Nothing but us big fat chickens around here


There are two kinds of people in this world: those who are deeply suspicious of twin studies, and those who welcome their confirmation that that their identity is fixed and heritable. I’m in the first group. I always have been. Maybe it’s something in my genes.

I first encountered the popular accounts of the Minnesota twin studies when I was a teenager, seeing the scientist and some of the twins doing the rounds of the afternoon talk shows — I think I saw them on the Mike Douglas Show (I’ve dated myself now). I remember them going on and on about the amazing similarities between the twins who had been raised apart. They both married women with the same name! They drank the same brand of beer! They were both volunteer firemen! They gave their dogs the same name! But while there were some recognizable similarities in the pairs, at the same time the obsession with superficial trivia wrecked the credibility of the stories. What? You’re trying to argue that my pet’s names are somehow encoded in my genome? It seemed to me that what we were seeing is echoes of similar culture in their upbringing (later confirmed: most of the twins weren’t really ‘separated’, but were raised by different relatives).

I also saw psychological tropes that ought to have been recognized. These were people who were rewarded for finding coincidences, and they avidly complied, and the scientists were readily accepting of coincidences as evidence of fundamental causal similarity. I was exposed to this pop genetics at the same time I was reading Fate magazine with a critical eye, and the stories were similar. I’d see stories that claimed to confirm the fact of reincarnation, for instance, by compiling lists of similarities between the contemporary claimant and their past life incarnation. They have the same birthday! Note the resemblances in this old-timey photograph! He lived in the Civil War era, now he is a Civil War re-enactor! He died in a fire, and now he’s afraid of fire!

It was exactly the same. That bugged me. And to this day I still see people touting the old twin studies as conclusively demonstrating the genetic basis of personality and intelligence, declaring that it has been positively confirmed that the heritability (a word they often don’t understand — genetically, it has a very narrow and precise meaning that isn’t exactly what they think it is) of intelligence is exactly 50%, meaning that half your IQ is determined by your genes (again, that’s not what it means), and therefore we should be more concerned with breeding intelligent people than teaching people. I also see this fandom coupled with other ugly associations — racists love it, as do Libertarians and simple-minded techno-fetishists. There are definitely genetic contributions to brain development and behavior, but human twin studies are deeply flawed and prone to exaggeration.

Stephen Hsu is a member of the gullible second group. He has posted a reply to my criticisms of his claim that we can readily ramp up human intelligence to reach an IQ of 1000 because hey, intelligence is obviously heritable. The twin studies say so.

1. Cognitive ability is highly heritable. At least half the variance is genetic in origin.

Yes. Cognitive ability is highly heritable, in a general sense — it’s built into the nature of being human that we all have a certain kind and degree of intelligence. We’re people, not chimpanzees or cats, and our brains are part of our genetic and evolutionary heritage. It is also the case that there is some variable component, the heritable part in the strict genetical sense of the word, and some of this variance is, as he says, genetic in origin. I’d argue that there are good reasons to doubt that it is as high as he claims. I’d also suggest no matter what the specific number attached to this variance might be, it does not imply that you can cheerfully fine-tune the genetics to ramp up intelligence to any arbitrary value you can name.

Talk to me when you’ve clearly defined “intelligence” (other than as the ability to perform well on intelligence tests) and have figured out how to isolate it from all the other variables, like class and education, that it is entangled in. Inventing new labels (like “cognitive ability”) does not increase understanding. Lumping a complex network of interacting traits into a single category of “intelligence” actively reduces understanding.

Much of Hsu’s complaint consists of incoherent pronouncements about the number of factors that contribute to “intelligence”. It’s thousands of alleles! It’s thousands of single-nucleotide polymorphisms! It’s tens to hundreds of genes!

Here’s the bottom line: I don’t care. Nobody knows yet, and it doesn’t matter whether it’s one gene that directly regulates “intelligence” or tens of thousands that modulate it, since you can’t even define genetically what is being measured. I suspect that there are going to be a lot of factors underlying the development and function of the brain, everything from cardiovascular health and nutrient processing and immune system effectiveness to genetic variants that affect synaptic vesicle fusion rates. Everything is pleiotropic. We’re not going to be able to sort out all the components cleanly, and in particular, we aren’t going to be able to genetically engineer a gene that has a positive contribution to intelligence without mucking up some other attribute of the organism.

But Hsu has an answer to that. Unfortunately, he only has one answer, because he seems to have read only one paper in genetics, and so he repeats it over and over.

It’s the damn chickens.

He showed them in the Nautilus article that first got my attention.


He used them in an article from last summer.


He drags them out in his rebuttal to me, which is almost entirely a copy-pasted repost of that earlier article.


Jebus, dude. Read another paper. The effectiveness of selection for quantitative traits is well known, with many examples. Look up milk production in dairy cattle. Bushels of corn produced per acre. Egg production by chickens, if you must indulge your avian fetish. Racehorse performance over time…oh, wait. No. Maybe you shouldn’t look that one up.

Thoroughbred horses have been bred exclusively for racing in England since Tudor times and thoroughbred horse racing is now practised in over 40 countries and involves more than half-a-million horses worldwide. The genetic origins of the thoroughbred go back largely to horses imported from the Middle East and North Africa to England in the late seventeenth and early eighteenth centuries. Since the establishment of the Stud Book in 1791, the population has been effectively closed to outside sources, and over 80% of the thoroughbred population’s gene pool derives from 31 known ancestors from this early period. Despite intense directional selection, especially on the male side, and the generally high heritabilities of various measures of racing performance, winning times of classic races have not improved in recent decades. One possible explanation for this is that additive genetic variance in performance may have been exhausted in the face of strong selection.

That paper actually finds that there is plenty of genetic variance present in the population of horses. It’s just not translating into rapid performance increases. It’s almost as if, when dealing with complex behavioral traits with many contributing factors, like running, that simply selecting for a single property, like muscle mass or mammary gland output or egg production, doesn’t work.

Hmm. I wonder if intelligence might not involve many interacting factors?

The IQ fanatics all seem to be stuck in a simplistic state of mind. They have a number, meaningless as it is, and now they must increase the number, as if it were grams of chicken meat, or dps in World of Warcraft, or number of tickets won at skee ball. And they think, since they have a number, it must be easy to make it a bigger number, just by doing more, and that there can be no limit to that number.

