> As Plomin writes: “We now know that DNA differences are the major systematic source of psychological differences between us. Environmental effects are important but what we have learned in recent years is that they are mostly random – unsystematic and unstable – which means that we cannot do much about them.”
I'm not sure what to read in the implied statement that we can do something about genes
Can you give a source for that? I remember reading something contradicting this statement and my own research into possible myopia causes seems to indicate environmental factors as the cause (but not conclusively).
As a myopic person that has no one in my extended family suffering from it, I am very confused as to the possible causes.
> I'm not sure what to read in the implied statement that we can do something about genes
Gene therapies are a known quantity, as is genetic awareness (in mating). It is evident that, at least generationally, something ethically-sound an be done to change our genetic character.
Of course, some people's minds will shift immediately to eugenic killing and sterilization, but I'm not sure why anyone would get the impression that the Guardian is (currently at least, though they do have an authoritarian bent at times so who knows) much for those things.
I, for one, want to see the day when we edit out the "recurrent" nature of the recurrent laryngeal nerve.
I would be very happy if such scientific inquiries were freed from the depredations of the culture war, and our culture accepted the nuanced and moderate truth: both nature and nurture play a role.
Genes can be activated by the environment, as early as the womb. So in the case of the twins, a brief shortage of nutrients or oversupply of nutrients, may cause certain genes to not active, active late, activate differently, etc.
From what I gathered on the studies around it all, most of the outset is defined by genes, the environment then can play on the existing genes. Ie, if you don't have the genes to be smart, you won't be smart and there isn't much you can do about it past a certain point, if you do have them, you can be smart or you can still be dumb without being able to do anything about it. Or height. If you have genes to be 2m tall it won't help you much if a nutrient deficiency in early childhood stunts growth and leaves you at 1.6m.
So in the case of the identical twins, they likely have both a potential to develop autism or at least tendencies towards the spectrum but only in one the specific genes activated for whatever reason.
The split is really 3 ways, nature/nurture/noise, although the latter two tend to get lumped together and called nurture.
The rule of thumb for most complex traits is half genetic, half environment... but this half is almost all "un-shared environment", meaning things specific to the individual (possibly random), not "shared environment" meaning observable things like parents, diet, schools, typically shared between siblings.
I don't know the numbers for autism, but would guess it's like this. Which is to say, be careful how you read statements that nurture plays a role -- it's often written to mean "not-nature", and but read to mean "upbringing".
The obvious pull quote, already in this thread, seems to say that this is a case of looking where we have the tools to look rather than where it makes a difference. Because you can get DNA with a swab and a MiSeq, you should try to determine the causes there rather than do the hard work of determining confounding environmental factors.
The end argument works out to laziness if the goal is to determine causes. If the goal is engineering change, the article makes it's own countercase - improvements to society-wide resources make for society-wide changes in behavior.
The end argument works out to laziness if the goal is to determine causes.
If your argument is that it must be so for reasons of ideological aesthetics, then you're in the company of Lysenko.
If the goal is engineering change, the article makes it's own countercase - improvements to society-wide resources make for society-wide changes in behavior.
If the culture would broadly accept that both nature and nurture contribute something, we'd be much better able to deal with a ground truth which is complex and nuanced.
Biology is one of those areas where ground truth tends to be complex and nuanced. Psychology is another field like this. The practice of good governance is yet another.
It would help if would-be popularizers of the "nature" factor could get basic concepts straight, like (in Plomin's case) the difference between correlation and causation, or (in Plomin's pop-sci advocates' case) the meaning of "heritability".
These are general problems in the interpretation of science, and their presence isn't exclusive to the political left or right. (The one exception I can make out being Climate Change.)
It shouldn't be a debate. It should be a "knob" we're tuning in. In general, the Left has had an ideological stake in "nurture." Various progressive utopian visions had such an ideological stake, communism being the most obvious one. Intersectionality and Feminism have taken up the nurture baton, as they have an ideological stake in forwarding nurture and denying any significant role for nature.
Again, in a field like biology, many of the answers are going to be complex and nuanced. Black and white binaries mandated by ideology are not going to be the likeliest answers.
It... clearly is a debate? Like, a fundamental and unanswered question spanning many scientific fields? That’s interesting to me. The political valences you choose to assign to each side of the debate: not so much.
In as much as Climate Change is a debate. Which is to say, it isn't, except for ideological wishful thinking. It's settled science that both nature and nurture are involved in human behavior to some extent. It's only a question as to how much, with a lot of noise generated in popular accounts motivated by ideology.
The political valences you choose to assign to each side of the debate: not so much.
Skewing of politics to the left or right in a given field can cause systemic bias. Both conservative and more open voices need to be heard to avoid groupthink causing the social environments within each field from going off the rails.
You and I have already had discussions about how fields can engage in such behaviors to produce artificial exclusivity and act in ways contrary to facts and their own and society's self interests.
I think you're pretty much begging the question now, aren't you? "There's no debate except HOW MUCH genes influence behavior". Well, we pretty much all agree that Downs Syndrome exists, so I think we knew going into this thread that there was some genetic component.
Well, we pretty much all agree that Downs Syndrome exists, so I think we knew going into this thread that there was some genetic component.
It's not begging the question, if you're going to concede the point that it's not a question of if, but how much. Are you also in denial of genetic, epigenetic, and in-utero biological factors affecting behavior in large mammals and highly intelligent animals? I should hope not. Are you in denial of biological factors affecting social organization behaviors in such animals? Are you asking for a special exception to all the above for Homo sapiens for reasons of ideology? In that case, I'm not the one begging the question here.
I'm just not interested in your politics, sorry.
