METHODS OF DETERMINING AGE AND SEX

Methods of Determining Age and Sex

Methods of Determining Age and Sex

Introduction

Comparison of different adult age estimation methods on the same skeletal sample with unknown ages could forward paleodemographic inference, while researchers sort out various controversies. The original aging method for the auricular surface (Lovejoy et al., 1985a) assigned an age estimation based on several separate characteristics. Researchers have found this original method hard to apply. It is usually forgotten that before assigning an age, there was a seriation, an ordering of all available individuals from youngest to oldest. Thus, age estimation reflected the place of an individual within its sample. A recent article (Buckberry and Chamberlain, 2002) proposed a revised method that scores theses various characteristics into age stages, which can then be used with a Bayesian method to estimate an adult age distribution for the sample. Both methods were applied to the adult auricular surfaces of a Pre-Columbian Maya skeletal population from Copan, Honduras and resulted in age distributions with significant numbers of older adults. However, contrary to the usual paleodemographic distribution, one Bayesian estimation based on uniform prior probabilities yielded a population with 57% of the ages at death over 65, while another based on a high mortality life table still had 12% of the individuals aged over 75 years. The seriation method yielded an age distribution more similar to that known from pre-industrial historical situations, without excessive longevity of adults. Paleodemography must still wrestle with its elusive goal of accurate adult age estimation from skeletons, a necessary base for demographic study of past populations. Am J Phys Anthropol 132:40-47, 2007.

Methods of Determining Age and Sex

Paleodemography based on skeletons has been a contentious and ever-evolving undertaking for the last 40 years (Petersen, 1975; Hoppa, 2002), but recent controversy has questioned how to determine, with some accuracy, an age distribution of deaths. This remains one of the useful pieces of demographic information available about past populations. However, skeletal age distributions differ from the age distribution of deaths of recent and historical populations. Skeletons can be aged fairly accurately, with well-defined estimates of error, as juveniles and young adults younger than 30 years (Cox, 2001). However, current methods for estimating the age of older adults are considered to lack both precision and accuracy (Cox, 2001). The ultimate question for paleodemography is whether traditional skeletal aging techniques have revealed a real pattern for past populations, or are they just responsible for what are actually deviant patterns of ages at death? Questions do arise, because skeletal samples often have estimated age distributions of deaths that are different from those of model life tables often used by researchers as emblematic of the human pattern. Skeletal samples seem to have higher proportions of prime age adults and low proportion of individuals over 50 years of age at death (Storey, 1992; Paine, 1997). Model life table patterns are based on recent historical populations with unprecedented longevity, while skeletally derived patterns have very low overall survivorship with high adult mortality levels compared ...