I’m fascinated at the moment by the question of what is causing the decline in violent crime. This is a question that doesn’t get as much attention as it should. If crime rates all over the developed world were exploding it would be a huge topic of debate. The fact that they’re collapsing isn’t exactly a secret, but certainly does not get as much attention.
The interesting thing is we really don’t know why this is happening. There are lots of pet theories out there: Changes in policing methods, demographic shifts, drug popularity, abortion. This article makes the case for the phase out of lead in petrol. It’s very interesting and I would recommend a read. The Australian part of the case is particularly interesting, given that we were apparently trailing most of the rest of the rich world quite badly on this. The Mother Jones blog site is promising back up information that will further bolster the case.
Almost certainly all of these are contributing factors, but disentangling how much each contributes is pretty hard. It may well be that some are trivial. This matters, because if we knew what worked most of them could be stepped up to a greater extent.
Impressive as the Mother Jones article is, I’m not entirely convinced. There are three reasons for this. Firstly, I’d really like to believe this explanation. Of all those put out there it is the one that is most in keeping with the world view of lefty environmentalists. And as I have argued before, when you see some research that appears to bolster your world view its best to take it with more grains of salt than when you don’t have a stake in the issue.
The second reason is simply that I’ve seen other cases before that seemed really convincing, and then turned out to be overblown. I was pretty impressed with the Levitt/Donohue argument on Roe Versus Wade when it first came out, but it now seems that, while this may well be a contributing factor, its less of the story than first appeared.
But there is a third factor, which is perhaps the most interesting. Violent crime soared in the 60s and 70s, but there is plenty of evidence that this was an aberration. Murder rates in Europe and North America have been declining for centuries, with occasional flicks upwards. Steven Pinker has attracted much attention by claiming the trend extends back to the development of agriculture. Both this claim, and his explanations appear fairly dubious, but credit to him for at least bringing to wider attention the trend since the middle ages.
Even at the peak of 20th Century crime rates they were trivial compared to centuries before. In one sense this further bolsters the idea that the rise was driven by a one off factor such as lead ingestion by young children, and as the effect of this passes violent crime rates will return to “normal”. But the larger question remains. Why is normal, as taken in 1950 or 2010 so much lower than that in 1550 or 1710? As far as I can tell we don’t have a good answer. None of those offered in the first link in the paragraph above seem to offer a convincing explanation.
Besides being intellectually fascinating I think the question is worth posing for reasons other than working out how to reduce crime. For one thing, its an antidote to hopelessness about other apparently intractable problems. If we can make such inroads, without even knowing how we do it, on a problem that has bedevilled humanity probably since we first were human its hard to believe the struggle to save the biosphere is already lost.
Moreover, asking the question brings to attention the fact that this is actually occurring, and something of which most people are not aware. The rarer violent crime becomes the more it gets reported, and the more people become convinced the problem is getting worse. This leads to people failing to fully engage with society, because they don’t feel safe. It also leads to more support for political parties willing to offer “tough on crime” policies that manifestly don’t help, and may even make things worse.
Finally, I like considering this question because I think that there is a fair chance that whatever is causing the decline in crime will turn out to be something that is good for other reasons. The abolition of lead in petrol would have been worth doing even if there was no effect on crime at all. Yet it had to overcome fierce resistance from the same people now opposing action on Climate Change (not just the fossil fuel industry, but also reflexive right-wingers fight for the “right” to pollute). Finding something like this at the core of one of the biggest stories of the millennium would be sweet indeed.