Robert Plomin || How DNA Makes Us Who We Are

the podcast. Doctor Poulman is Professor of Behavioral Genetics at the Institute of Psychiatry, Psychology and Neuroscience at King's College, London. He previously held positions at the University of Colorado, Boulder and Pennsylvania State University. He was elected a Fellow of the Academy of Medical Sciences and of the British Academy for his twin studies and his groundbreaking work in behavioral genetics.

The author or co author of many books, including Gas for Genes, The Impact of Genetics on Education and Achievement with Catherine Asbury, and most recently Blueprint How DNA Makes Us Who We Are? Robert so great to chat with you today. Thanks. I look forward to it. Yeah, it's an honor. I mean your research was foundational for my studies in the field of human intelligence, and you're one of the top should we say founders the field of

behavioral genetics. Would you consider yourself a founder of that discipline? No, I mean, you know, most people consider the founding like Scotton Fuller's book in nineteen sixty. So I was part of the second generation. I think, you know, the first generation was people like John de Frize, and people came out of agricultural genetics and really animal husbandre whereas I was,

you know, a real psychologist. I was trained as a psychologist and I got into behavioral genetics just by chance because I went to the University of Texas at Austin, you know, where they had the first behavioral genetics program. How don't you know that story about Gardner Lindsay No, past president of the APA, and for his presidential address he gave a talk about sort of genetics and evolutionary stuff.

But he did the early work in the fifties with inbred strains of mice and kind of looking at genetics with Marty Mansovitz. So with the Sputnik era. Texas tried to recruit him from Harvard Gardner Lindsay and they said, we'll give you whatever you want. He says, right, well, I'd like to have the first program in behavioral genetics at the University of Texas at Austin. And he could hire anybody he wanted. So he hired just about everybody

in the world who was doing it then. This is in the late sixties, people like Jamduel who studied fruit flies, del Tiessen, who studied mice. There was only about a dozen people in the world, and he got about six of them or so. So it was really amazing. And I went to graduate school at Texas not because of

that program. I didn't even know about it, but you know, they had one of those I don't know if graduate programs in psych in the US still do this, but they had a core course set of core courses in the first two years. Really fortunately I did school they do. Unfortunately.

I think they were good in a way because they made everybody take the same courses clinical perception learning, you know, personality, and at Texas, uniquely, behavioral genetics taught by all these phenomenal people, you know, not just Gardner, Lindsay, but John Lowland, I certainly should have mentioned him. All those guys they just taught some lectures on this course, and so I had to take this course and forty students in the class,

and it completely blew me away. Yet thirty nine other people, you know, didn't hit them at all. And I often wonder, you know, what is it that, Why did it affect me and not anyone else? And I really don't know the answer to that. Isn't the answer your DNA because these needs are obvious based on your research. No, I'm extraordinarily interested individual differences my whole life. I have always wondered why am I so interested in individual differences? I've

wondered that. Now I'm interested in all of the causal factors that predict individual But I have always been I remember, you know, being five six years old and on the playground and just massively curious, why is that person able to go in that jungle gym and swing on it or like I can't you know, when I try, I fall and I, you know, get hurt very bad. And

I was really curious about that at age five. So yeah, I wonder if there is a genetic contribution or influence to the extent to which you're interested in studying the science of individual differences. Is it lucky though, that you know, you kind of find out what you like to do. Yeah, because I think you only do well at what you like to do. I mean, we could probably do okay at a lot of different things, yeah, including just making money,

you know, in business or something. But it's really a tremendous joy in life to find something you really love, even though when I talk to people about it, very few people really like you and me. They really don't know why it is they like what they like, but you know that you do well. Yeah. I think that's

a really good point. And I actually just came across the study about five minutes before I had this conversation with you, So this is actually a really good timing, this study showing that like the single best predictor of productivity, You know how everyone has all these like ideas for what is productivity or what causes productivity? The single best predictor of pro activity was just simply how much fun

do you consider the task? You know, there's all these other proposed hypotheses and you know, ideas and hack productivity hacks, which I'm putting quotes the word hacks and quotes. You know, maybe at the end of the day, that is important, and that does seem to relate to a central thesis of your new book of going with the green, not against the green of your nature, and it seems to

be a core theme of your book. And I'd love if you could outline for our listeners a little bit how you arrived at this conclusion, some of the research you went through. I mean, you've had a career of forty five years and you said that you've been willing to write this book for thirty years. So my first question is that first fifteen years, what happened there, you know, that transformed you to then you know, after the fifteenth year, you decided, well, I really kind of want to write

a book about this. And then if you could just go through some of the seminal studies that you conducted after that, after you lay that out, then we'll go through the five major discoveries. But first, if you don't mind, just tell me a little bit about the methodology. Well, yeah, as I say, in the second year of graduate school at the University of Texas at Austin, I was exposed to this core course in behavioral genetics, and I just knew at that point that's what I wanted to do.

And I still don't know why, but I really did. I mean, I hadn't had genetics before. I guess part of it was maybe personality, you know. At that time, well, I was everything undergraduate, you know, I was just taking undergrad with courses that fit in with my work schedule. I was working full time while I was in university, and I was in film in English, and then a long time in philosophy. But then I had this magic moment in philosophy where I was at the Paul University

in Chicago and they were into phenomenology. So for the third time I was hearing about deskness, you know, the idea of phenomenology. And I kept getting in trouble in philosophy because I kept saying, well, how do we know what this guy argues is any better than what this guy argues? And I kept trying to come up with testable hypotheses and I was kind of stonewalled on it. And then I just had the realization that if you can test it, it's no longer philosophy and it's psychology.

So I just walked out of class and that was it. I became a psych major, which you know, in the States you can do you can change your major, as I did four or five times. But that was really kind of an important moment in my life, realizing I'm just kind of an empiricist. I just want data to solve problems. I don't want to just argue about things.

Then I happened to go to the University of Texas at Austin and they were you know, I knew that's what I wanted to do, and so I got involved a little bit with John Lowland and Joe Horn who were working on the Texas Adoption Project at that point. But my supervisor was Arnie Buss, who is one of those guys who if they weren't so smart, they'd be locked up, you know. I mean we had some incredibly

difficult times. I grew up in a family where it was impolite to argue, whereas Ernie Buss would start conversations like, God, I didn't know you were so stupid. I mean, how could you say something like that? You know? Was that n Buss's father? It is indeed? Wow, And David Buss got to run to that too. I could tell you some stories there as well. But Arnie, you know, it's sort of like the Marines. You're not sorry you did it, but you wouldn't do it again maybe, you know, But

it was a very important you know. I learned to be tough and I could give as well as I got, you know, even in sort of bare knuckles verbal fights, you know. So that was a good experience. And so Arnie was into personality at that time, Ernie Boss he wrote books on aggression and that sort of thing, and so I was doing work in personality. I thought what would be cool is to study what at that time

was called temperament. Was trying to find the more genetic aspects of personality, and so I did my dissertation on that, a twin family study, that sort of thing. And so for quite a while there I did work on personality, including observational twin studies, you know, where we go into the home. So the new thing was I thought, let's not just do self report, how about parent ratings, how about observers going in the home and looking at kids,

you know, getting different. I was just worried that everything in personality seemed to be heritable and maybe that's a self report sort of bias. I thought, you know, this is back in the early seventies. So then I did observational studies in the families with David Rowe, who was my first student when I was at the University of Colorado.

That was kind of cool. He was in his second year and he was in social psychology, and when I gave an initial talk on behavioral genetics, he had that same experience where he said, I'm not doing social psychology, I want to do that individual differences genetics, that sort of thing. So I became his sort of shadow supervisor and we did work together and that was great. You know, David did a lot of important early work. David Rowe Do you know him? Do you know of his name?

I do know of his name. Yes, yeah, I've seen as a co author on various papers. Yeah. Yeah, he died, you know, pancreatic cancer. It seems like my best friend seemed to die of that. David Folker also died of pancreatic cancer. So anyway, that was all great in terms of getting going. But then I decided personality measures even parent reports observer reports, the measure which just aren't as

well conditioned as cognitive abilities. So that's when I got into I just kind of made a conscious decision to get into cognitive abilities, and I began the Colorado Adoption Project, which is a study of two hundred and fifty adoptive families in two hundred and fifty match non adoptive families, where I had tested the biological mothers of those adopted kids myself when I first got to Colorado. Tell me

if I'm jumbling the story too much. But I was in the University of Texas seventy to seventy four, got my PhD. I was going to stay there. They were even thinking of hiring me as an assistant professor. But then, as an example of non shared kind of random environmental influences, someone at Colorado, at the Institute for Behavioral Genetics committed suicide in June. So John Lowland got a call from

Jerry McClaren at Texas. At in Austin, Jerry McClaren found at the Institute for Behavioral Genetics, and Jerry asked John if they had anyone who could fill this slot, and so John said, oh, yeah, We've got this guy. Robert Plumman he'd be great, done deal. You know, they just said, well, why don't you come and visit. But you know, it wasn't like today. I mean there was no advertisement, there was no you know, no anything. So, I mean, it

was the ideal job for me. It was a joint appointment in psychology and at the Institute of Behavioral Genetics, and you know, it was phenomenal. That was the only institute for behavioral genetics then in nineteen seventy four. So I decided I'd do something different, having seen the Texas Adoption Project and realizing that since the forties and fifties there really weren't many adoption studies. There were a lot

of twin studies. So I thought it would be good to use this very different design of the adoption study to study behavioral development. And that's what the Colorado Adoption Project was about. So it took three tries to get an NIH grant because back then it was not a cool thing in psychology to be studying genetics. Students nowadays find it hard to believe that it was dangerous professionally and even personally to study genetics in psychopagical Well, well,

I just want to pause a second. To reflect. It seems like things are actually reversed. It seems that it's not terribly cool if you're an environmental researcher these days. Yeah, but I always say that genetics provides the best evidence of the importance of the environment. It's just you know, it's very difficult to find out what those environmental are. We'll get to that. No, No, we'll get to that. Yeah. Yeah.

