Political Genes

Early in ’08 I posted on how our genes influence our political beliefs.  New data suggests gene influence is even stronger than it seemed then. Here is the fraction of opinion variance explained by genetics on various 1986 topics, for men and for women (all are 5% significant):


As I said back in ’08:

Unless you have a good reason to think your genes tend to produce more informed beliefs than other genes, you should reject the genetically-caused parts of how your beliefs differ from average beliefs. … Having an intuitive feeling that your belief causes are better is not a “good reason” if most everyone has a similar intuitive feeling.  The fact that you have specific reasons for your specific beliefs is also not good enough – most everyone has specific reasons.

Look: how your opinion differs from average on strongly genetic questions was largely determined by a random gene lottery.  That can be a fact about who you are and what you want, at least if you don’t mind your wants being random, but it just can’t be info about how the universe is or what it wants.  You can think you just like or don’t like school prayer, but you can’t reasonably think that feeling is informative about what policy is best for the country, or morally right.  More about the new study:

Variance components estimates of political and social attitudes suggest a substantial level of genetic influence, but the results have been challenged because they rely on data from twins only. … Moving beyond the twin-only design leads to the conclusion that for most political and social attitudes, genetic influences account for an even greater proportion of individual differences than reported by studies using more limited data and more elementary estimation techniques. …

The data we utilize … known as the “Virginia 30,000” … were … approximately 30,000 adult subjects (aged 18–84 years) were twins (N = 14,781), spouses (N = 4,391), parents (N = 2,360), relatives (N = 195), offspring (N = 4,800), and non twin siblings of twins (N = 3,184). … The inclusion of nontwin relatives is especially helpful in identifying the multiple sources of biological and cultural inheritance. …

The social and political attitude measures were included in a 28-item contemporary attitude battery gathered as part of a larger “Health and Life Styles” inventory conducted in 1986. … Data were collected by mail. … Two years later, the same attitude items were included in a follow-up questionnaire … providing measures of attitude stability for 1,019 men and 2,912 women.

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  • Carl Shulman

    Robin, IQ (especially) and education are quite heritable in rich countries for middle class folks, and have huge effects on political opinion, as Bryan has documented. Not to mention that a *lot* of issues come down to “like or don’t like.” The real fraction of variance explained by more bias-like effects is going to be a lot smaller than that table suggests.

    • Having the genes that determine political beliefs also determine IQ doesn’t undermine the argument. Knowing that a belief correlates with IQ could mean that the rational belief that averages over different opinions gives more weight to the higher IQ side. But you still have no good reason to deviate from that average belief; your inclination to do so is just due to a random gene lottery, and not due to info about reality.

      • Grant

        If a propensity to hold correct beliefs is heritable, then we would expect this trait to affect political beliefs as well. I’d imagine individuals with a higher IQ tend to hold more correct beliefs than those with a lower IQ. Individuals who correctly know they are more rational than others should probably place more faith in their beliefs, political or otherwise.

      • Jess Riedel

        Grant, you should read Robin Hanson’s comment more carefully. If we know everyone’s IQ, and we believe we know how IQ effects the likelihood of someone having true beliefs, then the rational belief is to average over the population’s beliefs while weighting according to IQ.

        In other words, having a larger IQ than average might let you weight lower-IQ people less and higher-IQ people more, but it *doesn’t* let you put more confidence in your beliefs than the beliefs of others who differ with you but have similar IQs. Further, you must to some extent defer to everyone who has a higher IQ than you.

      • Constant

        Jess, Robin is asserting the claim that if the difference between your beliefs and average beliefs is largely determined by a random gene lottery, then you should rationally reject the genetically-caused parts of how your beliefs differ from average beliefs. But your beliefs about IQ test answers are largely determined by a random gene lottery, since these are logically related to your IQ, which is largely determined by a random gene lottery. Should you reject the genetically-caused parts of how your beliefs about IQ test answers differ from average beliefs? This would seem to recommend that people with high IQs replace the answers they are inclined to give with average answers, to bring their IQ down to 100.

