Resource Availability, Mortality and Fertility: A Path Analytic Approach to Global Life History Variation

Humans exhibit considerable diversity in timing and rate of reproduction. Life history theory suggests that ecological cues of resource richness and survival probabilities shape human phenotypes across populations. Populations experiencing high extrinsic mortality due to uncertainty in resources should exhibit faster life histories. Here we use a path analytic approach informed by life history theory to model the multiple pathways between resources, mortality rates, and reproductive behavior in 191 countries. Resources that account for the most variance in population mortality rates are predicted to explain the most variance in total fertility rates. Results indicate that resources (e.g., calories, sanitation, education, and health care expenditures) influence fertility rates in paths through communicable and non-communicable diseases. Paths acting through communicable disease are more strongly associated with fertility than are paths through non-communicable diseases. These results suggest that a path analytic approach may help disaggregate extrinsic and intrinsic mortality factors in cross-cultural analyses. Such knowledge may be useful in developing targeted policies to decrease teenage pregnancy and total fertility rates and so issues associated with overpopulation