Behavioural genetics: should we be worried?

Eugenics got a bad name after the second world war. It got associated with pseudo-scientific theories under which people at the bottom of the societal ladder were branded as hopelessly deficient for supposedly inalterable biological reasons. Societies’ less successful were, quite literally, seen as ‘untermensch’ (under-people) and the ‘science’ of heritable poverty, height, and intelligence was used in the public campaigns of the nazis and others to stigmatise gypsies, jews, homosexuals, vagabonds, and others as being biologically deficient and hence a kind of ‘disease’ for which the only ‘cure’ was annihilation or selective breeding.

Modern behavioural geneticists of course are not like the old eugenicists. They are ‘merely’ looking at the relation between genetic proximity between people and how much their height, their intelligence, their mental disorders, their criminal behaviour, and their body size resemble each other. They talk of alleles, single nucleotide polymorphisms, linkage disequilibrium, heritability, phenotypes and CNVs, not the inherent inferiority of this recognisable group of people over that group. They do not advocate selective breeding, unless it is of mice or plants of course. One cannot find a single paper by behavioural geneticists in Nature or Science, where they appear often, that calls for genetic tests to be used for potential migrants or selective baby-bonuses.

And yet, I find this field somewhat creepy in its treatment of social processes. The same techniques and language is used to ‘track genetic diseases’ in plants as is used to track ‘genetic causes of behaviour’. The same techniques of breeding ‘mice with particular traits’ is advocated to ‘find’ the biological basis of what are essentially social outcomes . The same old penchant of looking for supposedly inalienable biological causes of what are changing social constructs is on display.

The literature I am talking about is vast, and the interested reader is invited to look at some reviews of it here (written by insiders of this literature), or else by psychologists here. There is little point in regurgitating those reviews, which are both very informative and open-minded. What I will do below is say why I think you don’t actually have to worry about this crowd: yes, these geneticists are indeed looking for the genetic recipe of the successful human, but their quest is, at the moment, going nowhere.

The view of humanity that emerges from some behavioural genetics is one whereby there is a strong and virtually direct genetic causality of nearly all social outcomes, independent of local environment or social processes. See page 8 of this explanatory note for the latest techniques used in the modern Genetic Complex Trait Analysis (GCTA) studies, involving direct genetic causal effects and an ‘error term’ which captures all the rest. Their statistical models encapsulate the idea that the successful are successful because of their genes, the poor are poor because of their genes, the stupid are stupid because of their genes, the small are small because of their genes, the schizophrenics and autists are thus due to their genes, etc. Everything else is an ‘error term’ that is presumed completely unrelated to genetics.

Let us not mince words: I see this as a dog-breeders view of humanity, where traits can be bred by combining dogs with desirable trait and discarding the other dogs. The important questions for the modern genetic dog breeder is then one of finding the particular genes that cause the particular outcome. Once one has found these, the optimal breeding program can be guided more efficiently. Or, less dramatic, particular ways can be found to ‘improve the functioning of this or that gene’ to get the desired outcome. I shudder to think of the fate of the other humans if the recipe for the successful humans is found. So I sincerely hope this recipe is not found. I hope it doesn’t exist either, but that is another matter.

Let me give you some of the good news immediately: according to their own methods, that of linear additive effects of a million genetic variations (single nucleotide polymorphisms, SNP, in their lingo), people can become as tall as a tree or even attain a negative height. The fact that you don’t see this is in their view because of the pure accident that no human has yet been fortunate enough to get all the good genes, nor unfortunate enough to get all the bad ones. In reality it is of course because their methods are not, strictly speaking, correct but merely approximations of deeper complexity. So forget about seeing these geneticists as dealing in the pure scientific truth. If you thought that, you have been duped.

Let me give you even better news: despite grand claims in their papers that behavioural geneticists have ‘explained’ 70% of human variation in intelligence, height, etc., this is not actually the case. They have not found actual genetic recipes at all that explain this amount of variation. Rather, they infer from their techniques that an unknown combination of around a million small genetic influences should be able to explain 70% variation in intelligence, height, etc.

How does this ‘inferring’ work, you may ask? Well, it is a complicated statistical story of latent variables and association matrices, but the simplified version is this: they essentially count how many genetic variations people share over and above what they would randomly share as part of the same population. They then only look at people who are less close to each other than about 2.5%, which means close family is kicked out. So they look at humans who share around +1% or -1% of each other more than expected as part of the same population. They then find, on average, that people who are one percent more alike, are about 0.7% closer to each other in terms of outcomes, whilst those who are less like each other by an extra percent are 0.7% further away from each other. That 0.7% then gets blown up to 70% ‘variance explained’. So in reality you are looking at ‘explaining’ 0.7% of pair-wise variation, and even that is via an unknown combination of influences. In economics we would say that they have hit upon a ‘proof by error-term’. It is basically a con-trick.

