Title: Emergent Group-Level Selection in a Peer-to-Peer Network

Many peer-to-peer (P2P) applications benefit from node specialisation. For example, the use of supernodes, the semantic clustering of media files or the distribution of different computing tasks among nodes. We describe simulation experiments with a simple selfish re-wiring protocol (SLAC) that can spontaneously self-organise networks into internally specialized groups (or “tribes”). Peers within the tribes pool their specialisms, sharing tasks and working altruistically as a team – or “tribe” even though their individual behaviour is selfish. This approach is scalable, robust and self-organising. These results have implications and applications in many disciplines and areas beyond P2P systems.