People sometimes ask me for examples of where I’ve changed my mind. One example is lead. I used to be skeptical of the claims that lead exposure had major effects on behavior and intelligence. I was exposed to lots of lead when I was young, much more than most other kids I knew. And I didn’t notice any ill effects.

Of course that sort of anecdotal evidence is not very persuasive, and I’ve come around to the view that lead exposure probably did do a lot of damage to earlier generations.

Noah Smith has an excellent twitter thread discussing the amazing decline in violence since the early 1990s. Some of his commenters mention the internet, but that can’t be the whole story. Much of the decline in violence occurred before 2000. I’m more persuaded by Smith’s pointing to the reduction of lead exposure. While this theory seemed implausible to me when I first heard it, today it seems like the explanation that best fits the facts.

As far as property crime, I think there are other factors at work. In 1990, I used to get $500 each time I went to an ATM machine, which I spent gradually over a few weeks. So on any given day I was usually carrying roughly $300 in my wallet. Now I tend to carry about $40 and I use credit cards for most things.

I used to worry that my expensive TV might be stolen by a burglar.  By 2017, that 52-inch Samsung TV was almost worthless, so much so that when I got a new TV last year I simply gave the Samsung to the deliveryman. I worry far less about theft than when I was in college, when I feared that my Pioneer stereo system might be stolen. The market for used electronics is no longer very robust. The same is true of antique furniture, and many other items. We are moving away from an economy based on things, and toward one based on experiences. The exception is real estate, but that can’t be easily stolen.  (Are iPhones another exception?)

So that’s my theory. Less violent crime because of the removal of lead, and less property crime because there is less stuff worth stealing.

PS. The Straussian reading of this post is me bragging about how spectacular a human specimen I could have been if not for all of that lead I ingested. As Simler and Hanson tell us, there’s always a selfish hidden motive for even idealistic statements, such as “I was wrong.”   🙂

PPS.  I first noticed the strange calm and politeness of young people in the early 2000s, when I went to a rock concert after a long hiatus.  There was no longer the feeling in the air of imminent violence.  Everyone was so . . . chill.

And yet, the Economist points out that this amazing reduction is violence is associated with a move toward sheltering our children from the dangerous outdoors:

When I was a kid, we were out and about all the time, playing with our friends, in and out of each other’s houses, sandwich in pocket, making our own entertainment. Our parents hardly saw us from morning to night. We didn’t have much stuff, but we came and went as we liked and had lots of adventures.” This is roughly what you will hear if you ask anyone over 30 about their childhood in a rich country. The adventures were usually of a homely kind, more Winnie the Pooh than Star Wars, but the freedom and the companionship were real.

These changes also help me to better understand the “reactionary impulse”.  Even when changes are clearly for the good (less violence), my gut instinct is to miss the good old days.  I try to push back against that impulse when considering social change.