This is interesting, I wonder if there's anything to it: International variation in IQ – the role of parasites (paper) by Christopher Hassall of U. Carleton.

It strikes me as the sort of thing that could be as big an issue as lead in the environment. Raise the sanity waterline: improve health!

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This isn't the only evidence which has suggested that parasite load has a substantial impact. Of course, there's the fundamental issue that this provides a very neat explanation for the Flynn effect since not only has IQ gone up across the board, the Flynn effect hit diminishing levels in the most wealthy countries, while still going on in the less well-off ones. In the United States at a state by state level, there's a correlation between parasite load and lower average IQ. That link also discusses how this effect remains even after one controls for wealth and education.

And enough food.

edit: actually, obesity is becoming a worldwide problem, not just in first-world countries, so we may be doing substantially better on this one than in the past.

Yeah, I didn't mean "therefore we should make everyone morbidly obese to raise the general intelligence level", I mean that having obesity indicates you have enough food (since too much food hasn't really been that widespread a problem before this).

Hmm. Whenever someone mentions that undernourishment is bad, people take that to mean that obesity is good, and vice versa. Is the obvious fact that the relationship between body weight and health needn't be monotonic not really that obvious, or is the topic of body weight just another mind-killer?

I think pretty much anything can be turned to stupid purposes if people try hard enough. And they consistently do.


Think it's because people don't separate energy intake and nutrition as two independent considerations. Re: supersize me. He had an oversupply of energy leading to obesity but also was suffering from malnutrition. Assuming in that specific case his energy needs were well met but possibly his mental performance would have suffered due to malnutrition.

Edit - also the outcomes of too much of either are quite different. Excess energy generally produces obesity, excess nutrition can result in poisoning. Symptoms of either represent themselves in completely different ways physically / mentally.

I agree that i believe iodine supp is a good thing, but i am now worried that if used in areas with chlorinated water, it may end up causing problems.

Here is a study that shows cranking up to 130mgs (not mcgs) can cause congenital problems

and here is a new one

"Chlorine or chloramines in your tap water can react with the iodized table salt you add to your food, creating a kind of acid called hypoiodous acid. This in itself isn't cause for concern, but the acid can then react with the food and other organic matter in the tap water to create cooking iodinated disinfection byproducts (I-DBPs) - molecules that are almost completely new to researchers. For the new study, the team identified some molecules and tested their toxicity.

Using cutting-edge chemistry techniques, they identified 14 completely new molecules and determined the structure of nine molecules. They then carried out tests to see how toxic nine of the molecules are and found that some of the molecules are 50-200 times more toxic than others.

The cooking conditions, such as the type of water and salt used, the cooking temperature and time, had an effect on the formation of I-DBPs."

I am reading up on iodine supp, and came across a comment that said Germany is iodizing everything lately, and is seeing an increase in Hashimoto disease. Havn;t seen anything to back that up either, but caught my eye.....

Nothing on it in Wikipedia

and my google-fu mostly brings up wastewater treatments.,

CellBioGuy posted a study of perchloarates in drinking water, in a discussion on thyroid hormones that may also be relevant

"Statistically significant changes in TSH and thyroid hormones were observed at all AP dosage levels tested; however, no thyroid organ weight or histopathological effects were observed at AP dosage levels < or = 1.0 mg/kg/day. In the absence of thyroid organ weight and histopathological effects, the toxicological significance of TSH and thyroid hormone changes at AP dosage levels < or = 1.0 mg/kg/day remains to be determined."

From a response to a different attack on Lynn and Vanhanen:

Right. As I pointed out in my review in 2002, Lynn and Vanhanen's finding of an average IQ of 70 in black Africa is strong evidence in favor of the nurture position that a better environment can raise IQs, because African Americans, who appear to be about 4/5th black, score 15 points higher.

. . .

Moreover, there are still some low-hanging fruits where 3rd World countries would benefit from public health programs that succeeded in the U.S. in the first half of the 20th Century in boosting IQ directly or or in boosting mental energy. Fortifying salt with iodine eliminated the medical syndrome cretinism. while fortifying wheat with iron also eliminated an IQ-sapping medical condition. The Rockefeller Foundation's war on hookwarm greatly benefited the physical and economic energy of Southerners by ridding them of a parasite.

I haven't studied these issues, but I will note that Steve Sailor and are considered by many people to be racist bigots. Here, for example, is a VDARE article defending white supremacy:

White supremacy, in the sense of a society in which key decisions are made by white Europeans, is one of the better arrangements History has come up with.