Anyone who suggests that there might be limits or that there might be more to the game than single-minded pursuit of a single reward is an obstructionist who will be proven false, eventually, by inevitable destiny.

So I’ve been getting this kind of nonsense from the usual techno-optimists.

PZ sounds like the guy that said humans were incapable of traveling 100 MPH.

I don’t know “the guy”, and I presume it was some old-timey dude talking about traveling on trains or whatever, but we’re talking about biology and genetics. I think I can confidently say that no human will be able to run at 100mph, ever, despite the fact that the men’s mile record has been reduced by 17% in the last 150 years. Running performance is a number! The number is getting better! Therefore, we’ll eventually have people running at 100mph, right?

Nope. Obviously.

The fastest land animal can run 70mph for short distances. That’s an upper bound for a specialized organism. There actually are physical limits to performance, and there are almost certainly physical limits to the performance of the brain, as well. We just don’t know what they are, yet. But blithely proposing that there are no limits, and that an IQ of 1000 is achievable, is as ludicrous as proposing that we tweak human genetics to get people outrunning cheetahs.

Furthermore, that paper on racing has an interesting idea: it compares the rates of improvement of running performance between horses, subject to intense breeding programs to increase racetrack speed, and humans, who are not being intentionally bred for running. Humans have been improving faster than horses, in spite of not benefitting from genetic optimization. How can that be?

The percentage change in winning time in the modern era (1950-2006) for the Epsom Derby, the Kentucky Derby and the men’s mile and men’s marathon relative to the average time recorded for each event from 1940-1949.

The percentage change in winning time in the modern era (1950-2006) for the Epsom Derby, the Kentucky Derby and the men’s mile and men’s marathon relative to the average time recorded for each event from 1940-1949.

For man, almost certainly the huge technological advances, increased awareness of physiological change during exercise and novel training methods have played a greater part than genetic endowment (Macarthur & North 2005). Since the 1950’s interval training, that is training at different paces during a single session, has become an integral part of all athletes programs and has undoubtedly improved fitness and thus racing times (Kubukeli et al. 2002). There is also a psychological incentive for human athletes to not only win races but to win them in record-breaking times (Abbiss & Laursen 2005).

It concludes that it would be interesting to see if “adoption of modern training methods to racehorse training, applying the principles of exercise physiology, nutrition and interval training” might produce more gains in horserace performance.

At a guess, intelligence is probably more similar to running speed than body mass, requiring multiple parameters to improve in concordance, and with all kinds of nested interactions. Intelligence isn’t something you can just bulk up with more protein!

There are a lot of other issues Hsu simply ignores. Two of them are evolution and ethics — he seems completely oblivious to both.

What are the evolutionary concerns? I brought them up before, but let’s simplify the problem here. The average IQ is 100 (by design). Yet there are plenty of people with an IQ of 150. If there are clear advantages to human beings getting smarter, shouldn’t we see some evidence that that positive variation increases its representation over time? But we don’t. We aren’t smarter than, say, the people who lived in the Renaissance era, or in classical Rome. Why don’t we look back on people in those earlier periods as, perhaps, all mildly retarded? I have a couple of explanations for why smarter than average people haven’t taken over the world.

  1. Selection doesn’t see an advantage to an IQ of 150. Sorry, smart people. Other people with an IQ of 100 seem to be well-adjusted, successful, and happy, and can cope with the modern world just fine. They also have children. There’s no particularly good reason to pressure the population to increase the frequency of hypothetical intelligence alleles.

  2. Higher IQs may actually be a detriment. Maybe there’s some side-effect of increased intelligence that selection can see — like delayed onset of reproduction, or an increase in the frequency of asocial cluelessness. Hsu’s superbright IQ 1000 humans might die out in a spiral of self-possessed misanthropic obsession.

  3. There may simply be physiological limits to how big an ape’s brain can be — it eats 20% of our energy output already — and genetics is approaching that limit. Maybe the reason we haven’t seen a big change in the capability of the human brain over the last 100,000 years is that we hit the ceiling then, and human genetic variation is just bouncing us around that level. We can’t exceed it without a radical alteration in the structure of the nervous system or our physiology, which won’t be achieved by Hsu’s proposal of just optimizing existing variants.

  4. The variation isn’t primarily a consequence of heritable traits at all — it’s a result of complex interactions between genes and environment, and is most readily affected by external influences, the equivalent of “principles of exercise physiology, nutrition and interval training” for the brain. So if there is some great benefit to having an IQ of 150, in the population at large you’ll find people who meet that criterion despite have detrimental SNPs, because they had the benefit of good nutrition and education, and people who have the SNPs Hsu wants to promote but don’t meet the criterion because they lacked good nutrition and education.

Maybe, just maybe, he ought to consider the fact that human health and happiness and success aren’t a consequence of a single quantitative trait. Maybe we’re complicated with many roles and many ways of meeting life’s challenges. Maybe we aren’t battery chickens.

But possibly the biggest flaw in his whole scheme is that even if he were right about the genetics, he hasn’t put the slightest thought into the ethics, or even simply the how of carrying out his grand scheme. He’s talking about experimentally manipulating an incredible number of human zygotes, with no appreciation of failure rates or even the possibility of side effects, and raising them to adulthood. He wants to manipulate the genetics of the nervous system, and doesn’t seem to be aware of how fraught with risks that is — and ethical experimenters always should consider how to handle failed outcomes.

Let’s imagine some hypotheticals.

So you’re tinkering with genes that affect brain size. Sometimes you’ll mis-edit, and you’ll get microcephalic embryos — easy to handle, just abort early. But sometimes you’ll succeed and get children with the larger brains you want, and then you discover that the cardiovascular system needed a tuneup, too. You’ve got a barracks full of 5 year olds who have constant debilitating migraines. Or they’ve got big brains starved for oxygen that are unable to develop. What do you do?

You’ve found some genes that directly affect the sensitivity of synaptic transmission. You’ve edited your flask full of ova (by the way, where did you get them?) to include this feature. They develop just fine. The nursery is full of babies. Every time you turn the lights on they go into massive epileptic seizures. You can’t even raise them to the point where they can start learning stuff because they’re suffering so much. What do you do?

