Dept. d'Enginyeria Química, Universitat Rovira i Virgili, Tarragona, Spain.
PLoS One. 2013 May 28;8(5):e58989. doi: 10.1371/journal.pone.0058989. Print 2013.
Social groups of interacting agents display an ability to coordinate in the absence of a central authority, a phenomenon that has been recently amplified by the widespread availability of social networking technologies. Models of opinion formation in a population of agents have proven a very useful tool to investigate these phenomena that arise independently of the heterogeneities across individuals and can be used to identify the factors that determine whether widespread consensus on an initial small majority is reached. Recently, we introduced a model in which individual agents can have conservative and partisan biases. Numerical simulations for finite populations showed that while the inclusion of conservative agents in a population enhances the population's efficiency in reaching consensus on the initial majority opinion, even a small fraction of partisans leads the population to converge on the opinion initially held by a minority. To further understand the mechanisms leading to our previous numerical results, we investigate analytically the noise driven transition from a regime in which the population reaches a majority consensus (efficient), to a regime in which the population settles in deadlock (non-efficient). We show that the mean-field solution captures what we observe in model simulations. Populations of agents with no opinion bias show a continuous transition to a deadlock regime, while populations with an opinion bias, show a discontinuous transition between efficient and partisan regimes. Furthermore, the analytical solution reveals that populations with an increasing fraction of conservative agents are more robust against noise than a population of naive agents because in the efficient regime there are relatively more conservative than naive agents holding the majority opinion. In contrast, populations with partisan agents are less robust to noise with an increasing fraction of partisans, because in the efficient regime there are relatively more naive agents than partisan agents holding the majority opinion.
社交群体中的互动代理在没有中央权威的情况下表现出协调能力，这种现象最近由于社交网络技术的广泛普及而得到增强。在代理人群体中形成意见的模型已被证明是一种非常有用的工具，可以研究这些独立于个体异质性而出现的现象，并可用于确定决定是否在初始的小多数人中达成广泛共识的因素。最近，我们引入了一个模型，其中个体代理可以具有保守和党派偏见。对于有限的人群进行数值模拟表明，尽管在人群中包含保守派代理可以提高人群在初始多数意见上达成共识的效率，但即使只有一小部分党派人士也会导致人群最初倾向于少数人的意见。为了进一步了解导致我们之前的数值结果的机制，我们分析研究了由群体达到多数共识（有效）的状态向群体陷入僵局（无效）的状态的噪声驱动转变。我们表明，平均场解决方案可以捕获我们在模型模拟中观察到的内容。没有意见偏见的代理人群体显示出向僵局状态的连续转变，而具有意见偏见的代理人群体则显示出在有效和党派状态之间的不连续转变。此外，分析解决方案揭示了具有越来越多保守派代理的群体比具有天真代理的群体对噪声更具鲁棒性，因为在有效状态下，持有多数意见的相对保守的代理比天真的代理更多。相比之下，具有党派代理的群体在越来越多的党派代理存在时对噪声的鲁棒性较低，因为在有效状态下，持有多数意见的相对天真的代理比党派代理更多。
