Quantitative hair form variation in seven populations.

Although hair form has received much attention in the past, it has rarely been studied systematically, and never using direct curling variables. In the present study, seven groups were scored on eight variables, including four newly-devised curling variables. These data were analyzed using univariate and multivariate techniques to give information about the population relations and mechanisms of hair form. “Racial” groups were separated using a principal components analysis. African and Melanesian populations were shown to have significantly different quantitative hair form traits, especially in regard to their regularity of curvature. The physiological, environmental, and genetic factors contributing to hair form variation are discussed. Cranial hair form has been one of the major racial criteria since the beginning of “anthropological thought,” but it is surprising how little systematic research has been done to delimit these population differences. For centuries such imprecise expressions as “frizzy” or “curly” have been in popular use. Such terms do not connote exact meanings to their users, and their vagueness has increased with continued use. Typologies using these terms have had an influence on current anthropological thought, not due so much to their perpetuation as to the failure of any adequate substitute to appear. There have been many classifications of hair form ranging from the classic formulation o f Huxley (Leiotrichi, Ulotrichi) (1865), to Deniker (Straight, Wavy, Frizzy, Woolly) (‘00), to Martin (Glatthaar, Wellighaar, Kraushaar) (’28), to Hooton (Straight, Wavy, Kinky, Woolly) (’46), to Garn (Straight, Wavy, Helical) (‘48). As Trotter, one of the great quantifiers of hair said (‘38), “There has been a slow and gradual change in the point of view of anthropologists . . . The tendency has been away from the two or three large groupings and toward smaller and more clearly defined categories.” The next obvious step is the quantification of hair form. Metric studies of hair have been done since the beginning of the century, but AM. J. P H Y S . ANTHROP., 39 7-18. with little emphasis on population differences. Hausman (‘25) and Wynkoop (‘29), for instance, were anthropologists interested in microscopic description and structural relations of hair. Later studies, such as those of Steggerda and Seibert (’41) and Trotter et al. (’56) have been more quantitative, but have generally been restricted by the lack of curling variables and the limitations of univariate statistics. The selection of variables is an important problem in the description of hair form. The variables must as accurately and completely as possible describe the hair. The most popular traditional hair form variables have been diameter of the hair shaft, cuticular scale count along the hair shaft, and cross-sectional index of the hair shaft. Cross-sectional index was usually measured by preparing thin, transverse sections of the hair shaft. However, spurious data can result from oblique sectioning, a technical difficulty which is increased in highly curled hairs. Cross-section had a great vogue in connection with Pruner-Bey’s (1864) theory associating cross-sectional index with curling. As Garn (’48) and others have pointed out, there is no consistent functional correlation between the two. The variables are associated in that a population with curly hair is likely to have elliptical crosssections, but this does not hold within the