Moral awareness polarizes people's fairness judgments.

How does moral awareness affect people's fairness judgments? Using a simple model of identity utility, I predict that if individuals differ in their personal fairness ideals (equality versus efficiency), reflecting over what one thinks is right should not only make people's choices less selfish but also more polarized. On the other hand, people's desire for conforming with the behavior of their peers could help mitigate polarization. I test these conjectures in a laboratory experiment, in which participants can pursue different fairness ideals. I exogenously vary (i) whether participants are prompted to state their moral opinions behind the veil of ignorance, and (ii) whether they are informed about the behavior of their peers. I find that moral introspection makes choices more polarized, reflecting even more divergent moral opinions. The increase in polarization coincides largely with a widening of revealed gender differences as introspection makes men's choices more efficiency-oriented and women's more egalitarian. Disclosing the descriptive norm of the situation is not capable of mitigating the polarization.