Department of Physics and State Key Laboratory of Surface Physics, Fudan University, Shanghai 200433, China.
Proc Natl Acad Sci U S A. 2011 Sep 13;108(37):15058-63. doi: 10.1073/pnas.1105239108. Epub 2011 Aug 29.
In order to survive, self-serving agents in various kinds of complex adaptive systems (CASs) must compete against others for sharing limited resources with biased or unbiased distribution by conducting strategic behaviors. This competition can globally result in the balance of resource allocation. As a result, most of the agents and species can survive well. However, it is a common belief that the formation of a herd in a CAS will cause excess volatility, which can ruin the balance of resource allocation in the CAS. Here this belief is challenged with the results obtained from a modeled resource-allocation system. Based on this system, we designed and conducted a series of computer-aided human experiments including herd behavior. We also performed agent-based simulations and theoretical analyses, in order to confirm the experimental observations and reveal the underlying mechanism. We report that, as long as the ratio of the two resources for allocation is biased enough, the formation of a typically sized herd can help the system to reach the balanced state. This resource ratio also serves as the critical point for a class of phase transition identified herein, which can be used to discover the role change of herd behavior, from a ruinous one to a helpful one. This work is also of value to some fields, ranging from management and social science, to ecology and evolution, and to physics.
为了生存，各种复杂适应系统（CAS）中的自利主体必须通过策略行为与其他主体竞争，以获得具有偏置或无偏置分布的有限资源的共享。这种竞争可以全局导致资源分配的平衡。结果，大多数主体和物种都可以很好地生存。然而，人们普遍认为，CAS 中的羊群形成会导致过度波动，从而破坏 CAS 中的资源分配平衡。在这里，我们利用从建模资源分配系统中获得的结果来挑战这种信念。基于这个系统，我们设计并进行了一系列包括羊群行为在内的计算机辅助人类实验。我们还进行了基于主体的模拟和理论分析，以确认实验观察结果并揭示潜在的机制。我们报告说，只要分配的两种资源的比例存在足够的偏差，典型规模的羊群的形成就可以帮助系统达到平衡状态。这个资源比例也可以作为一个相转变的临界点，它可以用来发现羊群行为的角色变化，从破坏性的到有益的。这项工作对于从管理和社会科学到生态学和进化学以及物理学等领域也具有重要意义。
