I've been following with fascination the debate in the U.S. about the relationship between crime rates and early childhood lead exposure. One of my favorite bloggers, Kevin Drum, recently wrote a fantastic piece for Mother Jones arguing that America saw dropping crimes rates in the 1990s in part because the U.S. banned leaded gasoline in the 1970s, saving an entire generation of children from exposure to lead, a fiercely potent neurotoxin which permanently lowers intelligence and disrupts impulse control in children. Read it here. Drum reports on reactions to the article and takes on critics here.
And now for Europe:
Here's the latest crime news from the Guardian:
There has been a surprise 8% drop in crime across England and Wales, according to official figures, suggesting the long-term decline in crime since the mid-1990s has resumed.
As near as I can tell, crime declines are always a surprise to the folks who look for answers solely in social trends. But Britain's continuing decline isn't a surprise to everyone. Europe adopted unleaded gasoline in the mid-80s, and EU countries all showed drops in lead emissions in subsequent years. In Britain, lead emissions began to decline about a decade later than the United States, but they made up some of that gap via a much steeper drop. So, to the extent that the crime decline is a function of less lead exposure among children, they're about five years or so behind us. This means they probably still have a few years of crime decline ahead of them.
So, you might be wondering, if Germany began seriously reducing lead emissions in the the mid-1980s, what impact might that have had on teenage criminality in the late 1990s, when children born in the mid-1980s became adolescents? Here's the relevant graph for Germany, from this source (g, .pdf):
The top line shows total criminality, the middle line criminality among German adolescents, and the bottom line among immigrants. Interesting, isn't it? The much smaller decrease you see among non-German offenders could well be explained by the fact that some percentage of them probably did not grow up in Germany.
Of course, the standard caveats apply that correlation is not causation, other factors are at work (especially the crime increase following reunification), etc.. But if you want to be convinced that lead exposure is a powerful (though, of course, not the only) explanatory factor, read Drum's piece -- and, more importantly, the studies it links to.
If this theory holds, it has to be one of the best pieces of news in a long time: because of a wise policy choice made decades ago, we will enjoy less crime -- and less of all the social ills and expense it causes -- for years to come. Kind of restores your faith in humanity, doesn't it?