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> Alternatively, the decrease in brain size may simply reflect a decrease in mental storage of spatiotemporal data, due to the abandonment of hunting over large expanses of territory.

Worth noting that the modern peoples with the largest brain sizes are Siberian indigenous peoples followed by Inuit. Their visuospatial skills are anecdotally prodigious whereas their overall IQs are modest (low 90s).

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I'm not so sure about the Inuit. A study from northern Quebec shows that their IQ level is as good as or better than Europeans. That being said, I wonder about the term "age-appropriate U.S. norms" in that study.

Wright, S.C., D.M. Taylor, and K.M. Ruggiero. (1996). Examining the Potential for Academic Achievement among Inuit Children: Comparisons on the Raven Coloured Progressive Matrices. Journal of Cross-Cultural Psychology 27(6): 733-753. https://doi.org/10.1177/0022022196276006

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My cousins are Eskimos. They seem bright as any normal person. They could smell better than I could, and they swam like seals which seems odd given that swimming in Alaska ice pack probably isn't super great for survival.

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I've wondered about this. Wolves and coyotes are smarter than domestic dogs, but dogs appear smarter to us because they behave in ways we associate with intelligence in canines. We look at those tiny brained farmers and say, "smarter". But maybe they just had better conflict avoidance? Now, hunter gatherers are the losers. They were the guys that never could learn to do anything else and were pushed into the worst land, (except in the Americas). My thought is that the only place we can really compare intelligence between hunter gatherers and farmers is in the Americas. Yet here we have barriers at every level to test, compare, even to be certain of a group's historical activities.

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Mar 15·edited Mar 15Author

This is an important point. The brain is multidimensional, and certain aspects of mental capacity declined while others became more important. Hunter-gatherers are better than farmers, for instance, when it comes to orienting themselves in time and space, since farmers generally stay put in the same location. Hunter-gatherers may also have a greater capacity for memory, since literate cultures can keep information in external storage (on paper and now on electronic media).

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My grandfather could always spot where a buck would be bedded down by looking at the treeline. He could also walk up on wild deer without causing them to bolt. We made decent money by trapping coyotes. He knew exactly where a coyote would set its feet.

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You are clearly in denial about the nature of intelligence lol. And you clearly buy into romantic myths about Hunter Gatherers like many other Western people.

Border Collies and many other Domestic Dog breeds are smarter than any species of wild Canids. And there's zero biological evidence of cognitive decline with the transition to agriculture from foraging. Also, the which to agriculture happen before the last Ice Age, when the relative decline in cranial size among certain populations only happened when the Ice Age ended.

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I was raised by the first generation descendants of hunter gatherers. You seem to think that negritos today represent the entirety of HGs from 10k BC. Have you owned or raised coyotes or wolves?

I think it's entirely possible HGs as a group were less intelligent than farmers. I also believe it is entirely possible HGs 10k BC were just as intelligent. Intelligence is correlated with brain size. Today's stats mean nothing about 10k BC when people were just discovering whether millet or wheat makes better crops.

I know what the res produces, some have never had a high school graduate in years. I know what the current IQ is now. That doesn't address my suspicion that self control and 'meekness' as well as cooperation. We associate those qualities with IQ but they don't have to.

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I wasn't even thinking about the Negritos when commenting on Hunter Gatherers. I was thinking about groups like the Hadza and Paleolithic peoples.

Also, brain size only accounts for 30%-40% of intelligence, the rest largely comes down to neural interconnectivity and the number of genetic alleles linked to intelligence. And the very notion that brain size shrunk across thousands of years at all has been called into question by recent research.

Also, no scientists who study intelligence thinks traits like meekness, self control, cooperation, etc are necessarily signs of higher IQ, you are making a strawman. Those are heritable personality and behavioral traits unrelated to IQ that vary among individuals and populations as well as among different hunter gatherers tribes themselves

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Nuts.

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What if you control for the social complexity variable and just compare prehistoric hunter gatherers from cold climates with the same from warm climates? IE don’t Inuit, Siberians, Sami and such have higher IQs than equatorial hunter gatherers like sub-Saharan Africans and aboriginal Australians?

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Unfortunately, we don't have a lot of ancient DNA from hunter-gatherers in tropical regions. This is largely because DNA tends to degrade more rapidly in warm climates.