If you're politicizing science, then you are interested in such politics. So is your position now that the effect is nonzero, but it can't be much larger because of ideological/aesthetic reasons?
What I'm asking for is less politicization of science. Science has gotten politicized in the US and much of the west, to the point where people can be un-personed for wrongthink. Ideas should be tested and bad ideas should be debunked. Suppressing words and ideas for the sake of feelings is the real danger. Incitement and other real harms are ultimately fueled by strong feelings combined with de-personalization, not by cold rationality.
Why I don't find many of these types of articles interesting isn't because of the supposedly provocative genetic part, but of the glossed over results. They look at something like grades and then try to find a link between those grades and genetics. Eventually they do and conclude that there is a link between genetics and grades. But they don't consider if those genetics or grades are important in themselves. Which is why these sort of studies tends to not survive real comparisons e.g. between groups with different norms.
Even so I think the largest flaw tend to be in the final conclusion. Which is essentially always about how we should treat less fortune people. They day such an article conclude that we need to shut down private schools and make sure we don't have genetically challanged CEOs I will give them points for being provocative.
AFAIK, the consequences of DNA depend as much or more on the processing of them by RNA and otherwise than on the original genes. I wonder how the theory accounts for that (I'm not pointing out flaw as an armchair cynic, but asking a question.)
Also, obviously environment plays a major role in our lives and I'm certain Plomin would agree: Abusive parents (or no parents), childhood experiences (think of rape survivors), education, the opportunities around us, access to resources, etc. etc. I would guess he's talking about an essential psychological nature that may determine how we respond to those things. My question is, where does he draw the line between that 'essential nature' (accepting for sake of argument that it exists) and environmental influence?
EDIT: "Plomin’s argument is that, in a society with universal education, the greatest part of the variation in learning abilities is accounted for by genetics, not home environment or quality of school– these factors, he says, do have an effect but it’s much smaller than is popularly believed."
Calling it "universal education" (the Guardian's paraphrase, not necessarily Plomin's words) is a big stretch - it's so different in different places, including in the same country, that it doesn't all fit under one term. Without more specific claims, it's hard to address that quote but I was reading in the last year about one poor school district which had accomplished a milestone: Half the third graders could read. Half those kids are in deep trouble, and I don't think that's due to genetics.
Re processing of DNA etc, this isn't the level these studies are typically working at. There's no biochemistry knowledge involved. They are just looking at DNA sequences, and what data they have about outcomes. Whether a piece of DNA makes something critical for some muscle, or is 10 steps away in part of some complicated switching apparatus, of indeed just influences something else which causes the growing animal to enjoy behaviour which happen to exercise this muscle -- all of this detail is a black box, all of these would contribute to genetic effect.
Re universal education, etc: in adoption studies this translates to "among parents who will be approved to adopt", and this indeed cuts the very bottom off the distribution of some factors. I don't think it's a huge issue, but not an expert.
But my understanding of the point Plomin is making there is a bit different. Regardless of the current state of (say) schooling, he's pointing out that moving from a system with large schooling inequalities, to a system of absolute schooling equality, would almost certainly increase the heritability of education. In the unequal system, some bright kids are stunted etc, weakening the correlation between input and output; but in the equal one, all the variation in the output will be driven by the input.
At least I think that's what he's saying. Haven't read the book, and not really my field at all...
Whoa, this is encouraging. A thoughtfully-written piece on an extremely important (and, lamentably, controversial) subject devoid of hyperbole and rancorous partisanship.
... published by The Guardian, no less. I am shocked and very pleased.
Another problem that Plomin encounters with explaining his findings is that people often confuse group and individual differences – or, to put it another way, the distinction between means and variances. Thus, the average height of northern European males has increased by more than 15cm in the past two centuries. That is obviously due to changes in environment. However, the variation in height between northern European males is down to genetics. The same applies to psychological traits.
“The causes of average differences,” he says, “aren’t necessarily related to causes of individual differences. So that’s why you can say heritability can be very high for a trait, but the average differences between groups – ethnic groups, gender – could be entirely environmental; for example, as a result of discrimination. The confusion between means and variances is a fundamental misunderstanding.”
How does this work? How can one thing that causes the motion of the average not also affect the variation? How wouldn't the one which inherited the worst genes not benefit from environment?
It is like how rising tides lift all boats. A good environment helps people without the right genetics; but this does not mean that this group can beat another set with right genetics in the same good environment.
What you just said sounds like a misunderstanding of the words "average" and "variance". Usually when things like intelligence is modeled, it is modeled as a normal distribution. Moving the average for a normal distribution moves the majority of people in the distribution. Variance just expresses how wide the distribution is, or how far you can expect people to deviate from the average.
What you're saying seems to suggest the distribution is multimodal. I'm not sure that's what they said.
> A good environment helps people without the right genetics; but this does not mean that this group can beat another set with right genetics in the same good environment.
I think that's backwards from what Plomin is saying in that quote. He's saying that, regardless of genetics, a better environment will cause the average performance of the group experiencing it to outperform the average performance of a group experiencing a worse environment. And he's saying that DNA influences the amount of each group's variation around that average performance. For example, if we were looking at height,
* There are two groups, 1 and 2; people in Group 1 have one kind of tallness DNA (tDNA, something I just made up), and people in Group 2 have another kind of tDNA; also, Group 1 grows up in an environment with better nutrition and exercise than Group 2. Both groups are one gender, let's say women, to simplify height statistics.
* Group 1 averages a height of 5'7" due to their relatively better environment, and due to their tDNA their variance is that 50% are between 5'5" and 5'8", a 3-inch range, and 95% are between 5'3" and 5'10", a 7-inch range.
