[HN Gopher] The Breeder's Equation
___________________________________________________________________
The Breeder's Equation
Author : Bostonian
Score : 93 points
Date : 2021-11-13 12:54 UTC (10 hours ago)
(HTM) web link (www.edge.org)
(TXT) w3m dump (www.edge.org)
| ImaCake wrote:
| This is a pretty poor quality article. I say this as someone who
| works in a population genetics research group. If you like some
| actually thoughtful reading on genetics and eugenics I would
| point you towards gwern who, as far as I can tell, seems to at
| least get the science and math right.
|
| https://www.gwern.net/tags/genetics
| nfmcclure wrote:
| I'm very happy to see "The Breeder's Equation" on Hacker News.
| Wow. I spent my graduate career studying mathematical biology and
| working with biologists.
|
| It's a fascinating equation and I spent some time on it
| converting it from a discrete equation into a continuous equation
| along with explaining the use cases and motivations behind it
| here: http://fromdata.org/2013/10/27/the-continuous-breeders-
| equat...
|
| This of course, does not take into account mutation,
| transduction, conjugation and other sources of genetic variation.
|
| Edit: Please take these approximate expectation equations with a
| grain of salt. They only apply to larger, discrete-reproducing,
| controlled populations. Applying results like these on spatially
| segregated or small populations does not really work. Also this
| equation does break down a bit when the phenotypic trait is a
| result of very complicated interactions between genetics and the
| environment.
| paulcnichols wrote:
| Spicy topic!
| max_ wrote:
| "And of course the breeder's equation explains how average IQ
| potential is declining today, because of low fertility among
| highly educated women."
|
| Do highly educated women have a high IQ? Or does a high IQ make
| you a highly educated woman?
|
| The writer seems to start with the conclusion that highly
| educated women generally have high IQs.
| pjscott wrote:
| It's been found empirically that IQ and educational attainment
| are moderately correlated.
| fyhgdet wrote:
| The writer starts with that unstated assumption. It's not the
| conclusion.
| bayesian_horse wrote:
| The heritability of intelligence is overhyped, and in my opinion
| of no practical use.
|
| It's extremely hard to find data where it is even possible to
| distinguish between genetic and environmental influence. That
| would be the studies of the kind "twins raised apart". And that
| already excludes the reality that those twins will probably grow
| up in a similar background, similar health and educational system
| etc.
|
| The talk about heritable IQ is pointless, even dangerous, because
| it leads to complacency around issues around structural racism
| and equality in education.
| lmilcin wrote:
| This is dangerous view IMO. Knowledge should not be suppressed
| just because some people might interpret it incorrectly.
|
| If you fear the problem is "complacency around issues around
| structural racism and equality in education" then why not
| address those problems head on rather than propose to not talk
| about heritable IQ?
|
| I mean both structural racism and equality in education aren't
| at all difficult problems. They are only made difficult because
| large part of population is still effectively racist, has
| racist role models and has approval from government officials.
|
| It apparently is ok for people to be racist.
|
| If you are racist today, you can happily live with friends that
| have the same view and tune out the rest of the world that does
| not agree with you.
|
| And as long as it is ok for people to be racist they will
| always find some kind of excuse for their beliefs whether it is
| heritable IQ or something else.
| beebeepka wrote:
| It's been a tough week but I fail to pinpoint what you
| disagree with
| [deleted]
| daenz wrote:
| >The talk about heritable IQ is pointless, even dangerous,
| because it leads to complacency around issues around structural
| racism and equality in education.
|
| Can you say more about this? Why would it lead to complacency?
| If there is scientific merit to some ideas like IQ
| heritability, don't you think we need to find a way to
| incorporate those ideas safely into our formulation of society,
| rather than suppress them as heretical?
| pjscott wrote:
| The usual studies for disentangling genetics and environment
| involve twins raised _together:_ they get basically the same
| shared environment -- this is a feature, not a bug -- but
| identical twins are more closely related than fraternal twins.
|
| For example, say you're trying to find out how much of adult
| height comes down to genetics (in a modern, non-malnourished
| environment). You measure the heights of a bunch of twins and
| compare: how much more similar are the heights of identical
| twins than the heights of fraternal twins? Do a bit of
| calculating and you've got a number for heritability.
| sokoloff wrote:
| I'd expect if we find the kids of professors to be more likely to
| be National Merit Finalists that we'd find a non-zero
| upbringing/educational correlation. Sure there's a genetic
| component, but I'd be fairly shocked if "being good on academic
| testing" has no correlation with "being raised by academics".
