I was privileged to spend some time chatting recently with Dr. Kathryn Paige Harden. Harden leads the Developmental Behavior Genetics lab at the University of Texas-Austin and co-directs the Texas Twin Project. She is the author of The Genetic Lottery: Why DNA Matters for Social Equality (Princeton University Press, 2021), a fascinating and thought-provoking book that came out last fall. Harden’s book is a rare work that made me pause, reconsider, and begin to shift long-held beliefs. There are major implications for family policy and parenthood, which is why I asked her for an interview.
If you’re anything like me, your first reaction to any conversation about genetics that goes beyond pea plants or height is one of extreme wariness. Harden demonstrates why those of us interested in equity ignore genetics at our peril, while being explicitly clear how we can avoid the myriad racist and eugenic uses of genetics. I hope you’ll keep an open mind as you read the interview. It’s a conversation that certainly helped open mine.
Elliot Haspel: First of all, can you give an overview of The Genetic Lottery?
Kathryn Paige Harden: Sure. The book has two main arguments. The first is that genetic differences between us make a difference not just for physical outcomes, but also for psychology and behavior, and that ends up being relevant for social position in large part because of the outsized role that education plays in structuring American life. So, genes make a difference for cognitive skills, for personality, for health. All of that, of course, is not sufficient to do well in school; you also need opportunity. But all other things being equal, your genes make a difference for your likelihood of doing well in school.
At the same time, we see really big gaps, not just in terms of wages and wealth, but also physical health, lifespan, and psychological well-being—particularly between people who have and have not completed a college education. We can think of a chain: genetic differences are related to our psychology, our psychology is related to our educational outcomes, and our educational outcomes are related to how our lives go in adulthood.
The second part of the book asks how we think about that in a way that’s not deterministic or reactionary or asserting a biological hierarchy of people. That part is draws from John Rawls and other political philosophers who didn’t really talk about genes, but talked a lot about luck, chance, and what does a fair society look like if people differ in their luck in life?
A lot of times people think of it as nature versus nurture. That if differences in how people’s lives go are related to starting points in life that are environmental, that’s unfair and it’s our responsibility to fix things. But if people’s differences in outcomes are due to their genes, that’s somehow natural or unfixable or set in stone. I really want to challenge that view. If we had no idea what the outcome for our lives was going to be with either the social positions that we were born into or in the outcome of the genetic lottery—which genes we were born with—what kind of society would we want to set up? I think it would be different in a lot of ways from how we set up society right now, which really does privilege people who have a certain type of skill that’s valued in formal education.
You talk — and I appreciate this — about how we can think about genes in an anti-eugenic fashion, but also not completely ignore them. I’m fairly compelled by that perspective. I work in family policy, I’m a parent, you’re a parent. So to start, how do you think this should help us think about early childhood interventions?
When people hear about genes, they really want to jump to some sci-fi future where we’re going to personalize intervention or personalize education. I don’t think that’s the direction we’re going to go. I think there’s a much more basic problem to be addressed, which is that most interventions that we try in the educational space don’t make much of a difference. Many that have impacts have fade-out effects, and the ones that don’t have fade-out effects tend to have “Matthew Effects,” where the students who are already advantaged get even more advantaged. And that’s contrary to people’s very sincere intentions.
What that problem suggests to me—and I’m not the only one—is that our understanding of which factors actually cause which impacts in child development, and which mechanisms sustain change, is much weaker than most people realize. A lot of times I say that my enthusiasm for genetics scales with my pessimism about social science. I think the great power of genetics, in a lot of ways, is really at the research stage. How do we get past just “everything good is correlated with everything else” to actually think about causes?
In particular, it’s really hard to do that work in the field of child development and families, because almost all of the environments that we’re interested in are provided by or otherwise structured by children’s biological relatives. So, we run into the problem, Why are children similar to their parents? Or: Why are children’s outcomes correlated with aspects of their environments that are directly or indirectly related to their parents’ social status or behaviors? That’s just a huge, ubiquitous, hard-to-deal-with methodological problem. Genetics is just a tool to try to cope with that methodological problem, to make our science of child development better.
