LONDON, Ontario—Research showing the importance of genetic similarity to group loyalty and patriotism was published in the October issue of Nations and Nationalism, an academic journal of the London School of Economics.
The paper, entitled “Ethnic nationalism, evolutionary psychology, and genetic similarity theory” shows that genetic similarity is a “social glue” in groups as small as two spouses and best friends, or in those as large as nations and alliances.
The evidence comes from studies of identical and non-identical twins, adopted and non-adopted children, blood tests, social assortment, heritabilities, family bereavements, and large-scale population genetics.
For example, identical twins grieve more for their co-twin than do non-identical twins. And, family members grieve more for children who resemble their side of the family than they do their spouse’s side.
Also, spouses who are more genetically similar have longer and more satisfying marriages.
Based on their DNA, two randomly chosen individuals from the same ethnic group are found to be as related as first cousins.
Thus, two random people of English ancestry are the equivalent of a 3/8 cousin compared to people from the Near East; a 1/2 cousin by comparison with people from India; and like full cousins by comparison with people from China.
The study’s author, J. Philippe Rushton, professor of psychology at the University of Western Ontario said, “This explains why people describe themselves as having “ties of blood” with members of their own ethnic group, who they view as “special” and different from outsiders; it explains why ethnic remarks are so easily taken as ‘fighting words.’”
Human social preferences, like mate choice and ethnic nepotism, are anchored in the evolutionary psychology of altruism. Adopting a “gene’s eye” point of view allows us to see that people’s favoritism to kin and similar others evolved to help replicate shared genes.
Since in aggregate people share more genes with their co-ethnics than they do with their relatives, ethnic nepotism is a proxy for family nepotism.
The paper describes the history of the Jewish people as providing perhaps the best-documented example of how genetic similarity intersects culture, history, and even politics.
Jewish groups are genetically similar to each other even though they have been separated for two millennia. Jews from Iraq and Libya share more genes with Jews from Germany and Russia than either group shares with the non-Jewish populations among whom they have lived over the intervening centuries.
Recent DNA studies of the ancient Hindu caste system has confirmed that upper castes are more genetically related to Europeans than are lower castes who are genetically more related to other south Asians. Although outlawed in 1960, the caste system continues to be the main feature of Indian society, with powerful political repercussions.
The paper described the group-identification processes as innate—part of the evolved machinery of the human mind. Even very young children make in-group/out-group distinctions about race and ethnicity in the absence of social learning.
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Author: J. Philippe Rushton, Department of Psychology, University of Western Ontario, London, Ontario, N6A 5C2, Canada. Email: [email protected]; Tel: 519-661-3685.
On the Web: Downloadable Article: http://www.ssc.uwo.ca/psychology/faculty/rushton
Full Citation: Rushton, J. P. (2005). Ethnic nepotism, evolutionary psychology, and genetic similarity theory. Nations and Nationalism, 11, 489-507.
Article Abstract: Genetic Similarity Theory extends Anthony D. Smith’s theory of ethno-symbolism by anchoring ethnic nepotism in the evolutionary psychology of altruism. Altruism toward kin and similar others evolved in order to help replicate shared genes. Since ethnic groups are repositories of shared genes, xenophobia is the ‘dark side’ of human altruism. A review of the literature demonstrates the pull of genetic similarity in dyads such as marriage partners and friendships, and even large groups, both national and international. The evidence that genes incline people to prefer others who are genetically similar to themselves comes from studies of social assortment, differential heritabilities, the comparison of identical and fraternal twins, blood tests, and family bereavements. DNA sequencing studies confirm some origin myths and disconfirm others; they also show that in comparison to the total genetic variance around the world, random co-ethnics are related to each other on the order of first cousins.