What is wrong with that, you may ask? Well, for one it means one doesn’t know the genetic recipe supposedly responsible for outcomes, so the 70% is pure smoke-and-mirrors. Moreover, that 0.7% that the results are thus actually based on can come from a huge variety of environmental factors, such as historical advantages of this or that group making them higher and smarter because they had more training and more resources, not because of their genes. Genetic similarity might simply pick up a shared environmental advantage, such as belonging to particular ethnic or wealth groups, and that then gets hugely amplified. Statistically speaking, their independence assumption, ie that genetic information is not related to any form of relevant shared environment, is the thing that does the real work in their methods and it is ridiculous: how on earth one can have genetic similarity (via shared actual ancestors!) between people without the high likelihood of a relevant shared environment is beyond me.

Does this crowd not realise this problem? Well, again, they pull a couple of smoke-and-mirror tricks to bury this kind of issue. They talk a lot about G*E interactions by which they mean genetic influence that work in particular environments, but they dont really entertain the notion of interactions, nor do they really deal with the more fundamental possibility that one is essentially looking at pure E effects for which genetic information is then nothing more than a marker.

Why don’t they try and account for environmental factors, you might wonder? Well, for one, these techniques come from the world of plant breeding and animal breeding, where of course the researchers perfectly control the shared environment. There is no such thing as an advantage in terms of wealth or educational habits that is passed down from one plant to the other or from this cow to that one. Hence the problems of variation between humans throws up problems that don’t come up with plants.

Second, the business of actually accounting for environmental circumstances is hopelessly complex. After all, this is what economists, demographers, and psychologists have been doing for decades, and ‘we’ have been struggling to prove causality. Where-ever we look, we find incredible complexity and non-linear interactions. It is a nightmare to measure and analyse social data: it is exceptionally hard to measure ancestral wealth, educational habits, the geography in which people have lived in their lives, the people they have interacted with, the shared cultural and political environment they had, etc.

It is not just a lack of available surveys that nail down what you really want to know, it is also the incredibly complicated causal spaghetti that is the problem: with every ‘environmental control’ one would be trying to account for, comes in a whole set of measurement problems and of course the problem that an environmental variable might itself be merely a poor proxy for something else, as when the ownership of an umbrella might say more about the weather in the area than about the wealth of the owner! So it is quite understandable that these geneticists don’t want to have to deal with the issues that have bedevilled social scientists for decades, and thus shove those issues under the carpet. Indeed, even when they throw in a couple of environmental ‘controls’ they are still only scratching the surface of the difficulties. They would essentially have to solve all the problems of empirical social science on top of their genetic puzzles.

On the purely genetic side, there is more good news which is that they can’t find individual genes explaining much of intelligence, obesity, or mental health disorders. They hit false positive after false positive, by which I mean that a genetic variation accidentally found to relate to an undesirable outcome in one population turns out not to be related to the same undesirable outcome in another population. Indeed, the field has now turned to the somewhat hopeless hypothesis that there are no single genes or even small groups of genes responsible for low intelligence and other undesirable outcomes, but that undesirable outcomes are due to thousands of small negative and positive genetic influences on ‘performance’. I would call this the ‘death by a thousand cuts’ hypothesis. They tell themselves they will soon uncover all those thousands of small influences if other people give them enough money to keep going (which they probably will), but the outsider should see this emerging ‘polygenic hypothesis’ as great news. As Evan Charney says, they have been reduced to ‘chasing ghosts’.

Even if the ‘ghostly hordes’ materialise, finding them would make ‘genetic treatments’ or ‘breeding’ a virtual impossibility: the rate of new small genetic variations in each generation of humans would swamp the usefulness of knowing about today’s influences, and one would need a fantastical amount of embryos by potential parents to be able to select on just a few dozen of these small influences. Hence, in a way, the current state of that literature is such that their usefulness for potential breeders is very much in question.

The news gets even better. The supposed genetic causes of social outcomes turn out not to be constant over social strata. This is what the newer studies like the Bates 2011 study on the genetic causes of intelligence are about: they are finding that, unlike for higher socio-economic groups, genetic proximity doesn’t explain much of the variation in intelligence amongst lower socio-economic groups. Better still, those studies themselves appeal to the idea that the ‘real’ drivers of intelligence are learning (such as in university) and that the inability of genetics to explain intelligence amongst lower socio-economic groups is essentially because there is no genetic determinism of intelligence in that group, rather the determinants there are social processes. I am not a religious man, but it is a real ‘thank god’ moment, though of course the behavioural genetic literature as a whole might just shrug such studies off as blips on the road to finding the full genetic roadmap between genes and outcomes. Well, good luck with unpicking thousands of small genetic effects interacting with an ever changing social reality, I would say to them! It is the kind of Research Mountain that makes macro-economics look easy by comparison.

