I prefer framing it as "new technology" rather than "shifting culture". Smarter people adapt better to new technologies and thus have more children. Culture doesn't just randomly change.
And once farming became widespread, people had a lot more time and resources to invent new technologies. Anyway good article.
Another very insightful and well-written article Peter. Coincidentally have you heard of this new paper, from last week, via the American Psychological Association on a hypothesis that modern East Asian populations inherited and maintained extensive psychosocial adaptations to arctic environments from ancestral Ancient Northern East Asian populations, which inhabited arctic and subarctic Northeast Eurasia around the Last Glacial Maximum period of the Late Pleistocene.
The main trust of this study is that "Arcticism" (living, surviving and evolving in extreme cold for generations) better explains the paleo-origins of general Educational Attainment psychology (not more recent rice farming collectivism) in East Asians, before adding on later Holocene individualism effects of pastoralism on Mongols/Tibetans, & collectivism effects of agriculture on Han Chinese, Japanese, Koreans -- leading to further local variation.
However the author takes the view of environmental influences on personality instead of IQ; because, personality is more predictive of life outcomes vs IQ, & so in aggregate, civilizational outcomes.
I will read it. I tend toward a middle-of-the-road position, i.e., cold, seasonal environments gave northern Eurasians a cognitive edge over other human groups. Specifically, they had to meet several cognitive demands that existed nowhere else during the last ice age (before 10,000 years ago):
- collect, process, and remember huge quantities of spatiotemporal data to track herds of wandering herbivores (e.g., reindeer), to predict their movements, and to find one’s way back to camp;
- monitor untended traps and snares to capture solitary animals, which were dispersed over a larger territory than in warmer environments and took too much time to hunt;
- make cold-resistant shelters and clothing;
- plan ahead to store fuel for winter and food for times of need.
Thus, after the last ice age, they were able to expand southward at the expense of temperate and even tropical populations. In some cases, like farming, the latter populations were the first to make a cultural advance, but this advance was subsequently taken over and better exploited by groups expanding out of northern Eurasia.
Nonetheless, cognitive evolution did not begin and end in northern Eurasia during the last ice age. It continued even into historic times, and most of that evolution took place in non-Arctic environments.
Interesting. I had been wondering when someone was going to run this analysis for East Asia.
Has anyone looked at changes in the percentage of runs of homozygosity over time in ancient samples? It would be interesting to see how inbreeding and outbreeding patterns have changed, especially since some in the HBD sphere ascribe a lot of significance to this in terms of driving differences in social behavior.
Ringbauer et al. (2021) found that runs of homozygosity are rare in DNA from antiquity. In relatively recent times, they tend to cluster in the Near East, North Africa, Central/South Asia, and South America:
"The rate of long ROH is substantially higher in the present-day Human Origins dataset; we inferred that 176 of 1941 modern individuals (9.1%, CI: 7.8–10.4%) have long ROH. In contrast to ancient data, several geographic clusters of long ROH are found, mainly in present-day Near East, North Africa, Central/South Asia, and South America. This signal was described previously and mirrors the estimated prevalence of cousin marriages"
Ringbauer, H., Novembre, J. & Steinrücken, M. Parental relatedness through time revealed by runs of homozygosity in ancient DNA. Nat Commun 12, 5425 (2021). https://doi.org/10.1038/s41467-021-25289-w
I'm skeptical of claims that inbreeding interferes with cognitive evolution. Before the 20th century, Ashkenazi Jews had high rates of inbreeding, yet their mean cognitive ability rose considerably during the late medieval/post-medieval period. The same is probably true for the Parsis.
Did Ashkenazi Jews actually have high rates of close inbreeding, in the sense of with fairly close relatives? Or just high enough endogamy overall to result in relatively low genetic diversity? My understanding is that the former is associated with long runs of homozygosity, the latter with high homozygosity overall, and that these two measures are not necessarily strongly correlated. Like for instance, Finns might be more genetically homogenous than Arabs due to a Finnish population bottleneck, and Arabs having had admixture with other populations in the region. But since Arabs have higher rates of cousin marriage than Finns, they would have more runs of homozygosity even if the population has less homozygosity overall.