Can you describe a little bit the specific methodology that based some of your conclusions in the book on in the sense like treat our audience Some of our audience listeners as not. I mean a lot of them are not psychologists. Right, So when you say, when we talk about the twin methodology, could you just like the twin separated at birth sort of paradigm. Could you describe the paradigm a little bit? Okay, Yeah, Now I assume that people following you would be more newer, but not all

the necessarily. Oh well, yeah, when you say twins, people think of the twins were apart. Did you see this film that's come out It has it's about to come out in the UK, Three Identical Strangers. No, No, It was released in the States in June. I understand. It won a special award from sun Dance, the sun Dance Film Festival. But you know, it's the story of those twins separated by the psychiatrist Neubauer in New York. And you know, these are the Eddie and they were identical triplets,

separated in the same adoption agency in New York. And you know they got together because one of them went to university in upstate New York and everybody kept calling him Eddie, how are you Eddie? And he said, I don't know you. And then the next day he found Eddie and it was like looking in the mirror, and they pieced it together that they were both adopted from

the same adoption agency in New York. And then because of that publicity, a third one came up and said, oh my god, you know, I'm an identical twin with you guys too. So they're phenomenal. It's such a powerful design. It's so dramatic. You know when you see these identical twins.

When you see identical twins, we're together. I mean, that's pretty dramatic too, But these identical twins, we'red apart, and they find it's like looking in a mirror, not just physically, but they came to realize how similar they are and everything in personality. You know, there's differences, but it's like variations on the same theme. And for example, you know, they were all interested in kind of different things, like

one was I think, going to be an engineer. But by talking to each other, they all realize they really have a strong artistic drive. And they're now actually all in acting school because they've kind of just decided that's really what they want to do. So I think that's really dramatic. So that's a great film to kind of recommend Three Identical Strangers. I can't wait to see it myself. Yeah, guess what people think about when you say twins identical

twins apart? I did do with Nancy Petterson and Jerald mcclaran a large study, the largest study of twins verd apart in Sweden, because unlike the Minnesota study, which is what I was describing, you could use systematic records. There was always the question in Bouchard's twins verd apart study, maybe these twins, like the ones I just described, identical twins vert apart, maybe they got to know each other

because they're so unbelievably similar looking. And you know, maybe there are identical twins verred apart who aren't so similar, but they don't know about it because they're you know, they're not so similar. So we did a large study of twins verd apart in Sweden because they have excellent records. There are no phony birth certificates as there are in the US. You know, your biological father on your birth

is your biological father. And you know in the States they put in the adoptive father on the birth record as if he's the real father, for example. I don't know if they still do that, but they did it. I was there. So in Sweden we could get these a systematic study, but we get the same results, you know, showing everything's at least fifty percent heritable. But when I went to Colorado, I decided there's enough twins studies, Like there was the Louisville Twins study, and that's studies of twins.

We're together. You know, one percent of all versa twins, one third of them are called identical twins monozygotic a single fertilized egg, so they are clones. In fact, they're more clones than clones because if you or I were cloned. We took a cell from our body and made it omni potent or whatever that's called, so that we could or a stem cell or something, so that we could

use it to create a new individual. That individual, our clone with the same DNA as us, would be raised in a different woman, unlike twins who are raised in the same woman, and they'd be in a different era, you know, they grow up in trump Land rather them in the Swinging sixties like me. So identical twins are actually more clones than clones. And then the other two thirds of twins are I said, one percent of all births are twins. One third of those are identical twins.

The other two thirds are like any brother and sister. They're fifty percent similar genetically, but they're born in the same womb at the same time, grew up in the same family in the same era. So, if the twin method is simply saying that, if it's a really simple design at some level, a biological experiment in a way quasi experiment, if a trait is heritable, you'd have to predict that the identical twins, who are twice as similar as fraternal twins, would be more similar for the trait.

So that's the twin method, and there were quite a few of those studies around. The Louisville Twins Study was a study begun by Steve Vandenberg, who was at the University of Colorado when I went there, and then carried on by Ron Wilson. Had interest in particularly in cognitive development in twins. So I thought there were enough twins studies, and based on the Texas Adoption Project, I wanted to

do an adoption project. So I talked to John DeFreeze about it, who's always been my closest colleague, and he was very encouraging, you know, he was a professor and I was there as a new assistant professor. But some people, including John, said, this is like the classically bad idea for an assistant professor to say, I'd like to do this long term, longitudinal study of adoption, you know, and we to get tenure before you can do yeah, which is not very good for long ter studies. Tweak. Yeah,

that's right. So I'm always an optimist, though, and somehow I didn't. That really didn't worry me at all. But I spent the first three years trying to get a grant for this, and you know, it was at a time when nobody would get grants for genetics. Genetics was

really not cool in terms of psychology. So for about three years I was in Boulder and that's about what thirty miles from Denver, and that's where I found these adoption agencies that were very keen to participate in this research because our basic questions of nature and nurture are sort of applied questions in terms of adoption agencies. You know that adoptive parents sort they want to know, you know, how important is genetics on important is environment. So anyway,

they were very cooperative. But because I had no money, I wanted to test the biological mothers because in those days, and this is the early seventies, so it's the end of the swinging sixties, and it was before birth control was available to unmarried women, and it was before abortion was legalized. Today we heard about Brett Kavanaugh and you wonder,

is Roe V. Wade going to survive. But back then abortion was legal, and so many young women who were pregnant went to adoption homes they called homes for unwed mothers, and they you know, in a different city and they would have their kid and then leave the kid for adoption and never have any contact again. So unlike adoption today where there's often communication between the birth parents and

the adopted parents, that didn't happen back then. So here you've got these women girls I'm thirteen to twenty eight, who were in the last trimester of their pregnancy living in these homes for unwed mothers in Denver, and so I spent my weekends driving from Boulder to Denver and testing them. I had three hours to test them, and then I could never have contact with them again because part of the deal was anonymity that they sort of wanted to give their baby up for adoption and get

on with their life. So they were my only problems. I couldn't get out of there because they were so bored. They were thrilled to be taking these tests and have someone taking an interest in them, that sort of thing. And so then we've studied the idea of an adoption study A twin studies like a biological experiment where you have two types of twins, one one hundred percent similar genetically pair by peer, the other fifty percent similar. The

adoption method is like a social experiment. We know that nature and nurture go together. When you say schizophrenia runs in families, environmentalists had no problem with that. You know, that's nurture. But we say, well, it could be nature, and now we know it's all nature. What runs in

families is nature, not nurture. So the adoption design separates nature and nurture through this social experiment by studying parents who adopt these children and give them their homes from early in life, so they share family environment nurture, but they're not genetically related to the kids. And then you have adopt biological parents who relinquish the kids for adoption at birth. They share nature genetics, but they don't share

that post natal family environment with the kids. And then in that I was proud to think that in the Colorado Adoption Project, it would be good to have what we call control families match to the adoptive families. These are families who, you know, there's no good word for it, not regular families, but parents in offspring who share genes and environment, you know, the usual sort of family environment.

So I finally got funding after the third try in the late seventies to follow these kids and their families and then other kids born into those families, and we've been funded at IBG. I'm only a co investigator on it, but we've been funded to follow them up at forty years of age, which is pretty cool. Yeah, that's sort of how my early career started. In the Colorado Adoption Project, we tried to study everything because we knew there wouldn't

be other studies like that. And what I've learned is when you try to do a study of everything, you don't really do a study of anything, you know, because you can't study anything well enough if you try to cover the waterfront. But we did do a lot of interesting novel things, and one of those was to put

in environmental measures of the home environment. There's this measure called Home Home Observation for Measurement of the Environment, and it's probably the most widely used observational measure of infant

and early childhood home environments relevant to cognitive development. And so we put that in the Colorado Adoption Project because I'm interested in development, the interplay between genes and environment in development, but then also to get a handle on the environment rather than just always treating it as the non this component of variants. That's a residual from what

you don't explain from genetics. So one example of what came up that was quite shocking is when I looked at the data for adoptive and non adoptive siblings, we found evidence for genetic influence on home environment. You know, like the home is one of the better correlates of cognitive development, and it's a measure of the environment, right, so it shouldn't show genetic influence. Like TV watching It

has a heritability, right, something like that. Yes, it's just sort of that thing, did you say, TV wh Yeah, yeah, television watching. That was surprising when I saw that as a pretty that was also in that study too. But what we found is that all these measures of the environment in the adoption design showed genetic influence, like a number of books in the house, right, things like that. Yeah, yeah, yep.

And I decided so that led to this idea of the nature of nurture, which I'm sure we'll get onto. But the television viewing, which you bring up now, I decided to do because after several years I started realizing, I think that measures of the environment usually show some genetic influence, and that's kind of a profound thing. In a way. You know, it suggests that the environment isn't out there happening to us. We make our environments, so

I use this television viewing thing. By then I was a professor, and the nice thing about tenure is you don't have to care so much you know about what people think. And really, some people said it was like a suicide note, writing a paper saying television viewing is genetically influenced because it's used in thousands someone told me five thousand studies as an environmental measure. You know, it's

a big deal back in the seventies and eighties. And you know, I even had I was even surprised by it because you know, you think parents control whether the kids watch television or not, but they don't really, and some kids want to watch television more than others. And I think, as the case of all environmental measures we use in psychology, it's not the environment and out there. People create their environments. So kids can turn television on

or off, you know it will. So I think it makes a profound point about the genetic how genotypes become phenotypes. It isn't that DNA just can sit on the table here and create an organism. It has to work in an environment, and kids create and select and modify their environments in a way that's correlated with their genetic inclination.

I mean, that's interesting. Do you think that some kids were more inclined to watch mister Rogers versus you know, we talked about individual differences and content of television viewing. When you get to that level, I mean, I really strongly want to believe that mister Rogers really influenced me profoundly as a child, that if I didn't have mister Rogers in my life, I would maybe have turned out different. But are you maybe suggesting that my actual active genotype

sought out and was attracted by the messages he was providing. Yep. Well, we had this ten minute interview to measure the kids television viewing, as you know, any of these things to measure it, right, you know, someone say, oh, all I got to do is use this one hour interview. Well, we couldn't spend all that time when we went to the homes of these hundreds of families year after year.