Another piece of good news is that they can’t be right at the group level: there is no way that genetic determinism really can explain, on its own, fast changes in group averages of the outcomes of interest. Unless one believes that aliens with different genes have surreptitiously invaded the planet, genetic determinism cannot explain the spectacular increases in obesity rates in our society, or the large increases in measured intelligence, or the huge decreases in crime rates, or the large changes in measured mental disorders. In essence, the behavioural genetics crowd is fairly impotent in explaining these changes in group behaviour, as of course also noted by other social scientists. The review in 2012 by the psychologist Nisbett and his colleagues into IQ noted this as an “apparent contradiction between strong heritability effects on IQ and strong secular effects on IQ”. Less nicely put: these geneticists cannot explain changing averages. Though some do try, and, as I have argued before in the context of obesity, their attempts to explain a change by something unchanging is going nowhere.

Which brings us back to dogs: the whole point of getting to know which genes lead to desirable traits is because one wants to breed particular average traits. The complete inability of the behavioural geneticist crowd to explain changes in group averages of traits is great news, in my opinion. Their inability to find the actual genetic markers that, across populations, would predict who is going to end up on the top of the social scale and who would end up at the bottom, is similarly great news. Their continued penchant to believe they will soon find the magic genetic formula that ties thousands of small genetic effects to thousands of interacting behavioural processes and other genetic effects is almost charming in its naivety. Good luck, I say to them.

So, at the start of my sojourn into this literature, I found the geneticist crowd slightly creepy in its penchant to treat undesirable social outcomes in the same way as it treats diseases. Having seen how little progress they have actually made though and how much less useful they are in coming up with policy levers than social scientists have been, I am breathing a sigh of relief. There will almost surely be some genetic influence on the distribution of social outcomes, and there are interesting puzzles in term of just how those influences go, but I see little danger at the moment that dog breeders will soon get a manual by which to ply their trade on humans. They might find a couple of genes for this or that mental trait, but the story that geneticists will soon know the recipe for creating a socially successful human being, should be seen for the consumptive fantasy that it is and looks to remain for the foreseeable future.

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41 Responses to Behavioural genetics: should we be worried?

  1. conrad says:

    The big danger is not that they can’t convince people like you, it’s that they can convince the public. I’ll bet they can. Exactly the same problem exists with brain imaging, where people want to dissolve poorly defined constructs into biological disorders based on minor differences in brain morphology or blood flow (and additive factors logic to determine the difference), and somehow it seems more believable if you put some nice brain scans in. That includes for grant funding too unfortunately — at least in psychology, it will be interesting to see if the Libs chop “social science research”, which has pretty much found all the useful finds on teaching, parenting, … etc. and leave brain imaging and genetics (which will be left, as much of the funding is from the NH&MRC which will benefit from the ARC’s loss), which, as far as I can tell, have found basically nothing of use to anyone in any useful area even with low-level human behaviors (e.g., short-term memory). I can imagine the same thing happening with genetics — the public want simple stories to hard problems, and telling them “you are like you are due to genes A, B, & C” will make them happy, just like telling them that, say, having discalculia is caused by tiny morphological difference in their pariental lobes. You will then get more and more people working in the area (you can see the explosion already), and they well become an entrenched force giving out grants to each other.

    I also agree with you on the likelihood of finding anything more than mere correlations with the genes — as does one of France’s top geneticists (who’s name escapes me now :) who gave a talk a few years ago at the CNRS I work at sometimes. So you certainly arn’t alone, and many of the genetics people realize the scope of the problem too.

  2. Paul Frijters says:

    Hi conrad,

    yes, I wasnt convinced of this earlier when you said these things after previous posts, but having spent several weeks now pouring over their appendices and methods, I can now see where the rabbits get into the hat and where they have buried the skeletons when they do their dance for the general public. It never ceases to amaze me to see what people get away with.

    I find it a bit irresponsible of the major journal editors in science, really, to give so much space to this. After all, the older twin studies are more convincing and more useful than this GCTA stuff, but I guess one cant keep doing the same thing 80 years in a row. And you are quite right about public appeal: I can see this sort of stuff being quite popular for a while, particularly when it soothes people’s desire to blame something simple.

