Evolution of ethnocentrism
Experiments with bacteria and agent-based simulations of evolution are turning the study of evolution from an historical science into an experimental one. Some of the most intriguing simulations concern the evolution of ethnocentrism, the tendency to favor one’s own kind over other kinds. These simulations showed that from a neutral start, about 75% of a population evolves to be ethnocentric, cooperating (in Prisoner’s Dilemma games) only with agents sharing the same ethnic tag. Of other possible genotypic strategies, humanitarianism (cooperate with everyone) provides early competition, while selfishness (cooperate with no one) and traitorousness (cooperate only with out-groups) never establish much evolutionary momentum.
We showed that ethnocentrism dominates its early competitor humanitarianism by exploiting humanitarian agents along group frontiers once the world begins to fill up. Before that, it is even possible to see temporary stages of humanitarian dominance. The free-riding strategies of selfishness and traitorousness never really get rolling in evolutionary terms because these agents fail to take care of their own kind.
Because ethnocentrism in humans typically comes with a lot of negative baggage (discrimination, ethnic cleansing, war, etc.), it is important to understand how it originates and why it can be difficult to counter. Further research could usefully explore both evolutionary and environmental solutions. Just because a behavioral phenomenon has an evolutionary basis does not mean that it is ideal or impossible to change. There are examples of evolutionary tendencies being controlled or altered. Humans can find ways to cooperate across group lines.