Genetics and Intelligence Robert Plomin



one of the areas of research I study is genetics and intelligence and it's one of the oldest studied questions in behavioral genetics going back to the late 1800s with Francis Galton here in England he was the cousin of Darwin for example the gentleman scholar did his research in his home and that sort of thing but he did some of the first work on intelligence and he did it very badly he studied he just studied reputation people who were thought to be very intelligent but what happened in the early nineteen hundreds of people developed measures of intelligence and even now that's contentious for some people but I think it's very well measured and it began with spearmint Charles Spearman in England in 1904 where he said intelligence just means too many different things to different people I mean what do you mean by intelligence really so he said I'm going to define it precisely g-general cognitive ability and what that is is what diverse tests of cognitive ability have in common so you've got hundreds of tests of cognitive abilities like different types of memory different types of verbal vocabulary fluency spatial ability there's many different types of cognitive tests but they all correlate substantially which is quite surprising to people you know you'd be good in verbal means on average you're probably pretty good in memory pretty good and spatial people's own on good at spatial I'm not good at verbal or vice-versa but they are pretty good they just mean they're better at this than that they correlate substantially so that 40% of the variance the individual differences of all those tests are in common and that's what we mean by gee the overlap the covariance among all these tests so it isn't a thing it's what these tests have in common so intelligence tests they're usually the major ones use around the world have about ten different tests they're different some are verbal some are non-verbal tests they're diverse tests and what you do is you put them together to get a score that people usually call an IQ score so it's a pretty good measure of general cognitive ability so general cognitive ability is important because it's the best predictor of society important things like educational outcome and occupational status by far than anything else we have there also among the most heritable tests and neuroscientists are becoming very interested in intelligence as well because it's how the brain works it's how the brain functions and it doesn't function in the way most neurocognitive new respect of psychologists think as little modules in the brain that light up when you do functional MRI the brain works it evolved as a general problem-solving tool and so it uses everything it's got to solve a problem so some of the tests that we celos most highly on G that is they correlate most with this concept of G are like abstract reasoning problem-solving in novel situations and I think people just see that you know if they just say well what do you think is intelligent why do you think they're intelligence it probably has to do with stuff like this it's not just how good you are on these quiz shows like here in England Col University Challenge where you just memorize a lot of facts that isn't really what we mean much by intelligence although to be good at that you have to be fairly intelligent so I mentioned this I emphasize the 6mp of the Oh intelligence what is that well it's one of the best measured things we have – one of the most important predictors we have so it's an important trait it's basically learn ability and say in terms of Education which I particularly say it's some kids learn more easily than other kids every any teacher will tell you that but instead of assuming it's all environmental we got to ask is it genetic and behavioral genetics over the century has shown that individual differences and intelligence are heritable if you take the world's literature of several hundred studies twin adoption family studies you come up with an estimate about 50% but what's really interesting underneath that is if you ask about development it turns out there's a linear increase in the heritability of intelligence from infancy to childhood to adolescence to adulthood infancy 20% childhood adolescence 40% adulthood 60% later in life 80% you first explain what heritability is that's the extent to which differences are due to genetic differences you ask them okay would heritability increase or decrease people will say it decreases why because Shakespeare's slings and arrows of outrageous fortune environmental differences accidents illnesses they all pile up which means that increasingly as you go through life the differences you see ought to be due to the environment but instead it's very much the other direction this has been replicated in many studies you know it's a really solid finding that in heritability of intelligence increases and so if you ask why you know why does this happen and it's what I was talking about before that the way genes work is they're not pro we don't program intelligence test scores in our DNA it allows you to learn more easily and you can learn more difficult subjects and then you choose environments that fit that you know you like to learn difficult things so you read different difficult things you argue with people you know you talk to people who want to discuss intellectual issues and so you create environments correlated with your genetic propensities so that the little differences early in life accounting for 20% of the variance and empathy snowball they increase as you go through life selecting and creating environments correlated with your genetic propensities so that's why I think the heritability of intelligence increases throughout life and I'm particularly interested in applying applying these techniques to education psychology about 23 years ago they didn't accept genetics at all and now it's very dumb everyone accepts genetics education however is this backwater where they don't accept science by and large you know you spend as much money on education as we do on the National