One area of study that you noted, that I thought was really fascinating, is whether growing up in poverty actually suppresses children’s genetic expression relative to children growing up in more well-off settings. And I read that to say, basically, that keeping children in poverty is preventing them from expressing their full genetic potential. That’s a mind-blowing thought. Can you talk about that finding?
There have been a lot of twin studies on this. Twin studies estimate how much genetics makes a difference for an outcome by comparing the similarity of identical twins with fraternal twins. So, if fraternal twins are much more different from each other than identical twins are, that’s a sign that the genetic differences between them are making a difference for their outcomes in some way, though we don’t know which genes or how. If you look at twin studies, it seems to be that heritability—the extent to which genetic differences are related to differences in your outcomes for measured cognitive ability, literacy, numeracy—is higher in children from higher SES [socioeconomic status] homes compared with children from lower SES homes.
That effect is not apparent in infancy, but it is apparent by toddlerhood. In kids as young as two years old, you start to see this divergence in the heritability of cognitive abilities between rich and poor children. Even though it’s very unreliable to measure cognitive abilities in two-year-olds, you still are seeing some pattern. The difference between low-income and high-income kids in the heritability of intelligence and academic achievement seems to get bigger over the course of development. It seems to be something that grows over time. And, if you compare samples of twins around the world, it seems to be a uniquely American phenomenon! You don’t see the same interaction in Northern Europe compared to the U.S.
Now, we don’t know why that is, but I think a really obvious hypothesis is that when we’re looking at twin samples from Norway or Sweden or the Netherlands, these are countries where low-income children have a lot stronger social welfare safety net, and their experiences of schooling are much less unequal across SES than you see in America. So, we do have some evidence that, to the extent that you have genetically influenced characteristics that make it easier for you to go further in school, it matters less if you’re in an impoverished context in a country like the U.S.
Here’s one way to think about this: You might have something that makes it easier for you to do well in math classes. And that thing could be better processing speed. That thing could be better frustration tolerance. It could be personality. But if your school doesn’t offer calculus, it doesn’t matter what genes you have, because you literally just don’t have the opportunity to learn.
That’s so fascinating to me. And so for the younger children, obviously you’re not talking about having access to calculus or being legally allowed to enroll in college. Is the theory that the differences in genetic expression are about the kind of environment kids are in, both in terms of how much stimulation they’re getting and the amount of toxic stress they’re experiencing?
I think it’s a variety of things. And this is a place where I think it’s really easy to use language that pathologizes low-income parents, and I don’t want to do that. One thing that’s made this really on the ground for people is the pandemic. You have kids and then all of a sudden, you’re tasked with educating them because school is closed. Then you think about how many more resources some people have to bring to bear to that problem. Do you have books in the house? Do you know what is developmentally appropriate for a five-year-old or a three-year-old? Can you throw money at the problem? Can you hire tutors? If you are working multiple jobs or stressed or have a precarious education or low literacy skills, that’s just so much harder to do.
Also, we have an early paper where we look at kids who have a genetic propensity for higher IQ. They tend to elicit more cognitive stimulation from their parents. So their parents respond to them. They engage in more developmentally appropriate stimulating play. And then that play predicts further growth. It’s a virtuous feedback loop.
How to teach that process in families that are less resourced is a really hard problem. Kim Noble did a study on the impact of money on babies’ brain development. Can you start it just by giving families cash? That’s honestly such an amazing study, and the fact we don’t already know the answer to that question is kind of wild. That seems like such a basic piece of information: How do we start those virtuous cycles of interaction?
We live in an era where the dominant mode of parenting is intensive parenting, this idea that you have to curate your kids’ experience to minimize the chances of hardship and to maximize the chances of success. I took some hope away from your book that given a reasonable environmental experience, for most kids, genetic expression will take them largely where they’re going to go. Is that a fair read? Do you think there’s any interplay between what your research says and how stressed we are as parents about our kids’ outcomes?
