Understanding people turns out to be a more urgent task than changing them, and a great deal harder. Institutions know all this, of course, which is why the free sample is so rarely left to chance. We describe the departure from the model as an error. We might equally describe the model as a hopeful guess about us. If you want to see nostalgia at work, watch a queue form where there is no reason for one.
Where the model breaks
The usual story is that we are careless calculators. The better story is that we are careful about the wrong things. Economists have spent decades modelling nostalgia as a quantity. It behaves more like a weather system. The remedy is rarely exhortation. It is a change to the situation so that the easier choice is also the better one. The strange thing about the free sample is not that it exists but that it works, most of the time, for most people.
