Animals can indirectly gather meaningful information about other individuals by eavesdropping on their third-party interactions. In particular, eavesdropping can be used to indirectly attribute a negative or positive valence to an individual and to adjust one’s future behavior towards that individual. Few studies have focused on this ability in nonhuman animals, especially in nonprimate species. Here, we investigated this ability for the first time in domestic horses (Equus caballus) by projecting videos of positive and negative interactions between an unknown human experimenter (a “positive” experimenter or a “negative” experimenter) and an actor horse. The horses reacted emotionally while watching the videos, expressing behavioral (facial expressions and contact-seeking behavior) and physiological (heart rate) cues of positive emotions while watching the positive video and of negative emotions while watching the negative video. This result shows that the horses perceived the content of the videos and suggests an emotional contagion between the actor horse and the subjects. After the videos were projected, the horses took a choice test, facing the positive and negative experimenters in real life. The horses successfully used the interactions seen in the videos to discriminate between the experimenters. They touched the negative experimenter significantly more, which seems counterintuitive but can be interpreted as an appeasement attempt, based on the existing literature. This result suggests that horses can indirectly attribute a valence to a human experimenter by eavesdropping on a previous third-party interaction with a conspecific.

中文翻译：

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当他们在视频中观看人与人之间的积极和消极互动并将他们看到的内容转换为现实生活时，他们会感到情绪激动。

动物可以通过窃听第三方互动来间接收集有关其他人的有意义的信息。尤其是，窃听可用于间接地将负价或正价归因于一个人，并调整一个人对该人的未来行为。很少有研究关注非人类动物，特别是非灵长类动物的这种能力。在这里，我们调查了这种能力在国内马匹在第一时间（雅科仕caballus）来投影未知的人类实验者（“积极”实验者或“消极”实验者）与演员马之间的正负互动视频。这些马在观看视频时会做出情绪反应，在观看正向视频时会表现出积极情绪的行为（面部表情和寻求接触行为）和生理（心率）线索，而在观看负向视频时则会表现出负面情绪。该结果表明，马匹感知到了视频的内容，并暗示了演员马匹与对象之间的情感传染。视频放映后，马匹进行了选择测试，面对现实生活中的正面和负面实验者。马匹成功地利用视频中看到的互动来区分实验者。根据现有文献，他们对负面实验者的触动要大得多，这似乎违反直觉，但可以解释为interpreted靖尝试。该结果表明，通过窃听先前与同种动物的第三方交互，马可以将化合价间接归因于人类实验者。