Nonetheless, we do have some aDNA from Cameroon and Tanzania. It would be interesting to see how it compares with the DNA of early European hunter-gatherers. https://doi.org/10.1038/s41586-022-04430-9

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Gracious that you cited me after reading a stray comment I made on the internet. Thanks!

Regarding your interest in sexual selection in human self-domestication, have you read Robert Bednarik's work? He puts forth a model where male preference for neonoteny drove the gracilization of human skeletons in the last 40,000 years. Book title: The Domestication of Humans (available on Library Genesis).

See also treatment of Bednarik's idea in James Thomas's dissertation Self-domestication and Language Evolution or the more recent paper Globularization and Domestication.

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Not Bednarik specifically, but I've come across that idea in the writings of many authors, notably Konrad Lorenz and Ashley Montagu.

P.S. I enjoyed reading your last blog post.

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Thanks! Would happily link any response/review

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When Villmoare and Grabowski (2022) reanalyzed the cranial data for the last 300,000 years, they found that brain size remained stable from 300,000 to 60,000 years ago. It then diversified, becoming larger in some populations and smaller in others. This was when modern humans were spreading out of Africa and into new environments in Eurasia. Unfortunately, Villmoare and Grabowski did not attempt a regional analysis of the last 30,000 years.

For the last 10,000 years, Hawks (2011) found a declining ratio of brain size to body size in ancestral Europeans and Chinese. But no decline was discernable for Nubians, the only non-Eurasian population for which we have a large cranial sample.

For more information:

https://evoandproud.blogspot.com/2022/11/recent-evolution-in-human-brain-size.html

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I saw this week response to Uber soy by Kevin Byrd and he didn't respond to for some reason could you respond to this I'm not an expert in the field please I'll quote it Uber soy I saw a response to you by Kevin Byrd can you respond to this

This is some embarrassing flailing. I document several misrepresentations and inaccuracies in your video. The claims about the cause of the Flynn effect decline and the relationship of g-loaded IQ subtests and culture were just two direct refutations. You seem very confused about the fact 84% of genes are expressed somewhere in the brain at some point during development. This has no implication for racial differences unless you can specifically identify expression differences between races and their relationship to IQ. This research has not and likely cannot be done and the genetic data I presented shows there is no evidence of substantial genetic differences between races for genes associated with intelligence when you correct for biases in GWAS engage with your references the whole time, and bring up studies that address the crucial weaknesses in your cited work. It's a literature review based on some of the latest genetic studies and on economic papers that correct for the shoddy statistical analyses used in much of the IQ literature. It isn't the "sociologist's fallacy" to show that accounting for these socioeconomic differences reduces the gaps since there is strong evidence and historical documentation that these socioeconomic differences between races are not genetic themselves and again no evidence from that genetics contributes to these racial gaps. Bringing up the Coleman report is irrelevant when I present papers from this decade (not half a century ago) showing that data from 4 million students pointing toward economic inequality and segregation as driving the majority of achievement test score gap in schools. You should update your references to the proper century. Now addressing the rest of your tantrum in order: 1. Yes, correlational research is weak and needs either experimental validation or more robust methods to infer causality. 2. They are fundamentally interactions, they are not separable as genetic or environmental and they show that phenotypes can change in different environments. 3. Laughing does not refute my own published researcher showing that genes associated with intelligence do not show the patterns that would be present if natural selection were acting to make Europeans more intelligent than Africans. 4. Your evidence for dysgenics relies on faulty genetic methods prone to false-positives and from researchers with no credibility or expertise. 5. The sibling study on the Flynn is precisely the kind of well-designed study that can distinguish genetic from environmental causes and it unambiguously supports environment and precludes genetic causes. 6. Fst between dog breeds are much larger than between human populations. The paper I cited references 3-5% for human races and 27% for dogs using comparable genetic markers. 7. The distinction between within- and between group heritability is a fundamental aspect of that statistical method. Also the data I presented did show school districts where there are no racial test score gaps, a closing racial test score gap for national standardized tests, and IQ tests which show no racial gap. have to once again stress that the "g" in g-factor is not referencing genetics. genetics and the g-factor are largely unrelated thing. Also, the study about education and gender inequality is not "unknown" and uses data from three well known large studies with representative samples sizes. 9. The Ritchie and Tucker-Drob paper does not show a fade-out effect from these education gains. At least read what you try and criticize. 10. I cited papers that controlled for income and wealth and they accounted for nearly the entire gap in academic performance. 11. That paper I cited is literally the main reference in your own review paper, along with a large single-cohort study of 18,000 people showing a correlation of 0.27, which the authors settle on as the most likely value

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"Autism has become more common since the last ice age."