So we had a ten minute interview and all we could really measure reliably was the quantity overall quantity of viewing. But as I mentioned in the book, we also took a look at some other things, you know, like broad categories of content like comedy or action or educational programs, you know that sort of thing. And I was amused to find that, mostly because I don't get comedy very well. I mean, I don't find many comedy programs funny, especially you know the TV serial sorts of comedy. Well that

I'm honored you left at my joke. Then that makes it even more special that you left. Mister Rogers. I agree with you. You You know, what would we do without mister what we do without him? I mean it's like, you know, there's no mister Rogers, Gene. This is so sad, Scott, you know, yeah, why is it sad? People are going to say God does boffins as they call them here in England. You know, boften sort of like a scientist

in an ivory tower who can't button his shirt. You know, I've never heard that expression before often that maybe that's good, Maybe that means I've referred to here in England. Okay, but it you know, well, anyway, I did that television viewing study. It shows genetic influence on not only quantity of viewing, but one of the more heritable categories of

viewing was comedy. There's strong genetic influence on how much you enjoy comedy and comedy television programs in the nineteen seventies and eighties, which is probably quite a different thing from nowadays. Yeah, I mean, that's an interesting question, and that, I mean, that's a whole separate pair question. How has comedy changed over the years? Really to go there, So let's really get into some of the biggest findings in psychology in your lifetime, you know, relating to this that

your life's work. So falling naturally from what you just said, almost everything is heritable, every psychological trait. Could I catch you up there? I know where you're going with this, But I think that first law of behavior genetics, that everything is heritable, and not just significantly but substantially, is such an important point because in my career back in the seventies, convincing anybody that anything is heritable was a very difficult task. It's good to kind of step back

and say, there's been a massive change. I mean to the point where I've even been telling people I wonder if you agree with this. I think we ought to challenge anybody to come up with any trait that's reliably measured and sufficiently powered in a behavioral genetics study that

shows no genetic influence. You know, actually I did a broad literature search to answer that question when I was working on my book un Gifted, And I'm literally googling my book right now because I don't remember what the two I found were, but you might be interested to see what they are. Okay, I'm literally googling my book right now. Hold on, I'm going to find this, yeah, because I found it fascinating that. Okay, the most important lesson I'm just literally reading a paragraph of my book.

Hope you don't mind. The most important lesson researchers I've learned over twenty five years worth of twin studies is that virtually every psychological trait you can measure, including IQ personality, artistic ability, mathematical ability, musical ability, writing, humor styles. There you go, creative dancing, sports, happiness, persistence, marital status, television viewing, female orgasm rates, aggression, empathy, altruism, leadership, risk taking, novelty seeking,

political preferences, television viewing. Did I oh, I repeated television viewing. My editor never picked up on that. Oh well sorry, And even rates of Australian teens talking on their cell phones has a heritable basis. Because our psychological characteristics reflect the physical structures of our brains, and because our genes contribute to those physical structures. Is unlikely that there are

any psychotocharacteristics that are completely unaffected by our DNA. And then I have a footnote where I do is something that I found, although a few traits such as love styles and materialism don't appear to have a heritable basis. Okay, so tho's the only I did find those two things? Yea, yeah, I know a little bit about that romantic love style thing, and I think there have been subsequent studies showing oh really, well this was published in twenty thirteen, so it's entirely possible.

But what was the other one? Scott? Materialism? Interestingly enough, I find that hard to believe because interests all show genetic influence, don't I know? Yeah, I mean you're right, locational interests certainly do, but you know, the extent to which you value money, it seems to have a much greater environmental influence. I could try to track down that paper,

but I don't know. But you know, for my dissertation in nineteen seventy four, in a twin study, a family twins study of personality development, I thought, what's troubling me is that everything seems to be moderately heritable. And this temperament thing I was working on with Arnold Buss was trying to say which aspects of personality are more ritable than others, and we came up. We wrote two books on this, the Easy Theory EASi emotionality, activity, sociability, shyness,

and impulsivity, picking these as the most heritable traits. And they also seem to be evolutionarily important in that you see them in all primates and most mammals. You know, these traits emotionality. But then in the end, I think we've got to say there's no evidence that they're any more heritable than any other traits. Right, So for my dissertation, I did a survey of psychologists saying what traits do

you think will show no heritability? And the ones that I put into my dissertation were things that I thought as well would not show heritable influence, like how about table manners? You know this isn't kids now and that's probably correlated with agreeableness. Well that's the thing, but you

know that now. But back then, you know, I think it was a reasonable to think, well, these are the things that psychologists think couldn't possibly show because you know, table matters kids either their parents either insist on it or they don't. Brushing your teeth after meals, you know. So I put in those things and you know they came out just as heritable as everything else. Yeah, okay, so this one was interesting. I didn't know this when

I was reading your book. Did you say weather is heritable? Yeah? You got to explain that to our listeners. You know. I think when people get into this nature of nurture idea, the idea that what in psychology we call the environment isn't the environment out there? You know, like life events? Does shit just happened to you? Does divorce just happen to you? As if you don't have anything to do with it? You think about it for many to think, no way, and that's where the genetics comes in. You

do have something to do with your environments. So I use this just to provi pative thing. When you start thinking about this, what environmental thing that we measure in psychology could not possibly show genetic influence. So then it's sort of a joke, you know about Mark Twain and people always talk about the weather, but you can't do anything about it. Nobody does anything about it, you know, and the thing and so then I said, is that true?

If you had seasonal defective disorder, you might choose not to live in England, you know. And so people can choose it that way. But a more profound aspect of it that I talk about in the book is relevant to me. I'm such a you know, disgustingly optimistic person. I drive people kind of mad because you know, I always see positive aspects of things, and even the weather in England. You know, you asked me about last summer's weather and I remember sailing and swimming and you know,

walks in the sun. And other people said, are you out of your mind? It was the worst summer on record, you know. But what matters to me in a way is my perception. That's my experience of it, even if it's totally off base, that's what affects me. I think. So that I think is the most more profound aspect of the weather. It's how you perceive it. And yeah, that's a profound point right there, because that doesn't we can build up from weather or build down. I guess

built down from weather. That's right, because you know there's like resiliency, you know, post traumatic growth. Who are those that have experienced post traumatic stress versus post traumatic growth from trauma? I mean, this is a very important question in the field of positive ecology, right, yeah, and other fields. So no, And that's a great example because you know, the trauma that you're talking about, this is horrendous stuff.

But for you know, a lot of people, you can understand if someone's devastated by it and now life falls apart, But any any experience like that, some people will be more resilient to it. To the point where you're saying that it's actually what did you call it growth? Post traumatic growth? Yeah, the field on that, Yeah, not a whole field on that. But I was going to mention this later in the conversation, but it seems relevant now. I've been fascinated with research on the effects of extreme

trauma on the brain. You don't go too much in your book on kind of extremes of environmental adversity, but I've been very interested to looking at some of that recent research on emotional abuse or severe sexual abuse in childhood, and it really does alter connections long term in the brain and how we process reward, how we process, you know, whether or not we are more avoidant in our lives

versus approach oriented. But in that research, I found this subset of research within that field showing that surprisingly some brains has showed those connections, but those individuals are still thriving in life despite those altered brain connections, whereas some other individuals show the same exact brain alterations from these

experiences but are suffered more from depression and anxiety. And I think that is absolutely fascinating line of research is understanding sort of what are the explanations for this despite you're taking people the same exact effect neurologically, you know, in the traumatic experience, and some people team seem to

have maybe some protective factors of some sort to interact. Yeah, and that's probably a good point, just to interject something that in all the media that comes about from my book, I realize it's so important to say you mentioned it that I don't talk much about extreme environmental events or extreme genetic events like mutations for exacts, A good points somal anomalies, and what we're studying is the normal range of variation in the particular samples that we can study.

And that's not trivial. I mean, it's the world we live in. But we're describing the genetic and environmental causes of the differences we see in this normal bell shaped curve, and that those descriptive statistics can change in a different culture. It's kind of surprising how similar the results tend to be across different cultures, but they're not maximally different cultures, and they as the normal range as well. So when you go outside to trauma or abuse, you know, all

bets are off. I mean, you can have a highly heritable trait and you can totally screw it up with a severe environment. But I also like to say you could totally screw it up with some weird genetic effect too. I mean, you feed kids mutangens and you can have weird effects as well. So I don't want to trivialize those extremes because for the people affected by single gene

disorders or by severe environmental trauma, these are tremendous effects tremendous. Yeah, they don't explain a lot of variation in the population. I'm truly glad that you made that point because I read a terrible review your book recently in Nature. I don't know if you saw that one. Oh yeah, it

was so bad. It was good. And I think that what people sometimes mean do is project And I think I see this sometimes in the media, like project onto scientists, Well they must believe X, y Z because they said A or B. And so I'm glad that you are on the record making that point because I think that

is a really important point. I mean, there were things that I read in some like that review and some other reviews where I'm like, well, I don't think Robert would actually say that to me, you know, like if we actually had a conversation. So I'm glad that actually happened where you made that point. So that was good that you made that point. And I think that, like it makes sense from an evolutionary point of view, Like,

tell me what you think of this. I mean, we have the genes we evolved to process a certain range of environments. But when we have such extreme conditions that are totally like uninterpretable to the genes so to speak. You know, that's a metaphor. It's not obviously like they're cognitively processing it. You know that it would make sense it would throw out of whack or from an entropy perspective, it would increase entropy dramatically, right, Yeah, I really agree?