It also seems like you could get selection operating in an inbred population in the opposite direction to the effects of inbreeding depression, as long as the selective pressures were strong enough. Inbreeding decreases height as well, but if you created a closed population of NBA and WNBA players, isolated them, and put them under a strong selective pressure for height, I expect they'd end up quite tall despite the inbreeding. I'm not sure if the same inbreeding depression of size operates in dogs, but there are some breeds of dogs that have been selected for a large size despite a small breeding population.
It was both. Ashkenazi Jews have high homozygosity because they are descended from a small founder group. Any two individuals within this community share about as much DNA as fourth or fifth cousins.
But this community also had, historically, a high rate of cousin marriage. This was partly for the reason that Alan Perlo cites (see below). The range of possible spouses was relatively narrow, so the chances of marrying a cousin were greater than in the non-Jewish community.
But there also seems to have been a preference for cousin marriages in the sense that kin networks were valuable for trading relationships. "Repeated marriages between close kin or a second marriage into the same family helped cement reliable relationships" (Sabean, 2002, p. 101)
David Sabean cites the example of the Rothschild family:
"The Rothschild family constitutes a dramatic example of the development. Of
fifty-six marriages entered into by descendants of Meyer Amschel in the nineteenth century, precisely half were between first cousins or uncles and nieces." (Sabean, 2002, p. 95)
Source:
Sabean, David. "Kinship and Prohibited Marriages in Baroque Germany: Divergent Strategies among Jewish and Christian Populations." Leo Baeck Institute Yearbook 47 (2002): 91-103.
Yes I was not fully aware of this Rothschild example, but it fits with ancient Middle Eastern tradition. I think a good working model of inbreeding types is:
*Worldwide rural inbreeding, practiced because of a genuine lack of choices and a general ignorance, from time immemorial or at least a decently long time
*Elite inbreeding, which was done since Ancient Egypt and the Anatolian Neolithic farmers in Europe and in some ways was/ still is practiced in some groups
*Islamic inbreeding, which extended the elite modus operandi to larger swathes of the population which had the aspiration of greater social prominence. It's key to remember that Islam is seen as a prestigious new social system in more backward areas like West Africa, and perhaps also the Indian subcontinent and North Africa a longer time ago
Many Islamic practices have their origins in elite behavioral norms, which were seen as desirable and thus extended by Islam to the entire population. Like Christianity, Islam did not so much create new norms as promote existing ones more effectively.
An analogy could be made with perfume. Muslims are not required to perfume their bodies and homes, but this practice is seen as good within Islamic culture, probably because of its initial association with elite behavior. It has thus become common throughout the Islamic world. In the same way, not all Muslim groups practice cousin marriage, but this practice seems to have been encouraged by Islam, probably because it was something that elite individuals did.
Napoleon Chagnon writes lots about cross marriages in tribal societies. I think he said it was in order to create intense coalitions by creating genetic bonds between families. Or perhaps I’m thinking also of Laura Betzig’s work. She was saying that in tribes, the more relations you had, the more you were able to swing disputes over power and resources in your own favour (and this was quite central to her PhD thesis). So there may have been a local judge who was supposed to be impartial. But basically, if you were in dispute with another person and you have more family relations, then the judge will not be able to oppose you. So she was saying it was crucial to gaining familial power in tribes. So could this kind of allegiance building also be playing out in larger communities whereby elites can gain greater power and solidarity amongst themselves if they are related through family marriage? People will be more likely to come to your aid in disputes and local wars if they are related?
Ashkenazi did not necessarily encourage cousin marriage in the diaspora, but since keep it within the tribe was of paramount importance and they frequently lived in small communities, often first or second cousins were considered good matches. Other Levantine groups like Assyrians and Maronites do this in the diaspora, at least until the generations born in the 1970s in Mexico for example. So AJs probably have more runs of homozygosity and overall homozygosity than say non-Finn Europeans or very rural European exceptions.
I agree with your last sentences. Inbreeding among elite groups can have a higher rate of diseased offspring, but also of offspring with a "double-copy" of beneficial traits. That's probably one of the reasons it became a traditional practice, though of course non-elite groups in the regions mentioned above also practice cousin marriage.
Okay, I have a question for you. You may well not have an answer for me. But if you don't have an answer, I really hope that this question might pique your interest and you might start looking out for a information regarding this question.
