Brain Size and Intelligence: A Positive Correlation

by Ryan Cavallius

EVEN THOUGH IT HAS BEEN DIFFICULT for researchers to determine the exact causes of individual differences in intelligence, they are known to be largely hereditary, and there are a number of biological factors with strong correlations to IQ. One such factor is relative brain size, that is, the size and weight of one’s brain in proportion to one’s body mass. Scientists refer to this as the “EQ,” or encephalization quotient.

EQ measurements have helped to identify a strong positive correlation between intelligence and brain size among different species, races, and individuals. For example, species of high intelligence usually have larger brains than species of low intelligence in proportion to their body size, with Homo sapiens having the largest brains of all. Brain size also correlates to intelligence within our species, as more intelligent races have, on average, larger brains than less intelligent ones. And this correlation is also observable from one individual to the next within a given race, for intellectually gifted men have often been found to have larger than average brains. So while it would be erroneous to assume that brain size itself determines intelligence, ample research has shown that there is a positive statistical correlation between the two.1

Research cited by Richard Lynn2 in his Race Differences in Intelligence has shown that among living species the average encephalization quotient increases in the following ascending order: fish and reptiles, 0.05; average birds, 1; average mammals, 1; marmoset, 1.5; squirrel, 1.8; gorilla, 2; rhesus monkey, 2.1; hamadryas baboon, 2.4; chimpanzee, 2.6; Homo sapiens, 7.5.3 The conclusion is obvious: Those species with larger brains in proportion to their body size are more intelligent, and with humans there is a giant leap in brain size corresponding to our much higher intelligence. This is not a new revelation, either. As long ago as 1956, eminent neurologist C.J. Herrick wrote, “It is obvious from simple inspection that the relative mass of the cerebral cortex corresponds in a general way with the grade of learning capacity and intelligent behavior …learning capacity increases progressively from lower to higher animals and …this increase is dependent upon enlargement and especially upon differentiation of the cortex.”4

Brain size differences can also be readily observed between the various races of man, and here too those differences in weight, development, and overall size show a marked correlation with intelligence. In the book cited above, Lynn refers to more than fifteen studies which all point to measurable differences in brain size from one race to the next. In one table, he gives an extensive list of brain sizes for different races which shows that Australian Aborigines have the smallest brains (approximately 1225 cubic centimeters, on average), followed by the Bushmen (1270 cc), African Negroes (1282 cc), Europeans (1369 cc), and Northeast Asians (1416 cc).5 The average IQs for these races are, respectively, 62, 55, 71, 100, 105. The Inuits and related peoples are a major outlier here, for they have the largest average brain size (1443 cc) of any race, but – apart from a “strong visual memory ability”6 – a considerably lower average IQ (91) than what might otherwise have been expected.

In the knowledge of these racial differences, again we have nothing new. During the nineteenth century, men like Charles Darwin and Paul Topinard noted the correlation between brain size and intelligence as well as their unequal distributions between the “savage” races and the “civilized” ones.7 This was around the time that Samuel Morton was assembling a collection of skulls and measuring their cranial capacity to show a difference in the brain sizes of certain races. While his sample size was small and his method of measurement rudimentary by modern standards, Morton’s work nevertheless indicated what later research proved: The races of man differ in their average brain sizes, just as they do in their intelligence.8 When, a century and a half later, Morton’s work was finally replicated and improved upon in the most comprehensive study of this sort ever performed, approximately 20,000 crania were measured according to a uniform method — and the results confirmed that the human races which are known to have the highest IQs also have more cranial capacity.9

Regarding brain size and intelligence at the individual level, here too a strong positive correlation has been observed. In his landmark text Race, John R. Baker, former Professor of Biology at Oxford University, recounted various cases in which the brain sizes and cranial capacities of intellectually distinguished Europeans were measured. After accounting for some error in the results of certain studies (partly due to rudimentary methods of measurement), Dr. Baker affirmed that indeed the brains of highly intelligent men appear to be, on average, larger than those of the rest of the population. “There is no evidence,” he wrote, “that any illustrious person ever had a brain that was very small in comparison with those of normal Europeans, and it would appear that sufferers from microcephaly are invariably idiots.”10

