Andrew Gelman

"I think I’m starting to resolve a puzzle that’s been bugging me for awhile. Pop economists (or, at least, pop micro-economists) are often making one of two arguments:1. People are rational and respond to incentives. Behavior that looks irrational is actually completely rational once you think like an economist. 2. People are irrational and they need economists, with their open minds, to show them how to be rational and efficient. Argument 1 is associated with “why do they do that?” sorts of puzzles. Why do they charge so much for candy at the movie theater, why are airline ticket prices such a mess, why are people drug addicts, etc. The usual answer is that there’s some rational reason for what seems like silly or self-destructive behavior. Argument 2 is associated with “we can do better” claims such as why we should fire 80% of public-schools teachers or Moneyball-style stories about how some clever entrepreneur has made a zillion dollars by exploiting some inefficiency in the market. The trick is knowing whether you’re gonna get 1 or 2 above. They’re complete opposites!"

"I’m not saying that arguments based on rationality are necessarily wrong in particular cases. (I can’t very well say that, given that I wrote an article on why it can be rational to vote.) I’m just trying to understand how pop-economics can so rapidly swing back and forth between opposing positions. And I think it’s coming from the comforting presence of rationality and efficiency in both formulations. It’s ok to distinguish economists from ordinary people (economists are rational and think the unthinkable, ordinary people don’t) and it’s also ok to distinguish economists from other social scientists (economists think ordinary people are rational, other social scientists believe in “culture”). You just have to be careful not to make both arguments in the same paragraph."