MAOA and Aggression: A Gene–Environment Interaction in Two Populations

Political scientists tend to focus on environmental triggers as the primary precipitating cause for political violence. However, little has been done to explain why certain individuals faced with certain pressures resort to violence, while others confronting the same situation seek out diplomatic and peaceful resolutions to conflict. Here, using two independent samples, we explore the interaction between genetic disposition and violent early life events and their influence on engaging in physical violence. We find that individuals with the low-activity form of monoamine oxidase-A, who are exposed to violence in youth have a greater likelihood of engaging in physical aggression later in adulthood. Our findings hold important implications for the value of environmental intervention in communities besieged by political violence in order to reduce the likelihood of the intergenerational transfer of its propensity.