 Processes that result in the emergence of such identification are called ethnogenesis.Members of an ethnic group, on the whole, claim cultural continuities over time, although historians and cultural anthropologists have documented that many of the values, practices, and norms that imply continuity with the past are of relatively recent invention.Ethnic groups differ from other social groups, such as subcultures, interest groups or social classes, because they emerge and change over historical periods (centuries) in a process known as ethnogenesis, a period of several generations of endogamy resulting in common ancestry (which is then sometimes cast in terms of a mythological narrative of a founding figure); ethnic identity is reinforced by reference to "boundary markers" - characteristics said to be unique to the group which set it apart from other groups.