On the origin of forager bands
This analysis suggests that the transition from the closed social worlds characteristic of the great apes species to open bands nested in a larger community began quite early, with the erectines or the more clearly apex hunters, the Heidelbergensians (Stiner 2002). Layton and his colleagues suggest that long distance raw material transport is a proxy for more open networks. If raw material movement regularly and comfortably exceeds the plausible daily movement limits of a band, the social world is probably open enough to allow material resources to flow from one band to another, or for bands to allow movement by others into their territories to harvest stone or ochre (Layton and O’Hara 2010, Layton, O’Hara et al. 2012). This proxy suggests a quite deep origin of open-textured social organization, probably with the Heidelbergensians (about 800 kya).
Kim Sterelny, The Pleistocene Social Contract, p. 108