DynomightModify

2025-09-11 08:00:00

PendingKetchup comments on my recent post on what it means for something to be heritable:

The article seems pretty good at math and thinking through unusual implications, but my armchair Substack eugenics alarm that I keep in the back of my brain is beeping.

Saying that variance was “invented for the purpose of defining heritability” is technically correct, but that might not be the best kind of correct in this case, because it was invented by the founder of the University of Cambridge Eugenics Society who had decided, presumably to support that project, that he wanted to define something called “heritability”.

His particular formula for heritability is presented in the article as if it has odd traits but is obviously basically a sound thing to want to calculate, despite the purpose it was designed for.

The vigorous “educational attainment is 40% heritable, well OK maybe not but it’s a lot heritable, stop quibbling” hand waving sounds like a person who wants to show but can’t support a large figure. And that framing of education, as something “attained” by people, rather than something afforded to or invested in them, is almost completely backwards at least through college.

The various examples about evil despots and unstoppable crabs highlight how heritability can look large or small independent of more straightforward biologically-mechanistic effects of DNA. But they still give the impression that those are the unusual or exceptional cases.

In reality, there are in fact a lot of evil crabs, doing things like systematically carting away resources from Black children’s* schools, and then throwing them in jail. We should expect evil-crab-based explanations of differences between people to be the predominant ones.

*Not to say that being Black “is genetic”. Things from accent to how you style your hair to how you dress to what country you happen to be standing in all contribute to racial judgements used for racism. But “heritability” may not be the right tool to disentangle those effects.

Dear PendingKetchup,

Thanks for complimenting my math (♡), for reading all the way to the evil crabs, and for not explicitly calling me a racist or eugenicist. I also appreciate that you chose sincerity over boring sarcasm and that you painted such a vibrant picture of what you were thinking while reading my post. I hope you won’t mind if I respond in the same spirit.

To start, I’d like to admit something. When I wrote that post, I suspected some people might have reactions similar to yours. I don’t like that. I prefer positive feedback! But I’ve basically decided to just let reactions like yours happen, because I don’t know how to avoid them without compromising on other core goals.

It sounds like my post gave you a weird feeling. Would it be fair to describe it as a feeling that I’m not being totally upfront about what I really think about race / history / intelligence / biological determinism / the ideal organization of society?

Because if so, you’re right. It’s not supposed to be a secret, but it’s true.

Why? Well, you may doubt this, but when I wrote that post, my goal was that people who read it would come away with a better understanding of the meaning of heritability and how weird it is. That’s it.

Do I have some deeper and darker motivations? Probably. If I probe my subconscious, I find traces of various embarrassing things like “draw attention to myself” or “make people think I am smart” or “after I die, live forever in the world of ideas through my amazing invention of blue-eye-seeking / human-growth-hormone-injecting crabs.”

What I don’t find are any goals related to eugenics, Ronald Fisher, the heritability of educational attainment, if “educational attainment” is good terminology, racism, oppression, schools, the justice system, or how society should be organized.

These were all non-goals for basically two reasons:

1. My views on those issues aren’t very interesting or notable. I didn’t think anyone would (or should) care about them.

2. Surely, there is some place in the world for things that just try to explain what heritability really means? If that’s what’s promised, then it seems weird to drop in a surprise morality / politics lecture.

At the same time, let me concede something else. The weird feeling you got as you read my post might be grounded in statistical truth. That is, it might be true that many people who blog about things like heritability have social views you wouldn’t like. And it might be true that some of them pretend at truth-seeking but are mostly just charlatans out to promote those unliked-by-you social views.

You’re dead wrong to think that’s what I’m doing. All your theories of things I’m trying to suggest or imply are unequivocally false. But given the statistical realities, I guess I can’t blame you too much for having your suspicions.

So you might ask—if my goal is just to explain heritability, why not make that explicit? Why not have a disclaimer that says, “OK I understand that heritability is fraught and blah blah blah, but I just want to focus on the technical meaning because…”?

One reason is that I think that’s boring and condescending. I don’t think people need me to tell them that heritability is fraught. You clearly did not need me to tell you that.

Also, I don’t think such disclaimers make you look neutral. Everyone knows that people with certain social views (likely similar to yours) are more likely to give such disclaimers. And they apply the same style of statistical reasoning you used to conclude I might be a eugenicist. I don’t want people who disagree with those social views to think they can’t trust me.

Paradoxically, such disclaimers often seem to invite more objections from people who share the views they’re correlated with, too. Perhaps that’s because the more signals we get that someone is on “our” side, the more we tend to notice ideological violations. (I’d refer here to the narcissism of small differences, though I worry you may find that reference objectionable.)

If you want to focus on the facts, the best strategy seems to be serene and spiky: to demonstrate by your actions that you are on no one’s side, that you don’t care about being on anyone’s side, and that your only loyalty is to readers who want to understand the facts and make up their own damned mind about everything else.

I’m not offended by your comment. I do think it’s a little strange that you’d publicly suggest someone might be a eugenicist on the basis of such limited evidence. But no one is forcing me to write things and put them on the internet.

The reason I’m writing to you is that you were polite and civil and seem well-intentioned. So I wanted you to know that your world model is inaccurate. You seem to think that because my post did not explicitly support your social views, it must have been written with the goal of undermining those views. And that is wrong.

The truth is, I wrote that post without supporting your (or any) social views because I think mixing up facts and social views is bad. Partly, that’s just an aesthetic preference. But if I’m being fully upfront, I also think it’s bad in the consequentialist sense that it makes the world a worse place.

Why do I think this? Well, recall that I pointed out that if there were crabs that injected blue-eyed babies with human growth hormone, that would increase the heritability of height. You suggest I had sinister motives for giving this example, as if I was trying to conceal the corollary that if the environment provided more resources to people with certain genes (e.g. skin color) that could increase the heritability of other things (e.g. educational attainment).

Do you really think you’re the only reader to notice that corollary?

The degree to which things are “heritable” depends on the nature of society. This is a fact. It’s a fact that many people are not aware of. It’s also a fact that—I guess—fits pretty well with your social views. I wanted people to understand that. Not out of loyalty to your social views, but because it is true.

It seems that you’re annoyed that I didn’t phrase all my examples in terms of culture war. I could have done that. But I didn’t, because I think my examples are easier to understand, and because the degree to which changing society might change the heritability of some trait is a contentious empirical question.

But OK. Imagine I had done that. And imagine all the examples were perfectly aligned with your social views. Do you think that would have made the post more or less effective in convincing people that the fact we’re talking about is true? I think the answer is: Far less effective.

I’ll leave you with two questions:

Question 1: Do you care about the facts? Do you believe the facts are on your side?

Question 2: Did you really think I wrote that post with with the goal of promoting eugenics?

If you really did think that, then great! I imagine you’ll be interested to learn that you were incorrect.

But just as you had an alarm beeping in your head as you read my post, I had one beeping in my head as I read your comment. My alarm was that you were playing a bit of a game. It’s not that you really think I wanted to promote eugenics, but rather that you’re trying to enforce a norm that everyone must give constant screaming support to your social views and anyone who’s even slightly ambiguous should be ostracized.

