Same reason that girls score the same or better than boys at 12-13 before boys begin doing better in adulthood. People gain in intelligence from undergoing puberty, so the people who go through puberty earlier will be more intelligent *at the time* even if they ultimately end up dumber in adulthood. I don't see any mention in these papers of when the age of testing happened.
Well, try to find a study with IQs measured in adulthood and menarche/puberty measures at in childhood. I see there's a bunch of GWASs on this. Try these for a start:
The methods sections mentioned the ages. 16 for the 1st study, 12-17 for the 2nd study, 11-15 for the 3rd study. I had the same thought that this could be causing the differences. In the 1st study, almost everyone should have completed puberty by age 16, but since GCSEs are based on previous coursework so much, it seems plausible that having gone through that coursework at a higher level of maturation (and intelligence) could result in a higher score on the exam at the end. For the other two, I think the inclusion of kids as young as 12 or 11 makes them less informative.
Anecdotally, I was a pretty early developer and noticed my academic ability relative to my classmates spike at age 12 (male). After that I still became smarter, but relative to my peers, my intelligence peaked at age 12.
Phil Rushton wanted to create a unified theory that could explain variation in intelligence, sexual maturation, and reproductive strategy for all human populations. In my opinion, he was too ambitious. Different human populations have followed different evolutionary trajectories in different natural and cultural environments. It's naïve to think that one can explain all human variation with a single theory — other than Darwin's theory of evolution by natural selection.
Yes, early sexual maturation and lower cognitive ability generally characterize the highly polygynous farming populations that originated in West Africa and later spread over most of the continent. But those two characteristics are not inevitably associated with each other — even within Africa. The Igbo were able to specialize in trade (because of their position at the Niger's mouth) and thus underwent selection for higher cognitive ability. I wouldn't be surprised if they still show a stronger propensity for polygyny and an earlier age of sexual maturation.
In short, there is a general association between higher cognitive ability, higher age of sexual maturation, and lower propensity for polygyny. But it seems to be a very distal association that is mediated by other factors, particularly the degree of female food autonomy. If women cannot feed themselves and their children without male assistance, they will abandon food gathering and specialize in activities with a higher level of cognitive input, like shelter building, garment making, meat processing, and use of kilns for metallurgy. This was notably the case with the populations of northern Eurasia.
Unfortunately not yet. This should be a research priority.
Most people, and Americans in particular, see the issue of IQ differences through the lens of the American historical experience, i.e., slavery and Jim Crow. It is important to show that these differences are ubiquitous — human populations normally differ in mean cognitive ability because people in different cultures have to adapt to different cognitive demands.
Above all, it is important to show that these population differences can arise over relatively short time scales, even between populations that are not normally considered to be "races" or even "ethnic groups."
Perhaps it is due to better nutrition (parents giving healthy food) and/or better adaptation to modern nutrition (grains etc). One of the largest modern selective forces is adaptation to modern diet. Poor childhood health/nutrition can delay puberty, retard academic performance and harm adult intelligence.
Puberty/sexual maturity means that one is suddenly able to procreate, and hence rewires the brain and hormones somewhat to be able to care for offspring, then I think it is not unreasonable to think that early sexual maturity has some (limited) advantages in IQ when measured before adulthood.
Academic achievement is often dependant on selfregulation, ability to plan ahead, impulsivity and other factors that comes (sometimes) with maturity. I blame it on "the relative age effect".
When it comes to height and shoulder width (for boys) my anecdotal evidence runs counter to the first qoute. Typically larger individuals takes longer to mature, sea lions being one example that comes to mind. Myself and my two sons spent f***ing forever in puberty before growing into our 2m bodies, as did their (and my) tall friends, while the smaller friends reached sexual maturity "over night" and "killed it" in sports and academics the next 2-4 years before being left in the dust when the others were fully grown.
If we could find cases of either dumb early maturers or academically high achieving late maturers, what does it imply for the fate of both theories, Rushton's and Terman's? Of course, not in terms of average patterns (which are often marginal anyways) found in normative studies, but in terms of explanatory mechanism. One single contradictory case (not to mention many) would be enough to invalidate any explanatory model that posits a direct relationship between comparative rate of maturation and cognitive abilities.
My perception of what might explain this is that testosterone is known to boost “spatial intelligence” and explains why boys perform slightly better in math.