Health Service the National Health Service now if you have a new idea a new program you've got to show empirically that it works you have to do randomized control trials in education people just use their hunches and you see so many examples of this I think they're going to have to deal with evidence and prove empirically scientifically that their programs work and then I think they will take genetics seriously right now they just say oh well that's just research and science you know that that doesn't have anything to do with education and it's bizarre because we find that cognitive traits and educational achievement are among the most heritable traits you know kids in England are the most tested kids in the world they have these national curricula and national tests that they take you know different stages in education we find in the first year of school literacy numeracy the things we teach in school are about 65% heritable the differences among kids even as they go into school are very substantially due to genetic differences the heritability of intelligence goes up so in the first few years of school the heritability of school achievement these test scores is higher than the heritability of intelligence then as the inheritability of intelligence goes up it becomes about on a par with the heritability of educational achievement there's a lot of interesting things that we find educational achievement is just as heritable for we call it STEM subjects science technology engineering math as it is for humanities for example so we also find that a lot of the genetic influence overlaps that is it's not just separate genes for learning math and separate genes for learning English it's largely the same genes and substantially that's what we call intelligence it's the same genes that affect all these different aspects of educational achievement when we talk about intelligence it's important to recognize that we're looking at individual differences why people differ on intelligence or educational achievement that's not to be confused with questions about why are humans more intelligent than other species or are we as an average more intelligent than people were before however there's quite a bit of interest in the issue of intelligence increasing that's called the Flynn effect he first noticed this it's been quite a big increase in intelligence over the last at least few decades it seems to have tapered off nobody knows exactly what that's about is it that we're becoming more sophisticated about test taking is it the way we standardize these tests so it's not really clear but what's important to recognize is that the causes of average differences like average differences between us and people 50 years ago or between sexes or ethnic groups have no necessary relationship to the causes of individual differences so a good example is the obesity epidemic we're not only getting may be more intelligent we're definitely getting fatter as all around the world in developed countries that's got to be environmental it's too quick to be genetic but the heritability of weight is just as great across the years across the decades so the causes of individual differences you might be surprised to know most people are we we've done surveys of this we have how heritable do you think height is people say really a heritable like 90% heritable meaning most of the differences are due to genetics weight not very much I mean 30% 40% maybe people say it's 60 70% most of the differences between us and weight are due to our inherited DNA differences even though we've been gaining weight over the decades the heritability has stayed high because the causes of individual differences aren't necessarily related to the average differences and a good possibility is we live we have a Stone Age brain that wants fat that is good if you're going to don't know when your next meal is but if you're in a fast food nation where you're bombarded by food cues all the time it's harder to resist that and so people who have a genetic propensity towards weight are going to put on that weight it's interesting to think about this on the environmental side hoes we're not talking about the average now we're talking about heritability that genetics accounts for a lot of the differences we see in intelligence so what if you were able to make a more equal society what that means is you get rid of the environmental differences you stop privileged you know parents passing on their wealth to their kids for example and giving them educational opportunities that other kids don't have if you can get rid of the environmental differences you don't get rid of the genetic differences so that the heritability increases with equal environments and that means that actually heritability is an index of social mobility of equality what's important about heritability which is the extent to which genetic influences explain behavioral differences we call it observe phenotypic differences I'm we're talking about in a particular population at a particular time with a particular mix of genetic and environmental factors we're describing what is what exists not what could be but now suppose those conditions change as they could change over time in a population or between different populations so say in a Mad Max apocalyptic world were be you know the environments are completely different how will that change heritability it certainly could change it it could actually make it greater because the genetic differences are more important I mean they're life or death issues that you solve all these new problems that you're confronted with you can't just coast on automatic pilot the way we can in our you know relatively civilized world where we know what's going to happen we're not too often surprised but so it's hard to know in the future and in terms of possible environments what would happen but what we do know is if you equate the differences in environments you actually increase heritability and I think that's a really interesting notion in terms equality of opportunity and suggesting that heritability is an index of equal environments

