Possibly it isn't especially noticeable, but this weekend I've been working on the sidebar. In particular I've added a new category of 'scientific blogs' whole interests one way or another touch on those we have here. Among these John Hawks Anthropology Weblog. This morning I notice that John's most recent post is indeed of interest to us:
".....mortality rates are malleable. They are changed not only by improvements in health, nutrition, and environment across the lifespan; they are also improved by short-term changes in older adults."
John is, as you might imagine from the title of his blog, probably more interested in the Upper Paleolithic than he is in our contemporary issues, but the two epochs are not entirely unconnected in what we can learn from them about the evolution of our lifespan. John's post is also useful since it serves as an introduction to the work of James Vaupel and raises importanbt issues about the relations between genetics and culture in understanding our lifespan.
In so doing he directs us to two other researchers - Sang-Hee Lee and Rachel Caspari
- whose work centres on this topic. In a recent paper Caspari and Lee conclude that:
"the increase in adult survivorship associated with the Upper Paleolithic is not a biological attribute of modern humans, but reflects important cultural adaptations promoting the demographic and material representations of modernity".
Unfortunately this paper is not freely available online, but an earlier paper - Older age becomes common late in human evolution - (published by the US National Academy of Sciences) is:
"Increased longevity, expressed as number of individuals surviving to older adulthood, represents one of the ways the human life history pattern differs from other primates. We believe it is a critical demographic factor in the development of human culture. Here, we examine when changes in longevity occurred by assessing the ratio of older to younger adults in four hominid dental samples from successive time periods, and by determining the significance of differences in these ratios. Younger and older adult status is assessed by wear seriation of each sample. Whereas there is significant increased longevity between all groups, indicating a trend of increased adult survivorship over the course of human evolution, there is a dramatic increase in longevity in the modern humans of the Early Upper Paleolithic. We believe that this great increase contributed to population expansions and cultural innovations associated with modernity."
Incidentally you can find a good selection of Sang-Hee Lee's work here.