    But I am not sure they will win in the longer run. You see, I think some of these researchers wont be able to help themselves and will make big claims on an accidental coefficient, claiming that they can say which 20% of our society has an identified genetic reason for their low intelligence or their criminal tendencies, or whatever else. Then they might well come up against the egalitarianism of the nation state in a big way.

    • Expect that the illusion of hard science, will improve funding attitudes , for a while.

      The idea of a genetic level approach to things like IQ or social behavior involves a misunderstanding of something that is true: all life is ultimately based on inheritable genetic traits.

  3. Tel says:

    Eugenics got a bad name after the second world war.

    It was a time when bad reputations could be had for the taking…

    They do not advocate selective breeding, unless it is of mice or plants of course.

    Thing is that all breeding is selective, a fact that will never change regardless of what we do. The real question to be asked is, who gets to make that selection? I’m not upset if a woman or man might reject a potential partner, and look around for another… of his/her own choice. I am upset by the idea that some self-appointed smarty might get into the business of telling people which partners are suitable. Then again, I’d be equally upset if the same guy told me which job I should be doing, or where I should live, or when to wear a bike helmet. Individual decisions should be made by the individuals concerned, because those people will be responsible for the outcome.

    No doubt some are already accusing me of over simplifying a complex topic, but why make it more complex than it needs to be? The nastiness stems from one human’s life being manipulated by another, and this can happen in small and trivial cases, or it can happen in prominent obvious ways, or subtle sneaky ways. I guess one way or another it’s unavoidable, but we can work together to reduce the problem.

    Their continued penchant to believe they will soon find the magic genetic formula that ties thousands of small genetic effects to thousands of interacting behavioural processes and other genetic effects is almost charming in its naivety. Good luck, I say to them.

    It would be difficult to keep believing in Evolution, and at the same time not believe that research will adapt itself to fill the grant money available. Doubly so if you have some respect for the intelligence of the researchers.

    • Paul Frijters says:


      yep, you are right. Manipulation of people by people is normal and, indeed, breeding always is selective already. Indeed, from the point of view of the species, there is little to worry about here as a bit of ‘genetic tech help’ simply speeds up the selection process.

      So why am I against eugenics? It is the anti-egalitarianism of this that wrangles me. Being able to assign the label ‘hopeless’ to people at birth would create a further advantage of money, and a further disadvantage for the poor and the simple. And of course at the level of the species there there is no real benefit either (why would humanity as a whole care about average IQ or height?) so it is really just about the wealth distribution. I don’t want a kind of winner-take-all society and like the social norm in which people are of equal value.

      • A question, :-) All life is based in the genetic code , so why is looking for a genetic level explanation of things like IQ, not a good idea?

      • Paul Frijters says:

        Let me answer the question by posing a return one!

        All life is also based on water, and carbon, and particular cell-processes. Why dont you then research the importance of the qualities of water and the radioactive half-life of carbon on, say, the art scene in the deserts of Australia? Surely there is some connection? How do you know that connection is of less importance than social factors, say government subsidies?


      • Tel says:

        Would it be good enough to say that although manipulation of people by people happens often, we agree amongst ourselves to reduce it where possible?

        I can’t see a problem with allowing people to voluntarily take measurements of their own DNA, to discover whatever they want. There has to be an opt-out for people who would rather not know. The compulsion is the evil, not the action.

        Suppose a woman thinks she might be short. Maybe measuring her height and checking the statistics to compare against the national average would just confirm that she is indeed short, but then again some guy glancing across the room could also confirm the same. Are we going to start outlawing the measure of breast size because someone might feel inferior? The bra manufacturers will need to produce a one size fits all model… hilarity ensues.

        I guess part of the strict Islamic dress code is to prevent women comparing against each other, it makes sense from a certain practical point of view… but personally I don’t want to live like that.

        • conrad says:

          I imagine the contentious issues are what people choose for their children. This is clearly something we could do more of if it was easy. For example, I’m colour blind (certainly genetic), and miss two adult teeth (possibly genetic/environmental). If my mother did a genetic a switch with me and fixed these, I wouldn’t have complained. One of them I presumably couldn’t do yo myself as an adult (get my two teeth back) unless you turn me into a rabbit.

          Indeed, there’s any number of fairly trivial things you could change to make people’s lives better. Some of these don’t seem especially contentious (diseases, cancer genes and the like). However, let’s say I was going to be especially stupid, but that could fixed too. That would make my life a lot better, and presumably a fair bit of stuff is developmental, so you couldn’t switch it as an adult. So when does one decide?

