His research focuses on processes of social identification and intergroup relations, primarily in the context of large social categories such as nations and ethnic groups. Specifically, his research is at the crossroad of the social psychological areas of norms and morality (e.g., moral disengagement in response to in-group wrong-doings), intergroup threat (e.g., threat-induced shifting of moral principles such as fairness or loyalty), and social justice (e.g., reparations after in-group wrong-doings; and conflict resolution).