Abstract
If the visual image and quantitative treatment of a form could be merged, the combination could become a powerful analytical method in morphology. A method is presented for creating an averaged outline. In this method, since the averaged outline is produced statistically, hypothesis testing can be performed on the visual image of the outlines. Intra‐ and intergroup variation of the outlines can then be assessed by taking allometry into account. This method is applied to the analysis of sexual differences in the midsagittal outline of recent (1880s–1920s) Japanese crania. The averaged outlines of both sexes showed subtle features that could not be detected by traditional measuring techniques. Because the roundness, flatness, or protrusion of specific aspects of the morphology are clearly apparent, sexual differences in this sample could be identified. Changes resulting from allometry did not seem to be present in either sex. The shape distance (DIR) introduced here matched well the visual impression derived from comparisons of the Japanese sample with a Jomon (Neolithic) male and the Broken Hill specimen.