The remedy is rarely exhortation. It is a change to the situation so that the easier choice is also the better one. It is tempting to call this irrational. It is more useful to ask what it is for. The lesson is modest. Build for the person who exists, not the one in the model. The usual story is that we are careless calculators. The better story is that we are careful about the wrong things.
Where the model breaks
Put a number on envy and it becomes a target; put a target on it and the number stops meaning what it meant. The textbook treats envy as a preference to be revealed. In practice it is a story we tell ourselves after the fact. The usual story is that we are careless calculators. The better story is that we are careful about the wrong things. The honest conclusion is uncomfortable for reformers: people are not waiting to be corrected.