* Group 2 averages a height of 5'5" due to their relatively worse environment, and due to their different tDNA their variance is larger: 50% score between 5'3" and 5'9", a 6-inch range, and 95% are between 5'0" and 5'11", an 11-inch range.
Actually I couldn't understand this concept, seems to me he is just afraid of the implications of his theory. If anything I would think that the multiplication of the genetic effect creates much larger differences between groups than between individuals.
It is similiar to sport, people like to watch one on one female sport like tennis or various olympic sports because the effect of them being slightly worst than men doesn't manifest that much. But once you look at team sports like football or basketball it just multiplies and it looks so much worst than the men equivalent.
Not sure why this is so hard to accept, why would evolution stop at the neck? Nobody has a problem with saying height is mostly genetic, yet say the same of intelligence and it's controversial.
And yet until the industrial revolution, environmental factors were the dominant effect. Anyone could have been taller with enough nutrition.
Genes are only ever expressed under certain environmntal conditions. The minimal condition for all of them is being alive. Malnourishment, or perhaps too much caffeine, amongst a hundred other things, all determine how our genes for height express themselves.
Which is all to say, people are wrong when they say height is mostly genetic. It may be true enough under current social conditions though. I think the same problem applies to calling intelligence "largely" genetic.
"when they say height is mostly genetic ... under current social conditions"
This is always what's meant. Perhaps it should be said more often... but nobody doubts that we can grow a bonsai.
The interesting question is how much do different factors matter in our present environment (and again ideally one should specify, e.g. rich-country & above-poverty-line, not just 201X) and in environments we might reasonably hope to create.
People often say body or mind, but really it's all "body" . Not everyone has the same arm and leg strength, so why should each brain be the same.
Reflex for instance, if u do an action long enough, it has been shown that a reflex curve grows in the brain, basically a "GOTO" in programming, which is a direct path. This directly increases performance, as can be seen in any sport, videogame or instrumentalist (music) This is "as muscle" as something can be.
There's an overemphasis on the cognitive/sensory part of the brain, which i take hindrance in, especially with AI development.
Motivation, Gut feeling, instinct, focus, excitement, persistence, self-motivation, annoyance, inspiration. I can list 100's of things, which hasn't even seen a single notion of being synthesized in AI, yet all these things, often not even aware, make us do what we do, and it's totally unknown how much of a factor they are in the grand scheme of our intelligence, and the ability to create/come to solutions by our own sentience.
imagine we synthesis fear in machines. Fear is what often keep us motivated. Closely tied to loss, losing people in a natural distaster creates incentive to fix/prevent. However, this only logically applies if empathy is present. Without empathy, no incentive to fix some other's bullshit. I don't get why these things are so grossly overlooked in our way to create more sentient machines. It's all so tied together in the simplest of human actions, that leaving it out seems a very un-scientific thing to do. Evolution of the human is it's own prove on how well such a system can work when it relies both on cognition as well as emotion.
Our mind only describes "how" we do what we do, but not "why" we do what we do.
The controversy isn't about whether differences exist or not, but rather how strong those differences are, and how much we should factor them into society.
When people try to be positive by saying: "it's not all natural talent, you must also work hard and persevere!", I wonder, aren't those also shaped by our genes? Is the ability to work hard and the mental fortitude not to give up not also something dictated by our genetics?
You can take that one step further. Couldn’t the willingness to believe in the foreordaining nature of genetics also be determined by genetics? Maybe those people, who believe that genetics does not determine everything, cannot believe otherwise, because of their own genes? In that case, isn’t there no point in you trying to argue about this? Those who believe in genetics and determinism will do so and leave everything to fall as it may, and those who believe in personal hard work and perseverence will try to work as hard as they can, because that is their nature.
To fully generalize the concept, take Samuel Butler's formulation from Erewhon: If it were possible to know everything about the past, it would be possible to know everything about the future.
Zoom out far enough and nature and nurture are unified into a deterministic historical timeline. Freewill is an illusion and the universe is a static four-dimensional entity.
Doesn’t quantum mechanics leave open the possibility that our universe is fundamentally probabilistic?
Also, how can we say anything about free will when we have not come to grips with defining the hard problem? Of course, if you want to model biological processes based on deterministic physics then free will does not exist. I’m simply suggesting that the fundamental assumption that are universe is deterministic is flawed.
> Doesn’t quantum mechanics leave open the possibility that our universe is fundamentally probabilistic?
Not really. A wave function propogates in a perfectly deterministic manner. There's not anything probabilistic baked into QM.
Probability comes in at what's called the Measurement Problem. Right now, we ad hoc apply the Born rule to project complex amplitudes into probability distributions whenever convenient, but there's actually no good understanding of why the Born rule works at all. It's just sorta tacked onto QM at this point.
It really doesn’t matter if the laws of nature are deterministic or not. Consider the past. At no time did a die come up both two and five, nor did a photon’s wavelength collapse in two places. Why should the future be considered differently? Events in the future will happen one specific certain way – we just can’t know which way until they actually happen. But we don’t have to be able to (even theoretically) predict future events for those future events to still be fixed in a four-dimensional space-time.
This is my lazy excuse for not being an overachiever. I see people at the top of their fields and they so obviously seem innately driven to perform and be amazing. I was not born with that instinct and my brain doesn't reward me the same way theirs does. I'm fine with this.
