17 ms·

Has the lead-crime hypothesis been debunked?

127 points by monort 5y ago

andi999 5y ago
What is the lead crime hypothesis?
- chrisseaton 5y ago
  The abstract of the paper describes it.
- dcminter 5y ago
  Lead (Pb) the metal. https://en.m.wikipedia.org/wiki/Lead%E2%80%93crime_hypothesis https://en.m.wikipedia.org/wiki/Lead%E2%80%93crime_hypothesi...
- toxik 5y ago
  Lead causes people to behave aggressively and erratically. The idiom “mad as a hatter” comes from the fact that hatters were around lead a lot for some reason I forgot. Edit: Ah, apparently it was mercury, not lead. Cute anecdote anyway.
  - dcminter 5y ago
    I think you're confusing lead with mercury for the hat-making connection.
    - nytgop77 5y ago
      why do you need either of those for making a hat?
      - Spooky23 5y ago
        When felt was made from animal fur, it made it easier and less gross the remove the hair from the hide and soften it. Previously, urine was used.
        lostlogin 5y ago
        Yikes. Knowing what we know now, is mercury the worse option?
        Spooky23 5y ago
        It depends. Urine is not pleasant, but is usually safe to work with. I’d rather smell than suffer brain damage. :)
        redis_mlc 5y ago
        Urine is cleaned by the kidneys. Surgeons drain the urethra directly into the body during kidney surgery because it's antiseptic. So urine is not gross or dirty. (Some idiotic US town a few years ago considered draining their large water reservoir because a teen urinated from the bank. Nevermind that fish and birds do that all day long. But the residents had no common sense.)
      - snowmanbob 5y ago
        shiny when applied to silk.
  - cafard 5y ago
    Hatters used mercury, not lead.
  - Tade0 5y ago
    I knew a person who suffered from lead poisoning (long term occupational exposure). She wasn't aggressive in any way, just not really "here".
    - arbitrage 5y ago
      Did she ever get better?
      - Tade0 5y ago
        Unfortunately not. Or, any chance for that was lost when she had a stroke.
    - Gauge_Irrahphe 5y ago
      Lead is needed for the brain. The person is fully there (in fact more than before) they only stop uncontrollably reacting to everything, and stand straight, instead of being all wobbly.
  - api 5y ago
    Mercury and lead poisoning have similar effects.
- veqz 5y ago
  "The lead–crime hypothesis is the association between elevated blood lead levels in children and increased rates of crime, delinquency, and recidivism later in life."[1] Basically, during the 20th Century, lead were used in a lot of products, including gasoline and paint. To shocking surprise, it turned out that this lead slowly ended up in our environment, and built up in our bodies. The hypothesis is that because virtually the entire population got lead poisoned, we became more affected by "learning disabilities, decreased I.Q., attention deficit hyperactivity disorder, and problems with impulse control", which again leads to more crime. Lead was eventually phased out (no thanks to the companies behind the products), and this correlated with a drop in US crime-rates in the early 1990s. Since then there's been lots of discussion on why the crime rate dropped. The removal of lead from the environment is one (an alternative, but not mutually exclusive, hypothesis is the legalized abortion and crime effect[2]). [Personally, I've been wondering how this also affects other qualities of the people affected... Would people born before the 1970s have been more intelligent than they are currently? Could this have given us better political leadership, and better secondary and tertiary effects?] 1: https://en.wikipedia.org/wiki/Lead–crime_hypothesis https://en.wikipedia.org/wiki/Lead–crime_hypothesis 2: https://en.wikipedia.org/wiki/Legalized_abortion_and_crime_effect https://en.wikipedia.org/wiki/Legalized_abortion_and_crime_e...
  - cptnapalm 5y ago
    I wonder when someone will see if the rise of home gaming consoles had an effect. A Nintendo effect, if you will.
  - Gauge_Irrahphe 5y ago
    Why did the most enormous progress happen when this poisoning was widespread? And it wasn't only once but at least twice: In Ancient Rome lead was also widely used. The whole idea of "chronic toxicity" is bunk. It will eventually turn out that lead is essential.
- lostlogin 5y ago
  Some good article here - but this is my favourite. https://www.motherjones.com/environment/2016/02/lead-exposure-gasoline-crime-increase-children-health/ https://www.motherjones.com/environment/2016/02/lead-exposur...
  - SeanLuke 5y ago
    By the same author.
- pvaldes 5y ago
  Poisoning with lead has been linked with sudden rage attacks and homicides. Lead affects the nervous system.
Retric 5y ago
Hypothesis before reading: Question in the headline, answer is no. Confirmed, sigh.
- philjohn 5y ago
  Betteridge's Law of Headlines - https://en.wikipedia.org/wiki/Betteridge%27s_law_of_headlines https://en.wikipedia.org/wiki/Betteridge%27s_law_of_headline...
- deleted 5y ago
  [deleted]
gttalbot 5y ago
Well, we're not "post-lead" anyway. Particularly in larger, older cities there is a lot of lead paint around, and this tends to be clustered in older, poorer neighborhoods with unrenovated and more poorly maintained dwellings. I'm not sure this is a good meta analysis.
- corty 5y ago
  And there are other neurotoxic compounds still in common use, such as mercury-aluminium-amalgam for cheap dental work. That would also confound all the simple studies. I'm afraid there can't be a firm conclusion without an in-depth study of heavy metal prevalence in bloodstream and bones vs. criminal behavior. Just plotting sales figures of leaded gas vs. murder rates doesn't say anything. Any more elaborate study is of course smaller and more expensive, so won't be done as easily.
  - shreyshnaccount 5y ago
    they still use that? even when it's a known neurotoxin?
    - NickNameNick 5y ago
      I had the impression (although I can't remember where from) that amalgam fillings were surprisingly benign. They're small, leach surprisingly little, and what they do leach is in a form that isn't readily bio-available. Which isn't to say they're completely harmless, just not so bad as you might expect.
