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.集体认知（collective cognition）近年来受到学界广泛关注，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，因而未能阐释集体认知的演化起源。本研究针对受不同捕食压力的多个种群展开集体认知相关探究，实验对象为孔雀花鳉（Poecilia reticulata），需同时在可食用刺激物与不可食用刺激物间做出选择。研究结果显示，仅在低捕食压力种群的孔雀花鳉中，群体环境下的决策准确率得以提升；该性能提升源于两方面因素的共同作用：一是群体环境下相较于独处时个体的私人采样行为增多，二是对社会信息的利用。与之相反，高捕食压力种群的花鳉在群体环境下并未增加采样行为，也未利用社会信息，因此群体状态下其决策准确率未得到提升。低捕食压力环境中群体觅食准确率得以提升，而高捕食压力环境中则无此现象，这表明两类种群在分配注意力于觅食与捕食者警戒间存在权衡差异。在高捕食压力环境中，花鳉投入时间进行捕食者警戒的优先级高于低捕食压力环境，这可能与食物搜寻存在冲突。本研究结果凸显了考量生态梯度对集体认知影响的重要性。