        I think IQ is a counterexample to Robin’s claim. IQ is largely genetic, but people with high IQ should not try to eliminate the genetic aspect of the difference between their answers and average answers.

        Now, Robin does have an escape conditional, which blunts the force of his core claim. He says, “unless you have good reason…” which allows someone with a high IQ (or good political instincts) to ignore the average and keep on thinking his genetically superior thoughts, on the grounds that he “has good reason”. But this only shows up in the earlier quote. In the newly written text he does not repeat that conditional. He quietly drops it, strengthening his claim to: “it just can’t be info about how the universe is” – from which he offers no way out.

      • Grant


        I did read it carefully (more than once), though may have missed his point.

        I understand and agree with what you are saying, however IQ does not seem to have been taken into account in this study? So we don’t know what beliefs may be due to some people simply being smarter, and what may be more directly heritable.

      • Anonymous

        Then what is the MOST reliable way avaliable to gain accurate political beliefs, or at least compensate for genetic biases?

    • michael vassar

      Not to mention that integrative complexity, openness and cognitive reflection are probably largely inherited and IQ and education of social group is largely caused by IQ.

  • Phil

    I don’t get it. Have they discovered a gene that’s linked to segregationism? How did they determine these r-squareds?

  • Perhaps this question is answered on the other side of the link, but lots of the things listed above don’t seem to map to the political sphere properly. Maybe the question was more subtle than that, but on say, abortion: does anyone “like” abortion? It seems like the question is whether to allow it or not, not whether or not people like it.

    Or take modern art, or pornography, or school prayer: someone might not like it, but feel that we should allow it. But my question comes up when I think about how these beliefs might have been acquired evolutionarily — I can see “don’t like, don’t allow” (or “like and allow”, or even “like, but don’t allow”) being selected for, but I’m not sure how “don’t like, but allow” would arise.

  • db

    I’ve changed my mind on many of these. And public consensus on even the strongly genetic school prayer has changed a lot. I know that doesn’t disprove that there is a strong genetic component, but I’m skeptical that the genetic effect is operating at the level of the issue. I could see genetic higher order values, such as equality vs. meritocracy or what have you, but I’m not sure what this issue by issue genetic rating is really capturing.

    • vjl110

      “I’ve changed my mind on many of these”

      That is to be expected. However, for most people the shift will be towards their parents views. Heritability for nearly every behavioral trait increases with age. Thus, we should expect a lot of youths with reactionary political attitudes that grow up to be just like their parents.

      I agree with you on the “higher order values” take. I would bet the heritability would be even higher if we could isolate what these are. It would be interesting to see the heritability with one of Jonathan Haidt’s moral value tests, which supposedly underlies most political positions.

  • Amasa

    But if these beliefs have a genetic component, then they might be selected for, which means that having such beliefs might make one more fit in certain conditions, which is surely a strong argument for having them? Or at least an argument against the beliefs being “random” (without, of course, any bearing on their truth).

  • dzot

    Homo Hypocritus does not hold opinions based on a random genetics. Everything we believe is the result of rational analysis.

  • quanticle

    If political beliefs are so strongly influenced by genes, then how can political consensus change on a non-geologic timescale? I mean, in a matter of forty years, we’ve gone from segregation and white supremacy being acceptable to them being almost totally verboten.

    How does that happen if genes are such a strong influence? At the very least, there should be a significant sub-population that still thinks segregation is acceptable.

    • Carl Shulman

      Changing social norms and economic conditions change views almost across the board, with genetic (personality/intelligence/height/appearance) influences affecting where people fall relative to the new normal.

  • Buck Farmer

    Robin, you’re showing your meta-ethical hand:

    “That can be a fact about who you are and what you want, at least if you don’t mind your wants being random, but it just can’t be info about how the universe is or what it wants.”

    The Universe doesn’t want anything. Teleology is not a very defensible position, and once you’ve retreated from it you’re left with locating goodness either relative to people or independent of people.