This doesn't mean that Sailor's claims in the article you quoted are false, but it might mean that Sailor is unusually susceptible to motivated cognition in a particular direction when it comes to racial issues.

Also, as a matter of community strategy, I'll note that citing sources like with apparent approval might make people of color feel unwelcome on LessWrong, even if the specific quoted claims are correct — just like citing Roissy might make women feel unwelcome even if you only quote true claims he has made.

Also, as a matter of community strategy, I'll note that citing sources like with apparent approval might make people of color feel unwelcome on LessWrong, even if the specific quoted claims are correct — just like citing Roissy might make women feel unwelcome even if you only quote true claims he has made.

Thank you for saying this. You may need to (I won't say "like to") read up some of the past race-vs-IQ discussions on LessWrong and work out how to discourage people from saying boneheaded scientific-racist shit in them, c.f. last time I dared note this was actually a serious problem. (The recent downvoting into oblivion of the "race realist" post, and of the author's frothing responses in the comments, was most encouraging IMO.)

I think not mentioning Roissy here when appropriate is a bit silly considering there is such great overlap in the blogosphere. Robin Hanson still directly links to him.


I disagree with this.


Also note that there is at least one plausible candidate for a nurture variable among African Americans in low breast-feeding rates.

IIRC, breast-feeding rates were plummeting in Europe in the late 20th century, but there was no substantial decline in IQ as far as I know.

The Flynn effect has been stopping in Europe in past decades, to name one observation.

This is in line with the article on Toxoplasmosis, a parasite known to make rats fear cats less, and its affects on the human nervous system. It is intriguing to consider at the very least.

Two medical articles: Toxoplasma gondii and Schizophrenia and Effects of Toxoplasma on Human Behavior respectively.

all toxo, all the time

and i still like the trade article, How Your Cat is Making You Crazy


The name of the institution is "Carleton University".

I like these links. Even if it's just the link. They're nowhere near overrunning anything.


It strikes me as the sort of thing that could be as big an issue as lead in the environment.

Lead was fairly easy to remove as a cause of low-IQ individuals. Pathogens, not so much.

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From the voting patterns it appears that this has probably gotten at least three downvotes. Could the people who are downvoting David Gerard's link explain why they are doing so?


I have not voted on it, but if I were downvoting, my reasoning would run that this is a single link which many of us heard about at the time, and Gerard is not providing any context, real commentary, or comprehensiveness, and to some extent, he's focusing on uninteresting things: iodine is way cheaper than parasite prevention, as effective, and comes with nifty bonuses like 'increases the IQ of females more than males'. As well, the appeal to sanity waterline is a little misplaced without any reference to any of the papers I've been collating in

Discussion has low standards, of course, but 1 link and 3 sentences is a bit low.

comes with nifty bonuses like 'increases the IQ of females more than males'.

Why is that a bonus?


Because that makes iodine an intervention easier to market to feminists and anyone with feminist leanings, and increases in female intelligence may have positive effects on particularly benighted and distasteful countries like Afghanistan or Pakistan.

Because in the eyes of the majority of western elites, poor women have higher status than poor men.

Do you have evidence for this claim? Note that this is not the same thing as claiming that in poor countries, women are often worse off than men.

I think it is obvious that helping women is better for signalling than helping men. This is enough to conclude that something which helps women more than men will be easier to promote.

The question is only why helping women is better signalling than helping men. (Even mentioning that poor men are excluded from women-oriented activities is low status.) One explanation is that poor women have it worse than poor men, so it is rational to give more help to poor women. Other explanation is that poor men have lower status than poor women, therefore activities for helping poor men are also lower status than activities helping poor women. These explanations are not contradictory.

I have no hard data; it just seems obvious to me that men are often judged by their ability to "win", while women are often judged by other criteria (such as beauty, etc.). Therefore the fact that a specific man needs help brings him greater status penalty than it would give to a woman. (Also on the opposite end of scale, success brings him greater status bonus; a rich man has higher status than a rich woman.) There is no male equivalent of "damsel in distress"; a helpless man worth rescuing is almost an oxymoron. This all makes sense from evolutionary perspective: in an ancient environment, if a male cannot fight and generally take care about himself, why spend group resources on his survival? In today's society it's not just about fighting, but the attitude translates to other things.

I think there are two pieces-- one is that helpless women are perceived as more worth helping than helpless men, as you say. The other piece is that women are perceived as more likely to help children, and helping people who are likely to be helpful is more efficient.