The wealthy racist moneybags who is funding all your work is horrified to discover that you’ve obtained most of your gene variants from African populations (because that’s where most human genetic diversity is found) and cuts off your funding until you promise to only use pure Aryan sources. What do you do?

You’ve got a roomful of eager, healthy young students who’ve all had their genes tweaked in various ways. You’ve got to rank them. Which one is best? What do you measure?

You’ve got a roomful of eager, healthy young students who’ve all had their genes tweaked in various ways. It turns out that human children do not spontaneously aquire “intelligence” by instinct. Instead, they’ve got to be educated. Suddenly, your variables have spiraled out of control! Different children — excuse me, different polymorphisms — respond in different ways to different educational methods! What do you do?

These are just a few examples of considerations that are essential to contemplate before you blithely suggest that you’ll just use CRISPR/Cas to edit a bunch of genes in human embryos to create an imaginary genetic superman. Hsu does not or cannot consider them. He reminds me of the traditional physicist joke, which is where I’ll end this.


And that’s what I think of Stephen Hsu’s “genetics” calculations.


  1. says

    There is this peculiar fiction, held by certain academics, that genius is correlated with fitness.

    And there are totally certain developments in human natural history that relate certain brain developments to fitness– like speech, and eusociality, but IQ doesn’t actually test language arts or social skills. The emergence of society and culture are kinda central to the rise of man but we definitely exclude social factors from IQ tests.

    (I’m one of those people who doesn’t think general intelligence exists, and all IQ tests test are a person’s compliance with a certain academic model of intelligence, so that’s where I’m coming from on that.)

  2. cartomancer says

    As an identical twin myself, I’ve always found these bizarre tabloid “twin coincidences” things overblown and ridiculous. How much media attention do twins who differ quite substantially get, eh? How many scientific studies are published that conclude there isn’t much of a trend at all? My brother and myself were raised in pretty much the same way at the same time in the same place, and we ended up very different people. Knowing this served to inoculate me from the credulity.

  3. blf says

    Nothing but us big fat chickens around here — The mildly deranged penguin is not that confused / concussed / maniacal. Now yer average duck…

  4. Pierce R. Butler says

    Humans have been improving faster than horses… How can that be?

    No significant improvements for centuries in horseshoe technology.

    /Phil Knight

  5. says

    You’ve got a roomful of eager, healthy young students who’ve all had their genes tweaked in various ways.

    One of them is the next Julius Caesar and uses his intelligence to become the greatest politician ever, triggering massive destructive wars.

  6. Jake Harban says

    But possibly the biggest flaw in his whole scheme is that even if he were right about the genetics, he hasn’t put the slightest thought into the ethics, or even simply the how of carrying out his grand scheme. He’s talking about experimentally manipulating an incredible number of human zygotes, with no appreciation of failure rates or even the possibility of side effects, and raising them to adulthood.

    Well, if he were right about the genetics, then presumably the first step would be a proof of concept where you insert some of those “intelligence genes” into a chimpanzee or a bonobo and demonstrate that it does, in fact, bring a substantial increase in their intelligence.

    You can help him with that; I’ll help the structural engineers reinforce the statue of liberty.

  7. says

    There are ethical issues in manipulating chimpanzee genetics, too.

    Also with zebrafish.

    Real scientists don’t pretend they don’t exist.

  8. says

    You think horses don’t get doped?

    I didn’t say anything like that. Of course the horses are getting doped. I’m not a big fan of horse racing for lots of reasons but most of them have to do with the destructive effect on the horses. They run them very young and most of the horse-doping has been related to amphetamines (just what I want to get on, a juvenile horse that’s high on speed!) and painkillers (so the horses can run beyond the limits of their bodies with all the warning lights shut off) The fact that they run horses so young is doubtless a practice that evolved because it worked. Perhaps steroids don’t make as much of a contribution to just-pubescent horses. I don’t know. It’d be cruel and unethical to find out.

    I do get a laugh when people assume that change will always work out for the better. Because that’s implicit in the “better” part. What if a human with an IQ of 10,000 was an incredible manipulator? Or perhaps the greatest comedian ever? Or perhaps a public prosecutor? Or a marketer? Someone with insanely upgraded skills has as much of a chance of being a liability as a benefit to society as a whole. Do you get superman or lex luthor?

  9. Rossignol says

    One of them is the next Julius Caesar and uses his intelligence to become the greatest politician ever, triggering massive destructive wars.


  10. Cuttlefish says

    In my classes, we’d randomly pair up students and offer a prize to the pair who found the greatest number of coincidental similarities.

    It’s simply astonishing how many people were unknowingly separated at birth from their identical twin.

  11. Nerd of Redhead, Dances OM Trolls says

    We can have humans of 1000 IQ tomorrow. Redefine the median IQ from 100 to 500, and the standard deviation from 15 to 75. After all, it is just numbers (never mind what the numbers are really [mis]measuring).

  12. says

    One obvious question: what does an “IQ of 1000” even mean? I mean, AFAICT, IQ measurement is the result of taking a particular sort of test on which the average human performance is a score of 100 and the standard deviation normalized to 15. It may be (may be!) correlated to a particular sort of analytic skill. But I am pretty sure the test itself is designed to give a range of possible values and “1000” isn’t one of them (generally speaking, results which are 120 sigmas from the mean are not actually statistically useful).

    It’s like saying we could breed/train humans to get an SAT score of 9000. I don’t care how awesome your genetics/training program/cheating is, the scores just don’t go up that high.

  13. says

    Jake Wildstrom@#15:
    It’s like saying we could breed/train humans to get an SAT score of 9000. I don’t care how awesome your genetics/training program/cheating is, the scores just don’t go up that high.

    No, this one goes up to 11!!!

  14. Athywren - not the moon you're looking for says

    Isn’t IQ a moving target anyway? Even if humans ever do reach the dizzying heights of an average IQ of 1000, assuming they’re still using IQ in the same way to measure intelligence, then that’ll be 100.
    Much as I value rotational spatial awareness, and the ability to tell which things are like other things in the same way that different things are like yet more things, I have a very hard time finding a way to agree with the idea that this is what intelligence is. Part of it, yeah, definitely, but far from the whole.
    I can’t help but think that simply increasing our IQs and saying “we are smarter now!” is just as intellectually dangerous as spotting that there’s very little reason to believe that Ogopogo & the Bucca aren’t really real and saying “we are skeptics now!” That may well be an element of it, but it seems that nurturing a consistently useful and accurate process is far more important than getting a few of the results right.

