Environmental deterministic are group of people who believe that the development of the environment will heavily influence the development of culture in it.
When we reify a certain concept, we transform an abstract concept into a more concrete one as an effort to understand it.
When we treat culture as a real force, we consider it as a concrete object that can be shaped by various factors around it. Which is why environmental deterministic tend to Reify culture more than others group of people.
According to one theory by British archaeologist Mortimer Wheeler, a nomadic, Indo-European tribe, called the Aryans, suddenly overwhelmed and conquered the Indus River Valley.