Data from: Potential leaders trade off goal-oriented and socially-oriented behavior in mobile animal groups

Leadership is widespread across the animal kingdom. In self-organizing groups, such as fish schools, theoretical models predict that effective leaders need to balance goal-oriented motion, such as toward a known resource, with their tendency to be social. Increasing goal orientation is predicted to increase decision speed and accuracy, but it is also predicted to increase the risk of the group splitting. To test these key predictions, we trained fish (golden shiners, Notemigonus crysoleucas) to associate a spatial target with a food reward (“informed” individuals) before testing each singly with a group of eight untrained fish who were uninformed (“naive”) about the target. Informed fish that exhibited faster and straighter paths (indicative of greater goal orientation) were more likely to reach their preferred target and did so more quickly. However, such behavior was associated with a tendency to leave untrained fish behind and, therefore, with failure to transmit their preference to others. Either all or none of the untrained fish stayed with the trained fish in the majority of trials. Using a simple model of self-organized coordination and leadership in groups, we recreate these features of leadership observed experimentally, including the apparent consensus behavior among naive individuals. Effective leadership thus requires informed individuals to appropriately balance goal-oriented and socially oriented behavior.动物界中普遍存在领导行为。在鱼群这类自组织群体中，理论模型预测，高效的领导者需要在目标导向运动（例如朝向已知资源的移动）与自身社交倾向之间取得平衡。目标导向性的提升虽可加快决策速度、提升决策准确性，但同时也会增加群体分裂的风险。为验证这些核心预测，我们以金体美洲鳊鱼（golden shiners，*Notemigonus crysoleucas*）为实验对象：先训练个体将空间目标与食物奖励建立关联，此类个体被称为「知情个体（informed individuals）」；随后将单只训练过的鱼与8只对目标一无所知的未训练个体（被称为「无知个体（naive individuals）」）组成群体进行测试。那些游动路径更快捷、更笔直的知情个体（这一特征代表更高的目标导向性），更有可能抵达偏好目标，且抵达速度更快。但这类行为会导致未训练个体被甩在后方，因此无法将自身的目标偏好传递给群体其他成员。在绝大多数实验试次中，未训练个体要么全程跟随训练过的鱼，要么完全不跟随。我们通过一套简单的群体自组织协调与领导行为模型，复现了实验中观察到的领导行为特征，包括无知个体间呈现出的表观共识行为。由此可见，高效的群体领导需要知情个体在目标导向行为与社交导向行为之间做出恰当平衡。