just a snippet I found about the life expectancy stuff
Measuring quality of life is always a tricky thing, but the United Nations’ “Human Development Index” looks at three criteria: longevity, knowledge, and standard of living. In the case of the HDI, all three are measured in ways biased towards civilization. For example, longevity is measured by life expectancy at birth–a measure which presumes the common civilized assumption that life begins at birth. It does not weight the average with abortions, for example, even though there is disagreement even within our own culture of when life begins. Given such disagreement, we should not be terribly surprised to learn that other cultures have different measures of when life begins. Foraging cultures, for example, often believe that life begins at age two, and thus classify infanticide and abortion in the same category. Children are often not named or considered persons until that time. A !Kung woman goes into labor, and walks into the bush–maybe she comes back with a baby, and maybe she doesn’t. Whether stillborn or killed at birth, it’s not considered any business of anyone else’s. This kind of attitude has given foragers a very high infant mortality rate, leading many naive commentators to assume that their way of life must be terribly afflicted with disease to claim so many infants, and ultimately taking the skewed statistics that arise from such a practice to make statements on forager quality of life. In fact, all such commentary provides is a glimpse of the power of ethnocentrism to skew even what we might consider unbiased statistics.
A less biased measurement might take expected age of death at a given age. Richard Lee noted that up to 60% of the !Kung he encountered were over 60 (in Western countries, that number is 10-15%). The table provided by Hillard Kaplan, et. al, in “A Theory of Human Life History Evolution: Diet, Intelligence, and Longevity” (Evolutionary Anthropology, 2000, p. 156-185: PDF) is quite instructive. Comparing the Ache, Hazda, Hiwi and !Kung shows an average probability of survival to age 15 of 60% (reflecting the enormous impact of normative infanticide), but the expected age of death at age 15 shoots up to 54.1. In Burton-Jones, et. al, “Antiquity of Postreproductive Life: Are There Modern Impacts on Hunter-Gatherer Postreproductive Life Spans?” (American Journal of Human Biology, 2002, p. 184–205: PDF) another table is presented on p. 185, showing that at age 45, women of the !Kung could expect to live another 20.0 years for a total of 65 years, women of the Hadza could expect to live another 21.3 years for a total of 66.3 years, and women of the Ache could expect to live another 22.1 years for a total of 67.1 years. We should also bear in mind that all of the forager cultures examined to derive these statistics live in the Kalahari Desert–an extremely marginal and difficult ecosystem, even for foragers. Could we expect significantly higher numbers from foragers, if they were allowed to roam the sub-Saharan savannas to which humans are adapted, or verdant forests? We can only speculate, though the inuitive assumption would be affirmative.
An expected age of death even at 54.1, or even 67.1, may seem dismal to us in the United States, but even here in 1901, life expectancy was 49. It has only been very recently that civilized life expectancy has caught up to even the most marginal foragers. Moreover, in thesis #8, we explored the relationship between the First World and the Third World. Focusing on First World statistics produces the same skewed result as focusing only on medieval royalty, to the exclusion of the peasants they relied upon for their abundance. The worldwide average life expectancy, then, is the far more relevant measure than the United States’. That number is currently 67 years–exactly the number Burton-Jones found for !Kung women eking out a living in the Kalahari. Given the marginality of the ecosystems these foragers exist in, it seems that we could easily conclude from these data that the incredible advances made in our life expectancy–advances which are now slowing, due to the diminishing marginal returns of medical research (a point addressed explicitly in thesis #15)–we have managed to raise our life expectancy to that of the most meager and marginalized foragers.