  15. Holms says

    @pzmyers & Bostrom admits it’s speculative. But topic is worth exploring b/c low likelihood of success is countered by huge potential upside

    Sad that Pascal’s Wager is one of their primary arguments in favour of trying out every silly futurist idea ever. I wonder if it even occurs to them that it is the same rationale many religious apologists use?

  16. says


    But I am pretty sure the test itself is designed to give a range of possible values and “1000” isn’t one of them (generally speaking, results which are 120 sigmas from the mean are not actually statistically useful).

    There are people that would take intelligence tests and use the statistics to make meaningful generalizations and predictions about various phenomena.

    Then there are people who want to put their score on their vanity license plate; and there are also people who want to use IQ tests to justify the poverty, cultural exclusion, or oppression of whoever passes as “stupid.” People who talk about “1000 IQ” are mostly concerned with these latter entailments.

  17. slithey tove (twas brillig (stevem)) says

    I seem to remember there used to be a variation of Hsu’s postulate. Resulting in the “Mensa Sperm Bank” as resource for IVF’s, and the desire to ensure the baby will have a significantly above average Intelligence.
    Seem to recall that this venture failed, given the repeated non-performance of the results.
    I would think that this would give Hsu enough evidence that his proposal is futile (ie ‘null result’).
    ugh, whatever..
    IQ def’n — important to remember the Q is for “Quotient”. That it is an attempt to compare a single person intelligence in reference to the entire population. That it is also scaled as a percentage; so 100 is short for 100 percent, or exactly the same as the general population. ugh
    I think the highest that can be measured is approx. 200 so 10×100 is out-of-range.
    that’s all I can say intelligibly. All the nonsense about “breeding higher IQ” would result in incoherent ranting/babbling. need a break

  18. says

    Hsu and the rest might want to take a look at their pets to see the effects of aggressively trying to increase the likelihood of certain traits. The long ears on Springer Spaniels are attractive, but they also are more prone to ear problems. Persians and other cat breeds with very flat noses and faces have breathing problems. Bulldogs and some terriers have a high rate of Caesarian births because the puppies have heads too big for the mother’s birth canal. And on it goes.

  19. ragdish says

    I too join the choir in being highly critical of twin studies from Bouchard onwards. Y’all remember the early 90s with Phillip “the racist” Rushton. But before we throw the baby out with the bath water, I think well designed twin studies may have a role in mental health and pharmacology research. The genetics of major depression, bipolar illness and schizophrenia partly rely on twin research.

    Furthermore, we have to acknowledge that each of us likely have certain strengths and limitations that are in part shaped by our genes in given environmental contexts. For example, I recall in 1st year med school the challenges of memorizing the glycolytic pathway in biochem. Yet this was an easy task for my colleague. All she had to do was recite it once and she was able to visualize all the enzymes adding phosphates and splitting sugars. It took me at least 20 times and finally got it memorized before the finals by substituting the lyrics of Manfred Mann’s “Blinded by the Light”. A great example of nature and nurture but I wonder if my colleague had more nature on her side. Regardless, she quit medicine and now runs a bakery in Quebec City.

    I think my point is that nature and nurture in the individual is cool. But applying nature to groups wrt intelligence, then that’s harmful pseudoscience.

  20. CJO, egregious by any standard says

    It struck me, reading Hsu’s delusional rebuttal, that he’s a great case in point for why the basic idea (widely distributed sooper-genius = peace on Earth and a solution to humankind’s various dilemmas) is a non-starter.

    Because I’m sure Hsu has a quite high IQ. And yet he fervently believes this utter tripe. He believes that raising the average IQ of the population to his level will bring about these massive benefits to society.* But taking him as an example, it will just lead to a much higher number of arrogant Dunning-Kruger sufferers convinced that they have elegant solutions to complex problems.

    *Leaving aside the ridiculous goal of 1000 IQs, he says in the comments something to the effect that “just raising IQ a couple of standard deviations would be huge”

  21. says

    He’s talking about experimentally manipulating an incredible number of human zygotes, with no appreciation of failure rates or even the possibility of side effects, and raising them to adulthood.

    Sounds like someone who thinks Brave New World had it right.

  22. anbheal says

    I dated a twin for a year or so. One time she was attending to some pasta sauce, fresh out the shower, in a towel, wet hair. I strolled up to the stove and gave her a little butt-squeeze and a peck on the neck. She shrieked and yanked herself away. Cuz, well, it was the wrong twin, who was virtually indistinguishable from my girlfriend, when hairstyle and clothes were removed from the visual cues. The twin I was dating would have reacted totally differently. Ergo, nurture, not nature.

    Also, perhaps this is dated crap from the early 80s, but the conventional wisdom back then was that a horse doesn’t feel much pain popping out a colt-sized baby, while a human endures excruciating pain forcing out an underweight 6-pounder, because selection for hominid brain-size outpaced any selection pressure for pelvic width. If there’s any truth to that, then all of those engineered brainiacs with huge skulls (I’m picturing what we all called The Bumheads in the Star Trek pilot episode) would leave dead mothers on the delivery table. And then they’d turn into maladjusted psychopaths, never having known a mother’s love.

    How’m I doin’ with bad speculative pseudo-science???

  23. says

    One of the things that really strikes me about the arguments being made by Hsu, and those that agree with him, is that PZ’s objections to their arguments are really, really obvious, even to a non biologist such as myself. It makes me wonder if they have done any real thinking about their ideas, whether they have even tried to consider whether they could be wrong, or have flawed ideas. One would think, if they had, they would address them and create a more solid argument, rather than presenting fat chickens as an argument when it is clearly quite a silly comparison if one gives it more than a minute of thought. It is as though they never apply a single bit of critical thinking to their own ideas before tossing them out.

  24. says

    Or do they have such a cartoon version of biology and genetics in their head that it is not possible for them to imagine these problems with their arguments?