In which of the studies should I look to read more about that?

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In the second one, by Davide Piffer and Emil Kirkegaard:

"Intriguingly, schizophrenia and autism demonstrated divergent temporal trends, aligning with the theory that these disorders embody opposite ends of the psychological spectrum (Crespi et al., 2010). Furthermore, their correlation with Years BP aligned with pleiotropic impacts on cognitive abilities, given that schizophrenia and autism present reciprocal genetic correlations to IQ."

"Autism exhibited a significant positive correlation with EA3 and EA4 (.59 and .68 respectively), contrasting with a substantial negative correlation with schizophrenia (−.83). This supports the

hypothesis that schizophrenia and autism are at different extremes of the psychological spectrum (Crespi & Badcock, 2008; Crespi et al., 2010), possibly representing divergent cognitive-behavioral adaptation strategies in socio-cultural environments. The positive link between autism and cognition corroborates previous findings."

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"Among the subsamples, Bronze Age Greeks showed the highest level of cognitive ability as measured by alleles associated with IQ, but this result was not replicated by alleles associated with EA."

The discrepancy between the educational attainment and IQ PGSs seems strange (I must admit I hardly understand the topic).

Moreover, surprised about the medieval Irish scoring so high on the IQ PGS, higher than all the other medieval Europeans. I had heard before that the medieval Irish monks were special or something but, obviously, one cannot make any inferences about Ireland as a whole from that. What does the fact that it is left-skewed tell us?

I'm also surprised by the relatively low score of medieval Germany, but I always did think they were lacking culturally until the early modern age. Aside from German epic poets like Wolfram Von Eschenbach and the Nibelungenlied, German literature doesn't really take off (dramatically) until the 18th century with Lessing, Kant, Goethe, etc. From the little I've read and what literary critics appear to value and pay attention to, Spanish, Italian, Portuguese, etc., literature are much more interesting until that point. I know that the political fragmentation of the Holy Roman Empire was not favorable, but still... The Minnesinger music is like chalk to my ears. Trecento, Troubadour music, and the like are much more pleasant to listen to.

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I, too, am puzzled by that finding. Michael Woodley of Menie looked at ancient DNA from Greek samples and found an increase in cognitive ability from the Neolithic to Mycenaean times, followed by a decrease between then and the present.

https://evoandproud.blogspot.com/2019/07/the-golden-age-of-intelligence.html

That study was never published because of the small sample size (n=1020.

Medieval Irish scoring high on IQ PGS? Where did you find that?

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It is remarkable that we have access to this information, and I wonder exactly how much we can find out. I wonder if the Sogdians were a particularly intelligent group (I would think so), if the ancient Hebrews were (the Bible is pretty remarkable + Wikipedia says the brother of Philo was perhaps the richest man in the Hellenistic world), if the Persians practiced endogamy to the extent that the Indians did (Gregory Cochran suspected that there's "serious genetic stratification" in Iran), etc. I wonder what the genetic history of the Parsis, the endogamous groups of India, Sayyids (can they back their ancestry?), Amerindians (Mesoamerican and Andean, in particular) looks like.

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I would love to see a study on the Parsis.

https://peterfrost.substack.com/p/the-parsis-and-gene-culture-coevolution

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Mar 16·edited Mar 16

The Sikhs, and especially the Jains, are two groups that also perform well socially and economically. The high socioeconomic status of Sikhs is not at all surprising when one considers the rational nature of their founder, Guru Nanak. The first converts were likely individuals who were both rational and empathetic. This is even more the case for the Jains, who, in my opinion, practice the most rationally ethical religion in history. This is taken to an extreme with Sallekhana, a suicide ritual through fasting.

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> This is taken to an extreme with Sallekhana, a suicide ritual through fasting.

Yeh, sounds totally rational.

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I wish I could access the paper.