      - shreyshnaccount 5y ago
        makes sense thanks for sharing
      - deleted 5y ago
        [deleted]
      - anonuser123456 5y ago
fouc 5y ago
> This means that 22 out of 24 studies found positive associations. > The authors present a model that says there should be more papers showing negative effects just by chance. To the layperson it sure looks like the lead-crime hypothesis is confirmed. Really curious to see a more in-depth follow-up on this meta-analysis.
- HWR_14 5y ago
  It's interesting because, as I understand it (based solely on the article's summary), the meta-analysis asserts that the current lead-crime value is wrong. Either it is much lower than expected because we should see more ambiguous papers and the lack of them points to bias in the study/publish methodology -or- its much stronger than expected because we cannot find many counterexamples. The original publishers just went with the first, the article asserts the second.
  - corty 5y ago
    I think both conclusions are wrong. Since this is a meta-study, drawing conclusions from the absence of null-results and the absence of clustering is prone to a lot of confounders. The article mentions publication-bias, where non-null-results are published with a higher probability. Other such confounders will exist, e.g. data-availability-bias in certain places and populations, location-bias because researchers study their usually first-world, urban, university-town surroundings more often. Community-bias, because researchers tend to cluster and get inspiration for new studies from their community and peer group on the conferences they visit. Data-similarity-bias, because they can only compare studies where data can be normalized to a common base. Quality-bias, because they necessarily include well-done and badly-done studies, in different amounts, usually without weighing them properly, because that is very hard to do. Most of those confounders cannot be corrected for. So one could draw a conclusion like "we do see null-results in the expected amount and clustering in the expected amount, therefore the result of this meta-study is a confirmation of the lead-crime-hypothesis". But the only correct opposite conclusion is "we do not see null-results and clustering in the expected amount, so our result is 'we do not know'". So the imho correct interpretation of the meta-study is "don't know, further research or better meta-analysis needed".
jsnell 5y ago
> I don't get this. If, say, the actual effect of lead on crime is 0.33 on their scale (a "large" effect size) then you'd expect to find papers clustered around that value You'd expect them to be clustered around that value symmetrically, right? That's clearly not the case in the diagram that the blog post author quoted. There's a cluster around very weak positive effects, and then a long tail of strong positive effects but no matching long tail of weak negative ones. This suggests either that the negative results were truncated out, negative results have been hacked to positive ones, or there is some confounding factor at play. And I think the modeling in the paper is just an attempt at finding the confounding factor, and not finding one. That said, the author's arguments around negative results being publishable in this field + studies not disappearing seem pretty strong. (Or, at least this is my reading of the situation as a total amateur.)
- codesections 5y ago
  > This suggests either that the negative results were truncated out, negative results have been hacked to positive ones, or there is some confounding factor at play. Here's a potential confounding factor: maybe the cluster of very weak positive effects includes some studies that initially showed very weak negative effects but that had their methodology tweaked to avoid showing an "impossible" result. (I don't think anyone argues that atmospheric lead _decreases_ crime rates.) If so, that would mean that there are some "missing" negative studies, but that there are also "too many" zero/very low result studies. If corrected for that, I suspect that the meta-analysis would show a positive effect size, though lower than 0.33.
  - jsnell 5y ago
    That's the "negative effects hacked to positive ones" explanation.
  - geeB 5y ago
    > I don't think anyone argues that atmospheric lead _decreases_ crime rates. Although in principle I don't see why it couldn't be the case, as leas poisoning also has symptoms such as depression and fatigue, which could marginally sway people towards inaction.
_0ffh 5y ago
Though I think I get the argument, it seems quite absurd that we now have arrived at "The absence of evidence of absence is evidence of absence."
lucb1e 5y ago
Since it's never explained what this is about, before you read the article you might want to know: > The lead–crime hypothesis is the association between elevated blood lead levels in children and increased rates of crime, delinquency, and recidivism later in life. (Wikipedia) (I was interpreting "lead" as related to leadership or being (mis)lead, and was thoroughly confused for the first few paragraphs until I decided to just look it up myself.)
- jeffbee 5y ago
  So, the evidence for this hypothesis is extremely strong. There have been studies of children who did or did not get treated for high blood lead levels, and those who did not had much higher rates of criminal behavior. These were children from the same schools, same neighborhoods, same time. All the confounding circumstances are controlled. The Lead-Crime Hypothesis may also refer to the idea that lead is the main reason for the global crime wave that peaked in 1990. The evidence for this is less convincing.
  - monort 5y ago
    The strong evidences you are talking about are usually confounded by socioeconomic status. One recent longitudinal study in New Zealand have found only a very weak correlation: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5801257/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5801257/
    - jeffbee 5y ago
