[Scroopy Noopers]

Originally Posted by JohnnyB

I wonder what caused the two decades of growth in NHL fighting, and what changed from the late eighties into the early nineties. That's a period before my time to have perspective on

https://en.m.wikipedia.org/wiki/Lead–crime_hypothesis

Proponents of the lead–crime hypothesis argue that the removal of lead additives from motor fuel, and the consequent decline in children's lead exposure, explains the fall in crime rates in the United States beginning in the 1990s.