As fundamentally social beings, we usually keep company with the people that think like ourselves: Our friends and loved ones. This project aims to deliver a unifying theory of human sociality that can account for why the human brain may want to avoid conflict between own and others' ways of thinking. This will be achieved via online behavioural experiments, a highly innovative functional magnetic resonance imaging (fMRI) design, and philosophical approaches. The project expects to generate knowledge on the social neuroscience of political/religious group behaviour, shedding light on the brain mechanisms that underlie social cognition. It will benefit our approach to societal problems like discrimination, fundamentalism and extremism.