January 3, 2013

"America's Real Criminal Element: Lead"

There are dozens of competing theories about the causes of crime. But only one fits perfectly with the data, claims a bold new investigative report. And that is lead poisoning.

"An astonishing body of evidence" on the international, national, local and even individual levels shows that much of the rise and fall of violent crime over the past half century is attributable to atmospheric lead from leaded gasoline popular from the 1940s through 1970s, according to the report by Kevin Drum in the current issue of Mother Jones magazine.

The theory has been around for about a decade, but it has been marginalized by criminologists, according to Drum, a political blogger.

As many of you know, childhood lead exposure has been linked to a permanent loss of gray matter in the prefrontal cortex, which controls executive functioning (emotional regulation, impulse control, attention, verbal reasoning, and mental flexibility). Lead also degrades the myelin that is necessary for efficient communication among neurons. Drum calls this a "double whammy":

"[Lead] impairs specific parts of the brain responsible for executive functions and it impairs the communication channels between these parts of the brain.... Even moderately high levels of lead exposure are associated with aggressivity, impulsivity, ADHD, and lower IQ. And right there, you've practically defined the profile of a violent young offender."

Drum isn't arguing that lead exposure automatically turns youngsters into criminal automatons. Rather, he says, the neurological effects of lead pushed vulnerable youngsters who were "already on the margin" over the edge into crime.

"Once you understand that, it all becomes blindingly obvious. Of course massive lead exposure among children of the postwar era led to larger numbers of violent criminals in the '60s and beyond. And of course when that lead was removed in the '70s and '80s, the children of that generation lost those artificially heightened violent tendencies."

The leaded-gasoline hypothesis explains some other demographic features of crime, Drum asserts, such as the diminishment of urban-rural gaps in murder rates in recent decades.

Drum concludes with a spirited argument for government-funded programs to vanquish the remaining lead in soils and homes:

"We can either attack crime at its root by getting rid of the remaining lead in our environment, or we can continue our current policy of waiting 20 years and then locking up all the lead-poisoned kids who have turned into criminals. … Cleaning up the rest of the lead that remains in our environment could turn out to be the cheapest, most effective crime prevention tool we have. And we could start doing it tomorrow."

I'm not sure I'm completely sold on it, but it’s a fascinating thesis, and certainly worth reading. I’d love to hear blog readers' reactions

The piece, published today in the January/February 2013 issue of Mother Jones, is available HERE.


Unknown said...

What a fascinating investigative piece! Thanks for bringing it to my attention, Karen.

What strikes me most is how this strong research evidence was marginalized by the criminal justice community. Among the reasons Kevin Drum cites is purely political:

"Political conservatives want to blame the social upheaval of the '60s for the rise in crime that followed. Police unions have reasons for crediting its decline to an increase in the number of cops. Prison guards like the idea that increased incarceration is the answer. Drug warriors want the story to be about drug policy. If the actual answer turns out to be lead poisoning, they all lose a big pillar of support for their pet issue. And while lead abatement could be big business for contractors and builders, for some reason their trade groups have never taken it seriously."

We see that happening with evidence-based research in other forensic areas: if it causes a problem for the prosecution, then it is demonized and devalued.

Karen Franklin, Ph.D. said...


I agree that this was one of the most intriguing aspects of the report.


Cavall de Quer said...

But it principally affected male children?

Unknown said...

I don't think so. Teen pregnancy also peaked around the same time and has fallen dramatically since. There are probably other expressions of "bad decision making" that fit the thesis.