Consider the school run. It is a small thing, and small things are where habits live. A better account of expertise would begin with the ordinary case rather than the laboratory one. It is tempting to call this irrational. It is more useful to ask what it is for. None of this is new. Adam Smith noticed most of it, and then the profession spent two centuries forgetting.
What it gets right
The mind that evolved for small groups and immediate dangers is now asked to manage a pension. It does its best. Institutions know all this, of course, which is why the school run is so rarely left to chance. Put a number on expertise and it becomes a target; put a target on it and the number stops meaning what it meant. The honest conclusion is uncomfortable for reformers: people are not waiting to be corrected.
