That whole myth about hunter-gatherers being peaceful and non-violent probably got its start because hunter-gatherers tend not to be as good at organized warfare as the Germans.
Homicide is an act of disorganized impulsive passion; warfare is an act of organized dispassion; the two are inverse of each other. Thus we see the highest homicide rates in the world’s least developed countries, and the lowest rates in its most developed countries.
Note that it is not an absolutely perfect correlation; many Latin American or Caribbean countries have higher homicide rates than even less-developed countries in Africa, but broadly speaking, the pinks and reds are poorer than the blues. (Russia excepted, ‘cuz Russia.)
Also, as you may recall:
Countries involved in the world’s biggest wars:
WWI:
Nuclear stockpiles or programs by country:
(South Africa used to have nukes, but they got rid of them before the end of Apartheid.)
Here’s another graph that makes the size of the arsenals clear:
And here’s another graph that says about the same thing, but is a wonderful example of how to display data:
I’m pretty sure this graph means we’re all going to die.
And likewise, space programs by country:
Also a nicely done graphic.
You might have heard about India’s space program:
But have you heard of the Congolese space program?
To be fair, it’s more “One guy with a rocket-building hobby” than a real space program, but I understand where he’s coming from. Rockets are cool.
The point of all of these maps and graphs is that homicide rates tend to be highest, both today and throughout history, in the places with the lowest levels of social organization/complexity.
Even in our own society, convicted criminals are overwhelmingly lacking in the ability to handle complexity. It looks like they aren’t really all that much more retarded (note: PDF) than the general population (the truly intellectually impaired are often pretty highly supervised and lack the ability to execute many crimes, but are often victims of violence,) but they are drawn disproportionately from the dumber half.
According to respondents in the AR15.com forum thread “Cops and Lawyers – What percent of criminals/clients are retarded?” (Note: I know nothing about this forum or its reliability)
“Not retarded per se. My personal experience is most criminals stopped developing emotionally at about 3 or 4. They live life for the moment, think only of themselves, have no impulse control, can’t control their emotions, throw temper tantrums when they don’t get their way, can’t think past the next 10 minutes, don’t understand consequence, etc……. They are basically little children in adult bodies. Of course, most 3 or 4 year olds are better behaved than the average criminal, but you get the point.”
“I found that better than 90% of them were functionally illiterate, so when they say reading is fundamental, they aren’t kidding!”