blacks, although it used just two variables. With seven variables, however, it reached the reliability of 95%, and with 19 variables the probability of correct classification rose to 97% (Ousley et al. 2009). Also, estimating generally the reliability of attributing a given data point to one of the five racial categories, another team of experts calculated that under some realistic conditions it is sufficient to use as few as 13 characteristics to have the posterior probability of the correct classification attain the value of 99% (Konigsberg et al. 2009)."
[3] (emphasis mine)

For a visual representation of these distinctions, refer to Figure 1 from Zakharia et al. 2009 [1] :
Zakharia et al. 2009
This principal comonent analysis (PCA) chart plots the genetic distance between Europeans, African-Americans, and a variety of African populations.

Another PCA chart, made with data from (see Table 5), shows the following arrangement:
(The particular clusters are Nigerian (sky blue), European (green and red), and Northeast Asian (purple and blue))

- Other differences, or, why would evolution stop at the neck?

So now that we have conclusively established human "races", as they are popularly thought to exist, are in fact distinct groupings. Of course, this by itself does not tell us anything. Humans have been dispersed throughout the world for dozens of thousands of years, of course there would be genetic marks of such migrations. But does this make it reasonable to expect important differences - those that can influence phenotype - beyond mere superficials?

The answer is, of course, yes! It is very well established that, among other things, different human populations differ in:

- Susceptibility to sickle-cell disease [14]
- Suitability to live at high altitudes [15]
- Cranial structure
- Brain size [17]
- Brain structure [16]

- Probability of the a priori assumption

Regarding mental abilities, and other race differences, anthrpologists Gregory Cochran and Henry Harpending wrote in The 10,000 Year Explosion: "the biological equality of human races and ethnic groups is not inevitable: In fact, it’s about as likely as a fistful of silver dollars all landing on edge when dropped" (p. 121). There is simply no reason to assume or expect uniform selection.

In the absence of evidence, it is significantly more likely that racial gaps in IQ are genetic than otherwise. But we don't have to speculate, given that which is already available.

Historic-genetic precedent and evidence:

- Neanderthal ancestry

One of the most damning pieces of evidence in favor of the genetic explanation, is the uneven degree of Neanderthal ancestry between the races [12].

Some argue that Neanderthal admixture was likely neutral, and had no effects on populations that received it. However, this argument is extremely dubious. For one example, take the FOXP2
gene, which is required [5] for proper speech development. A 2007 paper [6] found that Neanderthals carried the same variation of the gene that modern humans do - before us. Anthropologist Henry Harpending wrote [7] on the subject: "I don't know how else to explain that except to suggest we got it from Neanderthals"

- Population differentiation

There is evidence that concerns the genomic impact of human evolution. Take for example, Wu and Zhang's 2011 paper [8] on population differentiation on functional genes:
Wu and Zhang 2011
Figure 1 [8]

Note the level of differentiation in pigmentation, as opposed to that of, say, neuron or hindbrain development.

Explanatory power and consistency:

- Accross the economic spectrum

The racial differences in average IQ also persist in spite of economic disparities. For a few examples, refer to the following table:

Made with World Bank [10] and Census [9] income data, as well as Lynn and Vanhanen's global IQ data [11], the table shows next-to-no association between IQ and socioeconomic status. Certainly not enough for a causal relationship.

- Mixed-race people

As a hereditarian position would predict, the average IQs of mixed-race people fall between those of their parents' populations. A 2014 article [13], which analyzed 31 studies on racial admixture, found that their results "support a racial hereditarian hypothesis along with others that predict a fairly internationally consistent association between continental ancestry and cognitively correlated indices of socioeconomic status such as education, income, and job prestige" [13].


It has been demonstrated that the populations recognized as "races" are significantly distinct in a genetic sense, that these genetic differences lead to a variety of important phenotypic differences in a multitude of areas, and that there is no good reason to assume cognitive capacity would be an exception. It has also been demonstrated that, given the uneven history of admixture with archaic hominids, consistence and persistence of the gaps, and GWAS analyses, the evidence favors a genetic explanation for at least part of the IQ gaps..

At this point, the important question is not "why should we believe this?", but rather, "why should we expect anything else?"




