Collective computation and the emergence of hunter-gatherer small-worlds

Abstract

Two defining features of human sociality are large brains with neurally-dense cerebral cortices and the propensity to form complex social networks with non-kin. Large brains and the social networks in which they are embedded facilitate flows of fitness-enhancing information at multiple scales, but are also energetically expensive. In this paper, we consider how flows of energy and information interact to shape the macroscopic features of hunter-gatherer socioecology. Collective computation is the processing of information by complex adaptive systems to generate inferences in order to solve adaptive problems. In hunter-gatherer societies the adaptive problem is how to maximize fitness by optimizing information processing given the energy constraints of complex environments. The solution is the emergent macroscopic structure of the socioecology. Here, we show how computation is extended across social networks to form the decentralized knowledge systems characteristic of hunter-gatherer societies. Data show that hunter-gatherer bands of co-residing families constitute computationally powerful networks that are embedded within hierarchically modular social networks that form complex metapopulations bound by fission-fusion dynamics at multiple scales facilitating the flow of information far beyond local interactions. These dynamics lead to the emergence of hunter-gatherer small-worlds where highly clustered local interactions are embedded within much larger, but sparsely connected metapopulations. Hunter-gatherers optimize local energy budgets in small groups but maintain interactions with much larger social net-works while avoiding many of the ecological costs.

Understanding hunter–gatherer cultural evolution needs network thinking

“…The analysis of worldwide ethnographic datasets recurrently finds this nested self-similar structure characteristic of small-world, hierarchically modular networks. The information flow leads to the emergence of small-world networks where highly clustered local interactions are embedded within much larger but sparsely connected multilevel metapopulations forming decentralized knowledge systems [4]. Depicted networks have been produced by a network model combining constraints on module size at each hierarchical level and random wiring of links among families/nodes.…”

“…Furthermore, features such as coresidence, cooperation with unrelated individuals, multilocality, fluid sociality, and high between-camp mobility might have had a major influence on the cognitive mechanisms (e.g., high-fidelity transmission, innovation, teaching, and combinatorial innovation) underlying cumulative cultural evolution. This research has significantly contributed to replacing the long-held view of huntergatherers living in small-scale societies by a new perspective that highlights how small coresidence groups are dynamically connected to much larger populations, forming expansive networks of social interaction at large spatial scales [3,4]. In spite of contributing to a paradigm shift, experimental and ethnographic studies do not have the time depth to reveal how these changes might have impacted cultural evolution across generations.…”