    I’ve not seen any compelling arguments for intrinsic good, and so think the person-relative good position makes more sense.

    However, once you’re at person-relative you’ve got to decide what you’re going to count as a person. So your beliefs are in part determined by genetics. Is that any less random or more random than your beliefs being determined by environment?

    Genetic influence seems a lot more comprehensible and predictable than environmental. If you accept that what makes up a person is very messy, but you insist that these people articulate their messy selves in rational, inter-subjective (objective?) ways, then you’ve got a workable basis for person-relative morality.

    Your anxiety about the messiness of what makes up humans seems to reflect a yearning for a human independent morality. In short, you want god to give you certainty.

  • Philo

    “Look: how your opinion differs from average on strongly genetic questions was largely determined by a random gene lottery.” “Largely determined”? What, exactly, does that mean? My opinions have been produced by many factors besides my genome; what is especially “large” about *its* contribution? And how do you know how any particular opinion of mine was actually produced? (1) I think you are just guessing that my genome had a “predominant role,” and (2) I don’t understand what “predominant role” *means*.

    If I have plenty of evidence that I am more intelligent, more knowledgeable, more thoughtful and less emotional than most other people, must I not repose more confidence in my opinions on issues I have studied and thought about than in the opinions of random other people–regardless of any population-wide correlation of opinions with genes?

  • Unless you have a good reason to think your genes tend to produce more informed beliefs than other genes, you should reject the genetically-caused parts of how your beliefs differ from average beliefs. …


    If I find that my taste for spicy food has a genetic component, does that mean I should stop eating it so much and make sure I only eat it the average amount?

    Politics is a way of expressing collective preferences. Why does it matter if some of those preferences have a genetic component?

    I distrust those numbers for some of the reasons given above by otherse. But say they are accurate. In that case, you conclusion doesn’t seem to follow, but these might:

    – political argumentation is somewhat futile
    – society should be more libertarian, to allow people with divergent fixed desires to realize them.

  • yay!

    You need to be very careful about these sorts of inferences. Saying “oooh, this opinion has a heritable component!” is pretty meaningless unless you know something about the underlying mechanism. Maybe some people’s genes predispose them to become better-informed about some issues. Maybe especially tall people, or beautiful people, or disabled people, tend to end up with the same opinions because they tend to have similar experiences (and their physical traits are heritable). Also, don’t neglect the role of epigenetics; with adoption studies, the uterine environment is still shared and this seems to strongly influence development.

    Opinions do have to come from somewhere: pointing out that an opinion has a cause doesn’t validate or invalidate that opinion.

    • dWj

      I think this is an overstatement, but I do think it would be interesting to see these numbers “adjusted” for race, hight, etc., i.e. to look at the variance conditional on those factors. Particularly for Party ID, I could easily imagine the entire genetic component being explained by race.

      It should be noted, too, that these are essentially descriptive statistics; if your population is selected for things that correlated with the relevant data, you’ll change the variance explained. The deeper content is in the fact that these are nonzero, which refutes any position that requires that they be zero.

    • KrisC

      I think the role of epigenetics needs another look as yay! says. I’ve long suspected that the conservative political viewpoint may be the result of the critical population switch -studied in lower organisms- causing the expression of a boundary guarding behavior.

      Then again maybe I should consult my DNA…

  • Amasa, the mere fact that you exist selected your genes were selected for. But this is true of everyone who exists as well; it doesn’t prefer you over them.

    quanticle, strongly genetically influenced beliefs can still respond to social changes. We might, for example, be genetically primed to take a certain percentile-rank position on an issue, but not care so much were the median opinion lies.

    Philo, relative variance explained is the meaning of “largely determined”.

    yay, saying “you have to be very careful about” seems an excuse to ignore inconvenient evidence. Your maybes don’t undermine the argument; even if they are true, the argument holds.

  • Political opinions are not facts. It is quite understandable that individuals with different genotypes and phenotypes come to differ on such matters. For example:

    “Gay rights” is listed – and gays might have a different opinion on this matter from straight folks.

