Supplementary material for Backwell and d’Errico (January 16, 2001) Proc. Natl. Acad. Sci. USA, 10.1073/pnas.021551598
Fig. 8.
Image analysis of the wear patterns on the Swartkrans fossils and on experimental bone tools. (A) Variability (Upper) and mean (Lower) in the orientation of the striations on the Swartkrans tools (S) and on experimental tools used to dig termites mounds (T), to excavate the ground in search of tubers and larvae (G), and to extract bulbs (B) [Brain's experimental tools (7)]. An unpaired t test has shown the orientation of the striations on the Swartkrans and termite digging tools to be the most similar, and significantly different from the other experimental tools. (B) Striation width as measured at ´40 magnification on all the striations visible. A nonparametric statistical test has shown the striation widths on all the experimental tools to be significantly different from each other, but with the closest similarity recorded between the Swartkrans and termite digging tools.