David Halpern leads the UK's Behavioural Insights Team, focusing on how behavioral science informs policy and social trust. Bob Putnam, a Harvard professor, dives into social capital and its evolution. They discuss the alarming decline of social trust in the U.S. and UK, linking it to increased diversity and social disengagement. The pair highlights how trust affects community wellbeing and economic growth, exploring pathways to rebuild social connections. Anecdotes and research underline the critical need for fostering trust in an increasingly complex society.