          Of course, I don’t think we’ll get great measures of how genetics causes complex traits, so I don’t suppose I’ll have to worry about this. But I think it’s more complex than allowing people to modify themselves.

        • Gummo Trotsky says:

          However, let’s say I was going to be especially stupid, but that could fixed too. That would make my life a lot better, and presumably a fair bit of stuff is developmental, so you couldn’t switch it as an adult. So when does one decide?

          Fast forward to the year 2150; with the worst effects of AGW narrowly averted and a whole lot of progress in genetic testing for desirable/undesirable traits, your distant descendants Mr Conrad and his wife are talking to an obstetrician about the results of amniocentesis on their first pregnancy:

          Ob: It’s bad news I’m afraid. The results show that your daughter will have two undesirable and potentially disabling traits: an IQ of 150 and a strong aversion to dishonesty.

          Mr C: WTF! How can that be undesirable?

          Ob: consider how your daughter will get on with her less intelligent peers once she’s at school Mr Conrad? As for the aversion to dishonesty – do you think I would have reached my current position without a bit of judicious bullshitting on my resume? These traits will make her life a whole lot worse than it could be, believe me.

          Mrs C: Is there nothing that can be done?

          Ob: Well… it’s well known that consumption of alcohol during pregnancy will impair the cognitive function of the child after birth. However I couldn’t responsibly suggest that – however beneficial it may be for your child there are risks to your own health to consider. I think it might be better to terminate this pregnancy and try again.

        • conrad says:

          I’m quite aware that what we happen to think are positive characteristics in humans has differed markedly across history. These include intelligence, which I doubt having high levels of had too much use for most people until recently (although perhaps I’m being 21st century centric here).

          Alternatively, you might like to talk to people with verbal IQs of 70 and see how their lives are going (I think crap will be the general response). Even more simply, and philosophically more interestingly, you could look at people with selective language impairment who really would have verbal IQs this low. Now the genetic cause of some people with SLI is known and indeed in one case a single genetic error has been found (e.g.,, but for others that it isn’t (presumably a myriad of genes and environmental causes).

          Now, you might ask yourself, is it fine to fix things (if it could be done) with a single genetic cause, things with a myriad of genetic causes, both, or none? If I had serious language problems, I know which I’d choose.

        • Gummo Trotsky says:

          Alternatively, you might like to talk to people with verbal IQs of 70 and see how their lives are going (I think crap will be the general response).

          Actually, I think I might have encountered quite a few such people while I was living for a few months in a Supported Residency Service. Some probably with lower verbal (and general) IQs. Never got around to asking whether they thought their lives were crap(in one case you wouldn’t have gotten an answer anyway, such was the degree of verbal/cognitive impairment) but my observation was that quite a few were accommodated to the place, its routines and its strictures on personal behaviour. The discontented residents were those who’d seen better times and better ways of living.

          Let’s remember that IQ, as a measure of general intelligence, has only been around for a century. And that excesses of function in bodily organs – such as hyperthyroidism in the case of the thyroid gland or extreme anamnesis in the case of the brain’s memory centres can be just as harmful as deficiencies of function.

          And if your hypothetical distant decendant’s in utero daughter’s amniocentesis showed signs of sociopathy (rather than a pathological honesty) along with the high IQ, the obstetrician might not consider it a problem for her future health and well-being…

  4. Tim Macknay says:

    Paul, having read some of the literature myself, I’m in general agreement with you about behavioural genetics.

    I think though, that despite being a very long way away from achieving its stated goals (fortunately), behavioural genetics (as well as related disciplines like evolutionary psychology) still has the capacity to influence policy in negative ways in a way similar to eugenics.

    Bad science isn’t necessarily unpopular, and there’s something about the “dog breeder’s view of humanity” that seems to appeal to many people. As you’ve said, it took a holocaust to put eugenics out of fashion, and it seems that we’re now far away enough in time from that event for similar ideas to experience a resurgence.

    I’d also go a little further than you on Eugenics, and say that , rather than being merely “associated with”, Eugenics is a pseudo-scientific theory under which people at the bottom of the societal ladder were branded as hopelessly deficient for supposedly inalterable biological reasons. The science fiction movie Gattaca had an alternative credits sequence which contained one of the best illustrations of the limitations of Eugenics that I’ve seen – it said “if the eugenics practices depicted in this film had been in place during the twentieth century, the following people would never have been born”, followed by a surprisingly long list of eminent scientists, musicians, artists, statespeople, inventors and entrepeneurs, all of whom had congenital ‘weaknesses’ that, in all likelihood, would have resulted in them being “edited out” by any Eugenics regime.