Quick and dirty assessment: if poor men and poor women had approximately equal status, then we'd expect the following:

  1. People would value nonprofits that primarily help women as equal or lesser in value to equivalent nonprofits that help all (depending on the strength of anti-discrimination sentiment.) So, you wouldn't see many nonprofits expend resources getting the message out there that they primarily help women.
  2. There would be an equal number of nonprofits that primarily help women and those that primarily help men, and they would be about equally loud about it.

This is pretty demonstrably not the case. (Quick google: compare the marketing resources devoted to vs.

That could also be explained by people preferring helping women to helping men because they expect men likely to feel insulted/humiliated when offered charity. Or because they are more likely to perceive distant/foreign/poor men as potential threats.

The argument I've seen is that microlending works better when it's offered to women. Women are claimed (I haven't checked this) to be much more likely to put the money into supporting their families rather than spending it on personal consumption.

I have seen a study that supports this. One of the leading uses men made of money was throwing parties to show how well off they were.....

This seems to run into exactly the problem I brought up. Women in poor countries having higher status than men in the eyes of the West is not the same thing as the eyes of the West seeing women as worse off. If women are worse off then putting more effort into helping them may have higher marginal return than just helping men or helping everyone. What you've pointed to isn't good evidence for your claim.

It does not seem likely to me that this gap is entirely due to poor women being overwhelmingly worse off than poor men. Indeed, given the higher variance of men on a number of traits, it seems very unlikely to me that the worst off of men are better off than the worse off.

Given that "charity is not about helping," this discrepancy is more likely due to the status-induced motivated ignorance of philanthropists, than a rational cost-benefit calculation of where money can do the most good. (As a practical matter, I do think it's plausible that microfinance is more workable among women in the regions that Kiva has decided to target. But I don't think that's the motivation that shines through from the copywriting.)

Indeed, given the higher variance of men on a number of traits, it seems very unlikely to me that the worst off of men are better off than the worse off.

I'm not sure how you would effectively measure the very worst off in any population. But this has other problems as well. First, most of the traits that males have high variance are things like mental illness where there's really not much we can do that is at all efficient even in the developed world, much less in poor countries. Second, what matters is not the absolute worst, but rather what the average level is like. If the average female is worse off than the average male, then it is likely that putting more resources into helping females will have higher pay-off than helping males.

Your analysis also ignores the basic fact that many of these societies are extremely discriminatory in their treatment of women. To use the example that you brought up of Kiva, part of why more microlending has been targeted at women more than at men is because it is often much easier in these societies for men to get loans through pre-existing social chanels.

Given that "charity is not about helping," this discrepancy is more likely due to the status-induced motivated ignorance of philanthropists, than a rational cost-benefit calculation of where money can do the most good.

I think you are engaging in a false dichotomy here. While charity is to some extent about status, it is also about actively helping. Groups like Village Reach wouldn't do very well if that weren't the case. Village Reach has effectively reached near optimal funding rates at this point in time. And other genuinely efficient charity groups are also doing quite well.

Furthermore, even charities like the Make A Wish Foundation get substantial anonymous donations or donations where the donors don't spend that much effort talking about it. This is because there's a third cause for donations- feeling like one is being helpful and good (or as is frequently termed here "warm fuzzies"). Some of this discrepancy also likely due to the fuzziness from helping people who are not only badly off but are actively mistreated in their own countries. The only charities that could possibly produce more warm fuzzies are charities for abused and abandoned puppies and kittens.

I downvoted it because I want to restrict LessWrong to discussions about rationality. This is not such a discussion (even though it mentions IQ).


Is there any sort of FAQ or guideline about which topics "are about rationality" and which "are not about rationality"? I think it's a little disingenuous to downvote because it doesn't satisfy your definition of being "about rationality," as opposed to merely writing a comment that says, "I am not sure that this post is sufficiently on topic."

I am also curious how much of the regular LW reading community feels the same way. I would like to restrict top-level posts to being directly about rationality and the topics discussed in the sequences, but I am also glad there is a sort of "overflow" area where the topics of posts are free to have higher variance. I also conjecture that by opening up the Discussion part of LW to more haphazard posts, readers can get a higher sense of affiliation with other readers and this has a positive effect on the effort expended by the marginal reader (at the expense of lowering the site's overall signal-to-noise ratio). My view is that that trade-off is clearly worth it, but you seem to prefer a different view.

