| Abstract: |
Update to the Osteological Paradox. Not in favor of Wood et al (1992) Illness did increase through time and life expectancy did decline with farming. Optimal foraging data suggest that the technological "improvements" in hunting and gathering preceding the adoption of agriculture, as well as the adoption of cereal farming itself, actually represent economic activities that are \iless\i efficient in energetic terms than the activities they replaced or supplement.: that is, they represent diminishing returns for labor compared, for examples, to the taking of large game. pg 244 \uWorldwide trends in relative health of prehistoric hunter-gatherers and farmers\u 1. frequency of dental caries commonly increased with agriculture 2. frequency of nonspecific, chronic infection displayed by skeletons was almost always higher among farmers than among earlier hunter-gatherers 3. frequency of specific infections such as yaws and TB or TB-like infections also increased as groups became larger and more sedentary 4. frequency of intestinal infections and parasites also increased with group size and sedentism when mummies or feces are studied 5. frequency of porotic hyperostosis was almost always higher among farmers than among earlier hunter-gatherers 6. other signs of malnutrition (retarded growth, osteoporosis, reduced tooth size, etc.) were more common among farmers than earlier hunter-gathers 7. The average stature of measured adult individuals declined throughout the Old World from the Paleolithic through the Neolithic periods. (New World samples over much shorter time spans showed more variable patterns). 8. signs of systemic stress visible in teeth including macroscopic enamel hypoplasia and microscopic Wilson bands were almost more frequent and pronounced in farmers than among earlier hunter-gatherers 9. the average ages of adults at death were often (but not always) lower among farmers than among foragers 10. indicators of workload (arthritis and robusticity of muscle attachments) showed mixed patterns with no clear trend. pg 245 Cohen believes that during the Neolithic Revolution there is a decline in dietary \iavailability\i of nutrients (i.e., some combination of reduced dietary intake and/or parasite-related losses of nutrients) associated with sedentism, increasing population density, and large population aggregates. sedentary farming was a decision bred of necessity, not choice or opportunity. Harpending (1990) argued that better-nourished farmers normally lived longer than their hunting and gathering coutnerparts and thus were more able to record stresses in their skeletons just as !Kung children who have become sedentary often appear less healthy than their counterparts but actually are more likely to survive. pg 249 It is known that anemia does increase with sedentism and increased population density as a function of howorm and other blood-destroying diseases that are density and sendentism dependent (or the body's own protective reation to infection) where or not cereal-based farming diets low in available iron are also implicated as once thought. There is good reason to argue on the basis of enthnographic exmaples and optimal foraging studies that hunter-gatherers would typically have had better background nutrition and fewer background infections (major components of resilience in response to new stresses) than do farmers and should be normally have been the more resilient (even though the stresses of mobility itself would clearly work against them.) !Kung foragers are hardly representative of prehistoric foraging economies. They are quite impoverished (for calories) by the standards of ther contemporary hunter-gatherers because the Kalahari is poor in resources, because civilized outposts (the cattle ranches themselves) have taken over most of the best resource areas, and because modern laws and the heat and aridity of the Kalahari limit their foraging ability. The Hadza are a better example. pg 251 \uArguments concerning scale of the data\u Local, random, or stochastic variables (such as irregular local population growth or decline) are theoretically possible, but they cannot be sufficient explanations for the broad pattern. For example, Sattenspiel and Harpending (1983) and Wood et al (1992) suggest that declining average age-at-death after the adaption of farming only demonstrates increased fertility/growth, not diminished real life expectancy. [This is accepted.] BUT, increasing fertility and growth only exert a visible effect on the age-at-death profile of the cemetery when the changes are relatively large - 5 to 10 times larger than Hassan's (or any plausible) estimate of the post-Neolithic acceleration of growth rate. In order for life expectancy to decline, fertility must have increased AND mortality must have decreased. Wood et al. make the point that frequency of pathology in a cemetery is not an accurate reflection of the frequency of illness in the population. But it does mean that when the paleopathology of two populations is being compared, the two cemetery samples should tend, on average, despite selective mortality, to be at least roughly proportional to thier parent populations, and the crude comparison should be valid even if the specific percentages are not. Moreover, although individual cemetery samples may be underepresentive as a result of markedly atypical selection or random factors, and some comparisons may be misleading because selection changes dramatically, there should be strong central tendency for skeletons, at least relatively, to reflect the once-living population from which they are derived. This central tendency should assert itself when many compartive samples are evaluated. In contrast to some other scholars, Cohen has argued that this trend reflects declining nutrition because it occurs in combination with the evidence from optimal foraging research, which suggests declining efficiency of food extraction during the same period. Wood et al. counter this with the statement that there may have been selection against smaller individuals during the growth period. Only the largest individuals would survive when selection is severe. For Wood et al.'s statement to be true then we would have to assume that most of the deaths or at least a significant amount of them would be against small people. We must also assume that changing sleection takes place against a background of therwise constant stature (within a single population). But it does not hold if we are comparing two \idifferent\i populations (or the same but different time periods) whose living and growing statures were different as a function of genetics, nutrition, or other factors. pg 256 life expectancy is not sufficient measure of population success, we must also focus on the changing \idistribution\i of deaths in the life span since an unchanging life expectancy could mask a shift in mortality from one age group to another. This theory could explain the paradox involving dental caries and arthritis. It is possible that with no real change in either cariogenesis or workload caries might increase in frequency and arthritis simultaneously decrease because changes in the survivorship during the ages at whihch each pathology commonly forms- caries in later childhood, arthritis in older adults ages.
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