Turns out the answer was already out there. Guess what it turns out to be? Leaded gasoline.
The studies behind it are solid and cross-studied across the planet. Children exposed to lead have lowered IQs and become more impulsive in adulthood. When leaded gasoline was introduced, the children that would inhale the exhaust would later disproportionately become criminals. When it was banned, the crime fell, with the same lag time of about 23 years. Never would have thought it would be something like this but I'm thoroughly convinced that's the explanation:
http://www.motherjones.com/environment/2...k-gasoline
The studies behind it are solid and cross-studied across the planet. Children exposed to lead have lowered IQs and become more impulsive in adulthood. When leaded gasoline was introduced, the children that would inhale the exhaust would later disproportionately become criminals. When it was banned, the crime fell, with the same lag time of about 23 years. Never would have thought it would be something like this but I'm thoroughly convinced that's the explanation:
http://www.motherjones.com/environment/2...k-gasoline