In their review “The Evolution of Brain Size and Intelligence,” professors J.P. Rushton and C.D. Ankney cited 55 studies that recorded external head measurements and 27 that measured brain size using brain imaging techniques such as MRI and CT: Every single one showed a positive correlation with IQ. Rushton and Ankney also referred to five studies which assessed the correlation between head circumference and specific mental abilities, such as fluid reasoning and processing speed, and found that the positive correlation here was even higher than for general intelligence itself.11 Further, the professors cited three studies which found that this correlation holds true within families as well as between families. In other words, intelligent individuals tend to have larger brains than their less intelligent relatives.12

In conclusion, it is clear that the size of one’s brain bears a strong correlation to one’s general intelligence as well as to the specific mental abilities which comprise it. Beyond that, the races of man differ in the average sizes of their brains in a way which roughly corresponds to their tested IQs. Finally, species differ in their average brain sizes as well, with these differences corresponding rather closely to their respective differences in intelligence. There is certainly more that goes into determining intelligence than just the size of the brain; its complexity is important too, along with many other biological and even environmental factors. Nevertheless, brain size is clearly crucial in some way, for more than a hundred years of research and observation have proven a positive correlation between it and intelligence.


1. A positive correlation in statistics means that when one variable increases, the other does too. Correlation does not always mean causation, but it does imply some kind of connection between the variables. This means that one has a fairly reliable predictive value for the other. In the case of the present study, the positive correlation between brain size and intelligence has been confirmed, so when one increases, we expect the other to become higher as well.

2. Lynn was Emeritus Professor of Psychology at the University of Ulster until 2018, when his title was revoked by the university following protests by its students’ union over the “racist” nature of his work. See, accessed August 6th, 2022.

3. There are a few outliers which I did not include on this list, such as the brown-capped capuchin, which has an EQ of 3.5 yet is less intelligent than the chimpanzee. However, the general trend can be seen. Richard Lynn, Race Differences in Intelligence: An Evolutionary Analysis, second ed. (Arlington, Virginia: Washington Summit Publishers, 2015), 266-67.

4. The Evolution of Human Nature. Quoted in William Gayley Simpson, Which Way Western Man?, second ed, (Hillsboro, WV: National Vanguard Books, 2003), 708.

5. 286-87.

6. Ibid., 216.

7. Vladimir Avdeyev, Raciology: The Science of the Hereditary Traits of Peoples, second ed., trans. Patrick Cloutier (Moscow: The Library of Racial Thinking, 2007), 159.

8. Lynn, 104-5, 160, 206-7.

9. Ibid., 285-87.

10. John R. Baker, Race, third ed. (Burlington, Iowa: Ostara Publications, 2016), 266.

11. J.P. Rushton and C. Davison Ankney, “The Evolution of Brain Size and Intelligence,” in Evolutionary Cognitive Neuroscience, ed. S. M. Platek, J. P. Keenan, and T. K. Shackelford (Cambridge: The MIT Press, 2007), 123-131.

12. Ibid., 132.

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17 August, 2022 1:42 pm

Great article, so informative! I learned so much. You made great use of the cited sources. Really enjoyed it, looking forward to your next article.

17 August, 2022 2:10 pm

I wonder if Asians really have a higher average IQ than Whites. Remember that Japan, the most advanced Asian country (and one that I respect), was still stuck with Medieval or at most, early modern-era technology until the late 1800s, when it rapidly modernised by adopting White technology.

Reply to  Joshua
17 August, 2022 10:43 pm

Great comment; maybe a subject for a future article!

