Thirty years of research on race differences in cognitive ability

Head size is correlated with brain volume, for obvious reasons. Therefore, the studies measuring head size correlate to brain volume differences, as well.

Based off the current consensus, the correlation coefficient for brain volume and intelligence is 0.40, while the for head size and intelligence it is 0.20.

Also note, head size/brain volume is correlated with height. This is why Rushton, the author, highlights that Asians, with the largest head/brain size, had the smallest stature; while Blacks, who were the tallest, had the smallest head/brain size.

Keep in mind that not one study measuring head/brain size for Asians, Blacks and Whites found equal size. The only 'studies' to reach these results were after Leftist researchers tinkered and fudged numbers of previous studies to reach their desired conclusion.

http://isites.harvard.edu/fs/docs/icb.topic185351.files/Rushton-Jensen30years.pdf

This second study using MRI to find brain volume differences between Blacks and Whites, which controlled for gender, age and educational achievement, found the similar differences in brain volume as an earlier MRI study between Blacks and Whites in Britain had found:



http://www.plosone.org/article/info:doi/10.1371/journal.pone.0013642

 

Rushton's research is pseudoscience. He deliberately misrepresented the findings of studies on race and cranial volume from other researchers to support his racialist ideas.

 

Northern Europeans have significantly larger brain volume than West African Blacks according to the study.

Rushton is attacked for using the study as one of many other studies showing racial hierarchy in brain volume and race.

Northern Europeans (Whites) have significantly larger brain volume than West Africans (Blacks).

In other words, the distinction without a difference fallacy.

 

Not according to Beals, Smith and Dodd (1984). They found that cranial volume and latitude were highly correlated and cranial volume and race had low correlations. The mean differences in cranial volume between continental populations were miniscule.

He is criticized for treating a study that clearly says that there's no relation between cranial volume and race as if it proves racial hierarchies in brain size when it doesn't.

No, they don't.

The difference between what Rushton reports and what Lieberman reports is that Rushton claims a causal relationship between brain size and intelligence as well as a racial hierarchy in brain size while Lieberman reports that brain size does not determine intelligence within the species normal range of variation and that there is no racial hierarchy. Rushton misinterprets studies, misrepresents them and ignores findings that invalidate his argument while Lieberman correctly interprets studies that support his argument.

 

Obviously the meaning of a distinction without a difference eludes you.

As opposed to Lieberman basing his work and conclusions off assumptions and unprovable belief.

"No, they don't" is not an acceptable response in a debate. Provide the actual mean cranial volume of Northern Europeans and West Africans or don't bother with a response.

The liar is still pretending Lieberman hasn't used studies based off assumptions and made unprovable claims.

That's ignoring the current consensus regarding brain volume and intelligence, as well as every actual study measuring brain volume and ethno-racial background.

 

Obviously the conclusions of the actual study elude you.

Deflection.

And that's still not a factual statement.

Maybe you didn't read Graves email:

As for supposed physical differences in head (or brain size). First, there has been no systematic measurement of cranial sizes for sufficient numbers of populations in humans. This is important because Africa and Asia are huge continents with many populations/ethnic groups. No physical measurement taken from 1 or a few populations could be expected to represent all Africans or Asians.

Mod edit,,,flounder

The consensus regarding brain volume and intelligence is that brain size does not determine intelligence within the species normal range of variation. This has been proven in several studies including one that showed that brain size does not determine intelligence within families.

Brain size does not predict general cognitive ability within families Proceedings of the National Academy of Sciences, U.S.A. 97:4982–87

Hominid brain size increased dramatically in the face of apparently severe associated evolutionary costs. This suggests that increasing brain size must have provided some sort of counterbalancing adaptive benefit. Several recent studies using magnetic resonance imaging (MRI) have indicated that a substantial correlation (mean r = ≈0.4) exists between brain size and general cognitive performance, consistent with the hypothesis that the payoff for increasing brain size was greater general cognitive ability. However, these studies confound between-family environmental influences with direct genetic/biological influences. To address this problem, within-family (WF) sibling differences for several neuroanatomical measures were correlated to WF scores on a diverse battery of cognitive tests in a sample of 36 sibling pairs. WF correlations between neuroanatomy and general cognitive ability were essentially zero, although moderate correlations were found between prefrontal volumes and the Stroop test (known to involve prefrontal cortex). These findings suggest that nongenetic influences play a role in brain volume/cognitive ability associations. Actual direct genetic/biological associations may be quite small, and yet still may be strong enough to account for hominid brain evolution.

