“Friends Are Thieves of Time”: Heuristic attention sharing in stable friendship networks
研究了人们按“更关注朋友少的邻居”这一简单规则建立友谊网络时，会产生聚类、核心-边缘等现实特征，且稳定网络福利接近最优。
This paper studies a model of network formation in which agents create links following a simple heuristic — they invest their limited resources proportionally more in neighbours who have fewer links. This decision rule captures the notion that when considering social value more connected agents are on average less beneficial as neighbours and node degree is a useful proxy when payoffs are difficult to compute. The decision rule illustrates an externalities effect whereby an agent’s actions also influence his neighbours’ neighbours. Besides complete networks and fragmented networks with complete components, the pairwise stable networks produced by this model include many non-standard ones with characteristics observed in real life networks like clustering and irregular components. Multiple stable states can develop from the same initial structure — the stable networks could have cliques linked by intermediary agents while sometimes they have a core–periphery structure. The observed pairwise stable networks have close to optimal welfare. This limited loss of welfare is due to the fact that when a link is established, this is beneficial to the linking agents, but makes them less attractive as neighbours for others, thereby partially internalising the externalities the new connection has generated. • A network formation model of heuristic allocation of scarce resources is proposed. • Besides networks of complete components, many non-standard networks are pairwise stable. • The observed pairwise stable networks have close to optimal welfare. • The pairwise stable networks exhibit clustering and can have irregular components. • The stable networks can have cliques linked by intermediaries or a core–periphery structure.