The question of what holds together a union of states, or what forces it apart, is in the spotlight. The union of European member states and the union of states that constitutes the UK are both under pressure. The relationship between the public and the institutions that represent these unions and between the publics within these unions is in flux. At the same time traditional public opinion measures used to gauge these relationships have been found wanting. Transformative methods are needed to address the shifting realities of the transforming union. Contributors to this panel adopt approaches using big data analysis, psychological experiments, face-emotion coding and fMRI brain scanning to gain new insights into attitudes and behaviours related to the union within the UK and between the UK and the EU.