Anthropology professors Rachel Caspari and Sang-Hee Lee, of Central Michigan University and the University of California at Riverside, respectively, chose instead to analyze the relative ages of skeletons found in archeological digs in eastern and southern Africa, Europe, and elsewhere.

After comparing the proportion of those who died young with those who died at an older age, the team concluded that longevity only began to significantly increase—that is, past the age of 30 or so—about 30,000 years ago, which is quite late in the span of human evolution.