    “Pacifism” is listed – but promoting this is not equally in everyone’s interests – since those with burly phenotypes would probably do relatively better in a world of conflict – and so on.

  • David Jinkins

    “You can think you just like or don’t like school prayer, but you can’t reasonably think that feeling is informative about what policy is best for the country, or morally right.”

    It seems to me (ha!) that fundamental values are indefensible. For instance, the popular American view that men and women should be treated equally under the law may be rejected in other places in the world. I suspect that such disagreements are not over the effects of policy on society, but rather over more fundamental worldview. I don’t think a typical American and typical Saudi would get very far discussing such an issue.

    “Morally right” is always supported in the end by feelings about values and worldview. It is perfectly acceptable to use the sort of ethical intuition you dismiss here in defining what is right and wrong. In fact, it is really the only way to defend your views.

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  • What are V_AM and V_AF?

    • V_AM and V_AF are the male and female fraction of opinion variance on a topic explained by genes.

  • Constant

    “Look: how your opinion differs from average on strongly genetic questions was largely determined by a random gene lottery.  That can be a fact about who you are and what you want, at least if you don’t mind your wants being random, but it just can’t be info about how the universe is or what it wants.”

    If the average is easily misled by liars (for good evolutionary reason – a survival advantage in swallowing the lies of the powerful), but you are difficult to fool (also for good evolutionary reason, this being part of an alternative successful strategy), then your opinion will differ from the average for the genetic reason that you are more difficult for liars to fool. Your beliefs are information about how the universe is. Indeed, the difference between your beliefs and those of the gullible is information about how the universe is. This is true even though you were randomly assigned non-gullibility. 

  • Robin’s already said it, but it doesn’t seem to be getting through, so I’ll flesh it out with an example.

    Heritability means the fraction of variation in some observable trait — height, IQ, pol. beliefs — that is associated with genetic variation among those being observed. It says nothing about the mean.

    Height is highly heritable, let’s say 0.7. That says that much of the variation we observe among individuals for height is associated with genetic differences among them. It doesn’t say that a particular individual’s height is such-and-such percent genetic — variation is only defined for a population. And it doesn’t say that the average height couldn’t go up or down without massive genetic changes — variation is not the same thing as the mean.

    For example, let’s say we observed a starving peasant population where height was 0.7, and overnight we gave them plenty of animal products to eat instead of mere corn and potatoes, as well as antibiotics, DDT spraying for malaria, etc. Within a single generation the average height would increase, without any change in the genetic composition of the group.

    Think of the relevant genes as genes that enhance your height above the group average. That average may be influenced by all sorts of non-genetic factors, of course. But if you’ve got lots of height-enhancing genes, you’ll be much taller than others in the group no matter what its average is. Same for genes that make you more permissive toward drugs, death penalty, etc. — that is, relative to the group average, as influenced as that average may be by non-genetic changes in the population.

  • Something to think about here is why some heritabilities are higher than others. Usually, that means that natural selection has not operated on that trait for very long, or that it has but only with weak intensity. A strong selection pressure lasting a long time will make the heritability fall to 0, either because there is no more variation in the trait (like we all breathe air), or because there are no more genetic variants affecting the trait that could be driven up (if helpful) or purged (if harmful), so that whatever variation still exists would be due to non-genetic differences.

    Ask yourself whether or not you could explain these political belief differences to a hunter-gatherer. Then ask how strong the H-G’s beliefs would be. If they would immediately understand the topic and have strong beliefs, this topic should show lower heritability in modern groups. If they had no clue, it should have higher heritability. That looks about right, although it’s not a perfect match.

    For example, beliefs on divorce show low heritability — an H-G would know what divorce is and have fairly strong opinions, suggesting that these beliefs have mattered more to natural selection. Try explaining X-rated movies or prayer in public schools to an H-G — it’ll take some effort. These things are very new, only on the order of decades, so natural selection hasn’t had much time to work on them (if they matter at all), which leaves the heritability high.

