All in Our Genes

A discussion with Robert Plomin

I had a fascinating conversation with Robert Plomin, a behavioral geneticist at King’s College London, for the CSPI podcast. He is also the author of Blueprint: How DNA Makes Us Who We Are.

We discuss topics such as how we know genes are important, consumer genomics, what is happening on this front in other countries, including the UK and China, and the p factor of mental illness.

In addition to the audio, there is a transcript below, lightly edited for clarity. During the interview, I realized that Plomin and I had both been blown away by the massive effect sizes we saw in the behavioral genetics literature. As I told him, I don’t believe that you can look clearly at the science and not have it fundamentally shape your views on politics, society, and ethics.

And then in our intro to political psychology course, we had a few weeks on genetics out of 10 weeks we had with the quarter system at UCLA. I knew this literature and I knew the methodology better than the professor did because I had done a lot of reading on it. And, of course, better than the students too.

And then at one point he asked me, “these effect sizes are absolutely massive. When they say 60% of the variation is explained or 80% of the variation is explained, does that mean what it means in the rest of psychology?” And I said, “Yes, it does.” That's a clue that what these behavioral geneticists are doing is very, very important. So, we were getting into things like the heredity of political beliefs and things like that.

But, yeah. I mean, I didn’t become a behavioral geneticist but I am with you, in that this stuff is absolutely, it’s mind blowing. I mean, I think the nature versus nurture question is just pretty much something, you could call it the fundamental question in the social sciences. And everything, I think, has to be built on that. You have to understand, before you understand anything else, just how much of what we are is genetic and how much is just the rest of the environment before you even get to which environmental effects are having an influence on us.

Plomin replied,

Yeah. Well, that’s exactly what floored me in graduate school in this core course, they used to call it behavioral genetics, is that these weren’t just statistically significant findings. We’re talking about, on average, say 50% of the variance, that is the differences between people in all psychological traits, is due to inherited DNA differences. Now, that isn’t 100%, but 50% is off the scale. You know, there are very few psychological findings you can point to that account for 5% of the variance. So, it is extraordinary, and that’s one of the things I noticed.

In addition to the social sciences, there are also deep implications of this research for parenting and education, as we get into.

For those who are unfamiliar with the behavioral genetics literature, Judith Rich Harris’ The Nurture Assumption is still a great resource, although it was written before the era of cheap DNA sequencing. It is worth learning the little bit of biology and algebra it takes to understand the basics of the field. Over the next few decades, the extent to which behavioral genetics finds acceptance and wide application will be as good a litmus test as any for judging the health of our politics and intellectual life.

[Beginning of transcript]

Richard: Hi, everyone. Welcome to the CSPI Podcast. I’m here today with Robert Plomin. Robert, how are you today?

Robert: Fine, thank you. I’m pleased to be here.

Richard: We're here today to talk about your book, Blueprint: How DNA Makes Us Who We Are. Before we get into it, can you just talk a little bit about your background, what do you do, and maybe just a little summary of what the book is about?

Robert: Yeah. I’m a psychologist, and I got into behavioral genetics in graduate school sort of by chance. I went to the University of Texas at Austin, and they’re the only place in the world that had a program in behavioral genetics back in the early 70s. So, I got in there at the beginning, and it's been quite a ride in the subsequent almost 50 years now, getting into the DNA revolution.

This book, Blueprint, is a summary of ... Well, more than a summary. It's my take on where we've been over these 50 years. And as I said, it’s been quite a ride because when I was in graduate school in Psychology, you wouldn’t see the word genetics. We were taught that schizophrenia was caused by what your mother did to you in the first few years of life. Psychology was completely dominated by environmentalism, the view that you are what you learn.

So, I think the field has changed dramatically over these years. It’s sort of a mountain of evidence showing the importance of genetic influence, that is inherited DNA differences. And then in the last 10 years, the second stage of this rocket took off, which is the DNA revolution, where we can actually identify specific bits of DNA that predict behavior. And that's what my book is about, basically, how DNA makes us who we are.

Richard: Yeah. So, you said the University of Texas was the only behavioral genetics department in the country in the 1970s?

Robert: Yeah. It’s quite interesting. It was very much by chance. That was after the Sputnik era in the late 60s where universities were given truckloads of money to catch up.

So, Gardner Lindzey, a former president of the American Psychological Association, was really trained as a Freudian. He did work on incest taboos. But in the 60s he began to see that genetics was important. And so, to lure him from Harvard, the University of Texas at Austin asked, “What would you like? What can we give you?” And he said he’d like to hire all the behavioral geneticists in the world, which was about six people. And so, he brought them all to the University of Texas. They had this excellent program in behavioral genetics.

Back in those times, I don’t know if it’s true anymore, but when you go into graduate school in psychology, you had to take two years, basically. It’s a four-year program. Two years of courses. It was like being an undergraduate. They assumed you didn’t know anything about psychology, so you had to take courses in perception, and clinical, and personality. So, all major areas of psychology, and one of those, at Texas and nowhere else in the world, was behavioral genetics.

And so here I was in this class with 40 new sort of PhD students. This was actually towards the end of my first year in graduate school. It just floored me. I just knew from the start that this is what I wanted to do because I hadn’t known anything about it, I’d gotten nothing about genetics, and I saw some of the early work, especially animal studies, and I was impressed by the power of the findings. But what’s even weirder is I was with 39 other very bright students, graduate students in this program, not one of them went on to become interested in behavioral genetics.

So, it’s an example of the idiosyncratic experiences that are so important in our lives. That's part of what Blueprint is about. That is, the environment works very differently from the way we thought it worked. The environment’s important, but it’s not due to the systematic effects of family environment that psychologists from Freud onward always assumed that that’s the way the environment works. But it doesn’t. Whatever it does, it’s making two kids in the same family different from one another. We call this non-shared environment, but we'll probably get into that a bit later.

Richard: Sure, yeah. This reminds me actually of a story. I mean, my background is in political science, I took a class in political psychology. I had read both the twin studies and the adoption studies so I knew about the role that heredity plays in human behavior and determining differences between individuals.

And then in our intro to political psychology course, we had a few weeks on genetics out of 10 weeks we had with the quarter system at UCLA. I knew this literature and I knew the methodology better than the professor did because I had done a lot of reading on it. And, of course, better than the students too.

And then at one point he asked me, “these effect sizes are absolutely massive. When they say 60% of the variation is explained or 80% of the variation is explained, does that mean what it means in the rest of psychology?” And I said, “Yes, it does.” That's a clue that what these behavioral geneticists are doing is very, very important. So, we were getting into things like the heredity of political beliefs and things like that.

But, yeah. I mean, I didn’t become a behavioral geneticist but I am with you, in that this stuff is absolutely, it’s mind blowing. I mean, I think the nature versus nurture question is just pretty much something, you could call it the fundamental question in the social sciences. And everything, I think, has to be built on that. You have to understand, before you understand anything else, just how much of what we are is genetic and how much is just the rest of the environment before you even get to which environmental effects are having an influence on us.

Robert: Yeah. Well, that’s exactly what floored me in graduate school in this core course, they used to call it behavioral genetics, is that these weren’t just statistically significant findings. We’re talking about, on average, say 50% of the variance, that is the differences between people in all psychological traits, is due to inherited DNA differences. Now, that isn’t 100%, but 50% is off the scale. You know, there are very few psychological findings you can point to that account for 5% of the variance. So, it is extraordinary, and that’s one of the things I noticed.

It was mostly in the 70s, early 70s. The research in the 60s was basically animal research, which is very powerful. Because if you can select for behavior, like in mice who have very quick generations, you can get three or four generations a year in mice, it's sort of the proof of the pudding of genetic influence that these children, the offspring, the pups will resemble their parents. So you really can select for these traits, which animal husbandry has known about for thousands of years. They knew you could select not just for bodies but also for behavior.

