Remember though, that culture knowledge and ways can travel farther and faster than a migrating group of people. Knowledge, say of corn raising and all the attendant religious and social aspects that come with it, can be spread by just a very few pioneers, “missionaries” if you will.
Once a people are exposed to an aspect of a culture that is clearly useful, they can adopt it, and adapt to it, very quickly. For instance, nobody needed to spend much time teaching the Indians of the high plains the usefulness of mustangs before their whole cultures were revolutionized. Though they might have shared many identical aspects of the horse culture of the Mongolian steppe, they never needed to meet a Mongolian.
My two cents.
Oldplayer
(Choctaw)
I thought you brought up a good point about how cultural influences travel even faster then people. The networks of trails and roads that the Native people created across the country are an interesting testament to the importance of trade. Many highways follow those paths for to all people trade is important, along those Indian trails come thoughts with bits of soapstone, copper and obsidian. I think the extent of the traffic in goods and ideas was not fully realized by the Europeans. In the museum at the Hopewell National Historic Park in Ohio they display goods traded across the continent.