  • lemmy caution

    Peoples preferences are still their preferences even if they are genetically determined. I would bet the political phenotype for “cryogenic freezing” has a big genetic component. Are you now supposed to move your opinion toward toward the average opinion to compensate?

    People attempt to adjust their environment to be comfortable given their natural tendencies. Introverts like to have books around; extroverts like to be around parties. Political preferences may be a, mostly futile, attempt to adjust the environment to match people’s natural tendencies.

    It is interesting how low the genetic component to party ID is.

  • Cool. Let’s try not to forget this in the bloggy interim before the next publicizing round of information on the highly genetic nature of political belief.

  • Stuart Armstrong

    You can think you just like or don’t like school prayer, but you can’t reasonably think that feeling is informative about what policy is best for the country, or morally right.

    The correct (though indigestible) formulation would be:

    You can think you just like or don’t like school prayer, but you can’t reasonably think that feeling is informative about what policy is best for the country when all the impacts of school prayer are totaled up, or, if you are a moral realist, morally right.

  • John

    It seems like half the comments here say something along the lines of “maybe the genetic lottery is a big part of most peoples’ political beliefs, but I feel very certain that my views are right, and equally certain that others have simply been deluded or are ignorant or stupid.” Not to belittle anyone here, because the average comment here demonstrates a level of intelligence that is way above the internet mean, but isn’t certainty that our opponents are knaves or fools one well known bias that we all might try to overcome?

    • John

      One more thing directed at those commenters asking about personal preferences (for spicy food, or cryogenics):

      Some part of political debate is subjective (“I don’t want to live around gay couples”) and another part is objective (“gay marriage will end life as we know it”). Perhaps it would be wiser to change your beliefs about the consequences of a political position to be closer to the norm, while leaving your personal preferences unchanged.

      For example, say you have an objective belief and a subjective preference:
      1. Mixing purple and brown yields green.
      2. I like green.

      Everyone else, however, has the following belief and preference:
      1. Mixing blue and yellow yields green.
      2. I like purple.

      One might be wise to change one’s objective beliefs to fit the norm (deciding that blue and yellow may indeed make green), but one’s subjective preferences (liking green) should obviously not be affected.

      In other words, keep on eating spicy food if you enjoy it, but don’t believe that spicy food cures cancer. As for cryogenics, part of Robin’s desire for freezing is doubtless based on subjective ideas about, for example, how much he’d enjoy experiencing a totally alien world in which everyone he’s known is dead. Robin probably also believes that he’s better informed about cryogenics on the factual issues, too, but his subjective preferences are enough to justify a significant departure from the mean opinion.

    • Constant

      isn’t certainty that our opponents are knaves or fools one well known bias that we all might try to overcome?

      On that. Suppose that the population is divided into fools and sages. Suppose, furthermore, that Robin offers sage advice when he counsels adopting the average view. The sages follow Robin’s advice and adjust their views to reflect the average of all views. The fools do not follow Robin’s advice, and fail to adjust their views. With each iteration, the average approaches more and more closely to the views of the fools, until, finally, everybody comes to adopt the worldview of the fools.

      To put this story in a different way. Either you are are a sage or a fool. If you are a fool, you are cooked, you are done. You may as well not listen to the sages, since you can’t ultimately escape from your foolishness. You may as well wallow in it. And in any case, you’re not even listening, so there’s no point giving you advice.

      If you are a sage, then you should not listen to the fools, since they are fools. You should not average your views with the views of fools, since that would increase your foolishness.

      So no matter who you are, either you may as well treat the other side as fools, or else you should treat the other side as fools.

      Finally, if you want to contribute to the advancement of knowledge, the last thing you want to do is adopt the average view. The average view is not on any frontier of knowledge, so if you adopt the average view, then you will never contribute. If, on the other hand, you go out on a limb, then even if you are on average more wrong, if, say, you are more wrong than everybody nine times out of ten and more right than everybody only one time out of ten, then that one time you do contribute to advance, and the other nine times you hardly do any harm, since others will recognize your foolishness. Look at Isaac Newton. He was was not right about everything (e.g. he was interested in alchemy). Maybe he was more wrong than right. It doesn’t matter. We have separated the good from the bad and preserved the good ideas of Isaac Newton.

