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Thursday, February 10, 2022

Review: The Genetic Lottery - Why DNA matters for Social Equality

 The Genetic Lottery is a book about the social and research implications of gene studies and research. It sets out to defend gene studies primarily from a scientist and ethics point of view, mostly from the perspective of a researcher whose work has frequently been lumped in with the eugenics movement, which has long cast a shadow over genetics research. Along the way, she provides lots of information and interesting things to think about that I hadn't seen before. For instance:

As of 2019, people of European descent made up only 16 percent of the global population but accounted for nearly 80 percent of GWAS participants. This situation is not improving, despite the falling cost of genotyping. In the last five years, the share of genetics research focused on people of European ancestry has held steady, even as the overall number of genotyped people continues to explode. genetics research does not just disproportionately study White people. It also is disproportionately conducted by White people. The collection and analysis of genetic data from populations of non-European ancestry thus presents a double bind. Without conducting genetic research with the entire global population, there is a danger that genetic knowledge will only benefit people who are already advantaged.(Kindle Loc 1544-1546)

Harden presents the concept of a polygenic index very early on in the book, basically explaining it as an index of a constellation of genes that gives rise to a complex attribute such as height, IQ, and executive function EF.  The important property of these polygenic indices is that they measure composite complex attributes,  so they're difficult to manipulate. So there's a polygenic index for education, and there's one for wealth, and there's one for executive function. What's interesting is how early these genetic effects kick in:

the education polygenic index is correlated with whether children start talking before age 3 and their scores on IQ tests at age 5.12 So, consistent with what was observed in bioannotation and twin studies, polygenic index analyses suggest that, whatever genes are doing to influence educational inequalities, they are doing it early in life—with effects that are apparent before children ever begin school.... General EF is as heritable as eye color or height, more heritable than BMI or pubertal timing.14 (Kindle Loc 2479-2502)

 Harden points out several things about polygenic indices. First of all, they're not comparable between population subgroups. In other words, if you're not white, the studies that are published currently cannot be used to predict anything about you. Secondly, the genes might do something, but the environment matters. For instance, before women were allowed to go to college, the polygenic index for educational attainment was very weak for women (duh!):

For my grandmother’s birth cohort (people who were born in 1939–1940), the polygenic index was more weakly related to educational attainment among women than among men. (These women were in their thirties before my alma mater, the University of Virginia, admitted students without regard to gender, in 1972.) But this gender difference has narrowed over time: as educational opportunities for women increased, the polygenic index has become more strongly associated with women’s educational outcomes. For woman in my birth cohort (people born in 1975-1982), the polygenic index is as strongly associated with education as it is for men. Genetics, ironically, has become a sign of gender equality. (kindle loc 2761)

What this means is that it doesn't matter how heritable something is, if the gene finds itself in an environment where it cannot express itself. So for instance:

 Despite the mythology of the United States as the “land of opportunity,” it has lower social mobility than many other countries; Denmark is an example of a country with high social mobility. The heritability of educational attainment is actually lower in countries with lower social mobility, like the United States and Italy...the heritability of child cognitive ability is lowest for children raised in poverty and highest for children from rich homes—particularly in the US, where social safety nets for poor families are weaker than in other countries (kindle loc 2773-2779)

 She goes on to reveal that wealthy students in the lowest quartile of the educational attainment polygenic index still graduate college at higher rates than students in the highest quartile of polygenic index from the impoverished social classes. What this means is that there's a ton of un-realized human potential amongst the poorest students in the country, and that the genetic influence on education is still outweighed by the effects of poverty.

Harden then goes on to argue that attempting to do intervention in education, etc without the benefits of insights from genetic research is fruitless. For instance, there's an oft-cited study of how babies whose parents speak more words to them do better in school. But that sort of correlation doesn't mean anything. She claims that rolling out expensive educational policy blindly without any sort of understanding of how the genetic influences work is unsustainable and lead to failure. Most educational interventions do in fact fail.

Where Harden falls down, however, is that she states near the end of the book that we do know what works. Universal healthcare, for instance, would eliminate a lot of the immiseration and suffering and poverty that causes poor performance amongst students. Similarly, eliminating hunger amongst children through food-stamps or poverty reduction programs directly help those students. So in the very last chapter of the book she under-mined her entire thesis! It's very clear that the progressive programs that are considered "far-left-wing" in the USA (while being solidly in the center-right in most developed countries) do not need further research in genetics, cohort studies, or eugenics programs in order to be successful. We already know how to do them, we just have never had the poliltical will to do them.

But you know what, I'm going to give Harden credit for this. Very few people (scientists or otherwise), will admit that the problem they're applying for research funding for has already been solved. And her book contains many good examples of how targetted intervention for kids with say, ADHD or other disabilities shouldn't be considered any differently than giving kids with myopia glasses to see better with. So on the whole I still think her book is worth reading.

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