      That study isn't as powerful as what I mentioned. That is a longitudinal study of children who were exposed to lead, and their life outcomes. The study I want to mention was of children, all of whom were exposed to lead, but only some of whom were treated for it, based on a threshold of blood lead concentration. Figure 4 in this paper is particularly compelling. They show a strong correlation between blood lead levels and violent criminal behavior in later life, but the intervention group, who were exposed to lead but received treatments for it, had much lower rates of crime. You should read it to see if you think they didn't control for socioeconomic factors well enough. Section II and Table 1 in particular. https://pubs.aeaweb.org/doi/pdfplus/10.1257/app.20160056 https://pubs.aeaweb.org/doi/pdfplus/10.1257/app.20160056
amadeuspagel 5y ago
It's insane that publication bias is still a thing that has to be considered in a meta-analysis, that you can't just find any study on a topic ever made.
100011 5y ago
In US, roughly 13% of the population (blacks) commit roughly 56% of homicides. That is a per capita murder rate 8.2 times higher than the non-black murder rate (2019 FBI statistics). The murder rate among the Hispanics, who are almost as poor as blacks, is less than half that among blacks. But it's the lead I'm sure, lol.
in3d 5y ago
> In fact, because the sample size for homicides is so small, exactly the opposite is true. In general, studies that look at homicide rates in the '80s and '90s simply don't have the power to be meaningful. The unit of study should always be an index value for violent crime and it should always be over a significant period of time. Homicide rates are used for good reasons: they are least subject to reporting variations, they are hardest to fudge, and it’s the most serious crime. Some evidence against the lead-crime hypothesis is the recent (2020-2021) jump in homicides in the U.S.
- ceejayoz 5y ago
  > Some evidence against the lead-crime hypothesis is the recent (2020-2021) jump in homicides in the U.S. With a fairly major confounding factor. The hypothesis was never "lead is the only reason there can ever be a homicide". The loss of 20 million jobs in a blink of an eye might well cause a spike. NYC, for example, is dropping back down. https://www.newsweek.com/shootings-down-june-new-york-police-report-almost-100-percent-more-gun-arrests-1607277 https://www.newsweek.com/shootings-down-june-new-york-police...
  - in3d 5y ago
    Not a strong evidence for sure but the loss of jobs is not a good explanation either since there hasn’t been a similar jump in homicides in other countries.
    - ceejayoz 5y ago
      That may point to a difference in lockdown policies, safety nets (for example: https://www.nytimes.com/2020/07/03/business/economy/europe-us-jobless-coronavirus.html https://www.nytimes.com/2020/07/03/business/economy/europe-u...), etc. though.
      - angry_octet 5y ago
        And, you know, gun culture. And a laissez-faire attitude towards other people death in general. I would expect someone to say that people have to take responsibility for their own lead intake, and "people make choices".
dang 5y ago
Some previous lead-crime threads: An Updated Lead-Crime Roundup (2018) - https://news.ycombinator.com/item?id=20101446 https://news.ycombinator.com/item?id=20101446 - June 2019 (11 comments) New Evidence That Lead Exposure Increases Crime (2017) - https://news.ycombinator.com/item?id=17888291 https://news.ycombinator.com/item?id=17888291 - Aug 2018 (147 comments) Lead: America's Real Criminal Element (2013) - https://news.ycombinator.com/item?id=17350912 https://news.ycombinator.com/item?id=17350912 - June 2018 (141 comments) A Basic Cohort Test of the Lead-Crime Hypothesis - https://news.ycombinator.com/item?id=16349365 https://news.ycombinator.com/item?id=16349365 - Feb 2018 (45 comments) New Zealand Study Provides More Support for Lead-Crime Hypothesis - https://news.ycombinator.com/item?id=16023218 https://news.ycombinator.com/item?id=16023218 - Dec 2017 (36 comments) A Study That Bolsters the Lead-Crime Hypothesis - https://news.ycombinator.com/item?id=14488520 https://news.ycombinator.com/item?id=14488520 - June 2017 (121 comments) Lead Water Pipes in 1900 Caused Higher Crime Rates in 1920? - https://news.ycombinator.com/item?id=11625158 https://news.ycombinator.com/item?id=11625158 - May 2016 (67 comments) Lead and Crime: Another Look - https://news.ycombinator.com/item?id=10868980 https://news.ycombinator.com/item?id=10868980 - Jan 2016 (11 comments) Did removing lead from petrol spark a decline in crime? - https://news.ycombinator.com/item?id=7618871 https://news.ycombinator.com/item?id=7618871 - April 2014 (270 comments) Leaded gasoline caused violent crime? Critiques wanted. - https://news.ycombinator.com/item?id=5017804 https://news.ycombinator.com/item?id=5017804 - Jan 2013 (1 comment) America's Real Criminal Element: Lead - https://news.ycombinator.com/item?id=5002806 https://news.ycombinator.com/item?id=5002806 - Jan 2013 (4 comments) The Crime of Lead Exposure - https://news.ycombinator.com/item?id=2609158 https://news.ycombinator.com/item?id=2609158 - June 2011 (3 comments) Has use of lead-free gas decreased the crime rate? - https://news.ycombinator.com/item?id=71878 https://news.ycombinator.com/item?id=71878 - Oct 2007 (4 comments)
aaron695 5y ago
Freakonomics re-visit the abortion crime link and also talk about lead in 2019 - https://freakonomics.com/podcast/abortion/ https://freakonomics.com/podcast/abortion/ The abortion model is simple. Unwanted babies to mothers who don't want them will not grow up well. We know lots of things target IQ, but the lead model is really complex, it hypothetically reduces impulse control across the entire population and with really tiny amounts in the environment. When I see it proven in mice not humans I'll be more convinced. (And not large amount of lead in their water bowl)
tacotacotacos 5y ago
I don’t know much about stats, but the idea that a theory is bunk because no studies have shown it’s bunk is pretty absurd. How many studies fail to show an association between narcotics abuse and crime? Zero? Then it must be fake?
- MontyCarloHall 5y ago
