A few years ago a friend of mine was putting together a syllabus for a history course on the 1980's, and was soliciting ideas for topics to discuss. He got a lot of political ideas -- the Reagan revolution, the mobilization of the Christian Right, anti-Communism -- and a lot of "fun" cultural things to comment on, like New Wave, for instance. I tried to think of something that was important to people's everyday lives but that was a bit "unsexy," and what I came up with was the spike in urban crime that sometimes is associated with crack or gangs or whatever.
Then I decided to read up a bit on it, and the more I read, the more I discovered just how big, and how inexplicable, this crime wave was. Violent crime in US cities began a significant rise in the 1960's, peaking in around 1991. By that time, rates of murder, rape, and robbery had increased to 4 and 5 times what they were in the '50's. And then the Times Square ball dropped on 1992, and just like that, the crime rate stopped and then began a precipitous fall. By 2012, we had a crime rate similar to what we had in Nixon's first term. Violent crime in NYC, for example, is down 75% from its 1991 peak.
The effects of that crest and ebb must have affected us in significant ways, even if we're too close to it see. The trend of gentrification of old city neighborhoods, the population declines of major cities, suburban sprawl, the continued concentration of African Americans in urban ghettos and higher rates of incarceration, all could possibly be connected to this trend. Imagine what a war zone Washington, DC or inner city Atlanta looked like in 1991, and that only 20 years later, those are hot spots for young, educated couples looking for a cool place to live.
There are two aspects of this tremendous transition in our social landscape that I find absolutely baffling. One is that not only has it gone largely unnoticed, but most people actually believe America is getting more dangerous. The second puzzler is that such a sea change occurred with no obvious cause. Lots of people have ideas on why it might have happened, but there's no clear cause we can point to for the fact that cities became 4 to 5 times more violent between 1960 and 1990, and then returned to the same rates as rural areas.
Kevin Drum thinks he may have hit upon the answer, and it's shockingly mundane: lead exposure from leaded gasoline emissions. I would really have expected a more sociological answer, but his case seems quite strong to me.