Yeah yeah, cool, Okay, So let's go into these biggest findings in psychology. So another one. In the first one, we did the nature of We sure did so we before to go, we affore to go. Right, So development, let's talk about development heal heritability cases first. I'd like to say, of those five, it's interesting to me that two of them are very much about the environment, the nature of nurture and this the last one, the non

shared environment sort of thing. And we only have those findings because we have genetic designs that consider environment in a genetically sensitive sort of design, and the decades of work that ignore genetics couldn't do that because they're completely confounding genetics and environment. The other thing I'd like to say about that is that these two environmental findings are the ones that kind of lead me to the implications that I talk about in the subsequent chapters. We'll kind

of put those together. After we describe these findings so about development, The bottom line there is that for a lot of traits like personality, there isn't much evidence for changes in heritability. That is the extent to which inherited DNA differences are important in explaining the variance of a trade. There's a much evidence that herotability changes during the ability, but when it changes as it tends to, it goes up. I don't think there's an example of heartability going down.

And the reason that's important is that in psychology we need counterintuitive findings. If we're always finding things that confirm what your grandmother knew, you know, that's okay, that's science,

but it's not very interesting or exciting. Whereas if you can talk to a public audience and tell them what heritability means and ask do you think heritability goes up or down during development over your life, they'll say it goes down, and you ask why it's because, well, in the environment builds up you know, accidents, illnesses, slings and arrows of outrageous fortune, you know, those increasingly playing the differences between people. Part of that assumes that genetics is static.

You know, it happens at the moment of birth. So it's interesting to say that heritability increases, and the trait that is clearest is intelligence, where hairtability increases from like twenty percent in infancy to forty percent in childhood to sixty percent in adulthood, and some people say eighty percent in later life bar dementia, And those are huge percentages

of variance. You know, when we talk about heritability being about fifty percent, it's important to say, what else in psychologic we got explains five percent of the variance, you know, so fifty percent is a lot of the variance, and increasing the variance explained from twenty percent to sixty or eighty percent is off the scale of what we find in psychology. So this is a really big change in

these are the question, well, why could that happen? And I think the basic answer is nobody knows, but it seemed most people are kind of think that it has something to do with ge correlation. That is, it's sort of what I was saying before, that the environment, that genes don't just work by themselves, that genotypes become phenotype phenotypes through the use of the environment. So you know, musically, gifted kids you could almost it would almost be difficult

to stop them from developing their musical ability. Ellen Winter has referred to them as having a range to master. Yeah, and whether it's mastery or not, whether it's just engagement, you know, getting off on music. You know, they'll just sing to themselves, they'll bang on pots, they'll listen radio,

they'll hang out with friends who like music. So they're creating environments that are correlated with their genetic propensity, so that the genes nudge people in different directions, and then those differences snowball as you go through life, and so

those genetic nudges become bigger differences later on. So I've got this ninety seven year old father who lives in a residential place with you know, a lot of older people, and the differences are in cognitive related ability experiences are amazing. You know. There's some people who just sit the bottomized by TV. You know, I think a lot of older, sad, older people do. But there's others who are desperate to engage in arguments and conversations with people, and they're still

up on the news. And I think that's sort of the end of this snowballing process. I think so It's a very important concept. And intelligence is the best example of increasing heritability. Some people say it's there for weight and some people say for depression, but I think that's less well documented. Well, so I always tell me if I'm interpreting this incorrectly, I always view to that increasing heritability as I agree with you about the gene environment correlation.

Explain the effect. But you can't, like Parr's environment out of that equation. Like, it's not like we become who we are just naturally completely regardless of the environment and we experienced in our lifetime. It seems like from a within type, from a like to explain this as a developmental within person perspective, not large populations, you know, trying

to explain variants explain, but within a person. It seems like you can't simply remove you know, the opportunities that you've had in your life or that you know when

you seek out these opportunities. I mean, people have to actually allow those opportunities to happen, right, And yeah, yeah, there are others nine seventy seven paper Insight bullet, you know, John, with John Lowland and John de Freese, we sort of talk about this issue and it's a bit tricky because you know, as you're saying that genes by themselves can't do anything right, But it's this matter of genes kind of pushing you towards certain environments, you know, like where

I see it. I particularly interested in the business end of cognitive development in schools. You know, with children, it's an educational achievement. And you know, teachers will tell you, you know that they're teaching the kids this sort of curriculum, but some of them just eat it up, you know, and they're shooting up, and others really struggle, and you know, you have to put more energy into it. So yeah, they need that environment. You lock a kid in the

closet and they're not going to develop cognitively. But you know, it's even more basic than that. DNA by itself can't do anything. It needs to sell. It needs an organism, you know, for that self, and it needs an extra an environment outside the organism, and the genes work to have you use those environments, you know, to follow that propensity, and it is just a nudge. It's not deterministic, which is another thing I get in these comments from my book.

You know, we're not saying genes determined the behavior. It's just other things being equal on average in the populations. With these genes and these environments, we're finding genetics accounts for a huge amount of variance, but it's on average. So even with obesity, I mean, you know, could it surprises people to find it's maybe seventy percent heritable b M I. You know, body mass index maybe seventy percent heritable. But it's not the genes determining your body weight. It

could have been one hundred percent heritability. But if you just stop eating, you're going to lose weight. Yeah. Yeah, that's a really good point, you know. Or let's say you have a genetic propensity towards alcoholism, but you'll grow up in a culture where you never see alcohol your entire life. You know, it's not going to trigger that propensity, which I mean brings up a really fascinating point about how we can change our destiny. You know, where does the free will come in? I think a lot of

people are curious about that. It seems like one way is kind of tying yourself to the mass, or like limiting the experiences that won't tickle your genome in a bad way. I've never put it that way before. But it seems like that this is kind of the crux of the DNA revolution and how it's going to impact psychology,

society and ourselves, you know, our self understanding. And I've been upsetting people by saying, you know, all the concerns about the director consumer testing, and I'm sure we'll get into the DNA side soon, but just to skip ahead to that, I think because it's relevant to this particular point.

You know, we could say in behavioral genetics that if you're male and your father was alcoholic, you're at a what a fivefold greater risk of being alcoholic, But that's sort of a family wide risk for you and your brother and your sister. But with DNA, we can say you have a genetic risk, say tenfold, and your brother doesn't because siblings are fifty percent similar but fifty percent different genetically. And people say, oh god, you know, that's

so terrible to have your genetic future foretold. Well, alcoholism is a great example because, as you say, you just cannot become alcoholic unless you drink a lot of alcohol. And what worries me is our universities are sort of like experiments to find out if you have a genetic propensity for alcoholism because you're so overloaded with alcohol. So I think if you found out that you had a genetic risk, I would like the NHS, the National Health Service in the UK. It is one of the great

things about the UK. They already do genetic testing. You know, all countries around the world do neonatal genetic testing for PKU and things like that. For the same amount of money, they could get these snip chips and do this genetic sort of testing that I'm talking about. And then if you found that, you say, had a tenfold greater risk of becoming alcoholic, wouldn't it be almost unethical not to

tell you. They're not going to say, you know, we're going to be totalitarian and take away alcoholic, just going to say, I thought you'd like to know that if you drink as much as other people, they're not going to become alcoholic, but you could you have a much greater risk of becoming alcoholic. And you can judge that information and say, yeah, is it worth it? You know, maybe I need to monitor my alcohol, Maybe I need

to take these month long breaks from alcohol. You know, I'm going to be cheeky for a second, but I mean, is this going to interact with other trades? It's like, what if you also have a hyperpensity for OCD or neuroticism. Wouldn't that make you like you live a life for your constant or where you look You're like, oh, no, that might wead alcoholism because I have a high probability I'm saying. Do you see what I'm saying, Like, wouldn't that interact with each other where you become like obsessed

with this your whole life. But it's a good point that people aren't schizophrenic or alcoholic. They are people and they have various problems, as we all do. And so you know, I take your point, but I do think alcoholism is such a severe problem that it's probably okay to kind of focus on that and say, yeah, you're an individual and you know maybe if you're OCD or whatever and I tell you have a risk for alcoholism, you're going to freak out. Yeah, But you know, is

that so bad? I mean, you know, right, but there could be other things. Yeah, but you could see Yeah, but you could see like other examples where it would be pretty bad. Like I mean, intelligence, Well, intelligence is a really interesting one because we actually know more about the genetics and influence low intelligence. We don't really know very much about genetics that influence like extraordinary high IQ.

So that's interesting, Right, what would you to foretell in that situation that you have a genetic predilection to have a low IQ? And then what would that knowledge? How can that help you in life? Yeah? Well, intelligence is the toughest one, but I'll get it. I went right there,

didn't I? Yeah, but you know that's good, And you know I have done studies, very large samples looking at low versus high intelligence, and in general you find that all of these what we call disorders are really part of the quantitative distribution, which we're going to get to. That's this finding on the abnormal is normal. But I think where you were going with this is to say, what if you find out you have a kid who

has a genetic prediction of lower IQ? Yeah, like their a polygenic genic score, like because we're talking like about thousands of genes, right, but yeah, that's we're not saying like one gene, but we're saying that like all those genes together kind of we know that in the general population that's correlated with well IQ, Like do you think

that is valuable information for anyone at that age. Yeah, if you find you have university parents, this is the toughest one you know to face when your kid isn't doing well at school. And I actually think we can take that on with pologenic scores. I think one of the biggest impacts going to be for people to realize how different siblings are. So parents who are university educated, they find one kid isn't doing well at school and the other kid is. This is like me and my sister.

