Causal pathways and causal processes: Studying the evolutionary prehistory of human diversity in language,customs, and biology

An issue of continuing interest to Pacific archaeologists—the “question of Polynesian origins”—is examined (1) to illustrate a set of basic concepts (pattern, pathway, and process) helpful when talking about the origins, maintenance, and stability of similarities and differences among human populations, and (2) to document, by case example, how one particular temporal pathway of development leading to one historically specific pattern of human variability may tell us something in general, as well as something in particular, about the evolutionary processes leading to human diversity in language, customs, and biology. Contrary to the conventional assumption that the first Polynesians migrated from a homeland located somewhere in Southeast Asia, a simple biological model based on perhaps no more than three types or kinds of event sequences—i.e., causal processes—suggests how modern Polynesian speakers may be derived from an ancestral population(s) once resident in the region of the Pacific we now speak of as Melanesia.