26 Comments

  1. kev ow said:

    To many confounding variables trying to determine how much is environmental and how much is genetic. Problem with most people who watch videos like this is that they dont understand weaknesses and strengths of studies. Most IQ studies are epidemiological studies on top of that lots of them are fishing expeditions. They will have multiple comparisons which cause false positives, high levels of heterogeneity etc. Lots of these studies show correlation not causation and false positives. In fact lots of epidemiological research tested under RCT'S end up being false. RCT'S also have massive weaknesses. If you have a good amount of intelligence you can see how many confounders life has that affects a persons cognitive abilities. Look at when a person is under high stress for a short period of time. You can see their cognitive abilities decline. Now imagine if you lived in a environment that is high stress all the time. Will long term stress decrease IQ probably. Also this dude is completely wrong about genetic influence on weight. I do research in exercise science and their no real research to back that. In fact when most people have trouble losing weight it's that they underestimate food consumption Massive cherry picker when it comes to research much like Rhonda Patrick. People feel like nurture vs. Nature always is one sided. Both things will play a hand. I think what people really want to believe dictates what side of the argument you're on.

    June 30, 2019
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  2. Blue -eyed said:

    Communists disliked this video.

    June 30, 2019
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  3. Arabi Daif said:

    You dumb fuckers
    Heritability has nothing to do with genetics
    Omg everyone here is so ignorant pretending to be smart and realists

    June 30, 2019
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  4. Art Boman said:

    Actually it could go either way. He predicted that if we got rid of family advantages then heritability (as a percentage of variation) would increase because environmental factors would decrease. But if iq is genetic then smart families can give advantages, maybe such large advantages(to people who are on average smarter) that they overshadow luck and chance and magnify outcomes by iq.

    June 30, 2019
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  5. zero vizible said:

    i can argue and prove intelligence is genetic.. i can prove it for hours if you talk to me. i live in pakistan.. is see clearly all the time.. retards all around.. even you guys think third world coutries why are not they clean.. because cleanliness is in mind i have observed carefully.. some people like clear streets and other dont mind them dirty,, it may look stupid what i have just said but all my 25 years of life i have observe how people behave what they see and what they understand about what they see.. and i must sy 99.993485834758347% of them are non sense. thats why my country is third world country even though we have lots of resources and opertunity to become civilized and first world country.. and let me tell you.. GERMANY is real brains for human kind and intelligence. and europe is the pinnacle of human civilization.. look at africa. the same time is given to africa and europe. and look where eurpe is and africa is. even after globalization when you have access to all basic priciples of science to invent or even reinvent or even even remake what europe has done in 1800s. africa cant do it now or even next 100s of years. thats how the gentics is.. Americans are all made up of europe and most of them are hybrids (cross between german frech english italian belgian danish etc etc etc) so they are little more clever but gentics always tends to fall to median.. all those hybrid baby boomers have laid the foundation of retards(current teen american generation) but now they have developed a system. in which they select the brains and leave the retards to run the economy and pay taxes for the sustainability of empire. and those clever people have take over the money power onto brain power.. but GERMANY is the real brains.. after that its frence england(half retards now) and other all european countries. north of the world is brains and south is empty skulls. south eat asians however are robots. they can make large synchronized lines decipiline goals and can work day and night but they may not have the understanding that Europeans does. you wont see and asian talking the words of humility and understanding the need of compassion towards the fellow human and animals. like in east asians it is most likely that a group of 100 boil a mouse and watch it without any pain. but it is least likely that 100 people in Europe do/witness or even let it be done in front of them or in their knowledge. japanese and koreans are intelligent but that is mostly due to the base scientific inputs given but eurpean inventions.. Even human behavior is extreemly gentics appart from intelligence. we are 9 siblings. and all 9 of us have the behaviou traits of my father and my mother (mostly father). and thats not environmental. or due to learning. i can clearly see what we learn from parent and do and what we do by ourselves that matches to what parents do.. only bits of behaviou matches but not mentality due to diversity of genes in offspring that the either of parent. my father looks to ones faces all the time (23 hours out of 24 hours if you sit in a same room) and my brother has the same tendency to look at once''s face. only difference is the intent of look and thinking while looking. my father looks and think what he is doing why he is doing and then comes up with totally wrong assumptions .. but my brother almost thinks nothing and make no assumptions at all he just looks on the face and thats the end of his looking story. 😀 i may sound like retard to you all and thats how it is.. no body can understand what i want to say and i am unable to tell what i want to say due to languge barrier and even in my mother language i dont have the sentences to tell how it all is and works. 😀 but i just know. my examples may be weak and look stupid but its okey for a common man to feel after reading it. there is a hell lot i dont know how to make examples or explain it

    Note: ignore all those spelling and grammer mistakes (there are alot in above paragraphic) but thats how my brain works.. i write "that" mostly on place where in my mind i am writing "than" .. i only find it out when i do a repeat reading (rereading) . i may have missed the Ss and es in end of most of words.. ignore mistake.

    June 30, 2019
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  6. BmgNewbie said:

    And just like that the lefts entire social engineering ideology vanished

    June 30, 2019
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  7. Kill All Pedos said:

    TLDW: blacks have lower IQ because genetics. Next!

