There is an interesting article by Steven Pinker at Edge about the declining instinct towards violence.
In the decade of Darfur and Iraq, and shortly after the century of Stalin, Hitler, and Mao, the claim that violence has been diminishing may seem somewhere between hallucinatory and obscene. Yet recent studies that seek to quantify the historical ebb and flow of violence point to exactly that conclusion. - A History of Violence
I’d say we aren’t as violent. I haven’t killed anything since last night (a bug), and this very morning I drove to a building, obeying traffic laws along the way, and handed someone some green paper with a mutually agreed-upon value in exchange for food. Right now I’m in another building, using my skills in exchange for more tokens of value, which I can convert into green paper when I’d like. It’s hard to create that sort of framework without a declining instinct towards violence.
However, it’s also clear that when we choose to be violent, we have the capability of being much more efficient about it, thanks to the organizational and technological benefits of the same social frameworks that help reduce our tendency towards it.