Throwing Behaviour and the Mass Distribution of Geological Hand Samples,Hand Grenades and Olduvian Manuports

This research examines the efficiency of impact energy delivered by a thrown rock and the relationship between the mechanics of throwing and how rocks are chosen. This choice tends to lead to a Poisson distribution of mass with different means for men and women. These values are reflected in the mass of hand samples selected by geologists, in the throwing stones made in the last century by the Nuie Islanders, in the sport of handball and in the design of hand grenades. When the mass distributions of manuports from Olduvai and Koobi Fora are examined two very different mass distributions can be seen: one indicating a probable selection by larger creatures of almost modern human size, the other by creatures that were far smaller. Observations of Olduvian cobble tools indicate that their mass distribution is similar to the manuports hoarded by the larger hominids. A simple engineering model links the mass distribution of selected rocks to body size and it is suggested that this technique can be used to reveal sexual differences in cobble tool making and any differences in body size during the development of the Olduvian industry or at distinct geographical sites. Perhaps the most intriguing use of this technique, however, is in the examination of the mass and form of stone deposits laid down before stone tools were manufactured. A specific clustering would indicate, within a certain degree of statistical probability, the deliberate selection and hoarding by a hominid species that used the systematic hurling of rocks as a behavioural strategy. In this case, stone tools would represent an improvement on an object of the same mass and material that had been part of an earlier culture.