    June 30, 2019
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  8. Genetic Alpha / Red Pill Reich said:

    IQ is 100% genetic https://www.youtube.com/watch?v=Y9OUhZy6B_s

    June 30, 2019
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  9. Sith'ari Azithoth said:

    Intelligence doesnt exist. There is no difference between crows, ravens and robins, other than size, shape and color. All the same. Same for dogs, same for humans. Circus music intensifies

    June 30, 2019
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  10. thomas petter said:

    being born with a low iq is a curse. Especially when the fields you like require a high iq. Being doomed to work a shitty job because the happenstance of an egg and sperm fusing is torture. It should be illigal to have kids without being 100% sure that their genes wont make them dumb, unmotivated or neurotic. If it ever were to become possible id love to gene edit myself out of this living hell.

    June 30, 2019
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  11. Luny Bunny said:

    Vladimir Ilyich Ulyanov; Mao Zedong, Joseph Vissarionovich Stalin and Adolf Hitler…. promoted in the worst possible way the pseudoscience called Eugenics (Racial Basis for Superiority), all defined containing statistical and mathematical data… Interesting Literature to Discuss: Proofiness: How You're Being Fooled by the Numbers by Charles Seife, Penguin, Sep 23, 2010, – Mathematics – 320 pages. The bestselling author of Zero shows how mathematical misinformation pervades-and shapes-our daily lives.

    "According to MSNBC, having a child makes you stupid. You actually lose IQ points. Good Morning America has announced that natural blondes will be extinct within two hundred years. Pundits estimated that there were more than a million demonstrators at a tea party rally in Washington, D.C., even though roughly sixty thousand were there. Numbers have peculiar powers-they can disarm skeptics, befuddle journalists, and hoodwink the public into believing almost…" (https://play.google.com/store/books/details?id=ghJaYi3FELMC)

    June 30, 2019
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  12. Vicente Senger said:

    Fascinating. The most interesting part is how highly intelligent people create environments that propel further increases in inherited intelligence. (5:20)

    June 30, 2019
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  13. altGoolam said:

    The real problem is not with the study of intelligence, but the way some people are applying it. You don't inherit your genes from your "race" either, because that exist. You inherit it from your parents.

    There's also the implicit cultural bias that are applied to these measures. Which is why white kids spend half of their lives trying unsuccessfully to replicate the arts of other cultures. They miss the perspectives necessary to replicate that culture, but by the standard of Whitists, they lack the intelligence.

    And then there's the self validating culture that we come to expect from Whitist society. We send our kids to private schools and provide extra coaching from an early age. But we measure other kids by their results without the support…

    We see you Whitists …

    https://www.jbhe.com/2019/02/study-finds-white-teachers-of-black-students-more-likely-to-punish-students-for-misbehavior/

    June 30, 2019
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  14. Mandalore the Stoic said:

    Over the decades there have been numerous attempts to debunk and dismiss IQ… they failed. And the reason that they failed is because IQ has predictive validity. If something has predictive validity it means that we can use it to make consistent accurate predictions. We can take a million people, all with an IQ 90, and we can basically give you a rough estimate for how many of them will serve prison time, how many of them will graduate college, the average amount of money they will make, heck we can even estimate how many of them will die in a car crash (because lower IQ people tend to drive faster, and are less likely to wear a seat belt).

    Environment is of course important, as this video explains. And IQ is by no means the only factor for determining 'success.' IQ also says nothing about whether you are a good person or not. There have been many intelligent people that have been complete monsters.

    Also, IQ doesn't necessarily have to mean 'smart.' What is smart is ultimately subjective. You can view IQ tests as nothing more than a tool for making predictions about a population or a person. And we are ALWAYS dealing in averages. An average does not mean 'all.' If a person has a 130 IQ we can give you a percentage for how likely you are to finish college. But even if you have a high likelihood of finishing college, that still doesn't guarantee that you will finish college or even be successful. My IQ is 131 and yet that didn't stop me from becoming an alcoholic (which luckily I was able to stop drinking, thank God). But yeah, my point is, IQ is a powerful tool for prediction, but please don't think its somehow going to decide your life for you.

    It does still matter though, and the reason why it matters is because the race IQ gap is a thing. Yes, Ashkanazi Jews have a higher average IQ than East Asians, and East Asians have a higher average IQ than non-Jewish whites, then Hispanics, and then blacks, and then Australian Aborigines. Its not racist, its just the grim reality we live in, and its nature being a total bitch as she often is. Again, I can't stress enough that we are talking about averages. Its not that all East Asians have a higher IQ than Hispanics, its that there are MORE East Asians with a high IQ then there are Hispanics with a high IQ.