Why is it disingenuous?

Downvoting/upvoting is how the community signals, in a low-bandwidth easily-aggregated distributed fashion, that certain things are desired by its members and other things aren't.

As for how I feel about it personally... hm.

I expect that as the topics discussed on this forum become of more general interest to the Internet community, the forum will attract a membership that more closely resembles the Internet community. Personally, I consider that a net loss, but I don't see a plausible Schelling point on this slippery slope that we're already on anywhere nearby, so I expect the slide along that slope towards maximum accessibility to continue; I try not to argue with the weather.

That is, I consider the likely increased sense of affiliation to be an inadequate tradeoff for the likely increased noise, but I also think that ship sailed a long time ago. (If I had to mark a point, I'd say it was the inclusion of HP:MoR. The fact that without HP:MoR I myself would likely never have found LW is, I admit, ironic, but doesn't change my conclusion... after all, it's not clear to me that I add much of value to the site, even by my own standards.)


Sorry, I should have been clearer; I think it is disingenuous to downvote for that reason if there is no FAQ or guideline expressing the current instantiation of the community's preferences for what is on- or off-topic.

I am all for using a numerical mechanism like voting to aggregate information, but it does come with a reputation cost for people who make the effort to create a post or pass on a link. So it does more than just signal what is liked or disliked; it also has a personal element that may discourage people from trying. If the expectations are clearly spelled out, then voting/downvoting is fine and can be interpreted against that informative backdrop.

Also, this sort of voting allows us to aggregate a coarse "yes" or "no" kind of preference about a post, but I think it would be pretty difficult to impute nuanced preferences, such as classifying topics and sub-topics as on-topic or off-topic, just by aggregating these votes. There's no clear delineation of the "why" behind the vote, and that metadata is more important for understanding the squiggly, discontinuous boundary between "on-topic" and "off-topic". Without the "why" metadata, we're getting a workable, but very coarse, low-resolution, smoothed boundary between the two. I advocate that a FAQ or guidelines for downvoting is a low-cost method to raise the resolution of that boundary.

I agree that the signal being sent is coarse-grained.

I agree that finegraining it is a lovely thing for people to do if they can do it in a way that's low-cost to everyone else.

I disagree with your implicit separation of signalling community (dis)approval on the one hand, and reputation costs on the other. The reputation in this case is precisely a function of community (dis)approval; I don't see how you can sensibly separating them. If I endorse explicitly signalling community (dis)approval at all (which I do), I can't help but endorse explicitly raising/lowering reputation.

My only concern with the FAQ approach is the question of what an individual voter whose reasons for (dis)approval don't align with the FAQ ought to do. If I'm understanding you, your idea is that the FAQ trumps the actual preferences of people in the community -- that is, I'm expected to vote in accordance with the FAQ rather than my own preferences. That makes the existence and contents of the FAQ an implicit power structure, and such things are best approached with caution.

That said, I don't object to it if so approached.


I don't understand the disagreement with splitting the reputation. For example, a really trivially easy way to do it would be like this: On every post, have a thumbs-up/thumbs-down vote button that is specific just to that post, and then have a separate thumbs-up/thumbs-down button that appears next to the name of the user who made the post.

If you just dislike that particular post because it is off-topic, but you think the poster had the intention that it was on-topic (you just dispute that they were correct in their intention), then just downvote the question and not the user. Then the user voting is a signal of an individual's favor in the community and the post voting is a signal of the community's preferences for topical content.

I'm not advocating that we go through the trouble of doing it that way, but it would be an easy way to decouple the second order effect by which a user can feel personally discouraged if a post he or she thought was relevant and interesting is not seen that way by others. Their reputation as a contributing member may remain unchanged; but that particular post is signaled as uninteresting/noisy.

I would like a FAQ that functions much the way the guidelines function at the Stack Exchange websites. Without any guidelines, downvotes are chaotic and lose meaning. If a typical user doesn't like a post, but the reason for dislike is not covered by the FAQ, they can still write a comment, or make a post in one of the Stack Exchange meta sites (to argue constructively for getting their preference category into the FAQ/guidelines). These signal the information and successfully decouple it from what the community says it wants in the FAQ.

Re: separating post-reputation from user-reputation...

You're right; I'm wrong.

Re: FAQ...

Ah, I see... documenting the most-likely-default but not treating it as an expectation.
Yeah, I can see where that could work.

I intended it as actually on-topic, fwiw.