That’s the sort of thing that really made me sit up and pay attention to it. But I’m kind of amazed that you brought that into political science, or political psychology even, because it was pretty rare that you would get any sort of genetics in those courses. But now, I think political scientists, economists are leading the charge for genetic influence.

Richard: Yeah, I hope that’s true. I mean, the reaction of the students, they were just more skeptical of it than just about anything else. They were even uncomfortable. The discussion would always drift towards what are the political and social implications of this, which we would never do with any other thing. The resistance is still very strong even though it was on the syllabus and we did talk about it. So …

Robert: I don’t know why the environment gets to wear a white hat, and genetics has the black hat.

Richard: I agree, yes.

Robert: Because you think of, just an example I gave of schizophrenia. Mothers back in the 70s, you don’t know you have a schizophrenic child until they’re in their late teens or early 20s. And then you’re told, well that’s a lifelong sort of chronic condition. And then you’re told it’s what you did to the kid in the first few years of life. I mean, how wicked is that especially because it’s dead wrong? There’s no evidence that that’s true. And yet, that’s what parents would have been taught, and that’s why parents of children who grow up to have psychopathology are the biggest supporters of genetic research.

Some people say, “Yeah, well, it gets them off the hook.” But that really pisses me off because they aren’t on a hook. It's not their fault, it’s not due to their parental treatment of the children, which was what always was assumed to be causal.

So, I think it’s a very important point that increasingly, I’m a cheerleader for genetics because there seems to be still this residue of resistance against the notion of genetic influence. And if you really understand it, you realize it’s not bad. I mean, it’s important, and important findings can be misused as well as used. But there’s an awful lot of good that can come out of it especially with the DNA revolution and being able to identify specific DNA sequences. So, I'll probably end up doing a bit more cheerleading here as we talk.

Richard: Well, I mean, yeah, I couldn’t agree more. We can get to the science and we can get to the political and social implication. But just because we’re going on this path, I’m interested in science funding and how just sort of the systems of knowledge production work. I mean, I’m just interested to hearing this story, maybe pulling on this a little bit more.

So, in the 1960s, that was when the UT Austin Department started. That was before modern twin studies and adoption studies, right? What were the first ones to have been done?

Robert: Well, the very first twin studies were done in the 1920s and then the first adoption study was done in the early 1930s. But then what happened is the Second World War and Nazi Germany, and that put an end to any genetic research. And about the same time, JB Watson, John Watson, started behaviorism, which led to environmentalism. It’s the idea that we are what we learn basically. It’s a learning approach to important experiences in psychology, and that so dominated psychology. It fit with Freudian thinking as well.

And so, until the 60s, there was really very little genetic research. The little bit that was done was more in Europe. But then, I think psychiatrists first in the 1960s began to realize that this idea that heredity is of no importance just doesn’t fit with your experience as a clinician.

There was the famous adoption study in 1966 showing that kids adopted away from their schizophrenic parents were just as likely to become schizophrenic as kids reared with their schizophrenic parents. That was Heston’s study in 1966. That really got psychiatry moving towards genetics, but psychology hadn't gotten there yet.

And then in 1969, Jensen had this article in the Harvard Educational Review talking about the importance of genetics. At the request of the editors, he was asked to say something about race differences, and that really lit the fuse. You know, there's no reason to think that genetics might not be important; but nonetheless, that really got it going. And then Herrnstein and Murray wrote The Bell Curve in 1996 [note: actually 1994]. As things were dying down from Jensen, it all took off again.

I think we are making progress. But in the 80s and 90s, there really has been a mountain of evidence not just from twin studies comparing identical and non-identical twins but also adoption studies and family studies, and now DNA studies.

It's really hard to argue with DNA. You can say, well there’s some assumptions in the twin method. The adoption method also has some assumptions, like maybe kids are selectively placed into homes that are similar to their birth parents. But importantly, twin and adoption studies have completely different assumptions, and if they come up with the same conclusion, you ought to take notice of that. But now with the DNA revolution, we can say, look, these sequences of DNA predict behavior. It's really hard to argue with that.

Richard: Yeah. I didn’t know that the Jensen article ... I mean, I didn’t know the part about race was at the request of an editor. That’s a funny little historical anecdote. Because the reaction would have been completely different had it not been in there.

Robert: That’s right. And it was interesting because he was very much an environmentalist, Jensen, in the ‘60s. He was in educational psychology. But then, he started seeing, sort of like me, started seeing some of the evidence for genetics. And he stuck his toe in the water a bit, he became more and more convinced by the studies, and they were really starting to come out at about that time.

Richard: Aha. Yeah, sure. It sounds like the initial funding, you said it came after Sputnik, so it wasn't as if there was this big push. I mean, so you had this taboo on genetic research after the Second World War, and it seems like it was not so much that anybody really wanted to study this. A few people did, but it's just that there was so much money available, that they were throwing money at all kinds of things, and this happened to be one of those things that turned out to be very, very powerful. Is that your understanding of the history of it?

Robert: Yeah. It’s a little more complicated. They weren’t throwing money at genetics because you still had to get past review groups. When I took my first job ... I went from the University of Texas to take my first job at the University of Colorado. I wanted to do an adoption study because there were a number of twin studies, but there were very few adoption studies. And so, I thought it’s important to use this very different method.

So, I had to try for about ... This was as a beginning assistant professor. I wanted to get a longitudinal study where we studied kids from birth who were adopted away into adoptive families, and then test the birth parents as well. Because back in those days, in the 70s, there were a lot of adopted kids because birth control wasn't really available then despite the swinging 60s. There were a lot of women getting pregnant, and abortion wasn’t really possible either for young single women. So, a lot of them gave their babies up for adoption. There were quite a representative sample too; it wasn’t just people with problems, for example.

So, I thought it would be a good time to do it. And it was really the last time you could have done it in the early 70s because by the later 70s, abortion became possible, but especially contraception.

So, I wanted to do this study, but it’s sort of like the exact wrong thing to do as a new assistant professor. You want to do a large scale, long-term, longitudinal study. I tried three times to get funding. It was really negativity towards the idea that I was going to do a study that would look at genetic influence, but I persisted. It took about three years to get funding.

In the meantime, I was spending all my weekends driving from Boulder, Colorado to Denver where these residential homes were for, they call them, unwed mothers. These are where women would come from another state in the last trimester and live away so that they could have an excuse so that no one back in their home territory would know that they had been pregnant. I spent my weekends going there testing these unwed mothers on a three-hour battery of tests because I didn't have any money to do it at that time.

We ended up with some 250 children adopted away where we tested their birth mothers, sometimes their birth fathers as well. And then we had matched control families, matched to the adoptive families who adopted these kids. That meant we had parents who were genetically related to the adopted away kids, the birth parents, but not environmentally related; then we had environmentally related parents, the adoptive parents of these kids; and then we had control parents. There's no good word for it. You don't want to say ‘normal parents,’ but parents who share genes and environment with their kids.

Richard: Right.

Robert: It’s a really powerful design. We found what the genetic studies showed, like twin studies. The amazing thing, if you just take, it’s probably a bad example because people still get uptight when you talk about intelligence or general cognitive ability, but the correlation between parents and their offspring, when the offspring are, say, adolescents, is about 0.35. I assume your listeners know what a correlation is from zero to one. So, 0.35.

Richard: I think most of them will, yes.

Robert: Yeah. And people knew that forever in developmental psychology. They said, “Yeah, it's just environmental.” Parents who are brighter give their kids a better environment and the kids then grow up to have higher IQ scores.

But you say, “What about genetics?” It turns out that the correlation between the birth parents and these adopted away kids, and in those days the birth parent never saw the kid after the first few days of life, it’s part of the deal. They correlate just as much as the parents who reared their kids. And then just to finish it off, what's the correlation between the adoptive parents of those adopted children where they raise the kids from the first few months of life but they don't share genes with the kids? The correlation is zero.

