R. Lee Lyman and Michael J. O'Brien
Categorization of individual phenomena has several purposes: the categories provide an information storage and retrieval system; they simplify variation into a small, manageable number of kinds more easily discussed than each individual specimen; and they provide a means of recording variation for purposes of analysis. Given these purposes, categorization occurs in virtually all endeavors. A librarian must decide if a newly published book is a work of fiction, a work of history, or a work of historical fiction. Astronomers must decide if a newly discovered celestial body is a star, a planet, a moon, an asteroid, or something else entirely. Pedologists must decide which category of soil occurs in a particular area. When you buy a new car, you must decide if you want to drive a Ford, a Chevrolet, or a Toyota.
Anthropologists have used a host of sorting systems to simplify, organize, and analyze the materials they study. Nineteenth-century philologists categorized languages in a manner still used to assess the evolutionary development and relations of modern languages. Late in the nineteenth century, Americanist anthropologists applied the notion of culture areas to sort collections of artifacts for museum displays. Nineteenth-century anthropometrists sorted people in various ways, one of the better-known ones using the length-width ratio of the skull—the “cephalic index” developed by Anders Retzius in 1842. A person is brachycephalic (short, broad head) if his skull is 82% as wide as it is long, dolichocephalic (long, narrow head) if his skull is 77% as wide as it is long, and mesocephalic if the length- width ratio falls between those values. These categories were sometimes