Data from: Collective decision making in guppies: a cross-population comparison study in the wild

Collective cognition has received much attention in recent years but most of the empirical work has focused on comparing individuals and groups within single populations, thereby not addressing evolutionary origins of collective cognition. Here we investigated collective cognition in multiple populations that are subject to different levels of predation. Guppies (Poecilia reticulata) were given a simultaneous choice between an edible and a non-edible stimulus. We found evidence for an improvement in decision accuracy when in groups but only in low-predation guppies. This performance increase was due to a combination of increased private sampling behaviour when in groups (compared to being alone) and social information use. In contrast, high-predation fish did not sample more when in groups, nor used social information; hence did not improve decision-accuracy when in groups. The improvement of groups in foraging accuracy in low but not in high predation sites, suggests that these populations differ in their trade-off between attention dedicated to food and predators. In high predation sites, investing time in predator detection is more crucial than in low predation sites, thereby possibly conflicting with food detection. Our results highlight the importance of considering the effects of ecological gradients on collective cognition.近年来，群体认知（collective cognition）受到学界广泛关注，但绝大多数实证研究均聚焦于单一种群内个体与群体的对比分析，未能探讨群体认知的进化起源。本研究针对受不同捕食压力的多个种群开展群体认知相关实验。实验以孔雀鱼（Poecilia reticulata）为对象，设置可食用与不可食用两类刺激物，令其同时进行选择。结果显示，仅在低捕食压力种群的孔雀鱼中，群体环境下的决策准确率得到显著提升。该性能提升源于两方面因素的协同作用：相较于独处状态，群体环境下个体的私人采样行为有所增加，同时个体对社会信息的利用更为充分。与之形成鲜明对比的是，高捕食压力种群的孔雀鱼在群体中并未增加采样行为，也未利用社会信息，因此群体环境下其决策准确率未获提升。低捕食压力种群的群体觅食准确率有所改善，而高捕食压力种群则无此现象，这表明两类种群在分配注意力于觅食与捕食者探测之间存在权衡差异。在高捕食压力环境中，投入时间探测捕食者比低捕食压力环境更为关键，因此该行为可能与食物探测产生冲突。本研究结果凸显了考量生态梯度对群体认知影响的重要性。