My sister was slowly learned to reach that didn't do well at school. She didn't like school. It was hard for her. I love school. I couldn't wait to go to school, you know, and I love to read, and you know, as a parent, you can't. My parents didn't go to university, so it wasn't the problem of university educated parents can't bear the thought of their kid not going to I suspect I haven't done this, but if I tested my sister, I bet she doesn't have a

very high polygenic score for intelligence or educational achievement. And my parents didn't worry about that. I mean, no one in my family went to university, so the weird one was me going to university, not the rest of them not going to university. So I think it would be good for parents to know how different kids are. And if you found that one of your kids didn't have such a high score for educational achievement. It's sort of tough to take in one way because we're so we

value intelligence so much in our society. We do and we don't. We do and we don't right like we maybe say we do, but we actually don't want to talk about it. Right Well, that's true, and there's all this stuff about we've had enough experts is you know, and a populism in a way might go against intelligence. But the point I wanted to make is that maybe it would be good for parents to know that one

kid maybe isn't academically oriented. And it's the goal that all kids you go to university, maybe it's better to recognize some kids aren't really cut out for it, and they probably don't like it either, you know. It's this

kind of circle of appetites and aptitudes. And I was doing a thing with CNN in Switzerland earlier today, and they're very keen on their vocational training with apprenticeships where people get into really good jobs, you know, highly paid, stable jobs that are very enjoyable because they value these jobs. And do we only about in the England it's territ You either go into academic university tracks or you go

into what they call O levels occupational levels. But that's like, you know, play with your pencils until you get to be sixteen. There's no training, there's no apprenticeship program, there's no job at the end of it other than you know,

flipping hamburgers. So when you said some people are not cut out for, I think that's an interesting statement and it actually, I want to be honest, it raises my blood pressure when you said it, so I'm trying to really suppress my emotion when you said that, so I can really think about that as analytically as possible, because I feel like, should the genes tell us that information though, whether we're cut out for, or should the person the

human tell us that once they've given had the opportunities and tell us how interested or motivated they are to do it. So absolutely, yeah. But what I'm saying you're upset about because you think it somehow has been deterministic, and I'm not saying that at all. You could make your kid, you know, force them to work hard at school, give them extra tutoring and all of that. But might it not be better to go back to what you were saying before about going with the grank, you know,

going with the flow rather than swimming upstream. Just to say, maybe it's the cutout that bothers you, but maybe you know, as a parent, you want to do what's best for your kids. You want to maximize their strengths and minimize their weaknesses. You don't want to preordain what they ought to do, like go to university. So I agree with that, But I think another part of this is selection, and you know that's where a lot of this comes in, that we select kids for the better schools and university.

And I agree completely with you. I would rather get rid of selection, and so like open university here in England. Let everybody go to university. Don't just take the ones who did well in high school. You know, that's a pretty good predictor of how you're going to do it university. But there's a lot of kids, you know, grew up in high school, but then they get their act together and they really want to go to university. Let them go to university and see how they do it university,

sort of like adaptive testing in a way. I do think that, Yeah, actually giving the people the opportunity before, not making decisions before. We do that. So analytically, the analytical argument here would have is that we only know that. Like, in terms of individual prediction, the highest essment I've seen is that polygenic scorers only explain fourteen percent of differences in IQ and maybe a little bit higher for educational attainment.

Why not just stick with the phenotype. Why not stick with like their tests that are better predictors than polygenic scores. I published this paper in Intelligence with some of the leading IQ test constructors, finding that the correlation between the chief general intelligence factor and the academic achievement factor was like above point seven four starting at age two. So we looked at developmentally age two to seven, and the

correlation did seem to increase, There was a trend. It actually went up to as high as point ninety four, the correlation being point I mean, that's talk about percent variants explain. That's extraordinarily high. It seems like that beats the pans off of apologenic score Yeah, but in fact, you can't predict from two year olds. You cannot predict what did you say, how much of the variants fifty percent of the variants of high school in the AH. We're talking about within so at the same age, so

two year olds the correlation between there. But if you're talking about educational achievement in two year olds, right, I mean that's a good point. But when you looked at it, I'll take you seventeen point. Because DNA can predict from birth. Nothing else can predict educational achievement from birth. Well, what about Fagan's research on showing its involved in that? You

know it doesn't predict anything? What people wrote a book chapter for my Cambridge Book of Intelligence where he he said that you can predict infinite tention measures about point three four with IQT seventeen. Yeah, not true. I think subsequent studies don't confirm that. I don't think you can predict anything, just like you can't really predict adult height from infant height. A birth weight, an infant weight doesn't

predict at all later weight, right. The only thing that predicts in an individual is DNA, and having that predictive power I think could be useful to identify kids who are likely to have problems and give them extra help, for example. But intelligence is the hardest one of all. If I talk about reading disability, no one has problems with any of these issues right right sure to dyslexia. Maybe it could be useful information to see if you

can't predict that from anything else. Kids don't. You can't test reading until they read, and by that time they have the reading problems. But what you can do is if you could predict who's going to have reading problems, they almost all have language problems earlier, and there are good intervention programs for language, like at two, three, four years of age before kids learned to read, So you could actually prevent reading problems by intervening with language interventions.

What I don't understand is because this fourteen percent number for I qu Yeah, it shows that this matters to some extent, But it shows there's just so much unexplained variation that the question of like, at age two, do we want to like make that decision that person's not cut out for it, you know, at age two, based on like so much unexplained variables that we don't know in that child's life. Yet I would argue that would be dangerous in fact to do. No, it's useful information.

And like the reading disability example I just gave you, it still is explaining a lot more variance than we can explain with other things. It's very predictive. And what you're saying is you could predict with childhood intelligence, you could make a better prediction of achievement. Well, you know with school achievement. Two years ago we could explain what two or three percent of the variants in educational achievement using educational attainment and adults in a genome wide association study.

And yet it's still would predict two or three percent of the variants. Then you know last year with that new g BOSS for Educational Attainment, we can explain ten percent of the variance. This year with the paper that just came out a couple months ago with one point one point one million people, well we can explain fifteen percent of the variance in these GCSE scores. It's impressing. Now you say, well, that's not that much, But in

England we have these amazing offseted ratings of schools. They're really twenty thousand pounds per assessment. They do it every three to five years of every school. They're the best sort of rating of a school quality you could do. I mean, you know they're not perfect, but nothing is. How much variance in GCS scores is accounted for by how good the school is? You want to and the answer is about two or three percent. So I certainly

agree it's scientifically impressive. And by the way, like kudos to the researchers who are making such strides in their discoveries. What I'm questioning is, you know, how do you get from like fourteen percent of the experience explained to like fortune telling? To me, that seems like such a leap that you made in your book. That doesn't seem warranted massing the evidence, but you think it is warranted. Yeah, absolutely.

What about alcoholism? You know that's not such a good predictor how much of the experience and liability of alcoholism can we predict? Now? What is the actually know, it's not much. I don't know what's six seven percent? But what else predicts alcoholism other than alcoholism in the parents? What in the individual would give you an individual prediction of alcoholism? Now it's all going to get a lot stronger, right, because heritability of the liability to alcoholism, what forty percent

or something like that, fifty percent? So these are going to get stronger. But even right now, wouldn't you want to know that you have an elevated risk for alcoholism. I'm thinking that through. I don't think the answer is obviously yes. So that's why I'm thinking this through, because of the extent to which there's so much error in that estimate. Yeah, but Scott, we never have strong predictors. How about this drinking. How much of the variance in

automobile accidents is accounted for by blood alcohol levels? So I imagine it's pretty high. No, I don't think so. I think it's quite low. There's a lot of reasons why people have accidents, and actually I did work on blood alcohol level. It's not that predictive of performance. It is true that people who are drunk out of their minds are more likely to have an accent, but there's actually a lot of people who can drunk, drive very

drunk and not get an accidents. So all I'm saying is we make laws, very severe laws about drink driving, and I agree with them, but I don't think blood alcohol levels correlates that much with total accidents. And I think a lot of things, like what about smoking two packs of cigarettes a day and lung cancer, one of the stronger relationship doesn't explain a lot of variants. You know people who smoke two packs a day and don't have lung cancer, and you know people who don't smoke

much at all that do get lung cancer. None of our predictions are ever perfect, but those are ones that we make massive decisions about, almost legal decisions in the case of drunk driving. So I think it's unrealistic to expect that we're going to explore all of the heritability, even and we know we're not going to explain all the variants because these things are only fifty percent heritable

to begin with. But I think it's very useful information, Like with reading disability, that's my main goal is to be able to predict early in order to prevent problems. Yeah, and I think it is an interesting question to what degree can then information inform a useful intervention, because I would hate to see it used strictly as a sorting mechanism. Now, if there's some purpose to it, like some sort of to help the child, then I can start to see

a greater humanitarian purpose. But when it becomes strictly as like we're going to read the genetic information of tials and then use that information to sort those who are not cut out versus those who are cut out and give all the reasons. So now you're miss reading it. You know, you know my book, I very much say that's not the purpose. I don't want selection. I want to avoid selection. But if you are going to select,

you ought to do it well. But I much would prefer or that we don't have any selection at all. The example that I would give that you're raising is I find university educated parents have a great deal of difficulty excepting that one of their children is not doing well at school. If they knew that kid had a lower genetic propensity, that doesn't mean they give up on the kid. It just means they have to decide how much extra effort do they want to put into that,

and they can do it. It's not deterministic. You can make up for that difference, but to what extent You don't want to preordain that all your children have to go to university or their life is wasted. If a kid's going to struggle with it, like my sister. Instead of blaming her or blaming my parents, isn't it better to say it's just a lot harder for her. I didn't deserve credit for doing so well at school. She doesn't deserve blame for doing poorly at school. You know.

So I think greater recognition and respect for genetically driven individual differences is important, and that polygenic scores can help us see that. Yeah, I'm listening to your perspective, and I'm taking it very seriously and trying to think through all the implications of it. You know, it's very interesting to think that we were all multidimensional right there, Like

success is a multi factoral determination. So you know, when I look at the genetic output of someone on the young intelligence was one dimension out of many psychological dimensions. Other dimensions could be like test anxiety, And it's an interesting question the extent to which well is that person's test anxiety actually going to suppress their expression of their intelligence. I've tried to spend my whole career objectively as possible looking at this research, but I do still know that

you know what happened to me. You know, I wasn't placed in You probably don't know my story but I was placed in special education as a child because of my intense anxiety that I had, just like generalized anxiety. I was anxious about everything as well as an auditory processing disability, and people treated me as I was stupid as a result of that, and that expectation, you know,

over the years sculpted who I became. So I do wonder in terms of the implications of this, this research you're talking about, how much are we setting up a self fulfilling prophecy by having people have certain expectations. Yeah? Yeah, And as I say, intelligence is the hardest one of all. But what if you know, we said alcoholism, no problem? What about even you know, depression, If you knew you had a genetic propensity and depression, doesn't that help in

terms of self understanding? I mean, as a parent, I would find it kind of useful information. It's not very predictive now, but you know, it's sort of useful information. It's not going to determine people's outcomes, but it's part of self understanding, understanding your kids, And in some ways I think it could be useful in education. As I said, for reading disability, no problem. What about ADHD? I think

something you know, that's going along pretty strong. They're coming up with what I mean, the next goal of the PGC, the Psychiatric Genomics Consortium, is something like eighty thousand cases of ADHD. And what's going to blow it open is when we get a polygenetic score. You know, that shows your genetic risks. And if you find for example, it's

sort of like a treatment by genetic interaction. If you found that, you know, in the States, we're going through this battle now in the UK where people don't want to go the US way where any kid diagnosed with ADHD gets amphetamines, you know, methyl fenidate. But what if you found that kids at high genetic risk really do respond well to methylfenidate. But maybe kids who are diagnosed as ADHD and don't have a high polygenic score, maybe

they don't. Or even more that, you know, you can get a polygenic score that can predict which kids will respond to methyl fenidate, which one or even more kids that will suffer from being on stimulants like methyl fenidate.