  5. Tim Macknay says:

    Not sure why I capitalised eugenics in the last paragraph. Oh well.

  6. Jim Rose says:

    James heckman has written good stuff here, looks and the twins and adoption studies to cinclude there is still room to change things for the better

    • Paul Frijters says:

      Hi Jim,

      yes, the whole early-life development literature does suggest there is quite a bit up for grabs. This is partially why this psychological review I linked to (which goes over quite a bit of that territory: they preceded Heckman by decades in this area) declares itself a bit puzzled by these high heritability claims.

      Btw, so far you are looking good for the Egypt prediction. Early days yet, but still.

      • Jim Rose says:

        Heckman and bryan caplan come to different conclusions after looking at the twins and adoptees literature.

        Heckman wrote great reviews of the bell curve pointing out that all that matters is is there any environmental scope for change. The issue is then of cost benefit analysis

        On egypt, their security forces have rediscovered the ability to shoot to kill. They lost this skill during the succession struggle when it happened to make the ruler look weak!

  7. Julie Thomas says:

    “consider how your daughter will get on with her less intelligent peers once she’s at school”

    My daughter, a very high functioning Aspie – and she did get an official diagnosis during the time when it was a diagnostic category – was very unhappy at school and then later at work – she is a coder/developer – and claimed to wish she was ‘stupid’ because, she said, stupid people are happier; stupid people don’t know how awful things are.

    It seemed clear to me that the actual problem was not that she was more intelligent than her peers, but that she had a ‘personality’ that made her ‘difficult’ and created the difficulties she experienced in getting along with more ‘neuro-typical’ people.

    She is fine now. The diagnosis itself, the psychological therapy – 6 session – and the way that the genetic basis of Asperger’s type behaviour is recognised in the community now, have all meant that she ‘feels’ ok about herself now and is able to cope with ‘neuro-typicals’ and their weird ways.

    I also find that the widespread understanding that there is a genetic basis to our initial endowment of abilities has made my life as a recipient of a disability pension, better – I need be less defensive about my circumstances. People – well the women anyway – in my small community have found it easy to understand that genes are only the foundation of the person that develops from the baby.

    It seems to me that most people I talk to, unless they are ideologically motivated to believe that people deliberately choose to be stupid and lazy, do understand, easily, that it is a combination of upbringing – including environment – and genes that determine a person’s outcome.

  8. If high intelligence (whatever that is) is really a significant disadvantage – possibly true:-). Then Evolutionary theory says that it should be much rarer than it is, unless it is a acceptable i.e infrequent downside to some other related traits that confer,frequent, advantage to most.

    • Gummo Trotsky says:


      let’s introduce a little distinction here – between a heritable capacity to develop high intelligence and actual high intelligence – whatever that is ;).

      The first is an obvious selective advantage in whatever wild state we choose as ‘the original selective environment’ for the purpose of evolutionary just so stories. It ensures that adverse conditions such as malnutrition etc don’t result in adults so imbecilic that they’re incapable of recognising and running away from the sabre tooth cats or organising themselves to dig pit-traps for the wooly mammoths. It’s a redundant capacity that ensures adult survival and reproduction.

      Modern humans – particularly in the Western world – don’t live in that environment and good nutrition – among other things – means that a lot more of that redundant capacity is actually realised during development. You can observe something similar in domesticated animals compared to their feral cousins. But that’s getting off topic quite a lot.

    • conrad says:

      I’m not sure what evolutionary theory says about multifaceted complex constructs like intelligence. Probably not much very much apart from pseudo-science based on confirmation bias.

      If you want two very obvious and glaring examples of this, look no further than gay people and Europe and Asia’s current birthrate. I don’t suppose any evolutionary theory a-priori predicted these, yet we still seem happy to believe all the other stories if they sound right (Stephen J Gould’s why men have nipples comes to mind here too).

      This of course doesn’t mean there won’t be lots of variance between people caused by genetics on various constructs, just that knowing why is hard.

      • Flight is a “multifaceted complex construct” : feathers provably gave insulation advantages, light bones climbing trees advantages (or whatever).. and so on.. and then at some later point they were, adapted? …forgotten the term for it…. into a complex construct.

        Was thinking that ‘intelligence-brains’ can use a lot of energy and in some situations that could truly be a disadvantage (or of no advantage)… A bit like building arms and legs is a waste of energy for for some internal parasites.

        “gay people and Europe and Asia’s current birthrate” … please do explain.

  9. conrad says:

    I’m thinking mental constructs here. Feathers really do have an obvious advantage, and you can presumably even trace the success of them and thus get real and testable evidence.