Art Thief
Art Thief
Reply to  RCavallius
18 August, 2022 10:31 am

I don’t recall if it was NV or another source, but Asians – especially Chinese and Japanese- have high cheating rates on standardized tests as well as much more prep and coaching offered to them by their fellows. The subject of Japan could be countered with pointing out that there were specific political causes to their two hundred year stagnation during the Edo period which actively stifled innovation in all areas alongside their subsequent renaissance of innovation as well as the ongoing Chinese renaissance and the technology powerhouse that is Korea. …all of which, though, rely on White achievements to improve upon. I rather suspect that Asians really are that smart but that there is something in the psyche which we haven’t found a way to measure, let alone demonstrate… Read more »

Reply to  Art Thief
18 August, 2022 11:24 am

You’ve read about this matter, I see. Good job. Yes, I suspect you are on the right track here. East Asians also tend to have a lower verbal ability than Whites, and since verbal ability has the strongest correlation with g this could mean that even if they are actually scoring higher overall, their score is being lifted by their scores on nonverbal parts of the test, which gives them a higher tested IQ but not necessary a higher real life intelligence. We know that IQ is not a perfect measure of intelligence, so something is going on here. Nevertheless, I think it would be disingenuous to say that East Asians are not an advanced race. How they compare with us can be debated all day – and I think… Read more »

Joe Winters
Joe Winters
Reply to  Art Thief
19 August, 2022 9:16 pm

Northeast Asians have an intelligence that is not general but (like the jews) is very specialized. Europeans have a general intelligence which makes them equally good at everything. Asians have a tendency to conformity which is the enemy of creativity and innovation. This is not to say that the NE Asians can’t create or innovate in the right situation, but their tendency is to go along with the group, to keep their head down and not draw attention to themselves or their families. From the viewpoint of racial survival, this is an advantage, just as the individualism of the white man leaves him vulnerable to a cunning race like the jews. Whites need to stick together and not cut each other’s throats at the first opportunity. White people’s greatest enemy… Read more »

Reply to  Joshua
18 August, 2022 11:38 am
Art Thief
Art Thief
Reply to  RCavallius
18 August, 2022 9:48 pm

Articles and discussions on genetics, biology and intelligence (or, more aptly, racial achievement) are up there with those on art, culture and morality as my favorite subjects. Thank you, I will take a look at that one.

18 August, 2022 8:59 pm

Nice one RCavallius, I appreciate this kind of information.

Say, do you have anything on fight or flight/nervous system sollicitation, and the impact on brain functions?
I’m trying to fix my big brain after sustained chronic aggression by a human predator, I see the damage doesn’t have the same consequences than average IQ White men.
A remarkable inconvenience, as you probably have guessed.
Thanks if you do, keep on the good work.

19 August, 2022 12:00 am

Re “homo sapiens”

Yeah homo sapiens never miss a self-serving opportunity to proclaim their superior “intelligence” ….

Yet… at the core of homo sapiens is unwisdom (“invisible” madness) and so the human label of “wise”/sapiens is a complete collective delusion — study the scholarly essay The 2 Married Pink Elephants In The Historical Room

Once you understand that humans are “invisibly” insane you’ll UNDERSTAND (well, perhaps) why they perpetually come up with myths and lies about everything … including about themselves (their nature, their origins).

Caveat — only read the 2 pink elephant article if you’re GENUINELY interested in the truth and therefore “CAN handle the truth” …

Jim - National Alliance Staff
Jim - National Alliance Staff
Reply to  Virko
19 August, 2022 10:09 pm

A bit off topic, Mr. Virko, but vitamin C as a treatment for COVID has been looked at by a few governments health systems, non-governmental organizations, and of course, the National Alliance on our White biocentrism forum. We too are interested in the truth of things, as well as the overriding issue of White racial survival and placing our people on a better, progressive track as you’ll find here:

Mastering COVID requires that we master ourselves first. Consider joining us:

Thomas Jefferson
Thomas Jefferson
31 August, 2022 6:11 pm

IQ is just one factor that defines the value of a human society. We must also look at behavioural characteristics too. Blacks not only fail in the IQ stakes but they also fail to provide, in numbers needed to produce a functional society, law abiding citizens of good character. One only needs to look at the psychological data on blacks and whites of equivalent IQ, say 100 points. The difference in behaviour between the two racial groups of equivalent IQ is immense – providing another racial precipice that like the IQ one will never be bridged.