loader from loading.io

Missing Heritability: Much More Than You Wanted To Know

Astral Codex Ten Podcast

Release Date: 07/01/2025

Apply For An ACX Grant (2025) show art Apply For An ACX Grant (2025)

Astral Codex Ten Podcast

We’re running another ACX Grants round! If you already know what this is and just want to apply for a grant, use (should take 15 - 30 minutes), deadline August 15. If you already know what this is and want to help as a , , , , or , click the link for the relevant form, same deadline. Otherwise see below for more information. What is ACX Grants? ACX Grants is a microgrants program that helps fund ACX readers’ charitable or scientific projects. Click the links to see the and cohorts. The program is conducted in partnership with , a charity spinoff of Manifold Markets, who handle the...

info_outline
Press Any Key For Bay Area House Party show art Press Any Key For Bay Area House Party

Astral Codex Ten Podcast

[previously in series: , , , , , ] It is eerily silent in San Francisco tonight. Since Mayor Lurie's crackdown, the usual drug hawkers, catcallers, and street beggars are nowhere to be seen. Still, your luck can’t last forever, and just before you reach your destination a man with bloodshot eyes lurches towards you. You recognize him and sigh. "Go away!" you shout. "Hey man," says Mark Zuckerberg, grabbing your wrist. "You wanna come build superintelligence at Meta? I'll give you five million, all cash." "I said go away!" "Ten million plus a Lambo," he counters. "I don't even know anything...

info_outline
Your Review: Islamic Geometric Patterns In The Metropolitan Museum Of Art show art Your Review: Islamic Geometric Patterns In The Metropolitan Museum Of Art

Astral Codex Ten Podcast

[This is one of the finalists in the 2025 review contest, written by an ACX reader who will remain anonymous until after voting is done. I’ll be posting about one of these a week for several months. When you’ve read them all, I’ll ask you to vote for a favorite, so remember which ones you liked]

info_outline
Book Review: Arguments About Aborigines show art Book Review: Arguments About Aborigines

Astral Codex Ten Podcast

I. A thought I had throughout reading L.R. Hiatt’s was: What are anthropologists even doing? The book recounts two centuries’ worth of scholarly disputes over questions like whether aboriginal tribes had chiefs. But during those centuries, many Aborigines learned English, many Westerners learned Aboriginal languages, and representatives of each side often spent years embedded in one another’s culture. What stopped some Westerner from approaching an Aborigine, asking “So, do you have chiefs?” and resolving a hundred years of bitter academic debate? Of course the answer must be...

info_outline
Your Review: Of Mice, Mechanisms, and Dementia show art Your Review: Of Mice, Mechanisms, and Dementia

Astral Codex Ten Podcast

[This is one of the finalists in the 2025 review contest, written by an ACX reader who will remain anonymous until after voting is done. I’ll be posting about one of these a week for several months. When you’ve read them all, I’ll ask you to vote for a favorite, so remember which ones you liked] “The scientific paper is a ‘’ that creates “a totally misleading narrative of the processes of thought that go into the making of scientific discoveries.” This critique comes not from a conspiracist on the margins of science, but from Nobel laureate Sir Peter Medawar. A brilliant...

info_outline
Practically-A-Book Review: Byrnes on Trance show art Practically-A-Book Review: Byrnes on Trance

Astral Codex Ten Podcast

Steven Byrnes is a physicist/AI researcher/amateur neuroscientist; needless to say, he blogs on Less Wrong. I finally got around to reading . If that sounds boring, it shouldn’t: Byrnes charges head-on into some of the toughest subjects in psychology, including trance, amnesia, and multiple personalities. I found his perspective enlightening (no pun intended; meditation is another one of his topics) and thought I would share. It all centers around this picture: But first: some excruciatingly obvious philosophical preliminaries.  

info_outline
Now I Really Won That AI Bet show art Now I Really Won That AI Bet

Astral Codex Ten Podcast

  In June 2022, I bet a commenter $100 that AI would master image compositionality by June 2025. DALL-E2 had just come out, showcasing the potential of AI art. But it couldn’t follow complex instructions; its images only matched the “vibe” of the prompt. For example, here were some of its attempts at “a red sphere on a blue cube, with a yellow pyramid on the right, all on top of a green table”. At the time, I wrote: I’m not going to make the mistake of saying these problems are inherent to AI art. My guess is a slightly better language model would solve most of them…for...

