How malleable are the attitudes of people in a post-conflict society toward their former adversaries? I conduct a laboratory experiment in Azerbaijan, which fought a war against its neighbor Armenia in the 1990s, to investigate whether reconsideration of the roots of the conflict can influence interethnic attitudes. Subjects are assigned differing interpretations of the conflict and asked to think about or discuss their reactions. The results indicate that the most effective interventions work through, rather than against, existing beliefs. Discussion also plays a critical role in provoking the introspection that is necessary to challenge longstanding prejudices. The analysis provides insight into the social psychological processes of prejudice reduction and offers caveats to conventional policy interventions to encourage reconciliation.