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Mar 16·edited Mar 16

I have the same understanding of genetics as the Ancient Greeks, but the discrepancy between the relatively low scientific innovation and the high educational attainment polygenic scores (EA PGSs) of the Romans points to an interesting pattern. Perhaps a discrepancy between EA PGSs and IQ is correlated with certain types of innovation. From what I understand, East Asians perform even better academically than their high IQs would suggest (e.g., GPA, SAT scores), yet they significantly underperform in certain types of scientific and perhaps cultural innovation compared to what their scores might predict. Is it possible to compare the genes that contribute to educational attainment between East Asians and Europeans, or are their cognitive structures too different? If the same genes contribute, I would expect the difference between East Asian and European EA PGSs to be even greater than the IQ difference.

Another idea that comes to mind is that EA and innovation might be correlated with only certain subsections of IQ. If possible, it would be interesting to test for verbal, mathematical, etc. subtest scores of IQ in ancient populations via PGSs.

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Thanks! Galton vindicated:

"A significant divergence was noted in the sample of ancient

Greeks from the Bronze Age in the comparison between IQ and

EA. The Bronze Age Greeks, while displaying average scores on

EA, manifested the highest scores in IQ PGS. This result was

predicted based on their renowned cultural accomplishments and

is in agreement with the historical estimates by Galton (Galton,

1869)."

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Human brains did not shrink in size thousands of years ago:

https://neurosciencenews.com/evolution-brain-shrinkage-21195/

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The article is referring to a claim that brain size shrank 3,000 years ago. That claim is false, but there is good evidence that brain size decreased among Eurasians after the last ice ago, c. 12,000 years ago.

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This is another great and highly anticipated update to your regular posts Peter!

My first question is why did the Bronze Age Greeks show the highest level of cognitive ability as measured by alleles associated with IQ? What were the driving factors for this increase?

My second question that is the fact you've mentioned that in Western Europe, mean cognitive ability seems to have fall since the turn of the twentieth century. In your opinion will this trend continue for the next 50 to 100 years? Is there anything that can be done to reverse this decline? What would it take to raise intelligence to the same increases seen in the early medieval period?

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Farming was introduced into Europe from the southeast. So the Greeks were farmers for a longer time and were the first to develop writing and urban culture.

As for your second question, financial incentives aren't enough. We need to move the cultural norm toward pro-natalism and away from voluntary childlessness. Specifically, we should:

- create a review board for advertising to ensure that most images show intact families with at least 3-4 children.

- increase tax deductions for families with children

- ban "gender reassignment" of children. This is sterilization of people who are not mature enough to make such a drastic decision.

- follow the example of Israel. That country has raised the fertility of its population above replacement even in the case of secular high SES individuals.

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Mar 16·edited Mar 16

I strongly agree with the government taking a prescriptive approach to popular culture. Previously, I had uncritically admired transgressive art and, while I still enjoy it, I now view it as a signal of things going astray. To give an example: Euripides, Catullus, and Rimbaud, all worked at the peaks of their respective eras: the Golden Age of Athens, the Late Roman Republic, and fin-de-siècle France, respectively. Of course, what was transgressive back then was different from what is transgressive nowadays.

It's really difficult to enjoy movies and TV shows that portray socio-structural patterns which obviously do not reflect real life. It feels as though they are insulting my intelligence, yet it seems like millions uncritically take them at face value! Perhaps a decentralization of mass media will occur when ai tools become more available. This might allow people to consume media which aligns more closely with their innate predispositions. Of course, that is a double-edged sword because it might even further increase the polarization of society.

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That worries me a lot too. It's disturbing to think of the present as a slow death. My guess is that the genetic alteration of intelligence will keep at least some people from regressing too far down.

Personally, it sometimes feels like I was born at the very outset of the end of human history, as in, the end of regular humans. Whether it progresses or collapses, I no longer feel like I am a part of humanity. Programming, my career, is being taken over by advanced applied statistical models. But the real kicker is the genetic alteration of intelligence. It is very egotistical and selfish, but I always thought of that as the one thing which I had that was a tiny bit special, but now even that might be rendered trivial. It feels like dreams are impossible now. Yet, it is best to just stoically continue as before, and to enjoy what remains.

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Yes, even in my lifetime I have seen a definite dumbing down of popular culture. Plots are becoming simpler in movies. In newspapers and magazines, the writing is simpler, with shorter and less complex sentences. Verb tenses are becoming simpler. The simple past is replacing the pluperfect and the present perfect.

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