I've been a music teacher for 25 years. When I started teaching piano, I was astonished by the first East Asian pupil I taught (age 10). Unlike most pupils She had memorised her pieces and was playing them to perfection at a far superior level than any of my other pupils. Having now taught for many more years, I've been astonished to discover that EVERY SINGLE East Asian pupil I've ever taught has a similar ability.
Now it's important to differentiate something here. I've come to see reading music as a different ability to memorising music. Often people who can read really well- (And some people can read at an astonishing level Almost playing a concert level piece from sight the first time they've seen it) Have no ability to memorise. I've come to think that perhaps memorising music is a right brain ability and comes from chunking music into spatial patterns that can be memorised. However, reading music is a READING ability much like reading a book and has little to do with musical visual memory. It seems to me like people who can read books at a super speed. They're just processing the written information at an amazingly fast pace.
In any event, it's primarily the musical memory and being able to chunk music into spatial patterns that East Asians appear to always have. I'd say in comparison, amongst Western pupils, 10% are exceptional and 30% quite good At memorising in this manner.
I've noticed most western pupils who have the same memorising ability as East Asians tend to have ADHD. Quite why people with ADHD and East Asians would both have the same ability as beyond me.
Anyway, would love to know if you have any thoughts on this! And if not, I'd love you to lookout for anything you can pick up regarding this as you meander through your reading.
As someone who's taught for 25 years, this phenomenon is quite frankly remarkable. And as I say it's 100% of East Asians not even high percentage: 100% in my experience.
Thanks so much for all the amazing work You're making such great efforts to share with us. It means so much!
Well this is very interesting. So firstly I'm saying ADHD people have this remarkable spatial ability. I'm talking about where they can visually chunk music and build a map of a piece and memorise the music.
They also have some problems when playing, but these are completely eclipsed by their remarkable musical ability to memorise. So I've found they tend to play a little messily, they're not perfectionist. They really enjoy playing because their ability is so strong, but they're not trying to perfect things so there's lots of little errors. It's a sort of rough and ready playing. But this is where having a tutor really helps. Because my job is to try and correct these errors. I'm pretty sure that the same dynamic occurs with sportsman and their coaches. I imagine elite sportsmen tend to have ADHD as well.
So the really notable thing about people with ADHD is they cannot slow down their playing. I used to think they just didn't want to, but I now think it's linked to the frontal lobes. They're not actually able to do it when I ask them to do it. The only way I can get them to slow down is by actually counting out loud and making them play to my counting so they can hear what it sounds like to play slower; or making them play to a metronome and then they can hear what it sounds like slower and match that (And there's actually been some research showing playing to a metronome helps people with ADHD). It seems almost impossible to get them to do it unless I count or put a metronome on. But this comes back to the same thing: they do well with coaches who can help them perfect their untamed and unfocused, but yet remarkable ability.
Anyway, please do look out for anything you can find about East Asians and this remarkable ability to memorise music. As I say, I think it's a right brain thing and I think it's related to prenatal testosterone enhancing right brain abilities. But I'm not sure why that would be the case for East Asians.
Oh and many of the best musicians who have this memorising ability have a really low finger ratio I have found. Sometimes 0.92
This study concluded that East Asians have better pitch memory for cultural (rather than genetic) reasons.
ABSOLUTE PITCH (AP) IS THE ABILITY TO IDENTIFY OR produce a musical note in isolation. As traditionally defined, AP requires accurate pitch memory as well as knowledge of note names. The incidence of AP is higher in Asia than it is in North America. We used a task with no naming requirements to examine pitch memory among Canadian 9- to 12-year-olds of Asian (Chinese) or non-Asian (European) heritage. On each trial, children heard two versions of a 5-s excerpt from a familiar recording, one of which was shifted upward or downward in pitch. They were asked to identify the excerpt at the original pitch. The groups performed comparably, and knowledge of a tone language did not affect performance. Nonetheless, Asians performed better on a test of academic achievement. These results provide no support for the contribution of genetics or tone-language use to cross-cultural differences in pitch memory.
I prefer framing it as "new technology" rather than "shifting culture". Smarter people adapt better to new technologies and thus have more children. Culture doesn't just randomly change.
And once farming became widespread, people had a lot more time and resources to invent new technologies. Anyway good article.