So, it seems to me a very powerful data not only showing genetic influence but also showing that the environment doesn't work the way we thought it worked. That is, the environment's important because genetics accounts for about 50% of the differences. The environment's the rest of it. But it’s not the systematic effects of family environment because those adoptive parents’ IQ is not related to their adopted children's IQ. So, that's this issue of non-shared environment that I mentioned earlier.

So, the funding was very difficult. But then, it’s never really easy because the government doesn't decide who gets funded. I’ve been involved in these five-year plans many times, but it doesn't really translate to what gets funded very much because it's these guys on the review committees that decide, and they have their prejudices and everything.

If you’re trained as an environmentalist, it really takes a lot for you to give credence to this idea that genetics is important. But then, I think as you got into the 80s, it became easier because I think the writing was on the wall that genetics is important.

Now we're at a point where, back in the days, in the 70s, I’d have trouble getting money to show that genetics might be important. Now, you couldn't get money for that because people know everything is heritable. The real trick, the challenge is to find any psychological trait that shows no genetic influence in an adequately powered study.

Richard: Yeah.

Robert: So, it's really been a remarkable ride over these 40 or 50 years.

Richard: Yeah. One thing I like, Robert, in your work and listening to you, I’ve listened to some of your interviews, is there is a tendency to undersell the stuff, right? The fact that, well, the finding that you just said, that if your parents give you up at birth, you are just as similar to them in IQ and other traits as you would be if they'd raised you, and the person who adopted you has no correlation with you any more than any other stranger on something like intelligence. This is not something ... Okay, there's caveat like it doesn't matter cross-culturally, it doesn't measure every potential contingency or abuse or whatever. Sure, we could have all those caveats, but what's left even after those caveats is absolutely massive and earth shaking.

This is something that everyone should know. I mean, I think it should be something that you are taught before. I think it should be in intro to econ courses, I think it should be in intro to political science, I think it should be in psychology. I think politicians and public intellectuals need to keep these things in their head. I think it's revolutionary.

A lot of people will say this stuff and say, okay, now we can go back to our old political discussions that are old assumptions about the way the world works. But I just think that's wrong. I think really appreciating this stuff has to shape your view in one way or the other.

Robert: Yeah. Well, I couldn’t agree more. I’m going to quote that because I ... In Blueprint, for example, the four pages in the books that get the most attention are four pages in which it’s provocatively called “parents matter, but they don't make a difference.” So-

Richard: Yeah, sure.

Robert: ... you could see where that rubs people up the wrong way. But like you’re saying, I want to get people’s attention here. I want to say that the most important thing parents need to know about childrearing is genetics. And yet, you look at the literally thousands of books on parenting, try to find one that takes genetics seriously. They don’t. They all assume that parents have to follow what doctor so and so says or their kids are going to be screwed up. I think that’s really wicked because there’s a lot of anxiety in being a parent. I think what parents need to know is that most of the variance is out of their control. It’s genetic. And what’s worse is the environmental variance, I think, is largely due to idiosyncratic stochastic chance influences, which parents don't have control over either.

So, the implication of this is not that parents don’t matter. They do. Kids can’t grow up by themselves. Growing up, as Judith Harris used to say, who wrote this famous book about shared and non-shared environment, The Nurture Assumption is what it’s called. She says parents matter a lot because it’s a large part of the parents’ life and the child's life, and the relationship is very important. But you don't become a parent to mold your kid to be what you want it to be.

I think the genetic message is find out what your kid likes to do; help them do it; but mostly, enjoy the relationship. I think a good analogy is if you married someone because, you said, “Well, there's some good material here. I'm going to make him into someone that's really to my liking,” it’s a recipe for disaster. But that’s what so many parents do with their kids. They think that the way their kid turns out is just due to the way they parented them. That’s really bad.

It’s really bad when I get letters at least every couple weeks from parents, especially adoptive parents, where they assume that DNA isn't important. They don’t think of DNA, they just think of TLC. I knew this in the 60s and 70s especially where feminists would get pregnant just by going to a bar some night, having a one-night stand and-

Richard: Really? Was this a widespread practice?

Robert: Pardon me?

Richard: Was this a widespread practice?

Robert: Well, I don’t know. This was Boulder. [laughter]

Richard: Okay.

Robert: A pretty hip, out there, sort of place. But I mean, seriously, they just thought TLC matters. You know, tender loving care. DNA never entered their mind. You hear from these adoptive parents who ... It’s a pretty representative sample back in those days which kids are adopted, but that means the average IQ is 50 [percentile] and there’s all sorts of mental health problems as there is in society. So, these adoptive parents have to work very hard to get a kid. In those days, you had to show you weren’t medically able to have a child yourself. And so, they go through all this effort.

Everything is hunky dory in infancy and childhood. But then so often by adolescence some of the kids would go off the rails, and these people just can't understand it. They said they did everything they could for their child. You tell them, well, but a lot of it is genetics, and you did the best you could. Maybe you made them happy while you could, but you're not responsible for their outcome.

But what people don’t really get is with adoptive parents, it's the same problem all parents have, but it's writ large because the adoptive parents are not at all genetically related to their kids. But the thing parents have to understand is their kids are only 50% related to them genetically, which means they’re 50% different from them genetically.

There's a great phrase that’s been attributed to probably half a dozen different people, but it’s that parents are environmentalists until they have more than one child.

Richard: Sure.

Robert: Because with the first child, you can always explain everything away environmentally. My kid's shy. Why? They’ll give you one of two answers: I took her out too much when she was young, or I didn't take her out enough when she’s young. That’s the problem with environmental explanations; after the fact, they can explain anything. But the neat thing about genetics is it predicts that kids in a family will be different.

Parenting is ... I was going to write a book. I actually had a contract with Penguin and a big advance to write a book, following up on Blueprint, about the genetics of parenting. But after about nine months of working on it, I realized I just can't write for parents. I mean, I thought Blueprint was low level to the point of being condescending; but as I give public talks, I realized it probably wasn't simple enough. But for a parenting book, you really have to write about, “Well, when Johnny was young ...” You have to do that sort of personal stuff, and I just can't do it.

Fortunately, because a friend of mine, Danielle Dick, just had a book come out last week called, I think, The Child Code or something, but it's a book that's very much about genetics and parenting. She can write in ‘parentese’ or whatever you call it. She's a mother with several kids too, so that helps.

Richard: Yeah. Blueprint is your only book, right?

Robert: No, I've written a dozen books over the years, but I stopped writing books, I don't know, about 10 years ago because I felt people weren't really reading books anymore. Graduate students came and they were doing a review in an area and they missed this classic book. But it's because everything's in terms of journals and what's recent. So, I don't think ... In your field, I think in political science there's probably more attention paid to books. But, boy, in the psychological science, books are really passe now. And I realized that you could make much more impact by writing highly visible articles, for example.

Richard: Yeah. I think that’s …

Robert: I just love doing books because, as you know, writing articles for journals, it’s very constrained. They have to be tight. Increasingly, journals are wanting articles of no more than 3500 words or 4000 words, unlike your field as well. But in psychological or biological science they want really short articles, and that's so constraining for thinking, in a way.

And so, what I love about a book is, for a year or two, it's kind of your anchor. You know, I write in the mornings, early mornings, very early mornings. It's always nice. You wake up and say, “I’m just going to do that.” My rule in the morning is I get up at 3:00. And so, my rule is that I only do things I want to do. So, if I'm working on a book or reading stuff, I don't let any of the real world intrude; grant reports or student papers or things like that. It's a lovely existence to have this steady anchor there. Whereas articles, every few weeks. Rarely do they take more than a month or so to write. And so, it doesn't give you that same ... I don't know what it is. It's an anchor, I suppose. You can see, I'm warming up to do another book.

