4. Anthropological and Evolutionary Demography

Demography was once a subfield of the social sciences dedicated to the statistical study of birth and death rates and the mathematical description of these vital rates (function fitting). This also included an empirical examination of proximate factors that affect vital rates. Anthropological demography focused mainly on small scale (non-Western) societies, and employed interpretations drawn from so-called “anthropological theory” (eg. Howell 1986; Campbell and Wood 1998; Kertzer and Fricke 1997; Bernardi 2007). Cross cultural comparisons were a mainstay of the field. In the past 30 years, however, anthropological demography changed significantly, to become a theoretically informed study of mortality and fertility, and other age-related biological features. The theory is based on an evolutionary perspective that can unite human demographic studies with those of other primates, mammals, and vertebrate species (eg. Hill 1993; Kaplan 1996; Vaupel 2010, Blurton Jones 2016). This transition expanded the field from the study of vital rates, to one including research on growth, development, aging patterns, etc., (physiological, cognitive, emotional mechanisms) that are strongly theoretically tied to mortality and fertility schedules (eg. Ketterson and Nolan 1992; Rickleffs and Wikelski 2002; Kaplan and Gangestad 2005; Kirkwood and Austad 2000). These important changes in the field emerged primarily from the injection of Life History Theory from biology into the social sciences. A fundamental proposition of evolutionary biology is the recognition that fertility and mortality are the two components of individual fitness. Hence all phenotypic adaptations that act on one or both of these components will evolve via natural selection. From this view it is clear that the mechanisms of fertility and survival are key biological adaptations and can only be fully understood in the context of evolution.