Another very insightful and well-written article Peter. Coincidentally have you heard of this new paper, from last week, via the American Psychological Association on a hypothesis that modern East Asian populations inherited and maintained extensive psychosocial adaptations to arctic environments from ancestral Ancient Northern East Asian populations, which inhabited arctic and subarctic Northeast Eurasia around the Last Glacial Maximum period of the Late Pleistocene.
The main trust of this study is that "Arcticism" (living, surviving and evolving in extreme cold for generations) better explains the paleo-origins of general Educational Attainment psychology (not more recent rice farming collectivism) in East Asians, before adding on later Holocene individualism effects of pastoralism on Mongols/Tibetans, & collectivism effects of agriculture on Han Chinese, Japanese, Koreans -- leading to further local variation.
However the author takes the view of environmental influences on personality instead of IQ; because, personality is more predictive of life outcomes vs IQ, & so in aggregate, civilizational outcomes.
Paper: https://psycnet.apa.org/fulltext/2025-88410-001.html
I will read it. I tend toward a middle-of-the-road position, i.e., cold, seasonal environments gave northern Eurasians a cognitive edge over other human groups. Specifically, they had to meet several cognitive demands that existed nowhere else during the last ice age (before 10,000 years ago):
- collect, process, and remember huge quantities of spatiotemporal data to track herds of wandering herbivores (e.g., reindeer), to predict their movements, and to find one’s way back to camp;
- monitor untended traps and snares to capture solitary animals, which were dispersed over a larger territory than in warmer environments and took too much time to hunt;
- make cold-resistant shelters and clothing;
- plan ahead to store fuel for winter and food for times of need.
Thus, after the last ice age, they were able to expand southward at the expense of temperate and even tropical populations. In some cases, like farming, the latter populations were the first to make a cultural advance, but this advance was subsequently taken over and better exploited by groups expanding out of northern Eurasia.
Nonetheless, cognitive evolution did not begin and end in northern Eurasia during the last ice age. It continued even into historic times, and most of that evolution took place in non-Arctic environments.
Interesting. I had been wondering when someone was going to run this analysis for East Asia.
Has anyone looked at changes in the percentage of runs of homozygosity over time in ancient samples? It would be interesting to see how inbreeding and outbreeding patterns have changed, especially since some in the HBD sphere ascribe a lot of significance to this in terms of driving differences in social behavior.
Ringbauer et al. (2021) found that runs of homozygosity are rare in DNA from antiquity. In relatively recent times, they tend to cluster in the Near East, North Africa, Central/South Asia, and South America:
"The rate of long ROH is substantially higher in the present-day Human Origins dataset; we inferred that 176 of 1941 modern individuals (9.1%, CI: 7.8–10.4%) have long ROH. In contrast to ancient data, several geographic clusters of long ROH are found, mainly in present-day Near East, North Africa, Central/South Asia, and South America. This signal was described previously and mirrors the estimated prevalence of cousin marriages"
Ringbauer, H., Novembre, J. & Steinrücken, M. Parental relatedness through time revealed by runs of homozygosity in ancient DNA. Nat Commun 12, 5425 (2021). https://doi.org/10.1038/s41467-021-25289-w
I'm skeptical of claims that inbreeding interferes with cognitive evolution. Before the 20th century, Ashkenazi Jews had high rates of inbreeding, yet their mean cognitive ability rose considerably during the late medieval/post-medieval period. The same is probably true for the Parsis.
Thanks for sharing the paper.
Did Ashkenazi Jews actually have high rates of close inbreeding, in the sense of with fairly close relatives? Or just high enough endogamy overall to result in relatively low genetic diversity? My understanding is that the former is associated with long runs of homozygosity, the latter with high homozygosity overall, and that these two measures are not necessarily strongly correlated. Like for instance, Finns might be more genetically homogenous than Arabs due to a Finnish population bottleneck, and Arabs having had admixture with other populations in the region. But since Arabs have higher rates of cousin marriage than Finns, they would have more runs of homozygosity even if the population has less homozygosity overall.
It also seems like you could get selection operating in an inbred population in the opposite direction to the effects of inbreeding depression, as long as the selective pressures were strong enough. Inbreeding decreases height as well, but if you created a closed population of NBA and WNBA players, isolated them, and put them under a strong selective pressure for height, I expect they'd end up quite tall despite the inbreeding. I'm not sure if the same inbreeding depression of size operates in dogs, but there are some breeds of dogs that have been selected for a large size despite a small breeding population.
