Humans evaluate other agents’ behavior on a variety of different dimensions, including morally, from a very early age. For example, human infants as young as 6-months old prefer prosocial over antisocial others and demonstrate negative evaluations of antisocial others in a variety of paradigms (Hamlin et al. in Nature 450(7169):557, 2007; Dev Sci 13(6):923–929, 2010; Proc Natl Acad Sci 108(50):19931–19936, 2011). While these tendencies are well documented in the human species, less is known about whether similar preference emerge in non-human animals. Here, we explore this question by testing prosocial preferences in one non-human species: the domestic dog (Canis lupus familiaris). Given the ubiquity of dog–human social interactions, it is possible that dogs display human-like social evaluation tendencies. Unfortunately, prior research examining social evaluation in dogs has produced mixed results. To assess whether differences in methodology or training differences account for these contrasting results, we tested two samples of dogs with different training histories on an identical social evaluation task. Trained agility dogs approached a prosocial actor significantly more often than an antisocial actor, while untrained pet dogs showed no preference for either actor. These differences across dogs with different training histories suggest that while dogs may demonstrate preferences for prosocial others in some contexts, their social evaluation abilities are less flexible and less robust compared to those of humans.

从很小的时候开始，人类就在包括道德在内的各种不同维度上评估其他行为者的行为。例如，年龄在6个月大的婴儿较亲社会人士更喜欢亲社会，并在各种范式中表现出对反社会他人的负面评价（Hamlin等人，Nature 450（7169）：557，2007； Dev Sci 13（6） ）：923-929，2010；美国国家科学院院刊108（50）：19931-19936，2011）。尽管这些趋势已在人类物种中得到了很好的证明，但对于在非人类动物中是否会出现类似的偏好的了解却很少。在这里，我们通过测试一种非人类物种的亲社会偏好来探索这个问题：家犬（犬天狼犬））。鉴于狗与人之间的社会互动无处不在，狗可能表现出类似人的社会评价倾向。不幸的是，检查狗的社会评价的先前研究产生了不同的结果。为了评估方法上的差异或训练差异是否是这些对比结果的结果，我们在相同的社会评估任务中测试了两只具有不同训练历史的狗的样本。训练有素的敏捷犬比反社会角色更接近亲社会行为者，而未经训练的宠物犬对任何一个行为者都没有偏爱。不同训练历史的狗之间的这些差异表明，尽管在某些情况下狗可能表现出对亲社会他人的偏爱，但与人类相比，它们的社会评价能力较不灵活，也较不健全。