复杂传染
Complex contagion is the phenomenon in social networks in which multiple sources of exposure to an innovation are required before an individual adopts the change of behavior. Centola and Macy show that the weak ties and small worlds networks are both very good for spreading simple contagions. However, for complex contagions, weak ties and small worlds can slow diffusion.
复杂传染 Complex contagion是社会网络中的一种现象，在社会网络中，一个人或一个个体需要受到多种不同的影响，会对自身行为采取改变。[1] 不同于疾病的简单传染，邻居单一的一次接触并不会使其成功传染，复杂传染的传播需要人群网络中复杂交错的社会和经济因素。例如，一个人有多少个朋友接受这个新想法，以及这些朋友能不能影响这个人，以及他们自己接受改变的倾向。Centola和Macy表明，弱联系和小世界网络都非常有利于简单传播的传染病。然而，对于复杂传染，弱联系和小世界可以有效减缓扩散。
传播机制
These properties explain the need for multiple exposures in the spread of contagion:
Centola和Macy梅西提出了四种复杂传染的机制。这些性质解释了在传染过程中为什么需要多重曝光：
Complex Contagion and the Weakness of Long Ties by Damon Centola of University of Pennsylvania and Michael Macy of Cornell University found that information and disease spread as “simple contagions”, requiring only one contact for transmission, while behaviors typically spread as “complex contagions”, requiring multiples sources of reinforcement to induce adoption. Centola’s work builds on Granovetter’s work on the strength of weak ties and threshold models of collective behavior, as well as Duncan Watts and Steve Strogatz’s work on small world networks.[2] Centola and Macy show that the weak ties and small worlds networks are both very good for spreading simple contagions. However, for complex contagions, weak ties and small worlds can slow diffusion.
Strategic complementarity. Many innovations are costly, especially for early adopters but less so for those who wait. The same holds for participation in collective action.
战略互补性。许多创新成本高昂，尤其是对于早期采用者，但对于那些等待的人来说成本较低。参与集体行动也是如此。
Centola and Macy suggest four mechanisms of complex contagion. These properties explain the need for multiple exposures in the spread of contagion:
Credibility. Innovations often lack credibility until adopted by neighbors. Hearing the same story from different people makes it seem less likely that surprising information is nothing more than the fanciful invention of the informant.
可信度。创新往往缺乏可信度，直到被邻居采用。从不同的人那里听到同样的故事，使得令人惊讶的信息不过是线人幻想出来的东西的可能性降低了。
Legitimacy. Knowing that a movement exists or that a collective action will take place is rarely sufficient to induce bystanders to join in. Having several close friends participate in an event often greatly increases an individual’s likelihood of also joining, especially for high-risk social movements. Innovators risk being shunned as deviants until there is a critical mass of early adopters, and non-adopters are likely to challenge the legitimacy of the innovation.
合法性。知道一个运动的存在或者一个集体行动将要发生，很少足以诱使旁观者加入进来。有几个亲密的朋友参加一个活动通常会大大增加一个人加入的可能性，特别是对于高风险的社会运动。创新者可能会被当作异类回避，直到有足够数量的早期采用者，而非采用者可能会挑战创新的合法性。
- Strategic complementarity. Many innovations are costly, especially for early adopters but less so for those who wait. The same holds for participation in collective action.
Emotional contagion. Most theoretical models of collective behavior – from action theory to threshold models to cybernetics share the basic assumption that there are expressive and symbolic impulses in human behavior that can be communicated and amplified in spatially and socially concentrated gatherings.
情绪感染。从行动理论到门槛模型再到控制论，大多数集体行为的理论模型都有一个共同的基本假设，即人类行为中存在着表达冲动和象征冲动，这些冲动可以在空间和社会集中的集会中得到沟通和放大。
- Credibility. Innovations often lack credibility until adopted by neighbors. Hearing the same story from different people makes it seem less likely that surprising information is nothing more than the fanciful invention of the informant.
- Legitimacy. Knowing that a movement exists or that a collective action will take place is rarely sufficient to induce bystanders to join in. Having several close friends participate in an event often greatly increases an individual’s likelihood of also joining, especially for high-risk social movements. Innovators risk being shunned as deviants until there is a critical mass of early adopters, and non-adopters are likely to challenge the legitimacy of the innovation.
- Emotional contagion. Most theoretical models of collective behavior – from action theory to threshold models to cybernetics share the basic assumption that there are expressive and symbolic impulses in human behavior that can be communicated and amplified in spatially and socially concentrated gatherings.[1]
Contested vs. uncontested
- Uncontested
- The spread of the contagion is dependent solely on the number of people you are connected to who are different from your own state. You are not hindered whatsoever by the number of people in the same state as you. Generally, the more neighbors an individual has, the greater the chance of the individual adopting the innovation if the spread is uncontested.[1]
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- Contested
- The spread of the contagion is dependent on both the adamancy of those who are in a different state from your own as well as the countervailing influence of those who share your current state. In this case, the more neighbors an individual has, the smaller the chance of the individual adopting the innovation.[1]
Category:Social networks
分类: 社交网络
This page was moved from wikipedia:en:Complex contagion. Its edit history can be viewed at 复杂传染/edithistory