Richard: Yeah. Well, I was asking because you said it’s to the level of condescension. I think for a popular book, I don't think that Blueprint was that simplified, but I can understand if you're used to writing for other academics or writing different kinds of books. But yeah, I never liked journal articles. I’ve moved away from them just because… It's not just the length. I mean, there’s a format. The literature review, I think it's overdone. You often get to point where it’s just citations for citation's sake. There's just a lot that I think is not pleasant about writing journal articles.

But to go back to the point about parents not having an influence but actually mattering. I mean, the first question, the first way parents matter, and I think this is so fundamental but we forget it. I don't know why we forget it, but the reason parents matter is because they decide whether to have children in the first place and how many children to have.

Robert: Absolutely.

Richard: If you were living under the assumption that every moment you spend with your child or every decision you make is going to be of earth shaking or fundamental importance to how they turn out, that's naturally going to probably lead to you having fewer kids.

Robert: That’s right.

Richard: People tend not to ... I don't know, people don't think in this way. I mean, my friend, Bryan Caplan, the economist, wrote a book called Selfish Reasons to Have More Kids…

Robert: Yes, I was just thinking about him, yeah.

Richard: Yeah, exactly. So, he thinks this way. I don't think this way, and I think this way. I just think most people don’t. To me it’s so obvious that if you have two kids and you're so busy with them that you can’t have any more, it would be better to just maybe lay off a little bit, take it a little easy and have a third. I mean, you matter for that person. I can’t believe ... Even if you thought environment was very important. Imagine how important it would have to be, to be preferable, to put so much investment into, say, one kid or two kids to just not have that third kid exist, or not even have that second kid to exist, right? Existence is good, right?

Robert: Yeah.

Richard: This is just so fundamental. I don't know why people don't think along these lines.

Robert: I agree. Also, I think it's important for parents to realize that if you take this genetic perspective, I think a big part of the enjoyment of being a parent is watching your child become who they are genetically.

Richard: Right.

Robert: That is really cool because you do ... Especially if you have more than one child or you experience a number of kids, the differences are extraordinary. If you’re alert to that, you do see that even from early in life your children are quite different. I think that's fascinating.

I love the idea of thinking of yourself more as a resource manager. Find out what they like to do and help them to do it. Increasingly, I think appetites, what they like to do, is equally important to aptitudes for something. And it’s a virtuous circle as well, you like to do what you’re good at. But parents should notice that and help them go in that direction because you love them, not because you want to make them into something. You just do nice things. You help people that you love. That’s the way the parenting relationship ought to be. I’m sure it’ll work out better for both the parents and the kids if more parents had that point of view.

Richard: Yeah. Do you have a sense? I mean, do you have a sense when the culture changed on the parenting issue? Was it the middle of the 20th century? Was it before that? Because I don't think people 100 years ago thought in these terms. When did this shift? Can we say something about how that happened besides just pointing to World War II? I mean, it's sort of strange because you had communism, right? And communism killed many millions of people and they were all blank slate, that's right. Stalin-

Robert: They were very much so, yeah.

Richard: Exactly. Yes, under Stalin, they repressed the geneticists.

Robert: Yeah.

Richard: So, it’s hard to just explain, World War II, Nazis were on the other side.

Robert: Yeah. I think it goes back, though, to Watson and the early behaviorists who are learning theorists, basically. Watson wrote popular parenting books that were very much behaviorism sort of guides to parenting. He had famous quotes about don't show your kid too much affection, only pat them on the head if you want to reward them for something good. He worked mostly with rodents, so they had very strict stimulus response learning approaches to this, of reward and punishment for example. So, there were a number of people like that going into the 30s and 40s.

Spock, Benjamin Spock, revolutionized things by saying, no, it ought to be more child centered, notice what kids ... It was a reaction against this behavioristic learning approach to parenting. But he didn't really talk about genetics, Benjamin Spock.

I think the pendulum has been swinging back and forth in parenting. And now, if you go to a corner bookshop and you look at the parenting section, the shelves of these parenting books, what bothers me is it's so bad for psychology because you get one doctor so and so who says, what you have to do is this and that. They, very authoritatively, no data behind it, very few of these books are empirically oriented. And then you pick up another book and it will tell you the opposite. That's going to be very bad for the field.

An economist ... Oh, I'm blanking on it. Oster, I think.

Richard: Yeah, Emily, Emily Oster.

Robert: Emily, yeah. Her book is great because as a mother she said, well, she’s an economist and empiricist and so she thought she’d look at the data and she saw how little empirical basis there was for what people were saying you should do. Her book is really great on that score, but it does end up saying ... There isn't too much you can say. I mean, she says, “Vaccinate your kid.” But beyond that there isn’t a lot you can say.

I think the point of it is that you can’t say what to do for all kids because all kids are different. Some parenting books say that, but genetics really provides a concrete basis for that. That's what Danielle Dick's recent book on The Child Code is about, thinking about these issues from a genetic perspective.

I don't know if that really answered your question about the history of it. There are books written about how parenting advice has changed over the years. But right now, it's just higgledy-piggledy. I mean, you can get every sort of perspective. There isn't like one dominant perspective now.

Richard: Yeah. That’s interesting because you talked about earlier that the funding situation is getting better, right? You’re able to go and you're able to get something funded. I went actually to Boulder, I was laughing when you were talking about it, for my undergrad. My major was in linguistics and I took classes in all kinds of departments. I mean, there was no influence of anything could be genetic. I had a cultural anthropology course where they told us the differences between men and women were all environmental; much less differences, things like intelligence or anything. And then you talked about the parenting books, and they're still so overwhelmingly blank slate as they're environmentalists in their outlook.

Are we basically in a place now and is this going to continue where you have the truth out there in academic journals and then books and people who want to know what's going on are basically going to be able to find out; but for the general culture, it's just sort of the good science is done in a box and parenting, and political science, and anthropology, and everything else just continues as before? Is this where we're headed or is there a way for these findings to break out of the box and have a major influence on the wider culture?

Robert: Yeah. Well, that's why I wrote my book Blueprint. I've taken a long view on it. I don't do social media, for example. I felt long ago that I wanted to spend my time doing the research and hoping that psychology would stay an empirical science and that eventually data would win out. And I think the data has, but as you point out, at that academic level.

There's big changes in the public reception. I mean, I find now, and I've given dozens scores of talks about Blueprint to public audiences, and there's no hostility now. Whereas in the past, people were really hostile. So, that's progress of a sort. The people I talk to, they say they just didn't know about it. I do get letters from people saying how it's changed their life to realize how important genetics is.

But you're absolutely right. My books certainly didn't break through to the public in that way. My hope, though, is with the DNA revolution and the ability to do DNA testing on your DNA or, increasingly, your children’s DNA, that really is going to make the difference. It will happen first in the medical area.

27 million people have paid to have their DNA testing done through these direct-to-consumer companies where you just send in some saliva and they do what we call a genome wide genotyping, they genotype millions of DNA differences and they put them together. First, you can predict the thousands of single gene disorders. But more importantly for psychology is we can put thousands of these little differences together in what we call a polygenic score to predict complex traits and common disorders. I think that's really what will make the difference.

For some reason, in Southeast Asia this is huge. China is already not just doing DNA testing, they're doing whole genome sequencing where you sequence all three billion base pairs of DNA, and that's the end of the story. That's all you inherit. They're doing that for half of the 15 million babies born every year.