Grovenshar forfeited this round.
Debate Round No. 2


Con has forfeit, round goes to Pro


I need to apologize. I forfeited due to the copious amounts of work that I have recently received from my classes in addition to PARCC testing. I have not given up on the debate. That is an erroneous assumption. Now, moving on to my opponents arguments.

First off, the definition of race, as provided by my opponent, is a self fulfilling prophecy. The definition was built off of an assumption that it could be defined via genetic markers. Ergo, to prove these genetic markers correct, a study was conducted to see if they were present in people of a certain race. Before they could test the genetic markers, they first had to define what race somebody was in to test the accuracy of the hypothesis. Therefore, there is no accuracy because the genetic definition, at that point in time, was not tenable and cannot be used now due to a subjective, rather than objective, labeling of race. However, I will, for the sake of argument, let this one fly.

Now, let's look at evolution. My opponent proposes that the human brain would change over the time of "dozens of thousands of years", especially in isolation. It is possible that there will be differences in the power of brains, but, as has been noted with numerous cases of feral children, children who were somehow lost in the wild, that the human brain does not naturally develop IQ. This takes outside interference. Therefore, IQ is a product of nurture, rather than nature. To assume otherwise is an irrational attempt at ethnicism, and cannot be tolerated.

So, let's look at the attempt to debunk the power of nurture in the development of IQ. My opponent points to a table that maps countries, including "African Americans", by socio-economic status relative to IQ. What we see is that wealth doesn't make a difference. I will not dispute that. Wealth never has, and it never will make a difference. What does make a difference is cultural attitude. You will notice that China has the highest mean IQ. As was noted in the book "Outliers", by sociologist Malcolm Gladwell, Asians tend to do better at math. However, this is due to their language being more suited to math, not the students being more apt. The language has numbers of two English characters, or less, in length. The English language has numbers of up to five characters and two syllables in length. The Chinese language is more apt.

In addition to this singularly damning evidence that culture, not genetics, truly determines IQ, I bring up the traditional cultural values of the Chinese people. Once again, according to "Outliers", the Chinese people put roughly 2000 hours of work into their farms every year. That's twice the number of hours other cultures put into their work every year. Their is a clear focus on hard work. Traditional proverbs center on this. We can also see that other cultures, that also put a heavier emphasis on hard work, can have similar results. Recently, in primarily low socio-economic status neighborhoods, a middle schooling system, known as KIPP, has emerged. KIPP puts its students through classes from 7 A.M. in the morning till 5 P.M. in the afternoon while, simultaneously, giving students a minimum of three hours of homework a night. This program has officially created students that perform exceedingly well at science and mathematics, areas generally associated with IQ. Ergo, we can assume that upbringing and cultural values affect IQ, not genetic differences. Let us remember, without civilization, we are all just another group of monkeys living in the wild.
Debate Round No. 3


Defense of the racial category

No one and precise definition was provided in the studies cited. They relied on subjects self-identifying their ethnicity, which was then shown to correspond with actual genetic ancestry and cluster virtually all of the time. This shows that racial concepts, as popularly held by people, do in fact help to identify genetically distinct populations. While this may not be true of formalized racial definitions, it should be noted that such aren't particularly popular outside of academia.

Feral children

Con argues that feral children - children who have lived apart from other humans for most of their development - do not "naturally develop IQ".

The first problem with this argument is that IQ is not a trait that has to be developed. IQ is a metric made to evaluate a trait (intelligence/cognitive capacity/g).

Feral children can and have [1] performed IQ tests either way. They tend to score lower than average (at least initially, depending on age), likely due to factors such as poor nutrition. Animals can be tested for IQ too - even though most have no culture to speak of, let alone one that could influence their results.

Asian languages and mathematical ability

In response to the high performance of Northeast Asians relative to other populations, Con argues that this is due to the structure of their language. Not an inherent characteristic.

Of course, it's very easy to test this claim. By looking at the Programme for International Student Assessment (PISA) test results [2], separated by race and nationality, we can determine whether academic performance is tied more closely to the genetic population, or to language.

Note that even though Asian Americans do not speak Northeast Asian languages at nearly the same rate as those in Asia [3], they perform about as well as the international Asian average. It should be noted that certain populations (such as Ashkenazi Jews), which do not commonly speak NE Asian languages, regularly ouperform Asians in mathematics.

