EA and cognition polygenic indexes (PGIs) in three British birth cohorts show EA PGI associations with years of education increased from 1946–1970 and were strongest in advantaged socioeconomic backgrounds.
0:00Welcome to Base by Base, the paper cast that brings genomics to you wherever you are. Thanks for listening, and don't forget to follow and rate us in your podcast app. Okay, so I want you to picture something.
0:11A hospital delivery room. You know, it's loud, it's chaotic, the lights are way too bright. Two babies are born. Same second, same city. And let's just say, for the sake of argument, It's a total miracle of biology.
0:23These 2 kids have the exact same genetic potential for learning. Okay, so their brains are wired with the same capacity, the same raw heartbreak. Exactly the same. To be brilliant, to solve problems, anything.
0:36Now, fast forward 30 years. Do they have the same life? That is, I mean, that is the ultimate question, isn't it? Right. Does the kid with the PhD genes actually get the PhD? And we, we like to tell ourselves that talent wins out.
0:48You know, we have this cultural belief that DNA is this unstoppable blueprint. If you have the code for high intelligence, it's just gonna manifest. It will find a way out. Like a flower growing through concrete.
0:58Meritocracy. Yeah, the cream rises to the top. But the deep dive we're doing today. It really throws a bucket of cold water on that whole idea. How so? The data we're looking at suggests that your DNA doesn't just act on its own.
1:13It sort of asks permission from your parents' bank account first. Wow. We're finding that for some children, their genetic potential is a rocket ship. For others, it's a car with no engine. And the difference isn't biology.
1:26It's money. That is a staggering thought that you could have all the biological tools to be the next Einstein, but the environment just neutralizes them. Exactly. makes you ask, are we actually measuring ability in our society?
1:39Are we just measuring opportunity? And to help us answer that, we really need to acknowledge the team who crunched all these numbers. I mean, this isn't just speculation. This is hard data. Right. This comes from the Center for Longitudinal studies at University College, London.
1:51Yes, so huge credit to Tim T. Morris, Liam Wright, Jimmy Sharby, and David Bann. They're the heavy hitters behind this work. And what they've done is just so ambitious. They didn't just look at a survey from last year or something.
2:04No, no. They use these massive data sets to look at how genetics and socioeconomic contexts have intertwined over nearly a century of British history. So let's unpack the context a bit. Why is this specific intersection genes versus money, so incredibly difficult to study?
2:21Well, social scientists have debated the drivers of what they call educational attainment or EA for, I mean, forever. We know that educated people tend to be healthier, wealthier, we also know it runs in families.
2:34Right, the classic chicken and egg problem. Is it because the parents passed down smart jeans or is it because they had a house full of books and paid for tutors? It's nearly impossible to separate them.
2:44Parents provide both the nature and the nurture. You get their DNA and you get their dining room table conversation. So you can't untangle it. Not easily. And historically, we've seen some gaps close. The gender gap in education, for example, has largely reversed in many places.
2:59Women now outperform men. But the class gap. The socioeconomic gap is stubborn. In many places, it's either stable or it's actually getting wider. So how does the study tackle that differently? How do they slice that knot?
3:13By using DNA as a control variable. See, surveys can be biased. People misremember things. The way we measure class changes over decades. But your DNA. Your DNA is a constant baseline. It's a constant.
3:26It doesn't change when you lose your job or move house. It acts as this fixed anchor point to measure everything else against. It's the one variable that's constant from conception to death. Precisely.
3:38And the global relevance here is huge. This isn't just about biology. It's it's really a checkup on the promise of social mobility. I mean, on equality of opportunity. Yes. If society is truly fair, then your genetic potential should predict your success equally, whether you're born in a mansion or you know, a council estate.
3:56This study really investigates if we're living up to that. Okay, let's get into the time machine aspect. You said this covers nearly a century. How on earth do they have genetic data going back that far?
4:04This is where the UK is just a phenomenal resource for science. They use 3 legendary birth cohorts. First, the 1946 National Survey of Health and Development. So these are kids born right after World War II.
4:18We're talking ration books, rebuilding London, a completely different world. A different world. Then they use the 1958 National Child Development Study. Post-war boom, the Beatles are about to happen. And finally, the 1970 British cohort study, the disco era, modernization.
4:36And they have genetic data on 1000s of these people. They do, which lets them track how the link between genes and success changed as the entire world around them was changing. Okay, so let's define the tool they're using here.
4:48We're going to hear the term PGI a lot. I know what Sam's for polygenic index, but can you break that down for us? Think of it like a credit score, but for your genome. It's absolutely not one single smart gene.
