TL;DR: Lead levels and violent crime are incredibly strongly correlated. This is much higher than traditional correlations between violent crime based on demographic stats (living in a city, being black, or being a Southerner all increase your chances of both committing or being a victim of violent crime).
This holds true at the country level, the state level, the city level, and the neighborhood level, and the evidence is extremely strong.
So people don’t cause crime; lead causes crime.
It’s sort of like the idea of replacement level in major sports. The quality of play may go up or down over time, but we mostly judge people in relation to their peers and what we expect the average person would do.
So someone in a poor neighborhood with not great job prospects and lots of environmental, with an alcoholic or abusive single parent, is not primed for success, but might still find athletics or music or a school subject to be a motivating passion, and if there are social services around to provide a ladder out, some number of people will take advantage of it because a stable life with wealth gained through ‘legitimate’ means is more secure and easily defended than wealth gained beyond what’s sanctioned by the society holding a monopoly on violent force. If you can make $120,000 per year as a dentist, over time there’s a lot less of a work involved acquiring and protecting your money versus selling bootleg DVDs or operating a prostitution business.
If you have a chemical that makes the average person more aggressive, those in situations where they have lots of ladders or are already several floors up will still tend to be OK. But those with lots of pressures to be violent already now physically lack a last defense against it. Lead exposure in children is worse than, say, testosterone because—in addition to making people less inhibited to a violent response—it makes them less coordinated and cognitively developed. So more people who might have found success in academics or entertainment aren’t going to have a productive outlet open to them there, either.
Again, this all the replacement-level person. People can still do well in spite of all those negative factors or fail with every advantage, but on average, crime is always a product of larger forces.
So if this is a better explanation of the variance in crime than race, could it also be a better explanation than “systemic racism”?
Like, if black people tend to live in places with greater lead exposure, and that has some significant behavioral consequences, wouldn’t you expect that to play out professionally? And explains why foreigners and Asian actually do really well?
Well, the trouble is that exposure to lead is going to be a symptom of systemic racism, in places like Chicago. Then if that exposure makes someone more violent or have cognitive impairment, that’s on top of everything else pushing and pulling on them in their lives.
Someone with lead exposure as a child but who wasn’t exposed to excessive alcohol in utero is (I think) going to be less impaired than someone with fetal alcohol disorder but no lead. That’s one factor out of an almost limitless number of them, and with each one when you study it you’re saying, ‘all things being equal’.
Systemic racism is part of why ‘all things being equal’ can’t be assumed. You’re going to have more poverty, lower quality schools, less law enforcement concern for communities but more police violence in those communities, and many other negative contributing factors, but also I expect you’re going to have more exposure to lead because marginalized populations are never considered as high a priority even when negative health impacts have been identified (compare the reaction to the lead poisoning of children in Flint, Mich., to what would happen if the same thing occurred in Greenwich, Conn.; government officials wouldn’t treat it as anything but an emergency from the beginning). Being exposed to lead as a child when that person has many other things going for them might not be enough to push them into the territory of low academic achievement, few marketable skills, and devoted criminality.
Finally, you have to think about how we define crime. Lead exposure might make people in the dominant class more violent, so that could explain lynchings or excessive police brutality. But those violent acts wouldn’t be criminal, even if they involve someone being killed, depending on who that person is.
Systemic racism is just extremely pervasive in that way.
But where does “systemic racism” end, and the consequences of a population of people who’s behaviors have been significantly impacted by lead poisoning begin?
Like, it used to be that everyone thought people in the rural south were just really fucking dumb and gave them all sorts of grief for it—and they were right because people in the South were plagued by hookworm.
Is that systemic bias against Southerners, or people just responding to behaviors and cognitive impairment as a result of a pathogen?
The world is complex and people don’t enter the world fully formed. ‘Why does this cake taste bad (or good)?’ is a question not just of ingredients but the order they were combined and even the exact conditions of their combination.
The pathogen is an ingredient; lead is an ingredient; the availability of chemical substances like alcohol or meth might be an ingredient, but I’d argue the system set up to reward some and punish others, implicitly and explicitly, is akin to the baking that all ingredients will be subject to.
Before leaded paint and gasoline, there was still Jim Crow, segregated schools of inferior quality, chaingangs, and the sharecropping system.
‘Where does it end?’ — well, it basically doesn’t. But some things can make it better or worse.