Lead

Dylan Matthews’ list of ways to reduce violence without gun control starts with one that cannot be stated strongly enough. The decline of lead exposure over the past decades is probably the single biggest reason why violent crime has dropped so much since the 1970s:

None of the above. The real answer, it’s now becoming clear, is lead. In the 1970s, the environmental movement succeeded in getting lead out of gasoline and household paint, and the result has been smarter, less violent kids. Economist Rick Nevin has found that, if you add a 23-year lag, variations in lead exposure explain 90 percent of the variation in crime rates in the United States.

Jessica Wolpaw Reyes, an economist at the Amherst College, found that declining lead exposure caused a 56 percent decline in crime from 1992 to 2002, a decline that was reversed by other factors to leave the actual decline at 34 percent over that period. Wolpe Reyes has also found significant effects on childhood delinquency and academic performance. The correlations are simply staggering.

This is one reason why I focus so much on environmental exposure and working conditions in my writing. These issues not only affect people in the short-term, but they are absolutely central to solving larger societal problems, including violence.