Tromp D, Meunier H, Roeder J J
Université de Strasbourg, IPHC, Strasbourg, France; CNRS, UDS, UMR7178, Strasbourg, France; Centre de Primatologie de l'Université de Strasbourg, Niederhausbergen, France.
Am J Primatol. 2015 Mar;77(3):338-45. doi: 10.1002/ajp.22349. Epub 2014 Oct 18.
When confronted with tasks involving reasoning instead of simple learning through trial and error, lemurs appeared to be less competent than simians. Our study aims to investigate lemurs' capability for transitive inference, a form of deductive reasoning in which the subject deduces logical conclusions from preliminary information. Transitive inference may have an adaptative function, especially in species living in large, complex social groups and is proposed to play a major role in rank estimation and establishment of dominance hierarchies. We proposed to test the capacities of reasoning using transitive inference in two species of lemurs, the brown lemur (Eulemur fulvus) and the black lemur (Eulemur macaco), both living in multimale-multifemale societies. For that purpose, we designed an original setup providing, for the first time in this kind of cognitive task, pictures of conspecifics' faces as stimuli. Subjects were trained to differentiate six photographs of unknown conspecifics named randomly from A to F to establish the order A > B > C > D > E > F and select consistently the highest-ranking photograph in five adjacent pairs AB, BC, CD, DE, and EF. Then lemurs were presented with the same adjacent pairs and three new and non-adjacent pairs BD, BE, CE. The results showed that all subjects correctly selected the highest-ranking photograph in every non-adjacent pair, reflecting lemurs' capacity for transitive inference. Our results are discussed in the context of the still debated current theories about the mechanisms underlying this specific capacity.
当面对涉及推理而非简单试错学习的任务时，狐猴似乎比猿猴能力更弱。我们的研究旨在调查狐猴的传递性推理能力，这是一种演绎推理形式，主体可根据初步信息得出逻辑结论。传递性推理可能具有适应性功能，尤其是在生活于大型复杂社会群体中的物种中，并且被认为在等级估计和优势等级制度的建立中起主要作用。我们提议测试两种狐猴，即褐狐猴（Eulemur fulvus）和黑狐猴（Eulemur macaco）的传递性推理能力，它们都生活在多雄多雌的社会中。为此，我们设计了一种原始装置，在这类认知任务中首次提供同种个体面部照片作为刺激物。训练受试狐猴区分六张随机命名为A到F的未知同种个体照片，以建立A > B > C > D > E > F的顺序，并在五个相邻对AB、BC、CD、DE和EF中始终选择等级最高的照片。然后向狐猴展示相同的相邻对以及三个新的非相邻对BD、BE、CE。结果表明，所有受试狐猴在每个非相邻对中都正确选择了等级最高的照片，这反映了狐猴的传递性推理能力。我们的研究结果将在关于这种特定能力潜在机制的当前理论仍存在争议的背景下进行讨论。