  25. says

    The basis for that 50% heritability argument isn’t just twin studies, but also studies of the frequencies of traits within families. You can get a rough estimate from that, as well…although subjective assessment often poisons the data, and shared environments also confound the analysis.

    So political party affiliation also has a strong heritability. Doesn’t mean it’s genetic, though.

  26. Matrim says

    Hmmm…well, according to Q an omniscient being has an IQ of 2005. Of course, this was on stardate 43539.1, so the mean may be different in the 24th century. Anyway, as long as we are making up shit, I say we shoot for that.

  27. chigau (違う) says

    I don’t think that Hsu actually read the chicken article.
    He just copied the picture.

  28. karmacat says

    In terms of psychiatric illnesses, twin and adoption studies were helpful early on. They stopped blaming mothers (mostly) and looked at these diseases as medical illnesses. They also found there were more winter births among people with schizophrenia, which made it important to look at epigenetic factors

  29. Joseph Felsenstein says

    Another concern about twin data is the inheritance of epigenetic marks. Correlation between identical vs. fraternal twins could be biased upward by epigenetic effects, and thus not give a good measure of genetic heritability.

  30. wzrd1 says

    Let’s go from a structural engineering route and generalized (OK, overgeneralized) genetic enhancement.
    We increase brain size three times. Double has a mass equivalent to a modern military combat helmet, something shed as quickly as safely possible (and even unsafely possible), due to it doubling the mass supported by the neck.
    Now, we have a chunk of meat on the top of a stalk of a neck that is barely, if at all supported by the neck and again, nutritional needs add to stress, as PZ mentioned above. The brain is a greedy critter, using a *lot* of our bodily nutrition, we add to that burden without adding circulatory support for the enlarged brain.
    Crippling migraines my butt, hypoxia and starvation would be more appropriate terms, with a brain too heavy to support for more than a few hours at best, before the neck would become so fatigued as to cause agony to the poor creature.
    Maybe it’d survive on Mars or the moon, but not under 1 G.

  31. Menyambal says

    Twice in my life I have sat through a group of people describing what made them unique, something they had or did, and realized that I had all those in common, just by virtue of being a bit older (I’d been in a parade, I’d petted a moose, I owned a ju-ju necklace). (Neither time did I have the sense to keep quiet about it.) So claiming that twins have stuff in common cuts no ice with me. Especially in a country with a monoculture.

    Along those lines, though, I can say that I know a man who had a half-brother he knew nothing of. They once were in the same crowd, in the same distant city, watching the same thing happen at the factory they both worked at. The jobs they had would have been ideal for the father they both knew little of. Well, they both knew of his life interest, and any inherited tendencies would have led to the same career path. The factory and the city were the closest place to pursue said interest. And it was a huge factory, hiring like crazy, and the entire staff was released to watch the event I mentioned. Otherwise, the two men wound up in different states, different careers, different lives entirely.

    The folks looking at growth curves seem to think everything starts off slow and goes bending up into a near-vertical asymptotic climb. Well, there’s another curve, a flattened S-curve, that starts the same way, and tapers off horizontally at an upper limit.

    The upper limit to human brain growth may be based on pelvic passages, cranial blood flow, suicidal tendencies, sheer embarrassment, utter uselessness, or all of the above. We may find something to get around some of those factors, only to run into others. But tweaking one thing is useless, and just assuming we haven’t been breeding for big brains is silly.

    We humans are the big-brain animal. That’s what we do. We have been pushing that as much as we can for a long time, and hitting limits such as how much can be pushed through a pelvis. But we’ve just gone through an Industrial Revolution, and cultural changes and medical advances. Yeah, we just might be able to tweak a gene, but we can already choose our diets, heal our diseases, access the internet and binge on all kinds of twisted stuff. We are only a few generations into that. Anything can happen.

  32. nutella says

    Twin studies were the basis of the biggest scientific scandal of the 1970s.

    Sir Cyril Burt was a very influential English educational psychologist and statistician. He demonstrated that intelligence was totally heritable by doing many studies of twins raised separately. His studies had so many twins that no one could compete (or figure out where he found so many). Since intelligence was innate, he advised the commission that developed the UK Eleven-plus exams that a single exam at age 11 was perfectly adequate to stream students into academic, standard, and vocational tracks.

    He was such an important scientist that no one successfully challenged his work until, after he died, someone “noticed that Burt’s correlation coefficients of monozygotic and dizygotic twins’ IQ scores were the same to three decimal places, across articles – even when new data were twice added to the sample of twins.”* It also was considered suspicious that his notes and records had been destroyed.

    Conservatives, who are of course very fond of the idea that intelligence is innate and has nothing to do with environment or education, were up in arms at the accusation that Burt had tampered with the results. One of them decided to defend Burt by working through all the twin studies in detail, sure that he would vindicate him. He did a thorough and honest job of it and had to publish the result that yes, it was almost certain that Burt’s twin study results were fudged.

    It was hugely controversial in the 1970s and still today Burt has his defenders. You’d think it would have made everyone suspicious of twin studies but it seems to be a story that people like to tell.

    * Quote from

  33. says

    Maybe, just maybe, he ought to consider the fact that human health and happiness and success aren’t a consequence of a single quantitative trait. Maybe we’re complicated with many roles and many ways of meeting life’s challenges. Maybe we aren’t battery chickens.

    One of the more disturbing aspects of their line of thinking is that they do seem implicitly to view humans in the same sick way many people view the chickens and other animals caught in the industrial food system. Naturally, the quantity of eggs chickens produce or the speed with which their bodies grow aren’t qualities bred in the chickens’ interests. Not only do they not contribute to the health or happiness of the chickens (difficult given their circumstances at any rate), but, for example, the rapid body growth of “broiler” chickens and other farmed animals itself results in immense pain and suffering, with their hearts and legs prone to give out entirely even before they’re dispatched at a very young age. There’s more attention among welfare advocates to the conditions of confinement in facilities than to the suffering they face confined in bodies that are bred purely for human exploitation. Of course this isn’t a problem for the industry as long as it doesn’t affect the bottom line.