 

http://psychology.uwo.ca/faculty/rushtonpdfs/2009 IJN.pdf

Why did you only reference the one study that failed to find a within family correlation? Were you simply unaware of the others and just happened to miss them?

 

What is your basis for calling Joseph Graves a hack academic? Don't think I'm going to let you get away with mindless name-calling in this discussion. Beals, Smith and Dodd (1984) didn't even measure brain volume so you can't say that their study shows significant differences in brain volume. Furthermore they didn't say that their measurements of cranial volume were representative of entire continents. That is Rushton's distortion.

Your flame-baiting has been reported.

Because it doesn't. Doh!

My explanation has been given above. Plus even if you were to take Rushton's reporting of mean cranial volume differences at face value (a misrepresentation of the study) the difference is not significant.

I didn't make that argument I simply reported the finding of the study. If there are other studies reporting something different I will take a look at them.

 

Funny you didn't address the fact you were caught lying when claiming the Beals study didn't show significant differences in brain volume/cranial size.

You're lying again. What does the Beals data for African and European skull size measurements say?

So which hack academic did you piggy-back from using this cherry-picked study?

Did you report yourself after calling me a charlatan?

 

It has?

What are these other studies you claim prove consensus that brain volume is not correlated with intelligence/IQ?

 

The biological anthropologist C. Loring Brace criticized Rushton in his 1996 review of the book, Race, Evolution and Behavior (1996):

Virtually every kind of anthropologist may be put in the position of being asked to comment on what is contained in this book, so, whatever our individual specialty, we should all be prepared to discuss what it represents. Race, Evolution, and Behavior is an amalgamation of bad biology and inexcusable anthropology. It is not science but advocacy, and advocacy for the promotion of "racialism." Tzvetan Todorov explains "racialism," in contrast to "racism," as belief in the existence of typological essences called "races" whose characteristics can be rated in hierarchical fashion (On Human Diversity: Nationalism, Racism, and Exoticism in French Thought, Cambridge, MA: Harvard University Press, 1993, p. 31). "Racism," then, is the use of racialist assumptions to promote social or political ends, a course that Todorov regards as leading to "particularly catastrophic results." Perpetuating catastrophe is not the stated aim of Rushton's book, but current promoters of racist agendas will almost certainly regard it as a welcome weapon to apply for their noxious purposes.[56]

Robert Sussman, an evolutionary anthropologist and the editor in-chief of American Anthropologist, explained why the journal did not accept ads for Rushton's 1998 book:

This is an insidious attempt to legitimize Rushton's racist propaganda and is tantamount to publishing ads for white supremacy and the neo-Nazi party. If you have any question about the validity of the "science" of Rushton's trash you should read any one of his articles and the many rebuttals by ashamed scientists.[57]

In 2000, after Rushton mailed a booklet on his work to psychology, sociology, and anthropology professors across North America, Hermann Helmuth, a professor of anthropology at Trent University, said: "It is in a way personal and political propaganda. There is no basis to his scientific research." Rushton responded, "It's not racist; it's a matter of science and recognizing variation in all groups of people."[58]

Since 2002, Rushton was the president of the Pioneer Fund. Tax records from 2000 show in that year that his Charles Darwin Research Institute was awarded $473,835, or 73% of the fund's total grants that year.[59] The Southern Poverty Law Center, an American civil rights organization, characterizes the Pioneer Fund as a hate group.[60][61] Rushton has spoken on eugenics several times at conferences of the American Renaissance magazine, a monthly racialist magazine, in which he has also published a number of general articles.[62]

Rushton published articles on the website VDARE, which advocates reduced immigration into the United States. Stefan Kühl wrote in his book, The Nazi Connection: Eugenics, American Racism, and German National Socialism (2002), that Rushton was part of the revival in the 1980s of public interest in scientific racism.[63]

Fantastic company to be keeping.

 

Why did a 2010 MRI study of Black and White cerebrum volume show Whites having 9% larger cerebrum than Blacks?