  Let’s say there’s a test that, by pure chance, has a probability of p=1/N of returning an unexpected outcome. If we run that test N times, we expect on average one unexpected outcome, solely due to random chance. I haven’t read the linked paper yet, but its authors’ argument is that they have orthogonal evidence that p in this case should be considerably larger than 1/24, so given 24 total studies on the lead crime hypothesis, at least one should have returned a negative result purely by chance. The validity of this claim depends entirely on whether their argument that p>>1/24 is sound.
  - dllthomas 5y ago
    Though even if it's 1/12, the chance of no negative results by chance is still >10%, right?
- jonas21 5y ago
  I think their argument is a little more subtle than that -- the issue isn't really that there are no negative results, but rather that the shape of the distribution of results is funny. They're saying you'd expect the results to follow a normal distribution centered at some value. Instead, we see a large number of studies clustered just above zero and a right tail, but no left tail. I think they're arguing that this is because the left side of the distribution is unpublished, and without knowing what it looks like, you can't come to a conclusion.
- 6gvONxR4sf7o 5y ago
  Picture a perfect bell curve where the whole left half has been chopped off. If you had an a priori reason to believe it’s a bell curve, then it’s easy to spot the fact that the left half has been chopped off, and easy to spot where the mean would have been.
paulpauper 5y ago
I think it's understandable why the lead-crime hypothesis was/is so popular, because it it's an alternative to the hypothesis that increased incarceration and abortion reduced crime, which, politically, are less popular. It's more politically correct to blame lead poisoning than insufficient policing.
- pasabagi 5y ago
  Well, crime went down worldwide, whereas abortion and incarceration only went up in the US.
  - kube-system 5y ago
    This is exactly why I think environmental, economic, and entertainment factors are the most likely, as they cross political borders. Everyone is always looking for a political angle, but while everyone is arguing over the efficacy of their team’s favorite crime policies, the answer is probably: give every restless teenager an Xbox and some macaroni and cheese.
    - jopsen 5y ago
      Yeah, cultural changes and access to entertainment might be the simplest answer :)
- nwah1 5y ago
  There's at least 16 hypotheses and none of them are that popular. In fact, most people are unlikely to even know that crime has been on a downward trend at all. The lead hypothesis has not been debunked, and if you read the article in the OP you'll find a number of unanswered questions. https://www.vox.com/2015/2/13/8032231/crime-drop https://www.vox.com/2015/2/13/8032231/crime-drop
deleted 5y ago
[deleted]
tootahe45 5y ago
Lead poisoning = lower IQ & educational attainment poor education & lower IQ = locked out of the labor force and more likely to make bad decisions in life not rocket science.
- jopsen 5y ago
  Yeah, maybe.. but like the blog post says: > Nor are they the kind of study where you round up a hundred undergraduates and perform an experiment on them. Do we have good clinical evidence showing: lead = lower IQ? (I'm guessing nobody volunteered for lead poisoning). Thing is that crime reduction could be cultural, or simple widespread video games :) (Maybe it's a bit everything, and lead probably isn't the only environmental improvement we've made)
adenozine 5y ago
Would this not just be correlated with areas of poverty? Typically those areas haven't afforded new plumbing in the post-lead world thus far...
- paleotrope 5y ago
  The lead here was the lead used in leaded gasoline. It was lead in the air.
lamebitches 5y ago
Covid is a bio-weapon. Fauci is the dealer.
jl6 5y ago
It's astonishing to me that any large scale population study can ever prove anything, given how incredibly complex and unique peoples' lives are, and how many confounding factors may play a part at some point in those lives over many years.
- unparagoned 5y ago
  Well scientists don’t just rely on them. They would use them as just part of the puzzle. Do we known the mechanism, can we do causal animal experiments and then is there a correlation in humans.
hristov 5y ago
The lead-crime hypothesis is almost certainly true but the mass media reaction to it just shows how much is wrong with our society. First of all, the lead-crime hypothesis is good news. It is great to realize that small entirely achievable environmental changes can cause such marked improvement in wellbeing in people's lives. But for some reason it has not been accepted as good news by the mass media. And then you have papers like the one discussed by the article that try to debunk the theory on absolutely ridiculous grounds. (You see there are no studies disproving this theory therefore there must be studies disproving this theory, therefore this theory is wrong. What a bunch of BS!) So why is the lead crime hypothesis treated so negatively by our elites? Perhaps to avoid another round of massive litigation. Perhaps to prevent people from finding other ways other pollution can affect people's behavior and thus prevent the banning of other substances and other rounds of massive litigation. Or perhaps to preserve an image key in international culture -- the violent city youth.
- Gauge_Irrahphe 5y ago
  That's just wishful thinking. The costs on health could be massive if lead is essential. (and it very likely is)
- jhbadger 5y ago
  Another possibility is that people just don't like such reductive explanations of human behavior. It's easier to say, well, violent youth is a product of society somehow and it's too hard to come up with a concrete explanation.
  - Hammershaft 5y ago
    I think many people are uncomfortable with the idea that a chemical or unknown environmental change can cause such marked changes in human behavior.
    - michaelmrose 5y ago
      To be even more accurate the older folks are uncomfortable with provable allegations that they are brain damaged.
coding123 5y ago
Its the cameras.
alex_young 5y ago
Isn't this more of a critique of meta-analysis itself? It seems pretty suspect to take a collection of published studies with different populations and different criteria and derive any meaningful meta product from them, especially since we know most research is never actually published.

