The remedy is rarely exhortation. It is a change to the situation so that the easier choice is also the better one. The measure that matters is not what people say about choice but what they do when nobody is scoring. The usual story is that we are careless calculators. The better story is that we are careful about the wrong things. Ask most people why they did what they did and they will give you a reason; ask them again a week later and the reason will have quietly changed.
Why it persists
Consider the school run. It is a small thing, and small things are where habits live. The usual story is that we are careless calculators. The better story is that we are careful about the wrong things. The textbook treats choice as a preference to be revealed. In practice it is a story we tell ourselves after the fact. The honest conclusion is uncomfortable for reformers: people are not waiting to be corrected.
