—“Ethnocentrism beats humanitarianism because ethnocentrics do a better job at suppressing selfish free riders.
If an ethnocentric group comes across a group riddled with selfish individuals, they’ll refuse to cooperate. Over time, thanks to the ethnos’ mutual cooperation and the selfish group’s total refusal to even help themselves out, ethnos will reproduce faster than the non-cooperators and thus expand at the selfish group’s expense.
Meanwhile those nice humanitarian fellows blissfully waste their precious reproductive potential helping out free riders, who are all to happy to receive their favor, giving nothing in return. We call this idea, that ethnocentrism beats humanitarianism because it is better at suppressing free-riders, the “mediation hypothesis,” and it is the mechanism favored by Hammond and Axelrod in their original paper.
Another possibility is that ethnocentrism beats humanitarianism outright. Imagine an ethno group next to a humanitarian group. Individuals on the group boundary benefit from the cooperation of their own group-mates behind them. But the ethnocentrics at the front doubly benefit from the cooperation of those hapless humanitarians. Might this give the ethnos the edge they need? We call this the “direct hypothesis”.—-