| losvedir wrote:
| Of course it would be correlated. Genes and environment and
| culture and family are all just one big interrelated mess. Is
| it even possible to tease the contributions apart, even in
| theory?
|
| I guess I could imagine a study, something like: look at kids
| of professors, in particular identical twins vs fraternal. Not
| all children will be National Merit Finalists, but among those
| that are, do you find identical twin pairs more often? Even
| that is subject to environmental effects, though, because
| potentially identical twins are raised differently!
| bayesian_horse wrote:
| I remember something about studies about "twins raised
| apart".
|
| In my opinion, Human nature is too complicate to poke at many
| of these factors, and talking about genetics quickly devolves
| into racism and elitism.
| sokoloff wrote:
| I agree with your last, which is very unfortunate in that
| if we could figure a way via research to shift upward the
| effectiveness of cognition (for which IQ is a proxy
| measure), I think peoples lives overall would be improved.
|
| Some of these are interventions that we've already found to
| prevent wasting of ability (as you cite in another
| comment); others might be nutritional or environmental
| changes we could make to better support development in
| utero or as children develop.
|
| Giving everyone 5% "better brains" would be a huge win for
| the world, but the sociological factors you mention
| preclude widespread scientific study.
| LogonType10 wrote:
| You can't boost IQ, but you can stave off its decline
| with exercise. The reason why there's no incentive to do
| this is that no one wants smarter voters.
| sokoloff wrote:
| I agree with you but not the article which claims (without
| introducing evidence): " By the way, when we say
| "environmental," we mean "something other than additive
| genetics." It doesn't look as if the usual suspects--the way
| in which you raise your kids, or the school they attend--
| contribute much to this "environmental" variance, at least
| for adult IQ."
|
| Perhaps studies of early adopted children would another
| pathway for study, but there seems to be little appetite for
| IQ study in general.
| bayesian_horse wrote:
| I remember, without having googled anything additionally,
| studies where Malaria infections and lead exposition had a
| negative effect on final IQ, whereas deworming treatments
| and longer school attendance had a positive effect.
| civilized wrote:
| There are studies of twins raised separately that directly
| address this. We know a great deal about the genetic
| heritability of IQ, please have a look at this for more info:
| https://en.wikipedia.org/wiki/Heritability_of_IQ
|
| Extreme skepticism of social science findings is warranted for
| some subfields, but when it comes to intelligence, humanity has
| actually learned a lot.
| bordercases wrote:
| And I'd be shocked if being a good academic had nothing to do
| with heritable traits.
| s28l wrote:
| The author is playing fast and loose with definitions here. Other
| sources[0][1] (that I would consider more reputable) define the
| breeder's equation in terms of populations, but this author
| focuses on arbitrary and ill-defined subsets of populations.
|
| Crucially, the author defines R as "the response to selection",
| but he omits the second part: "from one generation to the next".
| Source [0] defines it even more clearly: "the change in the mean
| [of the population] over one complete generation".
|
| Similarly, S is the difference in the measured trait among the
| entire population and the population that reproduces. So when the
| author considers "a set of parents with IQs of 120", it only fits
| the correct usage of the equation if we take that to mean that
| mean IQ of all parents in this generation is 120. If that's his
| argument, how is he defining the population of parents?
|
| In my opinion, this is a wishy-washy argument that seems like a
| subtle way of advancing eugenics (or something similarly
| distasteful).
|
| [0]: https://www.nature.com/scitable/knowledge/library/the-
| breede... [1]:
| https://public.wsu.edu/~gomulki/biol519/presentations/Sjober...
| civilized wrote:
| I'd like to understand what this comment is saying, but I can't
| follow. Could someone please explain more clearly what exact
| intellectual mistake the author allegedly made? The exposition
| in the OP seems very simple and clear, and I cannot seem to
| relate the definitional issues raised here to what is said in
| the article.
|
| In the article's first thought experiment, we take a population
| with IQ 100, pull out the subset with IQ 120, have that IQ 120
| subset breed with one another. According to the breeder's
| equation, we get children with average IQ 110. What is
| "arbitrary", "ill-defined", "fast and loose", etc. about this?
| It seems to be a standard application of the equation, no
| different than how one might breed cows for milk or tomatoes
| for size. It's quite unclear how the "crucial" clause "from one
| generation to the next" undermines any of this.
|
| And could we perhaps focus on _understanding_ what was said
| before muddying the waters with unsubstantiated accusations of
| eugenics? HN rules say that HN is for learning and
| understanding, not ideological warfare.
