Understanding people turns out to be a more urgent task than changing them, and a great deal harder. It is tempting to call this irrational. It is more useful to ask what it is for. The usual story is that we are careless calculators. The better story is that we are careful about the wrong things. If you want to see memory at work, watch a queue form where there is no reason for one.
The ordinary case
Economists have spent decades modelling memory as a quantity. It behaves more like a weather system. A better account of memory would begin with the ordinary case rather than the laboratory one. There is a version of this essay that ends with a policy prescription. This is not that version; the mechanism is interesting enough on its own. The evidence here is thinner than the confident commentary suggests, and the honest position is a shrug with a direction of travel.
