ethnic nepotism: its proponents don't just study it, they practice it

wikipedia | In sociology, the term ethnic nepotism describes a human tendency for in-group bias or in-group favouritism applied by nepotism for people with the same ethnicity within a multi-ethnic society.

The theory views ethnocentrism and racism as nepotism toward extended kin and an extension of kin selection. In other words, ethnic nepotism points toward a biological basis for the phenomenon of people preferring others of the same ethnicity or race; it explains the tendency of humans to favor members of their own racial group by postulating that all animals evolve toward being more altruistic toward kin in order to propagate more copies of their common genes.

"The myth of common descent", proposed by many social scientists as a prominent ethnic marker, is in his view often not a myth at all.[clarification needed] "Ethnicity is defined by common descent and maintained by endogamy".[2]

To guard one's genetic interests, Frank Salter notes altruism toward one's co-ethnics:

Hamilton's 1975 model of a genetic basis for tribal altruism shows that it is theoretically possible to defend ethnic genetic interests in an adaptive manner, even when the altruism entails self sacrifice. He argued mathematically that an act of altruism directed towards the tribe was adaptive if it protected the aggregate of distant relatives in the tribe. In sexually-reproducing species a population's genetic isolation leads to rising levels of interrelatedness of its members and thus makes greater altruism adaptive. Low levels of immigration between tribes allow growing relatedness of tribal members, which in turn permits selection of altruistic acts directed at tribal members, but only if these acts "actually aid in group fitness in some way...." Closely related individuals are less likely to free ride and more likely to invest in and thus strengthen the group as a whole, improving the fitness of its members.[3]

Regarding how this translates into politics and why homogeneous societies are more altruistic, Frank Salter writes:

Relatively homogeneous societies invest more in public goods, indicating a higher level of public altruism. For example, the degree of ethnic homogeneity correlates with the government's share of gross domestic product as well as the average wealth of citizens. Case studies of the United States, Africa and South-East Asia find that multi-ethnic societies are less charitable and less able to cooperate to develop public infrastructure. Moscow beggars receive more gifts from fellow ethnics than from other ethnics. A recent multi-city study of municipal spending on public goods in the United States found that ethnically or racially diverse cities spend a smaller portion of their budgets and less per capita on public services than do the more homogenous cities.