Resumen de Mass Distribution Analysis of Spheroid Manuports, Spheroid Artifacts, and the Lithics of Play Learning
The mass distribution of the natural spheroids (manuports) from the Cave of Hearths, South Africa, is examined and found to empirically match a Poisson-type histogram with an average of 533 g. The stature of the (male) hominins that hoarded this cache is modeled at 181 cm, compatible with the fossil record for this region and period. This empirical distribution is shown to be partly a consequence of a visual selection of throwing material. The ethnological case of the war stones from the Niue Islands is examined in terms of their use and mass, showing that their distribution is similar to that of the Cave of Hearths and validating the interpretation that these manuports were collected for throwing. An examination of other spheroid artifacts reveals similar mass distributions, indicating that they also may have been made for throwing (or that our attraction to good throwing material determined their mass). The surprisingly overlooked question of play-learning is discussed, together with the possibility that smaller stones and artifacts were hoarded by juveniles at certain sites.
