In 1996, elderly Japanese people were asked: "How many years do you expect to live?" Their answers were recorded, and then everyone waited. Twenty-eight years later, the scientists compared those forecasts with the actual dates of death. It turned out that most people lived longer than they themselves had assumed. Women and those with a good education were especially likely to underestimate.
People without a university education more often named round numbers: 75, 80, 85. They also more often answered "I don't know." Such answers turned out to be less accurate. The most popular answer, 80 years, almost matched the average life expectancy in Japan that year. So people were unconsciously going by the statistics rather than by their own health and habits.
This knowledge can help with retirement planning. If a person underestimates how long they will live, they risk running out of money in old age. Pension advisers can identify such people and give them more accurate benchmarks.
Nearly 40% of respondents named a "round" age, a multiple of 5 or 10 years, and the most popular answer was 80 years, exactly how long Japanese people lived on average in 1996. Without knowing it, people were using birth statistics as an anchor for their own fate.
Not published on arXiv. Here are its page, the PDF and the formalization: you can check it yourself, not only read our account.