So, when 1 pop meets a smaller one (90% right-handers).
But WHY Right-Handed for Northern Hemisphere?
Sun rays come from south. There's a disadvantage of hunting or facing an opponent against the sun so northerners need to be able to throw farther a rock or spear. So, by Coriolis effect, if you throw right, the spinning of earth is on your side.
- A chimp throws at 20mph, humans at 60mph.
- Chimps are 66% right-handed compared to humans: 90%