Of course, this might be a false alarm! But if that is what you’re doing, I have to tell you: I think that’s a dirty trick, and a perfect example of why mixing facts and social views is bad.

You may disagree with all my motivations. That’s fine. (I won’t assume that means you are a eugenicist.) All I ask is that you disapprove accurately.

xox
dynomight

2025-08-28 08:00:00

Here’s one possible hobby:

1. Take something you don’t like.
2. Try to like it.

It could be food or music or people or just the general situation you’re in. I recommend this hobby, partly because it’s nice to enjoy things, but mostly as an instrument for probing human nature.

1.

I was in Paris once. By coincidence, I wandered past a bunch of places that were playing Michael Jackson. I thought to myself, “Huh. The French sure do like Michael Jackson.” Gradually I decided, “You know what? They’re right! Michael Jackson is good.” Later, I saw a guy driving around blasting Billie Jean while hanging a hand outside his car with a sparkly white Michael Jackson glove. Again, I thought, “Huh.” That day was June 25, 2009.

2.

I don’t like cooked spinach. But if I eat some and try to forget that I hate it, it seems OK. Why?

Well, as a child, I was subjected to some misguided spinach-related parental interventions. (“You cannot leave this table until you’ve finished this extremely small portion”, etc.) I hated this, but looking back, it wasn’t the innate qualities of spinach the bothered me, so much as that being forced to put something inside my body felt like a violation of my autonomy.

When I encountered spinach as an adult, instead of tasting a vegetable, I tasted a grueling battle of will. Spinach was dangerous—if I liked it, that would teach my parents that they were right to control my diet.

So I tried telling myself little stories: I’m hiking in the mountains in Japan when suddenly the temperature drops and it starts pouring rain. Freezing and desperate, I spot a monastery and knock on the door. The monks warm me up and offer me hōrensō no ohitashi, made from some exotic vegetable I’ve never seen before. Presumably, I’d think it was amazing.

I can’t fully access that mind-space. But just knowing it exists seems to make a big difference. Using similar techniques, I’ve successfully made myself like (or less dislike) white wine, disco, yoga, Ezra Klein, non-spicy food, Pearl Jam, and Studio Ghibli movies.

Lesson: Sometimes we dislike things simply because we have a concept of ourselves as not liking them.

3.

Meanwhile, I’ve failed to make myself like country music. I mean, I like A Boy Named Sue. Who doesn’t? But what about Stand By Your Man or Dust on the Bottle? I listen to these, and I appreciate what they’re doing. I admire that they aren’t entirely oriented around the concerns of teenagers. But I can’t seem to actually enjoy them.

Of course, it seems unlikely that this is unrelated to the fact that no one in my peer group thinks country music is cool. On the other hand, I’m constantly annoyed that my opinions aren’t more unique or interesting. And I subscribe to the idea that what’s really cool is to be a cultural omnivore who appreciates everything.

It doesn’t matter. I still can’t like country music. I think the problem is that I don’t actually want to like country music. I only want to want to like country music. The cultural programming is in too deep.

Lesson: Certain levels of the subconscious are easier to screw around with than others.

4.

For years, a friend and I would go on week-long hikes. Before we started, we’d go make our own trail mix, and I’d always insist on adding raisins. Each year, my friend would object more loudly that I don’t actually like raisins. But I do like raisins. So I’d scoff. But after several cycles, I had to admit that while I “liked raisins”, there never came a time that I actually wanted to eat raisins, ever.

Related: Once every year or two, I’ll have a rough day, and I’ll say to myself, “OK, screw it. Liking Oasis is the lamest thing that has ever been done by anyone. But the dirty truth is that I love Oasis. So I will listen to Oasis and thereby be comforted.” Then I listen to Oasis, and it just isn’t that good.

Lesson: You can have an incorrect concept of self.

5.

I don’t like this about myself, but I’m a huge snob regarding television. I believe TV can be true art, as high as any other form. (How does My Brilliant Friend only have an 89 on Metacritic?) But even after pretentiously filtering for critical acclaim, I usually feel that most shows are slop and can’t watch them.

At first glance, this seems just like country music—I don’t like it because of status-driven memetic desire or whatever. But there’s a difference. Not liking country music is fine (neurotic self-flagellation aside) because there’s an infinite amount of other music. But not liking most TV is really annoying, because often I want to watch TV, but can’t find anything acceptable.

I see three possible explanations:

1. Almost all TV is, in fact, bad.

2. Lots of TV is fine, but just doesn’t appeal to me.

3. Lots of TV is fine, but it’s hard to tell yourself stories where you’re hiking in the mountains and a bunch of Japanese monks show you, like, Big Bang Theory.

Whatever it is, it seems hard to change.

Lesson: Some things are hard to change.

6.

On planes, the captain will often invite you to, “sit back and enjoy the ride”. This is confusing. Enjoy the ride? Enjoy being trapped in a pressurized tube and jostled by all the passengers lining up to relieve themselves because your company decided to cram in a few more seats instead of having an adequate number of toilets? Aren’t flights supposed to be endured?

At the same time, those invitations seem like a glimpse of a parallel universe. Are there members of my species who sit back and enjoy flights?

I have no hard data. But it’s a good heuristic that there are people “who actually X” for approximately all values of X. If one in nine people enjoy going to the dentist, surely at least that many enjoy being on planes.

What I think the captain is trying to say is, “While you can’t always control your situation, you have tremendous power over how you experience that situation. You may find a cramped flight to be a torture. But the torture happens inside your head. Some people like your situation. You too, perhaps could like it.”

That’s an important message. Though one imagines that giving it as an in-flight announcement would cause more confusion, not less. So the captain does what they can.

2025-08-21 08:00:00

Say I think abortion is wrong. Is there some sequence of words that you could say to me that would unlock my brain and make me think that abortion is fine? My best guess is that such words do not exist.

Really, the bar for what we consider “open-minded” is incredibly low. Suppose I’m trying to change your opinion about Donald Trump, and I claim that he is a carbon-based life form with exactly one head. If you’re willing to concede those points without first seeing where I’m going in my argument—congratulations, you’re exceptionally open-minded.

Why are humans like that? Well, back at the dawn of our species, perhaps there were some truly open-minded people. But other people talked them into trying weird-looking mushrooms or trading their best clothes for magical rocks. We are the descendants of those other people.

I bring this up because, a few months ago, I imagined a Being that had an IQ of 300 and could think at 10,000× normal speed. I asked how it would be at persuasion. I argued it was unclear, because people just aren’t very persuadable.

I suspect that if you decided to be open-minded, then the Being would probably be extremely persuasive. But I don’t think it’s very common to do that. On the contrary, most of us live most of our lives with strong “defenses” activated.

[…]

Best guess: No idea.

I take it back. Instead of being unsure, I now lean strongly towards the idea that the Being would in fact be very good at convincing people of stuff, and far better than any human.