127 points by monort 5y ago

andi999 5y ago

What is the lead crime hypothesis?

chrisseaton 5y ago
The abstract of the paper describes it.
dcminter 5y ago
Lead (Pb) the metal. https://en.m.wikipedia.org/wiki/Lead%E2%80%93crime_hypothesis https://en.m.wikipedia.org/wiki/Lead%E2%80%93crime_hypothesi...
toxik 5y ago
Lead causes people to behave aggressively and erratically. The idiom “mad as a hatter” comes from the fact that hatters were around lead a lot for some reason I forgot. Edit: Ah, apparently it was mercury, not lead. Cute anecdote anyway.
- dcminter 5y ago
  I think you're confusing lead with mercury for the hat-making connection.
  - nytgop77 5y ago
    why do you need either of those for making a hat?
    - Spooky23 5y ago
      When felt was made from animal fur, it made it easier and less gross the remove the hair from the hide and soften it. Previously, urine was used.
      - lostlogin 5y ago
        Yikes. Knowing what we know now, is mercury the worse option?
        Spooky23 5y ago
        It depends. Urine is not pleasant, but is usually safe to work with. I’d rather smell than suffer brain damage. :)
        redis_mlc 5y ago
        Urine is cleaned by the kidneys. Surgeons drain the urethra directly into the body during kidney surgery because it's antiseptic. So urine is not gross or dirty. (Some idiotic US town a few years ago considered draining their large water reservoir because a teen urinated from the bank. Nevermind that fish and birds do that all day long. But the residents had no common sense.)
    - snowmanbob 5y ago
      shiny when applied to silk.
- cafard 5y ago
  Hatters used mercury, not lead.
- Tade0 5y ago
  I knew a person who suffered from lead poisoning (long term occupational exposure). She wasn't aggressive in any way, just not really "here".
  - arbitrage 5y ago
    Did she ever get better?
    - Tade0 5y ago
      Unfortunately not. Or, any chance for that was lost when she had a stroke.
  - Gauge_Irrahphe 5y ago
    Lead is needed for the brain. The person is fully there (in fact more than before) they only stop uncontrollably reacting to everything, and stand straight, instead of being all wobbly.
- api 5y ago
  Mercury and lead poisoning have similar effects.
veqz 5y ago
"The lead–crime hypothesis is the association between elevated blood lead levels in children and increased rates of crime, delinquency, and recidivism later in life."[1] Basically, during the 20th Century, lead were used in a lot of products, including gasoline and paint. To shocking surprise, it turned out that this lead slowly ended up in our environment, and built up in our bodies. The hypothesis is that because virtually the entire population got lead poisoned, we became more affected by "learning disabilities, decreased I.Q., attention deficit hyperactivity disorder, and problems with impulse control", which again leads to more crime. Lead was eventually phased out (no thanks to the companies behind the products), and this correlated with a drop in US crime-rates in the early 1990s. Since then there's been lots of discussion on why the crime rate dropped. The removal of lead from the environment is one (an alternative, but not mutually exclusive, hypothesis is the legalized abortion and crime effect[2]). [Personally, I've been wondering how this also affects other qualities of the people affected... Would people born before the 1970s have been more intelligent than they are currently? Could this have given us better political leadership, and better secondary and tertiary effects?] 1: https://en.wikipedia.org/wiki/Lead–crime_hypothesis https://en.wikipedia.org/wiki/Lead–crime_hypothesis 2: https://en.wikipedia.org/wiki/Legalized_abortion_and_crime_effect https://en.wikipedia.org/wiki/Legalized_abortion_and_crime_e...
- cptnapalm 5y ago
  I wonder when someone will see if the rise of home gaming consoles had an effect. A Nintendo effect, if you will.
- Gauge_Irrahphe 5y ago
  Why did the most enormous progress happen when this poisoning was widespread? And it wasn't only once but at least twice: In Ancient Rome lead was also widely used. The whole idea of "chronic toxicity" is bunk. It will eventually turn out that lead is essential.
lostlogin 5y ago
Some good article here - but this is my favourite. https://www.motherjones.com/environment/2016/02/lead-exposure-gasoline-crime-increase-children-health/ https://www.motherjones.com/environment/2016/02/lead-exposur...
- SeanLuke 5y ago
  By the same author.
pvaldes 5y ago
Poisoning with lead has been linked with sudden rage attacks and homicides. Lead affects the nervous system.

Retric 5y ago

Hypothesis before reading: Question in the headline, answer is no. Confirmed, sigh.

philjohn 5y ago
Betteridge's Law of Headlines - https://en.wikipedia.org/wiki/Betteridge%27s_law_of_headlines https://en.wikipedia.org/wiki/Betteridge%27s_law_of_headline...
deleted 5y ago
[deleted]

gttalbot 5y ago

Well, we're not "post-lead" anyway. Particularly in larger, older cities there is a lot of lead paint around, and this tends to be clustered in older, poorer neighborhoods with unrenovated and more poorly maintained dwellings. I'm not sure this is a good meta analysis.

