The Evolution of Ethnocentrism

Ross Hammond, a Ph.D. candidate in Political Science at the University of Michigan, leads CSED scholars and affliates in a discussion of his collaborative work on the role of ethnocentrism in influencing cooperation.

Ethnocentrism is a nearly universal syndrome of discriminatory attitudes and behaviors.
Ethnocentric behaviors are typically based on observable characteristics regarded as indicating common descent, and are often territorially based. Hammond and Axelrod show that these two characteristics alone can be sufficient for the evolution of widespread ethnocentric behavior. They also show that ethnocentrism can support contingent cooperation in the form of in-group favoritism without requiring mechanisms such as reciprocity, reputation, conformity, or leadership.

Using a simple evolutionary model of
local competition between individuals, the authors draw on the literature on “tags” to model observable indicators of common descent and the literature on localism to model territoriality. Hammond and Axelrod show that ethnocentric behavior emerges and is sustained in the model under a wide range of conditions, even against free-riding egoists. Surprisingly, widespread ethnocentrism can support very high aggregate levels of cooperation. When cooperating is especially costly to individuals, we show how
ethnocentrism itself can be necessary to sustain cooperation.