An Astounding Explanation for Why Big Cities Are More Dangerous Than Small Ones

For decades, researchers have hunted for an explanation for why big cities have been more prone to violent crime than small ones. A new hypothesis may offer a surprising answer, and prove that big cities aren't inherently much more dangerous.
Jim Pickerell / Wikimedia Commons

Researchers have offered several potential explanations for historically higher rates of violent crime in big cities: from the idea that there's more valuable stuff to steal in big cities to the rise of the crack epidemic. Even if other potential reasons strike you, you probably haven't considered a new persuasive hypothesis: exposure to gasoline lead. In an article for Mother Jones and in a follow-up blog piece, Kevin Drum examines the connection between lead exposure and crime.

"In a nutshell, the lead-crime hypothesis is simple: exposure to gasoline lead in small children produces heightened aggressive tendencies. When an entire generation of children was exposed to lead in the 40s, 50s, and 60s, thanks to the boom in auto sales after World War II, it led to a huge rise in violent crime when the children grew up in the 60s, 70s, and 80s. The more lead they were exposed to, the more crime you got."

"So where did we see the most exposure to gasoline lead? Answer: in places with the densest concentration of automobiles. And that's in the inner core of big cities. In the early 60s, big cities had double the ambient air lead levels of mid-size cities, which in turn had air lead levels 40 percent higher than small cities. (Nevin, p. 316.) So if lead exposure produces a rise in crime, you'd expect to see a bigger rise in big cities than in small ones. Over time, big cities would become increasingly more dangerous than small ones."

"Likewise, when lead was removed from gasoline, and children started to grow up normally, you'd expect to see a bigger crime decrease in big cities. Over time, crime rates would start to converge."

"And that's exactly what we see in the data."

"Only gasoline lead," concludes Drum in his article, "with its dramatic rise and fall following World War II, can explain the equally dramatic rise and fall in violent crime."

Full Story: Are Big Cities More Dangerous Than Small Ones?




I'm sure the correlation between leaded gas and violent crime is correct, but to say that "only gasoline lead . . . can EXPLAIN the dramatic rise and fall in violent crime" is way over the top.

IF there is any explanatory truth there, it is incumbent on the people making this claim to show it.

OTOH, the NAS wrote a multi-volume study of causes of violent crime in cities more than a decade ago. I don't recall leaded gas being cited as a cause of VC.

Remember: Correlation is not causation.

Irvin Dawid's picture

Oakland lead higher than, say, across the Bay

I know Mother Jones was looking at the stats from an historical basis, but to bring it current, the SF Chronicle just reported on crime in the Bay Area's largest cities (>100,000), and it did not look good for the 3 largest (Oak, SF, SJ):

"The region's 15 biggest cities saw 310 homicides last year, according to interviews with city officials. That was up from the 275 homicides in 2011 and 248 in 2010 that the cities reported to the state Department of Justice and the FBI.

The increase, however, was driven almost entirely by the region's three largest cities, San Jose, San Francisco and Oakland, where killings rose 52 percent in two years.
Taken together, the other dozen cities had 24 percent fewer homicides over the same period."

Does MJ have any other theories?

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