My comment is less focused on the cause and more about accepting the result. I have no strong opinion on nature vs nurture but regardless my genes and upbringing have led me to accept I'm not that type of person
I agree completely as I come to terms with my self. With much humility, I have enormous potential but it is tempered by a lack of that drive to fullfil it. My path has been largely driven by chance and yet I am in some ways way beyond average. I'd rather work on my percieved shortcomings than make use of my advantages. I should probably change my priorities. \drunkpost
You could also be "fated" to begin achieving the things you want tomorrow. The universe being deterministic doesn't mean that you personally know your own future. Our predictions for ourselves are likely to be wrong in many ways. We can't know until we try.
It's a balance to both accept reality as it is while also striving to achieve things that we didn't know for sure were possible (or that we hadn't even conceived of yet!).
It seems that we must carefully straddle the boundary between the known and the unknown. Of course, this will look different for everyone.
I focus on gaining meaning and happiness in life from things other than achievement. The things I do mean less to me than the experiences and relationships I have in life. I don't need a $100 million yacht and a Wikipedia page to love the people around me and feel loved in return. I think what I have is a lot more valuable.
> "it's not all natural talent, you must also work hard and persevere!"
I understood this to mean that to achieve your full potential ( naturally given potential ), you have to work hard and persevere.
A kenyan long distance runner might have a natural potential far greater than everyone else, but he still has to train to reach his natural potential.
> Is the ability to work hard and the mental fortitude not to give up not also something dictated by our genetics?
Genetics may predispose you to working harder and being mentally strong, but that's something you can change through hard work. You can't grow to be 7'5" like yao ming by working hard. You can't run as fast usain bolt by working hard. There are natural/genetic/physical limits. And there are natural predispositions.
I'm not a geneticist or a biologist so take it with a grain of salt.
I've observed for quite some time that determination, charisma, and the ability to sustain focus are more significant than either natural ability or education. If you don't believe me spend some time in New York.
It's something that came up a while back in a discussion with a friend on the concept of AI super intelligence. I personally don't think you would need superhuman IQ to run circles around humans. Superhuman focus and drive would do it. Something with a 150 IQ but able to operate like a person on amphetamine but minus the side effects and enter sustained periods of "flow state" focus at will would be godlike. Hell even mediocre IQ with superhuman focus would be scary.
If you want a very good summary of recent genetics research results, have a look at Adam Rutherford's A Brief History of Everyone Who Ever Lived: The Stories in Our Genes. Basically, even the most careful and underwhelming claims from the popular press overstate how much we actually understand about the connection between genes and real world attributes of people.
Anecdotally, anyone who has ever recontacted an adopted-out sibling will be able to tell you how much this is true.
We got back into contact with my older sister who had been adopted when I was about 12. She's absolutely the spitting image of her parents, both in looks and behavior, despite being raised in about as different a household as is possible.
Regarding socio-economic status:
I have more than 2 university degrees. My dad attained the lowest higher educational attainment there is. My mom did not even finish high school. My mom and dad have all kinds of addiction issues regarding alcohol and drugs. I don't. I have more patience than both of them and am more level-headed. And I'm also pretty sure I'd be a better parent than them, since they set such a low bar that I had to be adopted and raised by my grandparents after 1 year.
Sometimes I wonder how I am a product of both my mom and my dad, because there are quite a bit of things in which I don't recognize myself in. If it was all nature, then it'd have been easier to spot and I'd also be addicted to a lot more things.
My upbringing was similar with regards to my mom (same people). But the situation was different, my grandpa didn't work much when I was around but was a workaholic during my moms time. My dad was beaten as a kid. I wasn't.
If it really is al genetics then how do you explain such a difference in socio-economic status? I think for them it's part drug abuse, a fucked up childhood and no nudge to do your best at school (in my dad's case, I don't know about my mom). I know that my dad had a propensity for learning but he never got to utilize it.
I'm pretty sure that if my dad had been in a better upbringing that he'd have fared better. I'm also pretty sure that if my momd would've been born around 1995 that she'd have fared better.
One interesting thing about genetics, and a very conspicuous one, is that randomness plays a not so little part in the process. Otherwise you wouldn’t even have evolution. How could a species adapt to a changing environment if heritability was the only determining factor?
In that case, it could be justified to think of you as one of those wildcards that nature continuously throws into the mix to sharpen the species adaptability.
That is, if you spread your genes around and those also prove more adapted. And so on.
It's not controversial that the large intelligence differences between cats, dogs and chimpanzees are genetic. Nobody says that in the right environment and nurture a cat will become as smart as a chimpanzee.
But somehow it's very controversial that the small intelligence differences between humans might be genetic, as if a species has a fixed IQ number, and the only IQ jumps are strictly between species, but not between individuals.
That depends on what you mean. If you mean "there is a genetic component to intelligence", that is not controversial. If you mean "there are intrinsic differences in the genetic backgrounds of particular races that lead to differences in intellectual ability", that is extraordinarily controversial.
I'm not quite sure what you're asking here. I feel that you and I must have drastically different starting assumptions, because your question seems meaningless in my context.
Do you dispute that Homo sapiens has a higher intelligence than H. erectus did? Than other primates?
Or are you alleging that the genetic basis for that intelligence difference shows no variation across human populations?
I feel like I have to stretch what you said to give it a charitable interpretation, but here goes: are you asking whether there's any evidence that the genetic component's variation across human populations contributes to significant phenotypic variation when compared to environmental factors?
It isn't particularly controversial that IQ has a genetic component. What is controversial are other conclusions derived from that. Saying that something is controversial is often used as a rhetorical device to add credibility to arguments that aren't conclusive.
It's exactly this. It's easy to say that genetic differences account for differences in IQ among human beings.
The flaw is when you start to extrapolate that to things like racial issues. Saying that for example black people are less intelligent due to their genetics would ignore a lot of environmental circumstances that can lead to people not achieving their full potential. There's also the conclusion that if someone is born from a poor and dumb family that therefore their genetics must be worse and so forth.