    Even many of those who say, and likely believe, that they love the animals they breed hold some creepy and suspect views. Recently, I was reading a longer version of this article (by another author but same basic point). Here’s the relevant section:

    As I hinted at in the previous section, an obvious answer to solving golden retrievers’ cancer problems is to stop the inbreeding. Simply breed golden retrievers with other dogs and in a few generations, the risk should drop down to normal levels. Of course then you’d lose some of the traits that people want in a golden retriever.

    Another possibility is to find the gene involved, find golden retrievers that lack the gene version that increases their cancer risk, and breed only those dogs lacking the problem gene. The new golden retriever breed would then only have the usual 33% chance of getting cancer.

    This sounds great in theory but may not be possible in practice. First off, it may be that golden retrievers all have two copies of the gene version that increases their risk for cancer. If this is the case, then it may not be easy to find any golden retrievers that don’t have the trouble gene.

    A second reason is that the disease version of the gene might be involved in some trait that makes a golden retriever a golden retriever (think golden coat). If this is the case, then if you breed out the disease, you end up with a dog that isn’t a golden retriever anymore.

    These issues sound theoretical, but they aren’t. Something very similar happened with Dalmatians.

    Dalmatians are especially prone to kidney stones instead of cancer. Researchers found that all Dalmatians had two copies of the version of the gene that led to kidney stones meaning there was no easy way to breed it away.

    Breeders tried to engineer a Dalmatian without the kidney stone version of the gene by breeding them with the closely related Pointer. Eventually, through lots of breeding back with Dalmations, they got a dog that looked very much like a Dalmatian that didn’t suffer from kidney stones. Except that its spots were never quite right.

    Further study showed that Dalmatian spotting depended on the version of the gene that led to kidney stones. Get rid of kidney stones and you don’t have a true Dalmatian anymore. If something similar is happening in golden retrievers, it may not be possible to make a golden retriever less cancer prone.

    What this all means is that even if breeders find the responsible gene, they may not be able to do anything about golden retrievers’ increased cancer risk if they want to keep the golden retriever breed as is. Luckily for the dogs, having a gene version that increases your risk for cancer does not mean you will for sure get cancer.

    Yes, that is lucky. In the longer version, the author described how the dalmatian breeders had decided in the end that a propensity to suffer from kidney stones is “part of being a dalmatian,” as the “lovers” of golden retrievers might have to decide that a much higher risk of cancer is “part of being a golden.” That doesn’t say much for their professed love for the dogs.

    Even if people like Hsu could define some standard of human intelligence (which would presumably somehow work across all environments), which they can’t, I don’t know that the hypothetical migraine or epilepsy issues you raised would be any concern for them. They don’t seem all that interested in the health or happiness of the actual human beings people would hypothetically be creating. Aside from one rather stupidly employed quote from Flowers for Algernon, Hsu doesn’t seem to be claiming that super-intelligent people themselves would be happier or healthier. It appears those with “savant-like capabilities that, in a maximal type…: nearly perfect recall of images and language; super-fast thinking and calculation; powerful geometric visualization, even in higher dimensions; the ability to execute multiple analyses or trains of thought in parallel at the same time; the list goes on” are understood mainly as a potentially exploitable resource for others. Maybe not even in any material sense but in a twisted sense of pride or prestige. As I think you suggested in your earlier post these articles often seem less about hypothetical technologies and more about using future super-geniuses as a rhetorical device to “demonstrate” that intelligence is fixed and heritable (usually in patterns shaped by sex, race, and class) in the present.

  34. says

    Since I read this thread, something has been niggling at the back of my mind…

    What if it was possible to squeeze considerable extra “intelligence” out of existing brains by raising them to think better? Why assume that in the “nature versus nurture” debate, that nature always wins, especially given that nurture appears to already be a much larger factor? What if there were new, undiscovered, ways of thinking? I remember reading about Richard Feynman’s childhood and how he was raised – constantly stimulated and questioned and given a mixture of opportunity and work-to-get-the-opportunity. When you read biographies of the great physicists and mathematicians coming out of Hungary pre-war, they all had in common: the Hungarian tutoring and education system. Teller, Szilard, Von Neumann, Bethe*… They didn’t have bigger brains, they learned to think differently. Descriptions I’ve read of Von Neumann and Bethe’s calculating make it sound like they were parallel problem-solving – one thread starting at a rough approximation of the answer and the other crunching forward to meet in the middle. Fenyman’s thinking sounds like a mix of intuition and method.

    In his book “Aristoi” Walter John Williams hypothesizes a future society in which the powerful philosopher-kings induce disassociative personality ‘disorder’ into virtual selves that run as different semi-autonomous brain-threads. Perhaps specialization is possible, like Frank Herbert’s “mentat” who variously specialize in strategy, or being a human spreadsheet. In Joe Haldeman’s “None so blind” we encounter a character who asks whether a blind person can repurpose their visual cortex and become ‘smarter’ by adding the ability to process analysis visually as well as temporally. These are interesting ideas. Of course they have huge ethical problems, which all of the authors I referenced above dealt with to some degree. And, of course, there’s “flowers for algernon.”

    Why hasn’t Hsu considered the possibility that a higher “iq” might be a matter of upgrading the software, smoothing out the algorithms, parallelizing a bit here and there, and devising a training program that would amount to a better version of the BIOS running on established long-debugged hardware?

    I guess I’m kind of setting up a whole argument that leads to a closing quip like “Hsu, upgrade thyself” but it’s not coming together. But then I’m a lowly 1.0 and have a standard verbal training load with just a few moderate tweaks in the vocabulary department.

    (* raised with private tutors, Hungarian-style)

  35. ah58 says

    Personally, I think it’s much more likely that we’ll find a way to directly interface computers with our brain than to genetically increase our IQ to 1000.

  36. Vivec says

    I still fail to even see the utility of a 1000 IQ brain. Humans with perfectly normal brains working in concert with other humans can do amazingly complex and advanced things – like the various disciplines required for space travel, or even more mundane things like the complex web of utilities infrastructure.

    If anything, I think the bigger utility would come from bringing all humans as they currently are up to an even standard through better education and accommodation, rather than pipe-dreaming about living supercomputers that can, what, memorize every episode of General Hospital?