corty 5y ago
And there are other neurotoxic compounds still in common use, such as mercury-aluminium-amalgam for cheap dental work. That would also confound all the simple studies. I'm afraid there can't be a firm conclusion without an in-depth study of heavy metal prevalence in bloodstream and bones vs. criminal behavior. Just plotting sales figures of leaded gas vs. murder rates doesn't say anything. Any more elaborate study is of course smaller and more expensive, so won't be done as easily.
- shreyshnaccount 5y ago
  they still use that? even when it's a known neurotoxin?
  - NickNameNick 5y ago
    I had the impression (although I can't remember where from) that amalgam fillings were surprisingly benign. They're small, leach surprisingly little, and what they do leach is in a form that isn't readily bio-available. Which isn't to say they're completely harmless, just not so bad as you might expect.
    - shreyshnaccount 5y ago
      makes sense thanks for sharing
    - deleted 5y ago
      [deleted]
    - anonuser123456 5y ago

fouc 5y ago

> This means that 22 out of 24 studies found positive associations. > The authors present a model that says there should be more papers showing negative effects just by chance. To the layperson it sure looks like the lead-crime hypothesis is confirmed. Really curious to see a more in-depth follow-up on this meta-analysis.

HWR_14 5y ago
It's interesting because, as I understand it (based solely on the article's summary), the meta-analysis asserts that the current lead-crime value is wrong. Either it is much lower than expected because we should see more ambiguous papers and the lack of them points to bias in the study/publish methodology -or- its much stronger than expected because we cannot find many counterexamples. The original publishers just went with the first, the article asserts the second.
- corty 5y ago
  I think both conclusions are wrong. Since this is a meta-study, drawing conclusions from the absence of null-results and the absence of clustering is prone to a lot of confounders. The article mentions publication-bias, where non-null-results are published with a higher probability. Other such confounders will exist, e.g. data-availability-bias in certain places and populations, location-bias because researchers study their usually first-world, urban, university-town surroundings more often. Community-bias, because researchers tend to cluster and get inspiration for new studies from their community and peer group on the conferences they visit. Data-similarity-bias, because they can only compare studies where data can be normalized to a common base. Quality-bias, because they necessarily include well-done and badly-done studies, in different amounts, usually without weighing them properly, because that is very hard to do. Most of those confounders cannot be corrected for. So one could draw a conclusion like "we do see null-results in the expected amount and clustering in the expected amount, therefore the result of this meta-study is a confirmation of the lead-crime-hypothesis". But the only correct opposite conclusion is "we do not see null-results and clustering in the expected amount, so our result is 'we do not know'". So the imho correct interpretation of the meta-study is "don't know, further research or better meta-analysis needed".

jsnell 5y ago

> I don't get this. If, say, the actual effect of lead on crime is 0.33 on their scale (a "large" effect size) then you'd expect to find papers clustered around that value You'd expect them to be clustered around that value symmetrically, right? That's clearly not the case in the diagram that the blog post author quoted. There's a cluster around very weak positive effects, and then a long tail of strong positive effects but no matching long tail of weak negative ones. This suggests either that the negative results were truncated out, negative results have been hacked to positive ones, or there is some confounding factor at play. And I think the modeling in the paper is just an attempt at finding the confounding factor, and not finding one. That said, the author's arguments around negative results being publishable in this field + studies not disappearing seem pretty strong. (Or, at least this is my reading of the situation as a total amateur.)

codesections 5y ago
> This suggests either that the negative results were truncated out, negative results have been hacked to positive ones, or there is some confounding factor at play. Here's a potential confounding factor: maybe the cluster of very weak positive effects includes some studies that initially showed very weak negative effects but that had their methodology tweaked to avoid showing an "impossible" result. (I don't think anyone argues that atmospheric lead _decreases_ crime rates.) If so, that would mean that there are some "missing" negative studies, but that there are also "too many" zero/very low result studies. If corrected for that, I suspect that the meta-analysis would show a positive effect size, though lower than 0.33.
- jsnell 5y ago
  That's the "negative effects hacked to positive ones" explanation.
- geeB 5y ago
  > I don't think anyone argues that atmospheric lead _decreases_ crime rates. Although in principle I don't see why it couldn't be the case, as leas poisoning also has symptoms such as depression and fatigue, which could marginally sway people towards inaction.

_0ffh 5y ago

Though I think I get the argument, it seems quite absurd that we now have arrived at "The absence of evidence of absence is evidence of absence."

lucb1e 5y ago

Since it's never explained what this is about, before you read the article you might want to know: > The lead–crime hypothesis is the association between elevated blood lead levels in children and increased rates of crime, delinquency, and recidivism later in life. (Wikipedia) (I was interpreting "lead" as related to leadership or being (mis)lead, and was thoroughly confused for the first few paragraphs until I decided to just look it up myself.)

jeffbee 5y ago
So, the evidence for this hypothesis is extremely strong. There have been studies of children who did or did not get treated for high blood lead levels, and those who did not had much higher rates of criminal behavior. These were children from the same schools, same neighborhoods, same time. All the confounding circumstances are controlled. The Lead-Crime Hypothesis may also refer to the idea that lead is the main reason for the global crime wave that peaked in 1990. The evidence for this is less convincing.
- monort 5y ago
  The strong evidences you are talking about are usually confounded by socioeconomic status. One recent longitudinal study in New Zealand have found only a very weak correlation: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5801257/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5801257/
  - jeffbee 5y ago
    That study isn't as powerful as what I mentioned. That is a longitudinal study of children who were exposed to lead, and their life outcomes. The study I want to mention was of children, all of whom were exposed to lead, but only some of whom were treated for it, based on a threshold of blood lead concentration. Figure 4 in this paper is particularly compelling. They show a strong correlation between blood lead levels and violent criminal behavior in later life, but the intervention group, who were exposed to lead but received treatments for it, had much lower rates of crime. You should read it to see if you think they didn't control for socioeconomic factors well enough. Section II and Table 1 in particular. https://pubs.aeaweb.org/doi/pdfplus/10.1257/app.20160056 https://pubs.aeaweb.org/doi/pdfplus/10.1257/app.20160056

amadeuspagel 5y ago

It's insane that publication bias is still a thing that has to be considered in a meta-analysis, that you can't just find any study on a topic ever made.

