Some new research has been added to the pile of work purporting to show that human warfare is a relatively recent development. Somehow, we've arrived at a strange point in the history of speculation on 'human nature', where the 'conservatives', such as Steven Pinker, wish to argue that war has primal roots in human evolution, and that we share our bellicosity even with other primate species such as chimpanzees. Thus, to the question, for how long have human beings been war-makers? their answer is: at least since what would later become Pan troglodytes and Homo sapiens both split from their common ancestor between 5 and 7 million years ago. The 'progressives', in turn, say that war is a recent development and an indication that human society has at some not-too-distant point taken a turn for the worse.
The latest study favouring the 'progressives', like all work in this genre, takes for granted that war and violence are by definition an intra-species affair. Aristotle seems to be one of the few authors ever to have understood that 'hunting is a form of war' (Politics Bk. 10), and we would do well to learn from him. In the time-period and region described in the study (Japan, 7,000-12,000 years ago), that war had by no means been decisively won by human beings, though it will have been by the time of the foundation of city-states (which are among other things barriers against the encroachment of other top predators). There is something astoundingly oxymoronic about the claim that 'hunter-gatherers were not violent', as if, e.g., shedding the blood of bears had nothing in common with human-on-human bloodshed. This separation of the two sorts of activity presupposes an ontological and moral divide between animals and human beings, which there is no evidence Palaeolithic human beings shared with us. It seems more correct to say that human warfare really gets going at the moment human domination of other megafauna becomes certain and total, which is, not coincidentally, also the beginning of the period of urbanisation and animal domestication. However much we would like to go it alone, political theory and debate about 'human nature' simply cannot be done without taking seriously the role of non-human animals in human political life.
Both sides are wrong, since both sides are operating with a definition of violence that really only makes sense on the presupposition of human exceptionalism, which seems to be the product of a rather late-coming and parochial ontology.