So I know there's a lot of doom bongers about the DNA revolution, but I do think, as I say in the book, the Genie's out of the bottle and you're not going to stuff it back in anyway, So we might as well have these conversations to talk about, well, you know, what limits do we want to impose on it?

And you know, some people are saying, well, regulate the whole thing, don't allow direct to consumer testing, and you know, I just feel it's a bit paternalistic in this day of you know, the web and free information to tell people you can't have access to your DNA data if you want it. What's happening now is parents doing it for their kids. Then you can say, well, the kids can't provide informed consent and that sort of thing. So there's a lot of issues that come up around this,

and I certainly don't have the answers. I'm not an ethicist and neither Yeah, and I agree with your book. I agree with you you state and now is the time to launch a broader public conversation about the applications and implications. That's precisely what I'm doing in this conversation. I wrote the book. Yeah, yeah, Yeah, I'm glad you did. I'm glad you're opening. We're going to get better and better polygenic scores and the pace of discovery is quickening, absolutely,

So let's move on from intelligence, if that's okay with you. Yeah, sure, I got out what I wanted to say, and I not too upset about it. Oh yeah, look I shouldn't. I shouldn't use what was actually made an analytical case though, you know that, like the we're so far from actually at this point in explaining individual prediction. It's getting pretty impressive in terms of group level prediction, but the individual prediction of that we actually the phenotypical test seem to

be right now, better predictors. Yeah, but you know, I showed the book that even the last year's polygenic score that we used to predict we call them GCS levels. These are school Leaving of National Exams at the age of sixteen. We call those GCSE scores. We're all explaining ten percent of the variants. But if you take the kids in the top and bottom desk styles, you know that you're talking about what eighty percent of the ones in the top deescile going to university and twenty five

percent of those in the bottom desktop. Now, you could say, well, that's a group thing, well, but it's not. That's just the reflection of a correlation of about point four that explains sixteen percent of the variance. You know, that's a point four is a correlation of moderate to large effects size in psychology. But you can say, yeah, but you know, there's a lot of variation from that regression line that predicts.

You know, GCS Scurse show in the book that with that sort of data, even though the mean difference is for these death styles, if you divide the polygenic scores into tens, the top and bottom desktop differ a whole lot. Nonetheless, you can find a few kids in the lowest dust style who do better on tests than kids in the highest deatht style. So it's not at all a perfect prediction.

I'm more concerned about how this could be applied. Maybe you're more optimistic than me optimist, Yeah, maybe what's going on? Maybe you're more optimistic that Oh we'll just you know, people will just use this in a way that is not going to turn into like, I mean, you don't mention the history of eugen X. You don't. You don't mention that in your book. And I could understand, on the one hand, why not to mention in your book

because it's not relevant to the science you've conducted. However, based on that history, like it shows what humans are capable of, right, And my point is, you know I could see this unless we really have an open eyest conversation about what is the point of this information. So I mean, I've been working in the field of educational psychology, and you know, the field of gift education is moving away from just using IQ scores as a predictor of

giftness because it's not actually informing any intervention. It's just operating as a way of taking those who are above a certain range and put them all in a room together and give them enhanced resources. I could actually be more on board if we if you said something like, you know, the dyslexia one's a great example, but you know, maybe some of the group factors of intelligence. But general intelligence is a tricky one because what if we say, to like a parent, you know, your child has a

real probability here of not doing well in school. Then that does that mean that if the child is not doing well in school, we say the causal reason was because they are dumb or they are low intelligence. No, wouldn't, But wouldn't it be good to be able to predict I like the Finish model, for example, where you know

you take kids. You just say we're going to put whatever resources are needed to bring kids up from the lowest to some minimal level of literacy and numeracy that you need to kind of to participate in our current technological sort of society. So I don't think any necessary there's no necessary policy implications from any of these data. I hear you, and I think that the research that you present you've conducted is quite pressive in the extent

to which genetics matters. I do think you underestimate the extent to which environment matters. So I've been looking at some recent meta analyses I'd like to discuss with you. I think they paint a more nuanced picture about the role of the environment, and I just want to get

your opinion on them. Sure, So I saw this Holderman at All meta analysis, which was one of the most impressive menalysis I've ever seen, where they looked at virtually every single isn't incredible, every single published and they have this whole visualization you can like play with it. I've been playing with it online than the nerd. I wait, what was the word to use before the in England? Of the nerdy person that I am yeah, the buffin

that I am yeah. And on the one hand, like that conclusion from that paper, it is certainly that you're right that the shared environment effects are small, but there were effects. I mean, I see point one three for temperament and personality, So you know, to say that like there's no effect there at all, I think is not quite correct. Well, I do think it is correct, though, I mean for personality of psychopathology, I don't see any evidence for shared environmental influence if you look at the

twin studies. I don't know why the meta analysis shows that, but you look at these studies, I think one thing you find is there's a special twin effect. So that's kind of well documented, isn't it that if you grow up with someone exactly the same age at exactly the same time, there's maybe a little bit more similarity than there would be in the population as a whole. I'm not against it, but I don't really see it. I don't except that there is evidence for shared environmental influence

for personality. I mean Chimer's review, for example, in the Annual Review of Psychology, he doesn't find any does any But this was like the largest MEN analysis on the time. Yeah, but it's you know, it's not very satisfactory in terms of what it includes, right, I mean it includes all sorts of measures. I mean, I believe in men analysis then includes like everything you ever studied than a smaller sample, right, Yeah, But it's not using the better studies, is it. For example?

I mean, all the large studies I know are quite even for twin studies, consistently no evidence for genetic influence. So I haven't gone into that because you know, it's looked over tiny studies, big studies. I know, meta analysis has some advantages, but it also is gross, you know, and you look at the bigger studies that have been done, and they consistently show no evidence for shared environment except

maybe for delinquency or anti social behavior. There's a little evidence there, but then there's counter evidence saying it's really being partners in crime in in adolescence, you know. So I just I don't see it. Yeah, I mean I don't really have a card in this race. I just want to discuss these findings because I think they paint a more nuanced picture. And what I'm going to do, by the way, is on the show notes. I'm going to put all these studies so the listeners can read

them if they want. So, I was fascinated by this Augustine Kong at All paper on what they refer to as the nature of nurture. How are you familiar with that paper? Yeah, I reviewed it. I had it rejected from Science I think when I reviewed it. So you don't think it as a high quality paper, Well, yeah, I don't think it's explaining much variance, and I really disliked about it. Pretend that it called it nature of nurture and never noted that there's been twenty years of

research on the nature of nurture. By the way, for the listener, I should actually explain what they found. So they showed that non transmitted illegles can impact a child through their effects on the parents and other relatives. So there is an effect of the parental genotype that is not transmitted. So that does suggest there is this kind of role of the parents matter, maybe more than you

present it in your book. But you're saying, well that there's ge correlation, right, yeah, And do they reference this? I mean, you know, it's like they pretend as if this research hasn't existed. For a long time. It's kind of a cute little measure, and it might lead somewhere. I don't think it's explaining much variance, but let's see what happens there. But to pretend that this has suddenly discovered the nature of nurture kind of irritates me because

we've been saying this for thirty years. So I think the interesting question is what is the implication of that finding? And you know, Collinger and Harden wrote an interesting comment ury on that paper, arguing that we can use that understanding they nature to understand how parenting matters for children's education. I can kind of get us better at the mechanism.

And they have this quote from this commentary. They say, for humans living in wealthy societies, genetic nurture might be more relevant for behavior and social achievements than for more biologically proximal outcomes such as body science. Do you disagree with that? Well, you know, that's if it even pans out. I don't think it's explaining much variance. You know, I remain skeptical, But you know, if it shows that it's a true effect, fine, but it's of no power compared

to an adoption design. Well, we can relate biological parents with their kids, and we find evidence for a lot of GE correlation. And with these designs like parents of twin design, you can separate out passive and reactive and active types of gene environment correlation. So you know, I think people are interested in this non transmitted leal thing because it's new and it involves DNA. I don't know that fundamentally it's going to tell us very much that

we don't know, and it's not very powerful. I would have predicted that you would say that, you know. I mean, they even say straight up in their commentary. The phenomenon of genetic nurture underscores that the results of genetic association studies cannot be interpreted as support for a biological determinist account of human individal differences, as most social scientists who work with genetic data have stressed. Helped this data suggest

just how tightly genetic and environmental mechanisms are entangled. We've been talking about GE correlation. DNA doesn't do anything by itself. For me, the bottom line is, if you take inherited DNA differences and you relate that the behavior, I'm going to call that causal I'm not saying I've explained the mechanisms, but I can tell you there's no backward causation as there is in most correlations in psychology, where X could cause Y, or why could cause that? The behavior, the brain,

the environment is not changing your inherited DNA sequence. Yeah, and I'm certainly not disagreeing that genetics matter. What I'm trying to do is show you some papers that paint a greater nuance of the effect of the greater nuance. But you don't think, well, I mean, why is that nuanced. I mean, We've talked about ge correlation for a long time, and I'm saying, let's not have nuanced, Let's have power.