info_outline
Your Review: School show art Your Review: School

Astral Codex Ten Podcast

[This is one of the finalists in the 2025 review contest, written by an ACX reader who will remain anonymous until after voting is done. It was originally given an Honorable Mention, but since was about an exciting new experimental school, I decided to promote this more conservative review as a counterpoint.] “Democracy is the worst form of Government except for all those other forms that have been tried from time to time.” - Winston Churchill “There exists in such a case a certain institution or law; let us say, for the sake of simplicity, a fence or gate erected across a road. The...

info_outline
Highlights From The Comments On Missing Heritability show art Highlights From The Comments On Missing Heritability

Astral Codex Ten Podcast

[Original thread here: ] 1: Comments From People Named In The Post 2: Very Long Comments From Other Very Knowledgeable People 3: Small But Important Corrections 4: Other Comments

info_outline
Links For July 2025 show art Links For July 2025

Astral Codex Ten Podcast

[I haven’t independently verified each link. On average, commenters will end up spotting evidence that around two or three of the links in each links post are wrong or misleading. I correct these as I see them, and will highlight important corrections later, but I can’t guarantee I will have caught them all by the time you read this.]

info_outline
 
More Episodes

The Story So Far

The mid-20th century was the golden age of nurture. Psychoanalysis, behaviorism, and the spirit of the ‘60s convinced most experts that parents, peers, and propaganda were the most important causes of adult personality.

Starting in the 1970s, the pendulum swung the other way. Twin studies shocked the world by demonstrating that most behavioral traits - especially socially relevant traits like IQ - were substantially genetic. Typical estimates for adult IQ found it was about 60% genetic, 40% unpredictable, and barely related at all to parenting or family environment.

By the early 2000s, genetic science reached a point where scientists could start pinpointing the particular genes behind any given trait. Early candidate gene studies, which hoped to find single genes with substantial contributions to IQ, depression, or crime, mostly failed. They were replaced with genome wide association studies, which accepted that most interesting traits were polygenic - controlled by hundreds or thousands of genes - and trawled the whole genome searching for variants that might explain 0.1% or even 0.01% of the pie. The goal shifted toward polygenic scores - algorithms that accepted thousands of genes as input and spit out predictions of IQ, heart disease risk, or some other outcome of interest.

The failed candidate gene studies had sample sizes in the three or four digits. The new genome-wide studies needed five or six digits to even get started. It was prohibitively difficult for individual studies to gather so many subjects, genotype them, and test them for the outcome of interest, so work shifted to big centralized genome repositories - most of all the UK Biobank - and easy-to-measure traits. Among the easiest of all was educational attainment (EA), ie how far someone had gotten in school. Were they a high school dropout? A PhD? Somewhere in between? This correlated with all the spicy outcomes of interest people wanted to debate - IQ, wealth, social class - while being objective and easy to ask about on a survey.

Twin studies suggested that IQ was about 60% genetic, and EA about 40%. This seemed to make sense at the time - how far someone gets in school depends partly on their intelligence, but partly on fuzzier social factors like class / culture / parenting. The first genome-wide studies and polygenic scores found enough genes to explain 2%pp1 of this 40% pie. The remaining 38%, which twin studies deemed genetic but where researchers couldn’t find the genes - became known as “the missing heritability” or “the heritability gap”.

Scientists came up with two hypothesis for the gap, which have been dueling ever since:

  1. Maybe twin studies are wrong.
  2. Maybe there are genes we haven’t found yet

For most of the 2010s, hypothesis 2 looked pretty good. Researchers gradually gathered bigger and bigger sample sizes, and found more and more of the missing heritability. A big 2018 study increased the predictive power of known genes from 2% to 10%. An even bigger 2022 study increased it to 14%, and current state of the art is around 17%. Seems like it was sample size after all! Once the samples get big enough we’ll reach 40% and finally close the gap, right?

This post is the story of how that didn’t happen, of the people trying to rehabilitate the twin-studies-are-wrong hypothesis, and of the current status of the debate. Its most important influence/foil is Sasha Gusev, whose blog The Infintesimal introduced me to the new anti-hereditarian movement and got me to research it further, but it’s also inspired by Eric Turkheimer, Alex Young (not himself an anti-hereditarian, but his research helped ignite interest in this area), and Awais Aftab.

(while I was working on this draft, the East Hunter Substack wrote a similar post. Theirs is good and I recommend it, but I think this one adds enough that I’m publishing anyway)

https://www.astralcodexten.com/p/missing-heritability-much-more-than