 

Sadly calling somebody a 'racist hate Nazi' when they point out facts of human variation doesn't disprove those facts.

 

So you have no basis for calling Graves a hack academic? Noted.

I'm not lying about the reported mean differences being insignificant. The normal species range of variation for cranial capacity is 1,000–2,000 cm[SUP]3[/SUP]. The mean difference in cranial capacity between Europeans and Africans reported by Beals et al.(1984) is 86cm[SUP]3[/SUP] (1,362cm[SUP]3[/SUP] vs. 1,276cm[SUP]3[/SUP]). So the mean difference is only about 8.6% of the normal variance, way too small to account for racial differences in intelligence.

As it is the point you keep eluding is that Beals et al. (1984) report a high correlation between cranial volume and latitude and a low correlation between cranial volume and race. This is not an insignificant finding. What it means is that racial background or continental ancestry is not a determinant of cranial capacity. The variance in cranial capacity between populations forms discordant geographic clines.

I got the study from the Lieberman article.

Jackson cites several recent studies that fully disprove Rushton’s linkage of brain size and cognitive ability. Most striking is the finding of no correlation between brain size and cognitive ability within pairs of siblings (Schoenemann et al. 2000:4932). Jackson refers to brain chemistry and the difficulty in linking cognitive-performance differences to a cocktail of chemicals in our brains. Hormones are also responsive to our behavior; it is another case of correlation’s not being the same as causation.

Source: How “Caucasoids” Got Such Big Crania and Why They Shrank From Morton to Rushton Current Anthropology Volume 42 , Number 1, February 2001

At first I decided to fire back at you with my own name-calling but I think it would be a more effective tactic to force you to be civil by reporting you to the Mods every time you violate the rules. Did you enjoy having your post deleted? I assure you that I will do it again should you decide to act up.

They're mentioned in the Lieberman article. You can look them up for yourself.

 

So what's the standard deviation for White cranial capacity? Tell me where the African mean falls on the normal distribution curve then get back to me whether the size differences are significant.

My guess is you don't know what you're talking about, as usual.

Thanks for letting me know the hack academic misrepresenting the literature on brain volume and IQ was.

Obviously, I'm not surprised Lieberman cherry-picked data.

 

The standard deviation for the range of variation in brain size within populations is about 130 cm[SUP]3[/SUP]. If you calculate the percentage of the standard deviation that the mean difference in cranial capacity takes up you come to a figure of about .6 SD units. Now multiply that by Rushton's reported figure for the correlation between g and cranial capacity as well as the reported figure for the Black-White IQ gap (15) and the Black-White gap in cranial capacity can not explain more than a tiny fraction of the Black-White IQ gap.

Rushton (this issue) claims that global differences in IQ and development can be explained in terms of (race) differences in brain size. Rushton (2000) has gone to great lengths to show that race groups differ on average in terms of brain size, with Whites averaging 1347 cm[SUP]3[/SUP] and Blacks averaging 1267cm[SUP]3[/SUP]. The mean difference may appear impressive, but it is virtually meaningless without knowledge of the typical spread of brain size within populations, which is around SD = 130 cm[SUP]3[/SUP]. So the Black-White difference in brain size is approximately 80/130  .6 SD units. Rushton’s figures are based not on contemporary MRI measurements of white and gray matter volume, but rather on outdated external or postmortem cranial measurements. Given the correlation between cranial capacity as measured externally and intelligence of around .20 (Rushton & Ankney, 2009), the Black-White gap in brain size cannot explain much of the IQ gap. Even if cranial capacity had a causal effect on g, then the Black-White gap in brain size cannot explain more than: .6*.2*15 = 1.8 IQ points. If we were to believe that the IQ gap between Africans and European Whites is 33 IQ points (Lynn & Vanhanen, 2006), then the brain size gap could explain a staggering 1.8/33 = 5% of the IQ gap. Thus, even under these terms, 95% of the IQ gap is left unexplained by brain size. With a correlation of .33 between brain volume and IQ as based on modern techniques (McDaniel, 2005), the gap in brain size can explain only 2.98 IQ points or 9% of the IQ gap.

