The Sweet Zone

You can think of the habitable zone as a region in a multidimensional parameter space on which members of a species do well enough to persist. Move them slowly towards the edge of the zone and they often adapt.  Move them too fast and they can’t, move them too far and they can’t.

Generally speaking, fitness declines as the environment gets farther from the one they’re adapted to.  But there is an important class of exceptions to this generalization.

Describe it.


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Dr. Paige Harden said “No scientific finding leads inexorably to any particular social policy”.  Well, it would if we were Pak: they have built-in goals and are almost always smart enough to see the best path leading to those goals, given circumstances.

The introduction of gunpowder favored some social changes – for one, centralization, because castles stopped working. You couldn’t fort up and wait out the King’s men anymore. It also favored everybody using gunpowder weapons, because they were more effective. But there was an exception: the Tokugawa Shogunate almost entirely gave up firearms. Obviously, this was possible in an isolated, tightly controlled Japan.  Surprisingly, unlikely, but possible.  Could the same thing have happened in early modern europe, composed of many competing states? Could they have given up the gun?

Not in a million years. The spread of firearms weapons in Europe was… inexorable.


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Shared environment

Seems to me that there’s an awful lot of overlap between the environmental factors in shared family environment and those that are supposed to explain group differences.

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Take my wife, please !

There’s a new paper out in Science – ” The genomic history of the Iberian Peninsula over the past 8000 years” .  It discusses genetic change over time, from hunter-gatherer days, the arrival of the Anatolian-ancestry farmers, and the coming of the Indo-Europeans.

The chart above shows what happened when the Indo-Europeans show up. Autosomal steppe ancestry goes from zero to ~40%, but on the Y-chromosome, it goes from zero to 100% over a few hundred years.  As quoted in the New York Times, archaeologists ruled out violence as a possible cause. [ ” I cannot say what it is,”said Roberto Risch, an archaeologist from the Autonomous University of Barcelona, who was not involved in the new studies/ But he ruled out wars or massacres as the cause. “It’s not a particularly violent time,”, he said.

Instead, Dr. Risch suspects “a political process” is the explanation. ]

For background: archaeologists have saying things like this for many years. They denied that there had been  major migrations and population replacements in prehistory [proven wildly wrong ]. They could find a Neolithic fort in England covered with scattered bone fragments and suggest that it must have been a place where bodies were exposed for excarnation, like the Parsee Towers of Silence.

They’re nuts.

To those who like the notion that the Indo-Europeans triumphed because they carried in bubonic plague ( or some other pathogen) that blasted immunologically naive EEF farmers: find me a plague that only kills men – all of them.

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selective immigration

Some cases involve stronger selection than I would have guessed.  Nigerian male immigrants to Great Britain, 1980-2010:

low, medium, and high level of education:  ” We distinguish three levels of education: primary (low skilled: includes lower secondary, primary and no schooling); secondary (medium-skilled: high-school leaving certificate or equivalent) and tertiary education (high-skilled: higher than high-school leaving certificate or equivalent).”

1980 3204 6926 1942
1985 4435 4606 4953

1990 5796 2484 7885

1995 7142 2132 3528

2000 8650 2484 22324

2005 7869 2540 26608

2010 9326 3406 42106

Nigeria graduates about  150,000 people a year, so something like 2% of modern Nigerians graduate from college.


P.S. Suppose you only took the top few percent from a population with a low average: you might end up with a mean IQ of 100, but there would be a funny distribution.  Not much of a right tail.





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Someone on the internet was saying that  “genetically engineering babies for intelligence etc. probably wouldn’t work. All of our associations are inextricably and unknowably culture-bound (both wrt to time & place)”  If I have this right, just because certain genetic variants were associated with higher intelligence in a  given place and time (say Budapest, 1900), that doesn’t mean that those associations would hold the day after tomorrow.  An equivalent statement:  just because John Von Neumann was smart, that doesn’t mean that his clone, conceived in 2019, would be a sharp cookie  on maturity.  Perhaps the current shortage of Gemütlichkeit, or missing out on the stimulating effect of the Bela Kun regime,  would derail the clone’s proper development.

One can imagine ways in which something like this could come about. Suppose that some existing population averaged high scores on mental rotation, but that, 20 years from now, everyone has a little doodad that plugs directly into your brain and makes you far better at spatial visualization  (in N dimensions!) than anyone alive today. Those alleles would go from advantageous today to useless tomorrow.  Or, if there’s an outbreak of the zombie virus, everybody becomes a zombie.  Zombies are known to be deficient in spatial visualization.

So the claim is logically possible.  Do I think there’s much chance that it’s true: that increasing the number of plus variants ( as determined by GWAS) by genetic engineering or genetically informed selection would fail, because you can never step into the same environment twice?  The same reason that hybrid corn strains only work in the field where they were developed?

No. I think it’s total bullshit.




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Assortative Mating

If memory serves, both of Bruce Lahn’s parents were physicists. I believe they met while working in a coal mine.

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