Cleaner fish are sensitive to what their partners can and cannot see

Katherine Mcauliffe,Amanda Royka,Lindsey A Drayton,Redouan Bshary,Mélisande Aellen,Laurie R Santos

doi:10.1038/s42003-021-02584-2

Katherine Mcauliffe, Amanda Royka + Show 4 more

Open Access

https://doi.org/10.1038/s42003-021-02584-2

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Abstract

Much of human experience is informed by our ability to attribute mental states to others, a capacity known as theory of mind. While evidence for theory of mind in animals to date has largely been restricted to primates and other large-brained species, the use of ecologically-valid competitive contexts hints that ecological pressures for strategic deception may give rise to components of theory of mind abilities in distantly-related taxonomic groups. In line with this hypothesis, we show that cleaner wrasse (Labroides dimidiatus) exhibit theory of mind capacities akin to those observed in primates in the context of their cooperative cleaning mutualism. These results suggest that ecological pressures for strategic deception can drive human-like cognitive abilities even in very distantly related species.

Highlights

Much of human experience is informed by our ability to attribute mental states to others, a capacity known as theory of mind
Evidence for tracking what others see has been restricted to closely-related species such as non-human primates and other species who share a primate-like brain-to-body size ratio. This pattern raises the question of whether large brains are a prerequisite for theory of mind (ToM) components or whether selective pressures for successful deception may shape the evolution of ToM capacities even in smaller-brained species, like ectotherm vertebrates
Client fish approach cleaners in order to be cleaned of ectoparasites and dead skin cells, but cleaners prefer to feed on client mucus, where the consumption of the latter constitutes cheating[21]

Summary

Introduction

Much of human experience is informed by our ability to attribute mental states to others, a capacity known as theory of mind. We found that punishment did not vary as a function of the interaction between condition and female cooperation, measured as the number of flake items eaten (LRT, X21 = 0.11, p = 0.7) and the full model containing this term was no better than the null. When females first encountered the experimental conditions in block 1, their behavior conformed to our predictions: they were more likely to feed behind the opaque barrier when the male was visible.

Results

Conclusion