Adam Smith’s actors in The Theory of Moral Sentiments are driven by an internal struggle between their impulsive, fickle and indispensable passions, and their impartial spectator. They weigh out-of-pocket costs more than opportunity costs, have self-control problems and are overconfident. They display erratic patterns of sympathy, but are consistently concerned about fairness and justice. They are motivated more by ego than by any kind of direct pleasure from consumption, and, though they don’t anticipate it, ultimately derive little pleasure from either. In short, Adam Smith’s world is not inhabited by dispassionate rational purely self-interested agents, but rather by multidimensional and realistic human beings.

— Nava Ashraf, Colin F. Camerer and George Loewenstein, Adam Smith, Behavioral Economist