Pearl lecture: Biological normalcy: A new framework for biocultural analysis of human population variation

Biological normalcy is a new analytical framework for understanding the bi-directional relationships between the biology of populations and cultural norms. Populations are characterized by statistical distributions-that is, measures of central tendency and variance-for biological traits, and these co-exist in societies with ideas about what constitutes "normal" human bodies, that is, normative views about what bodies "should" be like. While statistical norms may carry no explicit evaluative weight, the question is how they are related to judgments about what is "normal" or "abnormal." In a 1947 paper, Margaret Mead recognized their potential relationship: "normal…may refer to the statistically usual in the culture-usually without any recognition that this is culturally relative-so that the statistically usual is identified with the basically human…." Despite her observations over 70 years ago, little has been done on this topic, yet such work promises new insights into the relationship between culture and biology, here described at the population level, rather than as individual genetic characteristics. Using examples of sex/gender, race/ethnicity, age, and my work on human variation in the ability to drink milk, I outline the ways in which statistical norms may: influence individuals' perceptions of what is "normal" (Mead's "basically human"); lead to normative judgments about what human biology "should" be ("ethno-biocentrism") that are reinforced by biases in discourse about human variation; and potentially feedback to mold the biological characteristics of a population.