| s28l wrote:
| The breeder's equation described the expected change in a
| _population_ from one generation to the next due to selection
| pressures (natural or artificial).
|
| For example, say a cattle rancher with a large herd may want
| to increase the average weight. So if he only breeds those
| animals in the top half of weight, what is the expected
| change in weight from one generation to the next?
|
| For another example, say a particular species of lizard is
| hunted by a species of bird. The faster lizards are more
| likely to escape under a rock than the slower lizards. What
| is the expected change in average speed from one generation
| to the next?
|
| Both of these examples have a well-defined _overall_
| population and _reproducing_ population. The value of S can
| be calculated. In the first example, it is the difference
| between the mean weight of the top half of cattle and the
| mean weight of the entire herd. In the second example, it is
| difference in the mean speed of the lizards that are able to
| reproduce before being eaten and the entire population.
|
| What are the analogous groups in the author's example? He
| doesn't define what distinguishes the population of 120 IQ
| parents from the population as a whole. In one reasonable
| reading, you could even think he means just two people when
| he says "a set of parents". That is what I mean about being
| fast and loose with terms: how are we defining the entire
| population and how are we defining the reproductive
| population?
|
| Further, he says that 120 IQ parents having children with
| mean IQ of 110 is an example of regression to the mean. I
| would say the exact opposite: the 110 IQ children _define the
| mean_ of the next generation (in the correct usage of the
| equation). The expectation is that if there continues to be
| positive pressure on IQ, then future generations will
| continue to have increasing IQs.
|
| With regards to "ideological warfare", the author himself
| explicitly introduced eugenics into the conversation with his
| analogy about the desert island populated by National Merit
| finalists (he literally described it as eugenics). His
| Wikipedia page [0] describes him as an anthropologist "who
| argues that cultural innovation resulted in new and
| constantly shifting selection pressures for genetic change,
| thereby accelerating human evolution and divergence between
| human races". I don't think it's unfair to say there are some
| unpleasant undertones to his work.
|
| [0] https://en.wikipedia.org/wiki/Gregory_Cochran
| civilized wrote:
| > He doesn't define what distinguishes the population of
| 120 IQ parents from the population as a whole.
|
| ...Surely what distinguishes them is that they have IQs of
| 120, whereas the parent population has average IQ of 100?
|
| > Further, he says that 120 IQ parents having children with
| mean IQ of 110 is an example of regression to the mean. I
| would say the exact opposite: the 110 IQ children _define
| the mean_ of the next generation (in the correct usage of
| the equation).
|
| Surely you understand there is not only one mean in play
| here? There is also the mean of the population from which
| the IQ 120 subset was drawn. It is their mean that
| "regression to the mean" normally refers to, and has
| referred to since Galton invented the concept in 1886.
|
| > With regards to "ideological warfare", the author himself
| explicitly introduced eugenics into the conversation with
| his analogy about the desert island populated by National
| Merit finalists
|
| Not all things "eugenics" are inherently evil. Genetic
| screening of embryos to avoid infant suffering from
| horrible genetic diseases is also eugenics. Should mothers
| not have a choice to save their children from horrible
| genetic diseases?
|
| It's ideological warfare to paint all eugenics with the
| same moral brush, as all having "unpleasant undertones".
| There is no moral flaw, per se, in seeking to understand
| how desirable traits might be increased in the human
| species.
|
| I can't speak on whatever research the author has done on
| "human races", but it does not seem relevant to the
| discussion of the breeder's equation or to eugenics in the
| broad, perfectly benign sense of increasing desirable
| traits in a population.
| Gregaros wrote:
| > It also explains why the professors' kids are a
| disproportionate fraction of the National Merit Finalists in a
| college town. [...] But those kids, although smarter than
| average, usually aren't as smart as their *fathers*: partly
| because their *mothers* typically aren't theoretical physicists,
| partly because of regression towards the mean.
|
| Wow, this guy is ... not concerned with political correctness/not
| considering whether or not the college professors worth
| mentioning are guaranteed to be male.
| jyscao wrote:
| Well, the context of your quoted statement was provided in the
| paragraph above:
|
| > Reminds me of the fact that Los Alamos High School has the
| highest test scores in New Mexico.
|
| He's referring specifically to the physicists working on the
| Manhattan project, who were definitely predominantly male.