There’s also research that prescribing anabolic testosterone to middle aged men increases their spatial intelligence on the Benton line orientation test.
Early puberty and tanner scale should be expected to boost intelligence and academics particularly in math.
I actually had a mustache in elementary school at age 10 and got referred to the gifted program for my scores in math assessments which were above average.
It doesn't really contradict Rushton's theory, the difference might be environmental or that ontogenesis isn't strictly determinate (how do we get 4% gay men even if any genes would be selected out?).
Should be also checked with puberty blockers or puberty accelerators.
Seems a fairly simple explanation would be that within the same gene pool better nutrition leads to a faster maturation, and thus a better outcome. But evolutionarily, there's a trade off between length of time maturing and eventual intelligence. Whatever spot that trade-off has arrived at given your genes, the overall process is sped up by better nutrition.
Sexual maturation is hormonal driven. Females mature earlier than males and black Africans have the highest level of sex hormones present. What are the differences between the intelligence of the genders across all races at the same biological age?Does the ratio of the two sex hormones between the different races vary?This may sound like it's going nowhere but in the context looking for clues as it were that it could help.
If I recall correctly, Ed Dutton has described geniuses as “intelligent r-strategists.” Just speculating, but maybe this assertion has more to it than the comparison first suggested?
As I think about it, the idea doesn’t seem totally apt, but it could have some points of merit. Maybe people with outlier-high intelligence are less constrained by the resource limitations in K-selected environments than the general population of such environments?
Again, this is mere speculation and likely doesn’t map onto reality in any clean way.
Easy explanation:
Same reason that girls score the same or better than boys at 12-13 before boys begin doing better in adulthood. People gain in intelligence from undergoing puberty, so the people who go through puberty earlier will be more intelligent *at the time* even if they ultimately end up dumber in adulthood. I don't see any mention in these papers of when the age of testing happened.
Well, try to find a study with IQs measured in adulthood and menarche/puberty measures at in childhood. I see there's a bunch of GWASs on this. Try these for a start:
https://pubmed.ncbi.nlm.nih.gov/28785901/ https://bmcmedicine.biomedcentral.com/articles/10.1186/s12916-020-01515-y https://pubmed.ncbi.nlm.nih.gov/32028806/
It doesn't appear that later puberty is good, even when looking at adult outcomes.
The methods sections mentioned the ages. 16 for the 1st study, 12-17 for the 2nd study, 11-15 for the 3rd study. I had the same thought that this could be causing the differences. In the 1st study, almost everyone should have completed puberty by age 16, but since GCSEs are based on previous coursework so much, it seems plausible that having gone through that coursework at a higher level of maturation (and intelligence) could result in a higher score on the exam at the end. For the other two, I think the inclusion of kids as young as 12 or 11 makes them less informative.
Anecdotally, I was a pretty early developer and noticed my academic ability relative to my classmates spike at age 12 (male). After that I still became smarter, but relative to my peers, my intelligence peaked at age 12.
So partition a time series into discrete units with some rate of variable elapsed unit of development per genetic potential unit.
Phil Rushton wanted to create a unified theory that could explain variation in intelligence, sexual maturation, and reproductive strategy for all human populations. In my opinion, he was too ambitious. Different human populations have followed different evolutionary trajectories in different natural and cultural environments. It's naïve to think that one can explain all human variation with a single theory — other than Darwin's theory of evolution by natural selection.
Yes, early sexual maturation and lower cognitive ability generally characterize the highly polygynous farming populations that originated in West Africa and later spread over most of the continent. But those two characteristics are not inevitably associated with each other — even within Africa. The Igbo were able to specialize in trade (because of their position at the Niger's mouth) and thus underwent selection for higher cognitive ability. I wouldn't be surprised if they still show a stronger propensity for polygyny and an earlier age of sexual maturation.
In short, there is a general association between higher cognitive ability, higher age of sexual maturation, and lower propensity for polygyny. But it seems to be a very distal association that is mediated by other factors, particularly the degree of female food autonomy. If women cannot feed themselves and their children without male assistance, they will abandon food gathering and specialize in activities with a higher level of cognitive input, like shelter building, garment making, meat processing, and use of kilns for metallurgy. This was notably the case with the populations of northern Eurasia.
https://evoandproud.blogspot.com/2014/01/the-first-industrial-revolution.html
I wonder if someone calculated Igbo IQ PGS.