4:58There's no gene for getting a PhD. BGI is a score that aggregates thousands, sometimes 1000000s of tiny genetic variants. These are the SMPs, right? Little spelling differences in our DNA code. Yes. And individually, one of these variants does almost nothing.
5:15It's like a single drop of rain. But when you add up 1000s of them that statistically correlate with, say, staying in school longer, you get a score. A PGI. So a high PGI for education doesn't mean you will get a degree, it just means you have a kind of genetic tailwind pushing you that way.
5:33A probability, not a destiny, exactly. But here is the really innovative step the UCL team took, and this is crucial. They didn't just use one PGI. used two. Two. Two. They created one PGI for educational attainment.
5:46Let's call it the school success score, and a totally separate one specifically for cognition. Wait, I assume those would be the same thing. Doesn't school success just come from cognitive ability? You would think so, but they're distinct.
5:57The cognition PGI is strictly linked to things like intelligence tests, processing speed, memory, raw brain power. And the other one. The education PGI captures that, yes. But it also captures everything else associated with staying in school.
6:11motivation, patience, conscientiousness, you know. The ability to tolerate boredom. The ability to organize your time. It's a mix of brains and behavior. Okay, that distinction feels like it's going to be really important later, but first, there is one more technical thing they did.
6:25This inverse probability waiting. Yes, and I know that sounds super dry, but it's actually really clever. Imagine you're trying to predict an election. You call a 1000 people, but young people never answer their phones.
6:39But older people always do. Right. So if you just tally the votes from who answered, you'll get the wrong winner, because your sample is skewed. It's skewed toward the people who are easy to reach. Exactly.
6:51And the same thing happens in these long-term studies, who drops out over 50 years, people with chaotic lives, people with lower incomes? The survivors in the data set tend to be wealthier and more stable than the real population.
7:02So if you don't fix that, your study on inequality is biased because you've lost the most unequal people from your data. Precisely. So inverse probability waiting is like a megaphone. The researchers find the few people from those disadvantaged backgrounds who did stay in the study, and they mathematically turn up the volume on their data.
7:20to kind of ghost the missing population back in. That's a great way to put it. It ensures we're not just looking at the lucky ones. Okay, let's get to the findings. You mentioned that genetic influence is actually increasing.
7:31Yes. This is finding number one. The timeline shift. They looked at how well that education PGI, the school success score, predicted how many years people actually stayed in school. For the 1946 cohort, the genetics explained about 3.5% of the variants.
7:493.5% feels pretty small. It is, but look at the trend. By the time you get to the 1970 cohort, that number jumped to 5.one%. So the link is getting stronger. The link between your genes and how long you stay in school is getting stronger over time.
8:04Why? I would have thought as education became more accessible, you know, free universities and so on, that genetics would matter less. It's actually the opposite logic. Think about it. If the environment is terrible for everyone.
8:19If school costs a fortune, it doesn't matter how smart you are. No one goes. Heritability is zero. Because the environment crushes everyone equally. Ah, I see. But as you remove the barriers, the money excuse goes away.
8:33The only thing left to differentiate people is their natural aptitude. Exactly. In a perfectly fair society, genetics would explain 100% of the variants. So seeing this number go up suggests the UK was becoming more of a meritocracy.
8:46Okay, that makes sense. A fair society means higher genetic influence, but I have a feeling there's a butt come in. There is. This is finding number two, the technician surprise. Remember how we separated the school success score from the raw brain power score?
9:00Yes. Well, the school success score became more predictive, but the cognition score. It's date flat. It predicted the same amount of variants in 1946 as it did in 1970. Wait a minute. So genes are becoming more important for educational success, but the genes for intelligence aren't.
9:15What does that even mean? That implies the extra genetic factor that's becoming so important isn't how smart you are. It's those other traits, the grit, the conformity. It suggests that as the education system expanded, It didn't necessarily start rewarding the most brilliant minds.
9:31It started rewarding the most compliant and organized minds. The non-cognitive skills are what's driving this new genetic advantage. That's kind of unsettling. It makes you wonder if we're building a system that filters for obedience rather than innovation.
9:44It's a valid concern. We might be selecting for people who are good at school, not necessarily people who are good at thinking. But even that feels small compared to finding number three. This is a big one.
9:54The interaction between genes and money. The gene by environment interaction. This is the core of the whole paper, and the visual is just striking. Describe it for us. What does it look like? Imagine a fan opening up.
10:06For children from wealthy, educated backgrounds, the high SES group, the line is steep. It's a rocket ship. If you have high genetic potential and rich parents, your education just skyrockets. The environment amplifies the genetics.