| Gregaros wrote:
| That's not right, either, since he is speaking in the present
| tense and comparing his current local high school's attempts
| to emulate what Los Alamos high _currently_ does:
|
| > Reminds me of the fact that Los Alamos High School has the
| highest test scores in New Mexico. Our local high school
| tried copying their schedule, in search of the secret. Didn't
| work. I know of an approach that would, but it takes about
| fifteen years.
| jyscao wrote:
| I think you're simply reading too much into his imprecise
| usage of grammatical tense.
|
| "Our local high school" probably refers to when he was in
| high school himself decades ago, being born in 1953, that
| would put those years right around the time period when
| children of Manhattan Project physicists have demonstrated
| their academic talent.
|
| Given the fact that Los Alamos High School is not
| academically renowned in the current day, but was so half a
| century back, this is the only context in which his series
| of statements make any sense.
| rkk3 wrote:
| Ironic since their department, Anthropology, is one of the most
| politically-correct and female academic disciplines.
| LogonType10 wrote:
| Maybe they don't think anthropologists have high IQ.
| gumby wrote:
| > Eugenics is not only possible, it's trivial.
|
| If you select for a single, measurable trait, perhaps. We do this
| all the time, with limited success, in breeding lab test animals,
| dog breeds and such.
|
| But for survivability eugenics is hard: there are multiple dice
| rolls each cycle, not just the chromosomal mixing, but
| environment too, and that adds not just epigemetic change but
| different environments for which various traits might be
| temporarily valuable.
|
| You can see this demonstrated by the inbreeding of the royal
| houses of Europe. They have recognized this too as they have been
| widening their gene pool for decades.
|
| Even the magic island experiment described from which I extracted
| that sentence would suffer under that too.
|
| Selective pressure is _hard_.
| ImaCake wrote:
| > multiple dice rolls each cycle
|
| This is an understatement, just considering SNPs, there is at
| least several hundred thousand statistically independent coin
| flips when two parents breed. It is difficult to overstate how
| powerful an evolutionary tool this is, and the implications it
| has for breeding.
| Causality1 wrote:
| Like most looming disasters, whether or not this is a real
| problem depends on quantifying the problem. Is this likely to
| significantly affect the population intelligence before we learn
| to engineer our children, say within the next 200 years?
| bagels wrote:
| I always find these statements interesting. Do you think many
| people 200 years ago based their actions on what effect they
| would have on those people 200 years hence?
| baking wrote:
| Two people with IQ's of 120 will have kids with average IQ's of
| 110, but if you put those kids on an island and they have kids
| their average IQ's will be 110. What?
| AbrahamParangi wrote:
| The original population has an avg IQ of 100 but the new island
| population has an avg IQ of 110
| jasongi wrote:
| The parents genes are only 120 because 10 points were based on
| environmental "luck". Genetically they had the genes for 110 IQ
| +/- 10 points to accommodate the environmental luck.
|
| The two kids had average luck, so they got 110 IQ, but they
| still have the same genes. So when they have kids with others
| with the 110 IQ gene's, they will still be 110 +/- 10.
|
| A simpler explanation: you might be the child of geniuses but
| they dropped you on your head repeatedly as a baby. You might
| not be so smart as an adult because of it but your kids will
| have genius genes, not dropped on head genes.
| [deleted]
| mattnewton wrote:
| In the first example, their IQ of 120 is from a mix of factors
| and the author estimates some percentage that is due to the
| environment outside genetics, and that is what is lost in
| reverting to the mean of the environment. In the second example
| the author assumes that the environment of the desert island
| contributes nothing to genetics and so the offspring get the
| full 110 (heritability is 100%).
|
| It's odd to me though because it wasn't clear that the
| environment was meant to be affecting the parent and not the
| child too- the trick is the author treats the heritability
| parameter different for the parent and the child. Also, I don't
| think the desert island would actually have no effect on the
| 110 generation's IQ, or their upbringing outside of it, but I
| guess I can accept it as a thought-experiment-only place that
| does that by definition and not a literal desert island.
| wyager wrote:
| Wouldn't the 120 IQ subpopulation also have some people whose IQs
| are "genetically" more like 130 but they've gotten unlucky with
| environmental factors, pushing the genetic average a bit towards
| 120? It would be smaller than the number of 110 people who got
| lucky, but non-zero. Is this baked in to h^2?
| abeppu wrote:
| From a didactic perspective, I think he goes off the rails by
| immediately focusing on something as abstract and hard to measure
| as intelligence, and where there's a long history of people
| talking about whether it's even a single trait. In terms of just
| explaining the breeder's equation, I think he could have been
| more effective talking about, IDK, tall Dutch people.
