We have seen objects moving great distances within the Plains and coming onto the grasslands from much of the North American continent more and more over time, albeit in small numbers. However, objects move because people move them, and people rarely move the kinds of small, durable items that preserve in the archaeological record in isolation. Instead, they usually move them along with a variety of other things, including nondurable things like food. That things move with people also means that those people move, and that their knowledge – language, customs, technical information, ideology – moves, too. But objects, people, and ideas do not necessarily move together in equal proportion or with equal effect.