A difference in degree, not of kind. The societies probably informed each other through trade. Horses were domesticated around this time and were used as pack a

A difference in degree, not of kind. The societies probably informed each other through trade. Horses were domesticated around this time and were used as pack animals even if they weren't yet being ridden. Aristocracies would have traded ideas along with goods. Advances in governing might have communicated themselves across the whole globe in a few hundred years, maybe even shorter. This is a blink of an eye on the historical time frame. We really shouldn't underestimate the capabilities of Neolithic peoples.