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Crémieux Profile picture
Crémieux
@cremieuxrecueil
I write about genetics, 'metrics, and demographics. Read my long-form writing at https://t.co/8hgA4nNS2A.
49 subscribers
Dec 7 • 7 tweets • 3 min read
Why do identical twins have such similar personalities?

Is it because they're reared together? Is it because people treat them alike due to their visual similarity?

Nope! Neither theory holds water. Image Despite looking as similar as identical twins and being reared apart, look-alikes are not similar like identical twins are. In fact, they're no more similar than unrelated people.

This makes sense: they're only minimally more genetically similar than regular unrelated people.
Dec 2 • 5 tweets • 2 min read
Society is cognitively stratified:

Smart people tend to earn higher educations and higher incomes, and to work in more prestigious occupations.

This holds for people from excellent family backgrounds (Utopian Sample) and comparing siblings from the same families! Image This is true, meaningful, and the causal relationship runs strongly from IQ to SES, with little independent influence of SES. Just look at how similar the overall result and the within-family results are!

But also look at fertility in this table: quite the reverse! Image
Nov 25 • 10 tweets • 5 min read
After this article came out, several people responded, alleging that a cultural model made more sense.

Clark has a point-by-point response🧵

Let's start with the first thing: parent-child and sibling correlations in status measures are identical—hard to explain culturally! Image The reason this is hard to explain has to do with the fact that kids objectively have more similar environments to one another than to their parents.

In fact, for a cultural theory to recapitulate regression to the mean across generations, these things would need to differ! Image
Nov 24 • 4 tweets • 2 min read
The idea:

The internet gives everyone access to unlimited information, learning tools, and the new digital economy, so One Laptop Per Child should have major benefits.

The reality:

Another study just failed to find effects on academic performance. Image This is one of those findings that's so much more damning than it at first appears.

The reason being, laptop access genuinely provides people with more information than was available to any kid at any previous generation in history.

If access was the issue, this resolves it. Image
Nov 22 • 5 tweets • 2 min read
What is the effect of having a parent get locked away on a kids' own risk of eventually committing crime?

As it turns out, basically nil.

Having a mother or a father locked away doesn't significantly increase risk, and indeed, may reduce it if it happens at an early age. Image This is relative to no incarceration, so the result should be interpreted as... pretty shocking!

Similarly, we can look at the effects of longer versus shorter parental sentences.

There's seemingly little effect of the length of time parents are incarcerated for. Image
Nov 20 • 4 tweets • 2 min read
Why?

I doubt the answer is weight loss. Consider 2 other drugs for diabetes: DPP-4 and SGLT-2 inhibitors

GLP-1RAs are associated with less Alzheimer's vs. DPP-4is:

But not SGLT-2is:

Neither generates much weight loss, but SGLT-2is match GLP-1RAs on glycemic benefitsImage
Image So, at least in this propensity score- or age-matched data, there's no reason to chalk the benefit up to the weight loss effects.

This is a hint though, not definitive. Another hint is that benefits were observed in short trials, meaning likely before significant weight loss.
Nov 20 • 5 tweets • 2 min read
El Salvador is now a safe country

The reason why should teach us something about commitment

The government there has previously attempted crackdowns twice in the form of mano dura—hard hand—, but they failed because they didn't hit criminals hard enough

Then Bukele really didImage In fact, previous attempts backfired compared to periods in which the government made truces with the gangs.

The government cracking down a little bit actually appeared to make gangs angrier!

You'd have been in your right to conclude 'tough on crime fails', but you'd be wrong.
Nov 18 • 4 tweets • 2 min read
Diets that restrict carbohydrate consumption lead to improved blood sugar and insulin levels, as well as reduced insulin resistance.

Additionally, they're good or neutral for the liver and kidneys, and they don't affect the metabolic rate. Image Carbohydrate isn't the only thing that affects glycemic parameters.

So does fat!

So, for example, if you replace 5% of dietary calories from saturated fat with PUFA, that somewhat improves fasting glucose levels (shown), and directionally improves fasting insulin: Image
Nov 18 • 11 tweets • 6 min read
Property taxes should, in theory, make it so buying a home is more affordable and young people will have increased access to home ownership.

Let's look through the literature to see what really happens🧵

Firstly, higher property taxes get older people to move. Image Higher property taxes act as leverage since they're capitalized into house prices.

This reduces the number of people who own multiple homes, increases general ownership, and increases young ownership even more. Image
Nov 18 • 19 tweets • 7 min read
There's a popular belief that family wealth is gone in three generations.

The first earns it, the second stewards it, and the third spends it away: from shirtsleeves to shirtsleeves in three generations!

But how true is this belief?

Gregory Clark has new evidence🧵 Image The first thing to note is that family wealth is correlated across many generations. For example, in medieval England, this is how wealth at death correlates across six generations.