Source: Evolution, brain size, and the national IQ of peoples around 3000 years B.C Personality and Individual Differences 48 (2010) 104–106

Actually it was Fatimah Jackson who reported the study if you read the article and it can hardly be called cherry-picking given that Rushton only reports 4 other studies that came to different results. Two of them apparently conducted by Jensen. It's not like there is a large body of work on this topic. Jackson might not have been aware of those studies or maybe the study she cited has better evidence.

 

This doesn't make any sense. Firstly, what is the variation in cognitive matter? What is the ratio of mean difference to 'range of variation' for IQ? Your calculation demonstrates nothing and is put together randomly. Of course variation in brain volume doesn't 'demonstrate' anything. It's simply a compelling line of evidence. You can't make calculations about it, that's really laughable. The simple fact that bigger brains mean higher IQs and some races have bigger brains and higher IQs is simply an indication. I'm not sure why your side fall over themselves blathering and lying trying to pretend it isn't the case. Do you find it compelling too?

Well obviously race doesn't 'determine' cranial capacity and nobody said that. It does correlate pretty well, especially for small brained Africans. Obviously the narrower race taxonomy you use the better the correlation, for example splitting Whites and Indians correlates much better than lumping them into Caucasoids. There is some race correlation. For example South Chinese have larger brains than Indians on the same latitude. Coincidence?

 

Bigger brains do not mean higher IQs. We know this because people with brains that are smaller than average can have high IQs. The size of the alleged difference in cranial capacity or brain volume does matter because it is an indication of how different the intelligence gap is supposed to be. If cranial capacity has a causal effect on intelligence then the difference in brain size ought to be able to explain most of the Black-White IQ gap. It doesn't. The reported difference is simply too small to take seriously the idea that it explains racial differences in intelligence.

Rushton's argument is that human races evolved different reproductive strategies to deal with the survival demands of their environment and that racial background determines a variety of Life-History tradeoffs including differences in brain size so yes he did argue that race determined cranial capacity. He didn't just argue that there is a correlation but being born to a certain race is the cause of inheriting different Life-History traits.

Do you have evidence that South Chinese have larger brains than Indians at the same latitude? I think I asked you this before. I don't recall you providing a source. As for splitting Europeans and Indians up rather than lumping them as Caucasoids that makes racial classification arbitrary and leaves open the possibility for ad hoc explanations for why certain facts don't fit the theory of races differing in intelligence. This is the type of selectivity of data led to heavy criticism of Rushton by several scholars. Indeed you could prove just about anything if you are selective in your interpretation and reporting of facts. Race is either a valid taxonomy or it isn't. How can you say Indians are only Caucasoids or not when it makes sense to you?

 

Rushton quite clearly stated the full range of variation was found in all groups and you are lying that anybody said race 'determines' anything.

Splitting a taxonomy into subgroups is standard, and in no way 'arbitrary'. This is just a silly name you dishonestly spit out.

 

Rushton said that human behavior is racially ordained. That sounds like race being a determinant of traits to me.

Did you say that Europeans and Indians were subgroups or that it didn't make sense to classify Indians as Caucasoids?

Are the people of India Caucasoids in your view or are they a separate race? What is your basis for racial classfication?

And where is the evidence that Indians have smaller brains than Southern Chinese at the same latitude?

 

Well how do you define 'determinant'? From what you wrote above you expected a one to one mapping, which is an old Communist anti genetics strawman. There is a correlation. The mapping is probabilistic.

Indians are Caucasoid. Race is based on genetic similarity. Obviously narrower subgroups match trait distributions more closely.

Look at the map. You can find India and China on a map?

 

I know where they are. I'm asking you for a source on brain size comparison between Indians and Southern Chinese.

 

Beals and Dodd's map is the source. You see the vertical (longitudinal) line between India and China? Yes or no will suffice.

 

yup the usual suspects posting Rushton racist pseudoscience crap...modern genetics thoroughly trashes all this garbage but that doesn't fit the racist narratives so best to ignore that and once again dig up Rushton's jibber jabber...

 

the there is the inexplicable evidence of smaller brained women consistently out performing men

http://www.sciencedaily.com/releases/2014/04/140429104957.htm
And then there is no explanation how a smaller than average brain einstien could be so brilliant, nope it's better to ignore the glaring contradictions to push the racist agenda...