Richard: Oh, wow. Is that in a government database? Who’s…

Robert: Yeah, that's a scary thing, yeah. But in Finland and Estonia, for example, if you go into the hospital, they'll ask if you want your DNA tested. They'll do it for medical traits, not just for single gene disorders though. They'll do it for cardiovascular disease because it's a no brainer in medicine that you want to move away from waiting till someone has a heart attack and then trying to fix it, which costs a lot of money and a lot of loss of quality of life to predicting and then preventing heart attacks.

DNA is the best early warning system we have, because the DNA with which you began as a single cell is the same DNA in all the trillions of cells in your body. You can get DNA from saliva, or blood, or skin, or any tissue because it's the same DNA. It doesn't change during your life, which means you can predict from birth just as well as you can in adulthood. What we know about interventions is the earlier you intervene, it's kind of a general rule, the more likely you are to prevent problems from occurring.

So preventive medicine is a very big deal as is precision medicine, which is the idea that instead of administering drugs, for example, on a one-size-fits-all approach, you try to specialize. You say, “this dosage, this drug works particularly well or particularly badly for people with this genotype.” We call it gene-environment interaction or gene by treatment interaction. That's another huge area of medical research. And so, I think without doubt, medicine will be the area where this happens first. But once you have your DNA tested, you can use that same test to get DNA predictors for any trait including psychological traits.

Again, if you take a long view on it, Francis Collins said 10 years ago he would be amazed if in 10 years we weren't doing whole genome sequencing for all newborns. Here we are 10 years later and they're still doing pilot studies at NIH because there's a lot of push back on it for reasons you could understand. Gattaca sort of reasons, if you know that science fiction film from 1997 which is sort of a genetic dystopia where you could predict ... A child's fate is kind of sealed at the moment of conception when they do this DNA testing, and they do embryo selection and all the things that people worry about with designer babies.

But again, I can see a lot of good that can come from all of this, and I think there's a lot of good that's come already. I think it's going to happen. It's not even going to happen, it is happening, when 27 million people have paid to do this. It is happening, and that's why I wanted to write the book to give people the DNA literacy that they need to discuss this intelligently and to try and get people to take it as a serious proposition without this knee-jerk reaction, oh, genetics, bad; environment, good.

But as you say, Blueprint wasn't the breakthrough that we need. So, I don’t know where it’s going to come from except I just have this vague notion that DNA testing is going to be the answer. And I do think, although people are very worried about direct-to-consumer testing, what I worry about, the NHS and the National Health Service in the UK is piloting this as well, DNA testing.

As I say, it's such a no brainer from a medical point of view. But they probably will only give people actionable information which for a lot of people is all you want. I mean, if I told you you're at a tenfold greater risk of having a heart attack by your 40s, it would get your attention.

And if I said, “Here are some approaches, low-tech approaches,” or getting into higher-tech approaches, I think you'd be game for that. And that's probably all some people want. But other people say, “Well, it's my DNA, I want to know everything. I want to know about even my risk for Alzheimer's.”

With 23andMe, I’m sure your audience knows about them. They’re the largest direct-to-consumer company. I think of the 27 million, 7 or 8 million are 23andMe. And they would actually provide information on one particular gene that increases your risk for Alzheimer's from about 10 to 15% which we all have at 85 years of age to about 60%.

And as medical risk goes, that's astronomical. I mean, it still isn't 100% but that's astronomical. And if I ask a public audience, “Would you want to know?” Because with 23andMe, there's like a triple lock on it, they don't just give you the information. You have to say, yes, you want that particular piece of information. And they give you some links to things to read about.

And they say, “Do you still want to know about this?” And then there's a third lock on it. But then, the bad part about this is it's only 1% of the population that would have the 60% risk. But if you were that poor soul with the 1% in the population and found out you had a 60% risk, they don't provide any follow-up service. They say, “Well, here's a link,” or that sort of thing.

So, I would hope that if you do it with the National Health Service or something, there would be much more support for you. But anyway, when I ask a public audience, “Would you want to know,” like your listeners, you could do this with 23andMe. You could find out, are you in that unlucky 1% where you have a 60-fold risk. And I find it splits right down in the middle.

And I don't know what the personality traits are behind it. When you ask the people who don't want to know, “Why don't you want to know,” and they say, “Well, duh, you can't do anything about it, it would ruin your life.” That's reasonable.

Richard: What age was this? This is you'll find out what age?

Robert: Well, at birth if you wanted to.

Richard: I mean, you said 16% to 60% by age or what was it?

Robert: I see. At 85, we all have a 10 or 15% risk which is I think ...

Richard: A very high risk.

Robert: Right. But then, it goes up to 60% if you have a double dose of this one apolipoprotein E4 it's called.

Richard: I think a lot of people assume there’s a good chance they’ll be dead at 85 anyway so that seems like a very, very long time off.

Robert: But the other half like me who say, “No, I want to know,” then ... some people think, “Well, that's really dumb because you can't do anything about it.” I said, “Well, you can do something about it. You can prepare for it if you knew you had that risk. You could set yourself up economically. And even socially, you can have support systems in place to cover that.”

And then I also think for me, there would be a very hefty dose of carpe diem if I knew I had that risk of losing my mind later in life.

Richard: Sure.

Robert: And also by getting these genetic predictors, it's much more likely that we'll find out ways to prevent it or at least ameliorate the risk. Because you don't learn anything much about dementia from studying demented people. I mean, their brain is just gone.

Robert: And you don't learn about alcoholics from studying alcoholics. If you’ve ever seen a postmortem brain of an alcoholic, you don't need a microscope to see what's wrong. It's like someone threw battery acid at it. But if you can find out how you can intervene to prevent these things or at least ameliorating the risk, that's the way it's going to go.

And with DNA, we finally have a predictor. And it's a causal predictor in the sense that there's no backward causation, which is unlike other predictors in psychology. Correlations don't imply causation, so x and y are correlated. That could be because x causes y or y causes x or a third factor causes both of them like genetics.

But when you correlate inherited DNA sequence with behavior, there's no backward causation, nothing changes that DNA sequence. So that makes it a unique predictor.

Richard: So you mentioned earlier, you said what they were doing in China, they were sequencing the genomes of half of newborns. You said Southeast Asia, are we just talking about China or are there other countries in that area who are doing similar things?

Robert: Yeah. Well, that's the Chinese national government. But in the rest of Southeast Asia, I mean Singapore, Hong Kong, Taiwan, for some reason, the hot thing now in direct-to-consumer testing is for parents to do the DNA testing of their kids. It's even marketed, believe it or not, as the go-to shower gift.

Richard: Yeah, wow.

Robert: And then there’s these companies then who on the basis of the genetic testing tell parents that they will provide parenting advice along the way that's personalized to their child's genotype. Now, that's way beyond the data. But again, that's where I think this could go.

Richard: Yeah, it's interesting. You say Singapore, Taiwan, Hong Kong, these are still all majority Chinese places. That seems like it’s the Chinese and Chinese overseas who are really into this stuff. What do you think about perhaps the way to break through our stupor on this, but maybe some kind of international competition if China takes these things seriously?

I mean, if you could potentially get to things like embryo selection and genetic engineering and just the biomedical knowledge that you derive from this technology, could that perhaps be a path that will make the West maybe take notice of genetics and maybe take it a little more seriously?

Robert: I hadn't thought about that. But you'd like to think people would do it from a pure intellectual point of view. You're absolutely right that nothing will get things going faster than competition. And already Chinese parents do, in America at least, seem to put a lot more energy into making their kids do as well as possible at school. And I think the interest in genetics might be part of that same academic orientation or whatever.

Richard: And it seems a bit contradictory because you want to know a lot about genes because they matter but you also think by really pushing your kids, you can cause them to succeed, right?

Robert: Yeah. Except that I think the way they market these parenting DNA testing things is differential testing. So, we don't have the genomic data for this yet but eventually, you'll be able to predict specific profiles of strengths and weaknesses. And so, it might help you to realize your kid is really good at math sorts of things or maybe more verbally oriented.