It correlates substantially enough to persist for twelve generations at observed rates of decay: Image
Nov 18 • 16 tweets • 6 min read
The Catholic Church helped to modernize the West due to its ban on cousin marriage and its disdain for adoption, but also by way of its opposition to polygyny.

The origin of this disdain arguably lies with Church Fathers like Justin Martyr, Irenaeus, and Tertullian🧵 Image Justin Martyr, in his Dialogue with Trypho argues with a Jew that Christians are the ones living in continuity with God's true intentions.

Justin sees Genesis 2 ("the two shall become one flesh") as normative.

In his apologetic world, Christians are supposed to transcend lust.Image
Nov 17 • 5 tweets • 2 min read
Neat!

This result replicates not only with trait transmission, but also with the social transmission of social status.

That is, the vast majority of the variance in social status is not derived from parents, and the part that is generally isn't direct. Different designs agree: Image This study also provided novel estimates using large-scale Norwegian data.

So, for example, their first design involved comparing regression coefficients for adoptees versus non-adoptees for each of the four major SES variables.

Replicating earlier studies, wealth was weak. Image
Nov 17 • 12 tweets • 6 min read
The effects of charter schools on student test scores are meta-analytically estimated to be small.

In this study, the largest estimated effect was estimated to be equivalent to ~1.35 IQ points, for mathematics scores, which consistently showed larger effects than reading scores. Image Similarly, the estimated effect of parents' preferred schools and of elite public secondary schools on test scores is around zero. Image
Nov 15 • 4 tweets • 2 min read
Married people tend to be at lower risk of dying compared to the unmarried.

Another thing is that men seem to benefit more from partnership than women do.

The difference in the benefit between men and women is driven by confounding and much of the total effect is too: Image I'm not sure what's left is causal, and it will be hard to figure that out. This is the sort of thing you'd need an econometric design for. You'd likely need to exploit something that changes the odds of partnership to truly really get at this.

Or get more twins and re-assess!
Nov 14 • 5 tweets • 2 min read
One of the reasons it is unwise to assume that the relationship between variables like household income and kids' IQ is causal is because society is meritocratic

Smart (dull) people tend to move up (down), and they'll transmit ability to their kids regardless of household income Image Meritocracy makes class confounded, and it shows that class is also not destiny, either

Thanks to modern genome-wide association studies, we now have molecular genetic evidence for genetic confounding

Consider these four cohorts: across them, polygenic scores predict mobility! Image
Nov 12 • 18 tweets • 6 min read
I'm blocked, so can't reply in thread, but the essay seems to be a mixture of:

- Goalpost moving
- Misrepresenting sources
- Not understanding what von Neumann worked on
- Overclaim
- Ignoring inconvenient facts
- Nothing relevant to his initial aristocratic education claims Scott Alexander is exactly correct about what Hoel is doing here:

He is "citing [von Neumann biographies] in a misleading, bordering on dishonest, way."

theintrinsicperspective.com/p/john-von-neu…
Nov 12 • 16 tweets • 5 min read
Amazing!

The missing heritability issue between SNP heritability methods and traditional pedigree-based estimates has now shrunken to just 12%.

Thanks to large-scale whole-genome data and simultaneously estimated phenotypes, there's not much missing heritability left! Image This analysis has several advantages compared to earlier ones.

The most obvious is the whole-genome data combined with a large sample size. All earlier whole-genome heritability estimates have been made using smaller samples, and thus had far greater uncertainty.
Nov 12 • 4 tweets • 2 min read
This policy change has resulted in liberal experts coming out of the woodwork to allege that the policy is...

Intended to discriminate against Hispanics and Indians!

This one even alleged that this is discrimination on the basis of genetic race differences!Image Trump deserves some praise for getting people to fess up to their hereditarian views on this matter.

Also, frankly, the policy is reasonable.

No fat people, no psychos, no sick people who will be burdens.

The only exception should be for those *paying for treatment here*. Image
Nov 8 • 21 tweets • 5 min read
Here are some choice Watson quotes to think about.

"I wouldn't have married a gum-chewing vegetarian." Image Just being correct: Image
Nov 8 • 18 tweets • 8 min read
I'm going to humbly request that everyone stop dunking on John when he isn't even wrong.

Firstly, the reason for the hollowed out middle between -1.96 and 1.96 (p = 0.05) is not due to calculating CIs from abstracts instead of full-texts.

The original source showed that!Image The original source for the Medline p-values explicitly compared the distributions in the abstracts and full-texts.

They found that there was a kink such that positive results had excess lower-bounds above 1 and negative results had excess upper-bounds below 1.Image
Nov 7 • 6 tweets • 2 min read
I got blocked for this meager bit of pushback on an obviously wrong idea lol.

Seriously:

Anyone claiming that von Neumann was tutored into being a genius is high on crack. He could recite the lines from any page of any book he ever read. That's not education! 'So, what's your theory on how von Neumann could tell you the exact weights and dimensions of objects without measuring tape or a scale?'

'Ah, it was the education that was provided to him, much like the education provided to his brothers and cousins.' Image