The Mating Mind

Do women find high  intelligence attractive?  Apparently not (MALE GENERAL INTELLIGENCE (G) DOES NOT INCREASE FEMALE SEXUAL ATTRACTION), as discussed on James Thompson’s blog.  I think I already knew this, to the extent that I thought Geoffrey Miller’s book on the subject a barrel of crazy.

I’m pretty sure that, on average, men don’t find intelligence attractive in women, either.  Although a few do (like me).

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The Wrong Guys

The social sciences have developed in ways that are not necessarily to our advantage. How to fix?

Jonathan Haidt thinks that social psychology has problems (I might put it a bit more strongly) that might be ameliorated by adding ideological diversity – Republicans or Jacobites or whatever.

Personally, I doubt it.  I don’t think that the guys who produce all those unreplicable results were driven by the search for that Eureka moment when you finally figure it out, finally see it clearly.  I don’t think it’s really a product of people with the right motives whose statistics are sloppy, which we do see in some other fields and can sometimes fix.

I think they’re just no damn good.




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Greg is back home

Ruth writes that Greg is home from the hospital. He is still quite uncomfortable I gather but progressing rapidly. He will soon be berating all of us again.

Toddy Cat asked me for a post in Greg’s absence. I will try to bang one out tomorrow, part II of my fantasy about a knowledge-based public welfare system.

I have to apologize for my recent absence of posts here. I have had my own struggle with health this past year, which I find mildly interesting. Because of recurrent atrial fibrillation I was given a new anticoagulant. As an apparent outcome I had a brain bleed while in Germany. I was completely unaware of it at the time since the only symptom I experience was an inability to read. The bleed was in my left temporal lobe right at an area of the brain that is dedicated to reading in humans. Why on earth we have a dedicated reading area is a mystery to me.

I arrived in Germany, got some sleep, then went walking for hours around Munich: I always do this to nudge my circadian rhythms after international flight. With no knowledge of the German language, I walked for hours completely unaware that I could not parse written words. Then I gave a talk for an hour and half at the University with no discernible impairment, neither to anyone in the audience nor to myself. After dinner I found that I could see the letters in my email but could make no sense at all of them. Interestingly I had had no trouble reading my own slides during the talk.

I seem to have mostly recovered but I make a lot of typing errors and my prose is still full of bad spelling and typos. My balance also seems slight affected but at my age that is perhaps no surprise.

So I will write something tomorrow but you all will have to agree not to laugh at my spelling errors and errors of grammar.

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Things are going to be slow for a while, because I’ll be recovering from bypass surgery (happens tomorrow).



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Something else

Razib has talked about this – here’s what I think.

The various sweeping alleles that have made Europeans and North Asians have light skin  were not favored because they helped you garner extra vitamin D, at least not mostly. This is apparent from the allelic structure.  There is a single sweeping variant for SLC24A5: if paleness was the point, many partial loss-of-function alleles would be favored, rather like what we see with G6PD deficiency (a malaria defense).  But there is only one: so loss of function is not the point (or at least not the sole point): that particular variant has some other advantage, a big one.  The fact that it’s favored up on the Ethiopian plateau is another sign that it isn’t driven by vitamin D. There is only one blue-eye mutation (OCA2), only one main blond mutation (KITLG). The SLC24A5 mutation has by far the largest effect on skin color – if it isn’t being selected for paleness,  the  sweeping alleles of other coloration genes aren’t either.  Probably not even MC1R – it has many common loss-of-function mutations, which implies that loss of function is favored – but probably not because of the paleness. Something else.

If you’re close enough to the equator, you need dark skin, and the genes in these pathways are constrained – not free to change. But if they are free to change, then a change that improves fitness through a pleiotropic effect is now free to spread, since the resulting paleness is bearable. In many cases that would require a specific change, not just loss of function  – so we see an allelic structure unlike that of G6PD.

The same is likely the case with the various sweeping skin-color alleles in East Asia (although they are less colorful).

So we need to figure out what useful thing  these mutations actually do.  Dropping the vitamin D hypothesis raises lots of questions.

Posted in Genetics, Skin color | 98 Comments

Infertilty Belt

Infertility Belt

It used to be the case (considerably less so today) that a significant fraction of women in central Africa, up to tens of percent in some areas, were infertile or subfertile, due to various STDs.  This seems to have been true for quite a while, up until the 1990s and back some indefinite amount of time, probably at least one or two centuries.  It might be older than that, but at this point nobody knows.  There was enough infertility that colonial administrators worried about keeping up the population, in the days before readily available antibiotics:  for example, the population of Gabon seems to have decreased between 1930 and 1950.

Most of this infertility was caused through  tubal scarring caused by gonorrhea and chlamydal infections.

If this pattern was around long enough, there could have been significant selection for resistance to the relevant pathogens, possibly generating high frequencies of alleles with odd or unpleasant side effects, as with  malaria and sickle-cell/thalassemia etc.  This would depend on the age of the behavior patterns that made this possible, on the antiquity of  the pathogens causing those STDs, etc.





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TLRs, PAMPs, and Alley Oop

I hear that some Eurasians  – probably more than some – have Neanderthal or Denisovan versions of TLRs.  Not surprising: we’ve already seen this happen with other immune system genes – HLA variants , OAS1, STAT2  all have adaptive variants that originated with archaic humans.

TLRs   (Toll-Like Receptors) are just plain interesting, but I don’t think many people are familiar with them.  They’re part of the innate immune system:  they don’t learn from experience, as happens with the adaptive immune system (recombination,  clonal selection and all that): they just know.  Born that way.

They sense pathogens by detecting molecular patterns characteristic of major classes of pathogens that we just don’t have.  These are called PAMPs (pathogen-associated molecular patterns). They can detect  lipopolysaccharide (LPS), characteristic of gram-negative bacteria. and peptidoglycan, characteristic of gram-positive bacteria. Some detect viral-double-stranded RNA.

There are ten TLRs in humans.   Generally, they react with molecular patterns  that we don’t even have. TLR-1 recognizes bacterial lipoprotein and peptidoglycans (strep and staph), TLR-2  recognizes bacterial peptidoglycans( gram-positive bacteria)  and zymosan (fungi), TLR-3 double stranded RNA (viruses) ,  TLR-4 lipopolysaccharides (salmonella) , TLR-5 bacterial flagella (listeria) , TLR-6 bacterial lipoprotein, TLR-7 single-stranded RNA (viruses) , TLR-8 single-stranded RNA(viruses) , TLR-9 CpG DNA (bacteria) .  TLR-10 appears to play an inhibitory role, down-regulating TLR-2 .

Back in the days when vaccine development was cutting-edge, I think that people knew that the body automatically reacted to some pathogens, but it has taken a long time to discover the complex details, not that we’re quite done yet.

P.S. according to some, one factor inducing Pygmyization was the high pathogen load in dense tropical jungles.  I don’t know if that was the case, but if so, considering  that it looks as if African Pygmies (also Bushmen) admixed a bit  with a very divergent hominid population (more divergent than Neanderthals) , it wouldn’t be surprising if they picked up some immune system gene variants that helped deal with that jungle environment.

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