Culture and IQ

Finally, Con states that culture is ultimately what explains IQ and the gaps, not inheritance. For one example, he cites the amount of hours worked by the Chinese as evidence of their hardworking culture. However, industriousness has virtually no connection with IQ [5].

To more diretly examine Con's theory, we can look at populations that are culturally exchangeable but genetically distinct. For example, Ashkenazi as opposed to Shepardi Jews.

Despite sharing a studious Jewish culture, the Ashkenazi score, on average, around 14 points higher than the Sephardi [4]. As a 2006 paper demonstrated [6], the genetic-origin model can explain these differences, given the Ashkenazi's particular history and selective pressures underwent in Europe.

Either way, the cultural model simply cannot explain the IQ gaps. This is evidenced by the fact that IQ gaps are largest in the least culture-loaded (and most heritable) tests [7].


1] Curtiss, S., Genie: A Psycholinguistic Study of a Modern-Day “Wild Child” (New York: Academic Press, 1977), cited in F. E. Bloom & A. Lazerson, Brain, Mind, and Behavior (2nd ed.), (New York: W. H. Freeman and Company, 1985), 266-267.


Before I move forward, I feel I should clarify one thing. IQ can, and does, change over time [1]. This is due to changes in the structure of the brain, which occur very frequently until the age of 25, when the brain calms down a bit. The changes in the brain are always traced to two factors, outside stimuli and genetic predisposition. Ergo, we can conclude that these changes are affected by the outside, by things like culture. While genetic predisposition plays a role, it isn't measurable. Therefore, we must conclude that culture has a greater affect on the IQ of any given person than genetics.

Definition of Race:
This was a miscommunication by both sides. I will concede my opponents definition of race.

Feral Children:
Just to clarify, I meant that IQ doesn't develop into larger IQ naturally. Education and other factors do so much more to develop IQ than something like nutrition. If malnutrition leads to lower IQs, it's not because of a mysterious link, it's because children in that environment don't have access to education.

To further push through my point that culture affects IQ, let me point out that my opponent noted that the children in question didn't perform as well on IQ tests at first, depending on age. This demonstrates that people's IQs can change and improve over time due to the influence of education.

Asian Languages and Mathematical Ability:
When we take a look at the PISA, we find that Asians truly are better at all of the things. The only score to breach 600 in the entire world is Shanghai. Everybody else is less than 575 on the scores. Ergo, to say that the Ashkenazi Jews outperform Asians is a lie, an entire lie. I won't lie that Ashkenazi Jews do well, but I can say that there are other factors in play.

As for the performance of American Asians vs. the non-American Asians in language, we must conclude that language can be learned by anybody, as long as there is an environment to support it. People can become fluent in languages if they have a fluent speaker to talk to. Any other assumption is just false.

Culture and IQ:
Industriousness in education leads to higher IQ's. Traditionally, the Asian population worked more than any other population in the world. That background has recently been trodden upon because of the advent of globalization. However, that industriousness gets put into education instead. As has been noted with the KIPP programs, industriousness in education leads to improvements in intellectual capability, and, therefore, IQ.

The source my opponent uses to explain the differences between these two cultures performance on tests follows through with a school of evolutionary thought known as Lamarckism or gradualism. Gradualism is the idea that as a particular muscle or organ is used, its functionality increases in subsequent populations. This was debunked a century ago. Evolution occurs through natural selections, which is the process of those who have certain genes that allow them to live in an environment being more capable to pass those genes on, because they are actually alive to produce offspring. The only explanation can be found in what a lot of sociologists refer to as "cultural evolution". Whatever the difference is in the two "culturally exchangeable" cultures leads to this increased intelligence. Any other premise is ethnicist, racist, and false.

YouTube Video:
The YouTube video that is presented does show some evidence, but most of it is based on success, not IQ. Consider how many people are white that have the percentage of success that the Jews have. It's a case of opportunity, not merit.

Final Conclusion:
It is impossible to conclude that genetics are the sole reason that intelligence is different between different ethnicities. It's possible that on some microscopic level that certain people will have more intelligence than others, but the effects of culture on the brain mask it so thoroughly so that it is impossible to detect. If anybody reading this debate wants to look into further research, I would suggest the book "Outliers", by Malcolm Gladwell.

