Professor Richard Thaler has spent his career investigating how people really behave – how we save for retirement, what we choose to eat, how we use energy. Through understanding the many reasons for human misjudgement, such as being too optimistic, or facing too many choices, Richard Thaler's work has helped people make better decisions. The concept is known as "nudge" and nudge units are now commonplace in governments and businesses around the world to develop better policy. Guest: Professor Richard Thaler, Professor of Behavioural Science and Economics, University of Chicago Booth School of Business, 2017 recipient of the Nobel Memorial Prize in Economic Sciences and co-author of "Nudge".