Framing the argument as 'nature not nuture' would still ignore that if you had two people with identical genes born into a rich family vs a poor family that their theoretical 'genetic potential' is going to be highly limited by their environment. The genetic argument quickly becomes a tool with which to justify hurting others.
> if someone is born from a poor and dumb family that therefore their genetics must be worse and so forth.
That particular assumption would be false because of genetic crossover. Two mentally disabled people could give birth to a genius child if recombination results in an offspring not carrying or expressing whatever causes their disability. The probability of this happening is higher if the pair is less closely related. The inverse can also happen of course, and does.
This is really why sexual reproduction seems to exist. It's also why the racial purity crowd has it precisely wrong. One hypothesis on the Flynn Effect is that it could result from increased outbreeding due to modern levels of travel and migration.
On its face this study doesn’t seem controversial, but it’s easy to see how people can find confirmations of their own biases in it. For example when discussing race and gender.
Biological determinism flatters the current elite -- "You're on top because you're inherently superior!" -- so it will always find an eager audience regardless of whether it is true. All the excess cheerleading makes it incredibly hard to assess.
I would have thought the exact opposite. Wouldn't the current elite rather believe that they are on top because they worked hard and earned their place? That way they can look down on the rest in good conscience while gutting welfare systems that only benefit those who "didn't" earn their own way.
Arguments that the successful are morally superior will also find an eager audience. In contrast, arguments that successful are inherently inferior in any way are a hard sell.
The article mentions that much of this research is based on twin studies. I have a question about how these studies work - perhaps someone here has done this sort of research and can answer.
Here's my understanding of twin studies: you have some identical and fraternal twins. Each pair of twins are raised in the same household, and presumably experience the same environmental "nurture" effects. So, if we see stronger intellectual similarities between identical twins than fraternal twins, then we conclude that this difference is genetic.
But how valid is the assumption that the environments that fraternal twins face are as similar as those of identical twins? Let's assume for instance that:
1) women and men have the same innate potential for mathematical skill
2) our education system does a better job fostering mathematical ability in men than women
3) over time, this discrepancy causes women to score lower on tests of mathematical skill than men
While our identical twin pairs will all be of the same gender, the fraternal twin pairs may not. Two identical twin boys might receive the same environmental effects on their mathematical ability, but a girl and her twin brother will not, even if they have equal mathematical potential.
Given these assumptions, if we conducted a twin study on mathematical ability, we would see a stronger correlation between the scores of identical twins than those of fraternal twins, due to gender difference, and we would conclude that mathematical ability has a genetic component.
And our conclusion wouldn't be wrong! If gender impacts mathematical ability, and gender is genetic, then mathematical ability does arguably have a genetic component. But this gender difference comes about not because of an innate intellectual difference between women and men, but because of how a child's environment "nurture" changes depending on an arbitrary genetic trait "nature". In a world where these assumptions are true, a child's genes influence their future mathematical abilities - but in another world without gender-based educational discrepancies, the same genetic difference might not have any effect.
How do twin studies account for these more nuanced situations, where society causes nature and nurture to coincide in roundabout ways? Does it make sense to simply call these "second-order" socio-genetic effects "nature"?
The best twin studies look at pairs of identical twins who were separated at birth and raised in different households. If they still end up more similar to each other than to their adopted siblings on some trait, we conclude that trait has a significant genetic component, and more sophisticated analysis can measure how significant it is. Note that the technique I described is not strictly able to determine whether the effect is from genetics or some other pre-birth shared environment, like maternal alcohol consumption. For many practical purposes, that distinction doesn't really matter.
Human performance depends on a number of factors. These factors form a chain and this chain is as strong as its weakest link. So yes, some genetic diseases are severe enough to undermine cognitive performance. But no, genes are not the weakest link for most people. We are still wasting most of the human potential we already have. There is no need to seek genetic improvements at this stage.
I don't like the way he seems to connect the science to the political spectrum. I think it would be the thinking of the left that we need to improve the environment especially for the disadvantaged (including those disadvantaged for genetic reasons) in order to improve society as a whole. Then he mentions how it was "dangerous" to publish his research, feeding the victim complex of those whose thinking doesn't line up with what he considers to be the left apparantly. Whoever claims that raw, uncivilized human nature bolsters equality can't be thinking straight.
I think it was a good point, that we have come a long way to equalizing the environment and that leaves a big part of the differences to genetics. I would say that is very high praise to the achievements we already made and shows that we are on the right way. I would guess that the same study made in a more unequal society would have different results.
Plomin's central argument seems to be that once you control for environment, genetics explains the remaining differences:
"Plomin’s argument is that, in a society with universal education, the greatest part of the variation in learning abilities is accounted for by genetics...
...Thus, the average height of northern European males has increased by more than 15cm in the past two centuries. That is obviously due to changes in environment. However, the variation in height between northern European males is down to genetics"
To conclude that it is "nature not nurture after all" based on this argument, seems quite backwards.
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[ 4.5 ms ] story [ 171 ms ] threadI'm not sure what to read in the implied statement that we can do something about genes
Genetic cause does not imply genetic cure.
https://www.aao.org/editors-choice/sunlight-exposure-reduces...
As a myopic person that has no one in my extended family suffering from it, I am very confused as to the possible causes.
Gene therapies are a known quantity, as is genetic awareness (in mating). It is evident that, at least generationally, something ethically-sound an be done to change our genetic character.
Of course, some people's minds will shift immediately to eugenic killing and sterilization, but I'm not sure why anyone would get the impression that the Guardian is (currently at least, though they do have an authoritarian bent at times so who knows) much for those things.