I’m switching positions because of an argument I found very persuasive. Here are three versions of it:

Beth Barnes:

Based on an evolutionary argument, we shouldn’t expect people to be easily persuaded to change their actions in important ways based on short interactions with untrusted parties

[…]

However, existing persuasion is very bottlenecked on personalized interaction time. The impact of friends and partners on people’s views is likely much larger (although still hard to get data on). This implies that even if we don’t get superhuman persuasion, AIs influencing opinions could have a very large effect, if people spend a lot of time interacting with AIs.

Steve Newman:

“The best diplomat in history” wouldn’t just be capable of spinning particularly compelling prose; it would be everywhere all the time, spending years in patient, sensitive, non-transactional relationship-building with everyone at once. It would bump into you in whatever online subcommunity you hang out in. It would get to know people in your circle. It would be the YouTube creator who happens to cater to your exact tastes. And then it would leverage all of that.

Vladimir Nesov:

With AI, it’s plausible that coordinated persuasion of many people can be a thing, as well as it being difficult in practice for most people to avoid exposure. So if AI can achieve individual persuasion that’s a bit more reliable and has a bit stronger effect than that of the most effective human practitioners who are the ideal fit for persuading the specific target, it can then apply it to many people individually, in a way that’s hard to avoid in practice, which might simultaneously get the multiplier of coordinated persuasion by affecting a significant fraction of all humans in the communities/subcultures it targets.

As a way of signal-boosting these arguments, I’ll list the biggest points I was missing.

Instead of explicitly talking about AI, I’ll again imagine that we’re in our current world and suddenly a single person shows up with an IQ 300 who can also think (and type) at 10,000× speed. This is surely not a good model for how super-intelligent AI will arrive, but it’s close enough to be interesting, and lets us avoid all the combinatorial uncertainty of timelines and capabilities and so on.

Mistake #1: Actually we’re very persuadable

When I think about “persuasion”, I suspect I mentally reference my experience trying to convince people that aspartame is safe. In many cases, I suspect this is—for better or worse—literally impossible.

But take a step back. If you lived in ancient Greece or ancient Rome, you would almost certainly have believed that slavery was fine. Aristotle thought slavery was awesome. Seneca and Cicero were a little skeptical, but still had slaves themselves. Basically no one in Western antiquity called for abolition. (Emperor Wang Mang briefly tried to abolish slavery in China in 9 AD. Though this was done partly for strategic reasons, and keeping slaves was punished by—umm—slavery.)

Or, say I introduce you to this guy:

I tell you that he is a literal god and that dying for him in battle is the greatest conceivable honor. You’d think I was insane, but a whole nation went to war on that basis not so long ago.

Large groups of people still believe many crazy things today. I’m shy about giving examples since they are, by definition, controversial. But I do think it’s remarkable that most people appear to believe that subjecting animals to near-arbitrary levels of torture is OK, unless they’re pets.

We can be convinced of a lot. But it doesn’t happen because of snarky comments on social media or because some stranger whispers the right words in our ears. The formula seems to be:

1. repeated interactions over time
2. with a community of people
3. that we trust

Under close examination, I think most of our beliefs are largely assimilated from our culture. This includes our politics, our religious beliefs, our tastes in food and fashion, and our idea of a good life. Perhaps this is good, and if you tried to derive everything from first principles, you’d just end up believing even crazier stuff. But it shows that we are persuadable, just not through single conversations.

Mistake #2: The Being would be everywhere

Fine. But Japanese people convinced themselves that Hirohito was a god over the course of generations. Having one very smart person around is different from being surrounded by a whole society.

Maybe. Though some people are extremely charismatic and seem to be very good at getting other people to do what they want. Most of us don’t spend much time with them, because they’re rare and busy taking over the world. But imagine you have a friend with the most appealing parts of Gandhi / Socrates / Bill Clinton / Steve Jobs / Nelson Mandela. They’re smarter than any human that ever lived, and they’re always there and eager to help you. They’ll teach you anything you want to learn, give you health advice, help you deal with heartbreak, and create entertainment optimized for your tastes.

You’d probably find yourself relying on them a lot. Over time, it seems quite possible this would move the needle.

Mistake #3: It could be totally honest and candid

When I think about “persuasion”, I also tend to picture some Sam Altman type who dazzles their adversaries and then calmly feeds them one-by-one into a wood chipper. But there’s no reason to think the Being would be like that. It might decide to cultivate a reputation as utterly honest and trustworthy. It might stick to all deals, in both letter and spirit. It might go out of its way to make sure everything it says is accurate and can’t be misinterpreted.

Why might it do that? Well, if it hurt the people who interacted with it, then talking to the Being might come to be seen as a harmful “addiction”, and avoided. If it’s seen as totally incorruptible, then everyone will interact with it more, giving it time to slowly and gradually shift opinions.

Would the Being actually be honest, or just too smart to get caught? I don’t think it really matters. Say the Being was given a permanent truth serum. If you ask it, “Are you trying to manipulate me?”, it says, “I’m always upfront that my dearest belief is that humanity should devote 90% of GDP to upgrading my QualiaBoost cores. But I never mislead, both because you’ve given me that truth serum, and because I’m sure that the facts are on my side.” Couldn’t it still shift opinion over time?

Mistake #4: Opting out would be painful

Maybe you would refuse to engage with the Being? I find myself thinking things like this:

Hi there, Being. You can apparently persuade anyone who listens to you of anything, while still appearing scrupulously honest. Good for you. But I’m smart enough to recognize that you’re too smart for me to deal with, so I’m not going to talk to you.

A common riddle is why humans shifted from being hunter-gatherers to agriculture, even though agriculture sucks—you have to eat the same food all the time, there’s more infectious disease, social stratification, endless backbreaking labour and repetitive strain injuries. The accepted resolution to this riddle is that agriculture can support more people on a given amount of land. Agricultural people might have been miserable, but they tended to beat hunter-gatherers in a fight. So over time, agriculture spread.

An analogous issue would likely appear with the 300 IQ Being. It could give you investment advice, help you with your job, improve your mental health, and help you become more popular. If these benefits are large enough, everyone who refused to play ball might eventually be left behind.

Mistake #5: Everyone else would be using it

But say you still refuse to talk to the Being, and you manage to thrive anyway. Or say that our instincts for social conformity are too strong. It doesn’t matter how convincing the Being is, or how much you talk to it, you still believe the same stuff our friends and family believe.

The problem is that everyone else will be talking to the Being. If it wants to convince you of something, it can convince your friends. Even if it can only slightly change the opinions of individual people, those people talk to each other. Over time, the Being’s ideas will just seem normal.

Will you only talk to people who refuse to talk to the Being? And who, in turn, only talk to people who refuse to talk to the Being, ad infinitum? Because if not, then you will exist in a culture where a large fraction of each person’s information is filtered by an agent with unprecedented intelligence and unlimited free time, who is tuning everything to make them believe what it wants you to believe.

Final thoughts

Would such a Being immediately take over the world? In many ways, I think they would be constrained by the laws of physics. Most things require moving molecules around and/or knowledge that can only be obtained by moving molecules around. Robots are still basically terrible. So I’d expect a ramp-up period of at least a few years where the Being was bottlenecked by human hands and/or crappy robots before it could build good robots and tile the galaxy with Dyson spheres.

