In this *Times* article, Bob Willis discusses a study of memory among retirement-age adults in U.S. and Europe, made possible by the collection of datasets in other countries comparable to the Health and Retirement Study. Willis and his colleagues found a straight-line relationship between the percentage of people in a country who are working at age 60 to 64 and their performance on memory tests. The longer people in a country keep working, the better, as a group, they do on the tests when they are in their early 60s.

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