I, for one, want to see the day when we edit out the "recurrent" nature of the recurrent laryngeal nerve.
So those of us who strive to do better than the lizard brain should be taking up the nuanced, moderate view.
Genes can be activated by the environment, as early as the womb. So in the case of the twins, a brief shortage of nutrients or oversupply of nutrients, may cause certain genes to not active, active late, activate differently, etc.
From what I gathered on the studies around it all, most of the outset is defined by genes, the environment then can play on the existing genes. Ie, if you don't have the genes to be smart, you won't be smart and there isn't much you can do about it past a certain point, if you do have them, you can be smart or you can still be dumb without being able to do anything about it. Or height. If you have genes to be 2m tall it won't help you much if a nutrient deficiency in early childhood stunts growth and leaves you at 1.6m.
So in the case of the identical twins, they likely have both a potential to develop autism or at least tendencies towards the spectrum but only in one the specific genes activated for whatever reason.
The rule of thumb for most complex traits is half genetic, half environment... but this half is almost all "un-shared environment", meaning things specific to the individual (possibly random), not "shared environment" meaning observable things like parents, diet, schools, typically shared between siblings.
I don't know the numbers for autism, but would guess it's like this. Which is to say, be careful how you read statements that nurture plays a role -- it's often written to mean "not-nature", and but read to mean "upbringing".
The end argument works out to laziness if the goal is to determine causes. If the goal is engineering change, the article makes it's own countercase - improvements to society-wide resources make for society-wide changes in behavior.
If your argument is that it must be so for reasons of ideological aesthetics, then you're in the company of Lysenko.
If the goal is engineering change, the article makes it's own countercase - improvements to society-wide resources make for society-wide changes in behavior.
If the culture would broadly accept that both nature and nurture contribute something, we'd be much better able to deal with a ground truth which is complex and nuanced.
Biology is one of those areas where ground truth tends to be complex and nuanced. Psychology is another field like this. The practice of good governance is yet another.
Again, in a field like biology, many of the answers are going to be complex and nuanced. Black and white binaries mandated by ideology are not going to be the likeliest answers.
In as much as Climate Change is a debate. Which is to say, it isn't, except for ideological wishful thinking. It's settled science that both nature and nurture are involved in human behavior to some extent. It's only a question as to how much, with a lot of noise generated in popular accounts motivated by ideology.
The political valences you choose to assign to each side of the debate: not so much.
Skewing of politics to the left or right in a given field can cause systemic bias. Both conservative and more open voices need to be heard to avoid groupthink causing the social environments within each field from going off the rails.
You and I have already had discussions about how fields can engage in such behaviors to produce artificial exclusivity and act in ways contrary to facts and their own and society's self interests.
I'm just not interested in your politics, sorry.
It's not begging the question, if you're going to concede the point that it's not a question of if, but how much. Are you also in denial of genetic, epigenetic, and in-utero biological factors affecting behavior in large mammals and highly intelligent animals? I should hope not. Are you in denial of biological factors affecting social organization behaviors in such animals? Are you asking for a special exception to all the above for Homo sapiens for reasons of ideology? In that case, I'm not the one begging the question here.
I'm just not interested in your politics, sorry.
If you're politicizing science, then you are interested in such politics. So is your position now that the effect is nonzero, but it can't be much larger because of ideological/aesthetic reasons?
What I'm asking for is less politicization of science. Science has gotten politicized in the US and much of the west, to the point where people can be un-personed for wrongthink. Ideas should be tested and bad ideas should be debunked. Suppressing words and ideas for the sake of feelings is the real danger. Incitement and other real harms are ultimately fueled by strong feelings combined with de-personalization, not by cold rationality.
Even so I think the largest flaw tend to be in the final conclusion. Which is essentially always about how we should treat less fortune people. They day such an article conclude that we need to shut down private schools and make sure we don't have genetically challanged CEOs I will give them points for being provocative.
Also, obviously environment plays a major role in our lives and I'm certain Plomin would agree: Abusive parents (or no parents), childhood experiences (think of rape survivors), education, the opportunities around us, access to resources, etc. etc. I would guess he's talking about an essential psychological nature that may determine how we respond to those things. My question is, where does he draw the line between that 'essential nature' (accepting for sake of argument that it exists) and environmental influence?
EDIT: "Plomin’s argument is that, in a society with universal education, the greatest part of the variation in learning abilities is accounted for by genetics, not home environment or quality of school– these factors, he says, do have an effect but it’s much smaller than is popularly believed."
Calling it "universal education" (the Guardian's paraphrase, not necessarily Plomin's words) is a big stretch - it's so different in different places, including in the same country, that it doesn't all fit under one term. Without more specific claims, it's hard to address that quote but I was reading in the last year about one poor school district which had accomplished a milestone: Half the third graders could read. Half those kids are in deep trouble, and I don't think that's due to genetics.
Re universal education, etc: in adoption studies this translates to "among parents who will be approved to adopt", and this indeed cuts the very bottom off the distribution of some factors. I don't think it's a huge issue, but not an expert.
But my understanding of the point Plomin is making there is a bit different. Regardless of the current state of (say) schooling, he's pointing out that moving from a system with large schooling inequalities, to a system of absolute schooling equality, would almost certainly increase the heritability of education. In the unequal system, some bright kids are stunted etc, weakening the correlation between input and output; but in the equal one, all the variation in the output will be driven by the input.
At least I think that's what he's saying. Haven't read the book, and not really my field at all...
... published by The Guardian, no less. I am shocked and very pleased.