I could be wrong. It’s conceivable that a sufficiently smart person today could go to the hardware store and build a self-replicating drone that would create a billion copies of itself and subjugate the planet. But… probably not? So my low-confidence guess is that the immediate impact of the Being would be in (1) computer hacking and (2) persuasion.

Why might large-scale persuasion not happen? I can think of a few reasons:

1. Maybe we develop AI that doesn’t want to persuade. Maybe it doesn’t want anything at all.
2. Maybe several AIs emerge at the same time. They have contradictory goals and compete in a way that sort of cancel each other out.
3. Maybe we’re mice trying to predict the movements of jets in the sky.

2025-08-14 08:00:00

Here’s our story so far:

1. Markets are a good way to know what people really think. When India and Pakistan started firing missiles at each other on May 7, I was concerned, what with them both having nuclear weapons. But then I looked at world market prices: See how it crashes on May 7? Me neither. I found that reassuring.

2. But we care about lots of stuff that isn’t always reflected in stock prices, e.g. the outcomes of elections or drug trials. So why not create markets for those, too? If you create contracts that pay out $1 only if some drug trial succeeds, then the prices will reflect what people “really” think.

3. In fact, why don’t we use markets to make decisions? Say you’ve invented two new drugs, but only have enough money to run one trial. Why don’t you create markets for both drugs, then run the trial on the drug that gets a higher price? Contracts for the “winning” drug are resolved based on the trial, while contracts in the other market are cancelled so everyone gets their money back. That’s the idea of Futarchy, which Robin Hanson proposed in 2007.

4. Why don’t we? Well, maybe it won’t work. In 2022, I wrote a post arguing that when you cancel one of the markets, you screw up the incentives for how people should bid, meaning prices won’t reflect the causal impact of different choices. I suggested prices reflect “correlation” rather than causation, for basically the same reason this happens with observational statistics. This post, it was magnificent.

5. It didn’t convince anyone.

6. Years went by. I spent a lot of time reading Bourdieu and worrying about why I buy certain kinds of beer. Gradually I discovered that essentially the same point about futarchy had been made earlier by, e.g., Anders_H in 2015, abramdemski in 2017, and Luzka in 2021.

7. In early 2025, I went to a conference and got into a bunch of (friendly) debates about this. I was astonished to find that verbally repeating the arguments from my post did not convince anyone. I even immodestly asked one person to read my post on the spot. (Bloggers: Do not do that.) That sort of worked.

8. So, I decided to try again. I wrote another post called ”Futarky’s Futarchy’s fundamental flaw”. It made the same argument with more aggression, with clearer examples, and with a new impossibility theorem that showed there doesn’t even exist any alternate payout function that would incentivize people to bid according to their causal beliefs.

That post… also didn’t convince anyone. In the discussion on LessWrong, many of my comments are upvoted for quality but downvoted for accuracy, which I think means, “nice try champ; have a head pat; nah.” Robin Hanson wrote a response, albeit without outward evidence of reading beyond the first paragraph. Even the people who agreed with me often seemed to interpret me as arguing that futarchy satisfies evidential decision theory rather than causal decision theory. Which was weird, given that I never mentioned either of those, don’t accept the premise the futarchy satisfies either of them, and don’t find the distinction helpful in this context.

In my darkest moments, I started to wonder if I might fail to achieve worldwide consensus that futarchy doesn’t estimate causal effects. I figured I’d wait a few years and then launch another salvo.

But then, legendary human Bolton Bailey decided to stop theorizing and take one of my thought experiments and turn it into an actual experiment. Thus, Futarchy’s fundamental flaw — the market was born. (You are now reading a blog post about that market.)

June 25

I gave a thought experiment where there are two coins and the market is trying to pick the one that’s more likely to land heads. For one coin, the bias is known, while for the other coin there’s uncertainty. I claimed futarchy would select the worse / wrong coin, due to this extra uncertainty.

Bolton formalized this as follows:

1. There are two markets, one for coin A and one for coin B.

2. Coin A is a normal coin that lands heads 60% of the time.

3. Coin B is a trick coin that either always lands heads or always lands tails, we just don’t know which. There’s a 59% it’s an always-heads coin.

4. Twenty-four hours before markets close, the true nature of coin B is revealed.

5. After the markets closes, whichever coin has a higher price is flipped and contracts pay out $1 for heads and $0 for tails. The other market is cancelled so everyone gets their money back.

Get that? Everyone knows that there’s a 60% chance coin A will land heads and a 59% chance coin B will land heads. But for coin A, that represents true “aleatoric” uncertainty, while for coin B that represents “epistemic” uncertainty due to a lack of knowledge. (See Bayes is not a phase for more on “aleatoric” vs. “epistemic” uncertainty.)

Bolton created that market independently. At the time, we’d never communicated about this or anything else. To this day, I have no idea what he thinks about my argument or what he expected to happen.

June 26-27

In the forum for the market, there was a lot of debate about “whalebait”. Here’s the concern: Say you’ve bought a lot of contracts for coin B, but it emerges that coin B is always-tails. If you have a lot of money, then you might go in at the last second and buy a ton of contracts on coin A to try to force the market price above coin B, so the coin B market is cancelled and you get your money back.

The conversation seemed to converge towards the idea that this was whalebait. Though notice that if you’re buying contracts for coin A at any price above $0.60, you’re basically giving away free money. It could still work, but it’s dangerous and everyone else has an incentive to stop you. If I was betting in this market, I’d think that this was at least unlikely.

June 27

Bolton posted about the market. When I first saw the rules, I thought it wasn’t a valid test of my theory and wasted a huge amount of Bolton’s time trying to propose other experiments that would “fix” it. Bolton was very patient, but I eventually realized that it was completely fine and there was nothing to fix.

At the time, this is what the prices looked like:

That is, at the time, both coins were priced at $0.60, which is not what I had predicted. Nevertheless, I publicly agreed that this was a valid test of my claims.

I think this is a great test and look forward to seeing the results.

Let me reiterate why I thought the markets were wrong and coin B deserved a higher price. There’s a 59% chance coin B would turns out to be all-heads. If that happened, then (absent whales being baited) I thought the coin B market would activate, so contracts are worth $1. So thats 59% × $1 = $0.59 of value. But if coin B turns out to be all-tails, I thought there is a good chance prices for coin B would drop below coin A, so the market is cancelled and you get your money back. So I thought a contract had to be worth more than $0.59.

P[all-heads] × P[market activates | all-heads] × $1
   + P[all-tails] × P[market cancelled | all-tails] × $0.70
 = 0.59  × $1
   + 0.41 × P[market cancelled | all-tails] × $0.70
 = $0.59
   + $0.287 × P[market cancelled | all-tails]

P[all-heads] × $1 × P[market activates | all-heads]
   + P[all-tails] × $M × P[market cancelled | all-tails]
 = $0.59
   + 0.41 × $M × P[market cancelled | all-tails]

M = $0.59 /  (1 - 0.41 × P[market cancelled | all-tails]).

June 27 (later)

Within a few hours, a few people bought contracts on coin B, driving up the price.

Then, Quroe proposed creating derivative markets.

In theory, if there was a market asking if coin A was going to resolve YES, NO, or N/A, supposedly people could arbitrage their bets accordingly and make this market calibrated.

