Prejudice and Evolutionary Game Theory

by Malcolm Murray


Let us define prejudice as a propensity to treat members of a particular outgroup as having less moral worth than members of one's own group. Racism and sexism are kinds of prejudice, but so, too, is homophobia, as well as some fervent nationalisms.1 Prejudice is viewed as a problem for evolutionary ethics: prejudice clearly exists in our world, yet we also deem prejudice immoral.2 How can an evolutionary account explain the fit of a trait x at the same time as explaining the fit of a trait that tries to expunge x? If moral traits are those with fit (as evolutionary ethicists like to imagine), why would we not say prejudice is moral, as opposed to immoral? If both prejudice and moral indignation against prejudice can be explained on evolutionary models, what use are evolutionary models? This problem is a specific application of the general descriptive-normative problem. As even one of the evolutionary game theory pioneers, Maynard Smith, observes, "A scientific theory—Darwinism or any other—has nothing to say about the value of a human being."3 Assuming Smith is not doubting that humans have value, I believe that he is wrong here. The value of human beings is not something that we discover. Rather, we find that ascribing value to human beings confers advantage to the ascribers, and that advantage can be tracked through evolutionary models.