Advances in cognitive and behavioral science show that the way options are presented—commonly referred to as “choice architecture”—strongly influences our decisions: we tend to react to a particular option differently depending on how it is presented. Studies suggest that we often make irrational choices due to the interplay between choice architecture and systematic errors in our reasoning—cognitive biases. Based on this data, Richard Thaler and Cass Sunstein came up with the idea of a "nudge," which they define as a small change in the choice architecture that steers people towards certain choices without limiting their options. Central to the debate on nudging is the question of when, or under what circumstances, it is ethical to nudge s...