Crémieux@cremieuxrecueil
A lot of people really don't know that elites give their kids HGH so they'll be taller!
Fewer people realize that this environmentally-transmitted advantage can be transmitted to future generations genetically.
How?
One of my favorite recent papers detailed this. The way this works is simple, but I need to introduce some background first: richer people have better genes.
What makes a set of genes "better" or "worse" when it comes to the attainment of a high level of social class is the degree to which the genes produce phenotypes that are conducive to social class attainment. So, for example, if being extroverted leads to earning a higher income as an adult, any genes that promote an extroverted personality will come to be associated with social class over time.
In the Western societies most of the people reading this live in, genes that promote educational attainment are also broadly associated with social class attainment. And importantly, these associations are not simply reflections of social class: the genes that affect traits that are relevant to socioeconomic status work within and between classes, and within and between families, too!
Here's an illustration of how genetic variants associated with educational attainment are stratified in four different cohorts located in the U.S., U.K., and New Zealand:
In these studies, individuals with more genetic variants positively related to educational attainment compared to their parents tended to be upwardly mobile. Individuals with more relative to their siblings also tended to outperform their siblings. And this happened to similar degrees regardless of people's social class backgrounds!
At the phenotype level, this finding has replicated for almost a century now. It first started being noticed in the 1920s, and the findings are substantially the same then and now, for most groups.
The genetic finding above replicated in another cohort based out of Minnesota. In it, it was shown that when a kid had greater cognitive and noncognitive skills than their parents, they tended to move up; on the other hand, when those things were worse, they tended to move down. The same was true when it came to their genes. But this finding also rang true when comparing siblings: the one with better genes, better skills, etc. tended to move up, whereas the one with worse genes, worse skills, etc. tended to move down:
This isn't a law-like finding and there are some qualifications. Firstly, social class of origin didn't seem to be a meaningful moderator.
Secondly, there's a big difference between education and the labor market. When it comes to education, if a child has worse skills than their parents, they tend to move down, but downward mobility is much smaller than the upward mobility difference when kids are better than their parents.
So for example, when the parent has greater skills than their child, 45% of the kids are educationally downwardly mobile compared to 27% who move up anyway. When the child has greater skills than their parent, 59% are educationally upwardly mobile compared to just 7% who are downwardly mobile.
On the labor market, where most parents can't compensate for their kids nearly as much, there's symmetry: when the kid has worse skills than their parent, 58% end up in worse occupations compared to 22% who do better; when they have better skills than their parent, 64% end up in better occupations compared to 24% who do worse.
Account for measurement error, and this becomes more dramatic, but I digress. Now, if we were to replicate this across all times and places, it's likely that some of the genes and even some of the traits we associate with success might not be associated with them in all of the possible different times and places. This happens because societies differ.
So for example, a von Neumann-level intellect in an uncontacted Brazilian tribe might not be heralded as a genius worth remembering for all time, and he certainly won't work on any atomic weapons. He might not even end up as, say, the village chief. That might go to his brother, Strongarms von Neumann who, incidentally, is highly-valued for his incredibly strong arms. Unfortunately for UncontactedTribalJohn von Neumann, he didn't end up with the miraculous strength his society values.
As I've noted before, in many societies, there's limited evidence for an association between traits like IQ or personality and socioeconomic status, but as time goes on and those nations have developed, the association in many places has also grown. So something has happened.
In some cases, it's trivial: aging happens. If IQ is relatively age-independent among adults, but socioeconomic status is strongly age-dependent as it is basically everywhere, less developed countries will show a weaker IQ-SES association because the age structure means there's more randomness in socioeconomic status and the relationship is attenuated. This also happened in recent history across much of the West, when the Baby Boom occurred, which is why it's no coincidence that inequality declined with the Baby Boom, because lots of young people means lots of noise in status attainment.
Now let's get to the meat, let's touch on how HGH improving a kids' height can lead to taller future generations!
The paper that describes how this happens deals with a different subject, but you can easily generalize. In it, Abdellaoui et al. showed that if there's a shock to a person's socioeconomic status, they really can translate that shock intergenerationally through genetics.
This doesn't have to do with epigenetics. It has to do with sorting on the mating market: when people assortatively mate on status-related traits, they aren't sorting themselves into couples based on their underlying genes, but on the appearance of those genes in the real world. So, if someone manages to earn higher status than expected given their genes, we should expect them to be able to find a mate with status that's closer to what you'd expect for a person with better genes.
In other words, you can trade status for the genetics of status, keeping status in the lineage for generations to come.
To show this, Abdellaoui et al. used birth order as an instrument for greater gene-independent socioeconomic status attainment. Their justification was sensible:
"It is known that earlier-born children receive more parental care and have better life outcomes, including measures of SES such as educational attainment and occupational status. On the other hand, all full siblings have the same ex ante expected genetic endowment from their parents, irrespective of their birth order. This is guaranteed by the biological mechanism of meiosis, which ensures that any gene is transmitted from either the mother or the father to the child, with independent 50% probability.... We can therefore use birth order as a 'shock' to social status."
The size of this shock in Great Britain was fairly large. The controlled cross-sectional birth order effect in terms of the impact of one additional elder sibling translates to a 7.9% lower chance of attending university, 0.077 standard deviations lower income, 0.27 points lower fluid IQ on a 13-point test, 0.7 centimeters smaller stature, 0.043 points worse self-reported health on a 4-point scale, and 0.19 points higher BMI. Birth order effects also showed up in Norway.
In both studies, a harmful birth order effect on a person's own status predicted worse genes in that person's spouse. Accordingly, this means that people really are exchanging status for a "higher-quality" spouse! The studies had different mediator variables available, but here's how those birth order effects were visibly statistically mediated in each country:
In both countries, the biggest mediator was education! Through improving a person's odds of obtaining a university education, being born earlier improves the likelihood that they'll meet a high-quality spouse.
Notably, in Norway, income didn't seem to be a mediator, and the effect of birth order on spousal genetic quality was about twice as large. This likely speaks to differences in how institutions affect social status in the two countries, suggesting that even within Europe and between two developed countries, the genetics of social status can operate in directionally similar, but quantitatively dissimilar fashions.
The implications of these findings are considerable, even though this finding only represents part of the total genetic stratification of social class in these societies, for various reasons.
For one, this confirms the supposition that advantage can be intergenerationally transmissible for more than environmental reasons. It also makes it possible for models like Fisher's to be more plausible in a sense because even though "the genetic theory seems to require very high levels of genetic assortative mating", this paper's social-genetic assortative mating model shows that "Persistence will be increased if, in addition to genetic assortative mating, high SES itself attracts 'good genes'."
The previously-mentioned differences between Britain and Norway also tell us that genes are not exogenous inputs, they're endogenous outcomes; for example they're "not a confound for wealth, but a mediator."
The way this translates to the HGH example is exactly as @snuppydogg has described. His cousin got a height boost, and he's going to cover it up by marrying a taller woman! And likely because he's taller than he would have been, he'll have an easier time making that happen. Why? Because height leads to higher incomes, more respect, more sexual attractiveness, and people like to assortatively mate—even on traits like height!
So the HGH bonus? Well, it might've started environmental, but in a lot of ways, it's going to be passed on genetically!*
To learn more, see: cremieux.xyz/p/intelligence… (also: x.com/cremieuxrecuei…)
* If everyone does this, maybe it washes out. If there are height-attractiveness thresholds, that won't be the case, but I don't know about that. Regardless, right now, everyone doesn't do it, so it's pure gain for the kid!
