Collective behavior can be notoriously hard to predict. We revisited a possible explanation suggested by Granovetter’s classic threshold model: collective behavior can unexpectedly fail, despite a group’s strong interest in the outcome, because of the sensitivity of cascades to small random perturbations in group composition and the distribution of thresholds. Paradoxically, we found that a small amount of randomness in individual behavior can make collective behavior less sensitive to these perturbations and therefore more predictable. We also examined conditions in which collective behavior unexpectedly succeeds despite the group’s weak interest in the outcome. In groups with an otherwise intractable start-up problem, individual randomness can lead to spontaneous instigation, making outcomes more sensitive to the strength of collective interests and therefore more predictable. These effects of chance behavior become much more pronounced as group size increases. Although randomness is often assumed to be a theoretically unimportant residual category, our findings point to the need to bring individual idiosyncrasy back into the study of collective behavior.

中文翻译：

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集体行为的阈值模型 II：可预测性悖论和自发煽动

众所周知，集体行为很难预测。我们重新审视了 Granovetter 的经典阈值模型提出的一个可能的解释：尽管一个群体对结果非常感兴趣，但由于级联对群体组成和阈值分布中的小随机扰动的敏感性，集体行为可能会意外失败。矛盾的是，我们发现个人行为中的少量随机性可以使集体行为对这些扰动不那么敏感，因此更可预测。我们还检查了集体行为出人意料地成功的条件，尽管该小组对结果的兴趣不大。在具有其他难以解决的启动问题的群体中，个体随机性会导致自发的煽动，使结果对集体利益的强度更敏感，因此更可预测。随着群体规模的增加，这些偶然行为的影响变得更加明显。尽管随机性通常被认为是理论上不重要的剩余类别，但我们的研究结果表明需要将个人特质带回集体行为的研究中。