I Believe the answer is: Serial position effect
Serial position effect refers to a tendency among people to held the first and lest object of memory in higher regards compared to the one that placed in the middle. This happen because most people use the first and last objects in the list to mark and separate one set of memory with another.<span />
They changed the culture of the region by bringing weapons and horses that the Africans had never seen before
Answer:
conquer other nations and reduced people to slavery