Based on centuries of observed behavior it is apparent that modern man walked out of Africa...and left the stupid behind.
In this case, you likely have one tribal unit of a dozen folks, led by ‘Larry’, who got peeved with living conditions, the heat, and continued warfare between other tribes (which is obvious even today).
pepsionice: "In this case, you likely have one tribal unit of a dozen folks, led by ‘Larry’, who got peeved with living conditions, the heat, and continued warfare between other tribes (which is obvious even today)."
Oh, we can do better than that...
Our ancestors who left Africa were the losers, they got beat up by bigger, faster, smarter & meaner rivals and ran off with their "tails" between thier legs.
But then something happened -- in their long travels across the globe, those who weren't big enough, fast enough, smart enough, mean enough (and should I add: good looking enough?), they didn't make it and so, on average, the exiled tribes & clans slowly increased in those qualities.
Today of course everything is reversed, but that's a whole different story...