题目：A Theory of Multiplexity: Sustaining Cooperation with Multiple Relations

演讲者：邢亦青（约翰-霍普金斯大学）

时间：6月2日（周三）下午2：00-3：30

地点：北京大学国家发展研究院（朗润园）512教室

摘要：People are embedded in multiple social relations. These relations are not isolated from each other. Do different networks overlap and why? We focus on the following question: When an agent has a new relation to add, would they choose to multiplex, i.e., to link with a friend or a stranger? The key tradeoff that we emphasize is the one between multiplexity and community enforcement. Multiplexity enhances cooperation because various relations serve as social collateral for each other, while linking to a stranger can utilize community enforcement, whose power relies more on the rest of the network structure. We find the following: (1) There is a strong tendency to multiplex, and the “multiplexity trap” can occur; that is, agents may keep adding relationships with friends, even when it is more efficient to link with a stranger. (2) Agents tend to multiplex when the existing network (a) has a low degree dispersion (i.e., all agents have similar numbers of friends) or (b) is positively assortative (agents are linked with those with a similar number of friends). We also find that agents tend to multiplex when the new relationship is more important. Using the Indian Village Survey data, we provide supportive evidence for our theoretical predictions.

演讲人介绍：邢亦青，美国约翰-霍普金斯大学助理教授。北京大学数学学士、经济学双学士、硕士（CCER）；斯坦福大学经济学博士，师从马修-杰克逊教授。主要研究兴趣为网络经济学、微观经济理论、发展经济学等。论文发表于PNAS、EER、经济研究等中英文期刊。为AER、Econometrica、QJE、PNAS、Nature、JASA等20余种期刊担任匿名审稿人。