Human Evolution and the Origins of Hierarchies: The State of Nature

great, did not finish

Benoît Dubreuil says that he agrees with an anthropological view that `political hierarchies have followed a U-shaped trajectory during human evolution, disappearing during the Palaeolithic and reappearing during the Neolithic.' His detailed argument, though, shows that the second type of hierarchy emphatically was not a reappearance of the first type but an analogous product of a different mechanism, and that it emerged before the Neolithic. This detail does not affect his mission, which is to resolve the apparent paradox that the hominid brain, increasing in capacity over a period of two million years could at first find hierarchy to be necessary, then abolish it, then find it to be essential again.

His chronology starts with the common ancestor of chimpanzee and man, which by wide agreement was an animal with a social structure based on overt physical aggression in which group members enforced their privileged access to food and mating rights. It is this bullying that disappeared in the Palaeolithic. He produces evidence that by the time of Homo erectus, about 1.8 mya (million years ago) man was a cooperative hunter-gatherer systematically sharing food. His evidence comes from studies of recent pure hunter-gatherer communities, and from tool use and cranial development (which he has studied in detail) in the archaeological record. He proposes that what caused our pacification was the increase in cognitive ability that allowed the group to share goals and `sanction' alpha males or would-be contenders for the title -a chilling hint at assassination for those who remember The Eiger Sanction. In a striking phrase Dubreuil says that until further development of the brain mankind was `condemned to equality' by limited cognitive ability. He seems to mean only that Homo erectus was not intellectually able to form larger and (he thinks) necessarily hierarchical groups.

Dubreuil explicitly uses Robin Dunbar's discovery of neocortex size correlation with group size to support his analysis, but rejects the idea that the extra grey matter might be used for group-specific functions before Homo sapiens arrived about 0.2 mya. For example he rejects an emerging `Theory of Mind' as an explanation of the move to non-dominance before then on the grounds that it also requires sub-cortical structures and that `there is no indication that it increases linearly with brain size'. This appears to be his justification for his assumption that the brain's Theory of Mind capability arrived in one jump with Homo sapiens - a big assumption. A more general cognition is Dubreuil's explanation of social advances before then. The food sharing of Homo erectus was, in his view, enabled by attention-sharing and imposed by the conscious development of norms and sanctions. After a further increase in brain size at the time of Homo Heidelbergensis 0.8 mya these norms and sanctions were extended to cooperative breeding arrangements, e.g. the evolution of pair bonding enabling infants to be born helpless. Size advantages of male over female had diminished rapidly, a telling indicator that innate male bullying of other males and females for sexual access had ceased. According to Dubreuil, the arrival of Homo sapiens (c.0.2 mya) with additional brain functionality, theory of mind, and a capacity to attach meaning to symbols finally freed humankind from the bondage of equality, so to speak. A new type of hierarchy emerged which allowed individuals to delegate enforcement of norms and sanctions to hierarchical superiors who imposed them on a populace now too large to be policed by individual members. The system required a use of symbols to distinguish different levels in the hierarchy. Dubreuil holds that the larger hierarchically-controlled populations created more opportunities for innovation and creativity, laying the foundation for the creative explosion. The sources he quotes (Richerson and Boyd, Shennan) certainly indicate that larger populations can facilitate innovation, but there is plenty of evidence supporting the Weberian view that authoritarian hierarchy inhibits it. This evidence weakens Dubreuil's argument that artistic symbolism is the sign of a newborn authoritarian hierarchy. It also conflicts with the anthropological view that he quotes to the effect that hierarchy only reappeared later, during the Neolithic.

The most recent possible date (45,000 years ago) for the start of the creative explosion, which Dubreuil attributes to an innovative superiority of hierarchical organisation, is long before the start of the Neolithic. If there was a hierarchy in the Palaeolithic it may have been of a much less authoritarian type, not a `modern' one of the type that is usually thought to have emerged only after the arrival of Neolithic agriculture 10,000 years ago. The linkage between hierarchy and the Neolithic transition is strong, because only agriculture could provide the long-term storage that allowed rulers and priests to be maintained out of the surplus and to control production through centralised expertise. Dubreuil notes that food-storing hunter-gatherers such as Northwest Coast Indians exhibit greater inequality than pure foragers, and that less authoritarian `rank societies' exist in which the hierarchy controls access to prestige goods but (unlike agricultural societies) not to critical subsistence resources. This is surely a more likely accompaniment of symbolism and creativity than the `delegated sanctioning' (i.e. authoritarian) hierarchy which Dubreuil proposes. He examines at length the various theories of how primitive hierarchies evolved into states, and while agreeing that no state has ever emerged without agriculture he does not find it a sufficient cause. But he makes clear that his goal is not to find an explanation for the advance to statehood but to identify cognitive and motivational factors, the most salient of the latter being in his view the gratitude felt at each level for the exertions of the level above. By limiting his scope he may make the increasing reasoning power of individuals appear to account for the strange pre-Neolithic decline and rise of hierarchy, but he leaves the latest chapter in the biography of human hierarchy unwritten. Hierarchy is an organisation that creates itself in many places in the universe, and the latest chapter might reveal a kind of hierarchy that emerged too recently to have been hardwired into the brain.