Prof. Louis presents a program of research that considers peace and conflict as group norms, i.e., social rules or standards for behaviour. Polarising group processes clearly affect collective decision-making, for topics from security to environmental sustainability to human rights. Further, the lessons learned from a group-based approach to conflict escalation do not always align with those put forward in contemporary models of social cohesion, conflict resolution or deradicalisation that focus at the individual and societal levels. She argues that overlooking group processes is contributing to failed interventions in conflict and observed backlash effects.