[chmod775]

Not to mention that there seemed to be surprisingly little lethal human-on-human violence prior to the Neolithic period. From what we know, lethal violence rose sharply as soon as people started settling down, amassing possessions, and forming more elobrate social hierachies.

Lethal is an important qualifier here, because even skeletons from before that priod routinely show signs of human-on-human violence - it just wasn't what killed them.

Which makes sense: To this very day most killing is done for material gain or when fighting over land. Without these reasons, we'd likely be a more peaceful species.