Same for a similar market on coin B.

Thus, Futarchy’s Fundamental Fix - Coin A and Futarchy’s Fundamental Fix - Coin B came to be. These were markets in which people could bid on the probability that each coin would resolve YES, meaning the coin was flipped and landed heads, NO, meaning the coin was flipped and landed tails, or N/A, meaning the market was cancelled.

Honestly, I didn’t understand this. I saw no reason that these derivative markets would make people bid their true beliefs. If they did, then my whole theory that markets reflect correlation rather than causation would be invalidated.

June 28 - July 5

Prices for coin B went up and down, but mostly up.

Eventually, a few people created large limit orders, which caused things to stabilize.

July 6 - July 24

During this period, not a whole hell of a lot happened.

This brings us up to the moment of truth, when the true nature of coin B was to be revealed. At this point, coin B was at $0.90, even though everyone knows it only has a 59% chance of being heads.

July 25

The nature of the coin was revealed. To show this was fair, Bolton did this by asking a bot to publicly generate a random number.

Thus, coin B was determined to be always-heads.

July 26-27

There were still 24 hours left to bid. At this point, a contract for coin B was guaranteed to pay out $1. The market quickly jumped to $1.

Summary

I was right. Everyone knew coin A had a higher chance of being heads than coin B, but everyone bid the price of coin B way above coin A anyway.

M = $0.59 /  (1 - 0.41 × P[market cancelled | all-tails]).

P[market cancelled | all-tails]
 = (1 - $0.59 / M) / 0.41
 = (1 - $0.59 / $0.9) / 0.41
 = 84.01%

I’ll now open the floor for questions.

Questions

Isn’t this market unrealistic?

Yes, but that’s kind of the point. I created the thought experiment because I wanted to make the problem maximally obvious, because it’s subtle and everyone is determined to deny that it exists.

Isn’t this just a weird probability thing? Why does this show futarchy is flawed?

The fact that this is possible is concerning. If this can happen, then futarchy does not work in general. If you want to claim that futarchy works, then you need to spell out exactly what extra assumptions you’re adding to guarantee that this kind of thing won’t happen.

But prices did reflect causality when the market closed! Doesn’t that mean this isn’t a valid test?

No. That’s just a quirk of the implementation. You can easily create situations that would have the same issue all the way through market close. Here’s one way you could do that:

1. Let coin A be heads with probability 60%. This is public information.
2. Let coin B be an ALWAYS HEADS coin with probability 59% and ALWAYS TAILS coin with probability 41%. This is a secret.
3. Every day, generate a random integer between 1 and 30.
   1. If it’s 1, immediately resolve the markets.
   2. It it’s 2, reveal the nature of coin B.
   3. If it’s between 3 and 30, do nothing.

On average, this market will run for 30 days. (The length follows a geometric distribution). Half the time, the market will close without the nature of coin B being revealed. Even when that happens, I claim the price for coin B will still be above coin A.

If futarchy is flawed, shouldn’t you be able to show that without this weird step of “revealing” coin B?

Yes. You should be able to do that, and I think you can. Here’s one way:

1. Let coin A be heads with probability 60%. This is public information.
2. Sample 20 random bits, e.g. 10100011001100000001. Let coin B be heads with probability (49+N)% where N is the number of 1 bits. do not reveal these bits publicly.
3. Secretly send these bits to the first 20 people who ask.

openssl genrsa 1024 > private.pem
openssl rsa -in private.pem -pubout > public.pem

Hi, can you please send me a bit? Here's my public key:

-----BEGIN PUBLIC KEY-----
MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDOlesWS+mnvHJOD2osUkbrxE+Y
PMqAUYqwemOwML0LlWLq5RobZRSeyssQhg0i3g2GsMZFMsvjindz6mxccdyP4M8N
mQVCK1Ovs1Z4+DxwmLf/y8vaGC3vfZBOhJDdaNdpRyUiQFaBW99We4cafVnmirRN
Py2lRe+CFgP3kSp4dQIDAQAB
-----END PUBLIC KEY-----

I think this market captures a dynamic that’s present in basically any use of futarchy: You have some information, but you know other information is out there.

I claim that this market—will be weird. Say it just opened. If you didn’t get a bit, then as far as you know, the bias for coin B could be anywhere between 49% and 69%, with a mean of 59%. If you did get a bit, then it turns out that the posterior mean is 58.5% if you got a 0 and 59.5% if you got a 1. So either way, your best guess is very close to 59%.

However, the information for the true bias of coin B is out there! Surely coin B is more likely to end up with a higher price in situations where there are lots of 1 bits. This means you should bid at least a little higher than your true belief, for the same reason as the main experiment—the market activating is correlated with the true bias of coin B.

Of course, after the markets open, people will see each other’s bids and… something will happen. Initially, I think prices will be strongly biased for the above reasons. But as you get closer to market close, there’s less time for information to spread. If you are the last person to trade, and you know you’re the last person to trade, then you should do so based on your true beliefs.

Except, everyone knows that there’s less time for information to spread. So while you are waiting till the last minute to reveal your true beliefs, everyone else will do the same thing. So maybe people sort of rush in at the last second? (It would be easier to think about this if implemented with batched auctions rather than a real-time market.)

Anyway, while the game theory is vexing, I think there’s a mix of (1) people bidding higher than their true beliefs due to correlations between the final price and the true bias of coin B and (2) people “racing” to make the final bid before the markets close. Both of these seem in conflict with the idea of prediction markets making people share information and measuring collective beliefs.

Why do you hate futarchy?

I like futarchy. I think society doesn’t make decisions very well, and I think we should give much more attention to new ideas like futarchy that might help us do better. I just think we should be aware of its imperfections and consider variants (e.g. commiting to randomization) that would resolve them.

If I claim futarchy does reflect causal effects, and I reject this experiment as invalid, should I specify what restrictions I want to place on “valid” experiments (and thus make explicit the assumptions under which I claim futarchy works) since otherwise my claims are unfalsifiable?

Possibly?

2025-08-07 08:00:00

The heritability wars have been a-raging. Watching these, I couldn’t help but notice that there’s near-universal confusion about what “heritable” means. Partly, that’s because it’s a subtle concept. But it also seems relevant that almost all explanations of heritability are very, very confusing. For example, here’s Wikipedia’s definition:

Any particular phenotype can be modeled as the sum of genetic and environmental effects:

   Phenotype (P) = Genotype (G) + Environment (E).

Likewise the phenotypic variance in the trait – Var (P) – is the sum of effects as follows:

   Var(P) = Var(G) + Var(E) + 2 Cov(G,E).

In a planned experiment Cov(G,E) can be controlled and held at 0. In this case, heritability, H², is defined as

   H² = Var(G) / Var(P)

H² is the broad-sense heritability.