>I wouldn't be surprised if they still show a stronger propensity for polygyny and an earlier age of sexual maturation.
They probably have earlier puberty than Europeans but later than other their African neighbours
Unfortunately not yet. This should be a research priority.
Most people, and Americans in particular, see the issue of IQ differences through the lens of the American historical experience, i.e., slavery and Jim Crow. It is important to show that these differences are ubiquitous — human populations normally differ in mean cognitive ability because people in different cultures have to adapt to different cognitive demands.
Above all, it is important to show that these population differences can arise over relatively short time scales, even between populations that are not normally considered to be "races" or even "ethnic groups."
Perhaps it is due to better nutrition (parents giving healthy food) and/or better adaptation to modern nutrition (grains etc). One of the largest modern selective forces is adaptation to modern diet. Poor childhood health/nutrition can delay puberty, retard academic performance and harm adult intelligence.
Puberty/sexual maturity means that one is suddenly able to procreate, and hence rewires the brain and hormones somewhat to be able to care for offspring, then I think it is not unreasonable to think that early sexual maturity has some (limited) advantages in IQ when measured before adulthood.
Academic achievement is often dependant on selfregulation, ability to plan ahead, impulsivity and other factors that comes (sometimes) with maturity. I blame it on "the relative age effect".
When it comes to height and shoulder width (for boys) my anecdotal evidence runs counter to the first qoute. Typically larger individuals takes longer to mature, sea lions being one example that comes to mind. Myself and my two sons spent f***ing forever in puberty before growing into our 2m bodies, as did their (and my) tall friends, while the smaller friends reached sexual maturity "over night" and "killed it" in sports and academics the next 2-4 years before being left in the dust when the others were fully grown.
If you're at all familiar with girls' sports it's very obvious Hispanic girls hit puberty a couple of years before White girls.
Just want to keep 3rd world out of my country. The only stat that matters
If we could find cases of either dumb early maturers or academically high achieving late maturers, what does it imply for the fate of both theories, Rushton's and Terman's? Of course, not in terms of average patterns (which are often marginal anyways) found in normative studies, but in terms of explanatory mechanism. One single contradictory case (not to mention many) would be enough to invalidate any explanatory model that posits a direct relationship between comparative rate of maturation and cognitive abilities.
My perception of what might explain this is that testosterone is known to boost “spatial intelligence” and explains why boys perform slightly better in math.
There’s also research that prescribing anabolic testosterone to middle aged men increases their spatial intelligence on the Benton line orientation test.
Early puberty and tanner scale should be expected to boost intelligence and academics particularly in math.
I actually had a mustache in elementary school at age 10 and got referred to the gifted program for my scores in math assessments which were above average.
It doesn't really contradict Rushton's theory, the difference might be environmental or that ontogenesis isn't strictly determinate (how do we get 4% gay men even if any genes would be selected out?).
Should be also checked with puberty blockers or puberty accelerators.
Seems a fairly simple explanation would be that within the same gene pool better nutrition leads to a faster maturation, and thus a better outcome. But evolutionarily, there's a trade off between length of time maturing and eventual intelligence. Whatever spot that trade-off has arrived at given your genes, the overall process is sped up by better nutrition.
Okay, Rushton's model doesn't work for everything.
But it works very well for racial differences.
this is the main.
furthermore, it was not designed to predict outcomes between individuals of similar races.
Sexual maturation is hormonal driven. Females mature earlier than males and black Africans have the highest level of sex hormones present. What are the differences between the intelligence of the genders across all races at the same biological age?Does the ratio of the two sex hormones between the different races vary?This may sound like it's going nowhere but in the context looking for clues as it were that it could help.
Just a basic reflection: Is the trend towards earlier onset of puberty related to the Flynn effect?
If I recall correctly, Ed Dutton has described geniuses as “intelligent r-strategists.” Just speculating, but maybe this assertion has more to it than the comparison first suggested?
As I think about it, the idea doesn’t seem totally apt, but it could have some points of merit. Maybe people with outlier-high intelligence are less constrained by the resource limitations in K-selected environments than the general population of such environments?
Again, this is mere speculation and likely doesn’t map onto reality in any clean way.
These are all born in the same cohort.