Let's explain behavior and what explains behavior. Explaining behavior individual differences in behavior from inherited DNA sequences knowing nothing else to me is very powerful. And then it allows us to study the nuances of ge correlation, you know, and interaction and development with finally having a handle on the

genetic side. Instead of saying, oh, it's all nuanced and complex and can you know, people use that as an argument to say, oh, you know, we just can't really explain these things, you know, at a mechanistic level, because it's all through complicated. I will holdly state that I think that some of these studies I'm going to I have a couple more. I do think present a more nuanced picture than you do in your book. So this one,

can you use another word than nuance? Okay? Sure? Can I use a word that is not offensive to your program but adds additional data? Perhaps? Or actually I would say Connor Dix and let me see Conor di let me tell you about this study. Brand again at all variation in the heritability of educational attainment, and this is

an international meta analysis. We find that heritability shared environment and unshared environment each explain a substantial percentage of the variance in attainment across all countries, and that the heritability varied by nation for educational achievement, there is not even in our studies, you know, we find about twenty percent

shared environment for educational achievement. It's interesting. We did the first study of going into university, whether you go to university or not, that shows forty percent shared environmental influence. But performance in university, your score is at your grades

at university show very little shared environmental influence. And what I think this is about is Yes, there is some shared environmental influence on educational teament, much much smaller than the genetic No, that's not what they found though they set for educational teament. Not only is our grand mean estimate of common environment of similar magnitude to our grand mean estimate of herritability, but in thirty two percent of the studies in our sample, the estimated effect of common

environment actually exceeds that of genetic differences. Yeah. Well, we've done the biggest study by far, and we don't find that. I mean, find this one of the meta analysis. Yeah, you say that, but there aren't many studies really on educational achievement that have sufficient power to look at these things. So I'm just skeptical. And the thing to keep an eye on is intelligence. You accept the finding that their shared environmental influence in childhood but not in later life.

I do accept the conclusion that the heritability of intelligence increases as we age. Yes, But you accept the conclusion as well that shared environmental influences are important for intelligence in childhood, but they drop out to negligible levels in adulthood. That does seem to be what the data suggests. Yes, And then with educational achievement. You can only study that in childhood and then university. But there's very few studies

in university. I think ours is one of the only ones, and I think we're going to find the same sort of thing. I agree that there's some shared environmental influence. I don't agree that it's as much as you're saying that it's as big as intelligence. I know you completely accept the results of a meta analysis. Well, what I think is interesting about this paper is it also as an international and they so it found that heart ability varied significantly by nation. To me, that does suggest that

if we look take a broader view of cultural differences. No, I think that's fine, And there is some evidence that shared environmental influence is greater in the United States, and you know, there's papers suggesting that the reason for that is the decentralized education system, where education is allowed to maximumly differ across communities, whereas in England, to some extent, Australia and some European countries there are these national curricula.

It's probably greatest in the UK, and so if you really have a universal education, it will cut down on environmental variation, which means genetic variation heritability will account for more of the variation that you see. Yeah, I think that's a good point. And so that's a good point. And you're talk in your book about how we can use heretabilitical efficients as a way of actually judging the fairness and equity of environments and opportunities, and I am

on board with that point. Yeah. So I agree that you can find different results in different countries, and you know, your results have to be limited the country you're studying, and meta analyzes are kind of good on that score. And it's an interesting possibility that shared environments greater in the States than it is in other countries if you look at the power, though I don't think they can

show that it's significantly different, you know. I think relating to that is the Tucker draw, the Timothy Bates Tucker job paper large cross national differences in gene by socio economic status interaction on intelligence finding that you know, in this large Deale study and studies from Western Europe and Australia where social policies and shore more uniform access to high quality education and healthcare, gene by sees effects were

zero or reversed. Yeah, what do you make of that? Well, I think when the first study was done by Turkkheimer, it had absolutely no power to detect the gene environment interaction, right, you know, the original twenty thirteen. But this paper seems to be much better. But then the only studies that are showing this effect are Tucker Drob or his students in the US. Most of those studies are incredibly underpowered

to detect the gene environment interaction. I've done a paper where I show that you need about two thousand pairs of twins to get any sort of reasonable power. Those studies don't begin to approach that. So I am skeptical about it, and certainly fine with one of the largest studies no evidence was what we actually find an effect in the opposite direction, slightly but not significantly. So it

isn't really a meta analysis of the world. It's a few studies in the States from even one of the bigger studies in the States, what is it, the Vietnam study or one of those studies don't show the effect. So I'm still a bit skeptical, and it's something you call it nuanced. You know, people want to find gene environment interaction and I'm not against it. It's just I don't see much evidence for it in that specific topic.

But more generally, you know, all the candidate gene by environment interaction studies, you know, journals now aren't even accepting those unless you show replication because it's sort of like a poster child for failures to replicate, you know. So I'm skeptical or ge interaction, and I'm puzzled why people are so keen on it, whereas though I think, no, I don't see that, And what I think is important is gene environment correlation, and people don't get into that

as much. That's how genes work, I think so. Also, Stuart Ritchie and Tucker Drab did the huge medice analysis showing that education has a causal effect on IQ. Yeah, and they say education appears the most consistent, robust, and durable method yet to be identified for raising intelligence. Yes, and how much variance does that account for proximally one to five IQ points for every additional year of education and that has huge social implications or how much variance

is that? Stuart Richie is my colleague, you know I'm talking about this, and you know he agrees the effect is incredibly small in terms of the variants explained in the population because most places have compulsory schooling. You go to school for a certain number of years, right, So this is based on things where what you go to extra classes and you know, things that are outside the normal. And you know, all we're talking about is what exists

in the real world. Isn't much variability. I mean, the vast majority of countries around the world they go to school compulsorily to what sixteen or something like that. So I don't think it's accounting for much. Arents it could make a difference. That's the way I interpret it is to say, you know, if we had kids go to school more, maybe it could have a bigger effect. That's it could be. It's actually an interesting point because I've

been thinking about this from like a variation perspective. Well, you say in the book use language such as like it doesn't make a difference education, parenting doesn't make a difference in becoming who you are. But technically what you're saying is it doesn't make much of a difference in explaining differences in who you are. But that's like saying, like fish in water, if you take the water, they

don't vary at all in water. But if you take the water away, like the fish dye, so you know, your statement doesn't seem to be in who you are. That's a developmental question. You're misinterpreting. What I always say is parents' schools matter, but they don't make a difference. There a difference from individual differences point of view. Well, that's when I emphasize that I have a whole chapter saying we're only talking about individual differences. We're only talking

about the one percent of DNA that differs. We're only talking about things that make a difference. And I try to emphasize that's not the only perspective on things. You can talk about universals. Why is the human species a natural language user? Why do we walk on two feet? Why do we have frontal vision? Those universal questions are important, But I'm particularly interested in, as you are, individual differences. So I try to throw that in every now and then.

You know, it gets boring every time you say any trait to say individual differences in. But I hope I've made the case if someone reads the book that we're only talking about the sources of individual differences. You know, I was thinking, I'm going to give you a point of agreement, and I like to go back and forth between and let you know we're absolutely where I agree with you I thought, and where I think you had

a good point. You know, you talked about parenting is kind of like, you know, let's like observe like who our child is becoming, as opposed to trying to make them into something. One of my favorite psychologists, Abraham Maslow, you know, referred to he said, we should be horticulturists.

That's what parents and educators should be. And I always really like that metaphor, you know, as a horticulturist, right because you're kind of sculpting who the person is already, you know, potentiality, and we're kind of helping them kind of become that person. You know, Elic's book, you know last year, Oh yeah, gardeners and carpenters and saying parents aren't carpenters, they should be gardeners. But in my book, I e didn't say I'm not so sure they should

be gardeners either. It is by that you mean you're going to prune the plant and nurture it so that it grows to be a certain thing, you know, like this is an iris, it's supposed to be like this, but you know that's that's a bit of a subtlety. But I take what you're saying so interesting about the mattering. When you say they do matter, you say, well, they matter in the sense that the way we treat our

children really impacts who they become. If we treat them in a way that's more controlling or forced, we can actually be taking them away from their destiny in a sense, So they matter. No, No, I don't think that's it at all. It's more like you were saying water and fish. You know that they can't say water isn't important for fish because if you take it away, they die. Well, in some ways, parent things like that, we're mammals, infants

are born altricial. Parents matter in the sense that they provide the essential ingredients physically and psychologically for kids to develop. They will die without parents, you know, in the grossest way. But even more than that, you know, parents are a very important relationship for kids. Good, But do they make a difference? And I would say no, You know, it's there's two different levels of analysis here, which I think

it's tricky. There's the developmental level of analysis, and then there's you know, partitioning sources of variance, Like things don't have to co vary between people a lot in order to be important, right, I mean obviously you would agree with that. I don't know what you mean, Like the water example was a good one. When you calculate heritability estimates, we're talking about the factors that we're controlling for the factors that vary environmental factors. I try to say, we're

only talking about variants. We're talking about difference between people and what makes the difference. But that doesn't mean that the factors that don't show much variation, like having five fingers on my hand, you know, like most everyone has five fingers on their hand, but that actually obviously was biologically genetically determined, you know, even though it didn't have much variability. Like language use, and like frontal vision and bipedalism.

These are all basically universal characteristics, right right, So if we're not clear about that, it's really important to get clear that we're not talking about things that make us human, like the ninety nine percent of the DNA that's the same for all of us. We're talking about the things that make us different, like the one percent of DNA that differs between us. I'm not saying make a difference. I'm saying parents matter, But they don't make a difference.

They don't make you think they make a difference when it comes to things that we don't necessarily like, you know, just sending us to a school that doesn't have a roof that's about to fall down on the children's heads. I mean, doesn't that make a difference. Yeah, If it made a difference, it ought to account for variance. And what I see with the high hered abilities, especially in England, is maybe it's telling us that schools are probably good enough.

