Early Neolithic Britons had a one in 20 chance of suffering a skull
fracture at the hands of someone else and a one in 50 chance of dying from their
injuries. ...Blunt instruments such as clubs were responsible for most of the
Rick Schulting of Queen's University Belfast and Michael Wysocki from
the University of Central Lancashire looked at 350 skulls spanning the period
from 4000 BC to 3200 BC.
"We generally think of Neolithic people as living
peaceful lives - they were busy looking after cereal crops and rearing
livestock," Mr Wysocki told the BBC News website.
Well, I guess that's what they get for turning to agriculture and sky god religions. Just a few thousands of years before, when everyone hunted & gathered and worshipped the Great Goddess (which worship is proven by their having scratched chevrons into rocks), human nature was completely different and no one hit people in the head with clubs at all.