School of Biological Sciences, University of Sydney, Sydney, NSW 2006, Australia.
Proc Natl Acad Sci U S A. 2011 Feb 8;108(6):2312-5. doi: 10.1073/pnas.1007102108. Epub 2011 Jan 24.
Although it has been suggested that large animal groups should make better decisions than smaller groups, there are few empirical demonstrations of this phenomenon and still fewer explanations of the how these improvements may be made. Here we show that both speed and accuracy of decision making increase with group size in fish shoals under predation threat. We examined two plausible mechanisms for this improvement: first, that groups are guided by a small proportion of high-quality decision makers and, second, that group members use self-organized division of vigilance. Repeated testing of individuals showed no evidence of different decision-making abilities between individual fish. Instead, we suggest that shoals achieve greater decision-making efficiencies through division of labor combined with social information transfer. Our results should prompt reconsideration of how we view cooperation in animal groups with fluid membership.
虽然有人认为大型动物群体应该比小型群体做出更好的决策，但很少有经验证据证明这一现象，更少有解释这些改进是如何实现的。在这里，我们表明，在捕食威胁下，鱼类群体的决策速度和准确性都随着群体规模的增加而提高。我们研究了两种可能的改进机制：第一，群体由一小部分高质量的决策者指导；第二，群体成员使用自我组织的警戒分工。对个体的反复测试没有表明个体鱼之间的决策能力有差异。相反，我们认为，通过劳动分工和社会信息传递相结合，鱼群可以实现更高的决策效率。我们的研究结果应该促使人们重新考虑如何看待具有流动性成员的动物群体中的合作。
