The theory of marginality in social economics, first coined in 1928 by Robert Park in his work "Human Migration and the Marginal Man," attempts to explain inconsistencies in the perceived value of individuals via reference to their social class or ethnicity, race or culture. Cultural marginality, for example, refers to the dilemmas of cross-cultural contact and assimilation.
In standard economics, marginalism is a theory that attempts to explain the discrepancy in the value of goods by reference to their secondary utility. According to this theory, diamonds are more expensive than water because even though water holds more total utility, the satisfaction of the diamonds — that is, their marginal utility — is enough to inflate the price past that of water.
As transport technology and readiness increases globally, the theory of marginality holds more and more relevance, since people of varied ethnicity, gender, nationality and culture commonly reside in the same locations. This theory is criticized by some for being too open to interpretation and too varied or complicated by nature. The more traditional work on marginality stresses the structural marginality of disenfranchised groups within societies, postulating that lack of access to the mainstream reward system can result in famine and powerlessness.