What has never made sense to me is that the IQ effects aren't equally visible across income/class groups, but we know there are millions of wealthy people living in old housing in Boston and NYC and Providence and so on. Lead levels in those houses must be just as high, right? But those kids aren't experiencing the same IQ effects. Surely this suggests that something else is a bigger factor?

It's only 3 IQ points, 1/5 of a standard deviation so not really massive. Of course there are much bigger effects on IQ such as the factors that cause low income children, and people in poor countries to have low IQs which swamp the lead effect.

I imagine frequency and budget of renovations in older housing influences the degree of lead exposure from paint. Poorer neighborhoods may have housing units with largely original (or old enough to contain lead) paint, whereas richer neighborhoods would have a larger proportion of high quality renovations which would eliminate some of the lead paint

If you have money, and it’s your house then you get the old paint stripped when you repaint. If you are buying a home, and there is lead paint, then you negotiate down on the price to compensate for removal.

Landlords of shitty apartments or houses just slap a new coat of the cheapest possible paint over the old.

99.99% of the time there is zero cost reduction due to the presence of lead paint in a normally maintained home. All old homes have it or are assumed to have it.

Stripping is uncommon and can't remove all lead paint from porous surfaces anyway -- like concrete blocks, walls, or ledges.

Landlords use a special lead blocker paint if required to pass inspections. Otherwise -- who knows.

That doesn’t explain it though because lead paint covered by regular paint is quite safe unless your children eat chunks of the wall (quite possible).

Eating chunks of intact wall is unlikely, but surfaces like window sills are very risky because they constantly flake. That’s the nuance of lead mitigation. You can be completely compliant and safe for children with some lead paint on intact walls.

Any tenant can force their landlord to remove lead in those high risk areas (at landlords expense!) if there’s a young child but few renters know about this option.

Not true. Abatement is required. That is not the same as removal. Lead blocker paint or otherwise taking the surface out of contact is usual solution.

I don’t see what was untrue. Abatement still leaves lead paint on the walls. It’s a misconception that lead compliance means “no lead in house”.

Most realtors in Boston don’t bring up lead. There’s a big culture of don’t ask don’t tell.

Wealthy people are more likely to have good childcare (nannies, after school activities) where kids spend less time unsupervised and able to, for example, eat paint chips. For that matter, stuff like chipped paint is less likely to be left in a deteriorating state by more affluent owners.

Just as a matter of common sense and gut-check plausibility, what are we talking about when we talk about "eating paint chips?" Does eating a couple flakes lower your IQ in a measurable way? Seems very unlikely. What are we talking about, then? Do we imagine kids to be shoveling paint chips into their mouth day after day? Surely that's a pretty small number of children (if it's any), nowhere near enough to suggest generational, cohort-level effects. So what is it that we really think is happening here?

My personal experience as a landlord: kids putting their mouths on rails and banisters that are at the level of their mouths. Vivid memories of kids standing around just hanging out on the deck (pre-Internet obviously) with their mouth on the rail. "Does eating a couple flakes lower your IQ in a measurable way? Seems very unlikely." Like asking about the effect of a little second-hand smoke. Probably not a measurable effect, but many people would not be consoled by the inability of the data to register an effect.

It's not just chips, but also dust. Regardless, it has enough effect for the CDC to have a page about it:

https://www.cdc.gov/nceh/lead/prevention/sources/paint.htm

The study in the OP also specifically calls it out:

>Our estimates, based on leaded gasoline consumption, may also have underpredicted high-lead exposures owing to leaded paints and pipes, which tend to aggregate within particular communities (e.g., those with high rates of homes with lead service lines and lead paint in disrepair).

It's from dust on surfaces, toys, and hand to mouth. All toddlers should be tested. There is no surety! Any soils or dust could be contaminated from the heyday of leaded gasoline and paint.

Unemployed people don't need nannies, and they're the poorest. I think you're deliberately avoiding saying that poor people abuse their children, which is true. It's not much about affording anything.

