Some scholars have built on Polanyi's four original modes of exchange, others have developed entirely new schema (Smith 1976). Earle (1977: 213-216) argues that Polanyi's (1957: 250) definition of redistribution as "appropriational movements towards a center and out of it again..." is vague and Earle observes that this definition is so broad that it could to apply to economic systems ranging from central storage of goods in Babylonia to meat distribution in band-level hunters. Earle advocates separating leveling mechanisms from institutional mechanisms, where institutionalized redistribution involves wealth accumulation and political transmission between elites across broad regions in the mode of peer-polity interaction (Earle 1997).