在复杂的动物社会中，个体能够识别群体成员，了解其社会地位，推断各自之间的关系。可能的相互作用的数量随着群体规模的增加而迅速增加，所以较大群体的成员不能单纯依靠直接相互作用来判断个体之间的关系。这说明，对群居物种的成员来说，通过评估其他成员之间的相互作用来间接判断个体关系可能是很重要的。现在，这种“及物”推断能力首次在非人类动物中发现了。在一个精巧设计的实验中，研究人员让实验动物一对一地碰面，用单个去壳花生作诱饵。他们发现，高度社会化的实验鸟pinyon jays能够就它们自己相对于那些它们发现与已知个体发生相互作用的陌生者的统治地位做出复杂的推断。
Pinyon jays use transitive inference to predict social dominance
GUILLERMO PAZ-Y-MIÑO C1, ALAN B. BOND1, ALAN C. KAMIL1,2 & RUSSELL P. BALDA3
1 Center for Avian Cognition, School of Biological Sciences and
2 Department of Psychology, University of Nebraska, Lincoln, Nebraska 68588, USA
3 Department of Biological Sciences, Northern Arizona University, Flagstaff, Arizona 86011, USA
Correspondence and requests for materials should be addressed to A.B.B. (abond@unl.edu) or A.C.K. (akamil@unl.edu).
Living in large, stable social groups is often considered to favour the evolution of enhanced cognitive abilities, such as recognizing group members, tracking their social status and inferring relationships among them. An individual's place in the social order can be learned through direct interactions with others, but conflicts can be time-consuming and even injurious. Because the number of possible pairwise interactions increases rapidly with group size, members of large social groups will benefit if they can make judgments about relationships on the basis of indirect evidence. Transitive reasoning should therefore be particularly important for social individuals, allowing assessment of relationships from observations of interactions among others. Although a variety of studies have suggested that transitive inference may be used in social settings, the phenomenon has not been demonstrated under controlled conditions in animals. Here we show that highly social pinyon jays (Gymnorhinus cyanocephalus) draw sophisticated inferences about their own dominance status relative to that of strangers that they have observed interacting with known individuals. These results directly demonstrate that animals use transitive inference in social settings and imply that such cognitive capabilities are widespread among social species.