100011 5y ago

In US, roughly 13% of the population (blacks) commit roughly 56% of homicides. That is a per capita murder rate 8.2 times higher than the non-black murder rate (2019 FBI statistics). The murder rate among the Hispanics, who are almost as poor as blacks, is less than half that among blacks. But it's the lead I'm sure, lol.

in3d 5y ago

> In fact, because the sample size for homicides is so small, exactly the opposite is true. In general, studies that look at homicide rates in the '80s and '90s simply don't have the power to be meaningful. The unit of study should always be an index value for violent crime and it should always be over a significant period of time. Homicide rates are used for good reasons: they are least subject to reporting variations, they are hardest to fudge, and it’s the most serious crime. Some evidence against the lead-crime hypothesis is the recent (2020-2021) jump in homicides in the U.S.

ceejayoz 5y ago
> Some evidence against the lead-crime hypothesis is the recent (2020-2021) jump in homicides in the U.S. With a fairly major confounding factor. The hypothesis was never "lead is the only reason there can ever be a homicide". The loss of 20 million jobs in a blink of an eye might well cause a spike. NYC, for example, is dropping back down. https://www.newsweek.com/shootings-down-june-new-york-police-report-almost-100-percent-more-gun-arrests-1607277 https://www.newsweek.com/shootings-down-june-new-york-police...
- in3d 5y ago
  Not a strong evidence for sure but the loss of jobs is not a good explanation either since there hasn’t been a similar jump in homicides in other countries.
  - ceejayoz 5y ago
    That may point to a difference in lockdown policies, safety nets (for example: https://www.nytimes.com/2020/07/03/business/economy/europe-us-jobless-coronavirus.html https://www.nytimes.com/2020/07/03/business/economy/europe-u...), etc. though.
    - angry_octet 5y ago
      And, you know, gun culture. And a laissez-faire attitude towards other people death in general. I would expect someone to say that people have to take responsibility for their own lead intake, and "people make choices".

dang 5y ago

Some previous lead-crime threads: An Updated Lead-Crime Roundup (2018) - https://news.ycombinator.com/item?id=20101446 https://news.ycombinator.com/item?id=20101446 - June 2019 (11 comments) New Evidence That Lead Exposure Increases Crime (2017) - https://news.ycombinator.com/item?id=17888291 https://news.ycombinator.com/item?id=17888291 - Aug 2018 (147 comments) Lead: America's Real Criminal Element (2013) - https://news.ycombinator.com/item?id=17350912 https://news.ycombinator.com/item?id=17350912 - June 2018 (141 comments) A Basic Cohort Test of the Lead-Crime Hypothesis - https://news.ycombinator.com/item?id=16349365 https://news.ycombinator.com/item?id=16349365 - Feb 2018 (45 comments) New Zealand Study Provides More Support for Lead-Crime Hypothesis - https://news.ycombinator.com/item?id=16023218 https://news.ycombinator.com/item?id=16023218 - Dec 2017 (36 comments) A Study That Bolsters the Lead-Crime Hypothesis - https://news.ycombinator.com/item?id=14488520 https://news.ycombinator.com/item?id=14488520 - June 2017 (121 comments) Lead Water Pipes in 1900 Caused Higher Crime Rates in 1920? - https://news.ycombinator.com/item?id=11625158 https://news.ycombinator.com/item?id=11625158 - May 2016 (67 comments) Lead and Crime: Another Look - https://news.ycombinator.com/item?id=10868980 https://news.ycombinator.com/item?id=10868980 - Jan 2016 (11 comments) Did removing lead from petrol spark a decline in crime? - https://news.ycombinator.com/item?id=7618871 https://news.ycombinator.com/item?id=7618871 - April 2014 (270 comments) Leaded gasoline caused violent crime? Critiques wanted. - https://news.ycombinator.com/item?id=5017804 https://news.ycombinator.com/item?id=5017804 - Jan 2013 (1 comment) America's Real Criminal Element: Lead - https://news.ycombinator.com/item?id=5002806 https://news.ycombinator.com/item?id=5002806 - Jan 2013 (4 comments) The Crime of Lead Exposure - https://news.ycombinator.com/item?id=2609158 https://news.ycombinator.com/item?id=2609158 - June 2011 (3 comments) Has use of lead-free gas decreased the crime rate? - https://news.ycombinator.com/item?id=71878 https://news.ycombinator.com/item?id=71878 - Oct 2007 (4 comments)

aaron695 5y ago

Freakonomics re-visit the abortion crime link and also talk about lead in 2019 - https://freakonomics.com/podcast/abortion/ https://freakonomics.com/podcast/abortion/ The abortion model is simple. Unwanted babies to mothers who don't want them will not grow up well. We know lots of things target IQ, but the lead model is really complex, it hypothetically reduces impulse control across the entire population and with really tiny amounts in the environment. When I see it proven in mice not humans I'll be more convinced. (And not large amount of lead in their water bowl)

tacotacotacos 5y ago

I don’t know much about stats, but the idea that a theory is bunk because no studies have shown it’s bunk is pretty absurd. How many studies fail to show an association between narcotics abuse and crime? Zero? Then it must be fake?

