Behavioural economics is a branch of economic research that adds elements of psychology to traditional models in an attempt to better understand decision-making by investors, consumers and other economic participants. Behavioural economics challenges the assumption that agents always make rational choices with the aim of maximising utility. The leading behavioural economist, Richard Thaler, won the Nobel Prize in Economics in 2017 for his work on behavioural economics and policy interventions built around "nudges".