I have to wonder if Mercury levels should be considered, as well.
ETA: Link to column: Does no more lead in gasoline = less violent crime? - The Straight Dope
Edit: realize OP not actually asking thread title question
Presumably this is the thread in question.
ETA: I don’t see the harm in looking at all of the data and trying to correlate cause and effect. I have to admit I blew off the lead in gas explanation when I first skimmed it, but the lead in paint angle certainly bears looking into.
That’s an odd argument XT: lead exposure is lead exposure.
Great column by Cecil: it really pulls the evidence together in a concise manner. What I like about the hypothesis is the diverse sources of support: it draws on 2 peaks of lead exposure, 2 peaks of crime, multiple geographic patterns, direct clinical evidence and even blood samples of inmates.
I thought I spotted a typo though: The role of lead at the time was conjectural, but he thought it bore looking into. “Worth” looking into, right? Or maybe worth boring/drilling into.
“Bears looking into” means worth of looking into. Bore is the past tense of “to bear,” isn’t it?
I believe XT’s argument is valid. Heavy metal poisoning is caused by heavy metals, like lead or mercury or even gold. I wonder if communities downwind of cement plants have elevated crime rates. Mercury occurs naturally in the limestone used to produce cement, and it’s driven off in the kiln and released to the environment. More research is needed to bare any truth to this.
before the argument can be considered anything other than a specious correlation, it would have to be shown that having lead gasoline in contained tanks of automobiles, lawn mowers, etc. actually constitutes exposure to lead. Show that this can be true than the theory gains credence. Without it… it’s still just a correlation.
The lead passes through the combustion chamber and then out into the environment. It’s oxidized at this point, but still lead. From here, it’s metabolized into brain tissue which has been linked to the entire alphabet of mental disorders. The logic is sound, it just remains to be disproved that Bill Bratton, long period economic progress or just simply not enforcing DWB laws had nothing to do with the drop in crime rates.
Agreeing with watchwolf49, the lead in fuel comes out in the exhaust, as fumes that can be breathed in. Cecil’s point is that the correlation bears looking into. Disagreeing slightly with watchwolf49, the economy, gun laws, social norms (e.g., the anti-government protests of the 60s), etc obviously do affect the crime rate. No one suggests that absence of lead will cause all crime to disappear. So, no one can prove that these things “had nothing to do with the drop in crime rate.” The question is whether there was an additional on-top-of causation, and that needs more investigation.
Analogy: radiation is highly correlated to cancer, but it’s not the only cause. It would have been silly back in then to say not to bother to investigate radiation, until “disproving that smoking has nothing to do with cancer.”
I do know that there was one mayor of Chicago (I don’t recall who, it was after the first Daley) who re-defined what constituted “violent crime” so that he could claim the crime rate went down under his administration.
Much of the lead exposure data which researchers, and we, studied was from air monitoring.
(Cecil’s point is looking into that may bare the correlation.)
The lead in exhaust also settles out onto the ground. Small children – you know, the ones who put everything they can into their mouths, and play in the dirt constantly – then ingest the lead, one way or another. And of course, it’s small children who are most affected by lead poisoning.
I feel like the lead-crime correlation is in very real danger of falling into a false cause fallacy.
It’s been well-established (honestly there was such a plethora of data, i can just randomly link something from google) that poverty and crime have a direct relationship. Let’s go with Becker’s Crime and Punishment
In general, both crime and lead paint are more prevalent in poor neighborhoods and households. I’d love to believe it was the paint and not all the societal disadvantages associated with the poverty.
This isn’t to say that there can’t be a valid link between leaded-gasoline, lead-based paint, and criminal behavior, but rather to discredit the studies that were referenced that are attempting to create a link between today’s crime rate in today’s poor areas that still have lead paint. There’s no control group where an area is affluent AND has lead paint, and they make no attempt to mention the areas (like new construction, low income housing) where crime is rampant and there is no lead paint.
Also, I just happened across this site today for the first time and I’ve gone down the rabbit hole for a couple hours. Hi. 
You’re right that it’s not definitive, but consider this: Poor areas still exist. If crime has gone down, despite the continued prevalence of poverty, then there must be more to it than simply poor=crime.
Powers &8^]
I think Atavis and Powers both make good points. Cecil’s (or Mother Jones’) argument remains compelling though since the lead exposure data, as reported, seems to correlate to crime in a much larger region than could be explained by poverty alone.
The article makes me think of lead exposure in the Roman empire. They used lead pipes; they drank from lead goblets. They had no idea what they were doing- lead was added to wine as a sweetener. Sweetener! And it seems that the more affluent a Roman was, the more chances they had to be exposed to lead. The result? Rampant mayhem, crucifixions, Coliseums, torture, regicide and on and on. Admittedly I’d need some support turning this point into data that buttresses the ‘lead exposure causes crime’ argument.
Unfortunately I think TubaDiva got a rather large prenatal dose of gas lead.
Gold poisoning? I don’t think so.
MODERATOR NOTE: Askance’s comment was response to a troll, whose post is deleted, so now makes no sense. Nothing to see here, just read on.