Behavioural Ecology Laboratory, Biology Institute, Faculty of Science, University of Neuchâtel, Neuchâtel, Switzerland.
PLoS One. 2023 Jun 23;18(6):e0287402. doi: 10.1371/journal.pone.0287402. eCollection 2023.
Transitive inference (TI) is a reasoning capacity that allows individuals to deduce unknown pair relationships from previous knowledge of other pair relationships. Its occurrence in a wide range of animals, including insects, has been linked to their ecological needs. Thus, TI should be absent in species that do not rely on such inferences in their natural lives. We hypothesized that the latter applies to the cleaner wrasse Labroides dimidiatus and tested this with 19 individuals using a five-term series (A > B > C > D > E) experiment. Cleaners first learned to prefer a food-rewarding plate (+) over a non-rewarding plate (-) in four plate pairs that imply a hierarchy from plate A to plate E (A+B-, B+C-, C+D-, D+E-), with the learning order counterbalanced between subjects. We then tested for spontaneous preferences in the unknown pairs BD (transitive inference task) and AE (as a control for anchors), interspersed between trials involving a mix of all known adjacent pairs. The cleaners systematically preferred A over E and showed good performance for A+B- and D+E- trials. Conversely, cleaners did not prefer B over D. These results were unaffected by the reinforcement history, but the order of learning of the different pairs of plates had a main impact on the remembrance of the initial training pairs. Overall, cleaners performed randomly in B+C- and C+D- trials. Thus, a memory constraint may have prevented subjects from applying TI. Indeed, a parallel study on cleaner wrasse provided positive evidence for TI but was achieved following extensive training on the non-adjacent pairs which may have over-ridden the ecological relevance of the task.
传递性推理（TI）是一种推理能力，它允许个体从先前对其他成对关系的了解中推断出未知的成对关系。它在包括昆虫在内的广泛动物中出现，与它们的生态需求有关。因此，在其自然生活中不依赖于此类推理的物种中，TI 应该不存在。我们假设后者适用于清洁濑鱼 Labroides dimidiatus，并用 19 只个体通过一个五项系列（A>B>C>D>E）实验来检验这一假设。清洁濑鱼首先在四个盘子对中学会了更喜欢有食物奖励的盘子（+）而不是没有奖励的盘子（-），这四个盘子对从 A 盘到 E 盘暗示了一个等级，学习顺序在被试之间平衡。然后，我们在未知的 BD 对（传递性推理任务）和 AE 对（作为对锚的控制）中测试了自发偏好，在涉及所有已知相邻对的混合试验之间穿插进行。清洁濑鱼系统地更喜欢 A 而不是 E，并且在 A+B-和 D+E-试验中表现良好。相反，清洁濑鱼并没有更喜欢 B 而不是 D。这些结果不受强化历史的影响，但不同盘子对的学习顺序对初始训练对的记忆有主要影响。总体而言，清洁濑鱼在 B+C-和 C+D-试验中表现随机。因此，记忆限制可能阻止了清洁濑鱼应用 TI。事实上，对清洁濑鱼的平行研究提供了 TI 的积极证据，但这是在对非相邻对进行广泛训练后实现的，这可能会忽略任务的生态相关性。