So I think that's the way it will go. And that's what these companies are pretending to provide, but the data just aren't there yet for them to do it. There's no regulation of these DNA direct-to-consumer companies so it's a real wild west and it's crap. I mean, it's going to lead to a backlash when people realize that these companies want their DNA. That's part of the big data thing. It's the ultimate big data in a way, but they're providing parents with crap information. I mean, the level of what they provide would never pass muster for a publication or scientific journal.

Richard: But that being said, I mean you just talked about ... I'm more inclined to not want to regulate it even if I agree with you that it's bad advice because we have books. We just talked about parenting books that are based on nonsense science and people buy those and they take it seriously.

Robert: Exactly right.

Richard: And so, I think government regulation can only go ... I think if you'd look at public opinion polls on these things, people are very scared of genetics and don't want to be really doing anything and I think just having a few companies that scam people but also do actually provide the scientific service and do build up the database and do provide you those resources that could eventually tell us something. I think that's the lesser evil. I think the laissez-faire attitude here might actually be best.

Robert: I agree completely. And especially when the bottom line here is it's your DNA.

Richard: Yeah, exactly. Yeah. That’s sort of decisive, right?

Robert: Yeah.

Richard: This is all fascinating. The technology is moving so fast even if our political and the social discussions around these things are stagnant and not being influenced seemingly by a lot that's going on. And people's personal lives like you talk about the women in Boulder getting pregnant by some random person. I don't think that happens anymore. I think that the people, in their own lives at least, that I think people become rational in their own lives before they become rational about politics.

Robert: Probably.

Richard: People will seek out the kind of sperm that you would expect them to seek out if they thought genes were very important.

Robert: Along those lines too, I’m struck by all the conversations going on about say the National Health Service providing DNA testing. And people are so careful and cautious and I can see the reasons for that. But what I want to tell them is people don't need you. They don't need the government. They’re doing this on their own.

And the more the government controls it and determines what's happening… I don’t think the government has as much power over people unless they try to shut down the direct-to-consumer companies. And I'm trying to shame them into providing decent data. Now, 23andMe, they don’t do these polygenic scores. These are new in the last few years, these polygenic scores. But that's where it's at in terms of psychology.

But the single gene stuff is very accurate from all these companies because high school kids could do it. It's not high-tech stuff anymore. There are just pipelines for doing these things. But with the polygenic scores, it kills me because it would take these companies no more effort to do it properly. But they’re just doing a shit job at it. It's just scandalous really that they would do that.

They just take a few genes and pretend that they’ve got a polygenic score, but it's like 5% as predictive as it could be if they had done it right. And then they also don't provide the information for interpreting it.

So I think what my goal is, I'm actually testing some of these companies through using students and stuff, and then comparing their results. And some people have done this but not at polygenic score level. And if you could just say, “Here's the way it ought to be,” and then companies ought to provide anchor information on height and weight, we know completely how that should work, how much variance you should predict and how to interpret it.

You have to tell people about effect size and things like that. So, you have to convey this information in a meaningful way. I'm a real Pollyannaish optimist sort of person. But I do hope, if you say, “Here's what it ought to look like,” and get a company to do that which I think we have one, imputme.com is a nonprofit run by this Finnish investigator, I think you quickly get other companies saying, “Oh, we better do this,” right?

Richard: Yeah.

Robert: Especially when it doesn't cost them anything. That's the killer.

Richard: Well, they might have some marketing. I mean, they might have some marketing. So I mean, you could give people their predicted IQ for example. I can think of good reasons why a business might not want to do that. So maybe they've done the market research and they’ve realized people sort of ... you give them a simplified message, you have this gene or not. And maybe the GWAS scores are a bit too complicated. And maybe that's a rational business decision. I don't know.

Robert: But no, because all the new companies, that's the whole thing, is these polygenic scores. For diets, for cosmetics, that's a huge area saying if you have this genetic profile, you should be using this type of skin cream, for example. Exercise is a huge area as well, fitness. So, these are all polygenic scores because single genes don't really count for that. These single gene effects are very bad if you have them but they're very rare. And they don't really contribute much to variance in the population.

So, my hope is I think we could have some sort of, what do you call it, like a quality mark system. That wouldn't be too difficult to do.

Richard: Yeah. I mean, it’s funny because, yeah, you could potentially have government regulates this or that and truth in advertising. Like for example, if you applied the standard saying you can't ... the government’s going to come in and you can't say things about predictions made from the genome that you can't overestimate how much we know and things like that. You have to think about what sort of government doing in other things.

If government is having an education policy that assumes the only differences between higher class children and lower class children is environmental, right?

Robert: Yeah.

Richard: The government is lying to people in the same way probably worse than the private corporations. So the fact that government can't figure that out makes it difficult.

Robert: Well, it wasn't clear because my goal was to keep it away from the government. And you know how there are these trade organizations that just set standards. If you go for a plumber or something, they have these little rating systems. So I think it might work better that way if you say, “Well, you get like a B rating rather than an A rating or two-star or three-star rating through a trade organization.”

And I really think that would work because they must realize that what they're doing is crap and that's going to be bad. It's going to bite them in the end because people like me are going to show that the data I get from some of these companies is worthless.

Richard: Yeah. Okay. Well, that’s an optimistic story. You’re certainly in a position to have some credibility to talk about what these companies are doing. So yeah, I mean I wish you the best of luck in that. I was just thinking when you were talking about the Chinese parents and the results that maybe tell you, “Okay, your kid is a little more math-inclined or a little bit more musically-inclined…”

If we get to the world where we know enough about genetics to predict that, then parenting might actually matter or adoption and twin studies might not be so good because maybe you actually do have the tools to actually shape children's outcome? Or maybe are we just not taking this stuff seriously enough because if zero really means zero and maybe there is a way to make a mathematically-inclined kid more into math, but maybe his level of math love and ability and interest is just going to sort of be what it is. Did you have any thoughts on that?

Robert: Yeah, very much. So I think the way genes work is to help us ... they don't work independent of the environment. If you've ever seen these really mathematically-gifted kids like one of my students has this foundation in Russia. For some reason, they seem to have a lot of mathematically-gifted kids. And if you see these kids early in life, they just live math. They joke about math. They talk math basically with their friends. And they have friends who are interested in math as well.

And I think that’s the way genes work to influence complex traits like mathematical ability. It's not hardwired in the brain. I think that's why I said before, it's as much appetites as it is aptitudes. And if you have this genetic propensity, then you select and modify and create environments that are correlated with your propensities. And that's where I think parents can make a difference as they recognize what their kids are good at and like to do, they can help them do that. And that's an environmental influence but we call it a gene-environment correlation. It's not like the environment overriding genetic propensities. Instead, it's going with the genetic flow if you see what I mean.

So I think that’s an important way in which the environment works. I talk about it as an active model of experience as opposed to the standard psychology approach to environment, which is an imposed environment. This comes back to the stimulus-response theory of early learning psychology where the environment's out there and it's what happens to us.

Very much like you're a rat in a cage and the experimenter’s out there and he decides to shock you or not when you do something. That's an imposed environment. But I think with genetics, we're talking about this idea of active involvement with your environment to create experiences. And I think even to perceive environments.

It isn't the objective environment that some observer records on a videotape. What’s important is your perception of the environment because that’s what’s experienced. So, anyway, this is a topic near to my heart because I think that's the way the environment works with genetics, whereas we don't ever study that because our measures of the environment are passive in the sense that we measure the environment out there as it happens to us.

Richard: Do you think that by focusing so much on parenting in the last several decades post-World War 2 era, we've sort of let society and government off the hook because we know not everything is genetic? We know for example say in the 1960s, the crime rate multiplied by several times. We know out of wedlock birth rates are much higher than before.