MontyCarloHall 5y ago
Let’s say there’s a test that, by pure chance, has a probability of p=1/N of returning an unexpected outcome. If we run that test N times, we expect on average one unexpected outcome, solely due to random chance. I haven’t read the linked paper yet, but its authors’ argument is that they have orthogonal evidence that p in this case should be considerably larger than 1/24, so given 24 total studies on the lead crime hypothesis, at least one should have returned a negative result purely by chance. The validity of this claim depends entirely on whether their argument that p>>1/24 is sound.
- dllthomas 5y ago
  Though even if it's 1/12, the chance of no negative results by chance is still >10%, right?
jonas21 5y ago
I think their argument is a little more subtle than that -- the issue isn't really that there are no negative results, but rather that the shape of the distribution of results is funny. They're saying you'd expect the results to follow a normal distribution centered at some value. Instead, we see a large number of studies clustered just above zero and a right tail, but no left tail. I think they're arguing that this is because the left side of the distribution is unpublished, and without knowing what it looks like, you can't come to a conclusion.
6gvONxR4sf7o 5y ago
Picture a perfect bell curve where the whole left half has been chopped off. If you had an a priori reason to believe it’s a bell curve, then it’s easy to spot the fact that the left half has been chopped off, and easy to spot where the mean would have been.

paulpauper 5y ago

I think it's understandable why the lead-crime hypothesis was/is so popular, because it it's an alternative to the hypothesis that increased incarceration and abortion reduced crime, which, politically, are less popular. It's more politically correct to blame lead poisoning than insufficient policing.

pasabagi 5y ago
Well, crime went down worldwide, whereas abortion and incarceration only went up in the US.
- kube-system 5y ago
  This is exactly why I think environmental, economic, and entertainment factors are the most likely, as they cross political borders. Everyone is always looking for a political angle, but while everyone is arguing over the efficacy of their team’s favorite crime policies, the answer is probably: give every restless teenager an Xbox and some macaroni and cheese.
  - jopsen 5y ago
    Yeah, cultural changes and access to entertainment might be the simplest answer :)
nwah1 5y ago
There's at least 16 hypotheses and none of them are that popular. In fact, most people are unlikely to even know that crime has been on a downward trend at all. The lead hypothesis has not been debunked, and if you read the article in the OP you'll find a number of unanswered questions. https://www.vox.com/2015/2/13/8032231/crime-drop https://www.vox.com/2015/2/13/8032231/crime-drop

deleted 5y ago

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tootahe45 5y ago

Lead poisoning = lower IQ & educational attainment poor education & lower IQ = locked out of the labor force and more likely to make bad decisions in life not rocket science.

jopsen 5y ago
Yeah, maybe.. but like the blog post says: > Nor are they the kind of study where you round up a hundred undergraduates and perform an experiment on them. Do we have good clinical evidence showing: lead = lower IQ? (I'm guessing nobody volunteered for lead poisoning). Thing is that crime reduction could be cultural, or simple widespread video games :) (Maybe it's a bit everything, and lead probably isn't the only environmental improvement we've made)

adenozine 5y ago

Would this not just be correlated with areas of poverty? Typically those areas haven't afforded new plumbing in the post-lead world thus far...

paleotrope 5y ago
The lead here was the lead used in leaded gasoline. It was lead in the air.

lamebitches 5y ago

Covid is a bio-weapon. Fauci is the dealer.

jl6 5y ago

It's astonishing to me that any large scale population study can ever prove anything, given how incredibly complex and unique peoples' lives are, and how many confounding factors may play a part at some point in those lives over many years.

unparagoned 5y ago
Well scientists don’t just rely on them. They would use them as just part of the puzzle. Do we known the mechanism, can we do causal animal experiments and then is there a correlation in humans.

hristov 5y ago

The lead-crime hypothesis is almost certainly true but the mass media reaction to it just shows how much is wrong with our society. First of all, the lead-crime hypothesis is good news. It is great to realize that small entirely achievable environmental changes can cause such marked improvement in wellbeing in people's lives. But for some reason it has not been accepted as good news by the mass media. And then you have papers like the one discussed by the article that try to debunk the theory on absolutely ridiculous grounds. (You see there are no studies disproving this theory therefore there must be studies disproving this theory, therefore this theory is wrong. What a bunch of BS!) So why is the lead crime hypothesis treated so negatively by our elites? Perhaps to avoid another round of massive litigation. Perhaps to prevent people from finding other ways other pollution can affect people's behavior and thus prevent the banning of other substances and other rounds of massive litigation. Or perhaps to preserve an image key in international culture -- the violent city youth.

Gauge_Irrahphe 5y ago
That's just wishful thinking. The costs on health could be massive if lead is essential. (and it very likely is)
jhbadger 5y ago
Another possibility is that people just don't like such reductive explanations of human behavior. It's easier to say, well, violent youth is a product of society somehow and it's too hard to come up with a concrete explanation.
- Hammershaft 5y ago
  I think many people are uncomfortable with the idea that a chemical or unknown environmental change can cause such marked changes in human behavior.
  - michaelmrose 5y ago
    To be even more accurate the older folks are uncomfortable with provable allegations that they are brain damaged.

coding123 5y ago

Its the cameras.

alex_young 5y ago

Isn't this more of a critique of meta-analysis itself? It seems pretty suspect to take a collection of published studies with different populations and different criteria and derive any meaningful meta product from them, especially since we know most research is never actually published.