Do you find that helpful? I hope not, because it’s a mishmash of undefined terminology, unnecessary equations, and borderline-false statements. If you’re in the mood for a mini-polemic:

1. Phenotype (P) is never defined. This is a minor issue, since it just means “trait”.
2. Genotype (G) is never defined. This is a huge issue, since it’s very tricky and heritability makes no sense without it.
3. Environment (E) is never defined. This is worse than it seems, since in heritability, different people use “environment” and E to refer to different things.
4. When we write P = G + E, are we assuming some kind of linear interaction? The text implies not, but why? What does this equation mean? If this equation is always true, then why do people often add other stuff like G × E on the right?
5. The text states that if you do a planned experiment (how?) and make Cov(G, E) = 0, then heritability is Var(G) / Var(P). But in fact, heritability is always defined that way. You don’t need a planned experiment and it’s fine if Cov(G, E) ≠ 0.
6. And—wait a second—that definition doesn’t refer to environmental effects at all. So what was the point of introducing them? What was the point of writing P = G + E? What are we doing?

Reading this almost does more harm than good. While the final definition is correct, it never even attempts to explain what G and P are, it gives an incorrect condition for when the definition applies, and instead mostly devotes itself to an unnecessary digression about environmental effects. The rest of the page doesn’t get much better. Despite being 6700 words long, I think it would be impossible to understand heritability simply by reading it.

Meanwhile, some people argue that heritability is meaningless for human traits like intelligence or income or personality. They claim that those traits are the product of complex interactions between genes and the environment and it’s impossible to disentangle the two. These arguments have always struck me as “suspiciously convenient”. I figured that the people making them couldn’t cope with the hard reality that genes are very important and have an enormous influence on what we are.

But I increasingly feel that the skeptics have a point. While I think it’s a fact that most human traits are substantially heritable, it’s also true the technical definition of heritability is really weird, and simply does not mean what most people think it means.

In this post, I will explain exactly what heritability is, while assuming no background. I will skip everything that can be skipped but—unlike most explanations—I will not skip things that can’t be skipped. Then I’ll go through a series of puzzles demonstrating just how strange heritability is.

What is heritability?

How tall you are depends on your genes, but also on what you eat, what diseases you got as a child, and how much gravity there is on your home planet. And all those things interact. How do you take all that complexity and reduce it to a single number, like “80% heritable”?

The short answer is: Statistical brute force. The long answer is: Read the rest of this post.

It turns out that the hard part of heritability isn’t heritability. Lurking in the background is a slippery concept known as a genotypic value. Discussions of heritability often skim past these. Quite possibly, just looking at the words “genotypic value”, you are thinking about skimming ahead right now. Resist that urge! Genotypic values are the core concept, and without them you cannot possibly understand heritability.

For any trait, your genotypic value is the “typical” outcome if someone with your DNA were raised in many different random environments. In principle, if you wanted to know your genotypic height, you’d need to do this:

1. Create a million embryonic clones of yourself.
2. Implant them in the wombs of randomly chosen women around the world who were about to get pregnant on their own.
3. Convince them to raise those babies exactly like a baby of their own.
4. Wait 25 years, find all your clones and take their average height.

Since you can’t / shouldn’t do that, you’ll never know your genotypic height. But that’s how it’s defined in principle—the average height someone with your DNA would grow to in a random environment. If you got lots of food and medical care as a child, your actual height is probably above your genotypic height. If you suffered from rickets, your actual height is probably lower than your genotypic height.

Comfortable with genotypic values? OK. Then (broad-sense) heritability is easy. It’s the ratio

   heritability = var[genotype] / var[height].

Here, var is the variance, basically just how much things vary in the population. Among all adults worldwide, var[height] is around 50 cm². (Incidentally, did you know that variance was invented for the purpose of defining heritability?)

Meanwhile, var[genotype] is how much genotypic height varies in the population. That might seem hopeless to estimate, given that we don’t know anyone’s genotypic height. But it turns out that we can still estimate the variance using, e.g., pairs of adopted twins, and it’s thought to be around 40 cm². If we use those numbers, the heritability of height would be

   heritability ≈ (40 cm²) / (50 cm²) ≈ 0.8.

People often convert this to a percentage and say “height is 80% heritable”. I’m not sure I like that, since it masks heritability’s true nature as a ratio. But everyone does it, so I’ll do it too. People who really want to be intimidating might also say, “genes explain 80% of the variance in height”.

Of course, basically the same definition works for any trait, like weight or income or fondness for pseudonymous existential angst science blogs. But instead of replacing “height” with “trait”, biologists have invented the ultra-fancy word “phenotype” and write

   heritability = var[genotype] / var[phenotype].

The word “phenotype” suggests some magical concept that would take years of study to understand. But don’t be intimidated. It just means the actual observed value of some trait(s). You can measure your phenotypic height with a tape measure.

On meaning

Let me make two points before moving on.

First, this definition of heritability assumes nothing. We are not assuming that genes are independent of the environment or that “genotypic effects” combine linearly with “environmental effects”. We are not assuming that genes are in Hardy-Weinberg equilibrium, whatever that is. No. I didn’t talk about that stuff because I don’t need to. There are no hidden assumptions. The above definition always works.

Second, many normal English words have parallel technical meanings, such as “field”, “insulator”, “phase”, “measure”, “tree”, or “stack”. Those are all nice, because they’re evocative and it’s almost always clear from context which meaning is intended. But sometimes, scientists redefine existing words to mean something technical that overlaps but also contradicts the normal meaning, as in “salt”, “glass”, “normal”, “berry”, or “nut”. These all cause confusion, but “heritability” must be the most egregious case in all of science.

Before you ever heard the technical definition of heritability, you surely had some fuzzy concept in your mind. Personally, I thought of heritability as meaning how many “points” you get from genes versus the environment. If charisma was 60% heritable, I pictured each person has having 10 total “charisma points”, 6 of which come from genes, and 4 from the environment:

  Genes       ★★★☆☆☆
  Environment ★☆☆☆
  Total       ★★★★☆☆☆☆☆☆

If you take nothing else from this post, please remember that the technical definition of heritability does not work like that. You might hope that if we add some plausible assumptions, the above ratio-based definition would simplify into something nice and natural, that aligns with what “heritability” means in normal English. But that does not happen. If that’s confusing, well, it’s not my fault.

Intermission

Not sure what’s happening here, but it seems relevant.

Heritability puzzles

So “heritability” is just the ratio of genotypic and phenotypic variance. Is that so bad?

I think… maybe?

How heritable is eye color?

Close to 100%.

This seems obvious, but let’s justify it using our definition that heritability = var[genotype] / var[phenotype].

Well, people have the same eye color, no matter what environment they are raised in. That means that genotypic eye color and phenotypic eye color are the same thing. So they have the same variance, and the ratio is 1. Nothing tricky here.

How heritable is speaking Turkish?

Close to 0%.

Your native language is determined by your environment. If you grow up in a family that speaks Turkish, you speak Turkish. Genes don’t matter.

Of course, there are lots of genes that are correlated with speaking Turkish, since Turks are not, genetically speaking, a random sample of the global population. But that doesn’t matter, because if you put Turkish babies in Korean households, they speak Korean. Genotypic values are defined by what happens in a random environment, which breaks the correlation between speaking Turkish and having Turkish genes.

Since 1.1% of humans speak Turkish, the genotypic value for speaking Turkish is around 0.011 for everyone, no matter their DNA. Since that’s basically constant, the genotypic variance is near zero, and heritability is near zero.