So, that wasn't the result of a genetic change, something was happening in the environment. It probably wasn’t that parents had treated their kids differently, but there was something we as a society did that changed the environment and made people different than they had been in previous generations. By focusing on parents, do we just let society, let some ideas, let government off the hook for problems that have happened that aren’t actually the fault of parents but are fault of something else?

Robert: Well, that's an interesting idea. See, I think in terms of individual differences and the way I think of the ... you're talking about mean secular changes, average changes in a population. And the way I look at it is that when we talk about things being heritable, we're talking about it in the context of a specific environment.

We’re describing, given the range of genetic and environmental influences, to what extent are genetic differences between people important in that environment at that time. And if you change the environment, this can all change because these are descriptive statistics just like means and variances describe a particular population at a particular time.

But furthermore, what I see is when the environment changes like there's moderate genetic influence on alcoholism, for example. But if you have a society where there's no alcohol, then you're not going to be alcoholic. Whereas if you have an environment like the college system in the US, it’s like trying to find out who has a genetic propensity for alcoholism by almost forcing alcohol on people.

So say it's the alcohol, you go from the prohibition which didn't really prohibit alcohol. But if you made alcohol more available then the people with the genetic risk are more likely to become alcoholic, as well as the population average alcohol consumption going up. But it is an important distinction that the causes of average differences like these secular changes you're talking about are not necessarily related to the causes of individual differences.

And the classic example of that is when the Japanese came to America. In one generation, their kids were two inches taller than the parents. So that clearly can't be a genetic effect, it has to be environmental. Nobody still knows exactly what it was. But the heritability was just the same. So, although the kids are two inches taller on average, the tallest kids are from the tallest parents. And that's genetic.

Richard: Yeah, I understand the distinction there. I was just thinking in terms of how we think about these issues. So I mean, I think that we ... like for example, you'll hear people blame these changes in the mean based on parenting. So, there's this book by Jonathan Haidt and a coauthor talking about helicopter parenting. And so, you can't disprove it I think because we don't know about shifts in parenting. Maybe there are shifts in parenting can change something.

But within the society, the genetic influence is similar. But I think our prior on that has to be ... it’s probably whatever happened in the last decade or two or the last several decades is probably something else besides parenting. Do you have a similar intuition there? For example, if you show that for example, depression and anxiety have gone up in the last 10-20 years, as a first guess if we're investigating the causes of that, parenting probably should not be the first thing we look at or our prior should be, it's probably something else.

Robert: Jonathan Haidt says the social media.

Richard: Yeah, exactly. But he also writes about parenting, too. So, that's another potential explanatory variable. And the question is does behavioral genetics tell us anything about the plausibility of that?

Robert: I think not. I mean, I really do think it's important to emphasize that the causes of these mean differences can be completely different. So, a trait can be very highly heritable like height for example. And you could change it drastically simply by messing up kids' nutrition.

Richard: Yeah. So, it's a plausible theory I guess that all parents say in this generation compared to the last generation all started doing something or started behaving in a way that the previous generation didn't. And that was one of the influences of shifting the mean in say anxiety or whatever. Do you see what I'm saying?

Robert: Yeah. Well, I mean, the first one I would make is that heritability doesn't really speak to the extent to which something can change on average like that. And it's also very hard to pin down the cause of a mean difference because, yeah, social media began about the time that the increase in depression and anxiety especially for girls happened, but there’s a lot else that happened then, too. But I find it plausible.

But I guess the point I'm making is it’s very difficult to have the killer data, the definitive data that proves a cause of an average mean difference, whereas genetics is very powerful for studying the genetic and environmental etiology of individual differences.

Richard: Yeah. Okay. So, I think for our final topic, we touched on a little bit about the political implications and the social implications of the behavioral genetics research. There's two books by liberal hereditarians that came out of the last year or so, one by Paige Harden and one by Frank deBoer [note: actually Freddie deBoer]. Have you read either one of those books?

Robert: Yeah. I know Paige Harden's book, but what's the other one?

Richard: I think his name is Frank deBoer. He's a researcher. He knows about education. And he wrote specifically about education itself. Have you ever heard of that book?

Robert: Well, there’s another book that was very famous in the last years about education. It wasn't that author though. So you'll have to tell me about that book.

Richard: Okay. Frank deBoer, it was mostly about the education system. And he identifies as a communist but is a hereditarian and was talking about the genetics of intelligence.

Robert: Is that the book that had “junk” in the title? What's the title of that book?

Richard: “Junk” in the title, I'm not sure. I forget the name of deBoer’s book. But we could talk about Harden. I’ve not read the book. I’ve listened to her on a few podcasts. I’ve read a profile so I know a little bit about it. What did you think of the book? What are your general impressions?

Robert: Well, do you identify as a political scientist or what?

Richard: I identify as an independent scholar. I’ve written about how I dislike these sort of artificial divisions between fields. So, I sort of ...

Robert: No, I agree with you there. You were saying though that your education was ...

Richard: My background is political science. Yeah, my PhD is in political science.

Robert: So, I don't know if you’ll agree with my view on this. It’s an old-fashioned view. I have spent a lot of time in my career trying to keep science separate from politics. I always try to say, there's no necessary policy implications of finding genetic influence.

Now, I don't know if you agree with that. But I can give you right wing examples of what to do with it or left wing. I think it does depend on your values and you'd hope that better policies follows from knowing more. But as I get older, I get more cynical about that. I think policymakers often use the science when it fits what they wanted to do anyway, rather than the data driving the policy.

But Harden is explicitly doing the opposite. She’s trying to say, “I want to convince the left that genetics is not their enemy, that there's reasons for them to understand why genetics is important.” And when she first was thinking about doing this three or four years ago, I told her, “I don't think so. I don’t think you're going to convince people of that.”

And given the culture wars that have happened since, I think what she's done is stuck genetics into the culture wars to a greater extent than they were already. And she’s getting clobbered from both sides as I would have predicted. But the basic genetic argument is much like Blueprint, just saying genetics matters. And there's a lot of data that support that.

But I don’t know. I just stay away from the culture wars and as I say even from social media because I ... I’m sure you're very much involved in it. But man, I find Twitter is such a cesspit. [laughter]

Richard: It is. You’re making a smart decision there although it's great to sometimes connect with people. There's some smart stuff on there, too. But yeah, the political implications ... I mean, yeah, you can have different value judgments and you're right that politicians will often just seize on whatever supports their view anyway.

But … it can tell you what’s true or false. So if your ideology tells you you’re going to have equality of outcome, you want a world where people from the lower classes and the people from higher classes produce offspring that are equally likely to be Nobel Prize winners or equally likely to become professors or entrepreneurs or billionaires or whatever. You just can’t have that world.

So I mean, even if we can have whatever values we want, but taking genetics seriously does mean we have to rule some things out, doesn’t it?

Robert: Well, I don’t know. I’m quite interested in using genetics as a tool to do the opposite of what you're talking about. Do you know that most of the brightest kids of the next generation don't come from the brightest parents? They come from parents of average IQ.

Richard: Sure.

Robert: And that’s because there are very few very bright parents. They probably don't have as many kids on average, but there’s regression to the mean. So, if PhDs have an average IQ of 130, if two PhD people marry and have kids, the average IQ of their kids won't be 130, it will be 115. And that's because it's 50% heritable.

If it was 100% heritable, they would have an average IQ of 130. And if it was 0%, heritable, they'd have an average IQ of 100. So it's in between those two because it's 50% heritable. But still, that's a very small number of kids compared to the kids from parents in the middle of the distribution.

And in our study where I have a DNA of about 15,000 kids in the UK, kids in the lower SES from parents who didn't go to university for example and meet criteria for free school meals and stuff like that, there's a wide range of distribution of these polygenic scores in those kids. And I like the idea of using DNA to select kids who wouldn't otherwise meet their genetic potential because they're in an environment where there's no motivation to go ahead academically.

