Quantifying Oldowan Stone Tool Production at Olduvai Gorge, Tanzania
Fig 5
Experimental vs. archaeological distribution of Oldowan stone tool manufacturing behaviors and associated classification error margins.
The first distribution (“Experimental Expectation”) represents the distribution of behaviors empirically determined from the controlled experimental replications. If all of the flakes produced at a site were produced in a least effort manner and were still present at the site when it was excavated, the archaeological distribution is expected to be similar to that of the experimental distribution. The second distribution is archaeological and classified via the classification algorithm Fig 4. However, each flake classified via this algorithm has a misclassification statistic associated with it (Table 2). Therefore, the third distribution (“Max OBD and OBB”) and the fourth distribution (“Max OBC and OBA”) demonstrate the potential extremes of the archaeological distribution given these misclassification rates. Finally, the last distribution (“Range of Variation”) combines the second, third, and fourth distributions into one combined statistic. For each bar on the graph, the dark colors represent the potential range of representation for that production behavior, given the potential misclassifications outlined in Table 2. The line inside the colored box represents the actual archaeological value, given classification via Fig 4. If no line is present in the colored box, then either the upper or lower extreme is the actual classified value. (Chi-square results: Expected vs. DK: Yates’ chi-square = 8.58, df = 1, Yates’ p = <0.01).