    I'm not saying that racism doesn't exist, racism obviously exists. But disparities in wealth and income… racism just can't account for that. The idea that non whites are poor and always being thrown in jail because white people are oppressing them… that, quite simply, cannot be accounted for entirely by racism. IQ is playing a part here. Its by no means the only factor involved, but it is still a factor. And we're eventually going to have to accept that if we ever want to make things better.

    June 30, 2019
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  15. L S said:

    yes, intelligence genetics is just like body genetics.

    June 30, 2019
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  16. NoLxve Zzz said:

    Anyone thinking this is racist is actually below 100 iq. Heritability has to due with genetics and natural selection. It's not racism some groups are just genetically better. Although they do deserve the same amount of respect

    June 30, 2019
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  17. ahb boc said:

    When was the first year that Africa was recognized as a genetically retarded nation? I'm interested in reviewing data on the middle east.

    June 30, 2019
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  18. Paul Reverend said:

    I don't understand why people believe intelligence is caused by upbringing and nurturing rather than genetics. Perhaps they don't quite understand what intelligence is? Intelligence is not about rote memorization but rather about critical thinking, problem solving, and reasoning. Think about chess, anagrams, and Sudoku rather than rote memorization. A person with higher intelligence will always outperform a person with lower intelligence in tasks involving reasoning and critical thinking. Give both an engine to put together or a complex puzzle, and the more intelligent person will be able to put it together more quickly. Intelligent people learn easily through experience. I have a nephew who is a genius; he learned before his first day of school adding and subtracting by playing with his blocks and realizing when one block fell, the stack of blocks became one less. It's that ability of problem detection and logical thinking that defines a genius. Of course, our culture tells us we're our own masters and can do anything without limits. Is it then any surprise why people are more inclined to embrace the notion of intelligence being environmental?

    June 30, 2019
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  19. John De Luna said:

    I am not surprised that our education system is rejecting such idea. The literacy rate in the United States is a good example of such ignorance.

    June 30, 2019
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  20. Sigma Geranimo said:

    others got IQ
    another got EQ
    I got AssQ
    Trump supporter got only Q.
    🤦🏻‍♂️🧠🤸‍♂️

    June 30, 2019
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  21. 向你祖母問好 said:

    The contemporary education system is infested with low IQ people that falls under the "idiot savants" category (High knowledge low IQ) as teachers. An IQ test should be applied to teachers before they even go for their degree.

    June 30, 2019
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  22. MMC said:

    Learn what thow ?

    June 30, 2019
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  23. MegaSkilla said:

    Musculoskeletal development, hair color, eye color, melanin presentation, demeanor/temperament, and stress tolerance are all genetically inherited traits…yet according to leftists, "Intelligence," is an all or nothing proposition.

    June 30, 2019
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  24. Maxx Mabemwe said:

    The people of ancient Khemet thought they were it, Romans thought that they were it, Greeks thought they were it, Arabs thought that they were it, Persians thought that they were it, Sumerians same old same old, and so on. Now the Asian and the European think that they are it. What happened to all of those kingdoms that came before you? Whatever intellect you have was given to you by evolution, and history proves that it has a shelf life. H.G. Wells predicted that Asia and Africa would rise to prominence in the 21'st century. In America Christianity is the majority religion, and every Sunday preachers rant and rave about their book and it's god. Now there are certain things in the bible that they do not talk about, especially the scripture that says before Jesus returns "THE LAST SHALL BECOME FIRST". WTF!

    June 30, 2019
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  25. Maxx Mabemwe said:

    Plastic float out on the pacific ocean the size of Texas resulting in the killing off of aquatic and other marine life, decimation of the coral reefs , rivers and other water ways polluted through dumping toxic waste into them, fast food, murdering, raping, thieving, genocidal, criminals, poisoning of the air, and soil, deforesting the rain forest, dumping toxic waste into the air resulting in climate change, and then denying that it is happening, and you develop a test based on your ideas of what intelligence is and claim racial superiority. Question for all of you, so called, racially superior, intelligent, geniuses: How many races are there? Science, and even your religions, say that there is only one. The proof is in the fact that you can have a little man from Borneo with a bone through his nose, and a Scandinavian, blue eyed, 6' woman mate, and produce healthy wholesome off spring. That proves that they are of the same species, you call it race when talking about the human animal, so since there is only one race how can you have racial superiority? What you have on this planet, in the human population, is racial stupidity. Now go put on your MAGA cap, go to a Drumpf rally, listen to some more lies., and hear some " alternative" facts.

    June 30, 2019
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  26. Luis Carreiro said:

    if we all came from one source, how can my gene be more intelligent from everybody else?

    June 30, 2019
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