Richard: Well, I mean, that's fine. I mean, that is a form of a vision of how genetics can be used that some people can clearly find appealing. I know you don't want to get deep into the culture wars so you can deal with this question however you want. But if your basic idea, you understand for example that yes, there's more average parents than intelligent parents, there's going to be more geniuses produced by average parents than intelligent parents.

But what I think what people on the left do is they want equality of outcome between the parents earning over $100,000 a year and the parents who are high school dropouts earning under $20,000 a year. And at the very least, even if we have the best tools in the world, you're probably not going to get equal outcomes, right?

Robert: I really agree. Yeah. And it’s what bothers me about Harden's book. It’s I don’t think very clear on it, but it does seem to me that people are substituting equality of opportunity for equality of outcome. And with genetics, there isn’t going to be equality of outcome unless you go for the ... I guess by equity, isn't that what people really mean that they want outcomes to be equal?

Richard: Yeah, practically. I think they infer that there was no equal opportunity from differences in outcome between groups. So, maybe they'll say, “We don't have equality opportunity because there are more men in engineering or there are more [kids of] rich people who turn out to be rich than the opposite.”

So, the genetics pierces a hole in that argument. You can’t keep making that argument if you take behavioral genetics seriously.

Robert: Yeah. Well, I'd have to agree with you on that. I do think people have to recognize that there are genetic differences as teachers do. I’ve done surveys of teachers and they're not taught anything about genetics, but you can’t teach 30 kids in a classroom and not be aware of genetic differences.

You give the kids the same sort of educational curriculum. But some kids, you just have to stand back and they go roaring off. And other kids need a lot more help to get ahead. So, we’ve got to recognize that not all kids are the same. As much as academic achievement and intellectual ability are valued in our society, I think there has to be room for more recognition of diversity of talents. Like I think we need more plumbers and carers than we need professors.

Richard: Sure, absolutely.

Robert: And I do think in England, there's a move towards this as there has been in Germany and Switzerland for a while towards more ... we used to call it vocational training, which has a bad name. But in Germany, you can go into an apprentice-like system where you get rigorous training. But you also get a job and you get paid while you're doing ... and you have a job when you get out.

Whereas, a lot of kids in university now are taking courses that just aren't going to lead to jobs. And they’re going to be flipping hamburgers which can’t be a great thing either. And in some ways, now, this is really Pollyannaish but I do think of ... well, it’s almost embarrassing to say it but that universities aren’t just factories producing good workers in areas.

Part of it is to get people to learn stuff and learn to learn and to enjoy learning. And you know what I mean? I’m sure you've thought about these sorts of things.

Richard: Yeah.

Robert: I dislike the bean counter approach to university education. And I love it when you get undergraduates. They’re just thrilled to be learning about things. And I wish we had more of that.

Richard: Yeah, I agree. And I think the idea that the point of education is to ... like we talked about parenting, the point is just to get some outcome. Yeah, I mean, it takes away from the joy of just doing the thing that is actually valuable. I think that that’s a great point.

So, this has been great, Robert. And so you talked about how you’re not going to do the parenting book? Can you talk about what you’re working on now, any future books or any promising areas of research?

Robert: Yeah. Well, it’s just so exciting, the DNA revolution and there's new stuff coming out all the time. One thing I’m interested in now is there's just been one of these genome-wide association studies of sibling differences. And I think one of the hot areas is that people are going to recognize that kids in a family are 50% different genetically.

And DNA is one of the best ways of getting at that because most of our family risk indicators like if you had a father who was alcoholic, you'd have five-fold greater risk of becoming alcoholic but so would your brother. Whereas with DNA, you can predict that, no, you are the one that will have much higher genetic risk than your brother.

So I think that's an area of research that just interests me particularly, why are kids in the same family so different. So that's just one example of a lot of different things we’re doing. But just one quick thing is I'm at the Institute of Psychiatry, Neuroscience and Psychology in King's College London. And one of the developments of the DNA revolution is it's really going to get rid of diagnostic categories, this whole idea that you're either schizophrenic or not or alcoholic or not.

And one of the weirder things that’s come out of the DNA data is what we call little p. There's a general genetic influence on psychopathology and many of the genes that affect bipolar depression affect schizophrenia, affect ADHD. A lot of the genetic influence on psychopathology is very general in its effect. Whereas the diagnostic approach assumes that they're etiologically distinct disorders.

And the other bit of this is that there's a disorder at all because the DNA is normally distributed. It's not like there's any breakpoint. It's not like there's a single gene that's necessary and sufficient for any of these disorders like schizophrenia. There's thousands of tiny DNA differences so that there's no genetic evidence for a cut point there, which means we all have thousands of genetic risk factors for schizophrenia. But it's quantitative, not qualitative. It's a matter of more or less rather than either-or.

So, I think this is really going to revolutionize psychiatry, which I think has been held back by the medical model which assumes that there's a simple single gene or single cause. Like with COVID, it's caused by SARS-CoV-2 virus. You don't get COVID unless you have the virus. And supposedly, if you have the virus, you get COVID. We know that's not true. There's a lot of people who are quite asymptomatic.

But that's where the medical model works. When you have a simple cause whether it's environmental or genetic, then you want to diagnose, you want to make sure like in the early stages of COVID who's got COVID, is this a cold or is this really COVID, and what are the symptoms like the loss of the sense of smell or something like that?

So, it's really important to diagnose it because only then can you see what the cause is. But with common disorders and complex traits, there are no simple single causes whether genetic or environmental. So, I find that very exciting, too. I think this is really going to be the nail in the coffin of the diagnostic classification scheme which comes from the medical model which I think has really held back psychiatric research.

Richard: So, would it be an accurate comparison to say that there's emerging evidence so there's like ... I think a lot of our listeners will be familiar with the g factor of intelligence, that there is some kind of common factor to different kinds of mental illnesses that people can be graded on or a spectrum that people can be placed on? Is that sort of the idea?

Robert: Absolutely. And that's why it’s called little p, it was directly analogous to little g, the g factor, which is the same thing. You think of like memory versus spatial ability versus vocabulary. There are so different cognitive processes, yet much of the same genes involved in memory ability, individual differences in memory, are the same genes involved in spatial and verbal ability.

So, that general genetic influence is what we were talking about with g. And what we're finding in the last few years from molecular genetics is the same sort of thing in psychiatry, that a lot of the genetic influence in psychiatry and different psychological disorders are the same genes. There are also some specific ones. That's not surprising because people thought that these were completely etiologically distinct.

But what's exciting and interesting is the idea that no, that a lot of the genetic influence, maybe half, is general. And so, there's an interest in trends, diagnostic treatments, because if the same factors are causing many different disorders, then perhaps there are treatments that will work across different disorders. So, it's a whole new way of thinking about psychopathology.

Richard: That’s fascinating.

Robert: So, it's just all very exciting. And this is what happens I think when you bring a new area like genetics to a field like psychology who for a century had ignored genetics.

Richard: I know this is talked about a little bit in Blueprint, is there a review article or a book that you’d recommend to people who are interested in the p factor, so to speak?

Robert: Yeah. Well, it's a number of new articles. There's no book yet out in that area. But if you just Google “p factor,” you'll get the key articles. I think one of the best is a review article by my colleagues Avshalom Caspi and his partner, Terrie Moffitt. But really, just Google the p factor and you'll get a number of these papers.

They're still in the scientific literature. I don’t know that there's any sort of presentation for the public yet because it's rather new, all of this.

Richard: Yeah. Well, fascinating. I mean, Robert, your love of science and the avenues that genetic research has opened is infectious. So, great talking to you and I wish you the best in your future research.

Robert: Thanks. Terrific talking to you, Richard.