1 -
Debate Round No. 4
6 comments have been posted on this debate. Showing 1 through 6 records.
Posted by SolonKR 1 year ago
This vote of mine really makes me cringe looking back. I was wrong on a lot of levels:
1. I shouldn't have put the BoP on Con. The "why would evolution stop at the neck?" point doesn't hold up; there's nothing particular about China, for instance that would select for "high IQ" for a sustained period of time that other places don't have. Natural selection requires lower-IQ people to die more and reproduce less than higher-IQ people, and that doesn't happen especially in China or Europe. In some places like the present-day U.S., people with higher IQs are less likely to reproduce, after all. My misunderstanding of evolution caused me to incorrectly assess the BoP.
2. I overstated the strength of Pro's case. The "mixed race" point, for instance, is unconvincing; most people's IQs fall between the IQs of their parents, and this correlation holds regardless of race. Identical twin studies show IQ is pretty heritable, but jumping from that to "some races have inherently lower IQs" is too big of a leap to make, as IQ also has a large environmental component.

I apologize for the terrible vote and my stupidity in casting it.
Posted by someloser 2 years ago
Holy jesus you're alive
Posted by SolonKR 2 years ago
Popping back on for a moment because there's two things I need to fix about my original vote.

1. It should read, "Unfortunately, he never quantifies the extent to which the gap is affected, and so he never proves that race doesn't impact IQ to a "significant degree"."

2. In light of new information I have read on the subject, calling the resolution a truism was really, really dumb on my part, and I apologize for that.

That said, someloser still did win the debate.
Posted by someloser 2 years ago
Forgot to specify - data for the second PCA chart is from source [2].
Posted by Stonehe4rt 2 years ago
Shhhh.. this isnt your debate.... Though i do the same thing some times so I guess I am being a bit of a hypocrite.... But yeah I do agree with you, it isnt based on genetics, while in some cases Genes can affect intelligence with things like Down syndrome however those are genetic problems. not the common geno.

However to say it is blacks that are disadvantaged would be incorrect. It is the impoverished that are disadvantaged (Shocking right?) A vast amount of poverty in America is actually Black yet the African American Race is actually a minority. Meaning a great big percentage of black people in America are actual poor. Is this their fault? Inherently it is not. In fact they are still suffering from the enslavement and cruelties that American hit them with not even 100 years ago. Only two or so generations. While many white families have parents who have already gotten in a stable economic position and can assist their children. Rather to say it is blacks who are disadvantaged, it would be better to say that Whites took the advantage from them. The poverty that these families got stuck in breeds more poverty which breeds lower levels of intelligence which causes the IQ gap between race. In fact this happens enough that is may end up affecting them genetically as their bodies will adapt to have a smaller brain due to it not being used as much as others. This is also something that happens to children who are neglected. It is the same situation, America in a sense is neglecting our Poverty, even though we give Welfare, we don't try our hardest to help. We could do more to make up for the horrible things that America has done, but of course that would cost a lot of money, and we are already in debt.
Posted by Americarnage 2 years ago
Heredity has nothing to do with the racial IQ gap. It's more to do with the fact that a) 12% of Americans are black, yet 30.2% of welfare recipients are black. We can blame this on b) percentage of blacks in the inner city (a dominant minority of whom likely have menial/unobtainable aspirations) and c) government funds into blacks vs. d) black contribution to government funds.
Taking all these factors into consideration puts us at liberty to say that blacks are ideologically disadvantaged, to put it nicely.
1 votes has been placed for this debate.
Vote Placed by SolonKR 2 years ago
Who won the debate:Vote Checkmark-
Reasons for voting decision: Pro shows that, because different racial groups are different in many respects other than pigmentation, including brain size and structure, assuming genetic differences are primarily responsible for IQ differences is the default position, shifting the BoP to Con. His evidence of mixed-race parents having children with IQ's in between the parental races also demonstrates this. Con points out that there are other explanations besides race that exist--cultural background and upbringing--and he shows that there are certainly other factors in determining racial IQ gaps, especially in countries like China. Unfortunately, he never quantifies the extent to which the gap is affected, and so he never proves that race impacts IQ to a "significant degree". I find the resolution as defined a bit of a truism, but Con doesn't fulfill the BoP, so I'm voting Pro.