University Grenoble Alpes, CNRS, LIPhy, F-38000, Grenoble, France.
University Grenoble Alpes, CNRS, LPNC, F-38000, Grenoble, France.
Sci Rep. 2023 Jul 20;13(1):10414. doi: 10.1038/s41598-023-36869-9.
Crowd movements are observed among different species and on different scales, from insects to mammals, as well as in non-cognitive systems, such as motile cells. When forced to escape through a narrow opening, most terrestrial animals behave like granular materials and clogging events decrease the efficiency of the evacuation. Here, we explore the evacuation behavior of macroscopic, aquatic agents, neon fish, and challenge their gregarious behavior by forcing the school through a constricted passage. Using a statistical analysis method developed for granular matter and applied to crowd evacuation, our results clearly show that, unlike crowds of people or herds of sheep, no clogging occurs at the bottleneck. The fish do not collide and wait for a minimum waiting time between two successive exits, while respecting a social distance. When the constriction becomes similar to or smaller than their social distance, the individual domains defined by this cognitive distance are deformed and fish density increases. We show that the current of escaping fish behaves like a set of deformable 2D-bubbles, their 2D domain, passing through a constriction. Schools of fish show that, by respecting social rules, a crowd of individuals can evacuate without clogging, even in an emergency situation.
人群的移动在不同的物种和不同的尺度上都有观察到，从昆虫到哺乳动物，以及在非认知系统中，如游动细胞。当被迫通过狭窄的开口逃生时，大多数陆地动物的行为就像粒状物质一样，如果堵塞事件发生，会降低疏散的效率。在这里，我们研究了宏观的水生生物——霓虹鱼的疏散行为，并通过迫使鱼群通过狭窄的通道来挑战它们的群居行为。我们使用一种针对颗粒物质开发的统计分析方法，并将其应用于人群疏散，结果清楚地表明，与人群或羊群不同，在瓶颈处不会发生堵塞。鱼不会相互碰撞，并且在连续两次通过瓶颈的最小等待时间之间等待，同时还保持社交距离。当瓶颈变得与它们的社交距离相似或更小，由这种认知距离定义的个体区域就会变形，并且鱼的密度增加。我们表明，逃生的鱼群的流动就像一组可变形的 2D 气泡，它们的 2D 区域通过狭窄的通道。鱼群表明，通过遵守社会规则，即使在紧急情况下，一群个体也可以避免堵塞而疏散。
