Nudging in action has given us more insight into the way people make decisions. The key now is to use that knowledge to design more realistic policies.Five years ago, Richard Thaler and Cass Sunstein published Nudge: Improving Decisions about Health, Wealth and Happiness, a book that asked us to fundamentally change the way we think about how policy is made. Nudgechallenged the prevailing approaches to policy-making and governance that were grounded in the appealing idea that human beings are rational decision-makers, cognitively sophisticated enough to process all relevant information and unswayed by emotion. It presented several years’ worth of research to demonstrate that, by contrast, our decision-making is surprisingly malleable and therefore dramatically influenced by context. And if that is the case, Thaler and Sunstein asked, is it not possible to create the context that steers people toward the right choice (or at least the one we believe brings about the greatest common good)?