I feel like a lot of times genetics is used as kind of a referendum on parenting in a way that may be overly strong. One thing we see from the genetics research is that for attainments like education, something about parenting or the privilege that parents have is making a difference. The kids with the lowest polygenic score [combination of gene expressions relating to education] from rich families are still more likely to graduate from college than the kids with the highest polygenic scores from low-income families. We see in twin studies that about a third of the variation in college attainment is from their shared environment—so that portion of the variation is stratified by families, not due to genetics. These results are telling us something about what affluent parenting is doing. I think a lot of parenting among higher SES parents is motivated by the desire to buffer children from falling down the socioeconomic ladder—perhaps realizing some of your children might have academic weaknesses and buffering against those weaknesses.
For instance, in our math study, we see that your genetics is related to your persistence in high school math, but less so if you go to an affluent high school. Again, I think that’s telling us something about: “helicopter parenting” or “curling parenting” [intensively smoothing the path for kids]. I think these styles of parenting aim to buffer children from downward social mobility. And I do think that privileged parents are effective at doing that. Whether all the stuff we’re doing is necessary for that is a different question.
“What we do as parents to try to secure our children’s future has not, it seems, produced a generation of very happy or psychologically at-peace kids.”
My path to this topic was through being a clinical psychologist. And my focus when I was still a therapist was on adolescents. I’m really fascinated that we’ve seen this rise in student achievement, in investment, in enriching activities and this decline in risk behavior. And at the same time, adolescents today are the most anxious and depressed generation, with a huge mental health crisis.
So, I wonder, what are the psychological functions of risk taking throughout your lifespan? And how much does parents’ use of their privilege to try to prevent a downward drop in social mobility have the side effect of robbing kids of opportunities to practice risk taking, and what are the mental health consequences of that? In my mind, this question is related to how inequality is bad for everyone, not just people at the bottom of the pecking order. And I think one of the ways that inequality might be bad even for affluent people is the amount of fear and churning we experience. What we do as parents to try to secure our children’s future has not, it seems, produced a generation of very happy or psychologically at-peace kids.
Yes. I would agree with that. I’m very curious about how we find that proper calibration between providing the net but maintaining autonomy. My last question: I’ve been thinking a lot about your book as it relates to college admissions, which is a huge stressor for parents. I was thinking about this in dialogue with Michael Sandel’s The Tyranny of Merit. Sandel’s basic argument is that when you think about talent and luck and genetics being a part of the human equation, in some ways having a system with winners and losers isn’t fair. And so, I’m curious, when you talk about using DNA for social equality, do we need to start rethinking things like our college admission processes?
It’s not just that we need to rethink college admissions policies. We need to rethink the role of college in general as a rudder for steering the ship of social justice. One thing I really appreciated about Sandel’s book is how he points out that left and right, Republican and Democrat, this rhetoric of rising and striving and winning and competing has so dominated the mobility discourse. Even just thinking about the concept of social mobility right? It’s like, I’m here and I’m going to leave this group and I’m going to move here. I’m going to move up the income ladder.”
“If you think seriously about genetics, you end up in a similar place that Sandel does, which is questioning this whole meritocratic race. So, I would like less attention to be paid to the admissions policies at a given elite school and more to the question of what we are doing to secure a life of dignity and economic participation for everyone, regardless of how good they are at school.”
So much of the discourse around meritocratic competition in America is still focused on the idea that we should allocate goods by competing—that somehow competition is going to get at what kids deserve. Paying attention to genetics, in combination with social environments, has led me to the conclusion that separating outcomes out into luck versus what you deserve is difficult to the point of impossible.
Most of what we have in our adult lives was shaped by what happened to us before we were legally responsible agents—before we were 18. I have a colleague here at UT-Austin, Galen Strawson, who’s a philosopher of free will, and he’s famous for this phrase: Luck swallows everything. I think genetics has brought me to that. Luck plays a huge role in life and we can’t neatly separate things into who deserves what. If you think seriously about genetics, you end up in a similar place that Sandel does, which is questioning this whole meritocratic race. So, I would like less attention to be paid to the admissions policies at a given elite school and more to the question of what we are doing to secure a life of dignity and economic participation for everyone, regardless of how good they are at school.