Another problem that Plomin encounters with explaining his findings is that people often confuse group and individual differences – or, to put it another way, the distinction between means and variances. Thus, the average height of northern European males has increased by more than 15cm in the past two centuries. That is obviously due to changes in environment. However, the variation in height between northern European males is down to genetics. The same applies to psychological traits.
“The causes of average differences,” he says, “aren’t necessarily related to causes of individual differences. So that’s why you can say heritability can be very high for a trait, but the average differences between groups – ethnic groups, gender – could be entirely environmental; for example, as a result of discrimination. The confusion between means and variances is a fundamental misunderstanding.”
What you're saying seems to suggest the distribution is multimodal. I'm not sure that's what they said.
I think that's backwards from what Plomin is saying in that quote. He's saying that, regardless of genetics, a better environment will cause the average performance of the group experiencing it to outperform the average performance of a group experiencing a worse environment. And he's saying that DNA influences the amount of each group's variation around that average performance. For example, if we were looking at height,
* There are two groups, 1 and 2; people in Group 1 have one kind of tallness DNA (tDNA, something I just made up), and people in Group 2 have another kind of tDNA; also, Group 1 grows up in an environment with better nutrition and exercise than Group 2. Both groups are one gender, let's say women, to simplify height statistics.
* Group 1 averages a height of 5'7" due to their relatively better environment, and due to their tDNA their variance is that 50% are between 5'5" and 5'8", a 3-inch range, and 95% are between 5'3" and 5'10", a 7-inch range.
* Group 2 averages a height of 5'5" due to their relatively worse environment, and due to their different tDNA their variance is larger: 50% score between 5'3" and 5'9", a 6-inch range, and 95% are between 5'0" and 5'11", an 11-inch range.
And yet until the industrial revolution, environmental factors were the dominant effect. Anyone could have been taller with enough nutrition.
Genes are only ever expressed under certain environmntal conditions. The minimal condition for all of them is being alive. Malnourishment, or perhaps too much caffeine, amongst a hundred other things, all determine how our genes for height express themselves.
Which is all to say, people are wrong when they say height is mostly genetic. It may be true enough under current social conditions though. I think the same problem applies to calling intelligence "largely" genetic.
Not arguing your idea in general, but the caffeine example is probably a myth[1].
[1] https://www.nytimes.com/2005/10/18/health/the-claim-drinking...
This is always what's meant. Perhaps it should be said more often... but nobody doubts that we can grow a bonsai.
The interesting question is how much do different factors matter in our present environment (and again ideally one should specify, e.g. rich-country & above-poverty-line, not just 201X) and in environments we might reasonably hope to create.
Reflex for instance, if u do an action long enough, it has been shown that a reflex curve grows in the brain, basically a "GOTO" in programming, which is a direct path. This directly increases performance, as can be seen in any sport, videogame or instrumentalist (music) This is "as muscle" as something can be.
There's an overemphasis on the cognitive/sensory part of the brain, which i take hindrance in, especially with AI development.
Motivation, Gut feeling, instinct, focus, excitement, persistence, self-motivation, annoyance, inspiration. I can list 100's of things, which hasn't even seen a single notion of being synthesized in AI, yet all these things, often not even aware, make us do what we do, and it's totally unknown how much of a factor they are in the grand scheme of our intelligence, and the ability to create/come to solutions by our own sentience.
imagine we synthesis fear in machines. Fear is what often keep us motivated. Closely tied to loss, losing people in a natural distaster creates incentive to fix/prevent. However, this only logically applies if empathy is present. Without empathy, no incentive to fix some other's bullshit. I don't get why these things are so grossly overlooked in our way to create more sentient machines. It's all so tied together in the simplest of human actions, that leaving it out seems a very un-scientific thing to do. Evolution of the human is it's own prove on how well such a system can work when it relies both on cognition as well as emotion.
Our mind only describes "how" we do what we do, but not "why" we do what we do.
/rant
https://www.youtube.com/watch?v=wfYbgdo8e-8
(Video is “You Are Two” by CGP Grey, 2016-05-31)
Zoom out far enough and nature and nurture are unified into a deterministic historical timeline. Freewill is an illusion and the universe is a static four-dimensional entity.
Also, how can we say anything about free will when we have not come to grips with defining the hard problem? Of course, if you want to model biological processes based on deterministic physics then free will does not exist. I’m simply suggesting that the fundamental assumption that are universe is deterministic is flawed.
Not really. A wave function propogates in a perfectly deterministic manner. There's not anything probabilistic baked into QM.
Probability comes in at what's called the Measurement Problem. Right now, we ad hoc apply the Born rule to project complex amplitudes into probability distributions whenever convenient, but there's actually no good understanding of why the Born rule works at all. It's just sorta tacked onto QM at this point.
I'm inclined to agree.
Personally show me one highly successful driven person that became that way by gambling everything and I'll show you five easy that broke.
It's a balance to both accept reality as it is while also striving to achieve things that we didn't know for sure were possible (or that we hadn't even conceived of yet!).
It seems that we must carefully straddle the boundary between the known and the unknown. Of course, this will look different for everyone.
I understood this to mean that to achieve your full potential ( naturally given potential ), you have to work hard and persevere.
A kenyan long distance runner might have a natural potential far greater than everyone else, but he still has to train to reach his natural potential.
> Is the ability to work hard and the mental fortitude not to give up not also something dictated by our genetics?
Genetics may predispose you to working harder and being mentally strong, but that's something you can change through hard work. You can't grow to be 7'5" like yao ming by working hard. You can't run as fast usain bolt by working hard. There are natural/genetic/physical limits. And there are natural predispositions.
I'm not a geneticist or a biologist so take it with a grain of salt.