  37. says

    In theory it’s simple: Select for something long enough and it will happen. More or less. There are physical and biological barriers that can’t be solved by today’s wetware, how far evolution can take that given enough time is impossible to say. A billion years can make a lot of things happen, but within a few dozen (or even hundreds) of generation? That would take an insight to biology we just don’t have. Not by a long shot. We don’t have the knowledge on how genes affect us to do that, and we won’t figure that out for a very long time.
    It’s not just that we don’t know yet or that we can’t even define the metric to measure. Even the goal is wrong. Does peak IQ (whatever that means today) correlate with human prosperity? Which human characteristics [i]spectrum[/i] are we looking for? Do we even know the question we should ask?

  38. Lofty says

    Stephen Hsu might have better luck with his dream of breeding giant brains if he joins with the aquatic ape crowd. Now there’s a thought, don’t cetaceans have bigger brains already? What can you teach a whale?

  39. Sastra says

    As I recall all those “astonishing similarities between twins-separated-at-birth!!!” shows and articles back then weren’t promoting the significance of genetic inheritance; they were promoting ESP. Twins are supposed to have a special psychic bond. The dogs-with-the-same-name type of coincidence was being used as evidence for the paranormal.

  40. Menyambal says

    One of my memories of hanging out with a high-IQ group is a cartoon with a guy jumping up and down screaming, “Happy?! Happy!? I have an IQ of 162! How the hell can I be happy?”

  41. unclefrogy says

    this discussion reminds me of a short story I read long ago in Analog probably
    someone invented some medical procedure or other that gave everyone “supper brains” which worked for a little while until everything became so slowed down with discussion about the pros and cons of any action that the world was in danger of grinding to a complete stop until someone came up for a antidote that reduced the supper brains back to “normal” allowing things to get done again, it was delivered by plumbers and mechanics with squirt guns.
    what are the problems that 1000 IQ’s are supposed to address?
    If this kind of thinking persists all those strange aliens we encounter if science fiction will be self designed humans.
    uncle frogy

  42. Amphiox says

    @pzmyers & Bostrom admits it’s speculative. But topic is worth exploring b/c low likelihood of success is countered by huge potential upside

    It’s funny how they always only think about the “huge potential upside” and never consider the big potential downsides as well.

    Suppose this actually works. Honest to goodness no tricks works and you end up after your first batch of successful trials, with a group (it has to be replicable so you must have more than one) of a few hundred individuals each around 10X more intelligent (functionally useful, generalized intelligence) than the average person is now, with no downsides or drawbacks. How exactly do you think they are going to view themselves and their place relative to the rest of humanity, particularly when they inevitably find each other and start talking to each other and get that whole collaborative group intellect thing going among themselves? Whatever it is that they decide to do, one can be pretty confident that the rest of us won’t be able to stop them (intellects at that level will be thinking thoughts and devising plans that regular humans wouldn’t even be able to conceive of, let alone anticipate, plan for, counter or disrupt).

    We’d be lucky if they keep the rest of around as pets….

  43. irene says

    IIRC, another problem with the classic twin studies is that they did not have adequate checks for zygosity, meaning that some of the twins they thought were identical were in fact fraternal, and vice versa.

  44. wzrd1 says

    Menyambal, there already is some suggestion that selection is at work. Today, cesarean deliveries are increasing in prevalence, with argument over how many are over cephalopelvic disproportion issues.
    If the increase is due to cephalopelvic disproportion, surgical intervention is artificially selecting for increased skull size of neonates.

  45. leerudolph says

    (I’ve dated myself now)

    Unless, of course, you’ve dated your identical twin.

  46. bcwebb says

    IQ is currently defined as the skills to answer a heavily culture-driven set of peculiar questions. As others have pointed out Q is quotient, a ratio to the population average so changing the average is meaningless to IQ.

    The question of brain function is however fascinating as our brains do so many different things. Since we have only a minimal understanding of what we are actually doing even defining the question is complex and incomplete. We can identify some of the functions – sequential memory, mapping, pattern recognition, facial, voice and personal cadence recognition, social awareness, empathy, color/image/sound/musical/taste recognition/memory/retrieval, physical sense of location, body and muscle position, learned motions, the various things of athletic ability — the list goes on and on. When someone watches someone else dancing and then is able to position their own body to reproduce and rhythmically continue and interact with that dancer – what kind of intelligence is involved in that? A huge number of different things. When someone invents or calculates or influences someone to do something – what intelligence skills are involved? Simultaneously, i have a fantastic memory and am three brain cells away from completely forgetting what I did 2 years ago and who I met yesterday. Anyone who talks of optimizing intelligence is talking nonsense. And a dog has some impressive skills I lack. Similarly children have very different brain structures and connectivity from adults and have different skills – should I optimize child or adult features?

    On the other topic, I overlap with my twin a great deal in skills, flaws and some medical problems but we are different.

  47. ck, the Irate Lump says

    ah58 wrote:

    Personally, I think it’s much more likely that we’ll find a way to directly interface computers with our brain than to genetically increase our IQ to 1000.

    Yes, but that’s a rather unremarkable prediction. There’s lot of reasons to look at integrating technology into brains like making replacement eyes or ears for those who have lost their vision or hearing or just convenience and entertainment devices akin to modern cell phones. No, the real parallel to the (vaguely eugenic) IQ 1000 people are the techno-utopians who think we’ll upload our minds into computers and be able to live forever as digital personalities.

  48. slithey tove (twas brillig (stevem)) says

    re @54:
    I guess, to understand the 1000 IQ for the general population, requires treating IQ reference point like dollar values of historical commodities. EG “1804 trade of $10,987 (corrected into present dollars) worth of porcelain traveled the Pacific” Meaning the IQ reference population will be in reference to the population of a certain time.
    still meaningless overall

  49. says

    I have an IQ of 160.

    And I’m currently unemployed, have clinical depression and have few ideas about how to move forward in my life now that I know my natural aptitudes have nothing to do with the career I trained for. Hyper-focusing on IQ is irrational a fuck.

  50. wzrd1 says

    Two things irritate my life no end, when a finger decides to miss a key (or simply declines to press it enough to actuate it, despite my brain’s command) and when someone scrambles my keycaps. ;)

    Yeah, we’ve all done that one and worse. Some days, more worser than others, which are more gooder.
    Don’t mind me, I enjoy abusing the language until the language itself complains. :D

  51. Ichthyic says


    Myers is both confused and insulting in his blog post, but I’ll refrain from ad hominem attacks

    I… see…

    I see that I have no need to read further.