That's because there's this quite "sticky" situation of not every human being being the same. Nobody likes to talk about it and you get shunned or imprisoned for even thinking about it, but the world has actually groups of people with varying levels of intelligence.

a meta study showed the effect to be minimal to zero

https://greyenlightenment.com/2021/08/02/the-effects-of-lead...

That's focused on crime, not IQ/cognition. Crime is not a purely mental phenomenon, so it would likely have a weaker correlation with lead even if the effect is real. The blog post does try to dissemble on the IQ question, but the only evidence presented shows a significant effect of lead (contra the blogger's thesis).

there's this thing about the modern internet era which makes it possible to find a study to debunk (or support) pretty much any idea/theory you want.

specially in the midst of an information/propaganda war

all I'm trying to say is that I have decided not to think in the way you just did e.g. "where's that study which supports what I already believe?". It doesn't seem like a good tactic anymore

This is nothing new, it's a defect of humanity that has existed forever. It's also a problem that has been solved through the scientific method and peer review.

It goes against our nature, so it's a skill that needs to be learned and practiced. This means that the average person isn't going to have those skills, and even people with those skills aren't all going to be experts.

What is new is that the internet is leading every random idiot to believe that they're an expert on everything. So finding a link to a "study" with a title that sounds like it supports your point (without even reading it, and definitely without critically evaluating it) is seen as doing research.

> all I'm trying to say is that I have decided not to think in the way you just did e.g. "where's that study which supports what I already believe?". It doesn't seem like a good tactic anymore

You might be victim to what I described above. Finding a study that already supports what you believe was never a "good tactic". In fact, calling it a tactic makes it seem as if it's an adversarial thing where there's a winner and a loser. It's not. Facts and truths aren't partisan (ignoring them is)

+1 to this response.

To add, playing a paper like a trading card is essentially an appeal to authority[1].

Readers, you have to build mental a model and use causal mechanism and research studies as evidence, not proof. Accept the models which are stronger than the ones you have, even if they make you uncomfortable or conflict with your preconceived notions. Its ok to flip between conclusions as new evidence presents itself.

https://en.m.wikipedia.org/wiki/Argument_from_authority

> all I'm trying to say is that I have decided not to think in the way you just did e.g. "where's that study which supports what I already believe?".

Hmm.

It looks like you're ascribing to the above comment the thought process: "I'm only looking for studies which only tell me that which I believe." However, the above comment doesn't seem to be saying this. They thought there was more to the story and are querying for the rest of the story.

Meanwhile, you seem to ascribe to yourself the quality of not searching for data that supports what you already believe.

However, it seems to me that searching for more studies (even if you're only looking for data that confirms your bias) is a better outcome than assuming (without more proof) that people who aren't you are thinking "the bad way"TM.

I mean, if you had searched for additional proof to discover that what you already thought was true about above commenter (ie they were thinking the bad way) you might have discovered that they in fact were simply looking for additional context due to recalling past events that indicated that there might have been additional context.

It also does not help that many scientific papers suffer from a reproducibility problem.

But I hate to sink into defeatism and assume that there is no such thing as objective fact unless I do the experiments myself (and get them right...).

> I have decided not to think in the way you just did e.g. "where's that study which supports what I already believe?"

I'm not sure you have if you immediately assume what veltas believes because they're asking to be reminded about another study. Seems like projection.

My personal opinion is that it's less noble to close your ears to new information once you've found the information that you prefer than it is to look for more information when you don't like the information you have.

I'm sort of asking if anyone remembers this as well, was posted on HN, I probably could find it myself but since I don't have the time right now I thought I'd make the comment!

Indeed. One issue we have today is a glut of scientific information, some of which is high quality and some isn't. Also, some will later be shown to be false, and some correct, in any given context.

It's not enough to say simply that a study exists (even if it is a large meta-study); it's necessary to actually read it in full and critically appraise it.

But ain't nobody got time for that.... which is a problem!

If they don't have time to read the paper, they aren't investing in the argument enough, and at that point you know the other person is not open to being wrong, which then you respect and end the conversation.

On a one-to-one basis, that might be one approach.

On a system- or industry-wide basis, this approach fails to address the real issue of the significant time taken for evidence to reach patients. Simply walking away leaves the problem unresolved.