They're allowing most kids to do their thing. You know, if some schools were particularly terrible and somes were particularly great, we'd expect that environmental variation to account for a lot of variance. And as I say, in England, where we have these excellent on site evaluations of schools, those ratings don't correlate with school achievement. You know, and you think of things like class size, right, how much variance does

class size explain? Very very little one percent? You know, So it's always plausible to think that these things make a difference. I think they matter a lot. You want kids to go to schools that have roofs more than that, that don't have bullying, that have good teachers. You know, you want schools to be a good place for kids to be, but not because the kids who get the better ones of those the better schools or whatever, that they're going to do better at these things. You know,

it's the difference between means and variance. I totally get what you're saying. Yeah, I totally get what you're saying. I'm trying to think of how, like, even if you're right, let's say that a child has a proquivity to be like very genetically to soak up knowledge like a sponge, like, how could it not matter that you have a teacher or a school system that is more likely to challenge and advance and accelerate that student. That's what I don't

understand well because I think it's mostly self driven. You know, it's a difference between instruction and education. You know, instruction really means you shove it into the kid, and that's the way a lot of people think about education, Whereas from this genetics of experienced perspective, I really think of education as education which means to educarrate to lead out rather than raw. So you give kids the resources, the possibilities for doing their thing, for learning what they want

to learn. And that's why I'm really excited about the possibility of personalized education and the potential that computers offer. You know, you see that with math. Now you know kids can with adaptive learning. They can go as far and as fast as they want. And the kids who don't do so well, who are slower at it, they can learn maths without failing a lot along the way.

In contrast to our current system where you get a teacher in front of a classroom, boring half the kids and over the heads of the other half of the kids. People in education get so upset by this, but got it makes such good sense to me free of the teachers up from this sorts of you know, stand and deliver sorts of lectures and let them help the kids who need more help, or, as seems to be the case in education, spend time with its. Behavioral problems are as big a thing in the schools as you know,

the actual learning process. So I kind of went far away from I think your initial point. No, and I agree about I think personalized learning is important, but I think that actually is consistent with my point that you know, teachers can make a difference, maybe just in a different way than people ordinarily think of. And also like there are lots of ways that we think they could make a difference, real they don't, and science can inform that,

like learning styles, training has been shown to be pretty bunk. Right, So anyway, I'll move on, and I'm going to put all these papers and I hope that, by the way, I hope this generates a good discussion. You know, I certainly don't have answers. I wanted to openly discuss this

in fascinating data with you. It's kind of interesting that, you know, I'm interested in the comments that come up as well, because we've done what do they call it a discourse analysis of the comments that have come up from the dozen things like you know, media presentations and stuff. And once you end up realizing it seems totally clear when you look at these like we had a thing

in the Daily Mail and something in the Guardian. These are you know, the major papers in the United Kingdom, and some of these had a thousand comments, you know, that sort of thing. It's so much a function of the context of whether the guy who writes it is writing kind of a balanced piece or writing you know, kind of an you know, an extreme view, and also

where it's published. And you know, so in the better places, you find that the comments are really, you know, very interesting, but the ones from the less good places, they're not even worth looking at. They're just arguing against, you know, in a really nasty way. You know. So that's why I'm keen to look at your comments, because I think you people, you know, listen to your sorts of blogs because they're you know, they're genuinely interested. They're not fanatics

pushing one view or the other. I hope that's the case. I really look forward to the comments too. So what about the very recent study I thought was interesting. Maybe you don't think it is as interesting as I did. Daniel Belski on genetic analysis of social class mobility in five longitudinal studies. I mean, we're talking about pretty well, I'm only reading to you studies that are like either

met analyzes or longitudinal across multiple samples. And they said, we tested if education linked to pologenic scores predicted social mobility in twenty greater than twenty thousand individuals and five longitool studies in the United States, Britain and New Zealand. Participants with higher pologenic scores achieved more education and career success and accumulate more wealth. However, they also tended to come from better off families, and this is the key test,

and the key test. Participants with higher pologenic scores tended to be upperly mobile compared with their parents. Moreover, ensibling different analysis, the sibling with a higher pologenic score was more upperly mobile. Thus, education, GENI and wide association discoveries are not mere correlates of privilege. They influence social mobility

within a life. Education GOS discoveries affect socioeconomic tament through influence on individuals family of origin, environments and their social mobility. To me, that is quite nuanced study, don't you think. Well, I'm glad you think so, because the first study and the one in the UK is our study. Oh y yeah. And so what we show is that you can define this as social mobility just in terms of educational intergenerational

transmission they call it. And so you can get kids who are have parents who go to university or not, and then some of the university educated parents the kids don't go to university and some do. And similarly with the parents who are on didn't go to university, some of the kids go to university and some don't. So we looked at the polygenic scores of these kids and what you find, of course, is that the university educated parents their children have higher polygenic scores, substantially on this

eighth educational attainment polygenic score. But what was really interesting, I thought was that you can look at downwards social mobility, look at the it's who didn't go to university whose parents did. Their polygenic scores are right in the middle of the other two groups. And similarly, the kids whose parents were not university educated who went to university had non significantly different scores, so you got you know, they're

in the middle. And what I like about that is to point out to people that social mobility isn't just upward social mobility, it's downward social mobility as well, which is really important. So I agree completely because you know that we I think we did the first study of that sort very cool, and I agree with Paige Harden's conclusion on this that that shows that by controlling for genetics, scientists can more clearly, see that our fane life is

already determined by how much money our parents have. You know, you can control. You can take people with the same exact pologenic scores and show, you know, that's the one person going to have a much harder time getting rich as an adult when they're born in a world class family than someone with the same exact score who was born in a higher social class. I mean, don't you think that that is relevant? Absolutely right, you know, that was the point of what we were trying to say.

But I think it also ties in with something I think is important if people are understanding all of this to say, I think heritability is an index of social mobility educational opportunity, because if you get rid of the environmental differences like privilege and wealth, you're left with the genetic differences. And it's also a reason why I think we don't have to worry about genetic casts. First of all, half of the variants is not genetic, and I think most of that is non shared, which I think is

essentially random and still castic. And that there should be social downward social mobility as well as upward social mobility. You know, so anyway, it raises a lot of value, big issues to talk about. But I'm really keen on

doing this sort of work my twins. Now that this twin study of ten thousand pairs of twins that I studied began when they were born in nineteen ninety four to ninety six, they're now in their twenties, and I'm really keen in We have DNA on those as well, So we're really keen to ask these sorts of questions about cool not just university education, but what about emerging adulthood and how people sort themselves out in life? Yeah, because we don't know much about it now We've got

this period from twenty to thirty. You know, it used to be like you know, Bruce Springsteen, you know, after school, high school, you get married, have kids, get a job for life, end of story. But boy, it isn't like that anymore. Yeah. Good, And I'm totally I am curious about everything. So I'm very curious what you find in this further research. So I'm going to end here with one last major point. So this idea of going with

the grain in large, I agree with this idea. You know that to me, like one of the biggest factors in pol psychology research, predicting life satisfaction is just simply self acceptance, right, So this seems to delvetoe is in a way with your message. However, some things we don't want to go to the grain against. And I think the big question and some reaction from your book is what is that wiggle room that we can have to change the parts of our personality and that we don't like.

And I came across this Brent Roberts meta analysis, a systematic review of personality trait change through intervention that does show that there are things like therapy matters. You know, therapy makes a difference. In fact, it doesn't just matter, it makes a difference in our personality traits. Anxiety disorders

shows the largest effects emotional stability can be influence. So I just want to end here with a message as well that I think your book does show that DNA matters, but I think they're all this kind of merging research shows it's not everything right absolutely, And you know, I've tried to emphasize that in the book, that we're talking about things that make a difference. Now that's what is we're describing. What is you're talking about what could be

and there's no necessary relationship between the two. So I have a very high polygenic score for body mass index, and if you could see I've also got a belly to go with that a bit, you know I'm doing it again. I'll take a screen capture which is moderately obese. But knowing that I have this even higher ninety fourth percentile polygenic score, it doesn't say, oh, I give up, I'm a genetic fatty. It actually is motivating. I say, I'm not doing too bad at the seventieth percentile. But

it also means I've got a lifelong battle. It's not just losing the six pounds I gained the last Christmas. I've got a constant battle. I put on weight easy and easily, more easily than other people. I don't lose it as well, And I need to control my environment so that I lose weight. So if that matters to me, I can lose more weight, you know. And so I agree completely that it doesn't mean you can't change, and in some ways I think it might help you with

some of these changes. So I agree completely that you can't and change behavior, and maybe we all need to be doing CBT come to behavior, therapy as a prophylactic, and you know, meditation has been shown to I think that meditation actually affects that pool of our genes and it gives us kind of a space between that pull

and our action. Yeah, it's probably good for everyone, but if you knew that you were particularly vulnerable to stress or whatever, maybe that would most You know, we all know you're supposed to eat well and sleep well and exercise and be mindful. But you know, we'll get around to it. Sometimes you know, you just don't actually do it. But maybe knowing about the genetics could actually help you, say, you know, I really ought to do this. Thank you, Robert.

Well indo there. You know. I know that we had some hairy, contentious moments in this chat. I thought it was great. I mean, this is nothing Scott. I think it bothers me more than it bothers me. Well, no, I love this too. Who's knowledgeable? You know what? I don't like out of these media interviews, But people don't know anything, you know, so it's wonderful talking to someone who's so knowledgeable about this stuff. I would like to say that if you get a lot of comments, maybe

we can have a follow up conversation. Yeah, that's entirely possible. The rest of the statement I wanted to say, though, is despite some potentially contentious moments, I want you to really know that I respect your work immensely and it has influenced my own work and intelligence. And as we move forward, I'm glad that you're opening up these conversations because I really do think we need to have very honest conversations about the potential implications of this data that's

going to come out. You're right, it's going to come out either way. So thank you so much for chaling with me today. Well, thank you, it was really terrific talking to you, Scott Likewise, I hope we do it again. Yeah, likewise, thank you. Okay, thanks for listening to the Psychology Podcast. I hope you enjoyed this episode. If you'd like to react in some way to something you heard, I encourage you to join in the discussion at thus Psychology podcast

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