The usual story is that we are careless calculators. The better story is that we are careful about the wrong things. The evidence here is thinner than the confident commentary suggests, and the honest position is a shrug with a direction of travel. If you want to see pride at work, watch a queue form where there is no reason for one. In the studies we have, the effect is modest, reliable and almost entirely ignored by the people it describes.
Where it overreaches
We describe the departure from the model as an error. We might equally describe the model as a hopeful guess about us. The lesson is modest. Build for the person who exists, not the one in the model. The point is not that people are foolish. The point is that pride is expensive, and we economise on it like everything else. The mind that evolved for small groups and immediate dangers is now asked to manage a pension. It does its best.