|
| The other thing that's annoying here is that although this is an
| 'equation', as I understand it it's typically not predictive
| because that heritability term is so fuzzy. It's not that you
| know the heritability term in advance and predict the response to
| selection; measuring the response to selection also updates your
| information about the heritability.
|
| His examples have a cherry-picking feel for this reason. Take the
| "national merit finalists" thing he mentions multiple times. Note
| that he doesn't mention the IQ distribution of the college
| professors (surely it's logistically impractical to get any large
| number of busy faculty to spend time taking such tests) or of the
| college towns (which might not be the same as the overall
| population mean), or the degree to which being a professor is
| correlated with IQ or the degree to which being a national merit
| finalists is correlated to IQ. Had the data come out differently
| (and I suspect he mentions _finalist_ multiple times because
| there wasn't as distinct a signal among _winners_), this
| perspective leaves plenty of room to declare that (a) maybe
| heritability of intelligence is lower than initially thought or
| assortative mating along IQ lines is weaker than expected (b)
| maybe professor-ness is less correlated to IQ than assumed or (c)
| maybe national merit finalist status isn't especially correlated
| to IQ (semifinalists have to submit a bunch of info other than
| test results).
| pfortuny wrote:
| Even more so: every time IQ and regression to the mean is
| explained, it is always in the "more-to-less direction",
| whereas it works in both and both are relevant.
| mynameishere wrote:
| This kind of quibbling always comes up. He's just using
| professors and national merit finalists as examples.
|
| The truth is, you could probably take the top 10 percent
| highest-earning car salesmen (EDIT: and women), drop them on a
| desert island and, after two generations, get the highest-IQ
| society the world has ever known. But that's less obvious, so
| why use such an example?
| ImaCake wrote:
| But it's not clear at all that intelligence is a single
| trait. It is incredibly messy and this means any analysis of
| it has to be _very_ careful of confounders. In contrast,
| height is by many definitions a single trait, we know exactly
| what confounds it's measurement (and those things are easy to
| measure!) and we have a pretty good estimate of it's
| heritability.
| pjscott wrote:
| > (surely it's logistically impractical to get any large number
| of busy faculty to spend time taking such tests)
|
| You can estimate it decently by looking at SAT scores, which
| most professors will have taken at some point. Your error bars
| will be larger than if you administered IQ tests to everyone,
| but it's a lot easier.
| hirundo wrote:
| "And of course the breeder's equation explains how average IQ
| potential is declining today, because of low fertility among
| highly educated women."
|
| In the Heinlein universe, the Howard Foundation runs a voluntary
| eugenics program by paying people with particularly long lived
| ancestors to mate with each other. Protagonist Lazarus Long is a
| product of this.
|
| The author is saying that this would work as expected, with
| offspring gaining around 50% of their parents' extra longevity.
|
| I'm a firm opponent of any kind of coercive eugenics. But it
| seems like it would be a good use of a billionaire's fortune to
| establish such a foundation for the promotion of intelligence, by
| paying very smart people to make babies together.
|
| But in Heinlein, the "Howards" became reviled and were forced off
| of the planet. If we do create a particularly smart population by
| eugenics, perhaps their primary task should be to find a way to
| protect themselves from us normals, a treatment for tall poppy
| syndrome. Of course, the first resort is secrecy. So we wouldn't
| know if they already exist.
| throwvirtever wrote:
| An IQ is just a number coming out of a test. Whether or not
| that correlates to something useful for humanity, or even the
| individual being tested, is a different question. Surely the
| majority of useful discoveries are made by people with above-
| average IQs, but would juicing the numbers through eugenics
| really make much of a difference?
|
| How many extra Isaac Newtons would it take to make controlled
| nuclear fusion work? Because if we don't have an estimate for
| that, why would we expect an intelligence-focused eugenics
| program to be useful at all?
| PKop wrote:
| >why would we expect an intelligence-focused eugenics program
| to be useful at all?
|
| Are there no uses of a having a higher population average
| intelligence besides "does it immediately produce nuclear
| fusion"? Is higher average intelligence good for many many
| many other things besides producing fusion? Of course it is,
| this is an absurd premise.
|
| Also, where did nuclear fission get invented? Are there
| correlated differences in IQ of people from this region? Did
| nuclear fission get invented in areas with low average IQ?
|
| "An IQ is a just a number coming out of a test". Oh, but it
| does correlate with other group-wide achievements that aren't
| just numbers coming out of a test, does it not?
