There is a fashionable new science, behavioral economics, which applies the insights of psychology to how people make economic decisions. It tries to explain, for instance, the herd instinct that led people during the recent bubble to override common sense and believe things about asset values because others did. the " bandwagon effect." Behavioral economics has also brought us notions like "loss aversion", how we hate giving up a dollar we have far more than forgoing a dollar we have not yet got.But while there is a lot of interest in the psychology and neuroscience of markets, there is much less in the psychology and neuroscience of government. Slavisa Tasic, of the University of Kiev, wrote a paper recently for the Istituto Bruno Leoni in Italy about this omission. He argues that market participants are not the only ones who make mistakes, yet he notes drily that "in the mainstream economic literature there is a near complete absence of concern that regulatory design might suffer from lack of competence." Public servants are human, too.Mr. Tasic identifies five mistakes that government regulators often make: action bias, motivated reasoning, the focusing illusion, the affect heuristic and illusions of competence. In the last case, psychologists have shown that we systematically overestimate how much we understand about the causes and mechanisms of things we half understand. The Swedish health economist Hans Rosling once gave students a list of five pairs of countries and asked which nation in each pair had the higher infant-mortality rate. The students got 1.8 right out of 5. Mr. Rosling noted that if he gave the test to chimpanzees they would get 2.5 right. So his students" problem was not ignorance, but that they knew with confidence things that were false.The issue of action bias is better known in England as the "dangerous dogs act," after a previous government, confronted with a couple of cases in which dogs injured or killed people, felt the need to bring in a major piece of clumsy and bureaucratic legislation that worked poorly. Undoubtedly the hasty legislation following the current financial crisis will include some equivalents of dangerous dogs acts. It takes unusual courage for a regulator to stand up and say "something must not be done," lest "something" makes the problem worse.Motivated reasoning means that we tend to believe what it is convenient for us to believe. The focusing illusion partly stems from the fact that people tend to see the benefits of a policy but not the hidden costs. "Affect heuristic" is a fancy name for a pretty obvious concept, namely that we discount the drawbacks of things we are emotionally in favor of. If lawmakers are to understand how laws get applied in the real world, they need to know and understand the habits of mind of their officials. The "bandwagon effect" is one in which people ______

A. follow a popular trend blindly
B. turn attention to asset values
C. develop a strong dislike for losses
D. believe the insights of psychologists