Claudia Hammond explores the psychology of regret with an audience at the Cheltenham Science Festival. What role do rueful thoughts on "what might have been" play in our lives? Is regret a wasted emotion or does it have some hidden benefits?

Joining Claudia on stage : Teresa McCormack - Professor of Cognitive Development at the School of Psychology, Queen's University Belfast who researches how regret in childhood can shape our decisions; novelist and essayist Sophie White - whose latest novel The Snag List examines the opportunity to go back in life and follow the road not taken; Fuschia Sirois - Professor of social and health psychology at Durham University whose research examines the impact of those "what if" thoughts on our health and wellbeing.

Producer Adrian Washbourne