      • If the world were this simple, it would easy for everyone to tell if they are a sage or fool: you are a sage if you feel inclined to be persuaded by my argument. Given this key info, fools would know to ignore their initial opinions and defer to sages, at which point all would agree.

      • Constant

        The simplified model is there to make the point clear. In the real world the fools do not know they are fools, and therefore, to make the model a better microcosm of the real case, we must likewise assume that the fools do not know they are fools. 

      • Constant

        (Actually I think that you (Robin) must be kidding, but it’s hard to read sly humor in text – hence my straight response.)

      • Constant, if they fools do not know they are fools, then they can’t tell they are fools from whether or not they are inclined to follow advice, so you can’t assume the fools don’t follow your advice.

      • Constant

        The fools believe they are sages and believe everything sagacious -including your advice – is foolish. They believe that their failure to follow (what they wrongly believe to be) foolish advice is consistent with their sagacity. The fools and the sages have their categories reversed.

        If this is insufficient explanation, I will drop it here and possibly take up the matter at a later time with a more acceptable thought experiment. 

  • “You can think you just like or don’t like school prayer, but you can’t reasonably think that feeling is informative about what policy is best for the country, or morally right.”

    You *can* think that – if your aim is to manipulate others into adopting the same views. If you don’t really think it is the best thing for them, others are likely to detect your insincerity – and then resist your attempt to manipulate them. So: it is best to believe sincerely in the worth of your political opinions – if you want to spread them around so that they come to matter.

  • Dan in Euroland

    For those without access I believe the title is Not By Twins Alone and the pdf is here.

  • Alex Flint

    I think these types of studies can warn us about which of our beliefs we should inspect particularly carefully, but at the end of the day the best we can do is to apply our reasoning abilities as carefully as possible. There is no sense in saying “well I’m genetically pre-programmed to believe that 2+2=4 so the fact that it seems intuitively logical is no reason to believe that it’s true”.

    Also, some of these correlations might not imply causation. 400 years ago (and perhaps to this day) there was probably a strong correlation between skin colour and belief in the experimental method, but that’s not because Enlightenment thinkers were genetically pre-programmed to believe in the experimental method.

  • A big problem with this study is that it conflates “genetic” with “in utero environment”.

    Monozygous twins share not only the same genome, they also share the same in utero environment where 99.9999%+ of their growth and development occurred (from a single cell to 10^8+ cells).

    This is a gigantic problem with twin studies that is mostly ignored.

  • Tony

    It is important to distinguish between “heritable” and “genetic”.

    First off, epigenetic factors – these are both environmentally influenced AND heritable, and their influence on cognition is a hot topic right now, particularly the role of DNA methylation.

    Also, there is a huge “heritability gap” – even though we know many traits, like propensity for diabetes, are extremely heritable, we have been unable to link these traits to _specific_ genes or features in the genome. This is a big puzzle right now, and it may be that our perspective on what it means for something to be “genetic” is way off base.

    Please, please use the term “heritable” when that’s what’s observed, because calling it “genetic” is quite premature.

  • Because there are millions of common SNPs, CNVs, and other genetic variants in humans, it is possible to attribute 99% of any attribute to genetic variation, unless you have a sample size in the millions (possibly fewer, possibly much more). So it’s crucial to know how the study controlled for multiple hypothesis testing (meaning, if the first gene variant you try fails to account for the data, you can move on to the second, and the third, and the millionth.)

    • Because the study was a twin study, my comment above is irrelevant.

  • Please provide a reference. The link you provide merely leads to a nag screen, with no information as to the authors, journal, or year of publication.

  • Stephen J. Hulbert

    Are there any good books about the relationship between genes and politics?

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