America’s incarceration rate is in decline

This is interesting. I don't know why it's happening. However, this book deserves a mention: https://en.wikipedia.org/wiki/The_Better_Angels_of_Our_Natur... . It shares statistics on how violence has been decreasing throughout the history of humanity.

as a followup to that (excellent) book, here's Barry Glassner - A Culture of Fear. The Better Angels of Our Nature talks about how violence has always been declining. A Culture of Fear talks about how the rate of that decline has been increasing since the 90s but people actually perceive things as becoming more dangerous rather than less, and attempts to come up with an answer as to why that may be the case.

The most obvious answer is large-scale media. I can learn about a shooting on the other side of the country within hours of it happening, and think "that could happen where I am". Likewise with any other news, which by definition is about out-of-the-ordinary events. There's more news about violence because there's more news, not because there's more violence, but it feels like there's more violence.

"if it bleeds, it leads" is (or was, i'm old) a common saying regarding the news media. It may be that there is more news that scares us because scaring us is profitable

20 century features pretty much largest genocides ever. Multiple of them. And in addition, things that we do not count as genocides, but still involved deliberate killing of millions.

That particular book was criticized by historians a lot.

Maybe that violence is just better organized now. Personal violence is declining (assault, murder, ...), but not organized violence (war, genocide, ...).

I don't know how good that book actually is, but I read acoup blog and it criticizes that book very often. Instead it recommends readers to Azar Gat's War in Human Civilization instead https://www.amazon.com/War-Human-Civilization-Azar-Gat/dp/01...

Piling onto this, humans have both recency and frequency biases that, combined with the attention-as-currency news industry, tend to lead to an increase in the perceived danger of violent crime that's entirely disconnected from the actual statistical danger of violent crime. You hear about more crimes, you hear about each crime more often, and your estimate of how much crime there actually is increases.

This has often been attributed to banning lead additives from gasoline.