    “please do explain.”

    Which evolutionary theory predicts that you should have members of the population that typically wouldn’t have propagated themselves, or propagate themselves at a level far lower than replacement?

    If the answer is, none of them, then why would you believe other claims on things far less obvious?

    • “Which evolutionary theory predicts that you should have members of the population that typically wouldn’t have propagated themselves, or propagate themselves at a level far lower than replacement?”

      A theory that predicts that if ‘it’ results in helping more , close enough relatives ‘kids’ to reproduce, its ‘inheritable’.

      PS I think that historically, it is provable that most gay (and ambivalent) people lived in married closets. It is a untested assumption that historically this situation equaled, no offspring.

      • conrad says:

        A good way to think about this is to give the alternative. Let’s say:
        1) Everywhere still had greater than replacement birthrates
        2) Gay animals were almost never found (no doubt many people believed this for a lot of history).

        I think it reasonable to suggest that people would assume, based on “evolutionary principles”:
        1) We have a strong evolutionary bias to reproducing, and so we have too many children
        2) We have a strong evolutionary bias to reproducing, so gay animals died out

        But clearly, we find just the opposite. Yet we still want to believe in evolutionary stories even when the data goes the wrong direction in what should be fairly clear-cut cases.

        Also — the idea that people were in the closet doesn’t really matter much to the argument, because gay animals (male ones at least) haven’t had to worry about this.

        • “1) Everywhere still had greater than replacement birthrates” is one of the 3 basic pillars of Darwin’s theory.

          “2) We have a strong evolutionary bias to reproducing, so gay animals died out”
          This is ‘theoretically’ incoherent- even the more extreme purists re individual selection and the selfish gene, do acknowledge that evolutionary selection can , if only sometimes and at relatively weak frequencies , work at the level of group survival, especially if the groups are closely genetically related.

          If the trait for ‘ exclusively gay’ (and I am definitely not saying there is such a thing, at all) is pretty recessive and it, in less than fully expressed forms gives some sort of advantage , in at least some environments, it will be retained , not selected against .

        • conrad says:

          John, I’m just trying to say that there are evolutionary psychology theories of almost everything, almost none of them testable. I personally doubt there are any “gay genes” directly related to sexuality. But for every phenomena in psychology, there’s always someone willing to give an evolutionary perspective.

          If you want another example where we don’t need to argue over possible claims since they’ve already been made, then people’s preferences for symmetrical faces is a good one. This effect was found about 25 years, is pretty robust (you always find it and it works cross-culturally), and the main evolutionary story was that being symmetrical is a sign of good health, and people like to select partners that are healthy, and so we find symmetrical faces more attractive. People believed this story for about 2 decades. But Jill Rhodes over at UWA finally went and really tested it by digging up people’s health records. She found that there’s actually no evidence that being unhealthy makes your face less symmetric. So self-confirmation bias would have won again (it did for 2 decades), except in this case it was actually testable. And this was for something pretty simple, let alone something complex (c.f., e.g., intelligence).

          These types of things are why I wouldn’t ever put too much faith in any evolutionary psychology theory of almost anything to do with complex thought.

        • john Walker says:

          In hindsight I was guilty of talking at cross proposes , please acept my apologies .

  10. Julie Thomas says:

    There are some interesting evo psych ‘narratives’ about intelligence as a multi-faceted construct.

    One idea is that it was the need to understand “the emotional content of human relationships” that “precedes and lends structure to human cognition, ultimately even to the most abstract forms.”

    Sarah Blaffer Hrdy argues that our capacities for strategic social behaviour and emotional regulation were the drivers of cognitive growth. She focuses on women and children – and the altruism that this relationship requires – as the catalysts for the changes that took us from primates to human.

    “She allows that fathers do contribute to infant and child caretaking, but only to a
    limited degree and in a facultative fashion, ultimately due to the fact that their own reproductive success is not tightly enough constrained by that of their partners. Fathers can help, but not enough to drive the evolutionary change that occurred, in Hrdy’s opinion.”

    She thinks the assumption of primitive patrilocality is wrong and stresses “the importance of matrilineal kin in supporting especially new mothers among extant human groups. Hrdy reviews and accepts the evidence for grandmaternal contributions championed by Kristen Hawkes and her colleagues, but notes that a broader web of matrilineal kin and even non-kin can also be important. “If long-lived grandmothers were humankind’s ace in the whole, all these classificatory kin—distant relatives, godparents, possible fathers, namesakes, trading partners, and other manufactured alloparents—became their wild cards”

    And gay relatives would be part of this kin system for raising children.

