Ronald Lee

According to a new hypothesis by Harvard alumnus Ronald Lee, the answer lies in interpreting the process of natural selection. Lee, professor of demography and economics at the University of California, Berkeley, spoke on November 14 at William James Hall, Cambridge, as part of the Lectures on Population at Harvard series. Lee’s talk was co-sponsored by the Office of the Provost, HSPH Office of the Dean, and the Harvard Center for Population and Development Studies.

Lee proposed that natural selection favors adults capable of providing necessary goods and services that help take care of young children. These provisions and their related "transfer of calories" are as important as fertility, he said. In this framework, individuals who are unwilling, unable or unlikely to have children continue to play a crucial role in the survival of the human species. For example, grandparents who help care for their grandchildren keep the kids safe and healthy while providing support to their reproducing female relatives who can then bear more children at closer intervals.

Lee has studied several existing hunter-gatherer societies, noting the food calories acquired and consumed at each age. Children at young ages do not contribute goods to society and do not start producing what they consume until an average age of 20. Lee found it cost society 10 times more calories to raise a single surviving child to age 20 than to maintain an adult. So, adults must make up the difference, producing more than they consume, resulting in an important role even for those individuals who do not reproduce directly.

The hypothesis is described in "Rethinking the Evolutionary Theory of Aging: Transfers, Not Births, Shape Senescence in Social Species," which appeared in the August 5 issue of the Proceedings of the National Academy of Sciences.

For more information about the Lectures on Population at Harvard series, visit http://www.hsph.harvard.edu/poplectures/.

Lecture Tentatively Rescheduled

Due to weather conditions, the lecture on December 8 by Burton H. Singer, Charles and Marie Robertson Professor of Public and International Affairs, Woodrow Wilson School, Princeton University, was postponed. The talk has been tentatively rescheduled for February 25.

Singer will speak on "Urbanization, Malaria, and Development." Location and time will be announced at a later date. For more information, visit the web site at http://www.hsph.harvard.edu/poplectures/.