It's something that came up a while back in a discussion with a friend on the concept of AI super intelligence. I personally don't think you would need superhuman IQ to run circles around humans. Superhuman focus and drive would do it. Something with a 150 IQ but able to operate like a person on amphetamine but minus the side effects and enter sustained periods of "flow state" focus at will would be godlike. Hell even mediocre IQ with superhuman focus would be scary.
We got back into contact with my older sister who had been adopted when I was about 12. She's absolutely the spitting image of her parents, both in looks and behavior, despite being raised in about as different a household as is possible.
Sometimes I wonder how I am a product of both my mom and my dad, because there are quite a bit of things in which I don't recognize myself in. If it was all nature, then it'd have been easier to spot and I'd also be addicted to a lot more things.
My upbringing was similar with regards to my mom (same people). But the situation was different, my grandpa didn't work much when I was around but was a workaholic during my moms time. My dad was beaten as a kid. I wasn't.
If it really is al genetics then how do you explain such a difference in socio-economic status? I think for them it's part drug abuse, a fucked up childhood and no nudge to do your best at school (in my dad's case, I don't know about my mom). I know that my dad had a propensity for learning but he never got to utilize it.
I'm pretty sure that if my dad had been in a better upbringing that he'd have fared better. I'm also pretty sure that if my momd would've been born around 1995 that she'd have fared better.
In that case, it could be justified to think of you as one of those wildcards that nature continuously throws into the mix to sharpen the species adaptability.
That is, if you spread your genes around and those also prove more adapted. And so on.
But somehow it's very controversial that the small intelligence differences between humans might be genetic, as if a species has a fixed IQ number, and the only IQ jumps are strictly between species, but not between individuals.
If people are talking about political ideology and wishful thinking, rather than science, then that's another matter. As the article says:
> those on the left have tended to see the environment as the critical factor because it ties in with notions of egalitarianism
I'm not quite sure what you're asking here. I feel that you and I must have drastically different starting assumptions, because your question seems meaningless in my context.
Do you dispute that Homo sapiens has a higher intelligence than H. erectus did? Than other primates?
Or are you alleging that the genetic basis for that intelligence difference shows no variation across human populations?
I feel like I have to stretch what you said to give it a charitable interpretation, but here goes: are you asking whether there's any evidence that the genetic component's variation across human populations contributes to significant phenotypic variation when compared to environmental factors?
The flaw is when you start to extrapolate that to things like racial issues. Saying that for example black people are less intelligent due to their genetics would ignore a lot of environmental circumstances that can lead to people not achieving their full potential. There's also the conclusion that if someone is born from a poor and dumb family that therefore their genetics must be worse and so forth.
Framing the argument as 'nature not nuture' would still ignore that if you had two people with identical genes born into a rich family vs a poor family that their theoretical 'genetic potential' is going to be highly limited by their environment. The genetic argument quickly becomes a tool with which to justify hurting others.
That particular assumption would be false because of genetic crossover. Two mentally disabled people could give birth to a genius child if recombination results in an offspring not carrying or expressing whatever causes their disability. The probability of this happening is higher if the pair is less closely related. The inverse can also happen of course, and does.
This is really why sexual reproduction seems to exist. It's also why the racial purity crowd has it precisely wrong. One hypothesis on the Flynn Effect is that it could result from increased outbreeding due to modern levels of travel and migration.
Here's my understanding of twin studies: you have some identical and fraternal twins. Each pair of twins are raised in the same household, and presumably experience the same environmental "nurture" effects. So, if we see stronger intellectual similarities between identical twins than fraternal twins, then we conclude that this difference is genetic.
But how valid is the assumption that the environments that fraternal twins face are as similar as those of identical twins? Let's assume for instance that: 1) women and men have the same innate potential for mathematical skill 2) our education system does a better job fostering mathematical ability in men than women 3) over time, this discrepancy causes women to score lower on tests of mathematical skill than men
While our identical twin pairs will all be of the same gender, the fraternal twin pairs may not. Two identical twin boys might receive the same environmental effects on their mathematical ability, but a girl and her twin brother will not, even if they have equal mathematical potential.
Given these assumptions, if we conducted a twin study on mathematical ability, we would see a stronger correlation between the scores of identical twins than those of fraternal twins, due to gender difference, and we would conclude that mathematical ability has a genetic component.
And our conclusion wouldn't be wrong! If gender impacts mathematical ability, and gender is genetic, then mathematical ability does arguably have a genetic component. But this gender difference comes about not because of an innate intellectual difference between women and men, but because of how a child's environment "nurture" changes depending on an arbitrary genetic trait "nature". In a world where these assumptions are true, a child's genes influence their future mathematical abilities - but in another world without gender-based educational discrepancies, the same genetic difference might not have any effect.
How do twin studies account for these more nuanced situations, where society causes nature and nurture to coincide in roundabout ways? Does it make sense to simply call these "second-order" socio-genetic effects "nature"?
I think it was a good point, that we have come a long way to equalizing the environment and that leaves a big part of the differences to genetics. I would say that is very high praise to the achievements we already made and shows that we are on the right way. I would guess that the same study made in a more unequal society would have different results.
The Economist called his paper disturbing (but interesting).
One would imagine that bringing facts to the table is a good thing, but apparently not.
https://academic.oup.com/ije/article/42/4/1057/656274
https://www.economist.com/science-and-technology/2014/08/21/...
"Plomin’s argument is that, in a society with universal education, the greatest part of the variation in learning abilities is accounted for by genetics...
...Thus, the average height of northern European males has increased by more than 15cm in the past two centuries. That is obviously due to changes in environment. However, the variation in height between northern European males is down to genetics"
To conclude that it is "nature not nurture after all" based on this argument, seems quite backwards.