10:19Okay. And for the kids from the poorest backgrounds. The line is flat. Flat. Effectively flat, it means that for children born into the lowest occupational class, having a high genetic potential resulted in barely any more education than having a low genetic potential.
10:35So if you're poor, having the smart genes doesn't actually help you. It suppressed. The environment acts as a hard ceiling. It doesn't matter how powerful the engine is if the garage door is locked. There was that specific comparison in the data that just floored me, the one about the high potential poor kid.
10:52Yes. The study predicted that the educational outcome for a person with very high genetic potential, top one%, but born into a disadvantaged background. What was roughly equal to? A person with very low genetic potential, bottom one% born into a privilege background.
11:08That just completely dismantles the idea of a level playing field. It suggests that money can override a lack of aptitude, and poverty can completely suppress high aptitude. It suggests potential is a luxury good.
11:21If you're wealthy, your potential determines your outcome. If you're poor, your environment does. So let's talk about the implications. We started this asking if society is a meritocracy, and this data suggests, at least for the lower classes, it absolutely was not.
11:39It really validates what sociologists call resource capture. Wealthy families use their resources to maximize their kids' advantages and buffer their disadvantages. It's the safety net versus the launchpad.
11:51The wealthy kid gets a launch pad if they're smart, and a safety net if they aren't. The poor kid gets neither. Yeah. And this has huge policy implications. We often hear politicians say the solution is just better schools.
12:02Right. Fix the schools, fix the outcome. But this research suggests that's not enough. If the home environment is acting as a hard ceiling for talented kids before they even walk into a classroom, we have to look there.
12:14We have to look at poverty itself. We're talking about the lost Einsteins. That's the term. How many brilliant minds are we missing out on? Simply because the high potential kids were born into low opportunities zip codes.
12:25And because the environment suppressed their genes, we never even knew they had the potential. We just looked at their dropout rate and said, oh, they're not academic material. Exactly. Well, the C student from the wealthy family gets the tutor, the internship, the 2nd chance, and eventually graduates and takes a high paying job.
12:41I want to circle back to that cognition versus education thing. If the education PGI is what's changing. And that includes personality. Does that mean we need to rethink how we teach? It might. It raises the possibility that the modern education system is structurally biased toward a specific personality type.
13:00You know, if you are smart, but restless, or smart, but disorganized traits that might be more common in chaotic, high stress environments, the system just filters you out. Right. It's a lot easier to be motivated and calm when you aren't worrying about where your next meal is coming from.
13:17Exactly. The environment isn't just the bank balance. It's the cognitive load. It's the stress that consumes the bandwidth you need to demonstrate those soft skills. No, we have to be responsible here.
13:29We can't just generize these results to the whole world, can we? No, and the authors are very clear about this limitation. This study is limited to white individuals of European ancestry. And why is that?
13:40It's a limitation of the current genomic data itself. Most large scale genetic studies have historically been done on European populations, and these polygenic scores don't transfer well across different ancestries.
13:53So we have to be very careful not to assume the supplies everywhere. Or to other groups. Right. And we always have to remember. Heritability describes a population, not a person. A PGI is a probability, not a diagnosis.
14:07So bringing it all home, what's the big take home message from this deep dive? I think the summary is this. Genetic influence on education isn't static. It changes, but biological potential requires sociological opportunity to flourish.
14:21So it's not nature versus nurture. It's nature multiplied by nurture. That's the perfect way to put it. Genetic liability and social background are 2 forms of inherited advantage, and they work together.
14:31If you have both, you win big. If you have neither, you struggle. But the tragedy is when you have the genes, but not the background. In that case, the background wins. That is a sobering thought. It makes you realize that talent is a fragile thing.
14:43It really needs the right soil to grow. It does. So I want to leave you with a provocative thought to mull over. We've been talking about this in terms of fairness, but think about it in terms of pure economics.
14:55If genetic potential is being wasted, flatlined, and disadvantaged environments. What is the cost to our civilization? We are leaving a huge amount of human capital on the table. Exactly. If our scholarship systems and our job markets are designed to reward the outcome, the grades, the degree rather than the raw potential.
15:14Are we just rewarding the rich for being rich? And if we fix that, what problems could those lost Einstein solve for us? That is the question we should all be asking. This episode was based on an open access article under the CCBY 4.0 license.
15:29You can find a direct link to the paper and the license in our episode description. If you enjoyed this, follow or subscribe in your podcast app and leave a 5 star rating. If you'd like to support our work, use the donation link in the description.
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