    Hrdy also thinks “that human evolution never stops, and points out that the loss of our formative “conditions of rearing,” the dissipation of webs of shared care and domestic cooperation, could undermine the very conditions that have made us human.”

    from a review of her latest book

    Rob Brooks who writes evo psych stuff for The Conversation mentioned Sarah Blaffer Hrdy in an article but did not provide any discussion of her work.

  11. paul frijters says:

    Last Friday, Peter Visser gave a talk at our school of economics at UQ. He publishes regularly in Nature and Science with this behavioural genetics stuff. He first worked on cattle before moving on to humans.

    • conrad says:

      I have seen another one of UQs good genetics guys about two years back (David Evans) and he gave a very good and realistic talk (well worth seeing). He gave a good example where he noted that twin research suggests 40-80% of the variation in human height and simple morphology is heritable (i.e., how broad/thin you are — which is something really easy to measure and concrete in nature), but modern genetic analysis can only “explain” (correlates with) 2-3%. Extrapolating that to complex behavior suggests lots of difficulty ahead, and that your article is probably spot on.

    • john Walker says:

      Paul could you give a link to the talk or relevant paper?

      • paul frijters says:

        He was giving a medley of about 10 published papers, usually in Nature. Since he was talking about some forthcoming stuff, I believe his slides are not available.

        • conrad says:

          “The estimated effects of all lead SNPs associated with depressive symptoms and neuroticism were in the range of 0.020–0.031 s.d. per allele (R2 ? 0.02–0.04%)”…”According to our Bayesian calculations, the true explanatory power (corrected for winner’s curse) of the SNP with the largest posterior R2 is 0.003% for subjective well-being, 0.002% for depressive symptoms, and 0.011% for neuroticism”

          And this is with no theory as to what is explained in the variance (e.g., for all I know, it could be something entirely unrelated: affects assimilation of alcohol and alcohol correlates with depressive symptoms). Here is a Darwin quote which explains what I think about this:

          “About 30 years ago there was much talk that geologists ought only to observe and not theorise; and I well remember someone saying that at this rate a man might as well go into a gravel pit and count the pebbles and describe the colours. How odd it is that anyone should not see that all observation must be for or against some view if it is to be of any service!”

        • John walker says:

          Conrad its a lovely quote. One of our favs.

          I think that the papers abstract implies that they ‘intuit’ that loci that regulate rates of expression ( of other gene groups or …?) in the nervous system and in the adrenal system etc have a role in depression etc.
          Or am I wrong?

        • conrad says:

          Hi John,

          they are basically saying some of the genes involved tend to be correlated with other studies that have looked at particular behaviors that are related to certain parts of the bodies. Perhaps the genes related to the pancreas one are for having a good shit (and henceforth wellbeing). If you are interested, I have stuck a copy of the paper in my dropbox.

        • john Walker says:

          Conrad thanks
          So it’s just the cutting edge of conformity?

  12. conrad says:

    It’s a new area, and they are finally getting data sets where the sample is big enough such that you can do some types of analyses never possible before (100K people+), so it is not surprising that it gets a lot attention as people want simple biological answers for everything. So if you explain 1% of the variance, somehow this a big deal if you do it with genes versus any other marker. One upside is that the genetic level can be thought of as some sort of atomistic level where everything starts, so there is some appeal to it (in the same way as neurons are the bases of the brain — of course, if you tried to build a theory of any complex thing based on neurons and nothing in between, you get nowhere, but, apart from a few crazy Europeans and their big brain project which is doomed to fail, more or less everyone accepts this).

    I think the problem at present is the type of analyses used, which is basically just one set massive set of correlations, and if you are going do massive amounts of correlations, you need to be very careful about what you select as causation. So you end up with a small pile of possible genes. There is also no bottom-up theory (which the guy I saw talking suggested was an advantage), so it really is like trying to explain the tide with grains of sand. Lately, they have been putting in interaction terms between genes to try and pick up more variance, but the same problem remains. Unless there is some solution to this, it will be a taxonomy that predicts small amounts of variance and doesn’t shed any light on most problems.

    I remember being excited when I first saw genetic analysis in my area, and the first few genes that correlated with actual behavior. I initially thought I should get into that area (one of my friends had contacts that were doing it). After a decade an a half, there are now hundreds of possible genes, none of which has led to any meaningful understanding of the problem and none of which can be used for any clinical purpose. This is no surprise, because even a simple task like reading requires many things — visual processes looking at the letters, language processes, etc. . So lots of work led nowhere apart form finding lots of correlations. As a comparison, you can pick up more predictive variance by doing a 10 minute test on 2 year olds with a simple electode.

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