As always, curious to hear your thoughts!
It was both. Ashkenazi Jews have high homozygosity because they are descended from a small founder group. Any two individuals within this community share about as much DNA as fourth or fifth cousins.
But this community also had, historically, a high rate of cousin marriage. This was partly for the reason that Alan Perlo cites (see below). The range of possible spouses was relatively narrow, so the chances of marrying a cousin were greater than in the non-Jewish community.
But there also seems to have been a preference for cousin marriages in the sense that kin networks were valuable for trading relationships. "Repeated marriages between close kin or a second marriage into the same family helped cement reliable relationships" (Sabean, 2002, p. 101)
David Sabean cites the example of the Rothschild family:
"The Rothschild family constitutes a dramatic example of the development. Of
fifty-six marriages entered into by descendants of Meyer Amschel in the nineteenth century, precisely half were between first cousins or uncles and nieces." (Sabean, 2002, p. 95)
Source:
Sabean, David. "Kinship and Prohibited Marriages in Baroque Germany: Divergent Strategies among Jewish and Christian Populations." Leo Baeck Institute Yearbook 47 (2002): 91-103.
Yes I was not fully aware of this Rothschild example, but it fits with ancient Middle Eastern tradition. I think a good working model of inbreeding types is:
*Worldwide rural inbreeding, practiced because of a genuine lack of choices and a general ignorance, from time immemorial or at least a decently long time
*Elite inbreeding, which was done since Ancient Egypt and the Anatolian Neolithic farmers in Europe and in some ways was/ still is practiced in some groups
*Islamic inbreeding, which extended the elite modus operandi to larger swathes of the population which had the aspiration of greater social prominence. It's key to remember that Islam is seen as a prestigious new social system in more backward areas like West Africa, and perhaps also the Indian subcontinent and North Africa a longer time ago
Many Islamic practices have their origins in elite behavioral norms, which were seen as desirable and thus extended by Islam to the entire population. Like Christianity, Islam did not so much create new norms as promote existing ones more effectively.
An analogy could be made with perfume. Muslims are not required to perfume their bodies and homes, but this practice is seen as good within Islamic culture, probably because of its initial association with elite behavior. It has thus become common throughout the Islamic world. In the same way, not all Muslim groups practice cousin marriage, but this practice seems to have been encouraged by Islam, probably because it was something that elite individuals did.
Napoleon Chagnon writes lots about cross marriages in tribal societies. I think he said it was in order to create intense coalitions by creating genetic bonds between families. Or perhaps I’m thinking also of Laura Betzig’s work. She was saying that in tribes, the more relations you had, the more you were able to swing disputes over power and resources in your own favour (and this was quite central to her PhD thesis). So there may have been a local judge who was supposed to be impartial. But basically, if you were in dispute with another person and you have more family relations, then the judge will not be able to oppose you. So she was saying it was crucial to gaining familial power in tribes. So could this kind of allegiance building also be playing out in larger communities whereby elites can gain greater power and solidarity amongst themselves if they are related through family marriage? People will be more likely to come to your aid in disputes and local wars if they are related?
Ashkenazi did not necessarily encourage cousin marriage in the diaspora, but since keep it within the tribe was of paramount importance and they frequently lived in small communities, often first or second cousins were considered good matches. Other Levantine groups like Assyrians and Maronites do this in the diaspora, at least until the generations born in the 1970s in Mexico for example. So AJs probably have more runs of homozygosity and overall homozygosity than say non-Finn Europeans or very rural European exceptions.
I agree with your last sentences. Inbreeding among elite groups can have a higher rate of diseased offspring, but also of offspring with a "double-copy" of beneficial traits. That's probably one of the reasons it became a traditional practice, though of course non-elite groups in the regions mentioned above also practice cousin marriage.
Hi Peter. Awesome post as always!
Okay, I have a question for you. You may well not have an answer for me. But if you don't have an answer, I really hope that this question might pique your interest and you might start looking out for a information regarding this question.