  52. emergence says

    This might not really be an issue, but what if there’s potential for people to start using developmental determinism once genetic determinism wanes in popularity? What if people who failed to get adequate nutrition or intellectual stimulation in their childhoods are seen as lost causes in adulthood? What if they’re treated as if they’ll never measure up to people who were lucky enough to have access to good nutrition and education when they were young? Once using genetics as a status symbol falls out of favor, I worry that upbringing will replace it.

  53. emergence says

    One other, very long point that I’d like to argue; l don’t think that technological or biological alteration of human physiology is inherently impossible or unethical, as long as you do it right and have (relatively) realistic expectations. That’s not to say that I buy into this Hsu guy’s crap, or most transhumanists’ crap for that matter.

    For one, I don’t like the idea of germ line genetic alterations for anything except possibly treating hereditary diseases. Even if alterations based on implanting electronics or synthetic tissue into people would be expensive as fuck, at least anyone could potentially get the procedure done at any point in their lives. It would probably also be easier to reverse any botched alterations with nasty side-effects.

    When it comes to tweaking people’s brains, I don’t see much value or plausibility in just pumping up people’s IQ scores. I realized a while back that “intelligence” is actually a collection of different mental traits rather than a single numerical value, so talking about “increasing” it like an RPG stat doesn’t make sense to me. Feel free to point out any problems with these, but I think that stuff like letting people neurally interface with electronics or rejuvenating aging brain cells are more plausible, worthwhile uses of neuroscientists’ time.

    It’s difficult to maintain your sympathies with an ideology when you realize that you don’t buy into a lot of its ideas. I’ve found that it prompts you to doubt even the ideas that you do agree with. For some reason, I still don’t want to fully write off the idea of human biological alteration. I’d like to think that at least part of the idea is plausible, and I don’t know whether learning more about biology will make it seem more plausible or not.

  54. davidrichardson says

    I train English teachers in Sweden and a lot of the studies we look at are from USA or Canada. Several of them reference ‘intelligence’ and I have to explain to my Swedish students that this is a particular North American cultural obsession – we have the same problems seeing it as a useful factor as PZ does, at least in our education system. There are a lot of factors which affect achievement in school system, but if genetics is one of them, we haven’t found any indication of this (yet?).

  55. says

    I agree that the fetishisation of an IQ as a holy grail is unhealthy and oversimplified. Intelligence is too complex phenomenon that cannot be reduced to one all-purpose-number.

    The issue is certainly complicated and difficult to untangle since there certainly are a lot of factors, but to say that

    …but if genetics is one of them, we haven’t found any indication of this…

    is just as simplistic false statement as saying that whe have an indication that genetics all there is. Brains are very plastic, but within some biologically set boundaries. Inherited genes certainly are one of the factors defining those boundaries – like any other organ.

  56. Intaglio says

    @ nutella thanks for publicising the information on Burt.

    @ SC (Salty Current) 2 words German Shepherds. The breed standard insists that they have a sloping back which leads to many spinal, pelvic and knee problems. These could be removed if Chinese sourced German Shepherds were brought in for breeding but the fashionable sloping back would vanish.

    My immediate problem with Hsu is his use of IQ scores because the only thing they measure is the ability to perform IQ tests. In any event they are renormalised every few years so that the average IQ is always 100. Other problems include the existence of many different types of intelligence (social, spacial, emotional, numerical and others), a cultural bias in the tests themselves and the lack of a standard test even within one culture.

    Mind you I must admit to bias myself; I find that most people who fixate on high IQ are happy to belong to a club called, in translation, “Table.”

  57. howardhershey says

    One of the more amusing features of heritability is that the more selective breeding for a trait one does the smaller heritability becomes.

  58. inquisitiveraven says

    In her book, Animals in Translation, Temple Grandin has an extended rant on the perils of single trait selection. One of the examples she provides is (wait for it) battery chickens. One of the issues that’s cropped from heavy selection for one or two traits that the industry finds desirable can be summarized in two words, “rapist roosters.” It turns out that one of the results of the industries intense selection is that Leghorn roosters have lost the ability to recognize when a hen is signaling readiness to mate, so when they see a female, they just jump on her.

    I don’t remember if German Shepherds came up, but she does have some harsh things to say about breeding Labrador retrievers for a calm temperament. Apparently, they end up to mellow to function as working dogs which is a problem because they’re one of the preferred breeds for service dogs, guide dogs for the blind especially, and that takes a certain level of assertiveness.

  59. says

    Regarding Luboš Motl’s argument:
    Counting the number of genes like that would probably be like counting letters in poetry. It’s not just genes working, it’s genes working together. The end result we call IQ or intelligence is as far as I can understand the end result of complex interactions of many genes in concert, and the resulting biology is in turn interacting with other persons. Quantify that if you can.

  60. pacal says

    One of the sources for the funding of Bouchard’s twin studies was The Pioneer Fund. Which over the years provided oodles of cash to Bouchard to fund his work. They also supplied oddles of cash to Jensen and the late Philippe Rushton.

    The Pioneer Fund aside from supporting such research has also provided much support for what can only be called racist political campaigns etc., over the years and it continues to do so. So in other words the twin studies got money from an organization dedicated to advancing a racist agenda. Obviously the Pioneer fund supported the Twin studies because they felt the results would support their larger political / social agenda. The Pioneer Fund was created by a wealthy American Business man, Wickliffe Draper who was a ardent Racist and Segregationist and an Anti-Semite. The Fund is still to this day tainted by that past and seeks to politically implement something like Draper’s vision.

    Two books go into some detail about the Pioneer Fund, William H. Tucker, The Funding of Scientific Racism: Wickliffe Draper and the Pioneer Fund, University of Illinois Press, Chicago, 2002, and Robert Wald, Sussman, The Myth of Race, Harvard University Press, Cambridge MASS, 2014, pp. 218-272.

  61. rietpluim says

    There are two kinds of people in this world: those who divide people in two kinds, and those who don’t.