Transitive inference in cleaner wrasses (Labroides dimidiatus).

Takashi Hotta,Hika Kuroshima,Kazuo Fujita,Masanori Kohda,Yuya Hataji,Kentaro Ueno,Nicolas Chaline

doi:10.1371/journal.pone.0237817

Takashi Hotta, Hika Kuroshima + Show 5 more

Open Access

https://doi.org/10.1371/journal.pone.0237817

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Abstract

Transitive inference (TI) is the ability to infer unknown relationships from previous information. To test TI in non-human animals, transitive responding has been examined in a TI task where non-adjacent pairs were presented after premise pair training. Some mammals, birds and paper wasps can pass TI tasks. Although previous studies showed that some fish are capable of TI in the social context, it remains unclear whether fish can pass TI task. Here, we conducted a TI task in cleaner wrasses (Labroides dimidiatus), which interact with various client fishes and conspecifics. Because they make decisions based on previous direct and indirect interactions in the context of cleaning interactions, we predicted that the ability of TI is beneficial for cleaner fish. Four tested fish were trained with four pairs of visual stimuli in a 5-term series: A-B+, B-C+, C-D+, and D-E+ (plus and minus denote rewards and non-rewards, respectively). After training, a novel pair, BD (BD test), was presented wherein the fish chose D more frequently than B. In contrast, reinforcement history did not predict the choice D. Our results suggest that cleaner fish passed the TI task, similar to mammals and birds. Although the mechanism underlying transitive responding in cleaner fish remains unclear, this work contributes to understanding cognitive abilities in fish.

Highlights

Transitive inference (TI) refers to the ability to estimate relationships between items that have never been presented together based on previous information [1]
We tested whether cleaner fish, Labroides dimidiatus, exhibited transitive responding in a TI task
Our results showed that the four tested cleaner fish chose plate D over B, both of which had never been presented together prior to the test phase. This suggests that cleaner fish can respond transitively and is the first demonstration of a TI task in fish [1]

Summary

Introduction

Transitive inference (TI) refers to the ability to estimate relationships between items that have never been presented together based on previous information [1]. From the premises ‘A is smaller than B’ and ‘B is smaller than C’, it follows that ‘A is smaller than C’ the premise of A and C has not been presented previously. Subjects were trained with a set of four stimuli simultaneous discrimination: A-B+, B-C+, C-D +, and D-E+, in which plus and minus denote reward and non-reward, respectively. After training, they chose D over B in the non-adjacent pair (i.e. a BD test) the pair had never been presented during training and both stimuli were reinforced and non-

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Results

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