Tatu Vanhanen (2014)
The purpose of this article has been to explore why ethnic conflicts tend to break out in all ethnically divided societies. The principal explanation was traced to the evolved disposition for ethnic nepotism shared by all human populations. Ethnic nepotism was measured roughly by the degree of ethnic heterogeneity of the populations. It was correlated with the scale of ethnic conflicts in the group of 187 countries. The results of correlation analysis indicate that ethnic heterogeneity explains 55% of the variation in the scale of ethnic conflicts, and the results of regression analysis disclose that the same relationship more or less applies to all 187 countries. These results led to the conclusion that ethnic nepotism is the common cross-cultural background factor which supports the persistence of ethnic conflicts in the world as long as there are ethnically divided societies.