I've been a music teacher for 25 years. When I started teaching piano, I was astonished by the first East Asian pupil I taught (age 10). Unlike most pupils She had memorised her pieces and was playing them to perfection at a far superior level than any of my other pupils. Having now taught for many more years, I've been astonished to discover that EVERY SINGLE East Asian pupil I've ever taught has a similar ability.
Now it's important to differentiate something here. I've come to see reading music as a different ability to memorising music. Often people who can read really well- (And some people can read at an astonishing level Almost playing a concert level piece from sight the first time they've seen it) Have no ability to memorise. I've come to think that perhaps memorising music is a right brain ability and comes from chunking music into spatial patterns that can be memorised. However, reading music is a READING ability much like reading a book and has little to do with musical visual memory. It seems to me like people who can read books at a super speed. They're just processing the written information at an amazingly fast pace.
In any event, it's primarily the musical memory and being able to chunk music into spatial patterns that East Asians appear to always have. I'd say in comparison, amongst Western pupils, 10% are exceptional and 30% quite good At memorising in this manner.
I've noticed most western pupils who have the same memorising ability as East Asians tend to have ADHD. Quite why people with ADHD and East Asians would both have the same ability as beyond me.
Anyway, would love to know if you have any thoughts on this! And if not, I'd love you to lookout for anything you can pick up regarding this as you meander through your reading.
As someone who's taught for 25 years, this phenomenon is quite frankly remarkable. And as I say it's 100% of East Asians not even high percentage: 100% in my experience.
Thanks so much for all the amazing work You're making such great efforts to share with us. It means so much!
Phil
I'm a bit confused. Wouldn't ADHD make it difficult to focus on a particular musical piece? A recent study recommends musical training as a form of therapy for people with ADHD: https://link.springer.com/article/10.1007/s00426-024-02048-2
Well this is very interesting. So firstly I'm saying ADHD people have this remarkable spatial ability. I'm talking about where they can visually chunk music and build a map of a piece and memorise the music.
They also have some problems when playing, but these are completely eclipsed by their remarkable musical ability to memorise. So I've found they tend to play a little messily, they're not perfectionist. They really enjoy playing because their ability is so strong, but they're not trying to perfect things so there's lots of little errors. It's a sort of rough and ready playing. But this is where having a tutor really helps. Because my job is to try and correct these errors. I'm pretty sure that the same dynamic occurs with sportsman and their coaches. I imagine elite sportsmen tend to have ADHD as well.
So the really notable thing about people with ADHD is they cannot slow down their playing. I used to think they just didn't want to, but I now think it's linked to the frontal lobes. They're not actually able to do it when I ask them to do it. The only way I can get them to slow down is by actually counting out loud and making them play to my counting so they can hear what it sounds like to play slower; or making them play to a metronome and then they can hear what it sounds like slower and match that (And there's actually been some research showing playing to a metronome helps people with ADHD). It seems almost impossible to get them to do it unless I count or put a metronome on. But this comes back to the same thing: they do well with coaches who can help them perfect their untamed and unfocused, but yet remarkable ability.
Anyway, please do look out for anything you can find about East Asians and this remarkable ability to memorise music. As I say, I think it's a right brain thing and I think it's related to prenatal testosterone enhancing right brain abilities. But I'm not sure why that would be the case for East Asians.
Oh and many of the best musicians who have this memorising ability have a really low finger ratio I have found. Sometimes 0.92
https://pmc.ncbi.nlm.nih.gov/articles/PMC5890222
This study concluded that East Asians have better pitch memory for cultural (rather than genetic) reasons.
ABSOLUTE PITCH (AP) IS THE ABILITY TO IDENTIFY OR produce a musical note in isolation. As traditionally defined, AP requires accurate pitch memory as well as knowledge of note names. The incidence of AP is higher in Asia than it is in North America. We used a task with no naming requirements to examine pitch memory among Canadian 9- to 12-year-olds of Asian (Chinese) or non-Asian (European) heritage. On each trial, children heard two versions of a 5-s excerpt from a familiar recording, one of which was shifted upward or downward in pitch. They were asked to identify the excerpt at the original pitch. The groups performed comparably, and knowledge of a tone language did not affect performance. Nonetheless, Asians performed better on a test of academic achievement. These results provide no support for the contribution of genetics or tone-language use to cross-cultural differences in pitch memory.
https://doi.org/10.1525/mp.2008.25.3.241