Collective guilt serves intergroup relations better than collective shame does.

Evidence

We suggested earlier that some of the responses evoked by both emotions might have a dampening effect on intergroup conflict. Nonetheless, we think that the evocation of guilt may generally have more positive effects than the evocation of shame. In the research on interpersonal relationships, guilt is considered much more adaptive for relationships than shame (Tangney, 1995.) A reexamination of the responses promoted by shame and guilt sheds some light on why guilt may be a more productive emotional response in intergroup settings as well. — Nyla R. Branscombe and Bertjan Doosje (eds.), Collective Guilt, 368