A Polish social psychologist, sociologist, and publicist. His research focuses on conspiracy theories, prejudice, intergroup conflict, threats to positive social identity and dehumanization, mainly in the context of xenophobia, antisemitism, and ethnic conflicts. A University of Warsaw professor. Head of the Centre for Research on Prejudice at the University of Warsaw. Vice-chair of the Psychology Committee at the Polish Academy of Sciences. Member of the Scientific Council of the Robert B. Zajonc Institute for Social Studies.