According to cultural anthropologist and ethnographer Raymond C. Kelly, the earliest hunter-gatherer societies of Homo erectus population density was probably low enough to avoid armed conflict. The development of the throwing-spear, together with ambush hunting techniques, made potential violence between hunting parties very costly, dictating cooperation and maintenance of low population densities to prevent competition for resources. This behavior may have accelerated the migration out of Africa of H. erectus some 1.8 million years ago as a natural consequence of conflict avoidance.
Some scholars believe that this period of "Paleolithic warlessness" persisted until well after the appearance of Homo sapiens some 200,000 years ago, ending only at the occurrence of economic and social shifts associated with sedentism, when new conditions incentivized organized raiding of settlements.
Of the many cave paintings of the Upper Paleolithic, none depict people attacking other people explicitly,
but there are depictions of human beings pierced with arrows
both of the Aurignacian-Périgordian (roughly 30,000 years old) and the early Magdalenian (c. 17,000 years old), possibly representing "spontaneous confrontations over game resources" in which hostile trespassers were killed, but other interpretations, including capital punishment, human sacrifice, assassination or systemic warfare cannot be ruled out.
Skeletal and artifactual evidence of intergroup violence between Paleolithic nomadic foragers is absent as well.