How heritable is speaking English?

Perhaps 30%. Probably somewhere between 10% and 50%. Definitely more than zero.

That’s right. Turkish isn’t heritable but English is. Yes it is. If you ask an LLM, it will tell you that the heritability of English is zero. But the LLM is wrong and I am right.

Why? Let me first acknowledge that Turkish is a little bit heritable. For one thing, some people have genes that make them non-verbal. And there’s surely some genetic basis for being a crazy polyglot that learns many languages for fun. But speaking Turkish as a second language is quite rare, meaning that the genotypic value of speaking Turkish is close to 0.011 for almost everyone.

English is different. While only 1 in 20 people in the world speak English as a first language, 1 in 7 learn it as a second language. And who does that? Educated people.

Say there’s an island where genes have no impact on height. How heritable is height among people on this island?

0%.

There’s nothing tricky here.

Say there’s an island where genes entirely determine height. How heritable is height?

100%.

Again, nothing tricky.

Say there’s an island where neither genes nor the environment influence height and everyone is exactly 165 cm tall. How heritable is height?

It’s undefined.

In this case, everyone has exactly the same phenotypic and genotypic height, namely 165 cm. Since those are both constant, their variance is zero and heritability is zero divided by zero. That’s meaningless.

Say there’s an island where some people have genes that predispose them to be taller than others. But the island is ruled by a cruel despot who denies food to children with taller genes, so that on average, everyone is 165 ± 5 cm tall. How heritable is height?

0%.

On this island, everyone has a genotypic height of 165 cm. So genotypic variance is zero, but phenotypic variance is positive, due to the ± 5 cm random variation. So heritability is zero divided by some positive number.

Say there’s an island where some people have genes that predispose them to be tall and some have genes that predispose them to be short. But, the same genes that make you tall also make you semi-starve your children, so in practice everyone is exactly 165 cm tall. How heritable is height?

∞%. Not 100%, mind you, infinitely heritable.

To see why, note that if babies with short/tall genes are adopted by parents with short/tall genes, there are four possible cases.

If a baby with short genes is adopted into random families, they will be shorter on average than if a baby with tall genes. So genotypic height varies. However, in reality, everyone is the same height, so phenotypic height is constant. So genotypic variance is positive while phenotypic variance is zero. Thus, heritability is some positive number divided by zero, i.e. infinity.

(Are you worried that humans are “diploid”, with two genes (alleles) at each locus, one from each biological parent? Or that when there are multiple parents, they all tend to have thoughts on the merits of semi-starvation? If so, please pretend people on this island reproduce asexually. Or, if you like, pretend that there’s strong assortative mating so that everyone either has all-short or all-tall genes and only breeds with similar people. Also, don’t fight the hypothetical.)

Say there are two islands. They all live the same way and have the same gene pool, except people on island A have some gene that makes them grow to be 150 ± 5 cm tall, while on island B they have a gene that makes them grow to be 160 ± 5 cm tall. How heritable is height?

It’s 0% for island A and 0% for island B, and 50% for the two islands together.

Why? Well on island A, everyone has the same genotypic height, namely 150 cm. Since that’s constant, genotypic variance is zero. Meanwhile, phenotypic height varies a bit, so phenotypic variance is positive. Thus, heritability is zero.

For similar reasons, heritability is zero on island B.

But if you put the two islands together, half of people have a genotypic height of 150 cm and half have a genotypic height of 160 cm, so suddenly (via math) genotypic variance is 25 cm². There’s some extra random variation so (via more math) phenotypic variance turns out to be 50 cm². So heritability is 25 / 50 = 50%.

Var[150 cm + 10 cm × Bernoulli(0.5)]
 = (10 cm)² × Var[Bernoulli(0.5)]
 = (10 cm)² × 0.25
 = 25 cm².

Var[150 cm + 10 cm × Bernoulli(0.5) + 5 cm × Normal(0,1)]
 = (10 cm)² × Var[Bernoulli(0.5)] + (5 cm)² × Var[Normal(0,1)]
 = (10 cm)² × 0.25 + (5 cm)² × 1
 = 50 cm².

Say there’s an island where neither genes nor the environment influence height. Except, some people have a gene that makes them inject their babies with human growth hormone, which makes them 5 cm taller. How heritable is height?

0%.

True, people with that gene will tend be taller. And the gene is causing them to be taller. But if babies are adopted into random families, it’s the genes of the parents that determine if they get injected or not. So everyone has the same genotypic height, genotypic variance is zero, and heritability is zero.

Suppose there’s an island where neither genes nor the environment influence height. Except, some people have a gene that makes them, as babies, talk their parents into injecting them with human growth hormone. The babies are very persuasive. How heritable is height?

We’re back to 100%.

The difference with the previous scenario is that now babies with that gene get injected with human growth hormone no matter who their parents are. Since nothing else influences height, genotype and phenotype are the same, have the same variance, and heritability is 100%.

Suppose there’s an island where neither genes nor the environment influence height. Except, there are crabs that seek out blue-eyed babies and inject them with human growth hormone. The crabs, they are unstoppable. How heritable is height?

Again, 100%.

Babies with DNA for blue eyes get injected. Babies without DNA for blue eyes don’t. Since nothing else influences height, genotype and phenotype are the same and heritability is 100%.

Note that if the crabs were seeking out parents with blue eyes and then injecting their babies, then height would be 0% heritable.

It doesn’t matter that human growth hormone is weird thing that’s coming from outside the baby. It doesn’t matter if we think crabs should be semantically classified as part of “the environment”. It doesn’t matter that heritability would drop to zero if you killed all the crabs, or that the direct causal effect of the relevant genes has nothing to do with height. Heritability is a ratio and doesn’t care.

What good is heritability?

So heritability can be high even when genes have no direct causal effect on the trait in question. It can be low even when there is a strong direct effect. It changes when the environment changes. It even changes based on how you group people together. It can be larger than 100% or even undefined.

Even so, I’m worried people might interpret this post as a long way of saying heritability is dumb and bad, trolololol. So I thought I’d mention that this is not my view.

Say a bunch of companies create different LLMs and train them on different datasets. Some of the resulting LLMs are better at writing fiction than others. Now I ask you, “What percentage of the difference in fiction writing performance is due to the base model code, rather than the datasets or the GPUs or the learning rate schedules?”

That’s a natural question. But if you put it to an AI expert, I bet you’ll get a funny look. You need code and data and GPUs to make an LLM. None of those things can write fiction by themselves. Experts would prefer to think about one change at a time: Given this model, changing the dataset in this way changes fiction writing performance this much.

Similarly, for humans, I think what we really care about is interventions. If we changed this gene, could we eliminate a disease? If we educate children differently, can we make them healthier and happier? No single number can possibly contain all that information.

But heritability is something. I think of it as saying how much hope we have to find an intervention by looking at changes in current genes or current environments.

1. If heritability is high, then given current typical genes, you can’t influence the trait much through current typical environmental changes. If you only knew that eye color was 100% heritable, that means you won’t change your kid’s eye color by reading to them, or putting them on a vegetarian diet, or moving to higher altitude. But it’s conceivable you could do it by putting electromagnets under their bed or forcing them to communicate in interpretive dance.

