Punishment is sensitive to outside options in humans but not in cleaner fish (Labroides dimidiatus)

Across human and animal societies, punishment is used as a means of responding to cheating and modifying the behaviour of others. A growing body of work shows that human punishment decisions involve representing both the outcomes of transgressions as well as whether a transgressor chose to do wrong. An important question in comparative cognition is whether nonhuman animals demonstrate a similar sensitivity to choice when punishing. Understanding whether and to what extent animals inte-grate information about choice into their punishment decisions can shed light on the selective pressures and cognitive mechanisms that shape punishment. Here we explore this question by comparing pun-ishment in cooperative pairs of reef-dwelling cleaner wrasses, Labroides dimidiatus, and humans, Homo sapiens. In study 1, we investigate whether punishment in adult male cleaners is influenced by whether females had a choice to cheat. In study 2, we ask the same question of human adults, using a novel task inspired by the cooperative interactions between pairs of cleaners and their client fish. Our results support previous work finding that punishment of cheating in humans is sensitive to whether trans-gressors chose to cheat: they punished more when the alternative option was cooperation. However, we did not find a similar sensitivity to alternative options in cleaners. Our results provide a direct com-parison of the role of alternative options in punishment decisions in humans and a distantly related cooperative species. We suggest that important cognitive constraints may be in place that limit cleaners' ability to simultaneously represent both the choice a transgressor makes as well as the choices they could have made.(c) 2023 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.

Automated summary

Punishment is used in human and animal societies to respond to cheating. This study compares punishment in reef-dwelling cleaner wrasses and humans, and finds that humans are more sensitive to the transgressor's choice while punishing compared to the cleaner wrasses. The results shed light on the cognitive mechanisms that shape punishment decisions and the importance of choice in punishment.