|
| >Surely the majority of useful discoveries are made by people
| with above-average IQs
|
| How it is not obvious then that increasing the average would
| also increase the level of the outliers and their ceiling?
| notahacker wrote:
| Not to mention the regression to the mean issue discussed in
| the article, and the slight problem of attracting women aware
| that they have a very high IQ to trade career success or
| other personal preferences for being the baby making machine
| for some billionaire's experiment. It's not like they're
| currently disproportionately likely to choose not to have
| kids because they can't afford them
| PKop wrote:
| >to trade career success or other personal preferences for
| being the baby making machine for some billionaire's
| experiment
|
| Why is it assumed that this isn't a more attractive
| proposition compared the alternative. Certainly there would
| be many, if not most or all, that would be willing to make
| this choice.
|
| The point you are implying is that "career success and
| personal goals minus children" > "making smart babies and
| being a mother"...where ">" can be more enjoyable or
| fulfilling. It's not clear that this is true. Part of "baby
| making" means leveraging that IQ in a productive way to
| raise strong, intelligent children, so it would not be
| going to waste.
| me_im_counting wrote:
| I'm a woman, and none of my smartest friends are
| interested in having more than 2 children. A few aren't
| interested in having any. I'm the weirdo who wants 3, but
| I don't see why I should be part of someone's experiments
| when I can find a high quality mate on my own anyway.
| Enginerrrd wrote:
| Yeah, it's interesting, humans already HAVE an incredibly
| complex sexual selection mechanism. There's all kinds of
| things that you are capable of selecting for without
| necessarily even realizing what you're doing. That
| selection pressure likely already includes the relevant
| things such a billionaire might care about, and many
| other things they can't even quantify, which likely
| includes genetic compatibility. The system we have has
| worked pretty well for a long time. It's hard to optimize
| such a complex and fuzzy thing.
| civilized wrote:
| So maybe the billionaire should enact his horrific
| eugenics experiment by creating a dating app to help
| women like you find high-quality men who want lots of
| kids.
|
| He'd even make money, because... well, be honest, how
| much would you pay for that if it really worked?
| notahacker wrote:
| > Why is it assumed that this isn't a more attractive
| proposition compared the alternative. Certainly there
| would be many, if not most or all, that would be willing
| to make this choice.
|
| I'm not sure why you're asking me this when your opening
| post in this exchange starts by noting low fertility
| amongst highly educated women. Smart women generally
| aren't short of offers from smart men to make babies with
| them (and the smart men are usually pretty wealthy). If
| "many, if not most or all" wanted to have lots and lots
| of kids instead of being academics or lawyers or rocket
| scientists, they'd already be doing it.
|
| I don't think a creepy eugenics foundation that's
| obsessed with the IQ of their kids makes the proposition
| _more_ attractive even if they 're paying enough for a
| slightly bigger mansion and the husband to afford to
| retire too.
| netflixandkill wrote:
| When affluent and educated societies worldwide show
| declining birthrates and increasing age at reproduction,
| it can be taken as a strong indicator of women's and
| family's preferences for fulfilling lives at demographic
| scale.
| pjscott wrote:
| > The author is saying that this would work as expected, with
| offspring gaining around 50% of their parents' extra longevity.
|
| Not for lifespan. What the author didn't mention is that this
| equation works for traits affected by a large number of genetic
| variants, each with small, roughly additive effects. Most
| heritable traits are like this, and if you plot the probability
| distribution for one, it looks like a normal distribution.
| Lifespan, on the other hand, is not at all normally distributed
| and you shouldn't expect it to work the same way as things like
| height.
|
| (Regarding your proposal, another idea that would probably be
| more cost-effective is to find people who are already extremely
| smart and clone them. More details:
| https://fantasticanachronism.com/2021/03/23/two-paths-to-
| the...)
| gwern wrote:
| Life span can be easily translated into standardized units
| more convenient to talk about which the breeder's equation
| would apply to, the same way binary or categorical or
| polytomous traits can often be treated as a normal latent
| with thresholds. And people calculate heritability of
| lifespan all the time. (It's low, but that's not because
| lifespan happens to be Gompertz-distributed.)
| robocat wrote:
| To add to your point, here is a distribution of heights:
| https://capitalaspower.com/2019/10/visualizing-power-law-
| dis... and here is a distribution of ages:
| https://siepr.stanford.edu/research/publications/life-
| expect...
___________________________________________________________________
(page generated 2021-11-13 23:01 UTC)