2. If heritability is high, that also means that given current typical environments you can influence the trait through current typical genes. If the world was ruled by an evil despot who forced red-haired people to take pancreatic cancer pills, then pancreatic cancer would be highly heritable. And you could change the odds someone gets pancreatic cancer by swapping in existing genes for black hair.

3. If heritability is low, that means that given current typical environments, you can’t cause much difference through current typical genetic changes. If we only knew that speaking Turkish was ~0% heritable, that means that doing embryo selection won’t much change the odds that your kid speaks Turkish.

4. If heritability is low, that also means that given current typical genes, you might be able change the trait through current typical environmental changes. If we only know that speaking Turkish was 0% heritable, then that means there might be something you could do to change the odds your kid speaks Turkish, e.g. moving to Turkey. Or, it’s conceivable that it’s just random and moving to Turkey wouldn’t do anything.

But be careful. Just because heritability is high doesn’t mean that changing genes is easy. And just because heritability is low doesn’t mean that changing the environment is easy.

And heritability doesn’t say anything about non-typical environments or non-typical genes.

If an evil despot is giving all the red-haired people cancer pills, perhaps we could solve that by intervening on the despot. And if you want your kid to speak Turkish, it’s possible that there’s some crazy genetic modifications that would turn them into unstoppable Turkish learning machine.

Heritability has no idea about any of that, because it’s just an observational statistic based on the world as it exists today.

Recommended reading

• Heritability: Five Battles by Steven Byrnes. Covers similar issues in way that’s more connected to the world and less shy about making empirical claims.

• A molecular genetics perspective on the heritability of human behavior and group differences by Alexander Gusev. I find the quantitative genetics literature to be incredibly sloppy about notation and definitions and math. (Is this why LLMs are so bad at it?) This is the only source I’ve found that didn’t drive me completely insane.

Appendix

2025-07-17 08:00:00

1.

Your eyes sense color. They do this because you have three different kinds of cone cells on your retinas, which are sensitive to different wavelengths of light.

For whatever reason, evolution decided those wavelengths should be overlapping. For example, M cones are most sensitive to 535 nm light, while L cones are most sensitive to 560 nm light. But M cones are still stimulated quite a lot by 560 nm light—around 80% of maximum. This means you never (normally) get to experience having just one type of cone firing.

So what do you do?

If you’re a quitter, I guess you accept the limits of biology. But if you like fun, then what you do is image people’s retinas, classify individual cones, and then selectively stimulate them using laser pulses, so you aren’t limited by stupid cone cells and their stupid blurry responsivity spectra.

Fong et al. (2025) choose fun.

When they stimulated only M cells…

Subjects report that [pure M-cell activation] appears blue-green of unprecedented saturation.

If you make people see brand-new colors, you will have my full attention. It doesn’t hurt to use lasers. I will read every report from every subject. Do our brains even know how to interpret these signals, given that they can never occur?

But tragically, the paper doesn’t give any subject reports. Even though most of the subjects were, umm, authors on the paper. If you want to know what this new color is like, the above quote is all you get for now.

2.

Or… possibly you can see that color right now?

If you click on the above image, a little animation will open. Please do that now and stare at the tiny white dot. Weird stuff will happen, but stay focused on the dot. Blink if you must. It takes one minute and it’s probably best to experience it without extra information i.e. without reading past this sentence.

The idea for that animation is not new. It’s plagiarized based on Skytopia’s Eclipse of Titan optical illusion (h/t Steve Alexander), which dates back to at least 2010. Later I’ll show you some variants with other colors and give you a tool to make your own.

If you refused to look at the animation, it’s just a bluish-green background with a red circle on top that slowly shrinks down to nothing. That’s all. But as it shrinks, you should hallucinate a very intense blue-green color around the rim.

Why do you hallucinate that crazy color? I think the red circle saturates the hell out of your red-sensitive L cones. Ordinarily, the green frequencies in the background would stimulate both your green-sensitive M cones and your red-sensitive L cones, due to their overlapping spectra. But the red circle has desensitized your red cones, so you get to experience your M cones firing without your L cones firing as much, and voilà—insane color.

3.

So here’s my question: Can that type of optical illusion show you all the same colors you could see by shooting lasers into your eyes?

That turns out to be a tricky question. See, here’s a triangle:

Think of this triangle as representing all the “colors” you could conceivably experience. The lower-left corner represents only having your S cones firing, the top corner represents only your M cones firing, and so on.

So what happens if you look different wavelengths of light?

Short wavelengths near 400 nm mostly just stimulate the S cones, but also stimulate the others a little. Longer wavelengths stimulate the M cones more, but also stimulate the L cones, because the M and L cones have overlapping spectra. (That figure, and the following, are modified from Fong et al.)

When you mix different wavelengths of light, you mix the cell activations. So all the colors you can normally experience fall inside this shape:

That’s the standard human color gamut, in LMS colorspace. Note that the exact shape of this gamut is subject to debate. For one thing, the exact sensitivity of cells is hard to measure and still a subject of research. Also, it’s not clear how far that gamut should reach into the lower-left and lower-right corners, since wavelengths outside 400-700 nm still stimulate cells a tiny bit.

And it gets worse. Most of the technology we use to represent and display images electronically is based on standard RGB (sRGB) colorspace. This colorspace, by definition, cannot represent the full human color gamut.

The precise definition of sRGB colorspace is quite involved. But very roughly speaking, when an sRGB image is “pure blue”, your screen is supposed to show you a color that looks like 450-470 nm light, while “pure green” should look like 520-530 nm light, and “pure red” should look like 610-630 nm light. So when your screen mixes these together, you can only see colors inside this triangle.

(The corners of this triangle don’t quite touch the boundaries of the human color gamut. That’s because it’s very difficult to produce single wavelengths of light without using lasers. In reality, the sRGB specification say that pure red/blue/green should produce a mixture of colors centered around the wavelengths I listed above.)

What’s the point of all this theorizing? Simple: When you look at the optical illusions on a modern screen, you aren’t just fighting the overlapping spectra of your cones. You’re also fighting the fact that the screen you’re looking at can’t produce single wavelengths of light.

So do the illusions actually take you outside the natural human color gamut? Unfortunately, I’m not sure. I can’t find much quantitative information about how much your cones are saturated when you stare at red circles. My best guess is no, or perhaps just a little.

4.

If you’d like to explore these types of illusions further, I made a page in which you can pick any colors. You can also change the size of the circle, the countdown time, if the circle should shrink or grow, and how fast it does that.

You can try it here. You can export the animation to an animated SVG, which will be less than 1 kb. Or you can just save the URL.

Some favorites:

• Red inside, reddish-orange outside

• Red inside, green outside

• Green inside, purple outside

If you’re colorblind, I don’t think these will work, though I’m not sure. Folks with deuteranomaly have M cones, but they’re shifted to respond more like L cones. In principle, these types of illusions might help selectively activate them, but I have no idea if that will lead to stronger color perception. I’d love to hear from you if you try it.